我国稻瘟病菌的遗传多样性及其地理分布(英文)

用重复序列探针ＭＧＲ５８６与限制性内切酶ＥｃｏＲ１组合，分析了在我国１９８０～１９９６年期间的１７省（市）１４６个不同稻区４７５个稻瘟病菌株（下简称菌株）的限制性片段长度多态性（ＲＦＬＰｓ），依其ＭＧＲ－ＤＮＡ指纹（下简称指纹）的相似率，结合病菌的致病性测定，将表现为４８个不同致病型的４７５个菌株区分为５６个谱系，每个谱系的寄主范围有限，且与不同稻区稻瘟病的群体结构差异明显．菌株的指纹分析和致病性测定结果表明，稻瘟菌有远距离传播的可能性，并在适宜的气候和人工接种条件下，草瘟菌和稻瘟菌可彼此互交．文中，作者还分析了不同稻区稻瘟菌谱系和毒性之间的关系，以期明确该菌的致病性变异及其演化过程，为改进种质资源的筛选方法和持抗育种的程序提供科学依据．

Genetic Diversity and Geographic Distribution of Magnaporthe grisea in China

The MGR DNA fingerprintings of 475 isolates collected from 146 different rice areas in 17 provinces (city) during 1980-1996 have been studied with a dispersed repeated sequence probe of MGR586 / EcoR1 digest combination. The fingerprint data documented a generalized genetic organization. Forty eight pathotypes of Magnaporthe grisea can be distinguished into 56 separate lineages based on MGR DNA fingerprint similarity. Each lineage had a limited host cultivar range and was associated with one to several closely related pathotypes, and the relationships between and among pathotypes were maintained over several years across broad geographic distribution. The cultivar and pathotype associations indicated that the lineages expressed historically divergent virulence spectra. The MGR DNA fingerprinting and pathotyping indicated that grass pathogens and rice pathogens could infect each other occasionally under suitable climatic and artificial inoculation conditions; and the fungi had the capability of long distance transmission. The relationships between lineage and virulence in M.grisea of China could be analyzed further in different rice growing areas according to the present study. MGR DNA fingerprint analysis provides the genealogical framework for evaluating pathogen variation that is essential for understanding epidemiology and pathotype evolution, as well as for improving the screening of resistance germplasm and for designing more durable resistance breeding to blast.