Analysis of genetic diversity among five closely related species used as ‘Xihuangcao’ herbs using ISSR and SCoT molecular markers

Abstract

Many plants of the genus Isodon (Benth.) Kudo from Lamiaceae, such as Isodon serra (IS), Isodon lophanthoides (IL), etc., are widely used as the source of traditional Chinese herbal medicine “Xihuangcao” in Lingnan region of China. The origin of “Xihuangcao” herb is relatively chaotic and germplasm resources are unclear. In the present research, evaluation of genetic diversity and genetic variability in 358 accessions of ‘Xihuangcao’ herb from 33 populations were carried out based on ISSR and SCoT makers. Thirteen ISSR and 8 SCoT markers produced 491 and 272 fragments respectively, of which 99.80% (490) and 99.26% (270) were polymorphic, H=0.1719 I=0.1704 for ISSR and H=0.2057 I=0.3300 for SCoT revealed high genetic diversity. Both genetic differentiation analysis and AMOVA revealed higher variance among the populations than within populations. According to UPGMA and PCoA, the clustering patterns of populations were out of accordance with plant taxonomy or geographic distribution. This study showed that the germplasm resources of “Xihuangcao” had high genetic diversity, which could provide materials for excellent breed screening and core collections developing.