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Shi YJ, Mi JX, Huang JL, Tian FF, He F, Zhong Y, Yang HB, Wang F, Xiao Y, Yang LK, Zhang F, Chen LH, Wan XQ. A new species of Populus and the extensive hybrid speciation arising from it on the Qinghai-Tibet Plateau. Mol Phylogenet Evol 2024; 196:108072. [PMID: 38615706 DOI: 10.1016/j.ympev.2024.108072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 03/25/2024] [Accepted: 04/11/2024] [Indexed: 04/16/2024]
Abstract
While the diversity of species formation is broadly acknowledged, significant debate exists regarding the universal nature of hybrid species formation. Through an 18-year comprehensive study of all Populus species on the Qinghai-Tibet Plateau, 23 previously recorded species and 8 new species were identified. Based on morphological characteristics, these can be classified into three groups: species in section Leucoides, species with large leaves, and species with small leaves in section Tacamahaca. By conducting whole-genome re-sequencing of 150 genotypes from these 31 species, 2.28 million single nucleotide polymorphisms (SNPs) were identified. Phylogenetic analysis utilizing these SNPs not only revealed a highly intricate evolutionary network within the large-leaf species of section Tacamahaca but also confirmed that a new species, P. curviserrata, naturally hybridized with P. cathayana, P. szechuanica, and P. ciliata, resulting in 11 hybrid species. These findings indicate the widespread occurrence of hybrid species formation within this genus, with hybridization serving as a key evolutionary mechanism for Populus on the plateau. A novel hypothesis, "Hybrid Species Exterminating Their Ancestral Species (HSEAS)," is introduced to explain the mechanisms of hybrid species formation at three different scales: the entire plateau, the southeastern mountain region, and individual river valleys.
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Affiliation(s)
- Yu-Jie Shi
- College of Forestry, Sichuan Agricultural University, Chengdu 611130, China; Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou 318000, China
| | - Jia-Xuan Mi
- College of Forestry, Sichuan Agricultural University, Chengdu 611130, China
| | - Jin-Liang Huang
- College of Forestry, Sichuan Agricultural University, Chengdu 611130, China
| | - Fei-Fei Tian
- College of Forestry, Sichuan Agricultural University, Chengdu 611130, China
| | - Fang He
- College of Forestry, Sichuan Agricultural University, Chengdu 611130, China
| | - Yu Zhong
- College of Forestry, Sichuan Agricultural University, Chengdu 611130, China; Sichuan Province Key Laboratory of Ecological Forestry Engineering On the Upper Reaches of the Yangtze River, China
| | - Han-Bo Yang
- College of Forestry, Sichuan Agricultural University, Chengdu 611130, China; Sichuan Province Key Laboratory of Ecological Forestry Engineering On the Upper Reaches of the Yangtze River, China
| | - Fang Wang
- College of Forestry, Sichuan Agricultural University, Chengdu 611130, China
| | - Yu Xiao
- College of Forestry, Sichuan Agricultural University, Chengdu 611130, China
| | - Lin-Kai Yang
- College of Forestry, Sichuan Agricultural University, Chengdu 611130, China
| | - Fan Zhang
- College of Landscape Architecture, Sichuan Agricultural University, Chengdu 611130, China
| | - Liang-Hua Chen
- College of Forestry, Sichuan Agricultural University, Chengdu 611130, China; Sichuan Province Key Laboratory of Ecological Forestry Engineering On the Upper Reaches of the Yangtze River, China
| | - Xue Qin Wan
- College of Forestry, Sichuan Agricultural University, Chengdu 611130, China; Sichuan Province Key Laboratory of Ecological Forestry Engineering On the Upper Reaches of the Yangtze River, China.
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Zhang Z, Liu G, Li M. Incomplete lineage sorting and gene flow within Allium (Amayllidaceae). Mol Phylogenet Evol 2024; 195:108054. [PMID: 38471599 DOI: 10.1016/j.ympev.2024.108054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/01/2024] [Accepted: 03/07/2024] [Indexed: 03/14/2024]
Abstract
The phylogeny and systematics of the genus Allium have been studied with a variety of diverse data types, including an increasing amount of molecular data. However, strong phylogenetic discordance and high levels of uncertainty have prevented the identification of a consistent phylogeny. The difficulty in establishing phylogenetic consensus and evidence for genealogical discordance make Allium a compelling test case to assess the relative contribution of incomplete lineage sorting (ILS), gene flow and gene tree estimation error on phylogenetic reconstruction. In this study, we obtained 75 transcriptomes of 38 Allium species across 10 subgenera. Whole plastid genome, single copy genes and consensus CDS were generated to estimate phylogenetic trees both using coalescence and concatenation methods. Multiple approaches including coalescence simulation, quartet sampling, reticulate network inference, sequence simulation, theta of ILS and reticulation index were carried out across the CDS gene trees to investigate the degrees of ILS, gene flow and gene tree estimation error. Afterward, a regression analysis was used to test the relative contributions of each of these forms of uncertainty to the final phylogeny. Despite extensive topological discordance among gene trees, we found a fully supported species tree that agrees with the most of well-accepted relationships and establishes monophyly of the genus Allium. We presented clear evidence for substantial ILS across the phylogeny of Allium. Further, we identified two ancient hybridization events for the formation of the second evolutionary line and subg. Butomissa as well as several introgression events between recently diverged species. Our regression analysis revealed that gene tree inference error and gene flow were the two most dominant factors explaining for the overall gene tree variation, with the difficulty in disentangling the effects of ILS and gene tree estimation error due to a positive correlation between them. Based on our efforts to mitigate the methodological errors in reconstructing trees, we believed ILS and gene flow are two principal reasons for the oft-reported phylogenetic heterogeneity of Allium. This study presents a strongly-supported and well-resolved phylogenetic backbone for the sampled Allium species, and exemplifies how to untangle heterogeneity in phylogenetic signal and reconstruct the true evolutionary history of the target taxa.
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Affiliation(s)
- ZengZhu Zhang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Gang Liu
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Minjie Li
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, People's Republic of China.
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Liu J, Zhou SZ, Liu YL, Zhao BY, Yu D, Zhong MC, Jiang XD, Cui WH, Zhao JX, Qiu J, Liu LM, Guo ZH, Li HT, Tan DY, Hu JY, Li DZ. Genomes of Meniocus linifolius and Tetracme quadricornis reveal the ancestral karyotype and genomic features of core Brassicaceae. PLANT COMMUNICATIONS 2024:100878. [PMID: 38475995 DOI: 10.1016/j.xplc.2024.100878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 03/03/2024] [Accepted: 03/11/2024] [Indexed: 03/14/2024]
Abstract
Brassicaceae represents an important plant family from both a scientific and economic perspective. However, genomic features related to the early diversification of this family have not been fully characterized, especially upon the uplift of the Tibetan Plateau, which was followed by increasing aridity in the Asian interior, intensifying monsoons in Eastern Asia, and significantly fluctuating daily temperatures. Here, we reveal the genomic architecture that accompanied early Brassicaceae diversification by analyzing two high-quality chromosome-level genomes for Meniocus linifolius (Arabodae; clade D) and Tetracme quadricornis (Hesperodae; clade E), together with genomes representing all major Brassicaceae clades and the basal Aethionemeae. We reconstructed an ancestral core Brassicaceae karyotype (CBK) containing 9 pseudochromosomes with 65 conserved syntenic genomic blocks and identified 9702 conserved genes in Brassicaceae. We detected pervasive conflicting phylogenomic signals accompanied by widespread ancient hybridization events, which correlate well with the early divergence of core Brassicaceae. We identified a successive Brassicaceae-specific expansion of the class I TREHALOSE-6-PHOSPHATE SYNTHASE 1 (TPS1) gene family, which encodes enzymes with essential regulatory roles in flowering time and embryo development. The TPS1s were mainly randomly amplified, followed by expression divergence. Our results provide fresh insights into historical genomic features coupled with Brassicaceae evolution and offer a potential model for broad-scale studies of adaptive radiation under an ever-changing environment.
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Affiliation(s)
- Jie Liu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shi-Zhao Zhou
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yun-Long Liu
- Germplasm Bank of Wild Species & Yunnan Key Laboratory for Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Bin-Yan Zhao
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dongmei Yu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Mi-Cai Zhong
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Xiao-Dong Jiang
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Wei-Hua Cui
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Jiu-Xia Zhao
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Juan Qiu
- College of Life Sciences, Xinjiang Agricultural University, Ürümqi 830052, China
| | - Liang-Min Liu
- Germplasm Bank of Wild Species & Yunnan Key Laboratory for Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen-Hua Guo
- Germplasm Bank of Wild Species & Yunnan Key Laboratory for Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Hong-Tao Li
- Germplasm Bank of Wild Species & Yunnan Key Laboratory for Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Dun-Yan Tan
- College of Life Sciences, Xinjiang Agricultural University, Ürümqi 830052, China
| | - Jin-Yong Hu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
| | - De-Zhu Li
- Germplasm Bank of Wild Species & Yunnan Key Laboratory for Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
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Fu PC, Guo QQ, Chang D, Gao QB, Sun SS. Cryptic diversity and rampant hybridization in annual gentians on the Qinghai-Tibet Plateau revealed by population genomic analysis. PLANT DIVERSITY 2024; 46:194-205. [PMID: 38807911 PMCID: PMC11128845 DOI: 10.1016/j.pld.2023.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 10/24/2023] [Accepted: 10/25/2023] [Indexed: 05/30/2024]
Abstract
Understanding the evolutionary and ecological processes involved in population differentiation and speciation provides critical insights into biodiversity formation. In this study, we employed 29,865 single nucleotide polymorphisms (SNPs) and complete plastomes to examine genomic divergence and hybridization in Gentiana aristata, which is endemic to the Qinghai-Tibet Plateau (QTP) region. Genetic clustering revealed that G. aristata is characterized by geographic genetic structures with five clusters (West, East, Central, South and North). The West cluster has a specific morphological character (i.e., blue corolla) and higher values of FST compared to the remaining clusters, likely the result of the geological barrier formed by the Yangtze River. The West cluster diverged from the other clusters in the Early Pliocene; these remaining clusters diverged from one another in the Early Quaternary. Phylogenetic reconstructions based on SNPs and plastid data revealed substantial cyto-nuclear conflicts. Genetic clustering and D-statistics demonstrated rampant hybridization between the Central and North clusters, along the Bayankala Mountains, which form the geological barrier between the Central and North clusters. Species distribution modeling demonstrated the range of G. aristata expanded since the Last Interglacial period. Our findings provide genetic and morphological evidence of cryptic diversity in G. aristata, and identified rampant hybridization between genetic clusters along a geological barrier. These findings suggest that geological barriers and climatic fluctuations have an important role in triggering diversification as well as hybridization, indicating that cryptic diversity and hybridization are essential factors in biodiversity formation within the QTP region.
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Affiliation(s)
- Peng-Cheng Fu
- School of Life Science, Luoyang Normal University, Luoyang 471934, PR China
| | - Qiao-Qiao Guo
- School of Life Science, Luoyang Normal University, Luoyang 471934, PR China
| | - Di Chang
- School of Life Science, Luoyang Normal University, Luoyang 471934, PR China
| | - Qing-Bo Gao
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810001, PR China
| | - Shan-Shan Sun
- School of Life Science, Luoyang Normal University, Luoyang 471934, PR China
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Huang DQ, Ma XG, Sun H. Phylogenomic analyses and chromosome ploidy identification reveal multiple cryptic species in Allium sikkimense complex (Amaryllidaceae). FRONTIERS IN PLANT SCIENCE 2024; 14:1268546. [PMID: 38239226 PMCID: PMC10794568 DOI: 10.3389/fpls.2023.1268546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 12/06/2023] [Indexed: 01/22/2024]
Abstract
Polyploidization is a process that typically leads to instantaneous reproductive isolation and has, therefore, been considered as one of the major evolutionary forces in the species-rich Hengduan Mountains (HM), yet this topic remains poorly studied in the region. Allium sikkimense and its relatives (about eight species) compose a natural diploid-polyploid complex with the highest diversity in the HM and adjacent areas. A combination of nuclear ribosomal DNA (nrDNA), plastome, transcriptome, and ploidy identification through chromosome counting and flow cytometry is employed to reconstruct the phylogenetic relationships in this complex and to investigate the frequency and the evolutionary significance of polyploidy in the complex. The plastome failed to resolve the phylogenetic relationships of the different species in the A. sikkimense complex, and the phylogenetic tree based on nrDNA also has limited resolution. However, our study reveals a well-resolved phylogenetic framework for species in the A. sikkimense complex using more than 1,000 orthologous genes from the transcriptome data. Previously recognized morphospecies A. sikkimense are non-monophyletic and comprise at least two independently evolved lineages (i.e., cryptic species), each forming a clade with different diploid species in this complex. The embedded pattern of octoploid A. jichouense and tetraploid A. sp. nov. within different polyploid samples of A. sikkimense supports a possible scenario of budding speciation (via niche divergence). Furthermore, our results reveal that co-occurring species in the A. sikkimense complex usually have different ploidy levels, suggesting that polyploidy is an important process for reproductive isolation of sympatric Allium species. Phylogenetic network analyses suggested that the phylogenetic relationships of the A. sikkimense complex, allowing for reticulation events, always fit the dataset better than a simple bifurcating tree. In addition, the included or exserted filaments, which have long been used to delimit species, are highly unreliable taxonomically due to their extensive parallel and convergent evolution.
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Affiliation(s)
- De-Qing Huang
- College of Pharmacy, Guilin Medical University, Guilin, China
| | - Xiang-Guang Ma
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Hang Sun
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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Fu PC, Twyford AD, Hao YT, Zhang Y, Chen SL, Sun SS. Hybridization and divergent climatic preferences drive divergence of two allopatric Gentiana species on the Qinghai-Tibet Plateau. ANNALS OF BOTANY 2023; 132:1271-1288. [PMID: 37963010 PMCID: PMC10902892 DOI: 10.1093/aob/mcad179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 10/19/2023] [Accepted: 11/13/2023] [Indexed: 11/16/2023]
Abstract
BACKGROUND AND AIMS Exploring how species diverge is vital for understanding the drivers of speciation. Factors such as geographical separation and ecological selection, hybridization, polyploidization and shifts in mating system are all major mechanisms of plant speciation, but their contributions to divergence are rarely well understood. Here we test these mechanisms in two plant species, Gentiana lhassica and G. hoae, with the goal of understanding recent allopatric species divergence on the Qinghai-Tibet Plateau (QTP). METHODS We performed Bayesian clustering, phylogenetic analysis and estimates of hybridization using 561 302 nuclear genomic single nucleotide polymorphisms (SNPs). We performed redundancy analysis, and identified and annotated species-specific SNPs (ssSNPs) to explore the association between climatic preference and genetic divergence. We also estimated genome sizes using flow cytometry to test for overlooked polyploidy. KEY RESULTS Genomic evidence confirms that G. lhassica and G. hoae are closely related but distinct species, while genome size estimates show divergence occurred without polyploidy. Gentiana hoae has significantly higher average FIS values than G. lhassica. Population clustering based on genomic SNPs shows no signature of recent hybridization, but each species is characterized by a distinct history of hybridization with congeners that has shaped genome-wide variation. Gentiana lhassica has captured the chloroplast and experienced introgression with a divergent gentian species, while G. hoae has experienced recurrent hybridization with related taxa. Species distribution modelling suggested range overlap in the Last Interglacial Period, while redundancy analysis showed that precipitation and temperature are the major climatic differences explaining the separation of the species. The species differ by 2993 ssSNPs, with genome annotation showing missense variants in genes involved in stress resistance. CONCLUSIONS This study suggests that the distinctiveness of these species on the QTP is driven by a combination of hybridization, geographical isolation, mating system differences and evolution of divergent climatic preferences.
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Affiliation(s)
- Peng-Cheng Fu
- School of Life Science, Luoyang Normal University, 6 Jiqing Road, Luoyang 471934, P. R. China
| | - Alex D Twyford
- Institute of Ecology and Evolution, The University of Edinburgh, Edinburgh, EH9 3FL, UK
- Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh, EH3 5LR, UK
| | - Yu-Tong Hao
- School of Life Science, Luoyang Normal University, 6 Jiqing Road, Luoyang 471934, P. R. China
| | - Yue Zhang
- School of Life Science, Luoyang Normal University, 6 Jiqing Road, Luoyang 471934, P. R. China
| | - Shi-Long Chen
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, 810001 Xining, P. R. China
| | - Shan-Shan Sun
- School of Life Science, Luoyang Normal University, 6 Jiqing Road, Luoyang 471934, P. R. China
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Peng J, Ma X, Sun H. Ancient allopatry and ecological divergence act together to promote plant diversity in mountainous regions: evidence from comparative phylogeography of two genera in the Sino-Himalayan region. BMC PLANT BIOLOGY 2023; 23:572. [PMID: 37978437 PMCID: PMC10655281 DOI: 10.1186/s12870-023-04593-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 11/08/2023] [Indexed: 11/19/2023]
Abstract
BACKGROUND How geographical isolation and ecological divergence act together to promote plant diversity in mountainous regions remains largely unknown. In this study, we chose two genera comprising a small number of species distributed in the Sino-Himalayan region, Megacodon (Gentianaceae) and Beesia (Ranunculaceae), which both exhibit a fragmented distribution pattern and are found across a wide range of elevations. By summarizing their common patterns of speciation and/or divergence processes, we aim to understand how environmental changes accelerated lineage diversification in the Sino-Himalayan region through ancient allopatry and ecological divergence. RESULTS Using ddRAD-seq, chloroplast genome sequences, and specific molecular markers, we studied the phylogenetic relationships, population structure, and historical biogeography of Beesia and Megacodon. Both genera began to diverge from the late Miocene onwards, with ancient allopatry at lower elevations formed narrow-range species or relict populations. Mantel tests between genetic distance and climatic, elevational, or geographic distance revealed an isolation-by-distance pattern in Beesia and Megacodon stylophorus. Megacodon showed two clades occupying entirely different altitudinal ranges, whereas Beesia calthifolia exhibited a genetic divergence pattern along an elevation gradient. Furthermore, we conducted morphological measurements on Beesia calthifolia and found that different elevational groups had distinct leaf shapes. CONCLUSIONS The regional disjunctions of plant groups in the Sino-Himalayan region are drastic and closely related to several biogeographic boundaries. As a consequence of major geological and climate change, ecological divergence when different elevations are colonized often happens simultaneously within plant groups. Although habitat fragmentation and parapatric ecological divergence each spur speciation to different extents, a combined effect of these two factors is a common phenomenon in the Sino-Himalayan region.
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Affiliation(s)
- Junchu Peng
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Xiangguang Ma
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, China
| | - Hang Sun
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, China.
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Ju M, Yang J, Yue M, Zhao G. Speciation patterns of related species under the hybrid zone: A case study of three sclerophyllous oaks in the east Himalaya-Hengduan Mountains. Mol Ecol 2023; 32:4610-4626. [PMID: 37395683 DOI: 10.1111/mec.17060] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 05/28/2023] [Accepted: 06/15/2023] [Indexed: 07/04/2023]
Abstract
Speciation is often accompanied by frequent gene exchanges, which have been gradually recognized as a common phenomenon in nature. Although gene flow may influence different reproductive isolations, the specific mechanism of the process still requires more experimental evidence, especially in hybrid populations that have no significant differentiation and isolation. To address this challenge, this study aims to elucidate the underlying mechanisms of sympatry and parapatry in related species. Three sclerophyllous oaks (Quercus spinosa, Quercus aquifolioides and Quercus rehderiana), which are mainly distributed in the sympatry/parapatry of the East Himalaya-Hengduan Mountains and adjacent regions, were used to explore the population dynamics and evolutionary history. Based on 12,420 genome-wide single nucleotide polymorphism datasets, gene flow detection showed that the three species did not present any obvious genetic barriers. Evolutionary analysis indicated that the three species diverged during the Tertiary Period, and no migration events occurred in the early stages of species divergence. Combined with the data of 19 ecological factors, geological movements and climatic turbulence caused the rapid radiated differentiation of the three species during the Neocene, and similar selective pressures resulted in the same evolutionary pattern based on demographic history analysis. In addition, the predicted niche occupancy profiles and Generalized Dissimilarity Modelling revealed that the three species occupied distinct niches and had significant differences in ecological adaptation, which may explain the specific morphological characteristics of the different species. Therefore, we believe that the populations of the three related species underwent adaptive evolution in different habitats during the early stages of divergence. This study provides new experimental evidence of the formation patterns of parallel speciation.
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Affiliation(s)
- Miaomiao Ju
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, China
| | - Jia Yang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, China
| | - Ming Yue
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, China
- Xi'an Botanical Garden of Shaanxi Province (Institute of Botany of Shaanxi Province), Xi'an, China
| | - Guifang Zhao
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, China
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Stull GW, Pham KK, Soltis PS, Soltis DE. Deep reticulation: the long legacy of hybridization in vascular plant evolution. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 114:743-766. [PMID: 36775995 DOI: 10.1111/tpj.16142] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 02/02/2023] [Accepted: 02/07/2023] [Indexed: 05/27/2023]
Abstract
Hybridization has long been recognized as a fundamental evolutionary process in plants but, until recently, our understanding of its phylogenetic distribution and biological significance across deep evolutionary scales has been largely obscure. Over the past decade, genomic and phylogenomic datasets have revealed, perhaps not surprisingly, that hybridization, often associated with polyploidy, has been common throughout the evolutionary history of plants, particularly in various lineages of flowering plants. However, phylogenomic studies have also highlighted the challenges of disentangling signals of ancient hybridization from other sources of genomic conflict (in particular, incomplete lineage sorting). Here, we provide a critical review of ancient hybridization in vascular plants, outlining well-documented cases of ancient hybridization across plant phylogeny, as well as the challenges unique to documenting ancient versus recent hybridization. We provide a definition for ancient hybridization, which, to our knowledge, has not been explicitly attempted before. Further documenting the extent of deep reticulation in plants should remain an important research focus, especially because published examples likely represent the tip of the iceberg in terms of the total extent of ancient hybridization. However, future research should increasingly explore the macroevolutionary significance of this process, in terms of its impact on evolutionary trajectories (e.g. how does hybridization influence trait evolution or the generation of biodiversity over long time scales?), as well as how life history and ecological factors shape, or have shaped, the frequency of hybridization across geologic time and plant phylogeny. Finally, we consider the implications of ubiquitous ancient hybridization for how we conceptualize, analyze, and classify plant phylogeny. Networks, as opposed to bifurcating trees, represent more accurate representations of evolutionary history in many cases, although our ability to infer, visualize, and use networks for comparative analyses is highly limited. Developing improved methods for the generation, visualization, and use of networks represents a critical future direction for plant biology. Current classification systems also do not generally allow for the recognition of reticulate lineages, and our classifications themselves are largely based on evidence from the chloroplast genome. Updating plant classification to better reflect nuclear phylogenies, as well as considering whether and how to recognize hybridization in classification systems, will represent an important challenge for the plant systematics community.
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Affiliation(s)
- Gregory W Stull
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20013, USA
| | - Kasey K Pham
- Department of Biology, University of Florida, Gainesville, FL, 32611, USA
| | - Pamela S Soltis
- Florida Museum of Natural History, University of Florida, Gainesville, FL, 32611, USA
| | - Douglas E Soltis
- Department of Biology, University of Florida, Gainesville, FL, 32611, USA
- Florida Museum of Natural History, University of Florida, Gainesville, FL, 32611, USA
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Wei S, Zhang Q, Tang S, Liao W. Genetic and ecophysiological evidence that hybridization facilitated lineage diversification in yellow Camellia (Theaceae) species: a case study of natural hybridization between C. micrantha and C. flavida. BMC PLANT BIOLOGY 2023; 23:154. [PMID: 36944951 PMCID: PMC10031943 DOI: 10.1186/s12870-023-04164-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 03/11/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND Hybridization is generally considered an important creative evolutionary force, yet this evolutionary process is still poorly characterized in karst plants. In this study, we focus on natural hybridization in yellow Camellia species, a group of habitat specialists confined to karst/non-karst habitats in southwestern China. RESULTS Based on population genome data obtain from double digest restriction-site associated DNA (ddRAD) sequencing, we found evidence for natural hybridization and introgression between C. micrantha and C. flavida, and specifically confirmed their hybrid population, C. "ptilosperma". Ecophysiological results suggested that extreme hydraulic traits were fixed in C. "ptilosperma", these being consistent with its distinct ecological niche, which lies outside its parental ranges. CONCLUSION The identified hybridization event is expected to have played a role in generating novel variation during, in which the hybrid population displays different phenological characteristics and novel ecophysiological traits associated with the colonization of a new niche in limestone karst.
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Affiliation(s)
- Sujuan Wei
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Ministry of Education, Guangxi Normal University, Guilin, 541004, China
| | - Qiwei Zhang
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Ministry of Education, Guangxi Normal University, Guilin, 541004, China
| | - Shaoqing Tang
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Ministry of Education, Guangxi Normal University, Guilin, 541004, China.
| | - Wenbo Liao
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China.
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Ye LJ, Möller M, Luo YH, Zou JY, Zheng W, Liu J, Li DZ, Gao LM. Variation in gene expression along an elevation gradient of Rhododendron sanguineum var. haemaleum assessed in a comparative transcriptomic analysis. FRONTIERS IN PLANT SCIENCE 2023; 14:1133065. [PMID: 37025136 PMCID: PMC10070981 DOI: 10.3389/fpls.2023.1133065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 03/06/2023] [Indexed: 06/19/2023]
Abstract
Selection along environmental gradients may play a vital role in driving adaptive evolution. Nevertheless, genomic variation and genetic adaptation along environmental clines remains largely unknown in plants in alpine ecosystems. To close this knowledge gap, we assayed transcriptomic profiles of late flower bud and early leaf bud of Rhododendron sanguineum var. haemaleum from four different elevational belts between 3,000 m and 3,800 m in the Gaoligong Mountains. By comparing differences in gene expression of these samples, a gene co-expression network (WGCNA) was constructed to identify candidate genes related to elevation. We found that the overall gene expression patterns are organ-specific for the flower and leaf. Differentially expressed unigenes were identified in these organs. In flowers, these were mainly related to terpenoid metabolism (RsHMGR, RsTPS), while in leaves mainly related to anthocyanin biosynthesis (RsCHS, RsF3'5'H). Terpenoids are the main components of flower scent (fragrance) likely attracting insects for pollination. In response to fewer pollinators at higher elevation zone, it seems relatively less scent is produced in flower organs to reduce energy consumption. Secondary metabolites in leaves such as anthocyanins determine the plants' alternative adaptive strategy to extreme environments, such as selective pressures of insect herbivory from environmental changes and substrate competition in biosynthesis pathways at high elevations. Our findings indicated that the gene expression profiles generated from flower and leaf organs showed parallel expression shifts but with different functionality, suggesting the existence of flexibility in response strategies of plants exposed to heterogeneous environments across elevational gradients. The genes identified here are likely to be involved in the adaptation of the plants to these varying mountainous environments. This study thus contributes to our understanding of the molecular mechanisms of adaptation in response to environmental change.
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Affiliation(s)
- Lin-Jiang Ye
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
- Key Laboratory of Plant Resources and Biodiversity of Jiangxi Province, Jingdezhen University, Jingdezhen, Jiangxi, China
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Michael Möller
- Royal Botanic Garden Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Ya-Huang Luo
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
- Lijiang Forest Biodiversity National Observation and Research Station, Kunming Institute of Botany, Chinese Academy of Sciences, Lijiang, Yunnan, China
| | - Jia-Yun Zou
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Wei Zheng
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jie Liu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - De-Zhu Li
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
- Lijiang Forest Biodiversity National Observation and Research Station, Kunming Institute of Botany, Chinese Academy of Sciences, Lijiang, Yunnan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lian-Ming Gao
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
- Lijiang Forest Biodiversity National Observation and Research Station, Kunming Institute of Botany, Chinese Academy of Sciences, Lijiang, Yunnan, China
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Feder JL, Nosil P. Beyond dichotomies in species and speciation. Natl Sci Rev 2023; 9:nwad018. [PMID: 36778105 PMCID: PMC9905644 DOI: 10.1093/nsr/nwad018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2023] [Indexed: 01/19/2023] Open
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Birkeland S. To what degree does hybridization facilitate evolutionary radiations in mountain areas? Natl Sci Rev 2022; 9:nwac288. [PMID: 36694798 PMCID: PMC9855306 DOI: 10.1093/nsr/nwac288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
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O’Brien SJ, Luo SJ. Taxonomic species recognition should be consistent. Natl Sci Rev 2022; 9:nwad022. [PMID: 36788967 PMCID: PMC9923365 DOI: 10.1093/nsr/nwad022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2023] [Indexed: 01/26/2023] Open
Affiliation(s)
- Stephen J O’Brien
- Guy Harvey Oceanographic Center, Halmos College of Arts and Sciences, Nova Southeastern University, USA
| | - Shu-Jin Luo
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, China
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