Revealing the Genetic Structure in Endangered Species of Huangxin (Catalpa) by RAD Genotyping

Abstract

Abstract Huangxin is a type of Catalpa fargesii Bur. f. duclouxii (Dode) Gilmour, a small distribution species that have been over-exploited and damaged because of its excellent wood properties. Based on RAD-seq technique to evaluate the phylogeny, genetic diversity, genetic structure, gene flow, and extension routes of 169 individuals of Huangxin, and we used 24 samples of C. duclouxii and 5 Catalpa ovata G.Don samples as outgroups. In this study, we have explored the relationship between Huangxin with C. duclouxii and C. ovata, which proved that Huangxin is a separate species. Results of SNP analysis showed that the overall genetic diversity of Huangxin was moderate (mean HE=0.2935, HO=0.4401), and within the Huangxin subgroups, Subgroup 5 (HE=0.3011, HO=0.4495) had high genetic diversity. The FST value (mean = 0.1983) proves that a high level of genetic differentiation between subgroups. Furthermore, we found that the Huangxin population was strongly influenced by human activities. Therefore, strategies for in-situ and ex-situ protection of Huangxin are proposed, and these strategies are of great value for the conservation, preservation, and genetic improvement of this species. Meanwhile, it also provides a valuable reference for the conservation of other similar species with small ranges.