Genetic diversity and genetic structures of original plants of Viticis Fructus:an SSR markers-based analysis

Abstract

The present study aimed to provide the protection strategies for wild germplasm resources of original plants of Viticis Fructus and a theoretical basis for the sustainable use of Viticis Fructus. The genetic diversity and genetic structures of the 232 indivi-duals in 19 populations of Vitex rotundifolia and V. trifolia were analyzed by eight SSR markers with tools such as Popgene32, GenAlex 6.502, and STRUCTURE. Bottleneck effect was detected for the population with more than 10 individuals. The results indicated that 42 and 26 alleles were detected from the populations of V. rotundifolia and V. trifolia, respectively, with average expected heterozygo-sities of 0.448 6 and 0.583 9, which are indicative of low genetic diversity. AMOVA revealed the obvious genetic variation of V. rotundifolia and V. trifolia within population(84.43%, P<0.01; 60.37%, P<0.01). Furthermore, in eight SSR loci, six from V. rotundifolia populations and two from V. trifolia populations failed to meet Hardy-Weinberg equilibrium expectations(P<0.05), which confirmed that the populations experienced bottleneck effect. As assessed by Mantel test, geographical distance posed slight impacts on the genetic variation between the populations of V. rotundifolia and V. trifolia. Principal component analysis(PCA) and STRUCTURE analysis demonstrated evident introgression of genes among various populations. The original plants of Viticis Fructus were confirmed low in genetic diversity and genetic differentiation level. Therefore, the protection of wild resources of original plants of Viticis Fructus should be strengthened to ensure its sustainable use.