【作者】 侯晓强；

【导师】 董金皋；

【作者基本信息】 河北农业大学 ， 植物病理学， 2004， 硕士

【摘要】 玉米大斑病是玉米上重要的叶部病害，病菌是异宗配合真菌，有性杂交有可能增强病菌的致病力，或形成新的致病小种，扩大病菌的寄主范围，但至今未发现有关证据。本文以亲本菌株132和135及其有性杂交产生的70个子囊孢子后代菌株为试材，进行了生理小种鉴定、AFLP分子多态性分析和酯酶同工酶多态性分析等研究，以期从遗传学角度分析玉米大斑病菌生理分化和遗传多样性的产生原因。 利用含不同抗性基因的玉米作为鉴别寄主，对两个亲本菌株132、135和它们的70个单子囊孢子后代菌株进行了生理小种的测定，结果表明，亲本菌株132为23N号小种，135为23号小种，在70个后代菌株中23N号小种占41.4％，23号小种占20.0％，除了这两个小种外，还出现了其他类型的生理小种，如0、1、2、3、13、123、12N、13N和123N号小种，它们在后代菌株中所占比例分别为2.9％、1.4％、2.9％、2.9％、4.3％、8.6％、1.4％、4.3％和10.0％。从而表明，子囊孢子后代的生理小种分化程度较大，其中出现的123N号生理小种对带不同Ht抗性基因的玉米均致病。 本试验利用AFLP技术对亲本和70个后代菌株的遗传多样性进行了研究，建立了适用于玉米大斑病菌的AFLP扩增反应体系和程序。利用该体系对供试菌株进行分子遗传多态性分析，发现后代菌株基于AFLP的分子遗传相似系数在0.87～0.99之间。其中59个后代菌株与亲本菌株的相似系数在0.878以上，占84.3％；和亲木菌株132相似的菌株为49个，占70.0％；和亲本菌株135相似的菌株为10个，占14.3％。结果表明，这与致病性遗传(41.4％后代菌株与132相同，20％后代菌株和135相同)相似。在基因重组的过程中，菌株132的遗传力强于135。 利用非变性聚丙烯酰胺凝胶电泳技术，对亲本和部分后代菌株进行酯酶同工酶多态性分析。结果表明，菌株间在酯酶同工酶水平上存在显著差异。亲本菌株和子囊孢子后代菌株在酯酶同工酶谱上共出现了9条谱带，其中有4条公共谱带，Rf值分别为0.256、0.684、0.786、0.923；5条明显的差异带，Rf值分别为0.111、0.291、0.342、0.496、0.855；这些条带共同组成了六种谱带类型。 对玉米大斑病菌亲本菌株和后代菌株的生理小种分化、AFLP分子遗传多态性分析及酯酶同工酶多态性进行了比较，发现生理小种分化和AFLP分子遗传多态性有一定的相关性，但不能完全对应，不存在简单的遗传谱系—小种一一对应关系。生理小种分化和酯酶同工酶多态性之间也不存在一一对应关系，同一酯酶同工酶带型中有不同的生理小种出现，在同一生理小种菌株中也有不同的酯酶同工酶带型的出现。更多还原

【Abstract】 Northern corn leaf blight is one of the important diseases in maize. The pathogen, Setosphaeria turcica, is heterothallic. It is predicted that the plant fungal pathogen can enhance its pathogenicity, change its pathogenic host range and generate new physiological races through sexual hybridization. Therefore, two parent isolates, 132 and 135, belonging to two opposite mating types and different races were chosen to study the pathogenic differentiation and genetic diversity in their progenies.Both parent isolates and their seventy progenies which belonging to which physiological races of S. turcica was identified using identification hosts. The results showed that the parent isolate 132 belonged to race 23N and the other parent isolate 135 belonged to race 23. About 41.1 percent and 20 percent progeny isolates were identified to be race 23N and race 23, respectively, but race 0, 1, 2, 3, 13, 123, 12N, 13N and 123N were also existed in these isolates tested. Race 123N, a pathogenic race to corn with all the known four resistant genes, should be paid more attention. The physiological differentiation in progeny isolates is diversity and broad.The fingerprinting analysis based on AFLP molecular marker was carried out and an effective AFLP technological system which was suitable for genetic analysis of S. turcica had been established. The results showed that similarity coefficient between isolates tested was from 0.87 to 0.99. Most of progeny isolates were similar to their parent isolates. Moreover, there were more progenies similar to parent isolate 132 compared to isolate 135. It indicated that the genetics of S. turcica was complex. Parent isolate 132 maybe had stronger genetic transmittal ability than parent isolate 135 in the course of sexual hybridization.The esterase isozyme polymorphism among the parent isolates 132 and 135 and their progenies were analyzed by polyacrylamide gel electrophoresis (PAGE). The results showed that there was great diversity in the esterase isozyme map among parent and progenies isolates. Four common bands were found among the total nine bands on the esterase isozyme map. Their Rf values were 0.256, 0.684, 0.786 and0.923, respectively. The other five bands are specific and their Rf values were 0.111, 0.291, 0.342, 0.496 and 0.855, respectively. These bands of esterase isozyme formed into 6 different patterns of isozyme bands.Through comparing the physiological differentiation, with AFLP molecular diversity and esterase isozyme polymorphism, it was found that the physiological differentiation and AFLP molecular genetic polymorphism were not definitely completely correlated. The physiological differentiation and esterase isozyme polymorphism were not correlated to some extents either.更多还原