Conservation genetics of an endangered lady's slipper orchid: Cypripedium japonicum in China.

Xin Qian,Fen Liu,Min Tian,Mao-Jiang Gong,Cai-Xia Wang,Quan-Jian Li

doi:10.3390/ijms150711578

Abstract

Knowledge about the population genetic variation of the endangered orchid, Cypripedium japonicum, is conducive to the development of conservation strategies. Here, we examined the levels and partitioning of inter-simple sequence repeat (ISSR) diversity (109 loci) in five populations of this orchid to gain insight into its genetic variation and population structure in Eastern and Central China. It harbored considerably lower levels of genetic diversity both at the population (percentage of polymorphic loci (PPL) = 11.19%, Nei’s gene diversity (H) = 0.0416 and Shannon’s information index (I) = 0.0613) and species level (PPL = 38.53%, H = 0.1273 and I = 0.1928) and a significantly higher degree of differentiation among populations (the proportion of the total variance among populations (Φpt) = 0.698) than those typical of ISSR-based studies in other orchid species. Furthermore, the Nei’s genetic distances between populations were independent of the corresponding geographical distances. Two main clusters are shown in an arithmetic average (UPGMA) dendrogram, which is in agreement with the results of principal coordinate analysis (PCoA) analysis and the STRUCTURE program. In addition, individuals within a population were more similar to each other than to those in other populations. Based on the genetic data and our field survey, the development of conservation management for this threatened orchid should include habitat protection, artificial gene flow and ex situ measures.

Highlights

Population genetic analyses in the field of biological conservation have been the topic of considerable discussion; they are increasingly emphasized, because assessments of different levels of genetic diversity and population structure within species can increase the understanding of their evolutionary history and population dynamics, and they are critical for developing effective conservation management strategies [1]
The fourteen selected inter-simple sequence repeat (ISSR) primers chosen for analysis produced a total of 109 bands among
(0.6712) and the UPGMA and principal coordinate analysis (PCoA) results suggested limited gene flow, even between the less distant populations (TMS and DMS populations), as well as marked differentiation between populations, which was supported by the analysis of molecular variance (AMOVA) results (Φpt = 0.698), indicating that the majority of genetic diversity was explained by variation among populations

Summary

Introduction

Population genetic analyses in the field of biological conservation have been the topic of considerable discussion; they are increasingly emphasized, because assessments of different levels of genetic diversity and population structure within species can increase the understanding of their evolutionary history and population dynamics, and they are critical for developing effective conservation management strategies [1]. The existing evidence demonstrates that most Chinese orchid species have suffered dramatic declines in abundance, mostly due to over-collection and increased habitat fragmentation and destruction [3]. This reduces population sizes, which may lead to reduced gene flow and increased levels of inbreeding through random genetic drift, with a consequent loss of genetic diversity [4]. The long-term survival of any species requires the maintenance of sufficient genetic diversity to serve as the raw material for evolutionary changes in natural populations [5]

Methods

Results

Discussion

Conclusion