基于叶绿体psbK-psbI序列的石斛属药用植物鉴定

Identification of medicinal plant Dendrobium based on the chloroplast psbK-psbI intergenic spacer

本文对18种石斛属药用植物及其混伪品的叶绿体psbK-psbI序列进行PCR扩增和测序,比较分析其序列特征。石斛属药用植物叶绿体psbK-psbI基因间隔区长度为474~513 bp,GC含量25.4%~27.6%,变异位点71个,简约信息位点46个。石斛属种间K2P遗传距离为0.006 1~0.058 1,平均为0.028 4,与混伪品密花石豆兰之间K2P遗传距离为0.093 2~0.120 4。石斛属种间均能在NJ树中明显区分,6份待检样品均成功鉴定。叶绿体psbK-psbI序列可作为石斛属物种分子鉴定的候选标记。

In this paper, the chloroplast psbK-psbI intergenic spacers of 18 species of Dendrobium and their adulterants were amplified and sequenced, and then the sequence characteristics were analyzed. The sequence lengths of chloroplast psbK-psbI regions of Dendrobium ranged from 474 to 513 bp and the GC contents were 25.4%-27.6%. The variable sites were 71 while the informative sites were 46. The inter- specific genetic distances calculated by Kimura 2-parameter （K2P） of Dendrobium were 0.006 1-0.058 1, with an average of 0.028 4. The K2P genetic distances between Dendrobium species and Bulbophyllum odoratissimum were 0.093 2-0.120 4. The NJ tree showed that the Dendrobiurn species can be easily differentiated from each other and 6 samples of the inspected Dendrobium species were identified successfully through sequencing the psbK-psb! intergenic spacer. Therefore, the chloroplast psbK-psbI intergenic spacer can be used as a candidate marker to identify Dendrobium species and its adulterants.