广东省冬枣叶枯病病原菌的分离与鉴定

Identification of the pathogen causing Ziziphus jujuba Mill.cv.Dongzao leaf necrotic disease in Guangdong Province

2018年2月,广东省清远市冬枣种植区发生了一种叶枯病,发病率约为17%,严重影响植株生长。为明确引起广东省清远市冬枣叶枯病的病原,采用常规病组织分离法获得2株菌株,通过致病性、生理生化特征和分子生物学对2株菌株进行鉴定。致病性测定结果显示,该细菌可侵染引起冬枣叶片产生枯死症状,与田间病株的症状相同。生理生化测定结果显示,该病原菌为革兰氏阴性菌,在LB平板产生黄色菌落;除利用蜜二糖产酸结果不同,2株菌株与成团泛菌Pantoea agglomerans ATCC27155菌株的其他生理生化特征相同。系统进化分析结果表明,QYZ1和QYZ22株菌株的16S rDNA序列分别与P.agglomerans TH81(CP031649)菌株、P.agglomerans C410P1(CP016889)菌株、P.vagans FDAARGOS160(CP014129)菌株和P.vagans C9-1(CP002206)菌株的相似性在99%以上;多位点序列分析结果表明,QYZ1和QYZ2与P.agglomerans TH81菌株关系最近,聚在一个分支。生理生化特征及分子生物学鉴定结果表明,引起广东省冬枣叶枯病的病原为成团泛菌。本研究是成团泛菌引起广东省冬枣叶枯病在国内的首次报道。

In 2018,a new disease with necrotic symptoms affecting the leaves of Ziziphus jujuba Mill.cv.Dongzao was observed in Qingyuan city,Guangdong province,China.The disease incidence reached 17%in fields.In order to identify the pathogen of Ziziphus jujuba Mill.cv.Dongzao leaf necrotic disease in Qingyuan city,Guangdong province,two isolates of the pathogen were obtained by diseased tissue isolation method.Two isolates were identified by pathogenicity test,physiological and biochemical characteristics and molecular biological identification.The results of pathogenicity test showed that Ziziphus jujuba Mill.cv.Dongzao plants inoculated with the isolates of the bacterium could infect Ziziphus jujuba Mill.cv.Dongzao and caused the same symptoms as the diseased Ziziphus jujuba Mill.cv.Dongzao plants in the fields.The physiological and biochemical characteristics of QYZ1 and QYZ2 were same to that of Pantoea agglomerans ATCC27155 except for melibiose utilization.The results of phylogenetic analysis showed that 16 S rDNA gene sequences of two isolates share high identify of 99%with P.agglomerans TH81(CP031649),P.agglomerans C410 P1(CP016889),P.vagans FDAARGOS160(CP014129)and P.vagans C9-1(CP002206).The results of phylogenetic multilocus sequence analysis showed that QYZ1 and QYZ2 were clustered into a group with P.agglomerans TH81.The pathogen of Ziziphus jujuba Mill cv.Dongzao leaf necrotic disease was identified as P.agglomerans based on the results of physiological and biochemical characteristics and molecular biological identification.This is the first recorded report of necrotic disease caused by P.agglomerans on Ziziphus jujuba Mill.cv.Dongzao in Guangdong province,China.