RESUMO
Human-driven habitat fragmentation leads to spatial isolation of endangered plant species increasing extinction risk. Understanding genetic variability and population structure of rare and isolated plant species is of great importance for assessing extinction risk and setting up conservation plans. Aconitum austrokoreense, an endangered and endemic species in Korea, is a perennial herb commonly used for medicinal purposes. We used five nuclear microsatellites and one chloroplast marker to investigate genetic diversity and population structure for 479 individuals of A. austrokoreense from seven populations throughout South Korea. A multivariate approach, discriminant analysis of principal components analysis, revealed broad-scale spatial patterns of A. austrokoreense populations across three major mountains that were composed of seven genetically distinct subgroups. High pairwise FST values (mean FST = 0.35; highest FST = 0.55) suggested significant differentiation among populations. Overall within population genetic variation was low. Based on Mantel test, there was significant correlation between geographical and genetic distances indicating pattern of isolation by distance. Our results suggest that A. austrokoreense populations may have undergone recent population bottlenecks. Given the limited dispersal ability of the species and ongoing habitat fragmentation, population isolation may further be exacerbated leading to increased extinction risk.
RESUMO
We determined the complete chloroplast genome sequences of Aconitum austrokoreense Koidz., an endangered endemic species in Korea. The chloroplast DNA is 155,682 bp in length and encodes 37 tRNAs, 8 rRNAs, and 86 protein-coding genes. Phylogenetic analysis and sequence comparison of protein-coding genes with those in other Ranunculaceae chloroplast DNAs showed that the chloroplast genome of A. austrokoreense is closely related to that of A. chiisanense and large sequence variations identified in rps16, matK, and rpl20 are specific to these two species.