广东茄科青枯菌致病力分化及其DNA多态性分析

Differentiation of pathogenicity and RAPD analysis of Ralstonia solanacearum in Guangdong

分别采自广州、增城、东莞、花都、三水、清远、电白、高要 8个菜区的番茄、茄子和辣椒上的 31个青枯病菌株 ,经人工接种于 10个鉴别寄主植物上 ,结果表明 ,它们的致病力存在明显的差异。聚类分析这 31个菌株 ,可以聚为 3个组 :第I组菌株主要来自种植番茄和茄子历史较长的广州、东莞、增城老菜区 ,其致病力较强 ;第II组菌株主要分离自茄子和辣椒上 ,其致病力中等 ;第III组菌株主要来自近年来新发展的三水市各番茄产区 ,它们的致病力较弱。从 2 0 0个随机引物中筛选出 17个引物用于上述 31个菌株DNA的RAPD分析 ,共扩增出 5 2 3条带 ,其中 4 6 8条为多态性带 ,占 89.5 %。聚类分析这 31个菌株 ,又可聚为 4个簇群 :第I簇群主要分离自已推广种植多年的丰顺、金丰等抗病番茄品种上 ;第II簇群分离自抗病的番茄新品种新星、年丰和石碣紫红茄上 ;第IV簇群主要分离自辣椒和茄子 ;而第III簇群来源包括番茄、茄子和辣椒这 3种寄主植物。上述试验结果说明 ,广东茄科青枯菌的致病力存在明显的分化现象 。

The pathogenicity of 31 isolates of Ralstonia solanacearum from tomato, eggplant and capsicum in Guangzhou, Zengcheng, Dongguan, Huadu, Sanshui, Qingyuan, Dianbai and Gaoyao was identified on 10 differential host plants. The results revealed an obvious diversity of their pathogenicity. Cluster analysis based on the data of disease incidences suggested that these bacterial isolates might be divided into three groups. The isolates of group I that showed the strongest virulence were distributed in Guangzhou, Zengcheng and Dongguan where tomato and eggplant had been grown for many years. The isolates of group II were mainly collected from eggplant and capsicum plants and showed the moderate virulence. The members of group III which showed the weak virulence were mainly distributed in Sanshui, a new tomato-growing area developed in recent years. The genetic diversity of 31 isolates of R. solanacearum was assessed by RAPD with 17 primers selected from 200 random primers.A total of 523 bands were scored.The frequency of genetic diversity was 89.5%. The cluster analysis based on the RAPD bands showed that 31 isolates could be separated into 4 clusters. The isolates of cluster I were mainly collected from the resistant varieties, such as Fengshun and Jinfeng, which had been grown for many years. The isolates of cluster II were collected from new resistant tomato varieties Xinxing and Nianfeng and eggplant variety Shijie. The isolates of cluster IV were mainly collected from capsicum and eggplant plants. The host plants of the cluster III included tomato, eggplant and capsicum. It is thus concluded that there exists obvious differentiation of the pathogenicity of R. solanacearum in Guangdong, and that there exists genetic diversity within the 31 isolates of R. solanacearum.