The Population Genetic Structure And Gene Flow Of Kmeria Septentrionalis Assessed By Microsatellite Markers

Kmeria septentrionalis Dandy belongs to the Magnoliaceae family. It is an endemic species to China and is listed as endangered species in the China Species Red List. K. septentrionalis. is narrowly distributed in northern Guangxi (Luocheng and Huangjiang), southeast Guizhou (Libo), and southeast Yunnan (Malipo and Maguan). K. septentrionalis is a dioecious tree.In this study, the genetic diversity and population genetic structure of K. septentrionalis were analyzed by using microsatellite molecular markers. Gene flow and effective dispersal distance of pollen was studied by paternity analysis.The main results are as follows:Fourteen microsatellite primers were successfully developed by magnetic beads enrichment method. The fourteen effective microsatellite sequence in the GenBank accession number is HQ888826-HQ888839. The allele number ranged from3to15per loci, the observed and expected heterozygosity ranged from0.2692to0.9667and0.3271to0.8881respectively. It suggested that these locus have high polymorphism. These microsatellite markers will be useful in further studies on its genetic diversity and gene flow.The329open-pollinated offsprings come from7maternal trees were analyzed. The number of alleles per locus was from4to15, and the total polymorphic alleles in7loci was63. Useing CERVUS software to analysis, it could assign the real paternity for its132offsprings (40.1%of the total offsprings) beyond the80%confidence. The pollen of72(54.5%) from the assigned offsprings are from the male paren trees that less than20m away from the female paren. The distance of pollen movement ranged from2.2m to535.4m.A total of592individuals of K. septentrionalis were collected from14populations. Its genetic diversity and genetic structure were analyzed by using7pairs of mierosatellite primers. The results showed that K. septentrionalis maintain a high level of genetic diversity, and a low gene differentiation among populations. In14populations, the mean number of alleles ranged from5.143to8.571, expected heterozygosity ranged from0.568to0.752, and observed heterozygosity ranged from0.522to0.805. The genetic differentiation index among populations ranged from0.022to0.176, genetic differentiation among populations are low. The gene flow of between the populations are very frequent. The results of bottleneck effect test indicated that all populations have not experienced a bottleneck effect, except one population.In summary, this study revealed that K. septentrionalis have high level of the genetic diversity, low genetic differentiation among populations, and high gene flow among populations. These results provide a scientific foundation for protecting K. septentrionalis.