我国小麦落选短体线虫群体遗传多样性分析

Genetic diversity of Pratylenchus neglectus populations on wheat in China

为了明确我国落选短体线虫群体的遗传多样性,利用mtCOI基因标记对落选短体线虫9个地理群体的遗传结构及遗传分化进行分析。结果显示,9个地理群体中共得到101条mtCOI序列,发现28个碱基变异位点,形成14个单倍型。其中,H1单倍型最常见,为7个地理群体的59个个体共有,推测其可能为祖先单倍型。全部地理群体在物种水平呈现中等遗传多样性(HT=0.706±0.131),聚类分析显示其可分为类群Ⅰ与类群Ⅱ两个类群,AMOVA分析揭示落选短体线虫整体水平的遗传分化主要来源于种群间。Mantel检验表明落选短体线虫群体的遗传距离与地理距离存在正相关性,但是不同种群之间的遗传分化程度与地理距离没有显著关系。中性检验和错配分布检验均揭示落选短体线虫在整体水平和两个类群上的群体历史动态都处于相对稳定的状态。

In order to clarify the genetic diversity of Pratylenchus neglectus populations in China,the genetic structure and genetic differentiation of 9 geographical populations were analyzed using the mtCOI gene as the marker.The results showed that a total of 101 mtCOI sequences were obtained from 9 populations,28 variable nucleotide sites were discovered,and 14 haplotypes were formed.The haplotype H1 was the most common one shared by 59 individuals from 7 populations,which was speculated might be the ancestral haplotype.All the geographical populations showed the moderate genetic diversity at the species level(HT=0.706±0.131),and the cluster analysis showed that they could be divided into two groups,as the GroupⅠand GroupⅡ.The AMOVA analysis revealed that the genetic differentiation at the whole level of P.neglectus populations was mainly derived from the inter-populations.The Mantel test showed that the genetic distance among P.neglectus populations was positively correlated with their geographical distance,although there was no significant correlation between the genetic differentiation and the geographical distance among different populations.Both the neutrality test and the mismatch distribution test revealed that the historical dynamics of P.neglectus populations at the whole level as well as at the two-groups level were relatively stable.