中国不同地区绞股蓝ITS序列分析

ITS Sequence analysis of Gynostemma pentaphyllum from different habitats in China

目的比较中国不同地区绞股蓝的nrDNAITS碱基序列的差异,以期分析绞股蓝的地理分布与ITS基因型的相关性,为我国不同地区绞股蓝的鉴别提供分子依据。方法PCR克隆测序,MegAlign(DNASTAR)软件对序列进行对位排列,PAUP4.0b10软件进行系统发育分析,构建最大简约树。结果绞股蓝ITS区长度为658～659bp,变异位点为8.48%,信息位点为2.72%。不同地区的样品在碱基的量、信息位点的碱基位置和遗传距离等方面存在一些差异。系统发育分析表明ITS基因型与绞股蓝的地理分布具有一定的相关性,但也有部分不一致,可能主要是因为绞股蓝种内复杂的倍性。结论ITS序列可作为中国不同地区绞股蓝的一种良好的分子标记,而要确定不同地区的绞股蓝合理的亲缘关系还需要结合其他方面的证据。

Objective By comparing the difference for ITS sequences of Gynostemma pentaphyllum from different habitats in China, to investigate the correlation between ITS genotype and geographic loca- tion and provide molecular evidence for identification of G. pentaphyllum from different habitats in China. Methods PCR Clone sequencing, sequence alignments were performed using MegAlign （DNASTAR）, phylogenetic analyses were conducted using PAUP4.0b10 by maximum parsimony （MP） criteria. Results The length of ITS region varied from 658 to 659 bp. The proportion of variablesites is 8.48% and the pro- portion of parsimony information （parsim-info） sites is 2. 72%. Some differences in the base contents, po- sition of parsim-info sites, and genetic distance were detected from samples collected from different habi- tats. Phylogenetic analysis showed some correlation between ITS genotype and geographic location of G. pentaphyllum; but there were also some discrepancies between geographical location and affinity, which may mainly caused by the complex cytotypes in G. pentaphyllurn. ConClusion The nrDNA ITS could be a good marker to distinguish G. pentaphyllurn from different habitats in China, but the rational affinity could be determined through associating these ITS data with other evidence.