西瓜枯萎病菌遗传多样性的相关序列扩增多态性分析

Genetic diversity analysis of Fusarium oxysporum f.sp. niveum by sequence-related amplified polymorphism

对30个西瓜枯萎病菌Fusarium oxysporum f.sp.niveum菌株基因组DNA进行相关序列扩增多态性(SRAP)分子标记分析,以探究其遗传多样性与地理来源的关系。采用尖孢镰刀菌西瓜专化型Fusarium oxysporumf.sp.niveum0、1、2号生理小种的基因组DNA为模板,对225对SRAP引物进行筛选,筛选出20对多态性、重复性较好且条带清晰的引物,对30个菌株进行PCR扩增,共扩增出386条带,其中多态性条带有371条,多态性比率为96.11%,平均每对引物扩增出19.3个位点和18.55个多态性位点。UPGMA法聚类分析结果显示,供试菌株两两之间的遗传相似系数范围为0.69~0.90,平均为0.79,说明尖孢镰刀菌西瓜专化型的遗传多样性较为丰富。基于SRAP标记聚类分析表明,30个菌株在遗传相似系数为0.70处被划分为3个类群,I类群包含24个菌株,其中18个来自湖南省,Ⅱ类群只包含1个来自黑龙江省哈尔滨市的菌株,它和另一个来自黑龙江地区的菌株被划分到不同的类群,且遗传距离相对较远;Ⅲ类群包含了5个菌株,其中3个来自海南三亚,其余两个来自湖南省。根据菌株的分布情况来看,菌株的聚集与地理来源没有明显的相关性。

In order to explore the relationship between genetic diversity and geographical origin,genomic DNA of 30 strains of Fusarium oxysporum f.sp.niveum isolates were analyzed by sequence-related amplified polymorphism(SRAP)molecular markers.With genomic DNA of F.oxysporum f.sp.niveum race 0,race 1 and race 2 as templates,20 pairs of primers which had rich product and high polymorphism and repeatability were screened from total 225 pairs of SRAP primers.The 20 pairs of SRAP primers generated a total of 386 reproducible bands by PCR with the genomic DNA from 30 tested materials as templates.371 bands were polymorphic,with polymorphism ratio of 96.11%.On average,the bands amplified by each primer combination were 19.3 including 18.55 polymorphism bands.The UPGMA cluster analysis revealed that the genetic similarity coefficient of all the stains was ranged from 0.69 to 0.90,averaged 0.79,indicating the genetic diversity of F.oxysporum f.sp.niveum was abundant.Based on SRAP marker clustering analysis results,30 isolates were classified into 3 groups with genetic similarity of 0.70.Group I contains 24 isolates,with 18 isolates from Hunan Province.GroupⅡonly contains one strain from Harbin City,Heilongjiang Province.The two strains from Harbin City were divided into different groups and the genetic distance was relatively far.GroupⅢcontains 5 isolates,3 from Sanya,Hainan Province and two from Hunan Province.As far as the strains distribution was concerned,there was no significant correlation between the aggregation of the strains and the geographical origin.