四川籼稻区稻瘟病菌群体遗传结构

应用rep-PCR分子指纹技术对2000～2002年采自四川6个籼稻自然生态区的137个稻瘟病菌菌株进行了DNA分子指纹扩增和聚类分析,共获得73个不同的DNA指纹图谱(单元型)和62条分子量不等的DNA带型.结果显示,无论以何种遗传相似水平划分,四川稻瘟病菌的群体结构都表现很突出的优势宗谱,又存在着具有较多遗传多样性的次要小宗谱和特异性宗谱,蕴含着极其丰富的遗传信息;在0.19遗传相似水平,所有供试菌株可以划分成37个遗传宗谱,层次较为丰富.四川稻瘟病菌群体结构具有明显的时空特点,不同年度间稻瘟病菌群体存在一定的亲缘关系,又各自拥有当年的特异性宗谱;在空间上,不同稻作区表现出从复杂到简单的病菌群体变化特点.稻瘟病菌的遗传宗谱与生理小种致病型不存在一一对应的关系,作者认为将二者横向比较没有可比性.

Population genetic structure and its variation of rice blast fungus in long-grained nonglutinous rice growing regions in Sichuan

One hundred and thirty-seven isolates of rice blast fungus collected from six long-grained nongluti- nous rice-growing regions in Siehuan Province of China were analyzed for DNA polymorphism by using rep- PCR technique.There were 73 different DNA fingerprints (haplotypes),62 different DNA bands and 37 ge- netic lineages at 0.19 similar linkage distance level.The results showed that the rice blast population of Si- chuan included predominant lineages and many small and distinctive diversified lineages,which indicated plenty of genetic information among them.Furthermore,the rice blast population in Sichuan was exhibited ob- vious spatial and temporal characteristics,and in three years all isolates exist relative relationship and special lineages for each year while in different rice-growing regions they changed from relative simple to complicate. The rice blast population was closely related to the host genetic background and no distinctive correlation with pathotypes.It was no meaning with genetic lineages in contrast to pathotypes so far.