Low genetic diversity and population differentiation in Thuja sutchuenensis Franch., an extremely endangered rediscovered conifer species in southwestern China

Aili Qin; Yamei Ding; Zunji Jian; Fanqiang Ma; James R.P. Worth; Shunxiang Pei; Gexi Xu; Quanshui Guo; Zuomin Shi

Global Ecology and Conservation (Jan 2021)

Low genetic diversity and population differentiation in Thuja sutchuenensis Franch., an extremely endangered rediscovered conifer species in southwestern China

Aili Qin,
Yamei Ding,
Zunji Jian,
Fanqiang Ma,
James R.P. Worth,
Shunxiang Pei,
Gexi Xu,
Quanshui Guo,
Zuomin Shi

Affiliations

Aili Qin: Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Key Laboratory of Biodiversity Conservation of National Forestry and Grassland Administration, Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Beijing, 100091, China
Yamei Ding: State Key Laboratory of Earth Surface Processes and Resource Ecology and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
Zunji Jian: Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Key Laboratory of Biodiversity Conservation of National Forestry and Grassland Administration, Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Beijing, 100091, China
Fanqiang Ma: Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Key Laboratory of Biodiversity Conservation of National Forestry and Grassland Administration, Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Beijing, 100091, China
James R.P. Worth: Department of Forest Molecular Genetics and Biotechnology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki, 305-8687, Japan
Shunxiang Pei: Experimental Centre of Forestry in North China, Chinese Academy of Forestry, Beijing, 100091, China
Gexi Xu: Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Key Laboratory of Biodiversity Conservation of National Forestry and Grassland Administration, Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Beijing, 100091, China
Quanshui Guo: Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Key Laboratory of Biodiversity Conservation of National Forestry and Grassland Administration, Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Beijing, 100091, China; Corresponding author.
Zuomin Shi: Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Key Laboratory of Biodiversity Conservation of National Forestry and Grassland Administration, Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Beijing, 100091, China; Corresponding author.

Journal volume & issue: Vol. 25
p. e01430

Abstract

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Thuja sutchuenensis Franch. is an extremely endangered conifer (Cupressaceae) species that is endemic to southwestern China. It was once considered extinct in the wild and was rediscovered after 100 years later in October 1999. Due to the habitat destruction from nature and humans, the population has decreased sharply and the distribution range is narrow. Thus there is an urgent need to evaluate genetic variation within this species in order to establish a feasible conservation strategy. In this study, we used six single-copy nuclear loci (4CL, LEAFY, NEEDLY, CC1147, GAPC and RABGGTB) to investigate the genetic diversity, population structure and dynamics of T. sutchuenensis based on a sampling of 109 individuals from 6 natural populations across the known extant geographical range. Our results indicated that the genetic diversity of T. sutchuenensis was relatively lower (πt = 0.00219, θwt = 0.00240) than that of other Cupressaceae species. Extensive gene flow (Nm ≥ 11.07) and low genetic differentiation among populations were detected. Extended Bayesian skyline plots revealed that the population size of T. sutchuenensis has remained constant through time. The low genetic diversity was believed to result primarily from genetic drift caused by habitat fragmentation and population dynamics caused by climate fluctuations. The low genetic differentiation among populations was largely attributed to high levels of gene flow and small geographic distribution. Based on the above analyses, we should first conserve all extant populations and their habitats to maintain its current genetic diversity. Besides these, artificial propagation efforts such as seed propagation, cuttage breeding or tissue culture methods should be made to rescue this rare and endangered tree species.

Published in Global Ecology and Conservation

ISSN: 2351-9894 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Science: Biology (General): Ecology
Website: http://www.journals.elsevier.com/global-ecology-and-conservation/

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