国内木薯主产区细菌性枯萎病病原鉴定

Pathogen identification of cassava bacterial blight from several main cultivation area in China

细菌性枯萎病是当前我国木薯生产中的第一大病害。开展了不同主产区病原菌的分离鉴定工作,以期为相关防控技术的研发提供基础。田间采集典型病叶后采用组织块分离法进行病原菌的分离,所获菌株经致病性评价后,进行生理生化特性测定、16S rDNA和pthB基因序列分析。从广西、海南、广东获得3株病原菌,接种木薯叶片后均形成和田间症状类似的病斑,培养性状观察和生理生化特性测定表明3个菌株均为地毯草黄单胞杆菌(Xanthomonas axonopodis)。16S rDNA序列分析表明其和柑橘溃疡病菌(AE008923,DQ991194)、辣椒斑点病菌(AM039952)等的同源性在99%以上。各菌株均获得和已报道木薯细菌性枯萎病菌pthB基因序列完全一致的扩增片段。致病性评价、生理生化特性测定、16S rDNA和pthB基因序列分析等结果表明所获菌株均为地毯草黄单胞杆菌木薯萎蔫致病变种(Xanthomonas axonopodis pv.manihotis)。

Bacterial blight is the most serious disease in the cassava plantations of China. In our research, the pathogens from different main cultivation area were identified in order to lay the foundation for research and development of prevention and control technology related. The typical disease leaves were collected in field, and the pathogens were separated by tissue isolation method. When the pathogenicity test was finished, physiological and biochemical characteristics, sequence analysis of 16S rDNA and pthB gene were carried out. Three strains from Guangxi, Hainnan and Guangdong were obtained in our research. The similar lesions were formed on the leaves when the pathogens were inoculated, which were similar with disease leaves in field. The results of cultural characters observation, physiological and biochemical characteristics showed three strains were Xanthomonas axonopodis. The sequence analysis of 16S rDNA showed the homologies of these strains were more than 99% with Xanthomonas campestris pv. citri （AE008923, DQ991194）, Xanthomonas campstris pv. vesicatoria （AM039952）. The same sequences with pthB gene of Xanthomonas axonopodis pv. manihotis strain reported were obtained too. Three strains obtained in our research were identified as Xanthomonas axonopodis pv. manihotis.