干旱区生态环境知识资源中心

Libanotis buchtormensis (Fisch.) DC. is a medicinal species exhibiting a disjunct distribution along the bilateral sides of deserts in northwestern China. The desert belt, as a phytogeography boundry, might play a key role in restricting gene flow of the species along the region. To determine the genetic pattern and evaluate the effect of the deserts barrier on the divergence of L. buchtormensis, inter-simple sequence repeat (ISSR) markers were used to investigate the genetic diversity and population structure of 19 populations separated by deserts in northwestern China. Ten selected primers generated 125 (90.58 %) polymorphic bands. Low level of genetic diversity (average h = 0.110) was detected at the population level, while higher diversity was detected at the species level (h = 0.298). Unrooted neighbor-joining distance-based phenogram, Bayesian clustering, and principle coordinate analysis revealed that the 19 populations well clustered into three distinct clades corresponding to their geographical origins. The analysis of molecular variance uncovered that a large component of the genetic differentiation was among populations (68.5 %). Genetic distances showed a significant correlation with geographic distances (r = 0.76, P < 0.001), demonstrating a strong geographical pattern of genetic differentiation. In general, the desert zone can be regarded as a geographical barrier to the disjunct distribution pattern of L. buchtormensis. This study provides basic genetic information of L. buchtormensis in China and sheds lights on the protection of some excessively damaged populations.