稻瘟病菌群体的分子遗传学研究——由5个亚群体组成的广东省稻瘟病菌群体遗传结构的分析

Molecular Genetic Studies on the Rice Blast Fungus Population——Genetic Structure of the Rice Blast Fungus Population Consisted of Five Sub-populations Selected from Five Counties in Guangdong Province, China

为了从不同角度和手段来了解稻瘟病菌群体遗传结构的特征 ,笔者利用一种新型的PCR标记SRAP(se quence relatedamplifiedpolymorphism)对广东省 2 0 0 0和 2 0 0 1年度 5个地点的稻瘟病菌亚群体组成的试验群体的遗传结构进行了描述 ;进而计算各个亚群体的宗谱频率和特异性宗谱频率 ,对各个亚群体的遗传多样性和特异性进行了比较分析。从稻作区层面来看 ,本试验群体的遗传结构呈现南北分离、中间交汇的区域性特征 ;粤北稻区的遗传特异性明显地高于粤中稻区和粤南稻区。从供试地点层面来看 ,5个供试亚群体之间的遗传多样性和特异性存在较大的差异 ,即便是同为粤北稻区的乳源县和仁化县、以及粤南稻区的信宜县和廉江县 ,亚群体之间也存在较大的差异。从年份层面看 ,2个年度供试亚群体之间的遗传多样性和特异性极为相似。从生长季层面来看 ,2个生长季节供试亚群体间的遗传多样性和特异性也较相似。试验结果表明 ,以较小地理范围选择和构成的试验群体 ,是从不同角度深入地了解稻瘟病菌群体遗传结构特征的有效途径之一。

Genetic structure of the rice blast fungus population , which consists of five sub-populations selected from five counties in Guangdong Province (GD), China, in 2000 and 2001, was studied by DNA fingerprinting with a new PCR (polymerase chain reaction)-based molecular marker system, SRAP (sequ ence-related amplified polymorphism). Genetic diversity and specificity of sub -population were evaluated by the frequencies of lineage and specific lineage, respectively. As for the rice-growing regions, there is no any common lineage b etween North and South regions, whereas there are some lineages in the Middle re gion, which are common to those in North or South regions, and genetic specifici ty of North GD is higher than those of other two regions. As for the counties, g enetic diversities and specificities of five sub-populations tested were certai nly different, even in the same rice-growing regions. However, genetic diversit ies and specificities responsible to two rice-growing years as well as seasons were similar with one another. The results from this study suggested that the ex perimental population consisted of sub-populations constructed from micro-geog raphical scale might be a complementary way to dissect genetic structure of the rice blast fungus population.