Evaluation of the Genetic Diversity of Bauhinia winitii, an Endemic Plant of Thailand, Using Microsatellite Markers

Bauhinia winitii Craib is an endemic species native to Thailand. Genetic diversity was assessed using microsatellite markers developed from a library enriched using (AG)20/(CAG)20 oligonucleotide probes. Eight polymorphic loci produced a total of 28 alleles with a mean number of 3.5 alleles per locus from 33 specimens of B. winitii. The averages of the expected (He) and observed (Ho) heterozygosity were 0.418 and 0.394, respectively. The average value of polymorphic information content (PIC) was 0.364, and two SSR loci were highly informative. Significant linkage disequilibrium (LD) was observed between one pair of loci and a significant deviation from Hardy-Weinberg equilibrium (HWE) (P < 0.05) was detected at three loci. The B. winitii population in Thailand has a moderate level of genetic diversity and a low level of inbreeding. The cross-species transferability success rate among Bauhinia species of the SSRs derived from B. winitii was 75% (B. acuminata), 100% (B. aureifolia), and 100% (B. strychnifolia). These newly developed SSR primers provide a useful genetic tool for analyzing the population structure of B. winitii and the genetic diversity of the related species – B. acuminata, B. aureifolia, and B. strychnifolia. Information from this study can be useful for developing conservation and protection plans as well as management of the genetic resources of B. winitii, an endemic plant in Thailand.