Genetic diversity and differentiation of the endangered and endemic species Sauvagesia rhodoleuca in China as detected by ISSR analysis.

Sauvagesia rhodoleuca (Ochnaceae) is an endangered plant that is endemic to southern China. The levels of genetic variation and patterns of population structure in S. rhodoleuca were investigated using inter-simple sequence repeat markers. Eleven primers were used to amplify DNA samples from 117 individuals, and a total of 92 loci were detected. Our results indicated that genetic diversity was quite low both at the species level (percentage of polymorphic bands (PPB) = 41.30%, Nei's gene diversity (h) = 0.1331, and Shannon information index (I) = 0.2028) and the population level (PPB = 16.30-28.26%, h = 0.0496-0.1012, and I = 0.0756-0.1508). A high level of genetic differentiation among populations was detected based on Nei's genetic diversity analysis (0.4344) and analysis of molecular variance (47.03%). The low genetic diversity within population and high population differentiation of S. rhodoleuca were assumed to result largely from limited gene flow, genetic drift, inbreeding, and clonal growth. Conservation strategies for this endangered species are proposed based on the genetic data.