担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.pmpp.2023.102019

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.pmpp.2023.101970

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Frontiers Media {SA}  

<jats:p>Plants protect themselves from microorganisms by inducing pattern-triggered immunity (PTI) <jats:italic>via</jats:italic> recognizing microbe-associated molecular patterns (MAMPs), conserved across many microbes. Although the MAMP perception mechanism and initial events during PTI have been well-characterized, knowledge of the transcriptomic changes in plants, especially monocots, is limited during the intermediate and terminal stages of PTI. Here, we report a time-series high-resolution RNA-sequencing (RNA-seq) analysis during PTI in the leaf disks of <jats:italic>Brachypodium distachyon</jats:italic>. We identified 6,039 differentially expressed genes (DEGs) in leaves sampled at 0, 0.5, 1, 3, 6, and 12 hours after treatment (hat) with the bacterial flagellin peptide flg22. The k-means clustering method classified these DEGs into 10 clusters (6 upregulated and 4 downregulated). Based on the results, we selected 10 PTI marker genes in <jats:italic>B. distachyon</jats:italic>. Gene ontology (GO) analysis suggested a tradeoff between defense responses and photosynthesis during PTI. The data indicated the recovery of photosynthesis started at least at 12 hat. Over-representation analysis of transcription factor genes and cis-regulatory elements in DEG promoters implied the contribution of 12 WRKY transcription factors in plant defense at the early stage of PTI induction.</jats:p>

DOI： 10.3389/fpls.2022.1004184

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s10327-022-01077-2

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その他リンク： https://link.springer.com/article/10.1007/s10327-022-01077-2/fulltext.html

掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

DOI： 10.1111/mpp.13198

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その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/mpp.13198

掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

Rhizoctonia solani is a necrotrophic plant pathogen with a wide host range. R. solani is a species complex consisting of thirteen anastomosis groups (AGs) defined by compatibility of hyphal fusion reaction and subgroups based on cultural morphology. The relationship between such classifications and host specificity remains elusive. Here, we investigated the pathogenicity of seventeen R. solani isolates (AG-1 to 7) in Japan towards Arabidopsis thaliana using leaf and soil inoculations. The tested AGs, except AG-3 and AG-6, induced symptoms in both methods with variations in pathogenicity. The virulence levels differed even within the same AG and subgroup. Some isolates showed tissue-specific infection behavior. Thus, the AGs and their subgroups are suggested to be not enough to define the virulence (host and tissue specificity) of R. solani. We also evaluated the virulence of the isolates on Arabidopsis plants pretreated with salicylic acid, jasmonic acid, and ethylene. No obvious effects were detected on the symptom formation by the virulence isolates, but ethylene and salicylic acid slightly enhanced the susceptibility to the weak and nonvirulent isolates. R. solani seems to be able to overcome the induced defense by these phytohormones in the infection to Arabidopsis.

DOI： 10.3390/life12010076

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Pseudomonas syringae pv. tabaci 6605 (Pta6605) is a foliar plant pathogen that causes wildfire disease on tobacco plants. It requires chemotaxis to enter plants and establish infection. While chemotactic signals appear to be the main mechanism by which Pta6605 performs directional movement, the involvement of aerotaxis or energy taxis by this foliar pathogen is currently unknown. Based on domain structures and similarity with more than 50 previously identified putative methyl-accepting chemotaxis proteins (MCPs), the genome of Pta6605 encodes three potential aerotaxis transducers. We identified AerA as the main aerotaxis transducer and found that it possesses a taxis-to-serine-and-repellent (Tsr)-like domain structure that supports a periplasmic 4HB-type ligand-binding domain (LBD). The secondary aerotaxis transducer, AerB, possesses a cytosolic PAS-type LBD, similar to the Aer of Escherichia coli and Pseudomonas aeruginosa. Aerotaxis ability by single and double mutant strains of aerA and aerB was weaker than that by wild-type Pta6605. On the other hand, another cytosolic PAS-type LBD containing MCP did not make a major contribution to Pta6605 aerotaxis in our assay system. Furthermore, mutations in aerotaxis transducer genes did not affect surface motility or chemotactic attraction to yeast extract. Single and double mutant strains of aerA and aerB showed less colonization in the early stage of host plant infection and lower biofilm production than wild-type Pta6605. These results demonstrate the presence of aerotaxis transducers and their contribution to host plant infection by Pta6605.

DOI： 10.1264/jsme2.ME21076

PubMed

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Korean Society of Plant Pathology  

Ralstonia syzygii subsp. indonesiensis (Rsi, former name: Ralstonia solanacearum phylotype IV) PW1001, a causal agent of potato wilt disease, induces hypersensitive response (HR) on its non-host eggplant (Solanum melongena cv. Senryo-nigou). The disaccharide trehalose is involved in abiotic and biotic stress tolerance in many organisms. We found that trehalose is required for eliciting HR on eggplant by plant pathogen Rsi PW1001. In R. solanacearum, it is known that the OtsA/OtsB pathway is the dominant trehalose synthesis pathway, and otsA and otsB encode trehalose-6-phosphate (T6P) synthase and T6P phosphatase, respectively. We generated otsA and otsB mutant strains and found that these mutant strains reduced the bacterial trehalose concentration and HR induction on eggplant leaves compared to wild-type. Trehalose functions intracellularly in Rsi PW1001 because addition of exogenous trehalose did not affect the HR level and ion leakage. Requirement of trehalose in HR induction is not common in R. solanacearum species complex because mutation of otsA in Ralstonia pseudosolanacearum (former name: Ralstonia solanacearum phylotype I) RS1002 did not affect HR on the leaves of its non-host tobacco and wild eggplant Solanum torvum. Further, we also found that each otsA and otsB mutant had reduced ability to grow in a medium containing NaCl and sucrose, indicating that trehalose also has an important role in osmotic stress tolerance.

DOI： 10.5423/ppj.oa.06.2021.0087

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その他リンク： http://ppjonline.org/journal/view.php?doi=10.5423/PPJ.OA.06.2021.0087

掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.micres.2021.126869

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.bbrep.2021.100944

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER SOC MICROBIOLOGY  

Pseudomonas amygdali pv. tabaci strain 6605 is the bacterial pathogen causing tobacco wildfire disease that has been used as a model for elucidating virulence mechanisms. Here, we present the complete genome sequence of P. amygdali pv. tabaci 6605 as a circular chromosome from reads using a PacBio sequencer.

DOI： 10.1128/MRA.00405-21

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s00438-020-01745-y

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その他リンク： http://link.springer.com/article/10.1007/s00438-020-01745-y/fulltext.html

掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s10327-020-00961-z

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その他リンク： http://link.springer.com/article/10.1007/s10327-020-00961-z/fulltext.html

掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

<title>Abstract</title>
<italic>Rhizoctonia solani</italic> is a necrotrophic phytopathogen belonging to basidiomycetes. It causes rice sheath blight which inflicts serious damage in rice production. The infection strategy of this pathogen remains unclear. We previously demonstrated that salicylic acid-induced immunity could block <italic>R. solani</italic> AG-1 IA infection in both rice and <italic>Brachypodium distachyon</italic>. <italic>R. solani</italic> may undergo biotrophic process using effector proteins to suppress host immunity before necrotrophic stage. To identify pathogen genes expressed at the early infection process, here we developed an inoculation method using <italic>B. distachyon</italic> which enables to sample an increased amount of semi-synchronous infection hyphae. Sixty-one <italic>R. solani secretory effector-like protein</italic> genes (<italic>RsSEPGs</italic>) were identified using in silico approach with the publicly available gene annotation of <italic>R. solani</italic> AG-1 IA genome and our RNA-sequencing results obtained from hyphae grown on agar medium. Expression of <italic>RsSEPGs</italic> was analyzed at 6, 10, 16, 24, and 32 h after inoculation by a quantitative reverse transcription-polymerase chain reaction and 52 genes could be detected at least on a single time point tested. Their expressions showed phase-specific patterns which were classified into 6 clusters. The 23 <italic>RsSEPGs</italic> in the cluster 1–3 and 29 <italic>RsSEPGs</italic> in the cluster 4–6 are expected to be involved in biotrophic and necrotrophic interactions, respectively.

DOI： 10.1038/s41598-020-71968-x

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その他リンク： http://www.nature.com/articles/s41598-020-71968-x

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：KOREAN SOC PLANT PATHOLOGY  

Pseudomonas syringae pv. tabaci 6605 has two multidrug resistance (MDR) efflux pump transporters, MexAB-OprM and MexEF-OprN. To understand the role of these MDR efflux pumps in virulence, we generated deletion mutants, Delta mexB, Delta mexF, and Delta mexB Delta mexF, and investigated their sensitivity to plant-derived antimicrobial compounds, antibiotics, and virulence. Growth inhibition assays with KB soft agar plate showed that growth of the wild-type (WT) was inhibited by 5 mu l of 1 M catechol and 1 M coumarin but not by other plant-derived potential antimicrobial compounds tested including phytoalexins. The sensitivity to these compounds tended to increase in Delta mexB and Delta mexB Delta mexF mutants. The Delta mexB Delta mexF mutant was also sensitive to 2 M acetovanillone. The mexAB-oprM was constitutively expressed, and activated in the Delta mexF and Delta mexB Delta mexF mutant strains. The swarming and swimming motilities were impaired in Delta mexF and Delta mexB Delta rnexF mutants. The flood inoculation test indicated that bacterial populations in all mutant strains were significantly lower than that of WT, although all mutants and WT caused similar disease symptoms. These results indicate that MexAB-OprM extrudes plant-derived catechol, acetovanillone, or coumarin, and contributes to bacterial virulence. Furthermore, MexAB-OprM and MexEF-OprN complemented each other's functions to some extent.

DOI： 10.5423/PPJ.OA.11.2019.0273

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER JAPAN KK  

Saccharin is generated from probenazole (PBZ) in plants and acts as a plant defense activator. Our study of the mechanism underlying saccharin-induced systemic acquired resistance in Arabidopsis thaliana suggests an antagonistic interaction between salicylic acid (SA)- and jasmonic acid (JA)-signaling as revealed through gene expression analyses. In wild-type plants (Col-0) exposed to saccharin, there was a consistent increase in callose deposition and in expression of SA-marker genes, PR1 and PR2, which coincided with a decrease in expression of JA-marker genes such as VSP2, LOX2 and PDF1.2. Actually, pretreatment of Col-0 with saccharin or PBZ conferred resistance to Pseudomonas syringae pv. tomato DC3000, but not to Pectobacterium carotovorum subsp. carotovorum, Botrytis cinerea, or Colletotrichum higginsianum. Enhanced expression of SA- and JA-marker genes and the augmented deposition of callose were evident after a challenge with virulent DC3000 in saccharin-pretreated plants. Consistently, pretreatment of saccharin and PBZ with SA- and JA-defective mutants led to diminished resistance in NahG-transgenic and npr1 mutant plants, but not in jar1 mutant plants, suggesting that saccharin and PBZ induce resistance in A. thaliana against Pto DC3000 mainly via activation of SA-signaling, leading to suppression of JA/ET-signaling and vice versa. Collectively, an antagonism between SA- and JA-signaling conditioned by saccharin renders resistance to a specific pathogen in Arabidopsis.

DOI： 10.1007/s10327-019-00899-x

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER JAPAN KK  

Quorum sensing (QS) is a mechanism for bacterial cell-cell communication using QS signals. N-acyl-homoserine lactones (AHLs), QS signals in Pseudomonas syringae pv. tabaci (Pta) 6605, are synthesized by an AHL synthase (PsyI) and recognized by the cognate transcription factor PsyR. To reveal the role of PsyR in virulence, we generated a psyR mutant and complemented strains of Pta 6605 and found that the psyR mutant is remarkably reduced in AHL production and ability to cause disease and propagate in host tobacco leaves. The phenotypes of complemented strains were restored to that of the wild type (WT). Because the psyR mutant lost nearly all AHL production, we investigated the function of PsyR in the transcription of psyI and production of AHL. Electrophoretic mobility shift assays suggested that the recombinant PsyR protein binds the promoter region of psyI but not psyR without AHL. The addition of AHL did not significantly affect this binding. The binding core sequence of this region was identified as a 20-bp lux box-like sequence. To reveal the function of PsyR and AHL on psyI transcription, we constructed a psyI promoter::lacZYA chimeric reporter gene, and inserted it into the WT and psyI mutant of Pta 6605. beta-galactosidase activity increased in a bacterial density-dependent manner in the WT and also in a psyI mutant after the addition of exogenous AHL. These results indicate that the solo PsyR binds the lux box in the psyI promoter and activates transcription in the concomitant presence of AHL.

DOI： 10.1007/s10327-019-00893-3

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER JAPAN KK  

Saccharin and its parental compound probenazole (PBZ) are plant activators of effective defense responses to (hemi) biotrophic pathogens. Here, we demonstrate that pretreatment of wheat seedlings with saccharin or PBZ results in a significant reduction of powdery mildew caused by Blumeria graminis f. sp. tritici. Transcriptional analysis revealed the expression of 15 defense-related genes including PR genes, WCI genes, LOX, AOS, NPR1, PAL and WRKY genes in wheat seedlings exposed to either saccharin or PBZ. Moreover, the saccharin- and PBZ-enhanced expression of those genes during fungal infection further proved a close correlation with increased resistance in wheat.

DOI： 10.1007/s10327-019-00900-7

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER JAPAN KK  

An ethyl acetate extract of Arabidopsis thaliana plants was tested for the presence of endogenous suppressor(s) (ES), and the active fraction, which partitioned into water phase contained a molecule(s) < 3000 Da based on a rough estimate using sized membrane filters. Foliar application of the ES enabled typically nonpathogenic fungi (non-adapted pathogens) to cause disease symptoms on A. thaliana. Consistently, the ES fraction severely suppressed the oxidative burst and the expression of defense-related genes such as FRK1, NHO1, WRKY22, WRKY29, PEN2, and PEN3 in plants challenged with non-adapted fungus Colletotrichum gloeosporioides or the fungal elicitor chitin.

DOI： 10.1007/s10327-019-00897-z

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

γ-Aminobutyric acid (GABA) is a widely distributed non-proteinogenic amino acid that accumulates in plants under biotic and abiotic stress conditions. Recent studies suggested that GABA also functions as an intracellular signaling molecule in plants and in signals mediating interactions between plants and phytopathogenic bacteria. However, the molecular mechanisms underlying GABA responses to bacterial pathogens remain unknown. In the present study, a GABA receptor, named McpG, was conserved in the highly motile plant-pathogenic bacteria Pseudomonas syringae pv. tabaci 6605 (Pta6605). We generated a deletion mutant of McpG to further investigate its involvement in GABA chemotaxis using quantitative capillary and qualitative plate assays. The wild-type strain of Pta6605 was attracted to GABA, while the ΔmcpG mutant abolished chemotaxis to 10‍ ‍mM GABA. However, ΔmcpG retained chemotaxis to proteinogenic amino acids and succinic semialdehyde, a structural analog of GABA. Furthermore, ΔmcpG was unable to effectively induce disease on host tobacco plants in three plant inoculation assays: flood, dip, and infiltration inoculations. These results revealed that the GABA sensing of Pta6605 is important for the interaction of Pta6605 with its host tobacco plant.

DOI： 10.1264/jsme2.ME20114

PubMed

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER JAPAN KK  

PRX34 mediates the oxidative burst in Arabidopsis. Here we characterized two additional Arabidopsis prx34 null mutants (prx34-2, prx34-3), besides the well-studied prx34-1. Due to a decrease in corresponding peroxidase, the activity that generates reactive oxygen species (ROS) was significantly lower in cell wall extracts of prx34-2 and prx34-3 plants. Consistently, the prx34-2 and prx34-3 exhibited reduced accumulation both of ROS and callose in Flg22-elicitor-treated leaves, leading to enhanced susceptibility to bacterial and fungal pathogens. In contrast, ectopic expression of PRX34 in the wild type caused enhanced resistance. PRX34 is thus a component for disease resistance in Arabidopsis.

DOI： 10.1007/s10327-019-00863-9

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.micres.2018.06.005

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s00438-018-1430-9

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10327-017-0756-1

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/nph.14849

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：FRONTIERS MEDIA SA  

Ascochyta (Mycosphaerella) blight on cultivated peas is primarily caused by infection through asexual spores (pycnospores) of Mycosphaerella pinodes (Berk. et Blox.) Vestergren [recently renamed Peyronellaea pinodes (Berk. & A. Bloxam) Aveskamp, Gruyter & Verkley]. Using a model pathosystem involving Medicago truncatula and Mycosphaerella pinodes strain OMP-1, we examined the histology and ultrastructure of early infection events and fungal development including penetration by appressoria, vegetative growth of infection hyphae, and host responses. On the susceptible ecotype R108-1, pycnospores germinated and grew over the surface of the epidermis, then formed an appressoria and penetrated the cuticle. Beneath the cuticle, the infection peg expanded into a hyphae that grew within the outer wall of the epidermis. Subsequently, the hyphae penetrated down within mesophyll cells and proliferated vigorously, eventually, forming asexual fruiting bodies (pycnidia). In contrast, successful penetration and subsequent growth of infection hyphae were considerably restricted in the ecotype Caliph. Detected by its reaction with cerium chloride (CeCl3) to generate electron-dense cerium perhydroxides in transmission electron micrographs, hydrogen peroxide (H2O2) accumulated in epidermal and mesophyll cells of Caliph challenged with pycnospores of M. pinodes. This intracellular localization was confirmed by energydispersive X-ray spectroscopy. Our observations thus indicate that the oxidative burst reaction leading to the generation of reactive oxygen species is associated with a local host defense response in Caliph, since no clear H2O2 accumulation was detectable in susceptible R108-1. Indeed, aberrant hyphae such as intrahyphal hyphae and dead hyphae, probably due to a local defense elicited by the fungus, were abundant in Caliph but not in R108-1. Our results on the cellular interactions between the fungus and host cells provide additional insights to understand foliar infection by M. pinodes on cultivated peas.

DOI： 10.3389/fpls.2017.01132

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記述言語：日本語   出版者・発行元：一般社団法人 電気学会  

<p>The spacecrafts need high-voltage power generation for high power. However, the high voltage can cause severe discharge problem on spacecrafts. This paper describes the mechanism of spacecraft charging and discharging. The mitigation methods are also mentioned.</p>

DOI： 10.1541/ieejpes.137.698

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier B.V.  

The identification of mycoviruses contributes greatly to understanding of the diversity and evolutionary aspects of viruses. Powdery mildew fungi are important and widely studied obligate phytopathogenic agents, but there has been no report on mycoviruses infecting these fungi. In this study, we used a deep sequencing approach to analyze the double-stranded RNA (dsRNA) segments isolated from field-collected samples of powdery mildew fungus-infected red clover plants in Japan. Database searches identified the presence of at least ten totivirus (genus Totivirus)-like sequences, termed red clover powdery mildew-associated totiviruses (RPaTVs). The majority of these sequences shared moderate amino acid sequence identity with each other (&lt
44%) and with other known totiviruses (&lt
59%). Nine of these identified sequences (RPaTV1a, 1b and 2–8) resembled the genome of the prototype totivirus, Saccharomyces cerevisiae virus-L-A (ScV-L-A) in that they contained two overlapping open reading frames (ORFs) encoding a putative coat protein (CP) and an RNA dependent RNA polymerase (RdRp), while one sequence (RPaTV9) showed similarity to another totivirus, Ustilago maydis virus H1 (UmV-H1) that encodes a single polyprotein (CP-RdRp fusion). Similar to yeast totiviruses, each ScV-L-A-like RPaTV contains a –1 ribosomal frameshift site downstream of a predicted pseudoknot structure in the overlapping region of these ORFs, suggesting that the RdRp is translated as a CP-RdRp fusion. Moreover, several ScV-L-A-like sequences were also found by searches of the transcriptome shotgun assembly (TSA) libraries from rust fungi, plants and insects. Phylogenetic analyses show that nine ScV-L-A-like RPaTVs along with ScV-L-A-like sequences derived from TSA libraries are clustered with most established members of the genus Totivirus, while one RPaTV forms a new distinct clade with UmV-H1, possibly establishing an additional genus in the family. Taken together, our results indicate the presence of diverse, novel totiviruses in the powdery mildew fungus populations infecting red clover plants in the field.

DOI： 10.1016/j.virusres.2016.05.011

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BIOMED CENTRAL LTD  

Background: Brachypodium distachyon is a promising model plants for grasses. Infections of Brachypodium by various pathogens that severely impair crop production have been reported, and the species accordingly provides an alternative platform for investigating molecular mechanisms of pathogen virulence and plant disease resistance. To date, we have a broad picture of plant immunity only in Arabidopsis and rice; therefore, Brachypodium may constitute a counterpart that displays the commonality and uniqueness of defence systems among plant species. Phytohormones play key roles in plant biotic stress responses, and hormone-responsive genes are used to qualitatively and quantitatively evaluate disease resistance responses during pathogen infection. For these purposes, defence-related phytohormone marker genes expressed at time points suitable for defence-response monitoring are needed. Information about their expression profiles over time as well as their response specificity is also helpful. However, useful marker genes are still rare in Brachypodium.
Results: We selected 34 candidates for Brachypodium marker genes on the basis of protein-sequence similarity to known marker genes used in Arabidopsis and rice. Brachypodium plants were treated with the defence-related phytohormones salicylic acid, jasmonic acid and ethylene, and their transcription levels were measured 24 and 48 h after treatment. Two genes for salicylic acid, 7 for jasmonic acid and 2 for ethylene were significantly induced at either or both time points. We then focused on 11 genes encoding pathogenesis-related (PR) 1 protein and compared their expression patterns with those of Arabidopsis and rice. Phylogenetic analysis suggested that Brachypodium contains several PR1-family genes similar to rice genes. Our expression profiling revealed that regulation patterns of some PR1 genes as well as of markers identified for defence-related phytohormones are closely related to those in rice.
Conclusion: We propose that the Brachypodium immune hormone marker genes identified in this study will be useful to plant pathologists who use Brachypodium as a model pathosystem, because the timing of their transcriptional activation matches that of the disease resistance response. Our results using Brachypodium also suggest that monocots share a characteristic immune system, defined as the common defence system, that is different from that of dicots.

DOI： 10.1186/s12870-016-0749-9

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER SCIENCE BV  

The identification of mycoviruses contributes greatly to understanding of the diversity and evolutionary aspects of viruses. Powdery mildew fungi are important and widely studied obligate phytopathogenic agents, but there has been no report on mycoviruses infecting these fungi. In this study, we used a deep sequencing approach to analyze the double-stranded RNA (dsRNA) segments isolated from field collected samples of powdery mildew fungus-infected red clover plants in Japan. Database searches identified the presence of at least ten totivirus (genus Totivirus)-like sequences, termed red clover powdery mildew-associated totiviruses (RPaTVs). The majority of these sequences shared moderate amino acid sequence identity with each other (&lt;44%) and with other known totiviruses (&lt;59%). Nine of these identified sequences (RPaTV1a, 1b and 2-8) resembled the genome of the prototype totivirus, Saccharomyces cerevisiae virus-L-A (ScV-L-A) in that they contained two overlapping open reading frames (ORFs) encoding a putative coat protein (CP) and an RNA dependent RNA polymerase (RdRp), while one sequence (RPaTV9) showed similarity to another totivirus, Ustilago maydis virus H1 (UmV-H1) that encodes a single polyprotein (CP-RdRp fusion). Similar to yeast totiviruses, each ScV-L-A-like RPaTV contains a-1 ribosomal frameshift site downstream of a predicted pseudoknot structure in the overlapping region of these ORFs, suggesting that the RdRp is translated as a CP-RdRp fusion. Moreover, several ScV-L-A-like sequences were also found by searches of the transcriptome shotgun assembly (TSA) libraries from rust fungi, plants and insects. Phylogenetic analyses show that nine ScV-L-A-like RPaTVs along with ScV-L-A-like sequences derived from TSA libraries are clustered with most established members of the genus Totivirus, while one RPaTV forms a new distinct Glade with UmV-H1, possibly establishing an additional genus in the family. Taken together, our results indicate the presence of diverse, novel totiviruses in the powdery mildew fungus populations infecting red clover plants in the field. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.virusres.2015.11.015

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記述言語：英語   出版者・発行元：Nature Publishing Group  

Arabidopsis thaliana leucine-rich repeat-containing (NLR) proteins RPS4 and RRS1, known as dual resistance proteins, confer resistance to multiple pathogen isolates, such as the bacterial pathogens Pseudomonas syringae and Ralstonia solanacearum and the fungal pathogen Colletotrichum higginsianum. RPS4 is a typical Toll/interleukin 1 Receptor (TIR)-type NLR, whereas RRS1 is an atypical TIR-NLR that contains a leucine zipper (LZ) motif and a C-terminal WRKY domain. RPS4 and RRS1 are localised near each other in a head-to-head orientation. In this study, direct mutagenesis of the C-terminal LZ motif in RRS1 caused an autoimmune response and stunting in the mutant. Co-immunoprecipitation analysis indicated that full-length RPS4 and RRS1 are physically associated with one another. Furthermore, virus-induced gene silencing experiments showed that hypersensitive-like cell death triggered by RPS4/LZ motif-mutated RRS1 depends on EDS1. In conclusion, we suggest that the RRS1-LZ motif is crucial for the regulation of the RPS4/RRS1 complex.

DOI： 10.1038/srep18702

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.pmpp.2016.02.005

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.pmpp.2016.02.006

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10327-015-0621-z

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/mpp.12187

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER JAPAN KK  

Ecto-apyrase(s) participates in cell-wall-associated defense through ATP hydrolysis. Here we analyzed Medicago truncatula genes through cDNA screening and in silico analyses against known databases. This study revealed seven genes, five of which (MtAPY1;1 to MtAPY1;5) are members of a legume-specific family, whereas two genes (MtAPY2;1 and MtAPY2;2) are close to those in other plants. Agrobacterium-based transient expression in Nicotiana benthamiana, combined with a c-myc epitope tag technology, confirmed that the MtAPY1;1 is a secreted protein. Transient expression of MtAPY1;1 in leaves of N. benthamiana restricted disease development by a virulent fungus, suggesting a role in disease resistance.

DOI： 10.1007/s10327-014-0510-x

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY  

Ralstonia solanacearum is a Gram-negative soil-borne bacterium that causes bacterial wilt disease in more than 200 plant species, including economically important Solanaceae species. In R. solanacearum, the hypersensitive response and pathogenicity (Hrp) type III secretion system is required for both the ability to induce the hypersensitive response (HR) in nonhost plants and pathogenicity in host plants. Recently, 72 effector genes, called rip (Ralstonia protein injected into plant cells), have been identified in R. solanacearum RS1000. RS1002, a spontaneous nalixidic acid-resistant derivative of RS1000, induced strong HR in the nonhost wild eggplant Solanum torvum in an Hrp-dependent manner. An Agrobacterium-mediated transient expression system revealed that Rip36, a putative Zn-dependent protease effector of R. solanacearum, induced HR in S. torvum. A mutation in the putative Zn-binding motif (E149A) completely abolished the ability to induce HR. In agreement with this result, the RS1002-derived Delta rip36 and rip36E149A mutants lost the ability to induce HR in S. torvum. An E149A mutation had no effect on the translocation of Rip36 into plant cells. These results indicate that Rip36 is an avirulent factor that induces HR in S. torvum and that a putative Zn-dependent protease motif is essential for this activity.

DOI： 10.1111/mpp.12079

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Ralstonia solanacearum is a Gram-negative soil-borne bacterium that causes bacterial wilt disease in more than 200 plant species, including economically important Solanaceae species. In R. solanacearum, the hypersensitive response and pathogenicity (Hrp) type III secretion system is required for both the ability to induce the hypersensitive response (HR) in nonhost plants and pathogenicity in host plants. Recently, 72 effector genes, called rip (Ralstonia protein injected into plant cells), have been identified in R. solanacearum RS1000. RS1002, a spontaneous nalixidic acid-resistant derivative of RS1000, induced strong HR in the nonhost wild eggplant Solanum torvum in an Hrp-dependent manner. An Agrobacterium-mediated transient expression system revealed that Rip36, a putative Zn-dependent protease effector of R. solanacearum, induced HR in S. torvum. A mutation in the putative Zn-binding motif (E149A) completely abolished the ability to induce HR. In agreement with this result, the RS1002-derived Δrip36 and rip36E149A mutants lost the ability to induce HR in S. torvum. An E149A mutation had no effect on the translocation of Rip36 into plant cells. These results indicate that Rip36 is an avirulent factor that induces HR in S. torvum and that a putative Zn-dependent protease motif is essential for this activity.

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記述言語：日本語   出版者・発行元：日本植物病理学会  

DOI： 10.3186/jjphytopath.80.146

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その他リンク： http://id.ndl.go.jp/bib/025814697

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Fungal viruses comprise two groups: a major group of five families with double-stranded RNA genomes and a minor group with positive-sense single-stranded (ss)RNA genomes. Although many fungal viruses have been identified, no negative-stranded (-)ssRNA mycoviruses have been reported. Here we present two lines of evidence suggesting the presence of (-)ssRNA viruses in filamentous fungi based on an exhaustive search using extant (-)ssRNA viruses as queries. This revealed (-)ssRNA virus L protein-like sequences in the genome of a phytopathogenic obligate ascomycete, Erysiphe pisi. A similar search for (-)ssRNA viruses in fungal transcriptome shotgun assembly libraries demonstrated that two independent libraries from Sclerotinia homoeocarpa, another phytopathogenic ascomycete, contained several sequences considered to correspond to the entire mononegavirus L gene and likely originating from an infecting (-)ssRNA virus. These results provide strong evidence for both ancient and extant (-)ssRNA virus infections in fungi. © 2012 Elsevier Inc.

DOI： 10.1016/j.virol.2012.10.002

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER JAPAN KK  

When an elicitor is applied to plants to induce resistance, one of the first detectable events is the efflux of ions from the treated tissue. Here we are the first to demonstrate that an elicitor from Mycosphaerella pinodes evokes leakage of Na+ and K+ ions from isolated cell walls of pea and cowpea in vitro, as observed for epicotyl tissues. Pharmacological experiments showed that this elicitor-stimulated leakage was sensitive to vanadate and N-(3-methylphenyl)biphenyl-4-sulfonamide (NGXT-191), that inhibit a cell wall-associated ATPase (apyrase). Vanadate or NGXT-191 suppressed elicitor-induced superoxide generation and expression of defense genes in vivo. On the basis of these results, we assume that the leakage of these ions, probably associated with an ATP-dependent process(es) in the cell wall, is likely associated with induced defenses of pea and cowpea.

DOI： 10.1007/s10327-012-0418-2

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Triterpenoid saponins are sugar-modified triterpene derivatives. Cereals and other grasses are generally deficient in these secondary metabolites with the exception of oat. Oat accumulates antimicrobial triterpenoid saponins in its roots. These oat-root-derived compounds, called avenacins, confer broad-spectrum resistance to soil-borne pathogens. Here, we tested the effect of avenacins on the development of infection structures of fungal pathogens Blumeria graminis f. sp. hordei and Bipolaris oryzae and Magnaporthe oryzae. We show that avenacins are able to inhibit the infection process of these phytopathogens on plant hosts. © 2012 The Phytopathological Society of Japan and Springer Japan.

DOI： 10.1007/s10327-012-0412-8

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記述言語：英語  

DOI： 10.1007/s10327-012-0405-7

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記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）   出版者・発行元：岡山大学農学部  

A plant growth-promoting fungus, Talaromyces wortmannii strain FS2 was isolated from an agricultural field at Okayama Pref. FS2 enhanced seed germination, root elongation and leaf growth of Brassica rapa var perviridis (Komatsuna). Such plant growth-promoting effect was observed in the same sealed chamber where FS2 was cultured on PDA medium separated from seedlings, suggesting effective volatile compound(s). GC‒MS analysis showed that FS2 emitted at least seven terpenoids, of which a volatile was identified as β‒caryophyllene. β‒caryophyllene alone promoted the growth of cucumber, Nicotiana benthamiana and barley. Furthermore β‒caryophyllene increased the yield of cucumber fruits. Interestingly, we found that β‒caryophyllene conditioned these plants to be resistant to respective diseases caused by Colletotrichum orbiculare, Botrytis cinerea or Blumeria graminis f. sp hordei. The findings indicate that β‒caryophyllene has desirable dual features and therefore, it is available to cultivation of many crops.
岡山県総社市の圃場から分離した植物生育促進菌Talaromyces wortmannii FS2が生産するβ-caryophylleneは，コマツナ（アブラナ科）のみならず，キュウリ（ウリ科），タバコ（ナス科）およびオオムギ（イネ科）など広汎な植物に対して，生育促進作用および耐病性増進作用を示したことから，有用な農業資材として利用可能であるものと考察した．

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記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）   出版者・発行元：岡山大学農学部  

A plant growth-promoting fungus was isolated from an agricultural field in Okayama Prefecture, Japan. The strain FS2, which enhanced seed germination, root elongation and leaf growth of Brassica rapa var. perviridis, was identified as Talaromyces wortmannii based on ITS1 sequence and its morphology.
本研究では，実際の生産圃場から植物生育促進菌（PGPF）の探索を試み，コマツナの生育を促進するFS2株を分離した．FS2株の形態観察並びにのITS1領域の系統樹解析から本菌をTalaromyces wortmanniiと同定した．

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Type IV pilin (PilA) is a major constituent of pilus and is required for bacterial biofilm formation, surface motility and virulence. It is known that mature PilA is produced by cleavage of the short leader sequence of the pilin precursor, followed by methylation of N-terminal phenylalanine. The molecular mass of the PilA mature protein from the tobacco bacterial pathogen Pseudomonas syringae pv. tabaci 6605 (Pta 6605) has been predicted to be 12 329 Da from its deduced amino acid sequence. Previously, we have detected PilA as an approximately 13-kDa protein by immunoblot analysis with anti-PilA-specific antibody. In addition, we found the putative oligosaccharide-transferase gene tfpO downstream of pilA. These findings suggest that PilA in Pta 6605 is glycosylated. The defective mutant of tfpO (ΔtfpO) shows reductions in pilin molecular mass, surface motility and virulence towards host tobacco plants. Thus, pilin glycan plays important roles in bacterial motility and virulence. The genetic region around pilA was compared among P. syringae pathovars. The tfpO gene exists in some strains of pathovars tabaci, syringae, lachrymans, mori, actinidiae, maculicola and P. savastanoi pv. savastanoi. However, some strains of pathovars tabaci, syringae, glycinea, tomato, aesculi and oryzae do not possess tfpO, and the existence of tfpO is independent of the classification of pathovars/strains in P. syringae. Interestingly, the PilA amino acid sequences in tfpO-possessing strains show higher homology with each other than with tfpO-nonpossessing strains. These results suggest that tfpO and pilA might co-evolve in certain specific bacterial strains.

DOI： 10.1111/j.1364-3703.2012.00789.x

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER JAPAN KK  

An endophytic actinomycete, Streptomyces padanus AOK30, is capable of protecting mountain laurel against infection by Pestalotiopsis sydowiana, a causal agent of Pestalotia disease, when applied to the seedling of the plant. In this study, suppression subtractive hybridization was used to identify genes differentially expressed in seedlings of mountain laurel after application of S. padanus AOK30. Subsequent dot hybridization with independent RNA from S. padanus-colonized and control plants identified nonredundant 180 cDNAs involving 71 and 109 clones, which were up- and downregulated after inoculation with the bacteria, respectively. Comparison of the sequences with databases revealed that a number of transcripts encoding proteins or enzymes that function directly in defense or stress response and regulatory proteins were regulated differentially in the seedlings with colonizing S. padanus AOK30. Semi-quantitative RT-PCR analysis for the selected genes demonstrated that inoculation of mountain laurel seedlings with S. padanus AOK30 increased expression of defense-related genes as well as distinct classes of glutathione S-transferase, although endochitinases were exclusively suppressed. These results clearly indicate that the S. padanus-colonizing seedlings likely initiate or prime plant defense responses toward pathogen infection. Selected genes were also differentially expressed in S. padanus-colonized seedlings, compared to those solely challenged with the fungal pathogen P. sydowiana. This approach will assist in efforts not only to understand the molecular basis of the enhanced tolerance and/or enhanced disease resistance of mountain laurel, but also to define a core set of genes during colonization or association with S. padanus AOK30.

DOI： 10.1007/s10327-012-0396-4

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER HEIDELBERG  

To investigate the mechanism of activation of the genes for resistance-nodulation-division (RND) family members MexE, MexF, and OprN for multidrug resistance (MDR), we mutagenized aefR and mexT, the potential regulators of mexEF/oprN transcription in Pseudomonas syringae pv. tabaci 6605 (Pta 6605). AefR is a member of the TetR transcription factors, and is known to be required for production of the quorum-sensing molecules, acyl homoserine lactones (AHL), in P. syringae. Furthermore, we found that AHL-synthesis-defective mutant strains in Pta 6605 showed enhanced expression of mexEF/oprN, and were highly tolerant to antimicrobial compounds such as chloramphenicol. MexT is a LysR-type transcription factor and is known to positively regulate transcription of mexEF/oprN in Pseudomonas aeruginosa. The a dagger aefR mutant reduced the amount of growth in in vitro culture, caused the loss of AHL production, reduced the swarming motility, virulence and expression of psyI (AHL synthase) and psyR (AHL transcriptional regulator), and enhanced mexEF/oprN expression and tolerance to chloramphenicol, whereas the a dagger mexT mutant retained the ability to produce AHL and did not show remarkable changes in in vitro growth, tolerance to antimicrobial compounds or virulence. Furthermore, unlike P. aeruginosa, the expression of mexEF/oprN is independent of MexT. These results indicate that (1) AefR is a regulator for the quorum-sensing system and MDR, and is required for swarming motility and virulence toward the host tobacco plant, and (2) MexT is not involved in the expression of mexEF/oprN in this bacterium.

DOI： 10.1007/s00438-012-0693-9

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記述言語：英語  

DOI： 10.1007/s10327-012-0399-1

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER TOKYO  

A plant-growth-promoting fungus (PGPF), Talaromyces sp. was isolated from an agricultural field in southwestern Japan. We found that this fungus emitted several terpenoid-like volatiles including beta-caryophyllene. Then we investigated the effect of beta-caryophyllene on promoting the growth and inducing resistance of Brassica campestris L. var. perviridis. The compound significantly enhanced the growth of seedlings and their resistance to Colletotrichum higginsianum. On the basis of these results, we discuss the role of beta-caryophyllene in the activities of PGPF.

DOI： 10.1007/s10327-011-0340-z

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

The HrpZ harpin of Pseudomonas syringae is known to induce a hypersensitive response (HR) in some plants. In P. syringae pv. tabaci (Pta), the harpin gene hrpZ has been spontaneously disrupted by an internal deletion in its open reading frame and a frame shift. The loss of the ability of the recombinant harpin polypeptide of Pta to induce HR despite the high sensitivity of tobacco plants to harpin led us to investigate the meaning of the disrupted hrpZ gene in the virulence of Pta 6605. The hrpZ gene from P. syringae pv. pisi was introduced into wild-type (WT) Pta. The hrpZ-complemented Pta secreted harpin into the culture medium, but failed to cause disease symptoms by both infiltration and spray inoculation. Inoculation with the hrpZ-complemented Pta induced defence responses in tobacco plants, whereas the defence responses of tobacco plants were not prominent on inoculation with WT Pta. These results indicate that an ancestor of Pta might have disrupted hrpZ by an internal deletion to evade plant defences and confer the ability to cause disease in tobacco plants.

DOI： 10.1111/J.1364-3703.2011.00705.X

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER HEIDELBERG  

The motor proteins around the flagellar basal body consist of two cytoplasmic membrane proteins, MotA and MotB, and function as a complex that acts as the stator to generate the torque that drives rotation. Genome analysis of several Pseudomonas syringae pathovars revealed that there are two sets of genes encoding motor proteins: motAB and motCD. Deduced amino acid sequences for MotA/B and MotC/D showed homologies to the H(+)-driven stator from Escherichia coli and Na(+)-driven stator from Vibrio alginolyticus, respectively. However, the swimming motility of P. syringae pv. tabaci (Pta) 6605 was inhibited by the protonophore carbonyl cyanide m-chlorophenylhydrazone but not by the sodium stator-specific inhibitor phenamil. To identify a gene encoding the stator protein required for motility, a dagger motAB, a dagger motCD, and a dagger motABCD mutants were generated. The a dagger motCD mutant had remarkably reduced and the a dagger motABCD mutant completely abolished swimming motilities, whereas the a dagger motAB mutant retained some degree of these abilities. The a dagger motCD and a dagger motABCD mutants did not produce N-acyl-homoserine lactones (AHLs), quorum-sensing molecules in this pathogen, and remarkably reduced the ability to cause disease in host tobacco leaves, as we previously observed in the a dagger fliC mutant strain. These results strongly indicate that both stator pairs in Pta 6605 are proton-dependent and that MotCD is important for not only flagellar motility but also for production of AHLs and the ability to cause disease in host plants.

DOI： 10.1007/s00438-010-0594-8

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1128/JB.00689-09

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD  

Pseudomonas syringae pv. tabaci (Pta) possesses a genetic region composed of two open reading frames (ORFs), fgt1 and fgt2, that are involved in glycosylation of flagellin. The deletion mutant Delta fgt1 produced non-glycosylated flagellin, and exhibited reduced ability to cause disease in the host tobacco plant. Flagellin is known to induce plant defense responses, and the recognition of flagellin by Arabidopsis thaliana is mediated by a conserved N-terminal region, flg22, in flagellin and a leucine-rich repeat domain in the FLS2 receptor. Because flg22 localizes inside the flagellum, polymerized flagellum needs to be dissociated to be recognized. Therefore, the effect of glycosylation on flagella stability was investigated. The polymerized flagella from glycosylated flagellins were more resistant to heat treatment than those from non-glycosylated flagellins, suggesting that the glycosylation of flagellin contributes to the structural stability of flagella and prevents exposure of the flg22 region. Polymerized flagella from Pta Delta fgt1 flagellin and depolymerized and glycosylated flagellin from Pta wild type induced cell death and callose deposition, and inhibited seedling growth in tobacco more effectively, whereas polymerized flagella from Pta wild-type flagellin caused a low level of these responses. These results suggest Pta might have evolved the flagellin glycosylation system to evade detection and defense response of a host by increasing flagella stability and suppressing their dissociation. (C) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.pmpp.2009.08.001

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER PHYTOPATHOLOGICAL SOC  

Flagellin proteins derived from Pseudomonas syringae pv. tabaci 6605 and flg22(Pa) (QRLSTGSRINSAKDDAAGLQIA), one of the microbe-associated molecular patterns (MAMP) in bacterial flagellin, induce cell death and growth inhibition in Arabidopsis thaliana. To examine the importance of aspartic acid (D) at position 43 from the N-terminus of a flagellin in its elicitor activity, D43 was replaced with valine (V) and alanine (A) in P. syringae pv. tabaci flagellin and flg22(Pta). The abilities of flagellins from P syringae pv. tabaci D43V and D43A to induce cell death and growth inhibition were reduced, whereas the abilities of flg22(Pta)D43V and flg22(Pta)D43A were abolished. These results indicate that D43 is important for elicitor activity in P. syringae pv. tabaci. When tobacco plants were inoculated with each bacterium by the spray method, both P. syringae pv. tabaci D43V and D43A mutants had remarkably reduced ability to cause disease symptoms. Both mutants had reduced or no swimming and swarming motilities and adhesion ability. In P. syringae pv. tabaci D43V, little flagellin protein was detected and few flagella were observed by electron microscopy. These results indicate that mutant flagella are unstable and that flagellar motility is impaired. Thus, the amino acid residue required for MAMP activity is important for the intrinsic flagellar function.

DOI： 10.1094/MPMI-21-9-1165

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER  

Pseudomonas syringae pv. tabaci 6605 causes wildfire disease on host tobacco plants. To investigate the regulatory mechanism of the expression of virulence, Gac two-Component system-defective mutants, Delta gacA and Delta gacS, and a double mutant, Delta gacA Delta gacS, were generated. These mutants produced smaller amounts of N-acyl homoserine lactones required for quorum sensing, had lost swarming motility, and had reduced expression of virulence-related hrp genes and the algT gene required for exopolysaccharide production. The ability of the mutants to cause disease symptoms in their host tobacco plant was remarkably reduced, while they retained the ability to induce hypersensitive reaction (HR) in the nonhost plants. These results indicated that the Gac two-component system of P. syringae pv. tabaci 6605 is indispensable for virulence on the host plant, but not for HR induction in the nonhost plants.

DOI： 10.1007/s00438-007-0309-y

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：OXFORD UNIV PRESS  

The plastid, which originated from the endosymbiosis of a cyanobacterium, contains its own plastid DNA (ptDNA) that exhibits a unique mode of inheritance. Approximately 80 of angiosperms show maternal inheritance, whereas the remainder exhibit biparental inheritance of ptDNA. Here we studied ptDNA inheritance in the model legume, Medicago truncatula. Cytological analysis of mature pollen with DNA-specific fluorescent dyes suggested that M. truncatula is one of the few model plants potentially showing biparental inheritance of ptDNA. We further examined pollen by electron microscopy and revealed that the generative cell (a mother of sperm cells) indeed has many DNA-containing plastids. To confirm biparental inheritance genetically, we crossed two ecotypes (Jemalong A17 and A20), and the transmission mode of ptDNA was investigated by a PCR-assisted polymorphism. Consistent with the cytological observations, the majority of F-1 plants possessed ptDNAs from both parents. Interestingly, cotyledons of F-1 plants tended to retain a biparental ptDNA population, while later emergent leaves tended to be uniparental with either one of the parental plastid genotypes. Biparental transmission was obvious in the F-2 population, in which all plants showed homoplasmy with either a paternal or a maternal plastid genotype. Collectively, these data demonstrated that M. truncatula is biparental for ptDNA transmission and thus can be an excellent model to study plastid genetics in angiosperms.

DOI： 10.1093/pcp/pcm170

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BLACKWELL PUBLISHING  

Non-host resistance is the most general form of disease resistance in plants because it is effective against most phytopathogens. The importance of hypersensitive responses (HRs) in non-host resistance of Nicotiana species to the oomycete Phytophthora is clear. INF1 elicitin, an elicitor obtained from the late-blight pathogen Phytophthora infestans, is sufficient to induce a typical HR in Nicotiana species. The molecular mechanisms that underlie the non-host resistance component of plant defence responses have been investigated using differential-display polymerase chain reaction (PCR) in a model HR system between INF1 elicitin and tobacco BY-2 cells. Differential-display PCR has revealed that Cdc27B is down-regulated in tobacco BY- 2 cells after treatment with INF1 elicitin. Cdc27B is one of 13 essential components of the anaphase- promoting complex or cyclosome ( APC/ C)-type E3 ubiquitin ligase complex in yeast. This APC/C-type E3 ubiquitin ligase complex regulates G2-to-M phase transition of the cell cycle by proteolytic degradation. In this study, we investigated the roles of this gene, NbCdc27B, in plant defence responses using virus-induced gene silencing. Suppression of NbCdc27B in Nicotiana benthamiana plants induced defence responses and a gain of resistance to Colletotrichum lagenarium fungus. Elicitin-induced hypersensitive cell death (HCD) was inhibited mildly in plants silenced with tobacco rattle virus:: Cdc27B. Cdc27B could manage the signalling pathways of plant defence responses as a negative regulator without HCD.

DOI： 10.1111/J.1364-3703.2007.00397.X

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The inhibition of elicitor-induced plant defense responses by the protein kinase inhibitors K252a and staurosporine indicates that defense responses require protein phosphorylation. We isolated a cDNA clone encoding Nicotiana tabacum lectin-like receptor protein kinase 1 (NtlecRK1), an elicitor-responsive gene
in tobacco bright yellow (BY-2) cells by a differential display method. NtlecRK forms a gene family with at least three members in tobacco. All three NtlecRK genes potentially encode the N-terminal legume lectin domain, transmembrane domain and C-terminal Ser/Thr-type protein kinase domain. Green fluorescent protein (GFP) fusion showed that the NtlecRK1 protein was located on the plasma membrane. In addition, NtlecRK1 and 3 were responsive to INF1 elicitin and the bacterial elicitor harpin. These results indicate that NtlecRKs are membrane-located protein kinases that are induced during defense responses in BY-2 cells. © 2007 Informa UK Ltd.

DOI： 10.1080/10425170601060905

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10327-005-0267-3

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記述言語：英語  

Mycosphaerella blight, caused by Mycosphaerella pinodes, is one of the major diseases of cultivated pea (Pisum sativum L.). To isolate the genes that are up- and down-regulated during spore germination, suppression subtraction hybridization (SSH) was performed between ungerminated and germinated spores. The 232 and 128 clones from forward and reverse libraries, respectively, were collected, sequenced, and analyzed with a BLASTX homology search. About 95% of the 32 selected clones were expressed during spore germination on a paper sheet and during infection of pea leaves. We discuss the applicability of the SSH libraries for analyzing M. pinodes genes involved in the early stage of infection. © The Phytopathological Society of Japan and Springer-Verlag 2005.

DOI： 10.1007/s10327-005-0185-4

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

A new method to discriminate between tobamoviruses and their pathotypes that infect green pepper (Capsicum annuum L.) was developed using reverse transcription-polymerase chain reaction (RT-PCR). The P0 pathotype (Tobacco mosaic virus, Tomato mosaic virus, and Tobacco mild green mosaic virus) and the P1 pathotype (Paprika mild mottle virus) were distinguished by RT-PCR using primers specific to each pathotype. However, the P1,2 and P1,2,3 pathotypes of Pepper mild mottle virus (PMMoV) could not be distinguished from each other using this procedure. The P1,2 and P1,2,3 pathotypes were differentiated by RT-nested PCR, in which a DNA fragment was first produced by RT-PCR using primers containing conserved sequences of PMMoV. The product was then used as the DNA template in a second PCR using primers specific to each pathotype. An immunocapture (IC) RT-PCR method was developed based on results from this study, which facilitated detection of tobamoviruses in pepper plants, seeds, and field soils and allowed the identification of their pathotypes. © The Phytopathological Society of Japan and Springer-Verlag 2005.

DOI： 10.1007/s10327-004-0161-4

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記述言語：英語  

DOI： 10.1007/s10327-005-0197-0

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記述言語：英語  

We transformed Colletotrichum trifolii, the causal agent of alfalfa anthracnose, using Agrobacterium tumefaciens as a new tool for random insertional mutagenesis. Fungal spores of C. trifolii were transformed with T-DNA including the hygromycin phosphotransferase gene (hph). Southern analysis showed that every randomly selected transformant had a unique hybridization pattern of T-DNA, suggesting that the T-DNA was randomly integrated into the fungal genome. More significantly, about 75% of transformants had a single copy of the T-DNA. The results demonstrate that insertional mutagenesis via A. tumefaciens is a useful tool for studying the function of C. trifolii genes.

DOI： 10.1007/s10327-003-0099-y

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER-VERLAG  

Recently, we observed that expression of a pea gene (S64) encoding an oxophytodienoic acid reductase (OPR) was induced by a suppressor of pea defense responses, secreted by the pea pathogen Mycosphaerella pinodes. Because it is known that OPRs are usually encoded by families of homologous genes, we screened for genomic and cDNA clones encoding members of this putative OPR family in pea. We isolated five members of the OPR gene family from a pea genomic DNA library, and amplified six cDNA clones, including S64, by RT-PCR (reverse transcriptase-PCR). Sequencing analysis revealed that S64 corresponds to PsOPR2, and the amino acid sequences of the predicted products of the six OPR-like genes shared more than 80% identity with each other. Based on their sequence similarity, all these OPR-like genes code for OPRs of subgroup I, i.e., enzymes which are not required for jasmonic acid biosynthesis. However, the genes varied in their exon/intron organization and in their promoter sequences. To investigate the expression of each individual OPR-like gene, RT-PCR was performed using gene-specific primers. The results indicated that the OPR-like gene most strongly induced by the inoculation of pea plants with a compatible pathogen and by treatment with the suppressor from M. pinodes was PsOPR2. Furthermore, the ability of the six recombinant OPR-like proteins to reduce a model substrate, 2-cyclohexen-1-one (2-CyHE), was investigated. The results indicated that PsOPR1, 4 and 6 display robust activity, and PsOPR2 has a most remarkable ability to reduce 2-CyHE, whereas PsOPR3 has little and PsOPR5 does not reduce this compound. Thus, the six OPR-like proteins can be classified into four types. Interestingly, the gene structures, expression profiles, and enzymatic activities used to classify each member of the pea OPR-like gene family are clearly correlated, indicating that each member of this OPR-like family has a distinct function.

DOI： 10.1007/s00438-003-0948-6

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記述言語：英語   出版者・発行元：The Genetics Society of Japan  

Here we report the genomic structure including the promoter sequence and coding region of NtPDR1 (Nicotiana tabacum Pleiotropic Drug Resistance 1), which is an elicitor-responsive gene encoding an ATP binding cassette (ABC) transporter that might be involved in the defense response in tobacco, as we reported recently. The NtPDR1 gene consists of 20 exons and 19 introns. Among the introns, the first and fifth are much larger than the others and harbor typical miniature inverted-repeat transposable elements (MITEs). One of the MITE elements in the first intron, termed NtToya1, belongs to the Toya family that was recently described in rice, while the other element in the fifth intron, termed NtStowaway101, shows high homology with the Stowaway elements of the IS630-Tc1-mariner family. Many of the genes we found to harbor Toya and Stowaway elements in Nicotiana species by BLAST search are also involved in stress responses or plant-pathogen interactions. The existence of putative cis-elements (a GCC box, three W boxes, and several JA-responsive elements) in the promoter region supports our previous finding that this gene is strongly inducible by elicitation and methyljasmonate, and that this ABC transporter might be essential for plant defense responses. Furthermore, Southern blot analysis and PCR amplification of the introns harboring the MITE-like elements from genomic DNA of three Nicotiana species suggests that NtPDR1 originated from N. sylvestris.<br>

DOI： 10.1266/ggs.78.409

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その他リンク： https://jlc.jst.go.jp/DN/JALC/00235071103?from=CiNii

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1128/JB.22.6658-6665.2003

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER-VERLAG  

To investigate the role of flagella and monomer flagellin in the interaction between Pseudomonas syringae pv. tabaci and plants, non-polar fliC and fliD mutants were produced. The ORFs for fliC and fliD are deleted in the DeltafliC and DeltafliD mutants, respectively. Both mutants lost all flagella and were non-motile. The DeltafliC mutant did not produce flagellin, whereas the DeltafliD mutant, which lacks the HAP2 protein, secreted large amounts of monomer flagellin into the culture medium. Inoculation of non-host tomato leaves with wild-type P. syringae pv. tabaci or the DeltafliD mutant induced a hypersensitive reaction (HR), whereas the Deltaflid mutant propagated and caused characteristic symptom-like changes. In tomato cells in suspension culture, wild-type P. syringae pv. tabaci induced slight, visible HR-like changes. The DeltafliC mutant did not induce HR, but the DeltafliD mutant induced a remarkably strong HR. Expression of the hsr203J gene was rapidly and strongly induced by inoculation with the DeltafliD mutant, compared to inoculation with wild-type P. syringae pv. tabaci. Furthermore, introduction of the fliC gene into the DeltafliC mutant restored motility and HR-inducing ability in tomato. These results, together with our previous study, suggest that the flagellin monomer of pv. tabaci acts as a strong elicitor to induce HR-associated cell death in non-host tomato cells.

DOI： 10.1007/s00438-003-0817-3

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記述言語：英語   出版者・発行元：Japanese Society for Plant Cell and Molecular Biology  

A cDNA clone, designated PsDof1, encoding a novel member of the Dof DNA-binding protein family was isolated from pea. Random-binding-site selection and gel retardation experiments showed that the GST-PsDof1 recombinant protein bound to specific DNA sequences with an AAAG core. A metal-chelating agent, 1, 10-phenanthroline, abolished binding of GST-PsDof1 to DNA, but the addition of Zn²⁺ restored it, indicating that zinc ions are required for its DNA-binding activity. Interestingly, there are possible sites for binding PsDof1 in its promoter sequence. Indeed, GST-PsDof1 binds to the AAAG-containing promoter sequence of the PsDof1 gene with higher affinity. These results suggest that PsDof1 is a novel transcription factor that is involved in its own transcriptional regulation.

DOI： 10.5511/plantbiotechnology.19.251

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その他リンク： https://jlc.jst.go.jp/DN/JALC/00161151771?from=CiNii

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER SCIENCE BV  

We isolated an INF1 elicitin-inducible cDNA encoding a pleiotropic drug resistance (PDR)-type ATP-binding cassette (A-BC) transporter homolog (NtPDR1) in suspension-cultured tobacco Bright Yellow-2 (BY-2) cells by application of differential display PCR. The NtPDR1 (Nicotiana tabacum PDR protein 1) gene also encodes a 162 kDa protein that includes two putative hydrophilic domains containing the ABC signature motif and two putative hydrophobic domains. Expression of the NtPDR1 gene was rapidly and strongly activated by treatment of BY-2 cells with INF1 elicitin. Further, treatment of BY-2 cells with flagellin, a bacterial proteinaceous hypersensitive reaction elicitor, or yeast extract, a general elicitor, also induced NtPDR1 gene expression. These results indicate that NtPDR1 may be involved in the general defense response in tobacco. This is the first report that microbial elicitors induce the expression of a plant ABC transporter gene. (C) 2002 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：GAUTHIER-VILLARS/EDITIONS ELSEVIER  

Expression of genes (PSPAL) encoding phenylalanine ammonia-lyase from pea (Pisum sativum L.) is regulated in response to various environmental stimuli and during plant development. We examined the cis-regulatory elements in PSPAL1 promoter for organ-specific expression by determining the sequences specifically associated with nuclear proteins on its promoter in each pea organ. In vivo dimethyl sulfate (DMS) footprinting analysis showed putative protein bindings on AC-rich sequences including Box-I in particular in roots and stems in which PSPAL mRNA were highly accumulated. The potential role of the AC-rich element was investigated by fusing PSPAL1 promoter with Box-I deleted to the reporter gene P-glucuronidase (GUS) and transforming the construct into tobacco plants (Nicotiana tabacum). GUS activity controlled under this Box-I deletion promoter was significantly reduced in roots and leaves, whereas drastically increased in stems as compared with the activity of wild-type PSPALI promoter. Histochemical GUS staining indicated the activity was elevated in vascular tissues of stem by deleting Box-I. These results suggest that Box-I in PSPALI contributes to a positive regulation in root and leaf, but might also function as a negative regulator in stem, especially in xylem tissue. (C) 2001 Editions scientifiques et medicales Elsevier SAS.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER SCI IRELAND LTD  

Clone E86 was isolated as cDNA for elicitor-inducible gene From pea epicotyls by differential screening. The deduced amino acid sequence of E86 showed high homology to hypersensitivity-related protein hsr203J in tobacco and also showed significant homologies to the Ser-active hydrolases, such as mammalian hormone-sensitive lipases, bacterial lipases and esterases. E86 polypeptide possesses consensus amino acid sequence motifs (His-Gly) and (Gly-X-Ser-X-Gly) conserved in lipases and esterases and showed esterase degradation of p-nitrophenyl butyrate. Northern blot analysis revealed that the E86-transcript is abundant in roots and stems and was induced by fungal elicitor in pea epicotyls. However, elicitor-induced accumulation of E86 mRNA was significantly inhibited by the fungal suppressor. Furthermore the expression of the genes encoding E86 and phenylalanine ammonia-lyase was induced within 1 h after the inoculation of a nonpathogen. but it was delayed for 5 h by the inoculation of a compatible pathogen. These results suggest that the elicitor-induced Ser-active hydrolase derived from E86 gene might be related to the plant defense responses. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：AMER PHYTOPATHOLOGICAL SOC  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：AMER PHYTOPATHOLOGICAL SOC  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BLACKWELL SCIENCE LTD  

We characterized pharmacologically the hypersensitive cell death of tobacco BY-2 cells that followed treatments with Escherichia coli preparations of INF1, the major secreted elicitin of the late blight pathogen Phytophthora infestans. INF1 elicitin treatments resulted in fragmentation and 180 bp laddering of tobacco DNA as early as 3 h post-treatment. INF1 elicitin also induced rapid accumulation of H2O2 typical of oxidative burst, and the expression of defense genes such as phenylalanine ammonia-lyase (PAL) gene at 1 h and 3 h after elicitin treatment, respectively. To investigate the involvement of the oxidative burst and/or the expression of defense genes in the signal transduction pathways leading to hypersensitive cell death, we analyzed the effect of several chemical inhibitors of signal transduction pathways on the various responses. The results indicated that (a) the cell death required serine proteases, Ca2+ and protein kinases, (b) the oxidative burst was involved in Ca2+ and protein kinase mediated pathways, but elicitin-induced AOS was neither necessary nor sufficient for cell death and PAL gene expression, and (c) the signaling pathway of PAL gene expression required protein kinases. These results suggest that the three signal transduction pathways leading to cell death, oxidative burst and expression of defense genes branch in the early stages that follow elicitin recognition by tobacco cells.

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記述言語：日本語   出版者・発行元：日本植物病理学会  

DOI： 10.3186/jjphytopath.65.247

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：SPRINGER  

The mechanism of plant host-parasite specificity is one of the most intriguing issues of contemporary plant biology. We recently found that a fungal elicitor stimulated cell wall functions such as ATP-hydrolyzing and superoxide generating activities. Furthermore, the suppressor from Mycosphaerella pinodes inhibited these activities in vitro in a strictly species-specific manner. The cell wall-bound ATPase, which is different from that of the plasma membrane in several properties, was associated with cell wall-bound peroxidase(s). In response to the elicitor, the isolated cell walls are able to produce an infection-inhibitor that may be dependent upon the superoxide generating system. On the other baud, the suppressor inhibited such production in pea cell walls and induced it in nonhost's cell walls. Thus, the effects of both fungal signals on isolated cell walls coincide with those on plant tissues. Ln this treatise, we discuss the importance of the cell wall, which is plant-specific acid the most exterior organelle, in determining host-parasite specificity.

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掲載種別：研究論文（学術雑誌）   出版者・発行元：The Phytopathological Society of Japan  

DOI： 10.3186/jjphytopath.64.519

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：JAPANESE SOC PLANT PHYSIOLOGISTS  

The glycopeptide elicitor from a pea pathogen, Mycosphaerella pinodes, induced rapid alkalinization and increases in levels of Na+ and K+ ions in the extracellular solution upon contact with pea and cowpea tissues, The presence of monensin, nigericin, lidocaine, quinidine or phenytoin together with the elicitor markedly inhibited these changes, whereas the presence of valinomycin, gramicidin D, tetraethylammonium, CsCl and aminopyridine did not. The production of phytoalexins in pea and cowpea tissues was also strongly inhibited by the simultaneous presence of the former reagents but not of the latter reagents. Inhibitory effects on the production of phytoalexins were diminished when monensin, nigericin or a Na+-channel blocker was applied 3 h after the start of treatment with elicitor, Furthermore, orthovanadate and neomycin, which suppress defense responses in both tissues, also inhibited the above mentioned changes. By contrast, the species-specific suppressor from M. pinodes inhibited the elicitor-induced release of Na+ and K+ ions from pea tissues, but, conversely, by itself it elicited either the defense response or the release of Na+ and K+ ions from cowpea tissues. The results indicate that these ion-related changes, in particular the efflux of Na+ and K+ ions, might be closely associated with the signal transduction system for defense responses at the tissue level.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：JAPANESE SOC PLANT PHYSIOLOGISTS  

It was found that NTPases were bound to cell walls of pea and cowpea. The suppressor in pycnospore germination fluid of a pea pathogen, Mycosphaerella pinodes, inhibited the ATPase activity in the fraction, which was solubilized from pea cell wall with 0.5% Triton X-100, in a dose-dependent manner, but rather enhanced that from cowpea cell wall even at the concentration of 1 mu g ml(-1). Inhibition by the suppressor of pea cell wall-bound ATPase was a mixed type of competitive and noncompetitive. Triton X-100 PAGE and active staining of ATPase indicated that both Triton X-100 solubilized fractions contained plural molecules that hydrolyze ATP. The M(r)s of cell wall-bound ATPases seem to be considerably different from those of plasma membranes, and the number of cell wall-bound ATPase molecules were different between pea and cowpea. The electroeluted fractions corresponding to the bands of active-stained ATPases were also able to hydrolyze NTP and PPi. The respective electroeluted ATPases also showed the species-specific response to the suppressor. These results may confirm our previous concept that putative receptors for the suppressor might tightly bind to cell wall-bound ATPase or that the ATPase might be the receptor itself.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：AMER PHYTOPATHOLOGICAL SOC  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACADEMIC PRESS LTD  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：JAPANESE SOC PLANT PHYSIOLOGISTS  

Effects of the elicitor and/or suppressor from Mycosphaerella pinodes on polyphosphoinositide metabolism (PI metabolism) in pea were examined both in vivo and in vitro. The elicitor induced a rapid and biphasic increase in levels of phosphatidylinositol-4,5-bisphosphate (PtdInsP2) and inositol 1,4,5-trisphosphate (IP3) in epicotyl tissues that was apparent within 15 min. A transient increase in levels of PtdInsP2 and IP3 was detected immediately in elicitor-treated plasma membranes. However, the concomitant presence of suppressor with elicitor resulted in inhibition of these increases both in vivo and in vitro. These findings suggest that the elicitor rapidly activates phosphatidylinositol kinase, phosphatidylinositol-4-monophosphate kinase and phospholipase C, which are involved in PI metabolism, whereas the suppressor markedly inhibits these enzymes. Neomycin, a known inhibitor of phospholipase C, blocked the elicitor-induced accumulation both of IP3 and pisatin and it also induced local susceptibility in pea tissues that resembled that of the fungal suppressor. From these results, it appears that rapid changes in PI metabolism are indispensable in the signal transduction related to defense responses of pea plants.

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The effects of two suppressors of the defense reactions of host plants, which had been purified from the pea pathogen Mycosphaerella pinodes, as well as the effects of peptide moieties, on the ATPase activity in pea plasma membranes were examined in vitro. One of the suppressors, Supprescin B, inhibited the ATPase activity in a non-competitive manner, but the other suppressor, Supprescin A, did not. Supprescin A was observed to reduce the inhibitory effect of Supprescin B. A tripeptide, Ser-Ser-Gly, and a hexapeptide, Ser-Ser-Gly-Asp-Glu-Thr, which were the respective peptide moieties of Supprescin A and B, inhibited the ATPase activity in a competitive manner. Supprescin B and fragments of the hexapeptide, such as Asp-Glu-Thr and Gly- Asp-Glu, inhibited not only the ATPase activity but also the acid phosphatase activity of plasma membranes in vitro. These results indicate that the acidic amino-acid residues of the "Asp-Glu" moiety seem to act as inhibitors of the phosphatase activity. Thus, the peptide moiety of Supprescin B consists of at least two functional elements. © 1993. The Japanese Society of Plant Physiologists (JSPP).

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Oxford University Press  

Elicitor from Erysiphe pisi was incorporated into gel beads. Individual beads were placed on single cells from barley coleoptiles. The elicitor induced unusual cytoplasmic responses and temporary resistance to infection in coleoptile cells. The technique is applicable to assessment of elicitor activity at the single-cell level. © 1993. The Japanese Society of Plant Physiologists (JSPP).

DOI： 10.1093/oxfordjournals.pcp.a078483

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：OXFORD UNIV PRESS  

Effects of the elicitor and the suppressor from a pea pathogen, Mycosphaerella pinodes, on polyphosphoinositide metabolism in pea plasma membranes were examined in vitro. Lipid phosphorylation in the isolated pea plasma membrane was drastically stimulated by the elicitor, but markedly inhibited by the suppressor. A similar inhibitory effect was observed by the treatment with orthovanadate or K-252a that blocked pisatin production induced by the elicitor. Neomycin, an aminoglycoside antibiotic that interacts with the polyphosphoinositide metabolism, also affected the lipid phosphorylation in vitro and blocked the elicitor-induced accumulation of pisatin in vivo. These results suggest that rapid changes of polyphosphoinositide metabolism in pea plasma membranes is one of indispensable processes during the elicitation of defense responses.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：OXFORD UNIV PRESS  

Methyl jasmonate inhibited the harpin-induced defense responses such as cell death, H2O2 generation and gene expression encoding phenylalanine ammonia-lyase in tobacco suspension cultured BY-2 cells, These results suggest that MeJA may act as an endogenous suppressor for plant defense response including hypersensitive reaction.

DOI： 10.1093/pcp/pce056

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記述言語：英語   出版者・発行元：The Phytopathological Society of Japan  

Erysiphe graminisの分生胞子をオオムギ子葉鞘細胞に接種した(一次菌)。さらに同一細胞上に,別の子葉鞘上で発芽させた同菌の発芽胞子を細針で移植接種した(二次菌)。一次菌が二次菌よりも0∼5時間早く侵入を開始すると二次菌の吸器形成率は約80%,またこの時間差が6時間以上になると約93%に上昇した。針移植した対照区の吸器形成率は約63%であったので,一次菌の侵入によって誘導される受容性は同じ菌の二次菌にも有効であると結論された。この受容性は一次菌が吸器形成に成功した細胞でのみ誘導された。一細胞で誘導された受容性は,一次菌が侵入を開始してから少なくとも9.5時間までには隣接細胞に移行しなかった。

DOI： 10.3186/jjphytopath.57.57

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掲載種別：研究論文（学術雑誌）  

The influence of the duration of a direct stimulus by a non-pathogen to the enhancement of inaccessibility was examined using barley coleoptile cells and Erysiphe pisi. The degree of enhanced inaccessibility was evaluated with the rate of haustorium formation (penetration efficiency, PE) of E. graminis which attempted penetration of the same coleoptile cells as E. pisi. Partially dissected coleoptiles (coleoptiles A) were inoculated with E. pisi conidia. By observing the specimens every 15 min, the time of initiation of cytoplasmic aggregation in coleoptile cells below an individual E. pisi appressorium was recorded. At 0·5, 1·0 or 3·0 h after the initiation of cytoplasmic aggregation, germlings of E. pisi were removed by a micromanipulator. Germinating conidia of E. graminis which had been inoculated onto other coleoptiles were then transferred onto coleoptile A by micromanipulation so that they could attempt to penetrate the same cells in which E. pisi had induced a cytoplasmic aggregate. When E. pisi was removed 0·5 h after the initiation of cytoplasmic aggregation, the PE of E. graminis was reduced by 35·4%, suggesting that the inaccessibility was enhanced by the presence of E. pisi. When E. pisi was removed at 1·0 and 3·0 h, the subsequent PEs of E. graminis were 24·8% and 5·8%, respectively, indicating that the prolonged presence of E. pisi further enhanced the inaccessibility. The degree of enhanced inaccessibility was influenced by the size of coleoptile cells but not by the distances between penetration sites of the two fungi within the same cell and the time intervals of the initiation of cytoplasmic aggregation induced by both fungi. It is suggested that unknown mechanism(s) unrelated to papilla formation may be involved in the enhancement of inaccessibility. © 1989.

DOI： 10.1016/0885-5765(89)90092-1

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記述言語：英語  

DOI： 10.1016/j.micres.2019.04.004

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記述言語：日本語  

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記述言語：日本語   出版者・発行元：日本生物工学会  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：AMER PHYTOPATHOLOGICAL SOC  

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出版者・発行元：日本植物生理学会  

植物が生産するサポニンは配糖化トリテルペンであり、抗がん作用や植物病原菌に対する抗菌活性を持つものなど様々な誘導体が知られている。またエンバクを除く単子葉類では抗菌性サポニンは生合成されていない。そこで我々はイネに抗菌性サポニンの生産能を賦与することによる耐病性の獲得を最終目的として, イネのトリテルペン生合成経路遺伝子群の同定とその分子解析を試みている。これまでに1）イネのトリテルペン生合成経路遺伝子Oxidosqualene Cyclase 遺伝子はイネゲノム中に12個存在するが, トリテルペン生合成に関与する活性型の遺伝子は見い出せなかったこと，2）トリテルペン生合成経路の次のステップであるCYP51 sterol demethylase 遺伝子もまたイネゲノム中に12個存在し、1つがステロール生合成に、また他の1つがトリテルペン生合成に関与している可能性が見いだされたことを報告した。今回、我々はOxidosqualene Cyclase 遺伝子であるエンバクのβ-amyrin合成遺伝子 AsbAS1 を導入した形質転換体イネを作出し、このイネにおいて、トリテルペン中間体及びトリテルペンの代謝物分析をGC/MSを用いて行った。その結果、β-amyrinの蓄積は確認できたが、それ以降の代謝物の合成は認められなかった。

DOI： 10.14841/jspp.2011.0.0763.0

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記述言語：日本語  

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記述言語：日本語   出版者・発行元：岡山大学農学部  

In this report, an effect of FFC-ceramic (FFC-Japan Co. Ltd., Tsu) water on the process of infection by a pea fungal pathogen, Mycosphaerella pinodes was investigated. Energy dispersive X-ray analysis showed that both of the FFC-ceramic water and a common ceramic water contained mainly Ca and S elements, of which the relative atomic percentages were 53~56% and 44~45%, respectively. Lesion formation by pycnospores of M. pinodes on pea leaves was inhibited severely by the application with both ceramic waters at the 1/2~1/6 concentration of saturated solution. Cytological observation under microscope showed that germination, germ-tube elongation and penetration were severely inhibited by these ceramic waters. However, such inhibitory effect of FFC-ceramic water was superior to that of the common ceramic water. On ethanol-killed pea epidermal tissues, both FFC-ceramic water and the common ceramic water blocked the germination, germ-tube elongation and penetration by the pathogen, indicatingthe direct effect of both ceramic waters on the fungus. In this case, the inhibiting effect of FFC ceramic water was more intensive than the common ceramic water. CaSO(4) at a 1/2~1/4 concentration of saturated solution blocked penetration by the fungus on the killed epidermis of onion bulb but scarcely affected germination and germ-tube elongation. Based on these results, we discussed the role of FFC-ceramic water in disease tolerance of plants and its availability for cultivation.本研究は，FFCセラミックス(TM)（株 エフフシージャパン）の植物病原菌の発病抑制効果について調べたものである．FFCセラミック水は原液の1/2～1/6の濃度でエンドウ褐紋病菌の発病を顕著に抑制した．この原因を調べたところ，FFCセラミック水は，病原菌の発芽，発芽管伸長，侵入（貫入）を顕著に阻害することが判明した．FFCセラミック水中にはCa並びにS，O元素が多量に存在し，SEM観察の結果と合わせると，CaSO(4)が多量に含まれることが示唆された．そこで，CaSO(4)飽和液の1/2～1/4濃度で，病原菌に対する作用を調べた結果，発芽あるいは発芽管伸長はほとんど阻害されず，低率ながら侵入も観察された．これらの結果を総合して，FFCセラミック水やCaSO4の栽培場面での応用を考察した．

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その他リンク： http://agriknowledge.affrc.go.jp/RN/2010790178

記述言語：英語   出版者・発行元：岡山大學農學部  

本報は、（株）エフエフシー・ジャパンから販売されている土壌改質材FFCエース（TM）の作物の生長促進効果について、2006年11月から翌年6月、本学農学部内の実験圃場で実施された、オオムギの生育ならびに収量調査に関する試験結果をとりまとめたものである。実施圃場の砂土壌にFFCエースを所定量混和した区画を設け、オオムギの種子を播種した。なお、対照区は非導入土壌とした。定期的に行った生育調査の結果、FFCエースを導入した土壌では非導入の区画と比べて、生育初期における根の生育が良好となり、地上部における分けつ数の増加とともに穂の生長も旺盛となって、1穂当たりの収穫量（粒数）の著しい増加をもたらした。結果、FFCエース導入区における全収量は非導入区と比べて約1.7倍となった。また、それぞれから収穫したオオムギ粒に含まれる栄養価ならびに無機元素類の量には、FFCエースの導入、非導入によって大きな違いは認められず、導入の効果は収量に大きく反映された。事実、調査期間中に行った測定から、FFCエースを投入した土壌で生育するオオムギ葉は高いクロロフィル量を示しており、光合成が促進されているものと考えられた。実際、播種後4ヶ月目以降、光合成ならびに蒸散速度値を測定した結果、FFCエース導入区で生育したオオムギでは常に高い値を示した。また、FFCエースの導入によって強光条件下における水利用効率が促進された。本報告では、FFCエースの投与と空気中からの二酸化炭素の吸収量との関連について考察するとともに、併せて、FFCエースの土壌への導入によって作物の生育に必要な灌水量を大きく減らすことができる可能性についても言及したい。

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その他リンク： http://agriknowledge.affrc.go.jp/RN/2010790176

記述言語：英語  

DOI： 10.1007/s10327-009-0162-4

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出版者・発行元：日本植物生理学会  

植物が生産するサポニンは配糖化トリテルペンであり、抗がん作用や抗菌活性を持つものなど様々な誘導体が知られている。特にエンバクやトマト植物が生産する抗菌性サポニンはエンバク立枯病菌やトマト白星病菌の感染成否に深く関わっていることが知られている。またエンバクを除く単子葉類では抗菌性サポニンは生合成されていない。そこで我々はイネに抗菌性サポニンの生産能を賦与することによる新規な耐病性の獲得を最終目的として, イネのサポニン（トリテルペン）生合成経路遺伝子群の同定とその分子解析を試みている。これまでに1）イネの幼苗時のサポニン, トリテルペン様化合物およびその中間体はLC/MS及びGC/MS解析によりいずれも見いだされなかったこと，2）イネのトリテルペン生合成経路遺伝子Oxidosqualene Cyclase 遺伝子はイネゲノム中に12個存在するが, トリテルペン生合成に関与する活性型遺伝子は見い出せなかったことを報告した。今回我々はトリテルペン生合成経路の次のステップであるCYP51 sterol demethylase 遺伝子について分子解析を行った。本遺伝子はイネゲノム中に12個存在し、それらについて分子進化解析と遺伝子発現解析を行ったところ、1つがstrerol生合成に、また他の1つがtriterpene生合成に関与している可能性が見いだされたのでこれを報告する。

DOI： 10.14841/jspp.2009.0.0206.0

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：英語  

<p>Flagellin, a component of the flagellar filament of Pseudomonas syringae pv. tabaci 6605 (Pta), induces hypersensitive reaction in its non-host Arabidopsis thaliana. We identified the WRKY41 gene, which belongs to a multigene family encoding WRKY plant-specific transcription factors, as one of the flagellin-inducible genes in A. thaliana. Expression of WRKY41 is induced by inoculation with the incompatible pathogen P. syringae pv. tomato DC3000 (Pto) possessing AvrRpt2 and the non-host pathogens Pta within 6-h after inoculation, but not by inoculation with the compatible Pto. Expression of WRKY41 was also induced by inoculation of A. thaliana with an hrp-type three secretion system (T3SS)-defective mutant of Pto, indicating that effectors produced by T3SS in the Pto wild-type suppress the activation of WRKY41. Arabidopsis overexpressing WRKY41 showed enhanced resistance to the Pto wild-type but increased susceptibility to Erwinia carotovora EC1. WRKY41-overexpressing Arabidopsis constitutively expresses the PR5 gene, but suppresses the methyl jasmonate-induced PDF1.2 gene expression. These results demonstrate that WRKY41 may be a key regulator in the cross talk of salicylic acid and jasmonic acid pathways.</p>

DOI： 10.1007/s00438-007-0315-0

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：GENETICS SOC JAPAN  

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記述言語：英語  

<p>Flagellin in Pseudomonas syringae is a potent elicitor of defense responses including hypersensitive cell death in dicot plants. The oligopeptides flg22 consisting of 22 conserved amino acids near the N-terminus of flagellins is reported to induce plant defense responses. Because glycosylation of the central domain of flagellin affects its elicitor activity, we investigated whether any peptide sequence in addition to flg22 is required for flagellin-induced hypersensitive reaction. A study of recombinant flagellin polypeptides indicated that the N-terminal domain including the conserved flg22 is required for flagellin-induced hypersensitive cell death in Arabidopsis thaliana.</p>

DOI： 10.1007/s10327-007-0017-9

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記述言語：英語   出版者・発行元：BLACKWELL PUBLISHING  

A glycosylation island is a genetic region required for glycosylation. The glycosylation island of flagellin in Pseudomonas syringae pv. tabaci 6605 consists of three orfs: orf1, orf2 and orf3. Orf1 and orf2 encode putative glycosyltransferases, and their deletion mutants, Delta orf1 and Delta orf2, exhibit deficient flagellin glycosylation or produce partially glycosylated flagellin respectively. Digestion of glycosylated flagellin from wild-type bacteria and non-glycosylated flagellin from Delta orf1 mutant using aspartic N-peptidase and subsequent HPLC analysis revealed candidate glycosylated amino acids. By generation of site-directed Ser/Ala-substituted mutants, all glycosylated amino acid residues were identified at positions 143, 164, 176, 183, 193 and 201. Matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry (MS) analysis revealed that each glycan was about 540 Da. While all glycosylation-defective mutants retained swimming ability, swarming ability was reduced in the Delta orf1, Delta orf2 and Ser/Ala-substituted mutants. All glycosylation mutants were also found to be impaired in the ability to adhere to a polystyrene surface and in the ability to cause disease in tobacco. Based on the predicted tertiary structure of flagellin, S176 and S183 are expected to be located on most external surface of the flagellum. Thus the effect of Ala-substitution of these serines is stronger than that of other serines. These results suggest that glycosylation of flagellin in P. syringae pv. tabaci 6605 is required for bacterial virulence. It is also possible that glycosylation of flagellin may mask elicitor function of flagellin molecule.

DOI： 10.1111/j.1462-5822.2005.0674.x

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：AMER PHYTOPATHOLOGICAL SOC  

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DOI： 10.1007/s10327-005-0261-9

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記述言語：英語  

DOI： 10.1007/s10327-006-0279-7

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DOI： 10.1007/s10327-006-0283-y

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記述言語：英語   出版者・発行元：American Society for Microbiology  

Pseudomonas syringae pv. tabaci 6605 possesses a genetic region involved in flagellin glycosylation. This region is composed of three open reading frames: orf1, orf2, and orf3. Our previous study revealed that orf1 and orf2 encode glycosyltransferases; on the other hand, orf3 has no role in posttranslational modification of flagellin. Although the function of Orf3 remained unclear, an orf3 deletion mutant (Delta orf3 mutant) had reduced virulence on tobacco plants. Orf3 shows significant homology to a 3-oxoacyl-(acyl carrier protein) synthase III in the fatty acid elongation cycle. The Delta orf3 mutant had a significantly reduced ability to form acyl homoserine lactones (AHLs), which are quorum-sensing molecules, suggesting that Orf3 is required for AHL synthesis. In comparison with the wild-type strain, swarming motility, biosurfactant production, and tolerance to H2O2 and antibiotics were enhanced in the Delta orf3 mutant. A scanning electron micrograph of inoculated bacteria on the tobacco leaf surface revealed that there is little extracellular polymeric substance matrix surrounding the cells in the Delta orf3 mutant. The phenotypes of the Delta orf3 mutant and an AHL synthesis (Delta psyI) mutant were similar, although the mutant-specific characteristics were more extreme in the Delta orf3 mutant. The swarming motility of the Delta orf3 mutant was greater than that of the Delta psyI mutant. This was attributed to the synergistic effects of the overproduction of biosurfactants and/or alternative fatty acid metabolism in the Delta orf3 mutant. Furthermore, the amounts of iron and biosurfactant seem to be involved in biofilm development under quorum-sensing regulation in P. syringae pv. tabaci 6605.

DOI： 10.1128/JB.00763-06

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記述言語：英語  

DOI： 10.1007/s10327-006-0278-8

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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DOI： 10.1007/s10327-005-0201-8

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DOI： 10.1007/s10327-005-0200-9

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：OXFORD UNIV PRESS  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：OXFORD UNIV PRESS  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：英語   出版者・発行元：ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD  

A polypeptide fungal suppressor from a pea pathogen Mycosphaerella pinodes plays a key role in pathogenesis by suppressing elicitor-induced defense response(s) in pea (Pisum sativum L). In this study, we show that treatment of pea tissues with the polysaccharide elicitor secreted by M. pinodes results in rapid increased activation of two myelin basic protein (MBP)-dependent kinases p44 (approximate to44 kDa) and p48 (approximate to48 kDa) within 15-30 min upon elicitation. Interestingly, the suppressor inhibited the elicitor-induced activation of only p44 kinase. While the defense-inducing signalling molecules, chitosan and salicylic acid (SA) activated the p44 and p48 kinases, methyl jasmonate (MeJA) did not. The abiotic stress signals, abscisic acid (ABA), NaCl and wounding activated the p48 kinase alone. These results demonstrate that MAPKs are differentially activated in response to pathogen invasion and abiotic stress in pea. Furthermore, specific inhibition of elicitor-induced p44 kinase activation by a MAPKK inhibitor, PD098059 and protein kinase inhibitor, K252a correlated with the suppression of elicitor-induced phenylalanine ammonia lyase (PAL) gene expression, supporting a role for p44 in the elicitor-induced defense response(s) in pea. Inhibition of p44 by the phosphoinositide (PI) turnover inhibitor, neomycin (a fungal suppressor mimic), and potentiation of p44 by the diacylglycerol (DAG) kinase inhibitor, R59022 indicated that p44 may be acting downstream of (PI) metabolism. Taken together, our results indicate that suppressor of defense elicitation from M. pinodes acts through inhibition of a MAPK (p44), possibly through a PI signaling pathway, facilitating the establishment of basic compatibility during infection of pea. (C) 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.pmpp.2004.05.003

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：OXFORD UNIV PRESS  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

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記述言語：日本語   出版者・発行元：日本植物病理学会  

エンドウ褐紋病菌Mycosphaerella pinodesのマメ科植物に対する病原性が調べられた結果,本菌は自然宿主であるエンドウの他に,赤クローバー,ナツフジ,キハギ,アルファルファに感染する.これら植物における感染は,同菌の生産するサプレッサーによるナシ黒斑病菌に対する受容性誘導の程度と一致し,サプレッサーが本菌の宿主範囲を決定する因子であることをすでに報告した(Oku et al.,1980).ここでは,植物疾病の分子機構の解明に向けた新たなモデルシステムの開発を目的として,アルファルファに近縁であるMedicago truncatulaに対する褐紋病菌の病原性について調べた.この結果,各国より集められた18種のエコタイプの全てに感染し病斑が誘導されたが,うち2種では柄子殻の形成が認められた.M.truncatulaは,ゲノムサイズが小さく,遺伝子地図・ESTの充実,形質転換の容易さなどから,近年,マメ科のモデルとして選定されている.M.truncatula-M.pinodesの相互作用のモデル化は,病原性・共生といった多様な微生物との相互作用の理解につながる格好のモデルになるものと考えられる.

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記述言語：日本語   出版者・発行元：日本植物病理学会  

植物体内には,病原菌サプレッサー様の活性を示す物質が含まれていることが,イネ,オオムギ,エンドウなどで明らかにされてきた.今回,モデル植物であるArabidopsis thaliana Col-1を用いて類似因子を探索した.約1ヶ月苗の地上部から凍結・摩砕・遠心と分配抽出により水層部を回収した.凍結乾燥後,GFC等で分画し分子量1万以下の一つの活性ピークを得た.この標品で処理されたCol-1,WSなど8種のエコタイプ上ではAscochyta rabieiを始めとする4種の非病原菌の感染が成立した.本画分は,A.thalianaの活性酸素生成やファイトアレキシン生産を阻害した.一方,本画分で処理されたキャベツ,タバコ,トマト,エンドウにはA.rabieiは感染できず,予め本画分で処理されたエンドウに褐紋病菌を接種したところ感染が阻害された.この結果は,本画分が病原菌サプレッサーのように異種植物にはエリシターとして認識されることを示唆している.このように,モデル植物中にも種特異的な内生サプレッサーが存在することが判明した.

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記述言語：日本語   出版者・発行元：日本植物病理学会  

エンドウcDNAライブラリーから細胞外で働くことが予想される5種類のペルオキシダーゼ(POX)がクローニングされた(14年度大会).今回,細胞壁から始まる防御システムを明らかにする第1段階として,細胞壁NTPaseが生成するリン酸のPOX遺伝子の発現に対する影響について解析した.褐紋病菌エリシター処理5時間後には,PAL-mRNAと同様にPOX11,13,14,21,29-mRNAの増加が認められた.しかし,1mMリン酸処理ではPOX11,14,21-mRNAの増加は誘導されたが,POX13,29の増加は認められなかった.エリシター処理エンドウ組織表層にはPOXに依存した活性酸素生成が誘導される(Kiba et al.,1996).そこで,NBTを用いて調べた結果,リン酸処理6および12時間後には顕著な活性上昇が観察された.本活性上昇はシクロヘキシミドやSHAMで阻害されたが,ネオマイシンには非感受性であった.以上の結果は,(1)リン酸による活性酸素生成の誘導とPOX遺伝子の発現には関連があること,(2)POXの発現にはファイトアレキシン生産とは異なる情報伝達系が関連することを示唆する.

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記述言語：日本語   出版者・発行元：日本植物病理学会  

Differential Display法によるスクリーニングの結果,タンパク質エリシター・エリシチン応答性遺伝子の1つとして,タバコ培養細胞BY-2より,プロテインキナーゼ様遺伝子を単離した.本遺伝子の全長cDNAを単離したところ,本遺伝子産物は膜貫通ドメインを有し,N 末側にレクチン様の受容体ドメイン,C末側にセリン/スレオニン型のプロテインキナーゼ(PK)ドメインを有した受容体様プロテインキナーゼ(NtlecRPK)であると推測された.さらに,NtlecRPKの機能を解析するために,NtlecRPKのPKドメインを組換えタンパク質として生産し,本プロテインキナーゼの基質タンパク質の同定を試みた.in vitro kinase assayの結果,BY-2タンパク質中には,組換えPKにより特異的にリン酸化される約45kDa及び40kDaのタンパク質が存在すること,約45kDaタンパク質のリソ酸化はエリシチン処理により増加することが示された.現在,これら2種のタンパク質の同定を進めている.

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記述言語：日本語   出版者・発行元：日本植物病理学会  

エンドウ褐紋病菌の生産するサプレッサーに応答性のエンドウ遺伝子S64はジャスモン酸合成系の12-oxophytodienoic acid reductase(OPR)と高い相同性を示す.S64の発現制御機構を解析する為,これまでに6つのOPR遺伝子が単離されS64とOPR2が同一であることが明らかとなった.6つのOPR遺伝子の推定アミノ酸配列は互いに80%以上の相同性を有したが,イントロンやプロモーター構造などに多様性が見られた.次に各OPR遺伝子に特異的なプライマーを作成し,RT-PCR法を用いて発現解析を行った.その結果,親和性病原菌の接種,サプレッサー処理で最も強く誘導されるOPR遺伝子はOPR2であることが明らかとなった.また,これまでに解析された各OPR組換えタンパク質の酵素活性と今回の結果から,各OPR遺伝子の相同性による分類は,遺伝子構造,発現の特性,酵素活性による分類と一致し,各々が異なる機能を有することが示唆された.

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記述言語：英語   出版者・発行元：岡山大学農学部  

Recently, we, isolated cDNA clone, PsDof1, from clicitor-treated pea cDNA library. The putative gene product, a PsDof1, encodes DNA binding protein that specifically binds the DNA fragment containing AAAG core sequence. In this paper we report that GST-PsDof1 fusion protein specifically binds to the promoter region containing AAAG core sequence(s) of PsCHS1, one of the elicitor-inducible genes encoding chalcone synthase (CHS). Furthermore the addition of DNA fragment containing AAAG motif to the 35S minimal promoter provided the elicitor-responsibility in transient transfection assay using pea protoplasts. These results suggest that PsDof1 might be involved in defense responses by acitivating the transcription by a binding to AAAG core sequence in the promoter of the defense-related genes in pea.エリシターを処理したエンドウ上胚軸由来のRNAから作成されたcDNAライブラリーからエリシター処理により発現が増高する遺伝子候補のcDNAとしてPsDof1が単離された．大腸菌で生産されたGST-PsDof１融合タンパク質はAAAG配列をコアとするDNAに結合することが明らかにされている．本論文ではGST-PsDof１がエリシター応答性遺伝子の一つ，PsCHS1のプロモーター上のAAAGまたはCTTT配列を有する断片に特異的に結合することを明らかにした．更にAAAG配列のエリシター応答性シスエレメントとしての機能を解析するため，AAAG配列を４回繰り返したユニットをCaMV35Ｓの最小プロモーターとCATレポーター遺伝子に連結したキメラ遺伝子を構築し，エンドウプロトプラストにエレクトロポレーション法により導入した．CAT活性を指にプロモーター活性を調べたところ，AAAG配列を有するプロモーターは，エリシター処理により活性化されることが明らかとなった．これらの結果はPsDof１がエリシター応答性防御遺伝子のプロモーター上のAAAG配列に結合し，転写を活性化させる可能性を示唆している．

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記述言語：英語  

DOI： 10.1007/s10327-003-0045-z

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記述言語：英語  

DOI： 10.1007/s10327-003-0061-z

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記述言語：英語   出版者・発行元：Japanese Society for Plant Cell and Molecular Biology  

The Dof protein family is a group of plant transcription factors carrying highly conserved 52 residues referred to as the Dof domain, and belongs to the C4 zinc-finger transcription factors. We isolated various PsDof genes by PCR using the Dof-domain nucleotide sequence of the PsDof1 gene from a cDNA library of elicitor-treated pea epicotyls, and these isolated PsDof genes were then classified phylogenetically. Since the obtained genes (PsDof1 to PsDof7) were scattered over various positions of the phylogenetic tree, they were expected to perform various functions as Dof-type transcription factors. From their positions in the tree, it is expected that the PsDof2 and PsDof5 genes are defense related, as is the PsDof1 gene.

DOI： 10.5511/plantbiotechnology.20.247

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その他リンク： https://jlc.jst.go.jp/DN/JALC/00231800981?from=CiNii

記述言語：日本語   出版者・発行元：日本農芸化学会  

DOI： 10.1271/kagakutoseibutsu1962.41.511

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DOI： 10.1093/pcp/pcg042

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