台湾柠檬上柑橘溃疡病菌的分离鉴定

Isolation and identification of Xanthomonas axonopodis pv.citr on lemon samples from Taiwan

从送检台湾柠檬样品上发现疑似柑橘溃疡病病斑,对病原菌进行了分离纯化,并且通过形态学特征观察、致病性测定、特异性引物扩增和gyr B序列比对分析,对其进行了鉴定。结果显示,菌株6503在NA培养基上菌落呈黄色,圆形,全缘,有光泽,微隆起,黏稠;致病性测定结果显示,分离物6503能够导致柑橘叶片产生明显的溃疡病斑;柑橘溃疡病菌种特异性引物Xac01/Xac02从菌株6503的DNA中扩增得到581 bp的特异性条带;基于gyr B序列构建的系统发育树中6503和柑橘溃疡病菌处于同一分支,亲缘关系最近。根据试验结果,菌株6503被鉴定为柑橘溃疡病菌。

A typical symptom of citrus bacterial canker was observed on inspection of lemon samples imported from Taiwan. A strain 6503 was isolated from this sample and was identified by morphological observation,pathogenicity determination,specific-PCR detection and gyr B sequence analysis. The colony morphology of strain 6503 on nutrient agar medium（NA） was yellow,circular,entire,glistening,convex,mucoid. The pathogenicity test demonstrated that strain 6503 was pathogenic to the leaf of citrus. Strain 6503 can be amplified and produced 581 bp target band with specific primer Xac01/Xac02. Strain 6503 and X. axonopodis pv. citri were within the same clade in phylogenetic tree based on gyr B sequences. Based on these results above,strain 6503 was identified as X. axonopodis pv.citri.