| East Asian flora is one of global biodiversity hotspots that attracted biologists and biogeographers.Complicated historical processes including the uplift of Qinghai-Xizang(Tibet)Plateau,the monsoon climate,and the Quaternary glacial period have occurred in this region.Moreover,complex terrain contains the rivers system and the mountains causing the multiple potential biological boundaries of geographical and ecological barriers.In the recent years,interdisciplinary-based studies have improved our macro-cognition of the origin and evolution of East Asian flora at the species level.With the development of molecular phylogeny and biogeography,studies on the East Asian flora about genomic level have increasingly captured considerable attention.Therefore,current study integrated multiple taxa to be representatives of different subregions,life forms,habitats and dispersal format in the East Asian Flora(Theligonum,Myripnois,Parasyncalathium souliei,and Adenocaulon himalaicum)using multiple loci,plastome and RAD-seq to explore: 1)plastome structural variation and evolution among featured taxa;2)we further investigated the demographic history and the drivers for population evolution;3)we used the phylogeoregion to propose a new scheme by meta-analysis.Detailed results are as follows:1)Theligonum(Rubiaceae)Theligonum with four species are mainly distributed in East Asia.Due to extreme habitat and altitude differentiation among species,Theligonum provides an opportunity to explore the infrageneric structural plastome evolution.Results of plastome comparisons showed the content and structure are highly conserved among species although variation was found in the genome size.Combined with climate variables,gene selection pressure,and evolutionary history,we suggested the conserved plastomes among Theligonum species are associated with recent diversification and purifying selection.Meanwhile,our phylogenomic and biogeographic pattern among Theligonum inferred that East Sea and Taiwan,China landbridge served as potential biogeographic barrier promoting species differentiation.2)Myripnois(Asteraceae)Myripnois is a monotypic shrub genus in the daisy family with only one species Myripnois dioica that is constricted to northern China of Sino-Japanese Forest subkingdom.Using RAD-seq from 77 samples and 16 populations,our results revealed that the current northern and southern groups representing two distinct lineages were affected by the Taihang mountains of biological geographical barriers,Quaternary climate change and together with the local adaptation associated with drought.Meanwhile,we tested joint effects of expansion dynamic history and environmental factors on effective population size(Ne)change.A multiple linear regression analysis revealed Ne is correlated with population age,mean temperature of coldest quarter and precipitation of wettest month.Based on phylogeographic pattern,we supported the Taihang mountains as a potential phylogeographic boundary in the Sino-Japanese Forest subkingdom promoting species differentiation.3)Parasyncalathium souliei(Asteraceae)Parasyncalathium souliei is the only specie from this genus with a widespread distribution of the Qinghai-Xizang(Tibet)Plateau and Hengduan Mountains.Based on 417 individuals in 36 populations across the geographic range of the species significant phylogeographic structure was found among populations(NST>GST;P<0.05)caused by uplift of Qinghai-Xizang(Tibet)Plateau,and the Quaternary glacial.Four major haplogroups generally corresponded to previously identified biogeographic subregions.Our results supported that the Jinsha-Nu Rivers and the 29?N are regarded as the phylogeographical boundaries of the eastern Himalayan region and the Hengduan Mountain region as well as the South-North Hengduan Mountain regions.4)Adenocaulon himalaicum(Asteraceae)Adenocaulon himalaicum is the only species of Adenocaulon widely distributed in East Asian flora and it distinguished from other daisy family herb by its unique glandular seeds.Based on 19 populations from 133 individuals,our results revealed interaction of ecological barrier,historical climatic,and local adaption have contributed to current phylogeographic pattern A.himalaicum.Our results supported the northern East Asian flora origin of A.himalaicum,the aridity belt in East Asian flora served as an ecological barrier have caused initial divergence between northern populations and central populations,and the forming of allopatric refugia during Pleistocene further separated central populations and southern population.We also find the important role of environmental adaptation related to drought and salt stress have maintained the recent divergence events.Moreover,the Sichuan Basin and aridity belt have served as potential ecological barriers and phylogeographic boundaries to populations divergence.5)Phylogeoregion backbone of East Asian floraWe incorporated phylogeographic information into regionalization schemes and provide novel insights into the traditional regionalization.Concretely,we integrated detailed phylogeographic hapgroups and structure of multiple species and combined them into geological,climate and environmental change to provide new phylogeoboundaries and phylogeoregions in East Asian Flora.We further estimated the the possible reasons for these phylogeoboundaries by assessing plant divergent time.We inferred the formation of the phylogeoboundaries were related to the biogeographic and ecological barriers,the uplift of Qinghai-Xizang(Tibet)Plateau,and the Quaternary climate change and the monsoon and dry barrier systems.In conclusion,our results supported geographical and ecological barriers,historical climate change and local adaptation to the ecological environment together have driven the pant divergence in East Asian flora,and phylogeographic structure representing the evolutionary history and dynamic changes of different species can provide a new scheme for regionalization.Our current studies based on meta-analysis will contributed to understanding of East Asian flora. |
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