Genetic Diversity and Population Differentiation of Calanthe tsoongiana, a Rare and Endemic Orchid in China

Xin Qian,Cai-Xia Wang,Min Tian

doi:10.3390/ijms141020399

Xin Qian, Cai-Xia Wang + Show 1 more

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https://doi.org/10.3390/ijms141020399

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Abstract

Calanthe tsoongiana is a rare terrestrial orchid endemic to China, and this species has experienced severe habitat loss and fragmentation. Inter-simple sequence repeat (ISSR) markers were employed to assess the genetic diversity and differentiation of six populations of C. tsoongiana. Based on 124 discernible fragments yielded by eleven selected primers, high genetic diversity was revealed at the species level; however, genetic diversity at the population level was relatively low. High-level genetic differentiation among populations was detected based on analysis of molecular variance (AMOVA), indicating potential limited gene flow. No significant relationship was observed between genetic and geographic distances among the sampled populations. These results suggested that restricted gene flow might be due to habitat fragmentation and reduced population size as a result of human activities. Based on the findings, several conservation strategies were proposed for the preservation of this threatened species.

Highlights

Orchidaceae is one of the largest families of flowering plants, with approximately 25,000 species comprising up to 10% of all angiosperms, including five subfamilies and about 870 genera [1]
104 individuals from six C. tsoongiana populations generated 124 clear and discernible bands using eleven selected Inter-simple sequence repeat (ISSR) primers, of which 120 (96.8%) were polymorphic (Table 1). This indicated that the ISSR markers measured sufficient polymorphism for DNA typing in the population genetic study of C. tsoongiana
Genetic diversity was relatively low at the population level and shifted variably across different sites

Summary

Introduction

Orchidaceae is one of the largest families of flowering plants, with approximately 25,000 species comprising up to 10% of all angiosperms, including five subfamilies and about 870 genera [1]. Br., is widely distributed in tropical, subtropical and warm temperate regions from Africa to Asia and the Pacific Islands It is characterized by distichous plicate leaves, basal or lateral inflorescences, pseudobulbous or cane-like stems made up of several internodes, similar petals and sepals, normally spurred lips and possession of eight pollinia [2]. This genus contains approximately 171 species worldwide, 40 of which inhabit China [2]. Many populations recorded previously have disappeared, and current distributions are highly fragmented and isolated This species has been listed as a national second class protection species in China [4]. To date, nothing is known about its within-population or its intra-specific genetic diversity and population structure among the distribution areas

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