权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

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.

对稻瘟病菌种特异性寄生机理进行了研究。来自杂交的F1群体，狗尾草属分离物X Tritucum分离物，在小麦上的致病性表现出双因子分离。这些基因被命名为Pwt 1和Pwt 2。另一个来自杂交的F1群体，一个燕麦分离物和一个小麦分离物，在燕麦上表现出单因子分离。该基因被命名为Pat 1。在群体分离分析中发现了紧密连锁的AFLP标记。从马唐分离物中提取了一种植物毒素。在各种禾本科植物中，马唐（Digtaria分离物的宿主）对该毒素的敏感性最高。Pyrichalasin H仅在马唐分离物中大量产生，Pyrichalasin H缺陷突变体对马唐失去致病性。马唐叶处理Pyrichalasin H成为非病原体。这些结果表明，梨孢霉H是马唐种特异性寄生的决定因子，反转录转座子MAGGY是稻瘟病菌基因组中最活跃的转座因子。MAGGY基因在稻属和狗尾草属菌株中存在，而在其它菌株中不存在。我们推测该元件可能参与了这些分离物的小种-品种特异性的进化。