Genetic diversity and population structure of the endangered conifer Taxus wallichiana var. mairei (Taxaceae) revealed by Simple Sequence Repeat (SSR) markers

Taxus wallichiana var. mairei is an endangered conifer with important medicinal value in southern China. Nuclear SSR markers were employed to assess genetic diversity and structure of 13 geographically disjunct populations. The present study revealed a moderate genetic diversity (HE = 0.538) and low genetic differentiation (FST = 0.159). And most populations encountered in severe inbreeding and bottleneck effect. No significant genetic structure was detected by IBD and Structure analysis, which was supported by AMOVA analysis. The present results could be ascribed to an earlier period of more pronounced gene flow when the species had a more continuous distribution. However, the 13 studied populations were divided into four clusters based on the UPGMA dendrogram; these clusters were almost congruent with their geographical distributions. Vital areas such as southern mountains of Sichuan basin, Nanling Mts. and the margin of this yew's distribution range had a high priority for conservation.