摘要
分析来自湖南省道县(DX)、张家界市(ZJJ)、芷江县(ZJ)、麻阳县(MY)和贵州省玉屏县(YP)以及泰国(TL)6个橙黄乳菇种群38个菌株的ITS-5.8S序列的遗传结构和遗传多样性。所有的ITS-5.8SrDNA序列样品共检测到2个变异位点,碱基A、T、G、C的平均含量分别为22.5%、26.9%、22.7%和27.9%。根据序列的核苷酸变异共定义了3种单倍型,其中单倍型Hapolotype 3是湖南和贵州5个种群共享单倍型,Hapolotype 2为6个种群的共享单倍型。中国橙黄乳菇各地区种群的单倍型多样性(haplotype diversity,HD)在0.21875～0.59375之间,表明橙黄乳菇种群具有较高的单倍型多样性。遗传分化指数(fixation index,FST)表明,不同地理种群间的遗传分化较大。AMOVA分析显示,种群间的遗传变异占总变异的17%,种群内部变异占总变异的83%。Mantel测试显示地理距离与种群的遗传分化FST值之间线性关系显著(P<0.05)。采用N-J法构建的分子系统树表明,当与乳菇属相近种进行比较时,湖南、贵州和泰国不同地区的所有橙黄乳菇样品紧密聚为一支。采用中性检验进行分析,推测湖南橙黄乳菇群体样品在进化上遵循中性模型,并且经历过种群扩张过程。研究结果表明橙黄乳菇种群具有丰富的遗传多样性。
Lactarius akahatsu is an edible ectomycorrhizal fungus of high economic value, which plays an important role in the growth of pine trees. Although understanding the population structure, genetic diversity, genetic structure, and evolution of L. akahatsu is essential to protect this valuable fungus, only a few studies have so far focused on the genetic background, geographical differentiation, and collective evolution of L. akahatsu, In this study, ITS-5.8S rDNA sequencing was used to analyze the genetic structure and genetic diversity of six L. akahatsu populations comprising 38 strains isolated from sites in Daoxian, Zhangjiajie, Zhijiang, Mayang and Yuping in China and in Thailand. Two variable regions were detected in all the 1TS-5.8S rDNA sequences. The average contents of A, T, G and C were 22.5%, 26.9%, 22.7% and 27.9% respectively, and the average ratio of transition and transversion （Ts/Tv） of the sequences was 9.56. Three haplotypes were defined based on nucleotide variation： hapolotype 3 was shared by five L. akahatsu populations from Hunan, whereas hapolotype 2 was shared by six L. akahatsu populations from Hunan, Guizhou and Thailand. Haplotype diversity values for L. akahatsu populations in China ranged between 0.21875~0. 59375, indicating a high degree of genetic diversity. The genetic differentiation index, FST, revealed that the genetic differentiation among L. akahatsu populations obtained from different geographical locations was relatively significant. The percentage of genetic variation among L. akahatsu populations compared with the total variation was 17%, whereas the ratio within L. akahatsu populations compared with the total variation was 83%. The Mantel test indicated that a significant linear relationship （P〈0. 05） existed between the geographical distance and FST values of the L. akahatsu populations. L. akahatsu samples obtained from all the different regions formed a single cluster in a molecular phylogenetic tree when the coenospecies of L. akahatsu were compa
出处
《食用菌学报》
北大核心
2012年第3期29-36,共8页
Acta Edulis Fungi
基金
国家自然科学基金(编号:30972371)的部分研究内容
