【作者】 徐陈贤；

【导师】 王克荣；

【作者基本信息】 南京农业大学 ， 植物病理学， 2003， 硕士

【摘要】 本研究以栗疫病菌(Cryphonectria parasitica)为实验材料，进行栗疫病菌及其dsRNA的群体多样性研究。 采用生物学测定和凝胶电泳对栗疫病菌的dsRNA进行研究。根据电泳图谱，中国东部栗疫病菌的dsRNA可以分为4种类型，其中类型1只具有一个12.7kb的条带，占大多数；类型2有两条带，一条12.7kb，另一条10kb左右，类型3则除了12.7kb的条带外，还有2～3条小于2kb的小片段，类型2和3各有4个和3个菌株；只有一个菌株的dsRNA属于类型4，它含有两个1～2kb的小片段。这些含有dsRNA的菌株在培养性状上差异明显，可以划分为五种培养类型。菌株的培养类型与dsRNA的类型没有对应的关系。毒力测定表明含有dsRNA病毒的供试菌株间的毒力有一定差异。 从120个随机引物中筛选出条带清晰、主带明显、重复性好的9条引物，对来自中国江苏、北京、辽宁、福建及意大利、日本、美国的7个群体共113个栗疫病菌进行RAPD分析。共扩增出条带124条，其中多态性条带111条，多态性比率为89.52％。利用Popgen3.2软件对供试群体进行遗传多样性分析和UPGMA聚类。结果表明，中国地区4个群体间的遗传相似性较大，与美国、意大利和日本群体间的相似性较小；美国和意大利群体间的遗传相似性较大，且它们与日本群体间的相似性大于与中国群体间的相似性。在地区水平上，病原菌群体的遗传变异率为0.2351，其中82.34％由群体内的变异引起，17.66％由群体间的差异引起，群体间的基因流动值为2.3311；在寄主水平上，则是79.42％由群体内的变异引起，20.58％由群体间的差异引起，群体间的基因流动值为1.9297。更多还原

【Abstract】 The population diversity of chestnut blight fungus, Cryphonectria parasitica and its double strand RNA were studied in this thesis.dsRNA virus of Cryphonectria parasitica was studied by use of biological assay and gel electrophoresis. dsRNA viruses of C. parasitica from east of China were divided into 4 types on the basis of electrophoresis patterns. Type 1 has only one segment of 12.7kb, accounting for majority of the total isolates. Type 2 has another large segment about 10kb besides the segment of 12.7kb, containing 4 isolates. Type 3 has 2 or 3 small segments shorter than 2kb other than the segment of 12.7kb, containing 3 isolates. Only 1 isolate belonged to type 4, it has 2 small dsRNA segments about l~2kb. The cultural character of all these tested isolates were various and divided into 5 cultural types. Cultural type of C. parasitica is not consistent with the type of dsRNA. Virulence test results showed there was certain difference betweenthe isolates containing dsRNA.A total of 113 isolates of C. parasitica from 7 populations, viz. Jiangsu, Beijing, Liaoning, Fujian, Italy, Japan and America, were amplified with 9 RAPD primers which were selected from 120 ramdom primers. 124 RAPD fragments were obtained and 89.52% of them were polymorphic. Genetic diversity and UPGMA dendrogramwere analysed by use of Popgen3.2. The results showed that 4 populations in China were more similar to each other, than to populations in Italy and America; America and Italian populations were similar to each other, and more similar to Japanese than to Chinese. Gene diversity was decomposed hierarchically. At region level, the gene diversity of the total population was 0.2351, 82.34% of gene diversity was attributedto diversity within populations, compared to 17.66% among populations, the gene flow estimate among populations was 2.3311. While at host level, the gene flow value was 1.9297, with 79.42% of gene diversty attributable to diversity within populations and 20.58% among populations.更多还原