四川省草莓主产区灰葡萄孢菌的遗传多样性

Genetic diversity of Botrytis cinerea in major strawberry-growing regions of Sichuan Province

为明确四川省草莓灰葡萄孢Botrytis cinerea群体遗传结构及其多样性水平,采用ISSR分子标记技术对分离自四川省10个县(市)的195株灰葡萄孢菌进行了遗传多态性分析。结果表明,四川省灰葡萄孢菌多态性丰富,6条ISSR引物共产生了63个多态性位点,应用Popgene32软件计算四川省不同主产区域(除德阳广汉种群外)种群的Nei’s基因多样性指数(H)和Shannon信息指数(I)均达到了H>0.2、I>0.3的水平,表明四川省的灰葡萄孢菌具有丰富的遗传多样性;灰葡萄孢菌群体的遗传多样性(Ht)均值为0.2976,种群内遗传多样性(Hs=0.2458)远远高于种群间(Dst=0.0518)的遗传多样性;遗传分化系数(Gst)均值0.1742,基因流(Nm)均值2.3696,说明该地区灰葡萄孢菌种群间遗传分化不明显,群体内基因交流频繁。通过UPGMA法和Omishare Tools热图软件均可将10个采集点分为3个类群,来自绵阳江油的菌株单独构成一个类群,来自成都崇州和德阳广汉的菌株构成一个类群,其余的菌株构成另外一个类群;利用Structure2.3软件对195份灰葡萄孢菌进行群体结构分析,可将134份菌株划分成21个群,另外61个菌株被列为混合群体。

A total of 195 isolates of Botrytis cinerea was investigated through inter-simple sequence repeat(ISSR) markers with six ISSR primers to determine its genetic structure and diversity in Sichuan Province. The results showed that the pathogen was genetically polymorphic and generated 63 polymorphic loci(96.83%).By using Popgene32 software, the Nei’s gene diversity index(H) and Shannon information index(I) were H>0.2 and I>0.3 respectively, showing rich genetic diversity of B. cinerea in Sichuan Province, except for population of Deyang in Guanghan region. The average genetic diversity(Ht) index was 0.2976. The diversity index of intrapopulations(Hs=0.2458) was much higher than that of interpopulations(Dst=0.0518). The average genetic discrepancy coefficient(Gst) and average gene flow(Nm) reached 0.1742 and 2.3696 respectively,indicating that there was no obviousness in genetic differentiation of B. cinerea inter populations, but gene exchange frequently occurred within populations. The isolates of B. cinerea from ten main strawberry-growing regions in Sichuan Province could be divided into three geographical groups based on UPGMA and Omishare Tools thermogram analysis. The isolates from Jiangyou were clustered in the first group, those from Chongzhou and Guanghan in second group, while the remainder in the third group. Population structure analysis by using software 2.3 showed that 195 isolates of B. cinerea were clustered into 21 groups composed of 134 isolates and the other 61 isolates were regarded as mixed group.