香蕉细菌性软腐病菌致病性分化和遗传多样性分析

On Pathogenicity Variation and Genetic Diversity of Dickeya Paradisiaca Isolates Causing Banana Bacterial Soft Rot

目的:研究广东香蕉细菌性软腐病菌Dickeyaparadisiaca的致病性差异和遗传多样性.方法:采用香蕉假茎离体接种法和幼苗盆栽接种法对分离自广东香蕉的13个菌株进行致病性分析;利用16S-23SrDNA转录间隔区PCR(ITS-PCR)和细菌基因组的重复序列PCR(Rep-PCR)技术,对供试菌株的遗传多样性进行研究.结果:采用2种不同的接种方法,供试菌株致病力均可划分为强(++++)、较强(+++)和中等(++)3种致病型,2种方法得到的结果基本一致,且与菌株的地理来源有一定的相关性;利用ITS-PCR扩增,可将供试菌株划分为6个组群;而利用细菌基因组重复序列通用引物BOX和J3进行Rep-PCR扩增,在遗传距离为0.52时,供试菌株可被划分为2个遗传相似组,其中组1为主要组群;在遗传距离为0.65时,供试菌株可被划分为4个遗传相似组,其中组3和组4为主要组群.结论:侵染广东香蕉的细菌性软腐病菌存在明显的致病性分化和丰富的遗传多样性.

To determine the pathogenicity variation and genetic diversity of banana bacterial soft rot bacte-ria in Guangdong province,the analysis of pathogenicity variation of 1 3 isolates of Dickeya paradisiaca was completed on the basis of the methods of pseudostem inoculation in vitro and seeding pot inoculation. ITS-PCR and Rep-PCR have been used to analyze the genetic diversity.The results of pathogenic classifi-cation is consistent by both of inoculation methods,and all the tested isolates could be divided into three types,severe(++++),strong(+++)and medium(++).It seems that there was a high degree of correlation between the pathogenicity and geography.All the isolates could be clustered into six groups by using ITS-PCR.Using the degenerate primer pair of Box and J3 of bacterial repetitive sequences,the Rep-PCR was completed.Two groups have been generated with the genetic distance of 0.52,and the first group was dominating.While all the tested isolates were divided into four genetic groups when the genetic distance was 0.6 5 ,in which the third and fourth group were dominating.The results indicated that signifi-cant pathogenicity variation and genetic diversity exist within the populations of banana bacter soft rot iso-lated in Guangdong.