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Rawat S, Jugran AK, Sharma H. Recent advancements in the physiological, genetic, and genomic research on Rhododendrons for trait improvement. 3 Biotech 2024; 14:164. [PMID: 38808301 PMCID: PMC11128433 DOI: 10.1007/s13205-024-04006-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 05/09/2024] [Indexed: 05/30/2024] Open
Abstract
High species diversity, hybridization potential, broad geographical dispersal range and ornamental characteristics (i.e., attractive size, shape, structure, flowers, and evergreen) have fetched a good international market for Rhododendron. However, most species are restricted to specific geographic areas due to their habitat specificity in acidic soil and cold climates, resulting many species being classified under threat categories of the IUCN. In this review, advances in research on Rhododendron for improvement to floral display quality and stress resistance have been described. The low genetic barrier among species has created opportunities for extensive hybridization and ploidy alteration for introducing quality and adaptive traits during the development of new varieties. Recent technological advances have supported investigations into the mechanism of flower development, as well as cold tolerance and pathogen resistance mechanisms in the Rhododendron. However, most of the species have limited adaptability to drought, line-tolerance, pathogen resistance, and high-temperature conditions and this resistance ability present in few species largely remains unexplored. Additionally, the available genetic diversity and genomic information on species, and possibilities for their application in molecular breeding have been summarized. Overall, genomic resource data are scarce in the majority of the members of this genus. Finally, various research gaps such as genetic mapping of quality traits, understanding the molecular mechanism of quality-related traits and genomic assortment in Rhododendron members have been discussed in the future perspective section. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-024-04006-6.
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Affiliation(s)
- Sandeep Rawat
- Sikkim Regional Centre, G. B. Pant National Institute of Himalayan Environment, Pangthang, Gangtok, Sikkim 737101 India
| | - Arun K. Jugran
- Garhwal Regional Centre, G. B. Pant National Institute of Himalayan Environment, Srinagar, Uttarakhand 246174 India
| | - Himanshu Sharma
- National Agri-Food Biotechnology Institute (NABI), Sector-81, SAS Nagar, Mohali, Punjab 140306 India
- Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan, Himachal Pradesh 173229 India
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2
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Ma Y, Mao X, Wang J, Zhang L, Jiang Y, Geng Y, Ma T, Cai L, Huang S, Hollingsworth P, Mao K, Kang M, Li Y, Yang W, Wu H, Chen Y, Davis CC, Shrestha N, Ree RH, Xi Z, Hu Q, Milne RI, Liu J. Pervasive hybridization during evolutionary radiation of Rhododendron subgenus Hymenanthes in mountains of southwest China. Natl Sci Rev 2022; 9:nwac276. [PMID: 36687562 PMCID: PMC9844246 DOI: 10.1093/nsr/nwac276] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/04/2022] Open
Abstract
Radiations are especially important for generating species biodiversity in mountainous ecosystems. The contribution of hybridization to such radiations has rarely been examined. Here, we use extensive genomic data to test whether hybridization was involved in evolutionary radiation within Rhododendron subgenus Hymenanthes, whose members show strong geographic isolation in the mountains of southwest China. We sequenced genomes for 143 species of this subgenus and 93 species of four other subgenera, and found that Hymenanthes was monophyletic and radiated during the late Oligocene to middle Miocene. Widespread hybridization events were inferred within and between the identified clades and subclades. This suggests that hybridization occurred both early and late during diversification of subgenus Hymenanthes, although the extent to which hybridization, speciation through mixing-isolation-mixing or hybrid speciation, accelerated the diversification needs further exploration. Cycles of isolation and contact in such and other montane ecosystems may have together promoted species radiation through hybridization between diverging populations and species. Similar radiation processes may apply to other montane floras in this region and elsewhere.
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Affiliation(s)
| | | | | | - Lei Zhang
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Yuanzhong Jiang
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Yuying Geng
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Tao Ma
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Liming Cai
- Department of Organismic and Evolutionary Biology and Harvard University Herbaria, Harvard University, Cambridge, MA 02138, USA
| | - Shuangquan Huang
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
| | | | - Kangshan Mao
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Minghui Kang
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Yiling Li
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Wenlu Yang
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Haolin Wu
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Yang Chen
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Charles C Davis
- Department of Organismic and Evolutionary Biology and Harvard University Herbaria, Harvard University, Cambridge, MA 02138, USA
| | - Nawal Shrestha
- State Key Laboratory of Grassland Agro-ecosystem, College of Ecology, Lanzhou University, Lanzhou 730000, China
| | - Richard H Ree
- Negaunee Integrative Research Center, Field Museum, Chicago, IL 60605, USA
| | - Zhenxiang Xi
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
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Mo ZQ, Fu CN, Zhu MS, Milne RI, Yang JB, Cai J, Qin HT, Zheng W, Hollingsworth PM, Li DZ, Gao LM. Resolution, conflict and rate shifts: insights from a densely sampled plastome phylogeny for Rhododendron (Ericaceae). ANNALS OF BOTANY 2022; 130:687-701. [PMID: 36087101 PMCID: PMC9670778 DOI: 10.1093/aob/mcac114] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 09/09/2022] [Indexed: 06/08/2023]
Abstract
BACKGROUND AND AIMS Rhododendron is a species-rich and taxonomically challenging genus due to recent adaptive radiation and frequent hybridization. A well-resolved phylogenetic tree would help to understand the diverse history of Rhododendron in the Himalaya-Hengduan Mountains where the genus is most diverse. METHODS We reconstructed the phylogeny based on plastid genomes with broad taxon sampling, covering 161 species representing all eight subgenera and all 12 sections, including ~45 % of the Rhododendron species native to the Himalaya-Hengduan Mountains. We compared this phylogeny with nuclear phylogenies to elucidate reticulate evolutionary events and clarify relationships at all levels within the genus. We also estimated the timing and diversification history of Rhododendron, especially the two species-rich subgenera Rhododendron and Hymenanthes that comprise >90 % of Rhododendron species in the Himalaya-Hengduan Mountains. KEY RESULTS The full plastid dataset produced a well-resolved and supported phylogeny of Rhododendron. We identified 13 clades that were almost always monophyletic across all published phylogenies. The conflicts between nuclear and plastid phylogenies suggested strongly that reticulation events may have occurred in the deep lineage history of the genus. Within Rhododendron, subgenus Therorhodion diverged first at 56 Mya, then a burst of diversification occurred from 23.8 to 17.6 Mya, generating ten lineages among the component 12 clades of core Rhododendron. Diversification in subgenus Rhododendron accelerated c. 16.6 Mya and then became fairly continuous. Conversely, Hymenanthes diversification was slow at first, then accelerated very rapidly around 5 Mya. In the Himalaya-Hengduan Mountains, subgenus Rhododendron contained one major clade adapted to high altitudes and another to low altitudes, whereas most clades in Hymenanthes contained both low- and high-altitude species, indicating greater ecological plasticity during its diversification. CONCLUSIONS The 13 clades proposed here may help to identify specific ancient hybridization events. This study will help to establish a stable and reliable taxonomic framework for Rhododendron, and provides insight into what drove its diversification and ecological adaption. Denser sampling of taxa, examining both organelle and nuclear genomes, is needed to better understand the divergence and diversification history of Rhododendron.
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Affiliation(s)
| | | | - Ming-Shu Zhu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Richard I Milne
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JH, UK
| | - Jun-Bo Yang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China
| | - Jie Cai
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China
| | - Han-Tao Qin
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Zheng
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
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Chang Y, Zhao S, Xiao H, Liu D, Huang Y, Wei Y, Ma Y. Unusual patterns of hybridization involving two alpine Salvia species: Absence of both F 1 and backcrossed hybrids. FRONTIERS IN PLANT SCIENCE 2022; 13:1010577. [PMID: 36330249 PMCID: PMC9623266 DOI: 10.3389/fpls.2022.1010577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
Natural hybridization plays an important role in speciation; however, we still know little about the mechanisms underlying the early stages of hybrid speciation. Hybrid zones are commonly dominated by F1s, or backcrosses, which impedes further speciation. In the present study, morphological traits and double digest restriction-site associated DNA sequencing (ddRAD-seq) data have been used to confirm natural hybridization between Salvia flava and S. castanea, the first case of identification of natural hybridization using combined phenotypic and molecular evidence in the East Asian clade of Salvia. We further examined several reproductive barriers in both pre-zygotic and post-zygotic reproductive stages to clarify the causes and consequences of the hybridization pattern. Our results revealed that reproductive isolation between the two species was strong despite the occurrence of hybridization. Interestingly, we found that most of the hybrids were likely to be F2s. This is a very unusual pattern of hybridization, and has rarely been reported before. The prevalence of geitonogamy within these self-compatible hybrids due to short distance foraging by pollinators might explain the origin of this unusual pattern. F2s can self-breed and develop further, therefore, we might be witnessing the early stages of hybrid speciation. Our study provides a new case for understanding the diversification of plants on the Qinghai-Tibet Plateau.
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Affiliation(s)
- Yuhang Chang
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shengxuan Zhao
- College of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Hanwen Xiao
- Eastern China Conservation Center for Wild Endangered Plant Resources, Shanghai Chenshan Botanical Garden, Shanghai, China
| | - Detuan Liu
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yanbo Huang
- Eastern China Conservation Center for Wild Endangered Plant Resources, Shanghai Chenshan Botanical Garden, Shanghai, China
| | - Yukun Wei
- Eastern China Conservation Center for Wild Endangered Plant Resources, Shanghai Chenshan Botanical Garden, Shanghai, China
- Shanghai Botanical Garden, Shanghai, China
| | - Yongpeng Ma
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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Wu S, Wang Y, Wang Z, Shrestha N, Liu J. Species divergence with gene flow and hybrid speciation on the Qinghai-Tibet Plateau. THE NEW PHYTOLOGIST 2022; 234:392-404. [PMID: 35020198 DOI: 10.1111/nph.17956] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 12/09/2021] [Indexed: 06/14/2023]
Abstract
The Qinghai-Tibet Plateau (QTP) sensu lato (sl), comprising the platform, the Himalaya and the Hengduan Mountains, is characterized by a large number of endemic plant species. This evolutionary cradle may have arisen from explosive species diversification because of geographic isolation. However, gene flow has been widely detected during the speciation processes of all groups examined, suggesting that natural selection may have also played an important role during species divergence in this region. In addition, natural hybrids have been recovered in almost all species-rich genera. This suggests that numerous species in this region are still 'on the speciation pathway to complete reproductive isolation (RI)'. Such hybrids could directly develop into new species through hybrid polyploidization and homoploid hybrid speciation (HHS). HHS may take place more easily than previously thought through alternate inheritance of alleles of parents at multiple RI loci. Therefore, isolation, selection and hybridization could together have promoted species diversification of numerous plant genera on the QTP sl. We emphasize the need for identification and functional analysis of alleles of major genes for speciation, and especially encourage investigations of parallel adaptive divergence causing RI across different lineages within similar but specific habitats in this region.
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Affiliation(s)
- Shengdan Wu
- State Key Laboratory of Grassland Agro-Ecosystems and College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Yi Wang
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Zefu Wang
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Nawal Shrestha
- State Key Laboratory of Grassland Agro-Ecosystems and College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Jianquan Liu
- State Key Laboratory of Grassland Agro-Ecosystems and College of Ecology, Lanzhou University, Lanzhou, 730000, China
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
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Liu R, Wang H, Yang JB, Corlett RT, Randle CP, Li DZ, Yu WB. Cryptic Species Diversification of the Pedicularis siphonantha Complex (Orobanchaceae) in the Mountains of Southwest China Since the Pliocene. FRONTIERS IN PLANT SCIENCE 2022; 13:811206. [PMID: 35401620 PMCID: PMC8987768 DOI: 10.3389/fpls.2022.811206] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
Morphological approaches often fail to delimit species in recently derived species complexes. This can be exacerbated in historical collections which may have lost key features in specimen preparation and preservation. Here, we examine the Pedicularis siphonantha complex, endemic to the Mountains of Southwest China. This complex is characterized by its red/purple/pink and long-tubular corolla, and twisted, beaked galea. However, herbarium specimens are often difficult to identify to species. Molecular approaches using nrITS or nuclear ribosomal internal transcribed spacer (nrITS) + plastid DNA (ptDNA) have been successfully used for species identification in Pedicularis. To resolve taxonomic confusion in the Pedicularis siphonantha complex, we reconstructed phylogenies of the complex using nrITS and four plastid DNA loci (matK, rbcL, trnH-psbA, and trnL-F). To recover as much of the phylogenetic history as possible, we sampled individuals at the population level. Topological incongruence between the nrITS and ptDNA datasets was recovered in clades including two widely distributed species, Pedicularis milliana and Pedicularis tenuituba. Based on morphological, geographical, and genetic evidence, we suggest that hybridization/introgression has occurred between P. milliana and Pedicularis sigmoidea/Pedicularis sp. 1 in the Yulong Snow Mountain of Lijiang, northwest Yunnan, and between P. tenuituba and Pedicularis leptosiphon in Ninglang, northwest Yunnan. After removing conflicting DNA regions in Pedicularis dolichosiphon (nrITS) and P. milliana (ptDNA), the concatenated nrITS and ptDNA phylogenies distinguish 11 species in the P. siphonantha complex, including two undescribed species, from the Jiaozi and Yulong Snow Mountains, respectively. Phylogeographical analyses indicate that the P. siponantha complex originated from south of the Hengduan Mountains, expanding north to the Himalayas and the Yunnan-Guizhou Plateau. Moreover, the uplift of the Qinghai-Tibet Plateau and climate oscillations may have driven further diversification in the complex.
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Affiliation(s)
- Rong Liu
- Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hong Wang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Jun-Bo Yang
- Plant Germplasm and Genomics Centre, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Richard T. Corlett
- Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, China
| | - Christopher P. Randle
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, United States
| | - De-Zhu Li
- Plant Germplasm and Genomics Centre, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Wen-Bin Yu
- Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, China
- Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Yezin, Myanmar
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Kuo WH, Liu SH, Chang CC, Hsieh CL, Li YH, Ito T, Won H, Kokubugata G, Chung KF. Plastome phylogenomics of Allaeanthus, Broussonetia and Malaisia (Dorstenieae, Moraceae) and the origin of B. × kazinoki. JOURNAL OF PLANT RESEARCH 2022; 135:203-220. [PMID: 35080694 DOI: 10.1007/s10265-022-01369-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Species of Broussonetia have been essential in the development of papermaking technology. In Japan and Korea, a hybrid between B. monoica and B. papyrifera (= B. × kazinoki) known as kōzo and daknamu is still the major source of raw materials for making traditional paper washi and hanji, respectively. Despite their cultural and practical significance, however, the origin and taxonomy of kōzo and daknamu remain controversial. Additionally, the long-held generic concept of Broussonetia s.l., which included Sect. Allaeanthus and Sect. Broussonetia, was challenged as phylogenetic analyses showed Malaisia is sister to the latter section. To re-examine the taxonomic proposition that recognizes Allaeanthus, Broussonetia, and Malaisia (i.e., Broussonetia alliance), plastome and nuclear ribosomal DNA (nrDNA) sequences of six species of the alliance were assembled. Characterized by the canonical quadripartite structure, genome alignments and contents of the six plastomes (160,121-162,594 bp) are highly conserved, except for the pseudogenization and/or loss of the rpl22 gene. Relationships of the Broussonetia alliance are identical between plastome and nrDNA trees, supporting the maintenance of Malaisia and the resurrection of Allaeanthus. The phylogenomic relationships also indicate that the monoecy in B. monoica is a derived state, possibly resulting from hybridization between the dioecious B. kaempferi (♀) and B. papyrifera (♂). Based on the hypervariable ndhF-rpl32 intergenic spacer selected by sliding window analysis, phylogeographic analysis indicates that B. monoica is the sole maternal parent of B. × kazinoki and that daknamu carries multiple haplotypes, while only one haplotype was detected in kōzo. Because hybridizations between B. monoica and B. papyrifera are unidirectional and have occurred rarely in nature, our data suggest that daknamu might have originated via deliberate hybrid breeding selected for making hanji in Korea. On the contrary, kōzo appears to have a single origin and the possibility of a Korean origin cannot be ruled out.
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Affiliation(s)
- Wen-Hsi Kuo
- Research Museum and Herbarium (HAST), Biodiversity Research Center, Academia Sinica, Taipei, 115201, Taiwan
- Department of Biology, Washington University, St. Louis, MO, USA
| | - Shih-Hui Liu
- Department of Biological Sciences, National Sun Yat- sen University, Kaohsiung, Taiwan
| | - Chiung-Chih Chang
- Research Museum and Herbarium (HAST), Biodiversity Research Center, Academia Sinica, Taipei, 115201, Taiwan
| | - Chia-Lun Hsieh
- Research Museum and Herbarium (HAST), Biodiversity Research Center, Academia Sinica, Taipei, 115201, Taiwan
| | - Yi-Hsuan Li
- Research Museum and Herbarium (HAST), Biodiversity Research Center, Academia Sinica, Taipei, 115201, Taiwan
| | - Takuro Ito
- The Center for Academic Resources and Archives/Botanical Gardens, Tohoku University, Sendai, Miyagi, Japan
| | - Hyosig Won
- Department of Biological Science and Institute of Natural Sciences, Daegu University, Gyungsan, Gyungbuk, South Korea
| | - Goro Kokubugata
- Department of Botany, National Museum of Nature and Science, Tsukuba, Ibaraki, Japan
| | - Kuo-Fang Chung
- Research Museum and Herbarium (HAST), Biodiversity Research Center, Academia Sinica, Taipei, 115201, Taiwan.
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Zheng W, Yan LJ, Burgess KS, Luo YH, Zou JY, Qin HT, Wang JH, Gao LM. Natural hybridization among three Rhododendron species (Ericaceae) revealed by morphological and genomic evidence. BMC PLANT BIOLOGY 2021; 21:529. [PMID: 34763662 PMCID: PMC8582147 DOI: 10.1186/s12870-021-03312-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 11/02/2021] [Indexed: 06/08/2023]
Abstract
BACKGROUND Natural hybridization can influence the adaptive response to selection and accelerate species diversification. Understanding the composition and structure of hybrid zones may elucidate patterns of hybridization processes that are important to the formation and maintenance of species, especially for taxa that have experienced rapidly adaptive radiation. Here, we used morphological traits, ddRAD-seq and plastid DNA sequence data to investigate the structure of a Rhododendron hybrid zone and uncover the hybridization patterns among three sympatric and closely related species. RESULTS Our results show that the hybrid zone is complex, where bi-directional hybridization takes place among the three sympatric parental species: R. spinuliferum, R. scabrifolium, and R. spiciferum. Hybrids between R. spinuliferum and R. spiciferum (R. ×duclouxii) comprise multiple hybrid classes and a high proportion of F1 generation hybrids, while a novel hybrid taxon between R. spinuliferum and R. scabrifolium dominated the F2 generation, but no backcross individuals were detected. The hybrid zone showed basically coincident patterns of population structure between genomic and morphological data. CONCLUSIONS Natural hybridization exists among the three Rhododendron species in the hybrid zone, although patterns of hybrid formation vary between hybrid taxa, which may result in different evolutionary outcomes. This study represents a unique opportunity to dissect the ecological and evolutionary mechanisms associated with adaptive radiation of Rhododendron species in a biodiversity hotspot.
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Affiliation(s)
- Wei Zheng
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, 10049, Beijing, China
| | - Li-Jun Yan
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, 10049, Beijing, China
- College of Vocational and Technical Education, Yunnan Normal University, 650092, Kunming, Yunnan, China
| | - Kevin S Burgess
- Department of Biology, Columbus State University, University System of Georgia, 31907-5645, Columbus, GA, USA
| | - Ya-Huang Luo
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
| | - Jia-Yun Zou
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, 10049, Beijing, China
| | - Han-Tao Qin
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, 10049, Beijing, China
| | - Ji-Hua Wang
- The Flower Research Institute, Yunnan Academy of Agricultural Sciences, 650205, Kunming, China.
| | - Lian-Ming Gao
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China.
- Lijiang Forest Biodiversity National Observation and Research Station, Kunming Institute of Botany, Chinese Academy of Sciences, 674100, Lijiang, Yunnan, China.
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Lyu R, He J, Luo Y, Lin L, Yao M, Cheng J, Xie L, Pei L, Yan S, Li L. Natural Hybrid Origin of the Controversial "Species" Clematis × pinnata (Ranunculaceae) Based on Multidisciplinary Evidence. FRONTIERS IN PLANT SCIENCE 2021; 12:745988. [PMID: 34712260 PMCID: PMC8545901 DOI: 10.3389/fpls.2021.745988] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 09/22/2021] [Indexed: 05/23/2023]
Abstract
Interspecific hybridization is common and has often been viewed as a driving force of plant diversity. However, it raises taxonomic problems and thus impacts biodiversity estimation and biological conservation. Although previous molecular phylogenetic studies suggested that interspecific hybridization may be rather common in Clematis, and artificial hybridization has been widely applied to produce new Clematis cultivars for nearly two centuries, the issue of natural hybridization of Clematis has never been addressed in detail. In this study, we tested the hybrid origin of a mesophytic and cold-adapted vine species, Clematis pinnata, which is a rare and taxonomically controversial taxon endemic to northern China. Using field investigations, flow cytometry (FCM), phylogenomic analysis, morphological statistics, and niche modeling, we tested hybrid origin and species status of C. pinnata. The FCM results showed that all the tested species were homoploid (2n = 16). Phylonet and HyDe analyses based on transcriptome data showed the hybrid origins of C. × pinnata from either C. brevicaudata × C. heracleifolia or C. brevicaudata × C. tubulosa. The plastome phylogeny depicted that C. × pinnata in different sampling sites originated by different hybridization events. Morphological analysis showed intermediacy of C. × pinnata between its putative parental species in many qualitative and quantitative characters. Niche modeling results suggested that C. × pinnata had not been adapted to a novel ecological niche independent of its putative parents. These findings demonstrated that plants of C. × pinnata did not formed a self-evolved clade and should not be treated as a species. The present study also suggests that interspecific hybridization is a common mechanism in Clematis to generate diversity and variation, and it may play an important role in the evolution and diversification of this genus. Our study implies that morphological diversity caused by natural hybridization may overstate the real species diversity in Clematis.
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Affiliation(s)
- Rudan Lyu
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Jian He
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Yike Luo
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Lele Lin
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Min Yao
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Jin Cheng
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
| | - Lei Xie
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Linying Pei
- Beijing Engineering Research Center for Landscape Plant, Beijing Forestry University Forest Science Co. Ltd., Beijing, China
| | - Shuangxi Yan
- College of Landscape Architecture and Art, Henan Agricultural University, Zhengzhou, China
| | - Liangqian Li
- Institute of Botany, The Chinese Academy of Sciences, Beijing, China
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10
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Khan G, Nolzen J, Schepker H, Albach DC. Incongruent phylogenies and their implications for the study of diversification, taxonomy, and genome size evolution of Rhododendron. AMERICAN JOURNAL OF BOTANY 2021; 108:1957-1981. [PMID: 34668570 DOI: 10.1002/ajb2.1747] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 08/06/2021] [Accepted: 08/06/2021] [Indexed: 05/20/2023]
Abstract
PREMISE Classification of taxa depends on the quality of inferred phylogenies. Rhododendron, a highly species-rich genus (>1156 species) of woody plants, has a highly debated infrageneric classification, due to its huge diversity, homoplasy in key characters, and incongruence among data sets. We provide a broad coverage of representative species to resolve Rhododendron infrageneric phylogeny and highlight the areas of incongruence. We further investigate the effect of polyploidy and genome size evolution on diversification of Rhododendron. METHODS We generated two plastid and two nuclear loci for 260 Rhododendron species. We analyzed the loci separately as well as concatenated, utilizing both likelihood and Bayesian methods. We tested incongruence both among the data sets and with previous studies. We estimated genome sizes for 125 species through flow cytometry. RESULTS Our results suggest stronger support for larger subgenera; however, the smaller subgenera pose several problems; for example, R. tomentosum (former genus Ledum) occupies incongruent positions based on different DNA regions. The main shift to higher diversification in the genus occurs in the Himalayan/Southeast Asian clade of R. subg. Hymenanthes. We found that polyploidy occurs in almost all subgenera but most frequently within R. subg. Rhododendron sections Rhododendron and Schistanthe. CONCLUSIONS We endorse the recognition of five major clades at the subgeneric level, but a number of species cannot be confidently assigned to these clades due to incongruency. With regard to genome size evolution, results support previous reports that genome sizes of tropical plants are lower than those of colder and temperate regions and that genome downsizing promotes diversification.
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Affiliation(s)
- Gulzar Khan
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Carl von Ossietzky Strasse 9-11, Oldenburg, 26111, Germany
| | - Jennifer Nolzen
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Carl von Ossietzky Strasse 9-11, Oldenburg, 26111, Germany
| | - Hartwig Schepker
- Stiftung Bremer Rhododendronpark, Deliusweg 40, Bremen, 28359, Germany
| | - Dirk C Albach
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Carl von Ossietzky Strasse 9-11, Oldenburg, 26111, Germany
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11
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Fu CN, Mo ZQ, Yang JB, Cai J, Ye LJ, Zou JY, Qin HT, Zheng W, Hollingsworth PM, Li DZ, Gao LM. Testing genome skimming for species discrimination in the large and taxonomically difficult genus Rhododendron. Mol Ecol Resour 2021; 22:404-414. [PMID: 34310851 DOI: 10.1111/1755-0998.13479] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 06/22/2021] [Accepted: 07/05/2021] [Indexed: 12/01/2022]
Abstract
Standard plant DNA barcodes based on 2-3 plastid regions, and nrDNA ITS show variable levels of resolution, and fail to discriminate among species in many plant groups. Genome skimming to recover complete plastid genome sequences and nrDNA arrays has been proposed as a solution to address these resolution limitations. However, few studies have empirically tested what gains are achieved in practice. Of particular interest is whether adding substantially more plastid and nrDNA characters will lead to an increase in discriminatory power, or whether the resolution limitations of standard plant barcodes are fundamentally due to plastid genomes and nrDNA not tracking species boundaries. To address this, we used genome skimming to recover near-complete plastid genomes and nuclear ribosomal DNA from Rhododendron species and compared discrimination success with standard plant barcodes. We sampled 218 individuals representing 145 species of this species-rich and taxonomically difficult genus, focusing on the global biodiversity hotspots of the Himalaya-Hengduan Mountains. Only 33% of species were distinguished using ITS+matK+rbcL+trnH-psbA. In contrast, 55% of species were distinguished using plastid genome and nrDNA sequences. The vast majority of this increase is due to the additional plastid characters. Thus, despite previous studies showing an asymptote in discrimination success beyond 3-4 plastid regions, these results show that a demonstrable increase in discriminatory power is possible with extensive plastid genome data. However, despite these gains, many species remain unresolved, and these results also reinforce the need to access multiple unlinked nuclear loci to obtain transformative gains in species discrimination in plants.
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Affiliation(s)
- Chao-Nan Fu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Zhi-Qiong Mo
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,University of the Chinese Academy of Sciences, Beijing, China
| | - Jun-Bo Yang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Jie Cai
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - 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.,University of the Chinese Academy of Sciences, Beijing, 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.,University of the Chinese Academy of Sciences, Beijing, China
| | - Han-Tao Qin
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,University of the Chinese Academy of Sciences, Beijing, 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 the Chinese Academy of Sciences, Beijing, China
| | | | - De-Zhu Li
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,University of the 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 Ecosystem National Observation and Research Station, Kunming Institute of Botany, Chinese Academy of Sciences, Lijiang, Yunnan, China
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12
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Lu Z, Sun Y, Li Y, Yang Y, Wang G, Liu J. Species delimitation and hybridization history of a hazel species complex. ANNALS OF BOTANY 2021; 127:875-886. [PMID: 33564860 PMCID: PMC8225278 DOI: 10.1093/aob/mcab015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/03/2021] [Indexed: 06/01/2023]
Abstract
BACKGROUND AND AIMS Hybridization increases species adaptation and biodiversity but also obscures species boundaries. In this study, species delimitation and hybridization history were examined within one Chinese hazel species complex (Corylus chinensis-Corylus fargesii). Two species including four varieties have already been described for this complex, with overlapping distributions. METHODS A total of 322 trees from 44 populations of these four varieties across their ranges were sampled for morphological and molecular analyses. Climatic datasets based on 108 geographical locations were used to evaluate their niche differentiations. Flowering phenology was also observed for two co-occurring species or varieties. KEY RESULTS Four statistically different phenotypic clusters were revealed, but these clusters were highly inconsistent with the traditional taxonomic groups. All the clusters showed statistically distinct niches, with complete or partial geographical isolation. Only two clusters displayed a distributional overlap, but they had distinct flowering phenologies at the site where they co-occurred. Population-level evidence based on the genotypes of ten simple sequence repeat loci supported four phenotypic clusters. In addition, one cluster was shown to have an admixed genetic composition derived from the other three clusters through repeated historical hybridizations. CONCLUSIONS Based on our new evidence, it is better to treat the four clusters identified here as four independent species. One of them was shown to have an admixed genetic composition derived from the other three through repeated historical hybridizations. This study highlights the importance of applying integrative and statistical methods to infer species delimitations and hybridization history. Such a protocol should be adopted widely for future taxonomic studies.
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Affiliation(s)
- Zhiqiang Lu
- State Key Laboratory of Grassland Agro-Ecosystem, Institute of Innovation Ecology & School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - Yongshuai Sun
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - Ying Li
- State Key Laboratory of Grassland Agro-Ecosystem, Institute of Innovation Ecology & School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Yongzhi Yang
- State Key Laboratory of Grassland Agro-Ecosystem, Institute of Innovation Ecology & School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Gaini Wang
- State Key Laboratory of Grassland Agro-Ecosystem, Institute of Innovation Ecology & School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Jianquan Liu
- State Key Laboratory of Grassland Agro-Ecosystem, Institute of Innovation Ecology & School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
- Key Laboratory for Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
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13
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Duan SG, Hong K, Tang M, Tang J, Liu LX, Gao GF, Shen ZJ, Zhang XM, Yi Y. Untargeted metabolite profiling of petal blight in field-grown Rhododendron agastum using GC-TOF-MS and UHPLC-QTOF-MS/MS. PHYTOCHEMISTRY 2021; 184:112655. [PMID: 33540237 DOI: 10.1016/j.phytochem.2021.112655] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/30/2020] [Accepted: 01/03/2021] [Indexed: 06/12/2023]
Abstract
Petal blight caused by fungi is among the most destructive diseases of Rhododendron, especially Rhododendron agastum. Nonetheless, the metabolite changes that occur during petal blight are unknown. We used untargeted gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) and ultra-high performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) to compare the metabolite profiles of healthy and petal blight R. agastum flowers. Using GC-TOF-MS, 571 peaks were extracted, of which 189 metabolites were tentatively identified. On the other hand, 364 and 277 metabolites were tentatively identified in the positive and negative ionization modes of the UHPLC-QTOF-MS/MS, respectively. Principal component analysis (PCA) and orthogonal projections to latent structures-discriminant analysis (OPLS-DA) were able to clearly discriminate between healthy and petal blight flowers. Differentially abundant metabolites were primarily enriched in the biosynthesis of specialized metabolites. 17 accumulated specialized metabolites in petal blight flowers have been reported to have antifungal activity, and literature indicates that 9 of them are unique to plants. 3 metabolites (chlorogenic acid, medicarpin, and apigenin) are reportedly involved in resistance to blight caused by pathogens. We therefore speculate that the accumulation of chlorogenic acid, medicarpin, and apigenin may be involved in the resistance to petal blight. Our results suggest that these metabolites may be used as candidate biocontrol agents for the control fungal petal blight in Rhododendron.
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Affiliation(s)
- Sheng-Guang Duan
- Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, Key Laboratory of Plant Physiology and Development Regulation, School of Life Science, Guizhou Normal University, Guiyang, Guizhou, 550001, China
| | - Kun Hong
- Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, Key Laboratory of Plant Physiology and Development Regulation, School of Life Science, Guizhou Normal University, Guiyang, Guizhou, 550001, China
| | - Ming Tang
- Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, Key Laboratory of Plant Physiology and Development Regulation, School of Life Science, Guizhou Normal University, Guiyang, Guizhou, 550001, China
| | - Jing Tang
- Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, Key Laboratory of Plant Physiology and Development Regulation, School of Life Science, Guizhou Normal University, Guiyang, Guizhou, 550001, China
| | - Lun-Xian Liu
- Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, Key Laboratory of Plant Physiology and Development Regulation, School of Life Science, Guizhou Normal University, Guiyang, Guizhou, 550001, China
| | - Gui-Feng Gao
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Zhi-Jun Shen
- Key Laboratory for Subtropical Wetland Ecosystem Research of Ministry of Education, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361005, China
| | - Xi-Min Zhang
- Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, Key Laboratory of Plant Physiology and Development Regulation, School of Life Science, Guizhou Normal University, Guiyang, Guizhou, 550001, China.
| | - Yin Yi
- Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, Key Laboratory of Plant Physiology and Development Regulation, School of Life Science, Guizhou Normal University, Guiyang, Guizhou, 550001, China.
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14
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Liao R, Sun W, Ma Y. Natural hybridization between two butterfly bushes in Tibet: dominance of F 1 hybrids promotes strong reproductive isolation. BMC PLANT BIOLOGY 2021; 21:133. [PMID: 33691631 PMCID: PMC7945306 DOI: 10.1186/s12870-021-02909-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 02/28/2021] [Indexed: 05/30/2023]
Abstract
BACKGROUND It has been recognized that a certain amount of habitat disturbance is a facilitating factor for the occurrence of natural hybridization, yet to date we are unaware of any studies exploring hybridization and reproductive barriers in those plants preferentially occupying disturbed habitats. Buddleja plants (also called butterfly bush) generally do grow in disturbed habitats, and several species with hybrid origin have been proposed, based solely on morphological evidence. RESULTS In the present study, we test the hypothesis that B. × wardii is of natural hybridization origin in two sympatric populations of three taxa including B. × wardii and its parents (B. alternifolia and B. crispa) plus 4 referenced parental populations, using four nuclear genes and three chloroplast intergenic spacers, as well as with 10 morphological characters. Our results suggest that at both sites B. × wardii is likely to be a hybrid between B. alternifolia and B. crispa, and moreover, we confirm that most of the hybrids examined are F1s. That these plants are F1s is further supported by morphology, as no transgressive characters were detected. B. crispa was found to be the maternal parent in the Bahe (BH) population, from cpDNA evidence. However, in the Taji (TJ) population, the direction of hybridization was difficult to establish due to the shared cpDNA haplotypes between B. alternifolia and B. crispa, however we still predicted a similar unidirectional hybridization pattern due to results from cross-specific pollination treatments which supported the "SI × SC rule". CONCLUSIONS The presence of mainly F1 hybrids can successfully impede gene flow and thus maintain species boundaries in parental species in a typical distribution of Buddleja, i.e. in disturbed habitats.
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Affiliation(s)
- Rongli Liao
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations/ Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Weibang Sun
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations/ Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China.
| | - Yongpeng Ma
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations/ Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China.
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15
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Mao X, Wang J, Shrestha N, Ma Y, Liu J. Species Identification in the Rhododendron vernicosum- R. decorum Species Complex (Ericaceae). FRONTIERS IN PLANT SCIENCE 2021; 12:608964. [PMID: 33584768 PMCID: PMC7876077 DOI: 10.3389/fpls.2021.608964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 01/06/2021] [Indexed: 06/12/2023]
Abstract
Delimitating species boundaries is the primary aim of biological classification and could be critical for evaluating the evolving process of species and conserving biodiversity. Rhododendron is an iconic group with an extraordinary diversity in southwest China. However, it remains unknown whether the recorded species therein comprise independently evolving lineages or artificially delimitated morphological entities. In this study, we carried out species delimitation of four Rhododendron species in the R. vernicosum-R. decorum species complex based on morphological analyses and population genetic data from nuclear simple sequence repeats (SSR) markers. We randomly selected a total of 105 specimens of different individuals identified as four species across their distributional ranges to examine the statistically distinct phenotypic clusters based on 19 morphological traits. Similarly, we genotyped 55 individuals of four species from 21 populations using 15 SSR markers. The morphological analyses sorted R. decorum and the other three species into two different phenotypic clusters. The genetic clusters were consistent with the morphological clusters. However, we also recovered the third genetic cluster, comprising six R. vernicosum populations and containing the admixed genetic compositions of the other two distinct genetic clusters. This hybrid group was morphologically similar to the typical R. vernicosum (including the samples from its type specimen locality and both R. verruciferum and R. gonggashanense) but with more genetic ancestry from R. decorum. Based on our findings, we identify two distinct species and one putative hybrid group due to introgression in the R. vernicosum-R. decorum species complex. We propose to merge R. verruciferum and R. gonggashanense into R. vernicosum based on genetic compositions and our morphological analyses. The hybrid group inferred from our findings, however, needs further investigations.
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Affiliation(s)
- Xingxing Mao
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education and State Key Lab of Hydraulics and Mountain River Engineering, College of Life Sciences, Sichuan University, Chengdu, China
| | - Ji Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education and State Key Lab of Hydraulics and Mountain River Engineering, College of Life Sciences, Sichuan University, Chengdu, China
| | - Nawal Shrestha
- State Key Laboratory of Grassland Agro-Ecosystem, Institute of Innovation Ecology, Lanzhou University, Lanzhou, China
| | - Yazhen Ma
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education and State Key Lab of Hydraulics and Mountain River Engineering, College of Life Sciences, Sichuan University, Chengdu, China
| | - Jianquan Liu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education and State Key Lab of Hydraulics and Mountain River Engineering, College of Life Sciences, Sichuan University, Chengdu, China
- State Key Laboratory of Grassland Agro-Ecosystem, Institute of Innovation Ecology, Lanzhou University, Lanzhou, China
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16
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Lu Z, Sun Y. Rhamnella intermedia (Rhamnaceae), a new evergreen species from southwest Guangxi. PHYTOKEYS 2020; 159:115-126. [PMID: 32973391 PMCID: PMC7486312 DOI: 10.3897/phytokeys.159.53177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 07/28/2020] [Indexed: 06/11/2023]
Abstract
Rhamnella intermedia, a new evergreen species from southwest Guangxi, is described and illustrated in this study. This species is similar to R. brachycarpa by the size and ratio of length to width of dried fruit and seeds, by which it differs from R. rubrinervis and R. tonkinensis. However, it differs from R. brachycarpa by rarely mucronate seed apices, larger ratio of length to width of leaves, leaf apices acuminate to long acuminate, shorter leaf petioles, and longer fruiting pedicels. Principal component analysis based on phenotypic traits further recognised three separated groups. Rhamnella rubrinervis and R. tonkinensis were clustered into one group; the other two groups represented R. brachycarpa and two Guangxi populations, respectively. Furthermore, phylogenetic analysis of nuclear ITS sequence variations highly supported that the two Guangxi populations represented an independent evolutionary lineage and were closest to R. rubrinervis. Four fixed nucleotide sites were found and were different from R. rubrinervis. However, besides the differentiated traits in seeds and fruit, densely pilose young branches also separated them from R. rubrinervis. In addition, during our field investigations, none of the three closely related species were found at locations where this new species was distributed. Therefore, this new species, based on the two Guangxi populations, is named R. intermedia. The key to four closely related species is also presented.
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Affiliation(s)
- Zhiqiang Lu
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, Yunnan, ChinaChinese Academy of SciencesMenglaChina
- Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla 666303, Yunnan, ChinaChinese Academy of SciencesMenglaChina
| | - Yongshuai Sun
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, Yunnan, ChinaChinese Academy of SciencesMenglaChina
- Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla 666303, Yunnan, ChinaChinese Academy of SciencesMenglaChina
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Zhang X, Qin H, Xie W, Ma Y, Sun W. Comparative population genetic analyses suggest hybrid origin of R hododendron pubicostatum, an endangered plant species with extremely small populations endemic to Yunnan, China. PLANT DIVERSITY 2020; 42:312-318. [PMID: 33094202 PMCID: PMC7567756 DOI: 10.1016/j.pld.2020.06.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 05/08/2023]
Abstract
Gene flow between sympatric congeneric plants is thought to be very common and may pose serious threats to endangered species. In the present study, we evaluate the genetic diversity and divergence of three sympatric Rhododendron species in Jiaozi Mountain using newly developed microsatellites through the Illumina MiSeq sequencing approach. Genetic diversity of all three Rhododendron species studied was moderate in comparison to genetic parameters previously reported from species of this genus. Interestingly, genetic structure analysis of the three species identified a possible hybrid origin of the threatened Rh. pubicostatum. This sympatry should be considered a unimodal hybrid zone, since R h. pubicostatum is predominant here. Unimodal hybrid zones are uncommon in Rhododendron, despite the fact that hybridization frequently occurs in the genus. Issues pertaining to the conservation of R h. pubicostatum resulting from admixture of genetic material from its parental species are discussed.
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Affiliation(s)
- Xuemei Zhang
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, 650201, Yunnan, China
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, 650201, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Hantao Qin
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, 650201, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Weijia Xie
- Flower Research Institute, Yunnan Academy of Agriculture Sciences, Kunming, 650201, China
| | - Yongpeng Ma
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, 650201, Yunnan, China
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, 650201, China
| | - Weibang Sun
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, 650201, Yunnan, China
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, 650201, China
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Qian CY, Quan WX, Xiang ZM, Li CC. Characterization of Volatile Compounds in Four Different Rhododendron Flowers by GC×GC-QTOFMS. Molecules 2019; 24:molecules24183327. [PMID: 31547401 PMCID: PMC6767277 DOI: 10.3390/molecules24183327] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 01/13/2023] Open
Abstract
Volatile compounds in flowers of Rhododendron delavayi, R. agastum, R. annae, and R. irroratum were analyzed using comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC) coupled with high-resolution quadrupole time-of-flight mass spectrometry (QTOFMS). A significantly increased number of compounds was separated by GC×GC compared to conventional one-dimensional GC (1DGC), allowing more comprehensive understanding of the volatile composition of Rhododendron flowers. In total, 129 volatile compounds were detected and quantified. Among them, hexanal, limonene, benzeneacetaldehyde, 2-nonen-1-ol, phenylethyl alcohol, citronellal, isopulegol, 3,5-dimethoxytoluene, and pyridine are the main compounds with different content levels in all flower samples. 1,2,3-trimethoxy-5-methyl-benzene exhibits significantly higher content in R. irroratum compared to in the other three species, while isopulegol is only found in R. irroratum and R. agastum.
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Affiliation(s)
- Chen-Yu Qian
- Guangdong Provincial Key Laboratory of Emergency Test for Dangerous Chemicals/Guangdong Engineering and Technology Research Center for Ambient Mass Spectrometry, Guangdong Institute of Analysis, Guangzhou 510070, China.
- Guizhou Provincial Key Laboratory of Mountainous Environmental Protection, Guizhou Normal University, Guiyang 550001, China.
| | - Wen-Xuan Quan
- Guizhou Provincial Key Laboratory of Mountainous Environmental Protection, Guizhou Normal University, Guiyang 550001, China.
| | - Zhang-Min Xiang
- Guangdong Provincial Key Laboratory of Emergency Test for Dangerous Chemicals/Guangdong Engineering and Technology Research Center for Ambient Mass Spectrometry, Guangdong Institute of Analysis, Guangzhou 510070, China.
| | - Chao-Chan Li
- Guizhou Provincial Key Laboratory of Mountainous Environmental Protection, Guizhou Normal University, Guiyang 550001, China.
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Yang R, Folk R, Zhang N, Gong X. Homoploid hybridization of plants in the Hengduan mountains region. Ecol Evol 2019; 9:8399-8410. [PMID: 31380098 PMCID: PMC6662326 DOI: 10.1002/ece3.5393] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 04/24/2019] [Accepted: 05/30/2019] [Indexed: 12/24/2022] Open
Abstract
The Hengduan Mountains Region (HMR) is a major global biodiversity hotspot. Complex tectonic and historical climatic conditions created opportunities for natural interspecific hybridization. Likewise, anthropogenic disturbance potentially raises the frequency of hybridization. Among species studies to date, the frequency of homoploid hybridization appears in the HMR. Of nine taxa in which natural hybridization has been detected, three groups are involved in homoploid hybrid speciation, and species pairs from the remaining six genera suggest that continuous gene flow occurs in hybrid zones. Reproductive isolation may greatly affect the dynamic and architecture of hybrid zones in the HMR. Asymmetrical hybridization and introgression can primarily be attributed to both prezygotic and postzygotic barriers. The frequent observation of such asymmetry may imply that reproductive barrier contributes to maintaining species boundaries in the alpine region. Ecological isolations with environmental disturbance may promote breeding barriers between parental species and hybrids. Hybrid zones may be an important phase for homoploid hybrid speciation. Hybrid zones potentially provided abundant genetic resources for the diversification of the HMR flora. The ecological and molecular mechanisms of control and mediation for natural hybridization will help biologists to understand the formation of biodiversity in the HMR. More researches from ecological and molecular aspects were required in future studies.
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Affiliation(s)
- Rui Yang
- Key Laboratory for Plant Diversity and Biogeography of East AsiaKunming Institute of Botany, Chinese Academy of SciencesKunmingChina
- Key Laboratory of Economic Plants and BiotechnologyKunming Institute of Botany, Chinese Academy of SciencesKunmingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Ryan Folk
- Florida Museum of Natural HistoryUniversity of FloridaGainesvilleFloridaUSA
| | - Ningning Zhang
- Key Laboratory for Plant Diversity and Biogeography of East AsiaKunming Institute of Botany, Chinese Academy of SciencesKunmingChina
- Key Laboratory of Economic Plants and BiotechnologyKunming Institute of Botany, Chinese Academy of SciencesKunmingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Xun Gong
- Key Laboratory for Plant Diversity and Biogeography of East AsiaKunming Institute of Botany, Chinese Academy of SciencesKunmingChina
- Key Laboratory of Economic Plants and BiotechnologyKunming Institute of Botany, Chinese Academy of SciencesKunmingChina
- Yunnan Key Laboratory for Wild Plant ResourcesKunmingChina
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Yan LJ, Burgess KS, Zheng W, Tao ZB, Li DZ, Gao LM. Incomplete reproductive isolation between Rhododendron taxa enables hybrid formation and persistence. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2019; 61:433-448. [PMID: 30192058 DOI: 10.1111/jipb.12718] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Accepted: 09/06/2018] [Indexed: 06/08/2023]
Abstract
The evolutionary consequences of hybridization ultimately depend on the magnitude of reproductive isolation between hybrids and their parents. We evaluated the relative contributions of pre- and post-zygotic barriers to reproduction for hybrid formation, hybrid persistence and potential for reproductive isolation of hybrids formed between two Rhododendron species, R. spiciferum and R. spinuliferum. Our study established that incomplete reproductive isolation promotes hybrid formation and persistence and delays hybrid speciation. All pre-zygotic barriers to reproduction leading to hybrid formation are incomplete: parental species have overlapping flowering; they share the same pollinators; reciprocal assessments of pollen tube germination and growth do not differ among parents. The absence of post-zygotic barriers between parental taxa indicates that the persistence of hybrids is likely. Reproductive isolation was incomplete between hybrids and parents in all cases studied, although asymmetric differences in reproductive fitness were prevalent and possibly explain the genetic structure of natural hybrid swarms where hybridization is known to be bidirectional but asymmetric. Introgression, rather than speciation, is a probable evolutionary outcome of hybridization between the two Rhododendron taxa. Our study provides insights into understanding the evolutionary implications of natural hybridization in woody plants.
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Affiliation(s)
- Li-Jun Yan
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
- Germplasm Bank of Wild Species, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming 650201, China
- College of Vocational and Technical Education, Yunnan Normal University, Kunming 650092, China
| | - Kevin S Burgess
- Department of Biology, College of Letters & Sciences, Columbus State University, University System of Georgia, 31907-5645 Columbus, GA, USA
| | - Wei Zheng
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming 650201, China
| | - Zhi-Bin Tao
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming 650201, China
| | - De-Zhu Li
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
- Germplasm Bank of Wild Species, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming 650201, China
| | - Lian-Ming Gao
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
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Zhang N, Ma Y, Folk RA, Yu J, Pan Y, Gong X. Maintenance of species boundaries in three sympatric Ligularia (Senecioneae, Asteraceae) species. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2018; 60:986-999. [PMID: 29877612 DOI: 10.1111/jipb.12674] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 05/31/2018] [Indexed: 06/08/2023]
Abstract
The key process in speciation concerns the formation and maintenance of reproductive isolating barriers between diverging lineages. Although species boundaries are frequently investigated between two species across many taxa, reproductive isolating barriers among multiple species (>2) that would represent the most common phenomenon in nature, remain to be clarified. Here, we use double digest restriction-site associated DNA (ddRAD) sequencing to examine patterns of hybridization at a sympatric site where three Ligularia species grow together and verify whether those patterns contribute to the maintenance of boundaries among species. The results based on the RAD SNP datasets indicated hybridization Ligularia cyathiceps × L. duciformis and L. duciformis × L. yunnanensis were both restricted to F1 s plus a few first-generation backcrosses and no gene introgression were identified, giving rise to strong reproductive isolation among hybridizing species. Moreover, hybrid swarm simulation, using HYBRIDLAB, indicated the RAD SNP datasets had sufficient discriminatory power for accurate hybrid detection. We conclude that parental species show strong reproductive isolation and they still maintain species boundaries, which may be the key mechanism to maintain species diversity of Ligularia in the eastern Qinghai-Tibetan Plateau and adjacent areas. Moreover, this study highlights the effectiveness of RAD sequencing in hybridization studies.
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Affiliation(s)
- Ningning Zhang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yongpeng Ma
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
| | - Ryan A Folk
- Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA
| | - Jiaojun Yu
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
| | - Yuezhi Pan
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
| | - Xun Gong
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
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Zhang NN, Yu JJ, Wang YH, Gong X. Molecular evidence for asymmetric hybridization in three closely related sympatric species. AOB PLANTS 2018; 10:ply011. [PMID: 29492242 PMCID: PMC5824843 DOI: 10.1093/aobpla/ply011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 02/07/2018] [Indexed: 05/14/2023]
Abstract
Natural hybridization is common in plants and results in different evolutionary consequences to hybridizing species. Pre- and post-zygotic reproductive isolating barriers can impede hybridization between closely related species to maintain their species integrity. In Northwest Yunnan, three Ligularia species (Ligularia cyathiceps, L. duciformis and L. yunnanensis) and four types of morphologically intermediate individuals were discovered growing together in an area subject to human disturbance. In this study, we used three low-copy nuclear loci to test the natural hybridization hypothesis and the hybridization direction was ascertained by three chloroplast DNA fragments. The results indicated there were two hybridization groups at the study site, L. cyathiceps × L. duciformis and L. duciformis × L. yunnanensis, and two types of morphologically intermediate individuals were produced by L. cyathiceps and L. duciformis, and another two types were produced by L. duciformis and L. yunnanensis, while no hybrids between L. cyathiceps and L. yunnanensis were observed. Both hybridizing groups showed bidirectional but asymmetric hybridization and the factors influencing the symmetry are discussed. Most hybrids produced by the two hybridization groups seemed to be F1 generation. Hybrids with different morphologies within the same hybridization group showed similar genetic components. The results suggest that although human disturbance may promote natural hybridization among the three Ligularia species bringing them together, hybrids are limited to F1s and therefore species boundaries might be maintained.
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Affiliation(s)
- Ning-Ning Zhang
- Plant Science Institute, School of Life Sciences, Yunnan University, 650201 Kunming, Yunnan, China
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201 Kunming, Yunnan, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Jiao-Jun Yu
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201 Kunming, Yunnan, China
| | - Yue-Hua Wang
- Plant Science Institute, School of Life Sciences, Yunnan University, 650201 Kunming, Yunnan, China
| | - Xun Gong
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201 Kunming, Yunnan, China
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Zhang R, Gong X, Folk R. Evidence for continual hybridization rather than hybrid speciation between Ligularia duciformis and L. paradoxa (Asteraceae). PeerJ 2017; 5:e3884. [PMID: 29038755 PMCID: PMC5640982 DOI: 10.7717/peerj.3884] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 09/13/2017] [Indexed: 11/20/2022] Open
Abstract
Background Hybrids possess phenotypic traits that are often intermediate between their parental taxa, which commonly serves as evidence of hybridization in morphological analyses. Natural hybridization has been shown to occur frequently in Ligularia (Asteraceae). In a previous study, Ligularia ×maoniushanensis was demonstrated as a natural hybrid species between L. duciformis and L. paradoxa based on morphological and reproductive traits. Methods We used three chloroplast (cpDNA) fragments (psbA-trnH, trnL-rpl32 and trnQ-5′rps16), the nuclear ribosomal internal transcribed spacer (nrITS), and co-dominant SSR and dominant ISSR markers to study natural hybridization between L. duciformis and L. paradoxa growing sympatrically in two locations. Parental taxa were inferred using network analyses of cpDNA and nrITS haplotypes. Admixture among individuals was examined using the Bayesian clustering programs STRUCTURE and NewHybrids based on the SSR and ISSR data; and potential introgression in the SSR loci was assessed using the INTROGRESS package. Results The putative parental species were clearly distinguished from other sympatric Ligularia species by nrITS data, and L. ×maoniushanensis individuals were confirmed to be the hybrid offspring of L. duciformis and L. paradoxa. Moreover, introgression was detected among several individuals morphologically identified as L. duciformis or L. paradoxa. Analyses of the cpDNA data revealed primarily unidirectional hybridization between L. duciformis and L. paradoxa, with L. paradoxa as the maternal parent in Mt. Maoniu, whereas bidirectional but asymmetrical hybridization was inferred to occur in Heihai Lake. The STRUCTURE analyses based on the SSR data detected two distinct clusters among the three taxa. The NewHybrids analyses showed that individuals circumscribed as L. ×maoniushanensis were dominated by early- and later-generation and backcrossing hybrids. The NewHybrids results based on the ISSR data were congruent with SSR results. In addition, introgression was detected in some SSR loci, and heterogeneity among loci was found in terms of detected patterns of introgression. Conclusions Our data provide strong evidence for hybridization and introgression between L. duciformis and L. paradoxa. Ligularia ×maoniushanensis was demonstrated to be of hybrid origin. Since no evident reproductive isolation was found between the two parental species, detected hybrids appear to be part of hybrid swarms resulting from frequent and ongoing gene flow, which might impede the formation of a new hybrid species.
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Affiliation(s)
- Rong Zhang
- Key Laboratory of Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.,Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.,Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xun Gong
- Key Laboratory of Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.,Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Ryan Folk
- Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
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Zhang L, Xu P, Cai Y, Ma L, Li S, Li S, Xie W, Song J, Peng L, Yan H, Zou L, Ma Y, Zhang C, Gao Q, Wang J. The draft genome assembly of Rhododendron delavayi Franch. var. delavayi. Gigascience 2017; 6:1-11. [PMID: 29020749 PMCID: PMC5632301 DOI: 10.1093/gigascience/gix076] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/28/2017] [Accepted: 08/04/2017] [Indexed: 01/16/2023] Open
Abstract
Rhododendron delavayi Franch. is globally famous as an ornamental plant. Its distribution in southwest China covers several different habitats and environments. However, not much research had been conducted on Rhododendron spp. at the molecular level, which hinders understanding of its evolution, speciation, and synthesis of secondary metabolites, as well as its wide adaptability to different environments. Here, we report the genome assembly and gene annotation of R. delavayi var. delavayi (the second genome sequenced in the Ericaceae), which will facilitate the study of the family. The genome assembly will have further applications in genome-assisted cultivar breeding. The final size of the assembled R. delavayi var. delavayi genome (695.09 Mb) was close to the 697.94 Mb, estimated by k-mer analysis. A total of 336.83 gigabases (Gb) of raw Illumina HiSeq 2000 reads were generated from 9 libraries (with insert sizes ranging from 170 bp to 40 kb), achieving a raw sequencing depth of ×482.6. After quality filtering, 246.06 Gb of clean reads were obtained, giving ×352.55 coverage depth. Assembly using Platanus gave a total scaffold length of 695.09 Mb, with a contig N50 of 61.8 kb and a scaffold N50 of 637.83 kb. Gene prediction resulted in the annotation of 32 938 protein-coding genes. The genome completeness was evaluated by CEGMA and BUSCO and reached 95.97% and 92.8%, respectively. The gene annotation completeness was also evaluated by CEGMA and BUSCO and reached 97.01% and 87.4%, respectively. Genome annotation revealed that 51.77% of the R. delavayi genome is composed of transposable elements, and 37.48% of long terminal repeat elements (LTRs). The de novo assembled genome of R. delavayi var. delavayi (hereinafter referred to as R. delavayi) is the second genomic resource of the family Ericaceae and will provide a valuable resource for research on future comparative genomic studies in Rhododendron species. The availability of the R. delavayi genome sequence will hopefully provide a tool for scientists to tackle open questions regarding molecular mechanisms underlying environmental interactions in the genus Rhododendron, more accurately understand the evolutionary processes and systematics of the genus, facilitate the identification of genes encoding pharmaceutically important compounds, and accelerate molecular breeding to release elite varieties.
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Affiliation(s)
- Lu Zhang
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, National Engineering Research Center For Ornamental Horticulture, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
- Key Lab of Yunnan Flower Breeding, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
| | - Pengwei Xu
- BGI-Shenzhen, BGI Park, No. 21 Hongan 3rd Street, Yantian District, Shenzhen 518083, China
| | - Yanfei Cai
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, National Engineering Research Center For Ornamental Horticulture, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
- Key Lab of Yunnan Flower Breeding, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
| | - Lulin Ma
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, National Engineering Research Center For Ornamental Horticulture, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
- Key Lab of Yunnan Flower Breeding, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
| | - Shifeng Li
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, National Engineering Research Center For Ornamental Horticulture, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
- Key Lab of Yunnan Flower Breeding, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
| | - Shufa Li
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, National Engineering Research Center For Ornamental Horticulture, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
- Key Lab of Yunnan Flower Breeding, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
| | - Weijia Xie
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, National Engineering Research Center For Ornamental Horticulture, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
- Key Lab of Yunnan Flower Breeding, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
| | - Jie Song
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, National Engineering Research Center For Ornamental Horticulture, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
- Key Lab of Yunnan Flower Breeding, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
| | - Lvchun Peng
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, National Engineering Research Center For Ornamental Horticulture, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
- Key Lab of Yunnan Flower Breeding, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
| | - Huijun Yan
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, National Engineering Research Center For Ornamental Horticulture, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
- Key Lab of Yunnan Flower Breeding, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
| | - Ling Zou
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, National Engineering Research Center For Ornamental Horticulture, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
- Key Lab of Yunnan Flower Breeding, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
| | - Yongpeng Ma
- Kunming Botanical Garden, Kunming Institute of Botany, Chinese Academy of Sciences, No. 132 Lanhei Road, Panlong District, Kunming, Yunnan 650201, China
| | - Chengjun Zhang
- Germplasm Bank of Wild species, Kunming Institute of Botany, Chinese Academy of Sciences, No. 132 Lanhei Road, Panlong District, Kunming, Yunnan 650201, China
| | - Qiang Gao
- BGI-Shenzhen, BGI Park, No. 21 Hongan 3rd Street, Yantian District, Shenzhen 518083, China
| | - Jihua Wang
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, National Engineering Research Center For Ornamental Horticulture, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
- Key Lab of Yunnan Flower Breeding, No. 2238 Beijing Road, Panlong District, Kunming 650205, China
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Sun H, Zhang J, Deng T. Origins and evolution of plant diversity in the Hengduan Mountains, China. PLANT DIVERSITY 2017; 39:161-166. [PMID: 30159507 PMCID: PMC6112316 DOI: 10.1016/j.pld.2017.09.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 09/05/2017] [Indexed: 05/07/2023]
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Yan LJ, Burgess KS, Milne R, Fu CN, Li DZ, Gao LM. Asymmetrical natural hybridization varies among hybrid swarms between two diploid Rhododendron species. ANNALS OF BOTANY 2017; 120:51-61. [PMID: 28444136 PMCID: PMC5737508 DOI: 10.1093/aob/mcx039] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 03/14/2017] [Indexed: 05/23/2023]
Abstract
Background and Aims The extent to which hybridization leads to gene flow between plant species depends on the structure of hybrid populations. However, if this varies between locations, species barriers might prove permeable in some locations but not in others. To assess possible variation in hybrid population structure, the magnitude and direction of natural hybridization between two Chinese endemic species, Rhododendron spiciferum and Rhododendron spinuliferum , were evaluated. Methods Thirteen nuclear microsatellite markers were employed to characterize 566 individuals collected from 15 non-allopatric populations and nine allopatric parental populations. Chloroplast DNA (cpDNA) sequences were obtained from a subset of samples. Genetic structure and direction of gene flow was determined using a combination of STRUCTURE and NEWHYBRIDS analysis. Key Results Nuclear analysis revealed that parental taxa formed two genetically distinct clusters and hybrids shared the genetic background of both parents and did not form a separate genetic lineage. Overall, hybrid swarms were dominated by early- and later-generation hybrids, with a significantly higher proportion of hybrids (59·6 %) possessing >50 % R. spiciferum-like nuclear germplasm. The cpDNA analysis further indicated that a significantly greater proportion of hybrids (61·1 %) possessed the R. spiciferum cpDNA haplotype. Conclusions Gene flow between R. spiciferum and R. spinuliferum was found to be bidirectional in 14 of the 15 hybrid swarms and asymmetrical in six hybrid swarms. Asymmetrical gene flow was evident for only nuclear DNA (nDNA) in two populations, for only cpDNA in three populations, and for both nDNA and cpDNA in one population. Collectively, the variation in genetic structure found among the 15 hybrid swarms suggests that introgression rather than hybrid speciation is a more likely outcome of hybridization between these hybridizing taxa.
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Affiliation(s)
- Li-Jun Yan
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- College of Vocational and Technical Education, Yunnan Normal University, Kunming 650092, China
| | - Kevin S. Burgess
- Department of Biology, College of Letters & Sciences, Columbus State University, University System of Georgia, 163A LeNoir Hall, Columbus, GA 31907-5645, USA
| | - Richard Milne
- Institute of Molecular Plant Sciences, University of Edinburgh, King’s Buildings, Edinburgh EH9 3JH, UK
| | - Chao-Nan Fu
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - De-Zhu Li
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lian-Ming Gao
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
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Zhang JL, Ma YP, Wu ZK, Dong K, Zheng SL, Wang YY. Natural hybridization and introgression among sympatrically distributed Rhododendron species in Guizhou, China. BIOCHEM SYST ECOL 2017. [DOI: 10.1016/j.bse.2016.12.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Gao QB, Li Y, Gengji ZM, Gornall RJ, Wang JL, Liu HR, Jia LK, Chen SL. Population Genetic Differentiation and Taxonomy of Three Closely Related Species of Saxifraga (Saxifragaceae) from Southern Tibet and the Hengduan Mountains. FRONTIERS IN PLANT SCIENCE 2017; 8:1325. [PMID: 28804492 PMCID: PMC5532446 DOI: 10.3389/fpls.2017.01325] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 07/14/2017] [Indexed: 05/12/2023]
Abstract
The effects of rapid, recent uplift of the Hengduan Mountains on evolution and diversification of young floristic lineages still remain unclear. Here, we investigate diversification of three closely related Saxifraga species with a distribution restricted to the Hengduan Mountains (HM) and southern Tibet, and comment on their taxonomy based on molecular evidence. Three chloroplast DNA fragments (rbcL, trnL-F, trnS-G) and the nuclear ribosomal DNA internal transcribed spacer (ITS) were employed to study genetic structure across 104 individuals from 12 populations of Saxifraga umbellulata, S. pasumensis, and S. banmaensis. Chloroplast DNA (cpDNA) phylogenies revealed two well supported clades, corresponding to S. umbellulata and S. pasumensis plus S. banmaensis. Topology of the ITS phylogeny was largely congruent with that generated from cpDNA haplotypes, but with minor conflicts which might be caused by incomplete lineage sorting. Analyses of molecular variance of both cpDNA and ITS datasets revealed that most variation was held between S. pasumensis s.l. (with S. banmaensis) and S. umbellulata (92.31% for cpDNA; 69.78% for ITS), suggesting a high degree of genetic divergence between them. Molecular clock analysis based on ITS dataset suggested that the divergence between S. pasumensis s.l. and S. umbellulata can be dated to 8.50 Ma, probably a result of vicariant allopatric diversification associated with the uplift events of the HM. Vicariance associated with HM uplifts may also have been responsible for infraspecific differentiation in S. pasumensis. In contrast, infraspecific differentiation in S. umbellulata was most likely triggered by Quaternary glaciations. The much lower levels of gene diversity within populations of S. pasumensis compared with S. umbellulata could have resulted from both range contractions and human collection on account of its putative medicinal properties. Combining evidence from morphology, geographical distributions and molecular phylogenetic data, we recommend that S. banmaensis should be treated as a synonym of S. pasumensis which in turn, and based on the same sources of evidence, should be treated as a separate species rather than as a variety of S. umbellulata.
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Affiliation(s)
- Qing-Bo Gao
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of SciencesXining, China
- Key Laboratory of Crop Molecular Breeding of Qinghai Province, Northwest Institute of Plateau Biology, Chinese Academy of SciencesXining, China
| | - Yan Li
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of SciencesXining, China
- University of Chinese Academy of SciencesBeijing, China
| | - Zhuo-Ma Gengji
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of SciencesXining, China
- University of Chinese Academy of SciencesBeijing, China
| | - Richard J. Gornall
- Department of Genetics, University of LeicesterLeicester, United Kingdom
| | - Jiu-Li Wang
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of SciencesXining, China
- University of Chinese Academy of SciencesBeijing, China
| | - Hai-Rui Liu
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of SciencesXining, China
- University of Chinese Academy of SciencesBeijing, China
| | - Liu-Kun Jia
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of SciencesXining, China
- University of Chinese Academy of SciencesBeijing, China
| | - Shi-Long Chen
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of SciencesXining, China
- *Correspondence: Shi-Long Chen
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Marczewski T, Ma YP, Zhang XM, Sun WB, Marczewski AJ. Why is population information crucial for taxonomy? A case study involving a hybrid swarm and related varieties. AOB PLANTS 2016; 8:plw070. [PMID: 27758764 PMCID: PMC5142052 DOI: 10.1093/aobpla/plw070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 09/14/2016] [Indexed: 05/14/2023]
Abstract
Hybridization has become a focal topic in evolutionary biology, and many taxonomists are aware that the process occurs more frequently than previously assumed. Nonetheless many species and varieties are still described without explicitly considering the possibility of hybridization, especially in countries that have relatively short scientific histories, but which often possess the highest species diversities. Furthermore, new taxa are often described based only on herbarium specimens, not taking into account information from wild populations, significantly decreasing the potential to detect morphologies arising from hybridization at this crucial descriptive stage. We used morphological data from a hybrid swarm involving two Rhododendron species to showcase possible character combinations in intermediates. Certain characters used to distinguish taxa were more variable within the same individual than between species, emphasizing the importance of population information for an adequate choice of characters. Most described varieties of the two species fell within the spectrum of hybrid morphology, suggesting that these taxa would be unlikely to have merited formal description if contemporary standards had been employed. In all investigated cases the hybrid nature of described varieties seems to have been detectable with adequate morphological data alone, if populations had been assessed. A post hoc assessment of taxa is often complicated, especially if certain types of information are not provided. To avoid accumulation of such invalid taxa, careful scrutiny should be employed for new descriptions. Hybrids (not hybrid species) described as taxa obscure valuable information about natural processes and impact negatively on further research that depends on taxonomic data.
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Affiliation(s)
- Tobias Marczewski
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
| | - Yong-Peng Ma
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
| | - Xue-Mei Zhang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
| | - Wei-Bang Sun
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
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Gramlich S, Hörandl E. Fitness of natural willow hybrids in a pioneer mosaic hybrid zone. Ecol Evol 2016; 6:7645-7655. [PMID: 30128118 PMCID: PMC6093150 DOI: 10.1002/ece3.2470] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 08/10/2016] [Accepted: 08/24/2016] [Indexed: 01/20/2023] Open
Abstract
Hybrid fitness is an important parameter to predict the evolutionary consequences of a hybridization event and to characterize hybrid zones. We studied fitness parameters of F1 and later-generation hybrids between the lowland species Salix purpurea and the alpine S. helvetica that have recently emerged during colonization of an alpine glacier forefield. Fruit production (number of capsules per catkin and fruit set) did not differ between hybrids and parents, but the number of seeds per capsule of F1 hybrids was slightly lower than that of later-generation hybrids and of the parents. Germination rates and seedling growth were tested on three substrates (pH 4.5, 7.0, and 8.0). Germination rates of seeds collected from F1 hybrids were lower on acid and neutral substrates, but equal at pH 8.0 compared to all other groups, while the seeds from later-generation hybrids performed as well as the parents on all three substrates. In seedling growth, the colonizer S. purpurea performed better than all other taxa on all three substrates, while hybrids resembled the subalpine species S. helvetica. Results suggest that endogenous selection acts against F1 hybrids, but favors fitter genotypes in later-generation hybrids. Exogenous selection via soil pH appears to be weak during seedling establishment. The pioneer vegetation on the glacier forefield may offer sufficient niche space for hybrid seedlings. Owing to the relatively high fitness of the hybrids and the scattered distribution of hybrids and parental individuals on the glacier forefield, this hybrid zone can be assigned to a mosaic model, probably facilitating gene flow and introgression between the parental species. As establishment of the hybrid zone appears to be linked to a colonization process, we propose to call it a pioneer mosaic hybrid zone.
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Affiliation(s)
- Susanne Gramlich
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium)Georg August University GöttingenGöttingenGermany
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium)Georg August University GöttingenGöttingenGermany
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Zha HG, Milne RI, Zhou HX, Chen XY, Sun H. Identification and cloning of class II and III chitinases from alkaline floral nectar of Rhododendron irroratum, Ericaceae. PLANTA 2016; 244:805-818. [PMID: 27189006 DOI: 10.1007/s00425-016-2546-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 05/06/2016] [Indexed: 06/05/2023]
Abstract
Class II and III chitinases belonging to different glycoside hydrolase families were major nectarins in Rhododendron irroratum floral nectar which showed significant chitinolytic activity. Previous studies have demonstrated antimicrobial activity in plant floral nectar, but the molecular basis for the mechanism is still poorly understood. Two chitinases, class II (Rhchi2) and III (Rhchi3), were characterized from alkaline Rhododendron irroratum nectar by both SDS-PAGE and mass spectrometry. Rhchi2 (27 kDa) and Rhchi3 (29 kDa) are glycoside hydrolases (family 19 and 18) with theoretical pI of 8.19 and 7.04. The expression patterns of Rhchi2 and Rhchi3 were analyzed by semi-quantitative RT-PCR. Rhchi2 is expressed in flowers (corolla nectar pouches) and leaves while Rhchi3 is expressed in flowers. Chitinase in concentrated protein and fresh nectar samples was visualised by SDS-PAGE and chitinolytic activity in fresh nectar was determined spectrophotometrically via chitin-azure. Full length gene sequences were cloned with Tail-PCR and RACE. The amino acid sequence deduced from the coding region for these proteins showed high identity with known chitinases and predicted to be located in extracellular space. Fresh R. irroratum floral nectar showed significant chitinolytic activity. Our results demonstrate that class III chitinase (GH 18 family) also exists in floral nectar. The functional relationship between class II and III chitinases and the role of these pathogenesis-related proteins in antimicrobial activity in nectar is suggested.
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Affiliation(s)
- Hong-Guang Zha
- College of Life and Environment Sciences, Huangshan University, Anhui, 245041, China.
| | - Richard I Milne
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, EH9 3JH, UK
- Royal Botanic Garden, Edinburgh, EH3 5LR, UK
| | - Hong-Xia Zhou
- College of Life and Environment Sciences, Huangshan University, Anhui, 245041, China
| | - Xiang-Yang Chen
- College of Life and Environment Sciences, Huangshan University, Anhui, 245041, China
| | - Hang Sun
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650204, China
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Zelener N, Tosto D, de Oliveira LO, Soldati MC, Inza MV, Fornes LF. Molecular evidence of hybrid zones of Cedrela (Meliaceae) in the Yungas of Northwestern Argentina. Mol Phylogenet Evol 2016; 102:45-55. [PMID: 27215942 DOI: 10.1016/j.ympev.2016.05.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 10/21/2022]
Abstract
In the Yungas of Northwestern Argentina, three endangered species of Cedrela (C. angustifolia, C. saltensis, and C. balansae) follow altitudinal gradients of distribution with contact zones between them. We sampled 210 individuals from 20 populations that spanned most of Cedrela's geographical range in the Yungas, and used Amplified Fragment Length Polymorphism (AFLP) markers and DNA sequences of the nuclear Internal Transcribed Spacer (ITS) to investigate hybrid zones. Data analyses employed an array of complementary methods, including principal coordinate analyses, Bayesian clustering analyses, maximum likelihood tree-building, and network techniques. Both nuclear molecular systems - AFLP and ITS - provided insights into the evolutionary history of Cedrela in the Yungas in a congruent manner. We uncovered strong support for the occurrence of natural hybridization between C. balansae and C. saltensis. Additionally, we identified hybrid zones in areas of sympatry (at both the Calilegua National Park and the San Andrés farm) and in transition zones from 820 to 1100meters above sea level (localities of Pintascayo and Acambuco). There was no evidence for hybridization of either C. balansae or C. saltensis with C. angustifolia. The role of hybrid populations in conservation and use of genetic resources in the Yungas were discussed.
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Affiliation(s)
- Noga Zelener
- Instituto de Recursos Biológicos, INTA Castelar-CIRN-CNIA, De los Reseros y N. Repetto (ex Las Cabañas) s.n., Hurlingham 1686, Buenos Aires, Argentina.
| | - Daniela Tosto
- Instituto de Biotecnología, INTA Castelar-CICVyA-CNIA, De los Reseros y N. Repetto (ex Las Cabañas) s.n., Hurlingham 1686, Buenos Aires, Argentina.
| | - Luiz Orlando de Oliveira
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brazil.
| | - María Cristina Soldati
- Instituto de Recursos Biológicos, INTA Castelar-CIRN-CNIA, De los Reseros y N. Repetto (ex Las Cabañas) s.n., Hurlingham 1686, Buenos Aires, Argentina.
| | - María Virginia Inza
- Instituto de Recursos Biológicos, INTA Castelar-CIRN-CNIA, De los Reseros y N. Repetto (ex Las Cabañas) s.n., Hurlingham 1686, Buenos Aires, Argentina.
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Jiang D, Feng J, Dong M, Wu G, Mao K, Liu J. Genetic origin and composition of a natural hybrid poplar Populus × jrtyschensis from two distantly related species. BMC PLANT BIOLOGY 2016; 16:89. [PMID: 27091174 PMCID: PMC4836070 DOI: 10.1186/s12870-016-0776-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 04/13/2016] [Indexed: 05/05/2023]
Abstract
BACKGROUND The factors that contribute to and maintain hybrid zones between distinct species are highly variable, depending on hybrid origins, frequencies and fitness. In this study, we aimed to examine genetic origins, compositions and possible maintenance of Populus × jrtyschensis, an assumed natural hybrid between two distantly related species. This hybrid poplar occurs mainly on the floodplains along the river valleys between the overlapping distributions of the two putative parents. RESULTS We collected 566 individuals from 45 typical populations of P. × jrtyschensis, P. nigra and P. laurifolia. We genotyped them based on the sequence variations of one maternally inherited chloroplast DNA (cpDNA) fragment and genetic polymorphisms at 20 SSR loci. We further sequenced eight nuclear genes for 168 individuals from 31 populations. Two groups of cpDNA haplotypes characteristic of P. nigra and P. laurifolia respectively were both recovered for P. × jrtyschensis. Genetic structures and coalescent tests of two sets of nuclear population genetic data suggested that P. × jrtyschensis originated from hybridizations between the two assumed parental species. All examined populations of P. × jrtyschensis comprise mainly F1 hybrids from interspecific hybridizations between P. nigra and P. laurifolia. In the habitats of P. × jrtyschensis, there are lower concentrations of soil nitrogen than in the habitats occupied by the other two species. CONCLUSIONS Our extensive examination of the genetic composition of P. × jrtyschensis suggested that it is typical of F1-dominated hybrid zones. This finding plus the low concentration of soil nitrogen in the floodplain soils support the F1-dominated bounded hybrid superiority hypothesis of hybrid zone maintenance for this particular hybrid poplar.
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Affiliation(s)
- Dechun Jiang
- />State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu People’s Republic of China
| | - Jianju Feng
- />State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu People’s Republic of China
- />College of Plant Sciences, Xinjiang Production & Construction Corps Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin, Tarimu University, Alar, Xinjiang People’s Republic of China
| | - Miao Dong
- />State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu People’s Republic of China
| | - Guili Wu
- />State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu People’s Republic of China
| | - Kangshan Mao
- />State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu People’s Republic of China
| | - Jianquan Liu
- />State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu People’s Republic of China
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Strong reproductive isolation despite occasional hybridization between a widely distributed and a narrow endemic Rhododendron species. Sci Rep 2016; 6:19146. [PMID: 26751844 PMCID: PMC4707479 DOI: 10.1038/srep19146] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/07/2015] [Indexed: 12/29/2022] Open
Abstract
Reproductive isolation (RI) plays an important role for speciation, but assessing reproductive barriers at all life-cycle stages remains challenging. In plants, most studies addressing the topic have been focusing on herbs with short generation times. The present study attempted to quantify several reproductive barriers between a hybridizing species pair of long-lived woody rhododendrons. Consistent with findings of previous studies, pre-zygotic reproductive barriers contributed more to total RI than post-zygotic reproductive barriers. Especially in the more widespread species geographic isolation was an important barrier, and pollinator constancy contributed exceptionally to RI in both species. Additionally to strong pre-zygotic reproductive barriers, post-zygotic reproductive barriers were considerable, and had asymmetric tendencies favoring one of the species as maternal parent. Overall, despite occasional hybridization, the present study provides evidence for strong RI between R. cyanocarpum and R. delavayi.
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Zhang JJ, Montgomery BR, Huang SQ. Evidence for asymmetrical hybridization despite pre- and post-pollination reproductive barriers between two Silene species. AOB PLANTS 2016; 8:plw032. [PMID: 27178066 PMCID: PMC4940505 DOI: 10.1093/aobpla/plw032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 04/27/2016] [Indexed: 05/14/2023]
Abstract
Interspecific hybridization is widespread among plants; nevertheless, pre- and post-zygotic isolating mechanisms may maintain species integrity for interfertile species in sympatry despite some gene flow. Interspecific hybridization and potential isolating barriers were evaluated between co-flowering Silene asclepiadea and Silene yunnanensis in an alpine community in southwest China. We investigated morphological and molecular (nuclear microsatellites and chloroplast gene sequence) variation in sympatric populations of S. asclepiadea and S. yunnanensis. Additionally, we analyzed pollinator behaviour and compared reproductive success between the putative hybrids and their parental species. Both the molecular and morphological data indicate that there were putative natural hybrids in the field, with S. asclepiadae the ovule parent and S. yunnanensis the pollen parent. Bumblebees were the primary visitors to S. asclepiadae and putative hybrids, while butterflies were the primary visitors to S. yunnanensis Pollen production and viability were significantly lower in putative hybrids than the parental species. The direction of hybridization is quite asymmetric from S. yunnanensis to S. asclepiadea Protandry combined with later peak flowering of S. yunnanensis, and pollinator preference may have contributed to the asymmetric pattern of hybridization, but putative hybrids were rare. Our results thus suggest that despite gene flow, S. asclepiadea and S. yunnanensis can maintain species boundaries, perhaps as a result of floral isolation and low fecundity of the hybrids.
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Affiliation(s)
- Jin-Ju Zhang
- School of Life Sciences, Central China Normal University, Wuhan 430079, China State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Benjamin R Montgomery
- Division of Natural Sciences & Engineering, University of South Carolina Upstate, Spartanburg, SC 29303, USA
| | - Shuang-Quan Huang
- School of Life Sciences, Central China Normal University, Wuhan 430079, China
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Marczewski T, Chamberlain DF, Milne RI. Hybridization in closely related Rhododendron species: half of all species-differentiating markers experience serious transmission ratio distortion. Ecol Evol 2015; 5:3003-22. [PMID: 26357534 PMCID: PMC4559045 DOI: 10.1002/ece3.1570] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 05/18/2015] [Accepted: 05/19/2015] [Indexed: 01/29/2023] Open
Abstract
An increasing number of studies of hybridization in recent years have revealed that complete reproductive isolation between species is frequently not finalized in more or less closely related organisms. Most of these species do, however, seem to retain their phenotypical characteristics despite the implication of gene flow, highlighting the remaining gap in our knowledge of how much of an organism’s genome is permeable to gene flow, and which factors promote or prevent hybridization. We used AFLP markers to investigate the genetic composition of three populations involving two interfertile Rhododendron species: two sympatric populations, of which only one contained hybrids, and a further hybrid-dominated population. No fixed differences between the species were found, and only 5.8% of the markers showed some degree of species differentiation. Additionally, 45.5% of highly species-differentiating markers experienced significant transmission distortion in the hybrids, which was most pronounced in F1 hybrids, suggesting that factors conveying incompatibilities are still segregating within the species. Furthermore, the two hybrid populations showed stark contrasting composition of hybrids; one was an asymmetrically backcrossing hybrid swarm, while in the other, backcrosses were absent, thus preventing gene flow.
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Affiliation(s)
- Tobias Marczewski
- Royal Botanic Garden Edinburgh 20A Inverleith Row, Edinburgh, EH3 5LR, UK ; Institute of Molecular Plant Sciences, University of Edinburgh Mayfield Road, Edinburgh, EH9 3JH, UK
| | | | - Richard I Milne
- Royal Botanic Garden Edinburgh 20A Inverleith Row, Edinburgh, EH3 5LR, UK ; Institute of Molecular Plant Sciences, University of Edinburgh Mayfield Road, Edinburgh, EH9 3JH, UK
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Su X, Wu G, Li L, Liu J. Species delimitation in plants using the Qinghai-Tibet Plateau endemic Orinus (Poaceae: Tridentinae) as an example. ANNALS OF BOTANY 2015; 116:35-48. [PMID: 25987712 PMCID: PMC4479750 DOI: 10.1093/aob/mcv062] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Revised: 11/27/2014] [Accepted: 03/31/2015] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS Accurate identification of species is essential for the majority of biological studies. However, defining species objectively and consistently remains a challenge, especially for plants distributed in remote regions where there is often a lack of sufficient previous specimens. In this study, multiple approaches and lines of evidence were used to determine species boundaries for plants occurring in the Qinghai-Tibet Plateau, using the genus Orinus (Poaceae) as a model system for an integrative approach to delimiting species. METHODS A total of 786 individuals from 102 populations of six previously recognized species were collected for niche, morphological and genetic analyses. Three plastid DNA regions (matK, rbcL and trnH-psbA) and one nuclear DNA region [internal transcribed space (ITS)] were sequenced. KEY RESULTS Whereas six species had been previously recognized, statistical analyses based on character variation, molecular data and niche differentiation identified only two well-delimited clusters, together with a third possibly originating from relatively recent hybridization between, or historical introgression from, the other two. CONCLUSIONS Based on a principle of integrative species delimitation to reconcile different sources of data, the results provide compelling evidence that the six previously recognized species of the genus Orinus that were examined should be reduced to two, with new circumscriptions, and a third, identified in this study, should be described as a new species. This empirical study highlights the value of applying genetic differentiation, morphometric statistics and ecological niche modelling in an integrative approach to re-circumscribing species boundaries. The results produce relatively objective, operational and unbiased taxonomic classifications of plants occurring in remote regions.
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Affiliation(s)
- Xu Su
- State Key Laboratory of Grassland Agro-Ecosystem, School of Life Science, Lanzhou University, Lanzhou 730000, PR China and Key Laboratory of Education Ministry of Environments and Resources in the Qinghai-Tibet Plateau, School of Geography and Life Science, Qinghai Normal University, Xining 810008, PR China State Key Laboratory of Grassland Agro-Ecosystem, School of Life Science, Lanzhou University, Lanzhou 730000, PR China and Key Laboratory of Education Ministry of Environments and Resources in the Qinghai-Tibet Plateau, School of Geography and Life Science, Qinghai Normal University, Xining 810008, PR China
| | - Guili Wu
- State Key Laboratory of Grassland Agro-Ecosystem, School of Life Science, Lanzhou University, Lanzhou 730000, PR China and Key Laboratory of Education Ministry of Environments and Resources in the Qinghai-Tibet Plateau, School of Geography and Life Science, Qinghai Normal University, Xining 810008, PR China
| | - Lili Li
- State Key Laboratory of Grassland Agro-Ecosystem, School of Life Science, Lanzhou University, Lanzhou 730000, PR China and Key Laboratory of Education Ministry of Environments and Resources in the Qinghai-Tibet Plateau, School of Geography and Life Science, Qinghai Normal University, Xining 810008, PR China
| | - Jianquan Liu
- State Key Laboratory of Grassland Agro-Ecosystem, School of Life Science, Lanzhou University, Lanzhou 730000, PR China and Key Laboratory of Education Ministry of Environments and Resources in the Qinghai-Tibet Plateau, School of Geography and Life Science, Qinghai Normal University, Xining 810008, PR China
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Li Y, Maki M. Variation in the frequency and extent of hybridization between Leucosceptrum japonicum and L. stellipilum (Lamiaceae) in the Central Japanese Mainland. PLoS One 2015; 10:e0116411. [PMID: 25738505 PMCID: PMC4349587 DOI: 10.1371/journal.pone.0116411] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 12/09/2014] [Indexed: 11/18/2022] Open
Abstract
Variations in the frequency and extent of hybridization among mixed populations located in the same contact zone provide natural laboratories for the study of extrinsic reproductive isolation maintaining species integrity. In this study, we examined the pattern of hybridization between L. japonicum and L. stellipilum among mixed populations in different localities of a contact zone. The genetic structures from three sympatric populations and six mixed populations in the hybrid zone, and five reference populations far from the contact zone, were characterized using 10 neutral nuclear microsatellite markers. Evidence from genetic distance-based clustering analysis, the frequency distribution of admixture proportion values, and the hybrid category assignment approaches indicated that the frequency and extent of hybridization varied considerably among populations in the contact zone between L. japonicum and L. stellipilum. One likely explanation is that variation in exogenous (ecological) selection among populations might contribute to differences in frequency and extent of hybridization. The present study will facilitate future research exploring the evolution of reproductive isolation between L. japonicum and L. stellipilum.
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Affiliation(s)
- Yue Li
- Division of Plant Evolutionary Biology, Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Aoba, Sendai 980–8578, Japan
- Botanical Gardens, Tohoku University, Kawauchi 12–2, Aoba, Sendai 980–0862, Japan
| | - Masayuki Maki
- Botanical Gardens, Tohoku University, Kawauchi 12–2, Aoba, Sendai 980–0862, Japan
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Yan LJ, Liu J, Möller M, Zhang L, Zhang XM, Li DZ, Gao LM. DNA barcoding ofRhododendron(Ericaceae), the largest Chinese plant genus in biodiversity hotspots of the Himalaya-Hengduan Mountains. Mol Ecol Resour 2014; 15:932-44. [DOI: 10.1111/1755-0998.12353] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Revised: 11/22/2014] [Accepted: 11/26/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Li-Jun Yan
- Key Laboratory for Plant Diversity and Biogeography of East Asia; Kunming Institute of Botany; Chinese Academy of Sciences; Kunming 650201 Yunnan China
- Germplasm Bank of Wild Species; Kunming Institute of Botany; Chinese Academy of Sciences; Kunming 650201 Yunnan China
- University of Chinese Academy of Sciences; Beijing 100049 China
| | - Jie Liu
- Key Laboratory for Plant Diversity and Biogeography of East Asia; Kunming Institute of Botany; Chinese Academy of Sciences; Kunming 650201 Yunnan China
| | - Michael Möller
- Key Laboratory for Plant Diversity and Biogeography of East Asia; Kunming Institute of Botany; Chinese Academy of Sciences; Kunming 650201 Yunnan China
- Royal Botanic Garden Edinburgh; 20A Inverleith Row Edinburgh EH3 5LR UK
| | - Lin Zhang
- Key Laboratory for Plant Diversity and Biogeography of East Asia; Kunming Institute of Botany; Chinese Academy of Sciences; Kunming 650201 Yunnan China
- University of Chinese Academy of Sciences; Beijing 100049 China
| | - Xue-Mei Zhang
- Landscape and Horticultural College; Yunnan Agricultural University; Kunming 650201 Yunnan China
| | - De-Zhu Li
- Key Laboratory for Plant Diversity and Biogeography of East Asia; Kunming Institute of Botany; Chinese Academy of Sciences; Kunming 650201 Yunnan China
- Germplasm Bank of Wild Species; Kunming Institute of Botany; Chinese Academy of Sciences; Kunming 650201 Yunnan China
| | - Lian-Ming Gao
- Key Laboratory for Plant Diversity and Biogeography of East Asia; Kunming Institute of Botany; Chinese Academy of Sciences; Kunming 650201 Yunnan China
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Balao F, García-Castaño JL. AFLPsim: an R package to simulate and detect dominant markers under selection in hybridizing populations. PLANT METHODS 2014; 10:40. [PMID: 25926861 PMCID: PMC4413549 DOI: 10.1186/1746-4811-10-40] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 11/24/2014] [Indexed: 06/04/2023]
Abstract
BACKGROUND In spite of a large diversity of approaches to investigate loci under selection from a population genetic perspective, very few programs have been specifically designed to date to test selection in hybrids using dominant markers. In addition, simulators of dominant markers are very scarce and they do not usually take into account hybridization. RESULTS Here, we present a new, multifunctional, R package for dominant genetic markers, AFLPsim. This package can simulate dominant markers in hybridizing populations and implements genome scan methods for detecting outlier dominant loci in hybrids. In addition, it includes tools for further manipulating the results, plotting them and other tasks. We describe and tabulate the major functions implemented in AFLPsim. In addition, we provide some demonstration of its use and we perform a comparative study with other software. Finally, we conclude by briefly describing the input and output formats. CONCLUSIONS The R package AFLPsim application provides several useful tools in the context of hybridization studies. It can simulate dominant markers in hybridizing populations and predict their demographic evolution. In addition, we implement a new genome scan method for detecting outlier dominant loci in hybrids, which shows a rather high sensitivity and is very conservative in comparison with Gagnaire et al.'s, Bayescan and introgress. The application is downloadable at http://cran.r-project.org/web/packages/AFLPsim/.
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Affiliation(s)
- Francisco Balao
- />Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Ap-1095, 41080 Sevilla, Spain
- />Department of Systematic and Evolutionary Botany, University of Vienna, Rennweg 14, Vienna, 1030 Austria
| | - Juan Luis García-Castaño
- />Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Ap-1095, 41080 Sevilla, Spain
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Fan Q, Chen S, Li M, Guo W, Jing H, Wu W, Zhou R, Liao W. Molecular evidence for natural hybridization between wild loquat (Eriobotrya japonica) and its relative E. prinoides. BMC PLANT BIOLOGY 2014; 14:275. [PMID: 25300306 PMCID: PMC4196008 DOI: 10.1186/s12870-014-0275-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 10/03/2014] [Indexed: 05/14/2023]
Abstract
BACKGROUND Interspecific hybridization has long been recognized as a pivotal process in plant evolution and speciation. It occurs fairly common in the genera of the subtribe Pyrinae. In Eriobotrya, a small tree genus of Pyrinae, E. prinoides var. daduheensis has been recognized as either a variety of E. prinoides, a natural hybrid between E. prinoides and E. japonica, or a variety of E. japonica. However, to date, there has been no convincing evidence on its status. RESULTS Four nuclear genes and two chloroplast regions were sequenced in 89 individuals of these three Eriobotrya taxa from two locations where they coexist. A few fixed nucleotide substitutions or gaps were found in each of the investigated nuclear and chloroplast loci between E. japonica and E. prinoides. Of the 35 individuals of E. prinoides var. daduheensis, 33 showed nucleotide additivity of E. japonica and E. prinoides in at least one nuclear gene, and 10 of them harboured nucleotide additivity at all the four nuclear genes. Most haplotypes of E. prinoides var. daduheensis were also shared with those of E. japonica and E. prinoides. In the two chloroplast regions, 28 and 7 individuals were identical with E. japonica and E. prinoides, respectively. CONCLUSIONS Our study provides compelling evidence for a hybrid status for E. prinoides var. daduheensis. Most hybrid individuals are later-generation hybrids. Both E. japonica and E. prinoides can serve as female parent. Differential adaptation might maintain the species boundary of E. prinoides and E. japonica in the face of hybridization and potential introgression.
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Affiliation(s)
- Qiang Fan
- />Guangdong Key Laboratory of Plant Resources, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 China
| | - Sufang Chen
- />Guangdong Key Laboratory of Plant Resources, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 China
| | - Mingwan Li
- />Guangdong Key Laboratory of Plant Resources, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 China
| | - Wei Guo
- />Department of Horticulture and Landscape Architecture, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225 China
| | - Huijuan Jing
- />Guangdong Key Laboratory of Plant Resources, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 China
| | - Wei Wu
- />South China Botanical Garden, Chinese Academy of Science, Guangzhou, 510650 China
| | - Renchao Zhou
- />Guangdong Key Laboratory of Plant Resources, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 China
| | - Wenbo Liao
- />Guangdong Key Laboratory of Plant Resources, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 China
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Ma Y, Xie W, Tian X, Sun W, Wu Z, Milne R. Unidirectional hybridization and reproductive barriers between two heterostylous primrose species in north-west Yunnan, China. ANNALS OF BOTANY 2014; 113:763-75. [PMID: 24492637 PMCID: PMC3962241 DOI: 10.1093/aob/mct312] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 12/13/2013] [Indexed: 05/14/2023]
Abstract
BACKGROUND AND AIMS Heteromorphy in flowers has a profound effect on breeding patterns within a species, but little is known about how it affects reproductive barriers between species. The heterostylous genus Primula is very diverse in the Himalaya region, but hybrids there have been little researched. This study examines in detail a natural hybrid zone between P. beesiana and P. bulleyana. METHODS Chloroplast sequencing, AFLP (amplified fragment length polymorphism) markers and morphological comparisons were employed to characterize putative hybrids in the field, using synthetic F1s from hand pollination as controls. Pollinator visits to parent species and hybrids were observed in the field. Hand pollinations were conducted to compare pollen tube growth, seed production and seed viability for crosses involving different morphs, species and directions of crossing. KEY RESULTS Molecular data revealed all hybrid derivatives examined to be backcrosses of first or later generations towards P. bulleyana: all had the chloroplast DNA (cpDNA) of this species. Some individuals had morphological traits suggesting they were hybrids, but they were genetically similar to P. bulleyana; they might have been advanced generation backcrosses. Viable F1s could not be produced with P. bulleyana pollen on P. beesiana females, irrespective of the flower morphs used. Within-morph crosses for each species had very low (<10 %) seed viability, whereas crosses between pin P. bulleyana (female) and pin P. beesiana had a higher seed viability of 30 %. Thus genetic incompatibility mechanisms back up mechanical barriers to within-morph crosses in each species, but are not the same between the two species. The two species share their main pollinators, and pollinators were observed to fly between P. bulleyana and hybrids, suggesting that pollinator behaviour may not be an important isolating factor. CONCLUSIONS Hybridization is strongly asymmetric, with P. bulleyana the only possible mother and all detected hybrids being backcrosses in this direction. Partial ecological isolation and inhibition of heterospecific pollen, and possibly complete barriers to F1 formation on P. beesiana, may be enough to make F1 formation very rare in these species. Therefore, with no F1 detected, this hybrid zone may have a finite life span as successive generations become more similar to P. bulleyana.
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Affiliation(s)
- Yongpeng Ma
- Kunming Botanical Garden, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China
| | - Weijia Xie
- Flower research institute, Yunnan Academy of Agriculture Sciences, Kunming 650201, PR China
| | - Xiaoling Tian
- Kunming Botanical Garden, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China
| | - Weibang Sun
- Kunming Botanical Garden, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China
| | - Zhikun Wu
- Kunming Botanical Garden, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China
| | - Richard Milne
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3JH, UK
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Wen J, Zhang JQ, Nie ZL, Zhong Y, Sun H. Evolutionary diversifications of plants on the Qinghai-Tibetan Plateau. Front Genet 2014; 5:4. [PMID: 24575120 PMCID: PMC3921583 DOI: 10.3389/fgene.2014.00004] [Citation(s) in RCA: 227] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 01/06/2014] [Indexed: 11/13/2022] Open
Abstract
The Qinghai-Tibetan Plateau (QTP) is the highest and one of the most extensive plateaus in the world. Phylogenetic, phylogeographic, and ecological studies support plant diversifications on the QTP through multiple mechanisms such as allopatric speciation via geographic isolation, climatic oscillations and divergences, pollinator-mediated isolation, diploid hybridization and introgression, and allopolyploidy. These mechanisms have driven spectacular radiations and/or species diversifications in various groups of plants such as Pedicularis L., Saussurea DC., Rhododendron L., Primula L., Meconopsis Vig., Rhodiola L., and many lineages of gymnosperms. Nevertheless, much work is needed toward understanding the evolutionary mechanisms of plant diversifications on the QTP. Well-sampled biogeographic analyses of the QTP plants in the broad framework of the Northern Hemisphere as well as the Southern Hemisphere are still relatively few and should be encouraged in the next decade. This paper reviews recent evidence from phylogenetic and biogeographic studies in plants, in the context of rapid radiations, mechanisms of species diversifications on the QTP, and the biogeographic significance of the QTP in the broader context of both the Northern and Southern Hemisphere biogeography. Integrative multidimensional analyses of phylogeny, morphological innovations, geography, ecology, development, species interactions and diversifications, and geology are needed and should shed insights into the patterns of evolutionary assembly and radiations in this fascinating region.
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Affiliation(s)
- Jun Wen
- Department of Botany, National Museum of Natural History, MRC 166, Smithsonian Institution Washington, DC, USA
| | | | - Ze-Long Nie
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences Kunming, China
| | - Yang Zhong
- Institute of Biodiversity Science and Geobiology, Tibet University Lhasa, China ; School of Life Sciences, Fudan University Shanghai, China
| | - Hang Sun
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences Kunming, China
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Du GH, Zhang ZQ, Li QJ. Morphological and molecular evidence for natural hybridization in sympatric population of Roscoea humeana and R. cautleoides (Zingiberaceae). JOURNAL OF PLANT RESEARCH 2012; 125:595-603. [PMID: 22351043 DOI: 10.1007/s10265-012-0478-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 01/19/2012] [Indexed: 05/31/2023]
Abstract
The sympatric occurrence of some species in Roscoea is very common, but little information is available on natural hybridization. However, some intermediate individuals were found on the sympatric population of Roscoea humeana and R. cautleoides at Ganhaizi population in northwestern Yunnan Province, China. We suspected that these intermediate individuals were the hybrids of R. humeana and R. cautleoides from the previous evidence, but could not confirm them. In this study, morphometric analysis was followed by examination of HAT-RAPD polymorphisms to determine the occurrence of natural hybridization between sympatric R. humeana and R. cautleoides. The results showed that most morphological characters of the putative hybrids were found to be intermediate between those of R. humeana and R. cautleoides. Meanwhile, molecular analysis confirmed that the morphological intermediates were derived from hybridization between the two species. From the analysis of the NewHybrids, the hybridization individuals were mainly F₁s. These results indicated that interspecific hybridization between R. humeana and R. cautleoides indeed occurred in sympatric population.
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Affiliation(s)
- Guang-Hui Du
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun Town, Mengla County, Yunnan 666303, China
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Ma Y, Milne RI, Zhang C, Yang J. Unusual patterns of hybridization involving a narrow endemic Rhododendron species (Ericaceae) in Yunnan, China. AMERICAN JOURNAL OF BOTANY 2010; 97:1749-1757. [PMID: 21616807 DOI: 10.3732/ajb.1000018] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
PREMISE OF THE STUDY One potential threat to rare species is genetic swamping caused by hybridization, but few studies have quantified this threat. Rhododendron cyanocarpum is a narrow endemic species that occurs sympatrically with potentially interfertile congeners throughout its range within Yunnan, China. We searched the entire distribution of R. cyanocarpum for hybrids and examined the patterns of hybridization to assess potential threat from hybridization. • METHODS In a comprehensive field survey, we detected only one instance of hybridization involving R. cyanocarpum, with R. delavayi, at Huadianba near Dali. Material of both species and putative hybrids was examined using morphology, chloroplast DNA, nuclear ribosomal DNA, and Bayesian analysis of AFLP profiles. • KEY RESULTS Of 10 putative hybrids, two were F(1)(')s and at least seven were F(2)(')s. Four backcrosses to R. delavayi were detected among material with R. delavayi-like morphology within the hybrid zone. Backcrosses to R. cyanocarpum were not detected. Therefore F(2)(')s outnumbered all other classes within the hybrid zone, a situation not previously confirmed for plants and extremely rare generally. Hybridization was asymmetrical, with R. delavayi as the maternal parent in all but one of the hybrids detected. • CONCLUSIONS Although natural hybridization is common in Rhododendron, it is rare in R. cyanocarpum and is apparently not accompanied by backcrossing toward R. cyanocarpum. Hence, there is no immediate risk of genetic swamping, unless habitat disturbance increases and changes the patterns of hybridization. Our study is the first to report a plant hybrid zone dominated by F(2) hybrids. This pattern might contribute to species barrier maintenance.
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Affiliation(s)
- Yongpeng Ma
- Kunming Botanic Garden, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
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Ma YP, Zhang CQ, Zhang JL, Yang JB. Natural hybridization between Rhododendron delavayi and R. cyanocarpum (Ericaceae), from morphological, molecular and reproductive evidence. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2010; 52:844-851. [PMID: 20738728 DOI: 10.1111/j.1744-7909.2010.00970.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The natural hybridization that occurs between two sympatric species of Rhododendron subgenus Hymenanthes in Yunnan, China, was investigated. In field observations, it was noted that the putative hybrids between R. delavayi Franch. and R. cyanocarpum (Franch.) Franch. ex W.W. Sm. had intermediate morphologies. On the basis of morphology, chloroplast DNA (trnL-rpl32) and nuclear DNA (waxy), hybrids and parental species were identified. Hybridization occurred in both directions, but was asymmetrical, with R. delavayi as the major maternal parent. Reciprocal hand pollination treatments showed that either species, as pollen donor or pollen receiver, could produce fruits. It was noted that fruit set varied among treatments. The same pollinators (bumblebees) were shared in both parental species. From these results, we conclude that individuals with intermediate morphologies are indeed of hybrid origin from natural hybridization between R. cyanocarpum and R. delavayi. Furthermore, we presume the hybridization at the study site could have been initiated by habitat disturbance in the 1950s, and we may hence witness the early stages of hybrid swarm formation.
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Affiliation(s)
- Yong-Peng Ma
- Kunming Botanic Garden, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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Lo EYY. Testing hybridization hypotheses and evaluating the evolutionary potential of hybrids in mangrove plant species. J Evol Biol 2010; 23:2249-2261. [PMID: 20796134 DOI: 10.1111/j.1420-9101.2010.02087.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Natural hybridization is of marked importance from global to local biological diversity. In mangroves, species ranges overlap extensively with one another and species share a long overlap of flowering time. Although hybridization has been suggested, patterns of hybridization and the evolutionary potential of hybrids are not yet fully understood. This study provides molecular evidence for the parental origins and status of hybrids in the dominant mangrove genus Rhizophora based on comparisons of chloroplast and nuclear phylogenies and estimations of genetic relatedness and structure from inter-simple sequence repeat (ISSR) markers. Phylogenetic analyses indicate that almost all species can act as maternal parents to hybrids and that hybridization can be bidirectional. Bayesian analyses indicate that hybrids are simple F(1) s, and no trace of backcrossing was detected within populations. Hybridization, for the most part, occurs almost only locally and dispersal of hybrid individuals is limited beyond the hybrid sites.
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Affiliation(s)
- E Y Y Lo
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520, USA.
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