大豆枯萎病菌尖孢镰孢遗传多样性及大豆品种抗性

Genetic diversity of Fusarium oxysporum and identification of resistance to soybean Fusarium wilt on soybean lines

了解大豆枯萎病菌的群体遗传特征及明确大豆种质对大豆枯萎病的抗性,对抗病育种、抗性品种的合理布局以及制定更有效的病害防治策略具有重要的参考价值。本研究利用随机扩增多态性DNA(random amplified polymorphic DNA,RAPD),对采自我国不同地区的大豆枯萎病菌—尖孢镰孢菌(Fusarium oxysporum)进行遗传多样性分析,筛选到10个多态性随机引物,共扩增出75条RAPD条带,其中55条为多态性条带,占73.3%。利用UPGMA法对DNA扩增图谱进行聚类分析,以相似系数0.68为阈值,55个分离物可分为9个遗传聚类组,表明我国大豆枯萎病菌具有丰富的种内遗传多样性,所划分的群体与分离物来源地不相关。同时,对上述分离物进行致病性分析,发现我国的大豆枯萎病菌具有明显的致病力分化现象。进一步利用3个代表性分离物对来自我国不同大豆产区的180个大豆品种(资源)进行抗大豆枯萎病鉴定,发现皖豆28、中黄13、中黄51、中作X08076和5D034等5个品种对大豆枯萎病具有良好抗性,占供试材料的2.8%,表明不同大豆品种对枯萎病的抗性存在一定的差异。

Soybean Fusarium wilt caused by Fusarium oxysporum is one of the most devastating soybean diseases worldwide. Understanding the population genetic characteristics of the pathogen and the resistance of soybean germplasm to soybean Fusarium wilt will benefit resistance breeding of soybean, reasonable distribution of resistant varieties and development of new disease management strategies. To clarify the genetic variation among F. oxysporum isolates, the genomic fingerprints of 55 isolates of F. oxysporum collected from different soybean-growing areas were analyzed by using 10 RAPD primers. The results showed that 75 bands were amplified and among them, 55 bands were polymorphic （73.3%）. By using UPGMA, the 55 isolates were clustered into 9 groups when the threshold value of the similarity coefficient is 0.68, indicating that F. oxysporum isolates are diverse.We found that F. oxysporum isolates displayed pathogenicity differentiation on soybean lines and soybean lines also showed resistance differentiation to different F. oxysporum isolates. To make clear the resistance of soybean germplasm to soybean Fusarium wilt, 180 soybean lines from soybean-producing areas and breeding units were screened. The results showed that 5 lines （Wandou28, Zhonghuangl3, Zhonghuang51, ZhongzuoX08076 and 5D034） were high resistant to soybean Fusarium wilt, accounting for 2.8% of the total materials. In addition, our findings revealed that the proportion of resistant germplasm in different soybean pro- ducing areas is different.