Genome‐wide diversity evaluation and core germplasm extraction in ex situ conservation: A case of golden Camellia tunghinensis

Abstract

Whether ex situ populations constructed in the limited nursery resources of botanical gardens can preserve enough genetic diversity of endangered plants in the wild remains uncertain. Here, a case study was conducted with Camellia tunghinensis, which is one of the species with the lowest natural distribution area in the sect. Chrysantha (golden camellia) of the family Theaceae. We investigated the genetic diversity and population structure of 229 samples from wild and ex situ populations using genotyping by sequencing (GBS). Core germplasm was constructed from these samples. The results showed that wild C. tunghinensis exhibited high genetic diversity, with observed heterozygosity of 0.257–0.293 and expected heterozygosity of 0.247–0.262. Compared with wild populations, the genetic diversity of ex situ populations established by transplanting wild seedlings was close to or even higher. However, the genetic diversity of those established by seed or cuttings of a few superior trees was lower. The Admixture analysis revealed that the structure of the ex situ populations derived from seeds and cuttings was relatively simple compared with the ex situ populations derived from transplanted wild seedlings and wild populations. These results suggested that direct transplanting of wild seedlings was more conducive to preserving the genetic diversity of endangered plants in the wild. In addition, wild populations demonstrated a small differentiation (mean FST = 0.044) among themselves, possibly due to long‐term and frequent gene flow between the wild populations. In contrast, moderate differentiation (mean FST > 0.05) was detected among ex situ populations and between ex situ and wild populations. This may be the combined result of the absence of gene flow pathways and strong selection pressure in various ex situ environments. Finally, 77 core germplasms were extracted from 229, likely representing the genetic diversity of C. tunghinensis. This study provides future strategies for the ex situ conservation and management of the golden camellia species and other rare and endangered plants.

The Study of Genetic Diversity and Structure of Extremely Endangered Manglietia longipedunculata and Endangered Manglietia insignis

“…Comparison of genetic structure and differentiation between M. insignis and M. longipedunculata. The investigation of the genetic structure of species is very important for the protection of species and the formulation of protection strategies 40,41 . The M. longipedunculata and M. insignis clustering map demonstrated a few individual confounding phenomena between the two populations.…”

Evidence for the Use of Karst Tiankengs as Shelters: The Effect of Karst Tiankengs on Genetic Diversity and Population Differentiation in Manglietia aromatica

“…In the protection and management of endangered plants, ex situ conservation is used as an artificial means to manage and protect species whose native habitats have been destroyed [42,43]. However, because of the distance from their native environment, gene exchange between the ex situ population and the native population is greatly reduced, resulting in greater genetic differentiation [44,45].…”

Genotypic and Phenotypic Diversity of Endemic Golden Camellias Collected from China

“…The vcf-tools program was used based on the sliding window method (the window was set to 3 kb) to calculate the expected heterozygosity (He), nucleotide diversity (Nucleotide Diversity, Pi) and the inbreeding coefficient (Inbreeding Coefficient of an Individual Relative to the Subpopulation, Fis). Lastly, the Shannon-Wiener diversity index, shannon_Index, was used for analysis [25][26][27].…”

“…Research on the genetic diversity of golden camellia plant species in karst and non-karst areas will help reveal the factors influencing the phenotypic characteristics of Camellia Scet. Chrysantha plants [25]. The Shannon-Wiener diversity index is an index used to investigate the diversity (α-diversity) of plant communities in local habitats.…”