进境菜豆种子中普通细菌性疫病菌的分离和鉴定

Isolation and identification of Xanthomonas axonopodis pv. phaseoli in imported bean seed lots

对经甘肃口岸进境的30批菜豆Phaseolus vulgaris种子进行了普通细菌性疫病菌的检测,利用选择性培养基MT从波兰进境菜豆种子上分离到1株细菌597,对该分离物进行菌落形态特征观察、致病性测定、16S rDNA及16S-23S rDNA ITS序列分析和特异性PCR检测。结果表明,该分离物在MT培养基上菌落呈黄色、圆形、黏稠、表面光滑向外隆起、菌落周围有水解圈。分离物597接种菜豆幼苗后导致叶片枯萎,接种点干枯。结合菌落形态、16S-23S rDNA ITS序列、特异性PCR检测结果,将分离物597鉴定为地毯草黄单胞杆菌菜豆致病变种Xanthomonas axonopodis pv.phaseoli。

A bacterial strain 597 was intercepted in bean seeds imported from Poland with semi-selective media milk tween agar (MT), and detected by the morphological characteristics, pathogenicity, 16S rDNA sequence analysis, 16S-23S rDNA ITS sequence analysis and PCR detection.Colonies of the bacterium were yellow, mucoid and convex on MT medium and zones of hydrolysis formed around them. The pathogenicity test showed that the strain 597 caused typical leaf wilting of bean by artificial inoculation. 16S-23S rRNA ITS sequence analysis indicated that the strain shared 100% sequence identity with X. axonopodis pv. phaseoli in GenBank. The result of PCR showed that the strain 597 could be detected by X. axonopodis pv. phaseoli- specific primers X4c/X4e, XA5F/XA5R, XC9F/XC9R, XC12F/XC12R, and XO4F/XO4R. The strain 597 was identified as X. axonopodis pv. phaseoli .