掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/S11103-021-01217-W

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/TPJ.15760

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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.17751

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/PCE.14126

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掲載種別：研究論文（学術雑誌）  

DOI： 10.3389/FPLS.2021.688565

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/JXB/ERAA341

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掲載種別：研究論文（学術雑誌）  

DOI： 10.5511/PLANTBIOTECHNOLOGY.20.0511B

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/PCE.13775

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/JXB/ERAA206

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/J.POSTHARVBIO.2019.110949

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1080/15592324.2019.1655335

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1104/PP.18.01426

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/JXB/ERZ041

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/TPJ.13883

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/JXB/ERX274

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/S41598-017-03907-2

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/TREEPHYS/TPW134

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記述言語：中国語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Crop Science Society of Japan  

DOI： 10.1626/jcs.86.367

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Two phenolamides (PAs), p-coumaroylputrescine and feruloylputrescine strongly accumulate in rice (Oryza sativa cv. Nipponbare) leaves subjected to attack of chewing and sucking herbivores. Here we identified and characterized in vitro three novel rice genes that mediated coumaroyl-CoA/feruloyl-CoA conjugation to polyamines, putrescine and agmatine. Interestingly, two genes were highly specific for their polyamine substrates, encoding putrescine N-hydroxycinnamoyltransferase and agmatine N-hydroxycinnamoyltransferase, while the third enzyme could use both polyamines and it was therefore annotated as putrescine/agmatine N-hydroxycinnamoyltransferase. All genes were preferentially expressed in rice roots and developing flowers, and in addition, the putrescine/agmatine N-hydroxycinnamoyltransferase transcripts were strongly induced by wounding in the young rice leaves. Because the wound response of this gene was only partially suppressed in the jasmonoyl-L-isoleucine deficient plants (Osjar1), it suggests that its upregulation (as well as inducible PAs in rice) may be largely independent of jasmonoyl-L-isoleucine signaling pathway. The finding of three closely related genes with a similar and/or overlapping activity in PA biosynthesis provides another striking example of rapid diversification of plant metabolism in response to environmental stresses in nature.

DOI： 10.1111/jipb.12480

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Induced plant defense responses against insect herbivores are triggered by wounding and/or perception of herbivore elicitors from their oral secretions (OS) and/or saliva. In this study, we analyzed OS isolated from two rice chewing herbivores, Mythimna loreyi and Parnara guttata. Both types of crude OS had substantial elicitor activity in rice cell system that allowed rapid detection of early and late defense responses, i.e. accumulation of reactive oxygen species (ROS) and defense secondary metabolites, respectively. While the OS from M. loreyi contained large amounts of previously reported insect elicitors, fatty acid-amino acid conjugates (FACs), the elicitor-active P. guttata's OS contained no detectable FACs. Subsequently, elicitor activity associated with the high molecular mass fraction in OS of both herbivores was identified, and shown to promote ROS and metabolite accumulations in rice cells. Notably, the application of N-linolenoyl-Gln (FAC) alone had only negligible elicitor activity in rice cells; however, the activity of isolated elicitor fraction was substantially promoted by this FAC. Our results reveal that plants integrate various independent signals associated with their insect attackers to modulate their defense responses and reach maximal fitness in nature.

DOI： 10.1038/srep32537

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Plants defend against attack from herbivores by direct and indirect defence mechanisms mediated by the accumulation of phytoalexins and release of volatile signals, respectively. While the defensive arsenals of some plants, such as tobacco and Arabidopsis are well known, most of rice's (Oryza sativa) defence metabolites and their effectiveness against herbivores remain uncharacterized. Here, we used a non-biassed metabolomics approach to identify many novel herbivory-regulated metabolic signatures in rice. Most were up-regulated by herbivore attack while only a few were suppressed. Two of the most prominent up-regulated signatures were characterized as phenolamides (PAs), p-coumaroylputrescine and feruloylputrescine. PAs accumulated in response to attack by both chewing insects, i.e. feeding of the lawn armyworm (Spodoptera mauritia) and the rice skipper (Parnara guttata) larvae, and the attack of the sucking insect, the brown planthopper (Nilaparvata lugens, BPH). In bioassays, BPH insects feeding on 15% sugar solution containing p-coumaroylputrescine or feruloylputrescine, at concentrations similar to those elicited by heavy BPH attack in rice, had a higher mortality compared to those feeding on sugar diet alone. Our results highlight PAs as a rapidly expanding new group of plant defence metabolites that are elicited by herbivore attack, and deter herbivores in rice and other plants.

DOI： 10.1111/pce.12640

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掲載種別：研究論文（学術雑誌）  

DOI： 10.5511/PLANTBIOTECHNOLOGY.16.0503A

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Anthocyanin pigments and associated flavonoids have demonstrated antioxidant properties and benefits for human health. Consequently, current plant bioengineers have focused on how to modify flavonoid metabolism in plants. Most of that research, however, does not consider the role of natural biotic stresses (e.g., herbivore attack). To understand the influence of herbivore attack on the metabolic engineering of flavonoids, we examined tobacco plants overexpressing the Arabidopsis PAP1 gene (encoding an MYB transcription factor), which accumulated anthocyanin pigments and other flavonoids/phenylpropanoids. In comparison to wild-type and control plants, transgenic plants exhibited greater resistance to Spodoptera litura. Moreover, herbivory suppressed the PAP1-induced increase of transcripts of flavonoid/phenylpropanoid biosynthetic genes (e.g., F3H) and the subsequent accumulation of these genes' metabolites, despite the unaltered PAP1 mRNA levels after herbivory. The instances of down-regulation were independent of the signaling pathways mediated by defense-related jasmonates but were relevant to the levels of PAP1-induced and herbivory-suppressed transcription factors, An1a and An1b. Although initially F3H transcripts were suppressed by herbivory, after the S. litura feeding was interrupted, F3H transcripts increased. We hypothesize that in transgenic plants responding to herbivory, there is a complex mechanism regulating enriched flavonoid/phenylpropanoid compounds, via biotic stress signals.

DOI： 10.1371/journal.pone.0108849

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

We previously identified a gene related to the SEC14-gene phospholipid transfer protein superfamily that is induced in Nicotiana benthamiana (NbSEC14) in response to infection with Ralstonia solanacearum. We here report that NbSEC14 plays a role in plant immune responses via phospholipid-turnover. NbSEC14-silencing compromised expression of defense-related PR-4 and accumulation of jasmonic acid (JA) and its derivative JA-Ile. Transient expression of NbSEC14 induced PR-4 gene expression. Activities of diacylglycerol kinase, phospholipase C and D, and the synthesis of diacylglycerol and phosphatidic acid elicited by avirulent R. solanacearum were reduced in NbSEC14-silenced plants. Accumulation of signaling lipids and activation of diacylglycerol kinase and phospholipases were enhanced by transient expression of NbSEC14. These results suggest that the NbSEC14 protein plays a role at the interface between lipid signaling-metabolism and plant innate immune responses.

DOI： 10.1371/journal.pone.0098150

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Plants produce jasmonic acid (JA) and its amino acid conjugate, jasmonoyl-L-isoleucine (JA-Ile) as major defense signals in response to wounding and herbivory. In rice (Oryza sativa), JA and JA-Ile rapidly increased after mechanical damage, and this increase was further amplified when the wounds were treated with oral secretions from generalist herbivore larvae, lawn armyworms (Spodoptera mauritia), revealing for the first time active perception mechanisms of herbivore-associated elicitor(s) in rice. In the rice genome, two OsJAR genes can conjugate JA and Ile and form JA-Ile in vitro; however, their function in herbivory-induced accumulation of JA-Ile has not been investigated. By functional characterization of TOS17 retrotransposon-tagged Osjar1 plants and their response to simulated herbivory, we show that OsJAR1 is essential for JA-Ile production in herbivore-attacked, field-grown plants. In addition, OsJAR1 was required for normal seed development in rice under field conditions. Our results suggest that OsJAR1 possesses at least two major functions in rice defense and development that cannot be complemented by the additional OsJAR2 gene function, although this gene previously showed overlapping enzyme activity in vitro.

DOI： 10.1111/jipb.12057

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The awn, an apical extension from the lemma of the spikelet, plays important roles in seed dispersal, burial, and photosynthesis. Barley typically has long awns, but short-awn variants exist. The short awn 2 (lks2) gene, which produces awns about 50% shorter than normal, is a natural variant that is restricted to Eastern Asia. Positional cloning revealed that Lks2 encodes a SHI-family transcription factor. Allelism tests showed that lks2 is allelic to unbranched style 4 (ubs4) and breviaristatum-d (ari-d), for which the phenotypes are very short awn and sparse stigma hairs. The gene identity was validated by 25 mutant alleles with lesions in the Lks2 gene. Of these, 17 affected either or both conserved regions: the zinc-binding RING-finger motif and the IGGH domain. Lks2 is highly expressed in awns and pistils. Histological observations of longitudinal awn sections showed that the lks2 short-awn phenotype resulted from reduced cell number. Natural variants of lks2 were classified into three types, but all shared a single-nucleotide polymorphism (SNP) that causes a proline-to-leucine change at position 245 in the IGGH domain. All three lks2 natural variants were regarded as weak alleles because their awn and pistil phenotypes are mild compared with those of the 25 mutant alleles. Natural variants of lks2 found in the east of China and the Himalayas had considerably different sequences in the regions flanking the critical SNP, suggesting independent origins. The available results suggest that the lks2 allele might have a selective advantage in the adaptation of barley to high-precipitation areas of Eastern Asia.

DOI： 10.1093/jxb/ers182

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