研究者詳細 - 且原　真木

論文 - 且原　真木

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A wheat gene encoding an aluminum-activated malate transporter

T Sasaki, Y Yamamoto, B Ezaki, M Katsuhara, SJ Ahn, PR Ryan, E Delhaize, H Matsumoto

PLANT JOURNAL 37 ( 5 ) 645 - 653 2004年3月

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 LTD

The major constraint to plant growth in acid soils is the presence of toxic aluminum (Al) cations, which inhibit root elongation. The enhanced Al tolerance exhibited by some cultivars of wheat is associated with the Al-dependent efflux of malate from root apices. Malate forms a stable complex with Al that is harmless to plants and, therefore, this efflux of malate forms the basis of a hypothesis to explain Al tolerance in wheat. Here, we report on the cloning of a wheat gene, ALMT1 (aluminum-activated malate transporter), that co-segregates with Al tolerance in F-2 and F-3 populations derived from crosses between near-isogenic wheat lines that differ in Al tolerance. The ALMT1 gene encodes a membrane protein, which is constitutively expressed in the root apices of the Al-tolerant line at greater levels than in the near-isogenic but Al-sensitive line. Heterologous expression of ALMT1 in Xenopus oocytes, rice and cultured tobacco cells conferred an Al-activated malate efflux. Additionally, ALMT1 increased the tolerance of tobacco cells to Al treatment. These findings demonstrate that ALMT1 encodes an Al-activated malate transporter that is capable of conferring Al tolerance to plant cells.

DOI： 10.1111/j.1365-313X.2003.01991.x

Overexpression of the barley aquaporin HvPIP2;1 increases internal CO2 conductance and CO2 assimillation in the leaves of transgenic rice plants

YT Hanba, M Shibasaka, Y Hayashi, T Hayakawa, K Kasamo, Terashima, I, M Katsuhara

PLANT AND CELL PHYSIOLOGY 45 ( 5 ) 521 - 529 2004年

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 internal conductance for CO2 diffusion (g(i)) and CO2 assimilation rate were measured and the related anatomical characteristics were investigated in transgenic rice leaves that overexpressed barley aquaporin HvPIP2;1. This study was performed to test the hypothesis that aquaporin facilitates CO2 diffusion within leaves. The g(i) value was estimated for intact leaves by concurrent measurements of gas exchange and carbon isotope ratio. The leaves of the transgenic rice plants that expressed the highest levels of Aq-anti-HvPIP2;1 showed a 40% increase in g(i) as compared to g(i) in the leaves of wild-type rice plants. The increase in g(i) was accompanied by a 14% increase in CO2 assimilation rate and a 27% increase in stomatal conductance (g(s)). The transgenic plants that had low levels of Aq-anti-HvPIP2;1 showed decreases in g(i) and CO2 assimilation rate. In the plants with high levels of Aq-anti-HvPIP2;1, mesophyll cell size decreased and the cell walls of the epidermis and mesophyll cells thickened, indicating that the leaves had become xeromorphic. Although such anatomical changes could partially offset the increase in g(i) by the aquaporin, the increase in aquaporin content overcame such adverse effects.

DOI： 10.1093/pcp/pch070

Changes in roots and salt sensitivity of rice plants over-expressing aquaporin

M Katsuhara, K Koshio, M Shibasaka, Y Hayashi, T Hayakawa, K Kasamo

PLANT AND CELL PHYSIOLOGY 45 S174 - S174 2004年

Expression of an aquaporin at night in relation to the growth and root water permeability in barley seedlings

M Katsuhara, K Koshio, M Shibasaka, K Kasamo

SOIL SCIENCE AND PLANT NUTRITION 49 ( 6 ) 883 - 888 2003年12月

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 SOIL SCIENCE PLANT NUTRITION

Both root and shoot of barley seedlings showed continuous growth at night as well as in the daytime. Root hydraulic conductivity (Lp(r)) was monitored, and high Lp(r) values were recorded at night. For revealing the molecular mechanism, the presence of an aquaporin HvPIP2;1 in barley roots was investigated. The accumulation of the HvPIP2;1 transcript was mostly observed from the evening to the middle of the night. HvPIP2;1 protein was most abundant around midnight. As for tissue localization, HvPIP2;1 protein was abundant in cells involved in water transport. These results suggested the possible involvement of HvPIP2;1 in the mechanism of water transport in roots.

Over-expression of a barley aquaporin increased the shoot/root ratio and raised salt sensitivity in transgenic rice plants

M Katsuhara, K Koshio, M Shibasaka, Y Hayashi, T Hayakawa, K Kasamo

PLANT AND CELL PHYSIOLOGY 44 ( 12 ) 1378 - 1383 2003年12月

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

Barley HvPIP2;1 is a plasma membrane aquaporin and its expression was down-regulated after salt stress in barley [Katsuhara et al. (2002) Plant Cell Physiol. 43: 885]. We produced and analyzed transgenic rice plants over-expressing barley HvPIP2;1 in the present study. Overexpression of HvPIP2;1 increased (1) radial hydraulic conductivity of roots (Lp(r)) to 140%, and (2) the mass ratio of shoot to root up to 150%. In these transgenic rice plants under salt stress of 100 mM NaCl, growth reduction was greater than in non-transgenic plants. A decrease in shoot water content (from 79% to 61%) and reduction of root mass or shoot mass (both less than 40% of non-stressed plants) were observed in transgenic plants under salt stress for 2 weeks. These results indicated that over-expression of HvPIP2;1 makes rice plants sensitive to 100 mM NaCl. The possible involvement of aquaporins in salt tolerance is discussed.

DOI： 10.1093/pcp/pcg167

A metallothionein and CPx-ATPase handle heavy-metal tolerance in the filamentous cyanobacterium Oscillatoria brevis

T Liu, S Nakashima, K Hirose, Y Uemura, M Shibasaka, M Katsuhara, K Kasamo

FEBS LETTERS 542 ( 1-3 ) 159 - 163 2003年5月

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

A metallothionein (BmtA) and a CPx-ATPase (Bxa1) have been identified and characterized from the cyanobacterium Oscillatoria brevis. Both bmtA and bxa1 expression can be markedly induced in vivo by Zn2+ or Cd2+. Over-expression of bmaA or bxa1 in Escherichia coli enhances Zn2+ and Cd2+ tolerance in the transformant. Dynamic studies on the expression of two genes showed that the maximum expression of bxa1 induced by Zn2+ and Cd2+ was much quicker than that of bmtA, suggesting distinct physiological roles of metallothionein and CPx-ATPase in the handling of surplus metal. (C) 2003 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.

DOI： 10.1016/S0014-5793(03)00370-3

Increase in CO2 permeability (diffusion conductance) in leaves of transgenic rice plant over-expressing barley aquaporin

M Katsuhara, Y Hanba, M Shibasaka, Y Hayashi, T Hayakawa, K Kasamo

PLANT AND CELL PHYSIOLOGY 44 S86 - S86 2003年

A novel histidine-rich CPx-ATPase from the filamentous cyanobacterium Oscillatoria brevis related to multiple-heavy-metal cotolerance

L Tong, S Nakashima, M Shibasaka, M Katsuhara, K Kasamo

JOURNAL OF BACTERIOLOGY 184 ( 18 ) 5027 - 5035 2002年9月

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

A novel gene related to heavy-metal transport was cloned and identified from the filamentous cyanobacterium Oscillatoria brevis. Sequence analysis of the gene (the Bxa1 gene) showed that its product possessed high homology with heavy-metal transport CPx-ATPases. The CPC motif, which is proposed to form putative cation transduction channel, was found in the sixth transmembrane helix. However, instead of the CXXC motif that is present in the N termini of most metal transport CPx-ATPases, Bxa1 contains a unique Cys-Cys (CC) sequence element and histidine-rich motifs as a putative metal binding site. Northern blotting and real-time quantitative reverse transcription-PCR showed that expression of Bxa1 mRNA was induced in vivo by both monovalent (Cu+ and Ag+) and divalent (Zn2+ and Cd2+) heavy-metal ions at similar levels. Experiments on heavy-metal tolerance in Escherichia coli with recombinant Bxa1 demonstrated that Bxa1 conferred resistance to both monovalent and divalent heavy metals. This is the first report of a CPx-ATPase responsive to both monovalent and divalent heavy metals.

DOI： 10.1128/JB.184.18.5027-5035.2002

Functional analysis of water channels in barley roots

M Katsuhara, Y Akiyama, K Koshio, M Shibasaka, K Kasamo

PLANT AND CELL PHYSIOLOGY 43 ( 8 ) 885 - 893 2002年8月

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

We identified three genes homologous to water channels in the plasma membrane type subfamily from roots of barley seedlings. These genes were designated HvPIP2;1, HvPIP1;3, and HvPIP1;5 after comparison to Arabidopsis aquaporins. Competitive reverse transcription (RT)-PCR was applied in order to distinguish and to quantify their transcripts. The HvPIP2;1 transcript was the most abundant among the three in roots. Salt stress (200 mM NaCl) down-regulated HvPIP2;1 (transcript and protein), but had almost no effect on the expressions of HvPIP1;3, or HvPIP1;5. Approximately equal amounts of the transcripts of the three were detected in shoots, and salt stress enhanced the expression of HvPIP2;1 but not of HvPIP1;3, or HvPIP1;5. HvPIP2;1 protein was confirmed to be localized in the plasma membrane. Functional expression of HvPIP2;1 in Xenopus oocytes confirmed that HvPIP2;1 encoded an aquaporin that transports water. This water permeability was reduced by HgCl2, which is a typical water channel inhibitor. This activity was not modified by some inhibitors against protein kinase and protein phosphatase.

DOI： 10.1093/pcp/pcf102

Different mechanisms of four aluminum (Al)-resistant transgenes for Al toxicity in Arabidopsis

B Ezaki, M Katsuhara, M Kawamura, H Matsumoto

PLANT PHYSIOLOGY 127 ( 3 ) 918 - 927 2001年11月

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 PLANT BIOLOGISTS

We have characterized the mechanism of action of four transgenes (AtBCB [Arabidopsis blue copper-binding protein], parB [tobacco {Nicotiana tabacum} glutathione S-transferase], NtPox [tobacco peroxidase], and NtGDI1 [tobacco GDP dissociation inhibitor]) that independently Al resistance on transgenic Arabidopsis. All four transgenic lines showed lower deposition of callose after Al treatment than the Landsberg erecta ecotype of Arabidopsis, confirming that the four genes function to ameliorate Al toxicity. Influx and efflux experiments of Al ions suggested that the AtBCB gene may suppress Al absorption, whereas expression of the NtGDI1 gene promotes a release of Al in the root tip region of Arabidopsis. The total enzyme activities of glutathione S-transferases or peroxidases in transoenic lines carrying either the parB or NtPox genes were significantly higher than in the Landsberg erecta ecotype of Arabidopsis, and these enzyme activities were maintained at higher levels during Al stress. Furthermore, lipid peroxidation caused by Al stress was repressed in these two transgenic lines, suggesting that overexpression of these two genes diminishes oxidative damage caused by Al stress. Al-treated roots of trans-enic plants were also stained by 4',6-diamino-2-phenylindole to monitor cell death caused by Al toxicity. The result suggested that cell death is repressed in the NtPox line. Analysis of F-1 hybrids between the four transgenic lines suggests that more resistant transgenic plants can be constructed by combinations of these four genes.

DOI： 10.1104/pp.127.3.918

Isolation of barley saLT gene: Its relation to salt tolerance and to hormonal regulation by abscisic acid and jasmonic acid

M Katsuhara, M Yamada, K Kasamo

SOIL SCIENCE AND PLANT NUTRITION 47 ( 1 ) 187 - 193 2001年3月

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 SOIL SCIENCE PLANT NUTRITION

A homologous gene to rice salT was isolated from barley and designated as Hv-salT, Since the expression of rice salT was regulated by plant hormones (abscisic acid and jasmonic acid) and salt stress, the effects of these plant hormones and salt stress on the growth of barley seedlings and the expression of Hv-salT were investigated. In contrast to rice salT, almost no changes in the expression of Hv-salT by hormones and salt stress were detected.

Expression and stress-dependent induction of potassium channel transcripts in the common ice plant

H Su, D Golldack, M Katsuhara, CS Zhao, HJ Bohnert

PLANT PHYSIOLOGY 125 ( 2 ) 604 - 614 2001年2月

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 PLANT PHYSIOLOGISTS

We have characterized transcripts for three potassium channel homologs in the AKT/KAT subfamily (Shaker type) from the common ice plant (Mesembryanthemum crystallinum), with a focus on their expression during salt stress (up to 500 mM NaCl). Mkt1 and 2, Arabidopsis AKT homologs, and Kmt1, a KAT homolog, are members of small gene families with two to three isoforms each. Mkt1 is root specific; Mkt2 is found in leaves, flowers, and seed capsules; and Kmt1 is expressed in leaves and seed capsules. Mkt1 is present in all cells of the root, and in leaves a highly conserved isoform is detected present in all cells with highest abundance in the vasculature. MKT1 for which antibodies were made is localized to the plasma membrane. Following salt stress, MKT1 (transcripts and protein) is drastically down-regulated, Mkt2 transcripts do not change significantly, and Kmt1 is strongly and transiently (maximum at 6 h) up-regulated in leaves and stems. The detection and stress-dependent behavior of abundant transcripts representing subfamilies of potassium channels provides information about tissue specificity and the complex regulation of genes encoding potassium uptake systems in a halophytic plant.

DOI： 10.1104/pp.125.2.604

Identification and characterization of a putative heavy metal transport gene from a cyanobacterium Oscillatoria Brevis :

Liu Tong, NAKASHIMA Susumu, SHIBASAKA Mineo, KATSUHARA Maki, KASAMO Kunihiro

Plant and cell physiology 42 s208 2001年

In situ RNA hybridization using Technovit resin in Arabidopsis thaliana

K Takechi, W Sakamoto, M Katsuhara, M Murata, F Motoyoshi

PLANT MOLECULAR BIOLOGY REPORTER 17 ( 1 ) 43 - 51 1999年

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

A protocol is described for RNA in situ hybridization using thin sections prepared by Technovit resin. Technovit is a widely used resin for histological examinations. Since it does not require time-consuming processes such as removal of the resin and can be performed without high temperature treatment, a high resolution of sections could be possible compared to other resins and paraffin. Thin sections (approximately 4 mu m) were made from inflorescences of Arabidopsis thaliana embedded in Technovit 8100 resin, and in situ hybridization was performed using the protocol described in this article. Hybridization signals were observed using LEAFY and other genes as probes, showing that this resin can be used for in situ analysis. In our experiments, the most important factor for a successful in situ, hybridization pattern was to optimize the RNase A concentration after hybridization. We routinely used RNase A at a concentration of 2-5 ng/ml, a concentration much lower than that used for paraffin embedding method. Thus, the use of the Technovit resin for plant tissue embedding results in a faster protocol and greater quality than allowed by paraffin sections.

Intracellular pH and proton-transport in barley root cells under salt stress: In vivo 31P-NMR study

Maki Katsuhara, Yoshiaki Yazaki, Katsuhiro Sakano, Toshio Kawasaki

Plant and Cell Physiology 38 ( 2 ) 155 - 160 1997年

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

Salt stress-induced changes of intracellular pH and in levels of phosphorous compounds were monitored in intact root tips of barley seedlings (Hordeum vulgare cv. Akashinriki) by in vivo 31P-nuclear magnetic resonance (NMR) spectroscopy. Vacuolar alkalization was observed after treatment with both 300 and 500 mM NaCl. Much of the observed apparent alkalization of the cytoplasm was eliminated when the effect of Na+ ions on the titration curve was considered. Within 1 h after the initiation of salt stress, levels of glucose-6-phosphate and UDP-glucose decreased markedly, and such decreases might lead directly or indirectly to cell death. Simultaneous measurements of the external and intracellular pH revealed the promotion of external acidification and internal alkalization during salt stress. Possible mechanisms of Na+/H+ antiport at the tonoplast and the role of proton-pump in the plasma membrane are discussed.

DOI： 10.1093/oxfordjournals.pcp.a029146

Salt stress induced nuclear and DNA degradation in meristematic cells of barley roots

Maki Katsuhara, Toshio Kawasaki

Plant and Cell Physiology 37 ( 2 ) 169 - 173 1996年

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 Society of Plant Physiologists

Root growth of barley (Hordeum vulgare L., ev. Akashinriki) was inhibited by 200 mM NaCl, when 1 mM CaCl2 was present in the hydroponic culture solution. Increasing the CaCl2 up to 10 mM partially prevented this inhibition. However, inhibition also occurred with 100 mM NaCl in the presence of 0.1 mM CaCl2. The nuclei of meristematic cells in roots in which growth had been inhibited by salt stress were studied after staining with DAPI (4',6-diamino-2-phenylindol). Nuclear deformation of the cells occurred with 12 h of salt stress with 500 mM NaCl, and was followed by degradation. The nuclear degradation was also observed when the roots were exposed to more than 300 mM NaCl for 24 h. Biochemical analysis revealed that nuclear degradation was accompanied by apoptosislike DNA fragmentation. The intracellular mechanisms of nuclear degradation in cells after salt stress are discussed.

DOI： 10.1093/oxfordjournals.pcp.a028928

Distribution and Production of trans-Aconitic Acid in Barnyard Grass (Echinochloa crus-galli var. oryzicola) as Putative Antifeedant against Brown Planthoppers :

KATSUHARA Maki, SAKANO Katsuhiro, SATO Mamoru, KAWAKITA Hiromu, KAWABE Susumu

Plant and cell physiology 34 ( 2 ) 251 - 254 1993年

記述言語：英語出版者・発行元：Japanese Society of Plant Physiologists

A quantitative analysis of organic acid in leaves of barnyard grass revealed that the contents of trans-aconitic acid were high, suggesting that this compound may act as an antifeedant against brown planthoppers. However, trans-aconitic acid could not be detected in the phloem sap which was considered to be the main nutrient source for brown planthoppers. trans-Aconitic acid was formed in vitro from cis-aconitic acid through the aconitate isomerase activity which was detected only in the leaf sheath, but not in the leaf blade.

その他リンク： https://projects.repo.nii.ac.jp/?action=repository_uri&item_id=181825

萎縮病クワから師管液の採取並びにＭＬＯの検出

川北弘, 且原真木

日本蚕糸学雑誌 62 ( 2 ) 125 - 131 1993年

記述言語：日本語出版者・発行元：日本蠶絲學會

クワ萎縮病の病原であるマイコプラズマ様微生物 (MLO) が, ベッコウハゴロモ (Ricania japonica Melichar) を用いたスタイレクトミー法 (YAGレーザー光線により昆虫の口針を切断) により採取された。すなわち, この方法で採取した萎縮病クワの師管液をDAPI (4′,6-ジアミジノ-2-フェニールインドール) で染色すると, 健全師管液では観察されない蛍光粒子としてMLOが観察された。さらに師管液を透過型電子顕微鏡で観察すると, 罹病クワ組織内と同形態のMLOが検出された。<br>一方, 萎縮病の媒介昆虫であるヨコバイ類および他の供試した数種の半翅目昆虫は, このレーザー・スタイレクトミー法には利用出来なかった。これら利用不能なヨコバイ類のレーザー切断口針は, 一部が脱落するなど著しく変形していたのに対し, 師管液が採取されたベッコウハゴロモの口針は, 組織内によく挿入されたままの状態で残ることが走査型電子顕微鏡により観察された。

DOI： 10.11416/kontyushigen1930.62.125

その他リンク： http://agriknowledge.affrc.go.jp/RN/2010510238

Cytoplasmic Alkalization and Cytoplasmic Streaming Induced by Light and Histidine in Leaf Cells of Egeria densa: in vivo 31P-NMR study

Yoshito Tominaga, Kazuyuki Kuchitsu, Maki Katsuhara, Masashi Tazawa, Shigetoh Miyachi

Plant and Cell Physiology 32 ( 2 ) 261 - 268 1991年3月

Patch-clamp study on ion channels in the tonoplast of nitellopsis obtusa

Maki Katsuhara, Tetsuro Mimura, Masashi Tazawa

Plant and Cell Physiology 32 ( 2 ) 179 - 184 1991年

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

Cytoplasmic drops covered with the tonoplast were prepared from internodal cells of Nitellopsis grown in fresh water. Applying the patch-clamp technique and the microinjection technique to such drops, we characterized the ion channels in the tonoplast. Both in cell-free patches and in the cytoplasmic-drop-attached patches, the tonoplast K+ channel was identified. The permeability ratio between Na+ and K+ was calculated to be 0.2. This channel would provide a molecular basis for the Na+/K+ exchange at the tonoplast. In cell-free patches, the K+channel was not activated by Ca2+. However, in the case of attached patches, microinjection of Ca2+ into a drop activated the K+ channel with a lag of a few seconds, suggesting that some cytoplasmic factor(s) may mediate the activation of the K+ channel by Ca2+. The conductance of this channel was not changed by cytoplasmic Ca2+, but the probability of opening increased markedly. In addition to the K+ channel, a second type of channel was also identified in cell-free patches. This channel may be the Cl- channel. © 1991 The Japanese Society of Plant Physiologists(JSSP).

DOI： 10.1093/oxfordjournals.pcp.a078062

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