基于rDNAITS序列探讨我国冬虫夏草的遗传分化及分布格局

Genetic differentiation and distributing pattern of Cordyceps sinensis in China revealed by rDNA ITS sequences

目的探讨我国冬虫夏草的遗传分化及分布格局。方法分析冬虫夏草rDNAITS序列差异及构建分子系统树。结果冬虫夏草ITS1-5.8S-ITS2序列在我国主要冬虫夏草产地21个居群间的差异较小,遗传距离仅为0～0.018。ITS1和ITS2序列中的GC的量与冬虫夏草居群的纬度呈极显著正相关,与居群的经度和海拔相关不显著。基于ITS序列的碱基变异将我国主要产地冬虫夏草分成4支,其地理位置与纬度有关,分别是环青海湖地区、青海中南部-甘肃-四川-西藏东北部区域、云南、西藏林芝米林地区。结论基于rDNAITS序列微小差异更能反映我国冬虫夏草资源在大尺度地理范围的分布格局,进一步证实了冬虫夏草的遗传分化主要发生于不同纬度间。

Objective To investigate the genetic differentiation and distributing pattern of Cordyceps sinensis in China. Methods Molecular phylogenetic tree was constructed by neighbour-joining analysis for the difference of ribosomal DNA internal transcribed spacers （rDNA ITS） of C. sinensis. Results Little difference in the ITS1-5.8S-ITS2 sequences were detected among the 21 populations of C. sinensis collected from the main producing areas in China. Their genetic distances just ranged from 0 to 0. 018. The GC contents of ITS1 and ITS2 sequences showed extremely significant positive correlation with the latitudes of each C. sinensis popUlations, and no significant correlation with the longitudes and altitudes. Based on the ITS sequences, the C. sinensis from the main producing areas in China should be divided into four groups, which seems to match with the geographic distribution along latitudinal gradient, i.e. area around Qinghai Lake, area including Mid-southern of Qinghai-Gansu-Sichuan-Northeastern of Tibet, Yunnan, and Linzhi and Milin of Tibet, respectively. Conclusion The tiny difference of rDNA ITS sequences are more suitable for revealing the distributing pattern of C. sinensis resources with large geographic ranges in China. The results farther confirm that the genetic differentiation of C. sinensis exists among different latitudes.