Genetic Diversity of the Endemic Plant, Boesenbergia siamensis (Gagnep.) P. Sirirugsa and Cross Amplification among Zingiberaceae by Microsatellite Markers

Boesenbergia siamensis (Gagnep.) P. Sirirugsa or Krachaai Sayam is a rhizomatous perennial herb that belongs to Zingiberaceae family. It is an endemic plant that has a restricted distribution in Kanchanaburi Province, Thailand. In order to obtain base-line data for the conservation of this species, investigation of genetic diversity is necessary. This study, therefore aimed to survey and study genetic diversity of B. siamensis (Gagnep.) P. Sirirugsa using microsatellite markers. An enriched genomic library of this species was constructed from genomic DNA of B. siamensis (Gagnep.) P. Sirirugsa using (AG)₂₀ and (CAG)₂₀ as biotinylated oligo DNA probes. As a result, 20 polymorphic microsatellite markers were developed and tested in 25 individual samples of Boesenbergia siamensis (Gagnep.) P. Sirirugsa. The number of alleles varied from four to 15 with an average of 9.70 alleles per locus. The PIC value of all polymorphic SSRs ranged between 0.547 and 0.899. The average values of observed and expected heterozygosity were 0.604 and 0.819, respectively. Moreover, cross-amplification was investigated with three samples each of B. thorelii (Gagnep.) Loes., B. rotunda (L.) Mansf. (orange rhizomes) and Kaempferia parviflora Wall. Of 20 newly developed microsatellite primers, the results showed that they were able to amplify in at least two samples of each species/genera. Twelve (60%) primer pairs were amplified with B. thorelii (Gagnep.) Loes. and B. rotunda (L.) Mansf., while nine (45%) pairs were amplified with K. parvifloraWall.