Abstract
Pseudosasa gracilis(Poaceae:Bambusoideae)is a temperate woody bamboo species endemic to South-central China with a narrow distribution.Previous phylogenetic studies revealed an unexpected,iso-lated phylogenetic position of Ps.gracilis.Here we conducted phylogenomic analysis by sampling pop-ulations of Ps.gracilis and its sympatric species Ps.nanunica and Sinosasa polytricha reflecting different genomic signals,by deep genome skimming.Integrating molecular evidence from chloroplast genes and genome-wide SNPs,we deciphered the phylogenetic relationships of Ps.gracilis.Both plastid and nuclear data indicate that Ps.gracilis is more closely related to Sinosasa,which is discordant with the taxonomic treatment.To further explore this molecular-morphological conflict,we screened 411"perfect-copy"syntenic genes to reconstruct phylogenies using both the concatenation and coalescent methods.We observed extensive discordance between gene trees and the putative species tree.A significant hy-bridization event was detected based on 411 genes from the D subgenome,showing Ps.gracilis was a hybrid descendant between Sinosasa longiligulata and Ps.nanunica,with 63.56％and 36.44％inheritance probabilities of each parent.Moreover,introgression events were detected in the C subgenome between Ps.gracilis and S.polytricha in the same distribution region.Our findings suggest that sympatric hy-bridization and introgression play a crucial role in the origin of Ps.gracilis.By providing an empirical example of bamboo of hybrid origin using comprehensive analyses based on genomic data from different inheritance systems and morphological characters,our study represents a step forward in understanding of reticulate evolution of bamboos.
基金项目
Strategic Priority Research Program of the Chinese Academy of Sciences(XDB31000000)
National Natural Science Foundation of China(32200193)
国家科技期刊平台
NSTL
万方数据