福建省马铃薯黑胫病病原菌的鉴定及其遗传多样性分析

Identification and analysis of genetic diversity of the pathogen causing potato blackleg disease in Fujian Province

为明确福建省马铃薯黑胫病病原菌的种类、分布情况及群体遗传特性,通过16S rDNA序列分析法对分离自福建省各马铃薯产区的90株黑胫病病原菌进行鉴定,并利用细菌基因组重复序列PCR(repetitive sequence-PCR,Rep-PCR)方法分析福建省不同地区的马铃薯黑胫病病原菌群体的遗传变异情况。结果表明,经16S rDNA序列分析鉴定,引起福建省马铃薯黑胫病的病原菌包括黑腐果胶杆菌Pectobacterium atrosepticum、胡萝卜果胶杆菌巴西亚种P.carotovorum subsp.brasiliense、胡萝卜果胶杆菌胡萝卜亚种P.carotovorum subsp.carotovorum、帕曼蒂氏果胶杆菌P.parmentieri、P.polaris和达旦提狄基氏菌Dickeya dadantii。对90株菌株的Rep-PCR检测得到47多态性条带条,多态性比率为100.00%。按采集地区将菌株划分为8个群体,其等位基因数平均为1.48,有效等位基数平均为1.30,Nei’s基因多样性指数平均为0.17,Shannon信息指数平均为0.26,多态性位点数平均为22.75,多态性位点百分率平均为48.40%。供试90株菌株之间的相似系数为0.584~1.000,遗传距离为0.149~0.602,群体遗传距离和地理距离之间无显著相关性。聚类分析结果表明当相似系数为0.605时,可将90株菌株分为4个类群,其中93.33%的菌株分布在Ⅰ和Ⅱ类群中,当相似系数为0.646时,第Ⅰ类群可分为2个亚群,第Ⅱ类群可分为3个亚群。表明福建省马铃薯黑胫病病原菌群体存在丰富的遗传多样性,Rep-PCR技术可用于其遗传多样性分析。

In order to characterize the distribution and population genetics of the pathogens causing potato blackleg disease in Fujian Province,90 isolates were obtained from diseased samples collected from potato producing areas in Fujian,and identified based on 16S rDNA sequence analysis,and the genetic diversity was analyzed using the Rep-PCR molecular markers.The results showed that the pathogens causing potato blackleg disease included Pectobacterium atrosepticum,P.carotovorum subsp.brasiliense,P.carotovorum subsp.carotovorum,P.parmentieri,P.polaris and Dickeya dadantii.The results from the analysis of Rep-PCR molecular markers showed that 47 polymorphic loci were detected in 90 strains,and polymorphism ratio was 100.00%.According to the collection areas,the tested strains were divided into eight groups,which the number of alleles was 1.48,the effective number of alleles was 1.30,the Nei’s diversity index was 0.17,Shannon information index was 0.26,the number of polymorphic sites was 22.75,and the percentage of polymorphic loci was 48.40%.The Nei’s genetic similarity was 0.584-1.000 among the 90 strains,and the genetic distance was 0.149-0.602.There was no significant correlation between genetic distance and geographic distance.The dendrogram analysis showed that at a genetic similarity coefficient of 0.605,90 strains could be divided into four groups with more than 93.33%of the strains were distributed in groups Ⅰ and Ⅱ.At a genetic similarity coefficient of 0.646,group Ⅰ could be further divided into two subgroups,and group Ⅱ could be divided into three subgroups.This study suggested that there was a rich genetic diversity in the potato blackleg pathogen population in Fujian Province of China,and the Rep-PCR can provide an effective tool for the study of genetic diversity in potato blackleg pathogen populations.