| Project/Area Number |
01304014
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物保護
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| Research Institution | Mie University |
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Principal Investigator |
KUNOH Hitoshi Mie University, Faculty of Bioresources, Professor, 生物資源学部, 教授 (20024573)
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| Co-Investigator(Kenkyū-buntansha) |
TANI Toshikazu Kagawa University, Faculty of Agriculture, Professor, 農学部, 教授 (50035961)
OUCHI Seiji Kinki University, Faculty of Agriculture, Professor, 農学部, 教授 (70026433)
OKU Hachiro Okayama University, Faculty of Agriculture, Professor, 農学部, 教授 (20033144)
DOKE Noriyuki Nagoya University, Faculty of Agriculture, Professor, 農学部, 教授 (80023472)
KOHMOTO Keisuke Tottori University, Faculty of Agriculture, Professor, 農学部, 教授 (80032093)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Host-specific toxin / Suppressor / Elicitor / Resistant gene / Gene manipulation / Determinant of pathogenicity / Host resistance / Cytoskeleton |
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| Research Abstract |
The present study aimed the molecular biological investigation of the plant-pathogen interactions on the basis of cytological and physiological analyses. The cytological studies using barley coleoptiles at cellular level revealed that host cells recognized the presence of a pathogen prior to its penetration and that cytoskeleton in host cells might be involved in this recognition mechanism. The toxin of the rice blast fungus was proved to cause the leakage of electrolytes from rice cells. The molecular structure of ACT toxin of tangerine brown spot fungus was similar to that of AK and AF toxins. These results suggest that host-specific toxins might play a role as a signal for triggering pathogenicity of the pathogen. A suppressor released from the pea brown spot fungus was shown to inhibit ATPase of host plasma membranes specificaly, and thus successfully delay the expression of host defense reaction. Physiological analyses of potato-Phytophthora infestans system revealed that Ca^<++>,
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O_<2^-> and protein kinase might be related to induction of host defense responses. Together with other studies concerning lignin formation and detection of peroxidated lipids, all these results promoted our understanding of some aspects of the resistance mechanism of plants. A separate gene analyses indicated that resistant genes of avena for crown rust was closely linked with susceptible genes of victorin. Several molecular biological techniques were established during the present study : the gene manipulation technique of the pear brown spot fungus and the transformation technique for barley coleoptiles using a microinjection method. In the soybean-Phytophthora megasperma system, cDNA of an elicitor gene responsible for a resistant response of bean was successfully cloned. The resistance to this fungus was evidently enhanced in tobacco plants which had been transformed by introduction of this gene. Moreover, CMV-resistant melon plants were regenerated from melon leaves infected with Agrobacterium rhizogenesis previously transformed by introduction of CMV-resistant gene. All these results greatly enhanced our knowledges on the events occurring at the parasite-host interfaces. Less
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