稻瘟病菌群体的分子遗传学研究II.广东省2000年度稻瘟病菌群体遗传结构的时空特性

MOLECULAR GENETIC STUDIES ON THE RICE BLAST FUNGUS POPULATION II. TEMPORAL AND SPATIAL CHRACTERIZATION OF GENETIC STRUCTURE OF THE FUNGUS POPULATION IN 2000 IN GUANGDONG PROVINCE

利用随机扩增多态性DNA技术对广东省2000年度稻瘟病菌群体的遗传结构进行了分析。以相似性系数为0.62阀值时,可将采集于广东省三大生态稻作区、早稻和晚稻生长季节的104个菌株划分为14个遗传宗谱;其中宗谱5和宗谱8的菌株数各占总数的25%,为优势宗谱;宗谱4和12的菌株数各占总数的14.4%和9.6%,为亚优势宗谱;其余的29个菌株,分别归属于其它10个宗谱,其中有5个宗谱是单菌株宗谱。本年度稻瘟病菌群体的遗传结构呈现明显的区域性特性:遗传结构呈由北向南多样化的趋势;各个稻作区甚或亚区有其特异性的宗谱。本年度稻瘟病菌群体的遗传结构也显示分明的生长季节特性:来源于早稻和晚稻生长季节的菌株完全分属于宗谱图的上下两个半区,彼此之间不存在共同的宗谱;而且后者的遗传宗谱要比前者的复杂、多样。研究还表明,虽然稻瘟病菌群体的遗传结构2000年度与1998-1999年度的比较存在较大的差异,但是两者仍然具有良好的相承性和可比性。如何进一步验证和把握稻瘟病菌群体的遗传结构所表现出的时空特性是值得我们进一步探讨的重要课题。

Genetic structure of the rice blast fungus population in 2000 in Guangdong Province, China was assessed with RAPD (random amplified polymorphic DNA) markers. 104 isolates collected from three rice-growing regions in early and late seasons in 2000 were divided into 14 genetic lineages drew by unweighted pair group method using arithmetic average (UPGMA) when focused at the similarity coefficient of 0.62. Among the 14 genetic lineages, lineages 5 and 8 both consisted of 26 isolates were recognized as dominant lineages in 2000. Spatial characterization of the genetic structure showed that there is a tendency to increase the genetic diversity from northern to southern regions in Guangdong, and each region has its own specific lineages. Temporal characterization of the genetic structure suggested that there is also a tendency to increase the genetic diversity from early to late seasons in Guangdong, and two major groups corresponding to the two seasons were distinct with similarity coefficient of 0.50. The temporal and spatial characterizations represent in 2000 were similar to those represented in 1998-1999, even though the genetic structures of the populations between 1998-1999 and 2000 were considerably different.