我国植物青枯菌菌株的遗传多样性和组群划分

RAPD analysis and group division of Ralstonia solanacearum strains in China

采用15条随机引物对我国11个省(市、区)6种不同寄主植物的43个青枯菌代表性菌株和4个国外青枯菌菌株,进行了PCR扩增。引物OPB11、OPA15、OPE1和OPZ10对上述所有菌株扩增获得了相似的产物电泳图谱,分别具1～5条谱带不等;引物OPB7、OPA10和OPF1对马铃薯菌株获得了相同的产物图谱,但对其它寄主菌株的产物间有明显差别;引物OPA14、OPG6、OPG14、OPF5、OPK14、OPK20和OPK17对于不同菌株的扩增产物多态性很强。供试菌株被聚类为2个组群,即组群A和组群B。组群A中又可分为7个亚组(A1、A2、A3、A4、A5、A6、A7),其中A1含有2个类型(A1-1、A1-2);组群B中也可分为2个亚组(B1、B2),其中B1含有3个类型(B1-1、B1-2、B1-3),B2也含有3个类型(B2-1、B2-2、B2-3)。RAPD组群A中包含了27个来自我国不同地区的马铃薯菌株,主要是3号小种、生化变种2;组群B中含有20个来自不同地区、不同寄主的菌株,分属于其它不同的小种和生化变种。研究结果表明,我国青枯菌菌株RAPD组群的划分与菌株的地理来源关系不大,而与寄主来源有明显相关性。此外,通过对我国青枯菌菌株组群进行同源性PCR分析表明,来源自马铃薯的3号小种菌株属于美洲分支“Americanum”,而来自其它寄主的青枯菌1号、5号小种菌株属于亚洲分支“Asiaticum”。

Forty-three representitive strains of R. solanacearum collected from 11 Provinces or regions on 6 different plant hosts in China and 4 strains Obtained from other countries were detected by PCR using 15 random primers. Similar DNA fingerprints were obtained by using primers OPB11, OPA15, OPE1 and OPZ10. Potato strains showed identical profiles when primers OPB7, OPA30 and OPF1 were used. High level diversity was found among different strains in the case of using primers OPA14, OPG6, OPG14, OPF5, OPK14, OPK20 and OPK17. Two groups (A, B) were clustered from RAPD data. Group A could be divided into 7 subgroup (A1, A2, A3, A4, A5, A6, A7), and furthermore A1 involved 2 types (A1-1, A1-2). Group B could be divided into two subgroups (B1, B2) which contained three types (B1-1, B1-2, B1-3; B2-1, B2-2, B2-3) respectively. RAPD group A included 27 potato isolates from different locations, and they were mainly belonging to race 3 (biovar 2). Group B consisted of 20 isolates belonging to races 1 and 5 from different locations and plant hosts. RAPD groups in this study are not related to location sources but closely reated to hosts. The geographical origin of R. solanacearum strains in China was preliminarily analyzed by PCR. Isolates of potato race 3 were belonging to American division' Americanum' , whereas other isolates were belonging to Asian division 2' Asia- ticum'. These results are coincided to RAPD grouping.