【摘要】 以我国北方不同地理来源的67株炭疽菌菌株为试材,采用ISSR分子标记聚类分析的方法,研究了苹果炭疽病病原菌的群体遗传多样性和群体遗传结构,以期为研究苹果炭疽病的流行和防治规律提供参考依据。结果表明:10条引物共扩增出65个位点的多态性条带,多态率100.00%。物种水平的聚类分析结果显示,在遗传相似系数0.76水平时,代表性炭疽菌菌株可区分为7个亚群,Nei′s基因多样性指数(H)均大于0.2水平,Shannon信息指数(Ⅰ)也均大于0.3水平,证明我国北方苹果炭疽病病原菌具有丰富的遗传多样性。通过对3个地理种群的遗传结构分析发现,遗传分化系数(Gst)显示渤海湾区最高,说明渤海湾区的遗传多样性最为丰富,内部的遗传分化较大,但每代迁移数Nm<1,说明种群内的基因交流受到抑制;而后2个地区黄河故道区和西北高原区的Gst值均较小,但种群的每代迁移数Nm较大,说明这2个种群遗传分化较小,种群遗传变异主要来自于群落内,种群内都存在丰富的基因交流。综合3个地理种群每代迁移数Nm=0.72,说明3个地区之间存在一定的菌源交流。更多还原

【Abstract】 To discuss the genetic diversity of pathogens associated with apple bitter rot at the molecular level,ISSR markers were applied to analyze the genetic diversity of 67 strains of Colletotrichumspp.causing bitter rot of apple in order to supply references for studying the epidemiology and control of apple bitter rot.The results showed that a total of 65 polymorphic bands were amplified with 10 screened primers,and the polymorphic loci percentage was 100.00%.Clustering analysis based on ISSR markers revealed that tested strains were clustered into seven groups at 0.76 genetic similarity coefficient by UPGMA.The results of genetic diversity of 67 strains from different geographical groups showed that Nei′s gene diversity index(H)and Shannon′s information index(I)were respectively greater than 0.2 and 0.3,which indicated that the genetic diversity all over China was considerably abundant.The results of population genetic structure of three geographical groups showed that Gst of the population from Bohai gulf area was the highest,indicating that the genetic diversity of this population was the most abundant and genetic differentiation among groups was bigger.The number of migrants per generation(Nm)of this group was less than 1,indicating that gene flow among groups was restrained.The Gst of the other population were lower but Nm were higher,indicating that genetic differentiation were lower and genetic variations existed within groups.There was significant gene flow within groups of old course of Yellow River and Northwestern Loess Plateau.The total Nm was 0.72,indicating that there was pathogen exchange among three geographical groups.更多还原