Genetic Diversity and Population Genetic Structure of Cinnamomum camphora in South China Revealed by EST-SSR Markers

Zhong Zhong,Zhang Zhang,Liu Liu,Wu Wu,Yu Yu,Li Li,Yang Yang,Xu Xu

doi:10.3390/f10111019

Abstract

Cinnamomum camphora is a valuable broad-leaf tree indigenous to South China and East Asia and has been widely cultivated and utilized by humans since ancient times. However, owing to its overutilization for essential oil extraction, the Transplanting Big Trees into Cities Program, and over deforestation to make furniture, its wild populations have been detrimentally affected and are declining rapidly. In the present study, the genetic diversity and population structure of 180 trees sampled from 41 populations in South China were investigated with 22 expressed sequence tag-simple sequence repeat (EST-SSR) markers. In total, 61 alleles were harbored across 180 individuals, and medium genetic diversity level was inferred from the observed heterozygosity (Ho), expected heterozygosity (He), and Nei’ gene diversity (GD), which were 0.45, 0.44, and 0.44, respectively. Among the 41 wild populations, C. camphora had an average of 44 alleles, 2.02 effective alleles, and He ranging from 0.30 (SC) to 0.61 (HK). Analysis of molecular variance (AMOVA) showed that 17% of the variation among populations and the average pairwise genetic differentiation coefficient (FST) between populations was 0.162, indicating relatively low genetic population differentiations. Structure analysis suggested two groups for the 180 individuals, which was consistent with the principal coordinate analysis (PCoA) and unweighted pair-group method with arithmetic means (UPGMA). Populations grouped to cluster I were nearly all distributed in Jiangxi Province (except population XS in Zhejiang Province), and cluster II mainly comprised populations from other regions, indicating a significant geographical distribution. Moreover, the Mantel test showed that this geographical distance was significantly correlated with genetic distance. The findings of this research will assist in future C. camphora conservation management and breeding programs.

Highlights

The Cinnamomum L. (Lauraceae) genus of tree species is ecologically and economically important and includes approximately 250 species that are widely distributed in the tropical and subtropical regions of Asia and South America [1,2]
This study provides an initial assessment of the genetic diversity and population structure of
The results showed medium genetic diversity and low genetic differentiation among populations

Summary

Introduction

The Cinnamomum L. (Lauraceae) genus of tree species is ecologically and economically important and includes approximately 250 species that are widely distributed in the tropical and subtropical regions of Asia and South America [1,2]. Forests 2019, 10, 1019 throughout human history because of their essential oils Among these species, Cinnamomum camphora is a broad-leaf tree species indigenous to South China, including Fujian, Zhejiang, Guangdong, Hubei, Guizhou, and especially Jiangxi Provinces [3,4], and East Asia [5]. Cinnamomum camphora is a broad-leaf tree species indigenous to South China, including Fujian, Zhejiang, Guangdong, Hubei, Guizhou, and especially Jiangxi Provinces [3,4], and East Asia [5] It has been introduced into a number of countries—including Australia, southeastern France, Madagascar, the Canary Islands, and the United States [6,7,8,9]. The fruits, wood, roots, bark, and leaves have been used in traditional herbal medicine as dietary supplements, perfume, health care products, and incense since the Han

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