Genetic Diversity of Carpinus tientaiensis Cheng, an Endemic and Critically Endangered Species in China, Based on ITS Sequences

Abstract

The habitat of Carpinus tientaiensis Cheng (Betulaceae), an endemic endangered species in China, has been severely damaged, and it is in danger of going extinct. It is of great practical significance to propose corresponding protection measures based on population genetic variation. Based on the nuclear internal transcribed spacer (ITS) sequences, this study discovered that C. tientaiensis has relatively high genetic diversity at the species level. At the population level, the genetic variation levels of each population were not consistent, and the genetic diversity of the northern populations was higher than that of the southern populations. There was no significant genetic differentiation and phylogeographic structure among ribotypes and populations. Phylogenetic analysis showed that Sect. Distegocarpus and Sect. Carpinus were two independent genetic groups among the Carpinus, and C. tientaiensis may be the more evolutionary species in the Sect. Carpinus. Therefore, this study inferred that while C. tientaiensis has certain adaptability, climate change and human interference have brought it to an endangered state. Its populations may experienced the bottleneck effect, after which the expansion time was too short, with the populations failing to form a complex genetic structure. In addition, Tiantai Mountain was probably the original community and center of C. tientaiensis.