Allopolyploid origin and niche expansion of Rhodiola integrifolia(Crassulaceae)  

作　　者：Da-Lv Zhong Yuan-Cong Li Jian-Qiang Zhang 

机构地区：[1]National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China,College of Life Sciences,Shaanxi Normal University,No.620,West Chang’an Avenue,Chang'an District,Xi’an,710119,China

出　　处：《Plant Diversity》2023年第1期36-44,共9页植物多样性（英文版）

基　　金：supported by the Fundamental Research Funds for the Central University of Shaanxi Normal University (GK202103077 to J.Q,Zhang);the National Natural Science Foundation of China(Grant nos.31870194,32070236)。

摘　　要：Polyploidy after hybridization between species can lead to immediate post-zygotic isolation,causing saltatory origin of new species.Although the incidence of polyploidization in plants is high,it is thought that a new polyploid lineage can succeed only if it establishes a new ecological niche divergent from its progenitor lineages.We tested the hypothesis that Rhodiola integrifolia from North America is an allopolyploid produced by R. rhodantha and R.rosea and determined whether its survival can be explained by the niche divergence hypothesis.To this end,we sequenced two low-copy nuclear genes(ncpGS and rpb2) in a phylogenetic analysis of 42 Rhodiola species and tested for niche equivalency and similarity using Schoener’s D as the index of niche overlap.Our phylogeny-based approach showed that R integrifolia possesses alleles from both R. rhodantha and rosea Dating analysis showed that the hybridization event that led to R.integrifolia occurred ca.1.67 Mya and niche modeling analysis showed that at this time,both R.rosea and R.rhodantha may have been present in Beringia,providing the opportunity for the hybridization event.We also found that the niche of R.integrifolia differs from that of its progenitors in both niche breadth and optimum.Taken together,these results confirm the hybrid origin of R.integrifolia and support the niche divergence hypothesis for this tetraploid species.Our results underscore the fact that lineages with no current overlapping distribution could produce hybrid descendants in the past,when climate oscillations made their distributions overlap.

关 键 词：ALLOPOLYPLOID HYBRIDIZATION ncpGS Niche shift rpb2 Schoener’s D 

分 类 号：Q943[生物学—植物学]