不同供氮水平下水稻稻瘟病菌群体遗传结构的SSR分析

SSR Analysis for Magnaporthe grisea Populations influenced by Nitrogen Application Levels

研究不同供氮水平对稻瘟病菌群体遗传多样性和遗传结构的影响。用11对SSR引物对180 kg N/hm2(N180)和300 kg N/hm2(N300)下水稻黄壳糯的35个稻瘟病菌株进行遗传多样性分析。结果表明:在N300和N180两施肥水平下,稻瘟病菌居群的平均等位基因数分别为4.3636和2.9091,Nei′s基因多样性指数分别为0.6497和0.462 4,Shannon′s信息指数基因分别为1.2206和0.7853。两个群体间的遗传相似系数为0.6337,遗传距离为0.4561,基因分化系数为Gst=0.1355,表明居群间有一定分化。用UPGMA方法聚类可知,在45%的相似水平上,稻瘟病菌被划为8个宗群,N300条件下分离的稻瘟病菌株较N180占有更多的宗群,表明N300条件下分离的稻瘟病菌株较N180具有更丰富的遗传多样性。

Genetic variation and genetic structure of Magnaporthe grisea under different nitrogen （N） application levels were investigated in this article. The genetic diversity of 35 Magnaporthe grisea isolates of rice （Huangkenuo） under 180 kg N/hm^2 （N180） and 300 kg N/hm^2 （N300 ） were analyzed using 11 pairs of SSR primers. The results showed that under 2 N - application levels （ N300 and N180 ）, observed numbers of alleles of Magnaporthe grisea Populations were 4. 363 6 and 2. 909 1, respectively, Net＇s gene diversity index were 0. 649 7 and 0. 462 4, respectively, and Shannon＇s information index were 1. 220 6 and 0. 785 3, respectively. The genetic identity and distance between the 2 populations were 0. 633 7 and 0. 462 4, Gst was 0. 1355, indicating that there was some differentiation between populations. All isolates were classified into 8 genetic lineages at 0. 45 level of the genetic identity through the clustering analysis of UPGMA, in comparison with genetic lineages of N180, Magnaporthe grisea isolates hold more lineages under the N300 level, indicating that there have richer genetic diversity under the N300 level than under the N180 level.