The Study of Genetic Diversity and Structure of Extremely Endangered Manglietia longipedunculata and Endangered Manglietia insignis

Abstract

Abstract To strengthen the protection of Manglietia insignis and Manglietia longipedunculata germplasm resources, the endangered mechanism and scientific protection strategies of these two species were investigated. A novel, effective, and flexible DNA sequencing library construction approach-Hyper-seq was used in this study to develop large-scale genomic single nucleotide polymorphism (SNP) and to evaluate the genetic diversity and population structure of M. insignis and M. longipedunculata. Genetic diversity analysis demonstrated that the genetic diversity of M. insignis, which expected heterozygosity (He) was 0.1435 and nucleotide diversity (π) was 0.1541.M. longipedunculata, lower than in M. longipedunculata (He= 0.1793, π = 0.1916) with narrow distribution. The genetic diversity of the two ex-situ conservation populations (He=0.1797, 0.1990, π = 0.1894, 0.2121 ) was higher than the wild populations (He=0.1591, π = 0.1733), suggesting that the artificial ex-situ conservation population can effectively protect its genetic diversity and the genetic breeding in future studies. The mean inbreeding coefficient (FIS) in the M. longipedunculata and M. insignis populations were − 0.0141 and − 0.0176, respectively, indicating that the two populations were largely outcrossing in the natural state. The frequency of rare alleles in M. insignis (Tajima's D = 0.3436 > 0) and M. longipedunculata (Tajima's D = 0.2119 > 0) populations was low, which may be under balanced selection pressure or experienced population shrinkage. A high degree of genetic differentiation between the two species was detected, but moderate among the populations of the same species. The results of cluster analysis demonstrated a obvious separation between the two species with all individuals clustering according to species differences. It is worth noting that individuals 7, 8, and 9 in the ML-CW M. insignis population first clustered with M. longipedunculata. Furthermore, these individuals also contained a small genetic component from M. longipedunculata. Principal component and genetic relationship analysis also demonstrated that some M. insignis individuals exhibited an evident genetic relationship with M. longipedunculata. These populations can therefore be preferentially selected in the further cross-breeding experiments of the two species. The genetic diversity and structure of M. insignis and M. longipedunculata were compared in this study. Not only were the genetic characteristics of the two species explored for the first time, but the genetic relationship between the two species was also preliminarily explored. This study provides a scientific basis for the development of future protection strategies at the molecular level.