赣南地区番茄青枯菌菌系多样性分析

【目的】分离鉴定赣南地区番茄青枯病菌,明确菌系分化,为当地番茄抗青枯病育种和病害防治奠定基础。【方法】从江西省赣南地区采集番茄青枯病病株,经选择性平板分离、纯化和分子鉴定,获得不同地理来源的青枯菌Ralstonia solanacearum菌株。通过生理生化测定和接种番茄试验,鉴定青枯菌的生化变种和致病类型。PCR扩增内切葡聚糖酶基因egl序列,明确青枯菌的演化型和序列变种。双层平板培养法测定其对8个不同噬菌体的敏感性。【结果】获得了来自赣南地区9个市(县)的番茄青枯菌菌株44个,其中,41个菌株为生化变种Ⅲ,3个菌株为生化变种Ⅳ;致病力测定结果聚为I、II和III类,其致病力分别为强、中和弱,其中,强致病力菌株占65.9%。所有菌株属于亚洲分支演化型(Ⅰ),并进一步划分为Sequevar13、14、15、17、18、34、44和48等8个序列变种。大部分菌株对供试的8个噬菌体敏感。【结论】赣南地区番茄青枯菌以生化变种III和强致病力菌株为主,对噬菌体较敏感,存在8个序列变种,具有明显的菌系分化现象和遗传多样性。

Diversity of Ralstonia solanacearum strains from tomato in the south of Jiangxi Province

Objective Isolating and identifying Ralstonia solanacearum strains from tomato plants in the Southern of Jiangxi Province, and clarifying the bacterial differentiation can lay the foundation for local tomato bacterial wilt resistance breeding and disease control.Method The diseased tomato plants were collected from the south of Jiangxi Province, R. solanacearum strains with different geographical origins were isolated by selective plate, purificated and identificated by PCR. The test of physiology and biochemistry and inoculation on tomato plants were conducted for the determination of biovar and virulence difference. The endoglucanase gene (egl) fragments were amplified by PCR to determine the phylotype and sequevar of R. solanacearum.Result A total of 44 R. solanacearum strains were obtained from nine cities (counties) in the south of Jiangxi Province, among which 41 strains were identified as biovar III and three strains were identified as biovar IV. According to the results of virulence difference, 44 strains were clustered into three groups, namely group I (high virulence), group II (moderate virulence) and group III (weak virulence), of which group I (high virulence) strains accounted for 65.9%. All strains were belonged to the phylotype I and further divided into eight sequevars, namely Sequevar 13, 14, 15, 17, 18, 34, 44 and 48 respeclively. Most R. solanacearum strains were sensitive to the eight tested bacteriophages.Conclusion The strains of R. solanacearum from tomato in the south of Jiangxi Province are mainly biovar III and high virulence, sensitive to bacteriophages, have eight sequevars, and have obvious differentiation and genetic diversity.