不同来源番茄溃疡病菌致病力差异研究

采用打顶法接种、半选择性培养基再分离发病植株中的病原菌，以及特异性PCR验证方法，对来自3个国家9个不同地区的46株番茄溃疡病菌进行了致病性测定，以病情指数评价不同菌株的致病力。结果显示，分离自我国河北滦平县、内蒙古包头市等地的24株菌株的病情指数达到75以上，属于强致病力水平；11株菌株的病情指数为50~75，属于中等致病力；而9株菌株的病情指数为50以下，属于弱致病力；检测同时证实，有2株属于无致病力菌株。强致病力、中等致病力、弱致病力和无致病力菌株占供试菌株总数的比例分别为52.2%、23.9%、19.6%和4.3%，表明供试的46株番茄溃疡病菌存在不同程度的致病力差异。

Pathogenicity testing for different strains of Clavibacter michiganensis subsp.michiganensis

The pathogenicity of 46 strains of Clavibacter michiganensis subsp.michiganensis(Cmm),isolated from 9 regions of 3 countries.were tested on tomato seedlings by means of top pruning with inoculation.The bacteria were re-isolated from the infected tomato seedlings by semi-selective medium mSCM and double checked by specific PCR.The results,based on the disease index to assay the pathogenicity difference of tested Cmm strains,showed that 24 of the 46 strains,isolated from Luanping County,Hebei Province and Baotou City,Inner Mongolia,were highly virulent,11 strains moderately virulent,9 strains weakly virulent and the other 2 strains were nonpathogenic.The percentage of each of these four strains were 52.2%,23.9%,19.6%and 4.3%,respectively.The data indicated that forty-six strains of Cmm exhibited significant pathogenicity differences.