Genetic diversity and population structure of , a monotypic species.

Background: Understanding plant genetic diversity is important for effective conservation and utilization of genetic resources. (Thunb.) Dippel, is a monotypic species with high phenotypic diversity, narrow distribution, and small population size. In this study, we estimated the genetic diversity and population structure of using nine natural populations and inter-simple sequence repeat (ISSR) markers. Our results could provide a theoretical reference for future conservation and utilization of

Results: We obtained a total of 122 DNA bands, of which 121 (99.18%) were polymorphic. The average number of effective alleles ( = 1.4975), Nei's gene diversity index ( = 0.3016), and Shannon's information index ( = 0.4630) revealed that possessed a high level of genetic diversity. We observed that consisted of both deciduous and evergreen populations. UPGMA tree showed that the evergreen and deciduous form a sister group. There is little genetic differentiation among geographic populations based on STRUCTURE analysis. The Dice's similarity coefficient between the deciduous and evergreen populations was low, and the value was high, indicating that these two types of groups have high degree of differentiation.

Conclusion: Rich genetic diversity has been found in , deciduous and evergreen populations, and genetic variation mainly exists within the population. The low-frequency gene exchange between deciduous and evergreen populations may be the result of the differentiation of deciduous and evergreen populations. We suggest that in-situ protection, seed collection, and vegetative propagation could be the methods for maintenance and conservation of populations.