| Project/Area Number |
13660052
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
植物保護
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| Research Institution | Tottori University |
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Principal Investigator |
KODAMA Motoichiro Tottori University, Faculty of Agriculture, Assistant Professor, 農学部, 講師 (00183343)
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| Co-Investigator(Kenkyū-buntansha) |
OTANI Hiroshi Tottori University, Faculty of Agriculture, Assistant Professor, 農学部, 教授 (50032305)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2002: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2001: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | plant pathogen / host-specific toxin / AAL-toxin / AM-toxin / pathogenicity gene / horizontal gene transfer / ポリケチド / CD染色体 |
|---|
| Research Abstract |
Fungal pathogenicity are predicted to release signaling molecules essential for path ogenicity during the process of infection. Although essential components for fungal pathogenesis are still unknown in many plant pathogenic fungi, certain fungal pathogens, especially the genera Alternaria and Cochliobolus, are known to produce host-specific toxins (HSTs) as compatibility agents. There are now ten or more Alternaria pathogena, mainly A. alternata pathotypes, known to produce HSTs, and the structures of most of the toxins have been elucidated. HSTs from A.alternata pathotypes have been classified into three groups based on their chemical structures, I.e.polyketides, cyclic peptides and decatrienoic acid esters. Recently a polyketied synthetase gene and a cyclic-peptide synthetase gene, involved in AAL-toxin and AM-toxin biosynthesis, respectively, have been cloned and characterized. In both cases, targeted gene disruption lead to elimination of toxin production and loss of pathogenisity indicating that HST biosynthetic genes are fungal pathogenicity determinants. These HST biosynthetic genes also reside on conditionally dispensable chromosomes found only in the pathogenic and HST-producing strains of A.alrernata and homologues of the genes were not detected in nonpathogenic strains of A.alrernata. This suggests that these genes may have been acquired by horizontal gene transfer and provides a possible mechanism whereby new pathotypes could arise in nature.
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