Genetic diversity of Beauveria bassiana in different silkworm populations from Guangdong and Guangxi, southern China, based on SSRs.

The genetic diversity of 13 Beauveria bassiana strains in different silkworm (Bombyx mori) populations from Guangdong and Guangxi, southern China, was analyzed based on simple sequence repeats (SSRs). A total of 137 fragments were obtained with 9 SSR primers, on average 15 fragments each primer. Further analysis with POPGEN indicated that the inner-population genetic differentiation (Gst) was 0.0590, the polymorphic rate(PPL) was 97.73%, the Nei’s genetic diversity index (H) was 0.1896, and the Shannon’s information diversity index (I) was 0.3165. The level of genetic variation of Guangdong populations was higher (PPL=68.18%, H=0.1910, I=0.3044), while that of the Guangxi populations (PPL=65.91%, H=0.1713, I=0.1791) is smaller. The result showed that the genetic diversity of B. bassiana Guangdong strains was higher than that of B. bassiana Guangxi strains. The dendrogram of B. bassiana Guangdong and Guangxi strains was constructed by UPGMA cluster analysis based on the Nei’s genetic distance, and it is found that different strains from different collecting localities are divided into two clades. The results indicate that the genetic structure of B. bassiana from Guangdong and Guangxi is very complicated, and there is certain degree of similarity between the strains of Beauveria from the partial silkworm region, suggesting that it is feasible to trace the origin of B. bassiana with SSRs.