穿龙薯蓣、黄山药和盾叶薯蓣psbA-trnH片段序列分析

为研究薯蓣叶绿体psbA-trnH片段遗传多样性,探讨该片段用于中药穿龙薯蓣、黄山药和盾叶薯蓣种间分子鉴别和系统学研究中的意义,我们对不同类群薯蓣种的叶绿体psbA-trnH基因间区进行PCR扩增并测序,获得了该区间的完整序列,所得序列用软件MEGA3.0进行相关分析.穿龙薯蓣的psbA-trnH片段全长274bp,黄山药全长279bp,盾叶薯蓣植物个体内的叶绿体DNA则有两种psbA-trnH片段,长度分别为241bp和503bp.经MEGA3.0软件分析,3种薯蓣种间psbA-trnH片段序列的遗传距离(p-distance)为0.00350~0.04545,各个薯蓣种内的不同类群该序列无差异.用UPGMA法根据psbA-trnH序列的遗传距离建立系统发生树,聚类结果和形态分类相符.所得结果显示,psbA-trnH片段序列在所研究的3种薯蓣种内保守,在种间具有明显的较大差异,而3种薯蓣及薯蓣属的系统发生关系尚须进一步研究.图3表2参6

psbA-trnH Fragment Sequence Analysis of Dioscorea nipponica, D.panthaica and D. zingiberensis

To study the genetic diversity of psbA-trnH of Dioscorea and the value of the fragments used in molecular identity and systematics of three Dioscorea species (D. nipponica, D. panthaica and D. zingiberensis), the psbA-trnH fragments of the three species were amplified and sequenced,and were analyzed by software MEGA3.0. The length of D. nipponica and D. panthaica fragments was 274 bp and 279 bp, respectively; two psbA-trnH fragments existed in D. zingiberensis, and they were 241 bp and 503 bp long. The interspecific genetic distance (p-distance) of the three species was 0.003 50~0.045 45, and no intraspecific diversity existed. According to the genetic distance, phylogenetic tree was built by UPGMA method and the result showed by the phylogenetic tree was the same as morphological classification. Results indicated that the psbA-trnH fragments were highly conservative at intraspecific level and obviously diversified at interspecific level. However, the phylogenesis of the three Dioscorea species need further study. Fig 3, Tab 2, Ref 6