基于叶绿体rbcL和trnH-psbA序列的湖南茶树资源遗传多样性与亲缘关系研究

Genetic Diversity and Relationship Study of Hunan Tea Germplasm Resources Based on Chloroplast rbcL and trnH-psbA Sequence

DNA序列分析在物种进化、亲缘关系、遗传多样性研究中得到了广泛应用。采用筛选的叶绿体rbc L序列和trn H-psb A序列对湖南新收集的26份茶树种质资源进行亲缘关系和遗传多样性分析。结果表明:扩增的序列在去除边缘不准确的部分后,分别获得了582 bp(rbc L)和426 bp(trn H-psb A)的片段序列,rbc L序列的变异位点共27个,占扩增位点数的5.15%,trn H-psb A序列的变异位点共134个,占扩增总位点数的31.46%。rbc L序列在26个参试材料中共产生17个单倍型,Hd和π分别为0.961和0.008 32,trn H-psb A序列共产生26个单倍型,Hd和π分别为0.998和0.046 79,收集的茶树资源具有较高的遗传多样性。采用MEGA 6.0软件按照UPGMA法分别对rbc L序列和trn H-psb A序列构建了分子系统树,各序列对参试材料的聚类结果有一定差异,rbc L序列和trn H-psb A序列在自展数值大于50%情况下分别将参试材料分为了3个类群和4个类群。参试资源除部分江华苦茶由于亲缘关系较近而聚在一起外,大部分资源都单独形成1个分支,彼此间亲缘关系较远。

DNA sequence analysis was a more convenient method to study plant phylogenetic, genetic diversity and genetic relationship. Chloroplast trn H-psb A and rbc L sequence were used to evaluate the genetic diversity and relationship of 26 tea germplasm resources collected from Hunan. As a result, 582 bp（rbc L） and 426 bp（trn Hpsb A） fragment sequence were obtained, in which the variation sites of rbc L were 27, accounting for 5.15% of the amplified loci, and trn H-psb A had 134 variation sites, accounting for 31.46%. 17 rbc L haplotypes and 26 trn Hpsb A haplotypes were identified among 26 Hunan tea accessions. Values of Haplotype diversity（ Hd） and nucleotide diversity（ π） of 26 accessions identified by rbc L and trn H-psb A was 0.961, 0.008 32 and 0.998,0.046 79, respectively. The genetic diversity of all accession were very high. According to the UPGMA method on rbc L and trn H-psb A sequences, molecular phylogenetic trees were constructed using MEGA 6.0 software, the cluster results were not consistent each other, rbc L and trn H-psb A divied all accessions into 3 and 4 groups in bootstrap value is greater than 50%. Except part of Jianghua bitter tea plant germplasms, most of the resources had formed a separate branch, relationship among the 26 accessions was far. In this study, the genetic diversity and relationship of the 26 germplasm resources were revealed, which would provide an useful reference for the collection and conservation of Hunan tea germplasm resources.