Genomic divergence and mutation load in the Begonia masoniana complex from limestone karsts  

作　　者：Yiqing Chen Lina Dong Huiqin Yi Catherine Kidner Ming Kang 

机构地区：[1]Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China,Guangzhou 510650,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Guangxi Key Laboratory of Conservation and Restoration Ecology in Karst Terrain,Guangxi Institute of Botany,Guangxi Zhang Autonomous Region and the Chinese Academy of Sciences,Guilin 541006,China [4]Institute of Molecular Plant Sciences,University of Edinburgh,Daniel Rutherford Building Max Born Crescent,The King's Buildings,Edinburgh EH93BF,UK [5]Royal Botanic Garden Edinburgh,20a Inverleith Row,Edinburgh EH35LR,UK [6]State Key Laboratory of Plant Diversity and Specialty Crops,South China Botanical Garden,Chinese Academy of Sciences,Guangzhou 510650,China

出　　处：《Plant Diversity》2024年第5期575-584,共10页植物多样性（英文版）

基　　金：supported by Key-Area Research and Development Program of Guangdong Province(Grant No.2022B1111230001);National Natural Science Foundation of China(31860048).

摘　　要：Understanding genome-wide diversity,inbreeding,and the burden of accumulated deleterious mutations in small and isolated populations is essential for predicting and enhancing population persistence and resilience.However,these effects are rarely studied in limestone karst plants.Here,we re-sequenced the nuclear genomes of 62 individuals of the Begonia masoniana complex(B.liuyanii,B.longgangensis,B.masoniana and B.variegata)and investigated genomic divergence and genetic load for these four species.Our analyses revealed four distinct clusters corresponding to each species within the complex.Notably,there was only limited admixture between B.liuyanii and B.longgangensis occurring in overlapping geographic regions.All species experienced historical bottlenecks during the Pleistocene,which were likely caused by glacial climate fluctuations.We detected an asymmetric historical gene flow between group pairs within this timeframe,highlighting a distinctive pattern of interspecific divergence attributable to karst geographic isolation.We found that isolated populations of B.masoniana have limited gene flow,the smallest recent population size,the highest inbreeding coefficients,and the greatest accumulation of recessive deleterious mutations.These findings underscore the urgency to prioritize conservation efforts for these isolated population.This study is among the first to disentangle the genetic differentiation and specific demographic history of karst Begonia plants at the whole-genome level,shedding light on the potential risks associated with the accumulation of deleterious mutations over generations of inbreeding.Moreover,our findings may facilitate conservation planning by providing critical baseline genetic data and a better understanding of the historical events that have shaped current population structure of rare and endangered karst plants.

关 键 词：Conservation genomics Karst landscape Demographic history INBREEDING Isolated populations Mutation load 

分 类 号：Q943[生物学—植物学]