Population Genetics of the Endangered and Wild Edible Plant Ottelia acuminata in Southwestern China Using Novel SSR Markers

Abstract

Ottelia acuminata is an edible aquatic plant species that is endemic to southwestern China. This plant has experienced habitat degradation resulting from environmental change and extensive human disturbance. Determining the genetic variation and genetic structure of O. acuminata populations could help develop strategies to collect, evaluate, utilize and conserve the species. To this end, we genotyped 183 individuals sampled throughout the species distribution using twelve novel nuclear microsatellite loci (nSSRs). Eight of these nSSRs exhibited low average levels of genetic diversity (HE=0.351, Ho=0.376) and showed evidence of significant inbreeding across several populations. A high degree of genetic differentiation was identified among populations (FST=0.457), probably resulting from limited pollen and seed-mediated gene flow. Only 17.8% of variation existed between O. acuminata var. acuminata and other O. acuminata varieties. Bayesian analysis and a UPGMA dendrogram based on Nei's genetic distance also revealed notably low genetic differentiation among the varieties. This low genetic differentiation is possibly attributed to shared ancestral polymorphisms since their divergence. Additional taxonomic and phylogenetic studies with additional molecular markers are needed to determine the population genetic relationship between O. acuminata varieties. Conservation of this species depends on in situ and ex situ actions, such as controlling habitat water pollution and overexploitation and creating a germplasm bank based on the population genetic differences. To the best of our knowledge, this study represents the first attempt to understand the population genetics of O. acuminata in China using novel nSSR markers developed from transcriptome sequencing and could contribute to the conservation management of this economic plant.