云南省烟草镰刀菌根腐病菌遗传多样性分析

【背景和目的】尖孢镰刀菌（Fusarium oxysporum）引起的根腐病是烟草主要的土传病害，在云南烟区普遍发生。为分析云南省不同地理来源尖孢镰刀菌的遗传差异性和亲缘关系。【方法】采用ISSR(inter-simple sequence repeat)和SRAP(sequencerelated amplified polymorphism)分子标记技术分析40株菌株遗传多样性。【结果】（1）采用ISSR技术，供试的7条引物共扩增出53条条带，其中多态性条带44条，平均多态性条带83.02%。菌株间的遗传相似系数为0.49～0.96，存在遗传背景差异。遗传相似系数为0.68时，40株菌株可分为3个类群。（2）采用SRAP技术，供试的7对引物共扩增出44条条带，其中多态性条带32条，平均多态性条带72.73%，菌株间的遗传相似系数为0.55～0.96。遗传相似系数为0.70时，40株菌株可分为3个类群，结果与ISSR一致。【结论】云南省烟草尖孢镰刀菌菌株间遗传差异大，ISSR和SRAP分子标记技术可用于烟草尖孢镰刀菌的遗传多样性分析。

Genetic diversity of Fusarium oxysporum isolates causing Tobacco Root Rot in Yunnan

  Objective  Root rot caused by Fusarium oxysporum is the main soil-borne disease of tobacco, which occurs in most of the tobacco growing areas in Yunnan province. Fusarium oxysporum is the major pathogen causing tobacco root rot. In order to understand the genetic difference and phylogenic relationship among the Fusarium oxysporum isolates collected from the different major tobacco growing areas in Yunnan, the genetic diversity of 40 Fusarium oxysporum isolates separated from diseased plants was examined.  Methods  The genetic diversity of forty Fusarium root rot pathogen isolates collected from different tobacco growing areas in Yunnan province were studied using inter-simple sequence repeats (ISSR) and sequence related amplified polymorphism (SRAP) molecular marker technology.  Results  (1) A total of 53 loci were obtained using 7 ISSR primers and 44 loci were polymorphic, and the average polymorphism ratio was 83.02%. UPGMA cluster analysis and genetic similarity coefficient showed that 40 Fusarium oxysporum isolates could be grouped into three distinct families based on similarity coefficient of 0.68. The similarity coefficient of the 40 isolates ranged from 0.49 to 0.96, indicating differences in the genetic background. (2) Using SRAP molecular markers technology, 44 bands were amplified by 7 pairs of primers, including 32 loci polymorphic bands, the average polymorphism ratio was 72.73%, and the similarity coefficient ranged from 0.55 to 0.96. In the UPGMA cluster analysis, the result of SRAP was consistence with ISSR, 40 isolates could be categorized into three distinct families based on the similarity of 0.7.  Conclusion  ISSR and SRAP markers were both available in the genetic diversity analysis of Fusarium oxysporum, and the tested isolates showed high degree of genetic differentiation.