Polyploids contribute substantially to plant evolution and biodiversity;however,the mechanisms by which they succeed are still unclear.According to the polyploid adaptation hypothesis,successful polyploids spread by r...Polyploids contribute substantially to plant evolution and biodiversity;however,the mechanisms by which they succeed are still unclear.According to the polyploid adaptation hypothesis,successful polyploids spread by repeated adaptive responses to new environments.Here,we tested this hypothesis using two tetraploid yellowcresses(Rorippa),the endemic Rorippa elata and the widespread Rorippa palustris,in the temperate biodiversity hotspot of the Hengduan Mountains.Speciation modes were resolved by phylogenetic modeling using 12 low-copy nuclear loci.Phylogeographical patterns were then examined using haplotypes phased from four plastid and ITS markers,coupled with historical niche reconstruction by ecological niche modeling.We inferred the time of hybrid origins for both species as the mid-Pleistocene,with shared glacial refugia within the southern Hengduan Mountains.Phylogeographic and ecological niche reconstruction indicated recurrent northward colonization by both species after speciation,possibly tracking denuded habitats created by glacial retreat during interglacial periods.Common garden experiment involving perennial R.elata conducted over two years revealed significant changes in fitness-related traits across source latitudes or altitudes,including latitudinal increases in survival rate and compactness of plant architecture,suggesting gradual adaptation during range expansion.These findings support the polyploid adaptation hypothesis and suggest that the spread of polyploids was aided by adaptive responses to environmental changes during the Pleistocene.Our results thus provide insight into the evolutionary success of polyploids in high-altitude environments.展开更多
Though Berberis(Berberidaceae)is widely distributed across the Eurasian landmass it is most diverse in the Himalaya-Hengduan Mountain(HHM)region.There are more than 200 species in China where it is one of the most com...Though Berberis(Berberidaceae)is widely distributed across the Eurasian landmass it is most diverse in the Himalaya-Hengduan Mountain(HHM)region.There are more than 200 species in China where it is one of the most common mountain shrubs.The study on the taxonomy and evolution of Berberis in this region can thus provide an important insight into the origin and diversification of its flora.A prerequisite to this is mapping and describing the various species of Berberis in the region-a task that despite recent progress is by no means complete.It is clear that in China there may be a significant number of species still to be described and that even with published species much about their distribution remains to be discovered.As a contribution to the first of these tasks seven new species from the northern Hengduan Mountain of N.Sichuan and S.Qinghai:Berberis chinduensis,Berberis degexianensis,Berberis jiajinshanensis,Berberis jinwu,Berberis litangensis,Berberis longquensis and Berberis riparia,are described here.Differences in overall morphology and especially in floral structures with each other and with similar species of Berberis in the same region are presented.The report is the result of phylogenetic analyses based on plastome and partial nrDNA sequences of both the seven proposed new species and a significant number of similar species already published.Provisional conclusions as to the insights provides on the history of the genetic divergence are discussed.展开更多
Global climate change poses a severe threat to mountain biodiversity.Phenotypic plasticity and local adaptation are two common strategies for alpine plant to cope with such change.They may facilitate organismal adapta...Global climate change poses a severe threat to mountain biodiversity.Phenotypic plasticity and local adaptation are two common strategies for alpine plant to cope with such change.They may facilitate organismal adaptation to contrasting environments,depending on the influences of the environment or genotype or their interacted effects.In this study,we use an endemic alpine plant(Rorippa elata)in the Hengduan mountains(HDM)to unravel its phenotypic basis of adaptation strategy and evaluate the relative contributions of environment and genotype to its phenotype.We transplanted 37 genotypes of R.elata into two common gardens across low and high elevations(2800 vs.3800 m)during 2021-2022.Nine fitness-related traits were measured,including flowering probability and glucosinolates(GS)content.We estimated the environmental or genotypic contributions to the phenotype and identified the main environmental components.Our results revealed that both environment and genotype-by-environment interactions contributed to the phenotypes of R.elata.Latitudinal heterogeneity was identified as a key factor that explained 24%of the total phenotypic variation.In particular,genotypes of the northern HDM showed significantly higher plasticity in flowering probability than those of the southern HDM.Furthermore,within the southern HDM,GS content indicated local adaptation to herbivory stresses for R.elata genotypes along elevations.In conclusion,our results suggest that R.elata may have adapted to the alpine environment through species-level plasticity or regional-level local adaptation.These processes were shaped by either complex topography or interactions between genotype and mountain environments.Our study provides empirical evidence on the adaptation of alpine plants.展开更多
基金supported by the National Natural Science Foundation of China(31800177,32170224,and U1802242)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB31000000)+2 种基金T-S.H.is also supported by the Youth Innovation Promotion Association CAS(2020391)China Scholarship Council(201804910061)CAS Light of West China Program.We acknowledge Ya-Long Guo at the Institute of Botany CAS for providing Capsella rubella seeds and revising the manuscript.
文摘Polyploids contribute substantially to plant evolution and biodiversity;however,the mechanisms by which they succeed are still unclear.According to the polyploid adaptation hypothesis,successful polyploids spread by repeated adaptive responses to new environments.Here,we tested this hypothesis using two tetraploid yellowcresses(Rorippa),the endemic Rorippa elata and the widespread Rorippa palustris,in the temperate biodiversity hotspot of the Hengduan Mountains.Speciation modes were resolved by phylogenetic modeling using 12 low-copy nuclear loci.Phylogeographical patterns were then examined using haplotypes phased from four plastid and ITS markers,coupled with historical niche reconstruction by ecological niche modeling.We inferred the time of hybrid origins for both species as the mid-Pleistocene,with shared glacial refugia within the southern Hengduan Mountains.Phylogeographic and ecological niche reconstruction indicated recurrent northward colonization by both species after speciation,possibly tracking denuded habitats created by glacial retreat during interglacial periods.Common garden experiment involving perennial R.elata conducted over two years revealed significant changes in fitness-related traits across source latitudes or altitudes,including latitudinal increases in survival rate and compactness of plant architecture,suggesting gradual adaptation during range expansion.These findings support the polyploid adaptation hypothesis and suggest that the spread of polyploids was aided by adaptive responses to environmental changes during the Pleistocene.Our results thus provide insight into the evolutionary success of polyploids in high-altitude environments.
基金supported by the National Natural Science Foundation of China(U1802242)the Chinese Academy of Sciences Taiwan Young Talent Programme(2018TW2SB0002).
文摘Though Berberis(Berberidaceae)is widely distributed across the Eurasian landmass it is most diverse in the Himalaya-Hengduan Mountain(HHM)region.There are more than 200 species in China where it is one of the most common mountain shrubs.The study on the taxonomy and evolution of Berberis in this region can thus provide an important insight into the origin and diversification of its flora.A prerequisite to this is mapping and describing the various species of Berberis in the region-a task that despite recent progress is by no means complete.It is clear that in China there may be a significant number of species still to be described and that even with published species much about their distribution remains to be discovered.As a contribution to the first of these tasks seven new species from the northern Hengduan Mountain of N.Sichuan and S.Qinghai:Berberis chinduensis,Berberis degexianensis,Berberis jiajinshanensis,Berberis jinwu,Berberis litangensis,Berberis longquensis and Berberis riparia,are described here.Differences in overall morphology and especially in floral structures with each other and with similar species of Berberis in the same region are presented.The report is the result of phylogenetic analyses based on plastome and partial nrDNA sequences of both the seven proposed new species and a significant number of similar species already published.Provisional conclusions as to the insights provides on the history of the genetic divergence are discussed.
基金supported by the National Natural Science Foundation of China(32170224,32225005)the NSFC-ERC International Cooperation and Exchange Programs(32311530331)the Youth Innovation Promotion Association CAS(2020391).
文摘Global climate change poses a severe threat to mountain biodiversity.Phenotypic plasticity and local adaptation are two common strategies for alpine plant to cope with such change.They may facilitate organismal adaptation to contrasting environments,depending on the influences of the environment or genotype or their interacted effects.In this study,we use an endemic alpine plant(Rorippa elata)in the Hengduan mountains(HDM)to unravel its phenotypic basis of adaptation strategy and evaluate the relative contributions of environment and genotype to its phenotype.We transplanted 37 genotypes of R.elata into two common gardens across low and high elevations(2800 vs.3800 m)during 2021-2022.Nine fitness-related traits were measured,including flowering probability and glucosinolates(GS)content.We estimated the environmental or genotypic contributions to the phenotype and identified the main environmental components.Our results revealed that both environment and genotype-by-environment interactions contributed to the phenotypes of R.elata.Latitudinal heterogeneity was identified as a key factor that explained 24%of the total phenotypic variation.In particular,genotypes of the northern HDM showed significantly higher plasticity in flowering probability than those of the southern HDM.Furthermore,within the southern HDM,GS content indicated local adaptation to herbivory stresses for R.elata genotypes along elevations.In conclusion,our results suggest that R.elata may have adapted to the alpine environment through species-level plasticity or regional-level local adaptation.These processes were shaped by either complex topography or interactions between genotype and mountain environments.Our study provides empirical evidence on the adaptation of alpine plants.
