中国大豆疫霉菌群体遗传结构的RFLP分析

 【目的】分析中国大豆疫霉菌的群体遗传结构，探索不同地区大豆疫霉菌群体间的亲缘关系。【方法】采用RFLP（restriction fragment length polymorphism）技术，对大豆疫霉菌进行群体遗传结构的分析；利用Popgene V1.32软件计算大豆疫霉菌群体间的遗传相似度；利用NTSYSpc V2.10软件估算菌株间的遗传距离，并依据遗传距离构建UPGMA（unweighted pair-group method with arithmetic averages）系统树状图谱。【结果】采用探针PS127558对来自黑龙江、新疆和内蒙古等5个大豆疫霉菌地理群体的133个菌株的遗传多样性进行了分析，共得到25条杂交带，其中多态性条带为24个，占96%。黑龙江分别和新疆、内蒙古群体间遗传相似度较高。相对于黑龙江群体遗传结构的高度复杂性，新疆和内蒙古菌株的群体遗传结构则比较简单，分别有88.2%和100%的菌株分属于同一聚类组，且均有超过58%的菌株和部分黑龙江菌株指纹图谱完全相同。Shannon’s多样性指数也表明黑龙江群体的遗传多样性最为丰富。福建和其它群体之间的遗传相似度较低，且分别有45.5%和54.5%的福建群体都属于聚类组E和F，遗传背景较为单一。福建群体的Shannon’s多样性指数低于黑龙江和美国。美国和黑龙江群体之间的遗传相似度较高，且部分美国菌株和黑龙江菌株指纹图谱相同。【结论】新疆、内蒙古的大豆疫霉菌起源于黑龙江，福建的大豆疫霉菌可能为一个独立的进化分支或起源于其它地区。此外，中国和美国的大豆疫霉菌群体间存在菌源交流。

Genetic Diversity of Phytophthora sojae in China Based on RFLP

【Objective】 The objective of this study is to explore the genetic diversity among Phytophthora sojae strains from soybean-growing regions in China and America. 【Method】 Restriction fragment length polymorphism (RFLP) was used to examine the genetic relationships among strains of P. sojae collected from 5 different regions. Nei’s genetic distances among the strains of P. sojae were calculated, and cluster analysis using UPGMA method was carried out by using the software package NTSYSpc V2.10. The Popgene V1.32 was used for calculation of genetic identity. 【Result】 RFLP probe PS127558 was selected and 25 fragments were detected, of which 24 was polymorphic, leading to the identification of 2 multilocus RFLP groups amongst the strains from Xinjiang and Inner Mongolia. RFLP group A which also exists in Heilongjiang occurred in over 88.2% of all samples collected from Xinjiang and 100% from Inner Mongolia, respectively. Genetic identity among populations of Xinjiang and Heilongjiang or Inner Mongolia and Heilongjiang is very high. Shannon’s information index revealed that the Heilongjiang populations have a higher genetic diversity than that of the Xinjiang and Inner Mongolia ones. RFLP probe PS127558 detected 17 fragments and 12 of which were polymorphic, among the 22 Fujian P. sojae strains, which lead to the distinction of 2 multilocus RFLP groups. Genetic identity is very low among the populations of Fujian and any of the other regions. The P. sojae strains between Heilongjiang and America show a high level of genetic identity, and several strains with shared DNA fingerprints were also found between Heilongjiang and America.【Conclusion】 P. sojae in Xinjiang and Inner Mongolia might have been introduced from Heilongjiang, and that in Fujian might belong to a separate evolutionary branch or originated from other area. In addition, exchange of P. sojae strains also occured between Heilongjiang and America.