Change of flower color can readily lead to a shift in pollinators,potentially causing pollinator mediated reproductive isolation or even speciation.Here,we examined the ecological and evolutionary consequences of flow...Change of flower color can readily lead to a shift in pollinators,potentially causing pollinator mediated reproductive isolation or even speciation.Here,we examined the ecological and evolutionary consequences of flower color polymorphism in Roscoea cautleoides,an alpine ginger with sympatric distribution of purple-and yellow-flowered plants.Variations in pollinator visitation and specialization to the flower color contributed greatly to pre-zygotic reproductive isolation,with post-zygotic isolation also observed in reciprocal pollination.Yellow-flowered plants evolved independently from purple-flowered plants in two populations due to the absence of anthocyanins,as supported by metabolic,expression,and genetic analysis.Despite early genetic divergence between the two-flower-colored plants,highly differentiated genes were associated with reproduction and stress,while highly selective genes were enriched in stress.Our results suggest that parallel loss of anthocyanins leads to flower color polymorphism in different populations of R.cautleoides,with pollinator preference contributing to reproductive isolation and subsequent genetic differentiation,indicating the process of incipient speciation triggered by flower color changes with sympatric distribution.展开更多
Delimiting species requires multiple sources of evidence.Here,we delimited two varieties of Halenia elliptica(Gentianaceae)using several lines of evidence,including morphological traits and mating system in a sympatri...Delimiting species requires multiple sources of evidence.Here,we delimited two varieties of Halenia elliptica(Gentianaceae)using several lines of evidence,including morphological traits and mating system in a sympatric population,phylogenetic relationships based on nrITS and cpDNA(rpl16)data,and complete chloroplast genome sequences.Comparative analysis of 21 morphological traits clearly separates the two varieties of H.elliptica.Examination of the flowering process and pollination treatments indicate that H.elliptica var.grandiflora produces seeds via outcrossing,whereas H.elliptica var.elliptica produces seeds via mixed mating.Furthermore,hand-pollinated hybridization of the two varieties produced no seeds.Observations of pollinators showed that when bees began a pollination bout on H.elliptica var.grandiflora they preferred to continue pollinating this variety;however,when they began a pollination bout on H.elliptica var.elliptica,they showed no preference for either variety.Phylogenetic analysis confirmed the monophyly of H.elliptica,which was further divided into two monophyletic clades corresponding to the two varieties.A large number of variants from the chloroplast genomes reflected remarkable genetic dissimilarities between the two varieties of H.elliptica.We recommend that the two varieties of H.elliptica should be revised as two species(H.elliptica and H.grandiflora).Our findings indicate that H.elliptica varieties may have split into two separate species due to a shift in mating system,changes in flowering phenology and/or post-pollination reproductive isolation.展开更多
The complex interactions of historical,geological and climatic events on plant evolution have been an important research focus for many years.However,the role of desert formation and expansion in shaping the genetic s...The complex interactions of historical,geological and climatic events on plant evolution have been an important research focus for many years.However,the role of desert formation and expansion in shaping the genetic structures and demographic histories of plants occurring in arid areas has not been well explored.In the present study,we investigated the phylogeography of Arnebia szechenyi,a desert herb showing a near-circular distribution surrounding the Tengger Desert in Northwest China.We measured genetic diversity of populations using three maternally inherited chloroplast DNA(cpDNA)fragments and seven bi-paternally inherited nuclear DNA(nDNA)loci that were sequenced from individuals collected from 16 natural populations across its range and modelled current and historical potential habitats of the species.Our data indicated a considerably high level of genetic variation within A.szechenyi and noteworthy asymmetry in historical migration from the east to the west.Moreover,two nuclear genetic groups of populations were revealed,corresponding to the two geographic regions separated by the Tengger Desert.However,analysis of cpDNA data did not show significant geographic structure.The most plausible explanation for the discrepancy between our findings based on cpDNA and nDNA data is that A.szechenyi populations experienced long periods of geographic isolation followed by range expansion,which would have promoted generalized recombination of the nuclear genome.Our findings further highlight the important role that the Tengger Desert,together with the Helan Mountains,has played in the evolution of desert plants and the preservation of biodiversity in arid Northwest China.展开更多
基金supported by National Natural Science Foundation of China(32102429,32371586)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0502)+1 种基金the Yunnan Young Talent Project(YNWR-QNBJ-2019-214)the CAS-TWAS Presidents Fellowship to Tial Cung Ling.
文摘Change of flower color can readily lead to a shift in pollinators,potentially causing pollinator mediated reproductive isolation or even speciation.Here,we examined the ecological and evolutionary consequences of flower color polymorphism in Roscoea cautleoides,an alpine ginger with sympatric distribution of purple-and yellow-flowered plants.Variations in pollinator visitation and specialization to the flower color contributed greatly to pre-zygotic reproductive isolation,with post-zygotic isolation also observed in reciprocal pollination.Yellow-flowered plants evolved independently from purple-flowered plants in two populations due to the absence of anthocyanins,as supported by metabolic,expression,and genetic analysis.Despite early genetic divergence between the two-flower-colored plants,highly differentiated genes were associated with reproduction and stress,while highly selective genes were enriched in stress.Our results suggest that parallel loss of anthocyanins leads to flower color polymorphism in different populations of R.cautleoides,with pollinator preference contributing to reproductive isolation and subsequent genetic differentiation,indicating the process of incipient speciation triggered by flower color changes with sympatric distribution.
基金the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0502)National Key R&D Program of China(2017YFC0505200)+1 种基金National Natural Science Foundation of China(31460096 and 31590823)State Key Laboratory of Phytochemistry and Plant Resources in West China(P2020-KF04).
文摘Delimiting species requires multiple sources of evidence.Here,we delimited two varieties of Halenia elliptica(Gentianaceae)using several lines of evidence,including morphological traits and mating system in a sympatric population,phylogenetic relationships based on nrITS and cpDNA(rpl16)data,and complete chloroplast genome sequences.Comparative analysis of 21 morphological traits clearly separates the two varieties of H.elliptica.Examination of the flowering process and pollination treatments indicate that H.elliptica var.grandiflora produces seeds via outcrossing,whereas H.elliptica var.elliptica produces seeds via mixed mating.Furthermore,hand-pollinated hybridization of the two varieties produced no seeds.Observations of pollinators showed that when bees began a pollination bout on H.elliptica var.grandiflora they preferred to continue pollinating this variety;however,when they began a pollination bout on H.elliptica var.elliptica,they showed no preference for either variety.Phylogenetic analysis confirmed the monophyly of H.elliptica,which was further divided into two monophyletic clades corresponding to the two varieties.A large number of variants from the chloroplast genomes reflected remarkable genetic dissimilarities between the two varieties of H.elliptica.We recommend that the two varieties of H.elliptica should be revised as two species(H.elliptica and H.grandiflora).Our findings indicate that H.elliptica varieties may have split into two separate species due to a shift in mating system,changes in flowering phenology and/or post-pollination reproductive isolation.
基金supported by the National Natural Science Foundation of China(41861008)Science Foundation of Yunnan Education Department(2018JS347)the Ten-thousand Talents Program of Yunnan Province(YNWR-QNBJ-2020).
文摘The complex interactions of historical,geological and climatic events on plant evolution have been an important research focus for many years.However,the role of desert formation and expansion in shaping the genetic structures and demographic histories of plants occurring in arid areas has not been well explored.In the present study,we investigated the phylogeography of Arnebia szechenyi,a desert herb showing a near-circular distribution surrounding the Tengger Desert in Northwest China.We measured genetic diversity of populations using three maternally inherited chloroplast DNA(cpDNA)fragments and seven bi-paternally inherited nuclear DNA(nDNA)loci that were sequenced from individuals collected from 16 natural populations across its range and modelled current and historical potential habitats of the species.Our data indicated a considerably high level of genetic variation within A.szechenyi and noteworthy asymmetry in historical migration from the east to the west.Moreover,two nuclear genetic groups of populations were revealed,corresponding to the two geographic regions separated by the Tengger Desert.However,analysis of cpDNA data did not show significant geographic structure.The most plausible explanation for the discrepancy between our findings based on cpDNA and nDNA data is that A.szechenyi populations experienced long periods of geographic isolation followed by range expansion,which would have promoted generalized recombination of the nuclear genome.Our findings further highlight the important role that the Tengger Desert,together with the Helan Mountains,has played in the evolution of desert plants and the preservation of biodiversity in arid Northwest China.
