广西百色烟区烟草青枯病菌的遗传多样性分析

【目的】分析广西百色烟区烟草青枯病菌的遗传多样性,为了解该烟区青枯病的发生流行规律和该病原菌的致病机制提供参考。【方法】通过致病力测定、生化型鉴定及BOX-PCR对69株来源于广西烟草主产区百色烟区的青枯菌株的遗传多样性进行系统分析。【结果】供试菌株存在明显的致病力分化,强致病力菌株、中等致病力菌株和弱致病力菌株出现频率分别为17.39%、62.32%和20.29%,其中以中等致病力菌群为优势菌群;供试菌株的生化型复杂,其中37株属于生化型Ⅲ或生化亚型Ⅲ-1、Ⅲ-3和Ⅲ-4,23株属于生化型Ⅰ,1株属于生化型Ⅱ,另有8株属于非标准生化型;BOX-PCR分析结果表明百色烟草青枯病菌存在丰富的遗传多样性,聚类分析结果显示菌株的遗传多态性与菌株的地理来源、致病力、生化型具有一定的相关性,但并无明显的地理种群、生化型种群或致病力一致的种群聚在一起。【结论】广西百色烟区烟草青枯病菌具有丰富的遗传多样性和复杂的生化型,可能是该烟区烟草青枯病为害逐年加重的重要原因之一。

Genetic diversity of Ralstonia solanacearum isolated from tobacco in Baise,Guangxi

Objective]Genetic diversity analysis for Ralstonia solanacearum isolated from tobacco in Baise, Guangxi was studied in order to explore occurrence and epidemic regulation in Baise tobacco planting region and pathogenic mecha-nism of R. solanacearum. Method]Sixty-nine representative strains of R. solanacearum isolated from different places in Baise tobacco planting area of Guangxi were analyzed for genetic diversity by pathogenicity and biovar determination , and Box-PCR analysis. Result]All the tested strains presented obvious pathogenicity differentiation. The proportions belong-ing to high , moderate and low pathogenicity were 17.39%, 62.32% and 20.29% respectively. Strains with moderate pathogenicity were dominant ones. Base on biovar test, the biovar of the tested strains were complex. Thirty-seven strains belonged to biotypeⅢor subtype biochemicalⅢ-1,Ⅲ-3 andⅢ-4;twenty-three were biotypeⅠ;one belonged to bio-type Ⅱ and eight belong to atypical biovar. BOX-PCR analysis indicated that there was rich genomic diversity among all the tested R. solanacearum strains. According to clustering analysis, genetic diversity was related to geographical origin, pathogenicity and biovar to some extents. But there were no strain clusters with the same geographical origin , pathogenicity and biovar. Conclusion]R. solanacearum isolated from Baise, Guangxi has rich genetic diversity and complex biovar, and it may be one of the reasons why bacterial wilt causes more severe damages year by year in Baise tobacco planting area.