Genetic diversity and population structure of Camellia huana(Theaceae),a limestone species with narrow geographic range,based on chloroplast DNA sequence and microsatellite markers

Camellia huana is an endangered species with a narrow distribution in limestone hills of northern Guangxi and southern Guizhou provinces,China.We used one chloroplast DNA(cpDNA)fragment and 12 pairs of microsatellite(simple sequence repeat;SSR)markers to assess the genetic diversity and structure of 12 C.huana populations.A total of 99 alleles were detected for 12 polymorphic loci,and eight haplotypes and nine polymorphic sites were detected within 5200 bp of cpDNA.C.huana populations showed a low level of genetic diversity(n=8,Hd=0.759,Pi=0.00042 for cpDNA,NA=3.931,HE=0.466 for SSRs),but high genetic differentiation between populations(FST=0.2159 for SSRs,FST=0.9318 for cpDNA).This can be attributed to the narrow distribution and limestone habitat of C.huana.STRUCTURE analysis divided natural C.huana populations into two groups,consistent with their geographical distribution.Thus,we suggest that five natural C.huana populations should be split into two units to be managed effectively.