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Molecular analysis of species-specific parasitism in Magnaporthe grisea

稻瘟病菌物种特异性寄生的分子分析

基本信息

批准号：
10460022
负责人：
TOSA Yukio
金额：
$ 5.7万
依托单位：
KOBE UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

Mechanisms of the species-specific parasitism in Magnaporthe grisea were investigated. An F1 population derived from a cross, a Setaria isolate x a Tritucum isolates, showed bifactorial segregation in the pathogenicity on wheat. These genes were designated as Pwt1 and Pwt2. Another F1 population derived from a cross, an Avena isolate and a Triticum isolate, showed monofactorial segregation on oat. This gene was designated as Pat1. Closely linked AFLP markers were found in bulked segregant analyses. Chromosome walking is under way toward cloning of those genes.A phytotoxin was extracted from a Digitaria isolate. The toxin was revealed to be Pyrichalasin H.Among various gramineous plants, crabgrass (the host of Digtaria isolates) showed the highest susceptibility to this toxin. Pyrichalasin H was produced in a large quantity only by Digitaria isolates, and Pyrichalasin H-defidient mutants lost their pathogenicity on crabgrass. Crabgrass leaves treated with Pyrichalasin H became accessible to nonpathogens. These results suggested that Pyrichalasis H is a determinant of the species-specific parasitism of Digitaria isolates.Retrotransposon MAGGY was the most active element among transposable elements that have been found in the genome of Magnaporthe grisea. MAGGY was present in Oryza isolates and Setaria isolates, but absent in other isolates. We assuned that this element may have been involved in the evolution of the race- cultivar specificity in those isolates.

研究了稻瘟病病菌的种特异性寄生机理。一个杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种杂种。这些基因被命名为Pwt1和Pwt2。另一个由Avena分离物和Triticum分离物杂交而来的F1群体在燕麦上表现出单因子分离。该基因被命名为Pat1。在大量分离分析中发现紧密相连的AFLP标记。染色体行走正在朝着克隆这些基因的方向发展。从地黄分离物中提取了一种植物毒素。结果表明，该毒素为Pyrichalasin h .。在禾本科植物中，蟹草（Digtaria菌株的寄主）对该毒素的敏感性最高。Pyrichalasin H仅在Digitaria分离株中大量产生，缺乏Pyrichalasin H的突变体对杂草失去了致病性。用Pyrichalasin H处理过的蟹草叶片变得容易被非病原体接触。这些结果表明，Pyrichalasis H是Digitaria分离物种特异性寄生的决定因素。反转录转座子MAGGY是稻瘟病菌基因组中发现的最活跃的转座子。MAGGY在Oryza和Setaria分离株中存在，但在其他分离株中不存在。我们假设这一因素可能参与了这些分离株的种-品种特异性的进化。