Genetic patterns investigation of wild Chimonanthus grammatus M.C.Liu by using SSR markers

Chimonanthus grammatus M.C.Liu is an endangered and national-protected medicinal plant species with highly restricted and disjunctive geographical distribution in the border area of Anyuan and Huichang counties of Jiangxi province, China. In this study, six natural populations of the C. grammatus (AY1, AY2, and AY3 from Anyuan; HC1, HC2, and HC3 from Huichang county) and one cultivated population of Chimonanthus praecox (as one outgroup) from Nanchang (NC) city, Jiangxi, were sampled to analyze its genetic diversity and structure using ten microsatellite (SSR) markers. Results showed that Nei's genetic diversity values (He) of seven populations ranged from 0.574 to 0.742, with an average of 0.666 ± 0.028. Values of Shannon's information index (I) per population ranged from 1.215 to 1.832, with an average of 1.535 ± 0.074. For C. grammatus species, AY1 population from Anyuan county harbored the highest genetic diversity (I = 1.832 ± 0.195, He = 0.742 ± 0.061), while HC3 population from Huichang county had the lowest levels of genetic diversity (I = 1.358 ± 0.208, He = 0.601 ± 0.078), respectively. The low genetic differentiation (Fst = 0.089) was detected in C. grammatus species. UPGMA and PCA analyses classified the seven populations into three branches: AY1, AY2 and AY3 were clustered together; HC1, HC2, and HC3 were grouped together; and NC was clustered by itself. These results revealed that ten SSR markers were effective to investigate the genetic diversity of C. grammatus and to genetically differentiate it from another species in Chimonanthus.