甘肃省甘蓝黑腐病的病原分离及鉴定

Isolation and Identification of the Pathogen Causing Black Rot of Cabbage in Gansu Province

为明确甘肃省张掖市甘蓝黑腐病的病原菌种类,采用平板划线法对采集到的甘蓝典型发病叶片进行病原菌分离、致病性测定及基因序列分析鉴定。结果表明,从具有典型黑腐病的甘蓝叶片上分离纯化获得6个分离株,其中菌株GL3-2为引起该病害的病原菌,为革兰氏阴性菌,菌落近似圆形,初呈淡黄色,后渐变为蜜黄色,菌落边缘整齐光滑,有隆起,且具光泽;菌体多呈短杆状,大小为(0.5~1.0)μm×(1.0~3.0)μm,无芽孢,单生或链生。根据培养性状、形态特征以及16S rDNA和特异性基因序列分析,确定致病菌菌株GL3-2为野油菜黄单胞菌野油菜致病变种(Xanthomonas campestris pv.campestris)。

To clarify the pathogen causing cabbage black rot in Zhangye City,Gansu Province,the cabbage leaves with typical disease symptoms were collected for pathogen isolation,purification by using plate scribing method.The pathogenicity was determined,and pathogen also was identified by morphological characteristics and molecular biology methods.The results showed that 6 isolates were obtained,among which GL3-2,Gram-negative,was pathogenic bacteria.Its colony was round,light yellow at first,and then honey yellow gradually.The colony edges were neat,smooth,and glossy;Most of the bacteria were short rods with the size of(0.5 to 1.0)μm×(1.0 to 3.0)μm.No spores,solitary or chained,extremely solitary flagella.GL3-2 was identified as Xanthomonas campestris pv.campestris based on culture traits,morphological characteristics,16S rDNA and specific genes sequence analysis.