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Garlovsky MD, Whittington E, Albrecht T, Arenas-Castro H, Castillo DM, Keais GL, Larson EL, Moyle LC, Plakke M, Reifová R, Snook RR, Ålund M, Weber AAT. Synthesis and Scope of the Role of Postmating Prezygotic Isolation in Speciation. Cold Spring Harb Perspect Biol 2024; 16:a041429. [PMID: 38151330 PMCID: PMC11444258 DOI: 10.1101/cshperspect.a041429] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
How barriers to gene flow arise and are maintained are key questions in evolutionary biology. Speciation research has mainly focused on barriers that occur either before mating or after zygote formation. In comparison, postmating prezygotic (PMPZ) isolation-a barrier that acts after gamete release but before zygote formation-is less frequently investigated but may hold a unique role in generating biodiversity. Here we discuss the distinctive features of PMPZ isolation, including the primary drivers and molecular mechanisms underpinning PMPZ isolation. We then present the first comprehensive survey of PMPZ isolation research, revealing that it is a widespread form of prezygotic isolation across eukaryotes. The survey also exposes obstacles in studying PMPZ isolation, in part attributable to the challenges involved in directly measuring PMPZ isolation and uncovering its causal mechanisms. Finally, we identify outstanding knowledge gaps and provide recommendations for improving future research on PMPZ isolation. This will allow us to better understand the nature of this often-neglected reproductive barrier and its contribution to speciation.
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Affiliation(s)
- Martin D Garlovsky
- Applied Zoology, Faculty of Biology, Technische Universität Dresden, Dresden 01062, Germany
| | | | - Tomas Albrecht
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno 60365, Czech Republic
- Department of Zoology, Faculty of Science, Charles University, Prague 128 00, Czech Republic
| | - Henry Arenas-Castro
- School of Biological Sciences, University of Queensland, St Lucia 4072, Queensland, Australia
| | - Dean M Castillo
- Department of Biological Sciences, Miami University, Hamilton, Ohio 45011, USA
| | - Graeme L Keais
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Erica L Larson
- Department of Biological Sciences, University of Denver, Denver, Colorado 80208, USA
| | - Leonie C Moyle
- Department of Biology, Indiana University Bloomington, Indiana 47405, USA
| | - Melissa Plakke
- Division of Science, Mathematics, and Technology, Governors State University, University Park, Illinois 60484, USA
| | - Radka Reifová
- Department of Zoology, Faculty of Science, Charles University, Prague 128 00, Czech Republic
| | - Rhonda R Snook
- Department of Zoology, Stockholm University, Stockholm 109 61, Sweden
| | - Murielle Ålund
- Department of Ecology and Genetics, Animal Ecology, Uppsala University, Uppsala 75236, Sweden
| | - Alexandra A-T Weber
- Department of Aquatic Ecology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf 8600, Zürich, Switzerland
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2
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Munguía‐Rosas MA, Parra‐Tabla V, Rodríguez‐Domínguez JM. Partial and asymmetrical reproductive isolation between two sympatric tropical shrub species: Cnidoscolus aconitifolius and C. souzae (Euphorbiaceae). Ecol Evol 2023; 13:e10801. [PMID: 38089899 PMCID: PMC10714054 DOI: 10.1002/ece3.10801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 10/13/2023] [Accepted: 11/22/2023] [Indexed: 10/16/2024] Open
Abstract
Reproductive isolation is conferred by several barriers that occur at different stages of reproduction. Comprehensive reviews on the topic have identified that barriers occurring prior to zygote formation are often stronger than those that occur afterward. However, the overrepresentation of temperate perennial herbs in the current literature precludes any generalization of this pattern to plants that present other life forms and patterns of distribution. Here, we assessed reproductive isolation barriers and their absolute contribution to reproductive isolation and asymmetry in Cnidoscolus aconitifolius and C. souzae, two closely related tropical shrub species that co-occur on the Yucatan peninsula. The reproductive barriers assessed were phenological mismatch, pollinator differentiation, pollen-pistil incompatibility (three pre-zygotic barriers), fruit set failure, and seed unviability (post-zygotic barriers). Reproductive isolation between the study species was found to be complete in the direction C. aconitifolius to C. souzae, but only partial in the opposite direction. One post-zygotic barrier was the strongest example. Most barriers, particularly the pre-zygotic examples, were asymmetrical and predicted the direction of heterospecific pollen flow and hybrid formation from C. souzae to C. aconitifolius. Both parental species, as well as the hybrids, were diploid and had a chromosome number 2n = 36. More studies with tropical woody perennials are required to fully determine whether this group of plants consistently shows stronger post-zygotic barriers.
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Affiliation(s)
- Miguel A. Munguía‐Rosas
- Laboratorio de Ecología Terrestre, Departamento de Ecología HumanaCentro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav)MéridaMexico
| | - Víctor Parra‐Tabla
- Departamento de Ecología TropicalUniversidad Autónoma de YucatánMéridaMexico
| | - José M. Rodríguez‐Domínguez
- Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A.C. Unidad de Biotecnología VegetalGuadalajaraMexico
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3
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Tang J, Xiao Y, Xu X, Tang M, Zhang X, Yi Y. Root microbiota alters response to root rot in Rhododendron delavayi Franch. Front Microbiol 2023; 14:1236110. [PMID: 37692401 PMCID: PMC10486992 DOI: 10.3389/fmicb.2023.1236110] [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: 06/07/2023] [Accepted: 08/08/2023] [Indexed: 09/12/2023] Open
Abstract
Root microbiota have a significant effect on plant health. However, the role of root microbiota in the resistance of Rhododendron against root rot is not known. In this study, we employed amplicon 16S and ITS sequencing to investigate the bacterial and fungal communities associated with four distinct niches (bulk soil, rhizosphere, rhizoplane, and endosphere) of both healthy and diseased Rhododendron plants in the Baili Rhododendron nature reserve in China. The amplicon data analysis identified 182 bacterial genera and 141 fungal genera that were impacted by root rot across all niches. Specifically, the rhizoplane appeared to exert a selective gating effect, resulting in a reduction in the complexity of bacterial communities, but not fungal communities, in wild Rhododendron delavayi Franch roots. Nevertheless, the stress induced by root rot led to alterations in the root microbiota and compromised the gating function of the rhizoplane, thereby significantly increasing the complexity of the bacterial community within the plant root. In the root tissue following root rot outbreak, the relative abundance of the pathogenic species Pezicula brunnea and Diaporthe helianthi was enriched by as much as 6.13% and 1.71%, respectively. These findings provide novel insights into the contribution of enrichment of root-associated microbiota to wild plant hosts under the disease stress of root rot. The root rot-causing pathogenic fungi may interact with beneficial bacteria and induce plants to send out "cry for help" signals, which may encourage the specific assembly of microbiota. In the Rhododendron delavayi Franch root microbiota, we found 23 potentially beneficial microbes. Notably, certain beneficial bacteria, such as Sporolactobacillus and Stenotrophomonas, were found to accumulate in the rhizoplane and endosphere under root rot disease stress. Overall, our results lend support to our hypothesis that Rhododendron recruits protective microbes as a strategy to suppress root rot outbreaks. Future endeavors in isolating beneficial microbes capable of mitigating root rot have the potential to enhance plant resilience against root diseases.
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Affiliation(s)
- Jing Tang
- Key Laboratory of State Forestry Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, School of Life Sciences, Guizhou Normal University, Guiyang, China
| | - Yufeng Xiao
- State Key Laboratory of Plant Physiology and Development in Guizhou Province, Guizhou Normal University, Guiyang, China
| | - Xiaorong Xu
- State Key Laboratory of Plant Physiology and Development in Guizhou Province, Guizhou Normal University, Guiyang, China
| | - Ming Tang
- Key Laboratory of State Forestry Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, School of Life Sciences, Guizhou Normal University, Guiyang, China
| | - Ximin Zhang
- State Key Laboratory of Plant Physiology and Development in Guizhou Province, Guizhou Normal University, Guiyang, China
| | - Yin Yi
- Key Laboratory of State Forestry Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, School of Life Sciences, Guizhou Normal University, Guiyang, China
- State Key Laboratory of Plant Physiology and Development in Guizhou Province, Guizhou Normal University, Guiyang, China
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4
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Quan W, Wang A, Li C, Xie L. Allelopathic potential and allelochemical composition in different soil layers of Rhododendron delavayi forest, southwest China. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.963116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Forests habituated by Rhododendron delavayi often lack understory vegetation, which could possibly be a consequence of allelopathy. It is a phenomenon by virtue of which certain plant species produce allelochemicals that affect the growth and behavior of surrounding plants. To elucidate the allelopathic potential and allelochemicals present in the different layers of a R. delavayi forest, extracts obtained from three layers of the forest were used for seed germination bioassays and gas chromatography-mass spectrometry (GC–MS) analysis. Aqueous extracts of the litter and humus layers significantly inhibited the seed germination of R. delavayi, Festuca arundinacea, and Lolium perenne, with the litter layer causing the strongest inhibitory effect. A total of 26 allelochemicals were identified in the litter, humus, and soil layers by GC–MS analysis. The primary allelochemicals in the soil and humus layer were organic acids, while the main allelochemicals in the litter layer were phenolic acids. The redundancy analysis revealed the significance of total nitrogen (TN) and relative water content (RWC) in explaining the distribution of the allelochemicals. The results indicated that the litter layer exerted the maximum allelopathic effect due to presence of maximum amount of allelochemical especially the phenolic acids.
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5
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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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Microhabitat and Pollinator Differentiation Drive Reproductive Isolation between Two Sympatric Salvia Species (Lamiaceae). PLANTS 2022; 11:plants11182423. [PMID: 36145824 PMCID: PMC9506227 DOI: 10.3390/plants11182423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/05/2022] [Accepted: 09/13/2022] [Indexed: 11/16/2022]
Abstract
Evaluation of multiple barriers contributing to reproductive isolation between sympatric plant species is key to understanding the mechanism of their coexistence; however, such investigations in biodiversity hotspots are still rare. In this study, we investigated and compared geography, microhabitat, phenology, flora, and pollinators, in addition to pollen–pistil interactions, seed production, and seed germination of the closely related sympatric Salvia digitaloides and S. flava on Yulong Snow Mountain, Southwestern Yunnan, China. The geographic distribution of these species overlapped, but their adaptation to physical and chemical properties of soil microhabitats differed. They shared the same flowering time but differed in flower size, style length, nectar volume, sugar concentration, and flower longevity. Both species shared bumblebees as effective pollinators, but flower constancy for the two species was relatively strong. Pollen tube growth, seed production, and seed germination were lower in interspecific than in intraspecific crosses. Our study suggested that microhabitat and pollinator isolation acted as the most important isolating barriers in maintaining the coexistence of the two Salvia species. Our study also highlighted that post-pollination barriers play an important role in preventing the gene flow between these two Salvia species.
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Khan Z, Khan MS, Bawazeer S, Bawazeer N, Suleman, Irfan M, Rauf A, Su XH, Xing LX. A comprehensive review on the documented characteristics of four Reticulitermes termites (Rhinotermitidae, Blattodea) of China. BRAZ J BIOL 2022; 84:e256354. [PMID: 35319619 DOI: 10.1590/1519-6984.256354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 01/11/2022] [Indexed: 11/22/2022] Open
Abstract
Termites are known as social insects worldwide. Presently in China 473 species, 44 genera and 4 families of termites have been reported. Of them, 111 Reticulitermes species are widely spread in different zones of China. The dispersion flight season of these Chinese Reticulitermes species are usually started from February to June, but in some regions different species are distributed, sharing their boundaries and having overlapping flight seasons. These reasons become important sources of hybridization between two different heterospecific populations of termites. It was confirmed that the fertilized eggs and unfertilized eggs of some Reticulitermes termites have the capacity of cleavage. While the unfertilized eggs of R. aculabialis, R. chinensis and R. labralis cleaved normally and the only R. aculabialis unfertilized eggs develop in embryos. While, the R. flaviceps and R. chinensis were observed with their abnormal embryonic development, and not hatching of eggs parthenogenetically. They were reported more threatening to Chinese resources as they propagate with parthenogenesis, hybridization and sexual reproduction. Eggshell and macrophiles of eggs play important roles in species identification and control. Although, they are severe pests and cause a wide range of damages to wooden structures and products in homes, buildings, building materials, trees, crops, and forests in China's Mainland.
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Affiliation(s)
- Z Khan
- Northwest University, College of Life Sciences, Xi'an, China.,University of Swabi, Zoology Department, Khyber Pakhtunkhwa, Pakistan
| | - M S Khan
- University of Swabi, Zoology Department, Khyber Pakhtunkhwa, Pakistan
| | - S Bawazeer
- Umm Al-Qura University, Faculty of Pharmacy, Department of Pharmacognosy, Makkah, Kingdom of Saudi Arabia
| | - N Bawazeer
- Minister of Interior General Directorate of Prison's Health, Pharmacy Department, Kingdom of Saudi Arabia
| | - Suleman
- University of Swabi, Zoology Department, Khyber Pakhtunkhwa, Pakistan
| | - M Irfan
- Abdul Wali Khan University, Department of Botany, Mardan, Pakistan.,University of Swabi, Department of Botany, Swabi, Pakistan.,Missouri Botanical Garden, St. Louis, MO, U.S.A
| | - A Rauf
- University of Swabi, Department of Chemistry, Anbar, Khyber Pakhtunkhwa, Pakistan
| | - X-H Su
- Northwest University, College of Life Sciences, Xi'an, China.,Northwest University, Shaanxi Key Laboratory for Animal Conservation, Xi'an, China.,Northwest University, Key Laboratory of Resource Biology and Biotechnology, Xi'an, China
| | - L-X Xing
- Northwest University, College of Life Sciences, Xi'an, China.,Northwest University, Shaanxi Key Laboratory for Animal Conservation, Xi'an, China.,Northwest University, Key Laboratory of Resource Biology and Biotechnology, Xi'an, China
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8
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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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Ma H, Liu Y, Liu D, Sun W, Liu X, Wan Y, Zhang X, Zhang R, Yun Q, Wang J, Li Z, Ma Y. Chromosome-level genome assembly and population genetic analysis of a critically endangered rhododendron provide insights into its conservation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:1533-1545. [PMID: 34189793 DOI: 10.1111/tpj.15399] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 06/23/2021] [Indexed: 05/25/2023]
Abstract
Rhododendrons are woody plants, famous throughout the world as having high horticultural value. However, many wild species are currently threatened with extinction. Here, we report for the first time a high-quality, chromosome-level genome of Rhododendron griersonianum, which has contributed to approximately 10% of all horticultural rhododendron varieties but which in its wild form has been evaluated as critically endangered. The final genome assembly, which has a contig N50 size of approximately 34 M and a total length of 677 M, is the highest-quality genome sequenced within the genus to date, in part due to its low heterozygosity (0.18%). Identified repeats constitute approximately 57% of the genome, and 38 280 protein-coding genes were predicted with high support. We further resequenced 31 individuals of R. griersonianum as well as 30 individuals of its widespread relative R. delavayi, and performed additional conservation genomic analysis. The results showed that R. griersonianum had lower genetic diversity (θ = 2.58e-3; π = 1.94e-3) when compared not only to R. delavayi (θ = 11.61e-3, π = 12.97e-3), but also to most other woody plants. Furthermore, three severe genetic bottlenecks were detected using both the Stairway plot and fastsimcoal2 analysis, which are thought to have occurred in the late Middle Pleistocene and the Last Glacial Maximum (LGM) period. After these bottlenecks, R. griersonianum recovered and maintained a constant effective population size (>25 000) until now. Intriguingly, R. griersonianum has accumulated significantly more deleterious mutations in the homozygous state than R. delavayi, and several deleterious mutations (e.g., in genes involved in the response to heat stress) are likely to have harmed the adaptation of this plant to its surroundings. This high-quality, chromosome-level genome and the population genomic analysis of the critically endangered R. griersonianum will provide an invaluable resource as well as insights for future study in this species to facilitate conservation and in the genus Rhododendron in general.
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Affiliation(s)
- Hong Ma
- Research Institute of Resources Insects, Chinese Academy of Forestry, Kunming, 650233, China
| | - Yongbo Liu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, 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, 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, Kunming, 650201, China
| | - Xiongfang Liu
- Research Institute of Resources Insects, Chinese Academy of Forestry, Kunming, 650233, China
| | - Youming Wan
- Research Institute of Resources Insects, Chinese Academy of Forestry, Kunming, 650233, China
| | - Xiujiao Zhang
- Research Institute of Resources Insects, Chinese Academy of Forestry, Kunming, 650233, China
| | - Rengang Zhang
- Beijing Ori-Gene Science and Technology Co. Ltd, Beijing, 102206, China
| | - Quanzheng Yun
- Beijing Ori-Gene Science and Technology Co. Ltd, Beijing, 102206, China
| | - Jihua Wang
- The Flower Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, 650205, China
- National Engineering Research Center for Ornamental Horticulture, Kunming, 650205, China
| | - Zhenghong Li
- Research Institute of Resources Insects, Chinese Academy of Forestry, Kunming, 650233, 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, 650201, China
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10
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Liu D, Zhang L, Wang J, Ma Y. Conservation Genomics of a Threatened Rhododendron: Contrasting Patterns of Population Structure Revealed From Neutral and Selected SNPs. Front Genet 2020; 11:757. [PMID: 33101354 PMCID: PMC7500208 DOI: 10.3389/fgene.2020.00757] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 06/25/2020] [Indexed: 12/13/2022] Open
Abstract
Though it is well-acknowledged that next generation sequencing (NGS) technologies can provide further insights into plant conservation management than traditional molecular markers, studies employing NGS to address conservation genomics and subsequent conservation strategies for threatened plants are still rare. Rhododendron is the largest genus of woody plants in China, and many species are threatened, however, to date there has been no conservation genetic research using NGS in this genus. In the present study, we investigated the conservation genetics of R. cyanocarpum, a threatened species endemic to the Cangshan Mountains in Yunnan, China, using a double digest restriction-site-associated DNA-sequencing (ddRAD-seq) approach. Due to the availability of sufficient SNPs, we were able to distinguish between neutral and putatively selected SNPs and were able to further investigate the genetic diversity, population structure, and differentiation in R. cyanocarpum, as well as make an estimation of its demographic history. A total of 6,584 SNPs were obtained, of which 5,729 were neutral (detected using Tajima’s D). In terms of the 5,729 neutral SNPs, R. cyanocarpum had a higher genetic diversity (π = 0.0702 ± 0.0017, He = 0.0675 ± 0.0016) than other plant species assessed using Rad-seq methods, while population differentiation (Fst from 0.0314 to 0.0452) was weak. Interestingly, contrasting patterns of population structure were revealed from all neutral and selected SNPs, with distinct genetic clusters forming for all SNPs and neutral SNPs, but no distinct subgroups for selected ones. Moreover, we were able to detect changes in effective population size (Ne) of R. cyanocarpum from 150,000 years ago, including a bottleneck event ca. 60,000 years ago, followed by recovery of Ne over a short period, and a subsequent gradual decline in Ne to date. Implications for conserving R. cyanocarpum based on these main results are then discussed.
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Affiliation(s)
- 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
| | - Lu Zhang
- Flower Research Institute, Yunnan Academy of Agriculture Sciences, Kunming, China
| | - Jihua Wang
- Flower Research Institute, Yunnan Academy of Agriculture Sciences, Kunming, 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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11
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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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12
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Yang B, Zhang G, Guo F, Wang M, Wang H, Xiao H. A Genomewide Scan for Genetic Structure and Demographic History of Two Closely Related Species, Rhododendron dauricum and R. mucronulatum ( Rhododendron, Ericaceae). FRONTIERS IN PLANT SCIENCE 2020; 11:1093. [PMID: 32765570 PMCID: PMC7380098 DOI: 10.3389/fpls.2020.01093] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
Understanding the processes of divergence and speciation is an important task for evolutionary research, and climate oscillations play a pivotal role. We estimated the genetic structure and demographic history of two closely related species of Rhododendron, R. dauricum, and R. mucronulatum, distributed in northeastern China using 664,406 single nucleotide polymorphic loci of specific-locus amplified fragment sequencing (SLAF-seq) and 4 chloroplast DNA (cpDNA) fragments, sampling 376 individuals from 39 populations of these two species across their geographic distributions. The geographical distribution of cpDNA haplotypes revealed that R. dauricum and R. mucronulatum have different spatial genetic structures and haplotype diversity. Analysis of molecular variance (AMOVA) results showed that these two species have significant genetic differentiation and that the phylogeny demonstrates that these two species clustered a monophyletic group based on SLAF data, respectively, but not in cpDNA data. The evidence of significant gene flow was also detected from R. mucronulatum to R. dauricum. A deep divergence between the two species was observed and occurred during the early Oligocene. The niche models showed that the two species have different demographic histories. Thus, our results imply that geography and climate changes played important roles in the evolutionary process of R. dauricum and R. mucronulatum, and although there was an interspecific gene flow, the divergence was maintained by natural selection.
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Affiliation(s)
- Baiming Yang
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China
- Changchun Guoxin Modern Agricultural Technology Development Co., Ltd., Changchun, China
| | - Guoli Zhang
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China
| | - Fengping Guo
- Biology Group, No. 30 Middle School of Shenyang, Shenyang, China
| | - Manqi Wang
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China
| | - Huaying Wang
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China
| | - Hongxing Xiao
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China
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13
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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: 18] [Impact Index Per Article: 3.6] [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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14
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Ma Y, Marczewski T, Xue D, Wu Z, Liao R, Sun W, Marczewski J. Conservation implications of asymmetric introgression and reproductive barriers in a rare primrose species. BMC PLANT BIOLOGY 2019; 19:286. [PMID: 31253088 PMCID: PMC6599365 DOI: 10.1186/s12870-019-1881-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 06/10/2019] [Indexed: 05/23/2023]
Abstract
BACKGROUND Primula is a large genus of flowering herbs well known for their heterostyly. Currently few natural hybrids are known and reproductive barriers in this genus in the wild have received little attention. However, there is instance of hybridization between rare and widely-spread species, and conservation implications of such situation is poorly understood. In the present study, we investigated hybridization patterns and reproductive barriers between a wide spread species, Primula poissonii and a rare species P. anisodora, of which only three populations are currently known. RESULTS Pollinator-mediated reproductive isolation was strong between parental species but not significant between hybrids and parental species. Hand pollination experiments showed significant reduction of both fruit- and seed-set for heterospecific pollination as compared with conspecific pollination for both parental species. Furthermore, hybrids had higher fruit- and seed-set when pollinated with P. anisodora pollen as opposed to P. poissonii pollen. Microsatellites identified backcrosses to P. anisodora in two of the three populations of P. anisodora, and additionally more individuals of P. anisodora showed introgression from P. poissonii than vice versa. CONCLUSIONS These results provide evidence for potential genetic swamping of the P. anisodora populations, which could pose a serious threat for this locally endemic species.
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Affiliation(s)
- Yongpeng Ma
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Kunming, 650201 Yunnan China
| | - Tobias Marczewski
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Kunming, 650201 Yunnan China
| | - Dan Xue
- Yunnan Agricultural University, Kunming, 650201 Yunnan China
| | - Zhikun Wu
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Kunming, 650201 Yunnan China
| | - Rongli Liao
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Kunming, 650201 Yunnan China
| | - Weibang Sun
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Kunming, 650201 Yunnan China
| | - Jane Marczewski
- Yunnan Agricultural University, Kunming, 650201 Yunnan China
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15
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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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16
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Esposito F, Vereecken NJ, Gammella M, Rinaldi R, Laurent P, Tyteca D. Characterization of sympatric Platanthera bifolia and Platanthera chlorantha (Orchidaceae) populations with intermediate plants. PeerJ 2018; 6:e4256. [PMID: 29379684 PMCID: PMC5787349 DOI: 10.7717/peerj.4256] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/20/2017] [Indexed: 12/25/2022] Open
Abstract
Platanthera bifolia and P. chlorantha are terrestrial and rewarding orchids with a wide Eurasian distribution. Although genetically closely related, they exhibit significant morphological, phenological and ecological differences that maintain reproductive isolation between the species. However, where both species co-occur, individuals with intermediate phenotypic traits, often considered as hybrids, are frequently observed. Here, we combined neutral genetic markers (AFLPs), morphometrics and floral scent analysis (GC-MS) to investigate two mixed Platanthera populations where morphologically intermediate plants were found. Self-pollination experiments revealed a low level of autogamy and artificial crossings combined with assessments of fruit set and seed viability, showed compatibility between the two species. The results of the genetic analyses showed that morphologically intermediate plants had similar genetic patterns as the P. bifolia group. These results are corroborated also by floral scent analyses, which confirmed a strong similarity in floral scent composition between intermediate morphotypes and P. bifolia. Therefore, this study provided a much more detailed picture of the genetic structure of a sympatric zone between two closely allied species and supports the hypothesis that intermediate morphotypes in sympatry could reflect an adaptive evolution in response to local pollinator-mediated selection.
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Affiliation(s)
- Fabiana Esposito
- Earth and Life Institute—Biodiversity Research Centre, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Nicolas J. Vereecken
- Agroecology Lab, Brussels Bioengineering School, Université libre de Bruxelles (ULB), Brussels, Belgium
| | | | - Rosita Rinaldi
- Department of Biology, University of Naples Federico II, Napoli, Italy
| | - Pascal Laurent
- Unit of General Chemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Daniel Tyteca
- Earth and Life Institute—Biodiversity Research Centre, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
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17
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Li T, Liu X, Li Z, Ma H, Wan Y, Liu X, Fu L. Study on Reproductive Biology of Rhododendron longipedicellatum: A Newly Discovered and Special Threatened Plant Surviving in Limestone Habitat in Southeast Yunnan, China. FRONTIERS IN PLANT SCIENCE 2018; 9:33. [PMID: 29445383 PMCID: PMC5797782 DOI: 10.3389/fpls.2018.00033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 01/09/2018] [Indexed: 05/03/2023]
Abstract
Rhododendron longipedicellatum is a narrow endemic species and a subject of urgent demand in the domestic market and overseas. Its fascinating shapes, brilliantly gilvous flowers, and unusual flowering time endow this species with extremely high ornamental value. However, only five wild populations of R. longipedicellatum surviving in limestone habitat have been found through elaborate field investigation, and the number of the populations decreases further or is even confronted with risk of extinction due to the damage of human activities. To enhance the protection and utilization of R. longipedicellatum, this study systematically investigated several important aspects of reproductive biology, including floral syndrome, pollen viability and stigma receptivity, petal color reflectance, breeding system, and pollination biology. The results demonstrated that arched styles not only create obvious herkogamy that avoide self-pollination, but also effectively reduce rain damage to the intrinsic characteristics of the stigma surface secretions, promoting the female fitness of R. longipedicellatum in poor weather. Pollen viability maintained a high level over the flowering period. The reflectance spectrum of petals had two peaks at wavelengths of 360 and 580 nm. Tests of OCI, P/O and artificial pollination all indicated that R. longipedicellatum was self-compatible and that the breeding system was mixed mating. Geitonogamy mediated by Bombus braccatus was the primary pollination route in the natural environment, which suggested that the breeding system of R. longipedicellatum might be evolving from selfing to outcrossing. The pollination vector of R. longipedicellatum was very specific, in that only B. braccatus was confirmed to deliver pollen to the stigmas. Visitation frequency was influenced by the activity rhythms and resource requirements of the different castes (i.e., sex). B. braccatus workers were the most effective pollinators because of higher visitation frequency and more effective contribution to fruit production, whereas the presence of B. braccatus males might enhance pollen flow within the population to a certain extent. Finally, these findings not only provided a reliable theoretical basis for hybridization breeding of R. longipedicellatum as parents, but also laid a solid foundation for further molecular biology studies to more broadly reveal the mechanisms of its endangerment in the future.
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Affiliation(s)
- Taiqiang Li
- Research Institute of Resource Insects, Chinese Academy of Forestry, Kunming, China
| | - Xiongfang Liu
- Research Institute of Resource Insects, Chinese Academy of Forestry, Kunming, China
| | - Zhenghong Li
- Research Institute of Resource Insects, Chinese Academy of Forestry, Kunming, China
| | - Hong Ma
- Research Institute of Resource Insects, Chinese Academy of Forestry, Kunming, China
- *Correspondence: Hong Ma, Liyong Fu,
| | - Youming Wan
- Research Institute of Resource Insects, Chinese Academy of Forestry, Kunming, China
| | - Xiuxian Liu
- Research Institute of Resource Insects, Chinese Academy of Forestry, Kunming, China
| | - Liyong Fu
- Research Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing, China
- *Correspondence: Hong Ma, Liyong Fu,
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18
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Zhang W, Gao J. Multiple factors contribute to reproductive isolation between two co-existing Habenaria species (Orchidaceae). PLoS One 2017; 12:e0188594. [PMID: 29176771 PMCID: PMC5703478 DOI: 10.1371/journal.pone.0188594] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 11/09/2017] [Indexed: 11/21/2022] Open
Abstract
Reproductive isolation is a key feature that forms barriers to gene flow between distinct plants. In orchids, prezygotic reproductive isolation has been considered to be strong, because their associations with highly specific pollinators. In this study, the reproductive ecology and reproductive isolation of two sympatric Habenaria species, H. davidii and H. fordii, was investigated by floral phenology and morphology, hand-pollination experiments and visitor observation in southwest China. The two species were dependent on insects for pollination and completely self-compatible. A number of factors have been identified to limit gene flow between the two species and achieved full reproductive isolation. Ecogeographic isolation was a weak barrier. H. fordii and H. davidii had completely overlapped flowering periods, and floral morphology plays an important role in floral isolation. The two species shared the same hawkmoth pollinator, Cechenena lineosa, but the pollinaria of the two orchids were attached on different body parts of pollinators. Prezygotic isolation was not complete, but the interspecific pollination treatments of each species resulted in no seed sets, indicating that unlike many other orchid species, in which the postzygotic reproductive isolation is very weak or complete absence, the post-zygotic isolation strongly acted in the stage of seed production between two species. The results illustrate the reproductive isolation between two species involves multiple plant life-history stages and a variety of reproductive barriers can contribute to overall isolation.
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Affiliation(s)
- Wenliu Zhang
- Centre for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jiangyun Gao
- Laboratory of Ecology and Evolutionary Biology, State Key Laboratory for Conservation and Utilization of Bio-resources in Yunnan, Yunnan University, Kunming, Yunnan, China
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19
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Xie Y, Zhu X, Ma Y, Zhao J, Li L, Li Q. Natural hybridization and reproductive isolation between two Primula species. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2017; 59:526-530. [PMID: 28429397 DOI: 10.1111/jipb.12546] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 04/17/2017] [Indexed: 06/07/2023]
Abstract
Natural hybridization frequently occurs in plants and can facilitate gene flow between species, possibly resulting in species refusion. However, various reproductive barriers block the formation of hybrids and maintain species integrity. Here, we conducted a field survey to examine natural hybridization and reproductive isolation (RI) between sympatric populations of Primula secundiflora and P. poissonii using ten nuclear simple sequence repeat (SSR) loci. Although introgressive hybridization occurred, species boundaries between P. secundiflora and P. poissonii were maintained through nearly complete reproductive isolation. These interfertile species provide an excellent model for studying the RI mechanisms and evolutionary forces that maintain species boundaries.
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Affiliation(s)
- Yanping Xie
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China
- Graduate University of Chinese Academy of Sciences, Beijing 10049, China
| | - Xingfu Zhu
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China
| | - Yongpeng Ma
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Jianli Zhao
- Laboratory of Ecology and Evolutionary Biology, State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650091, China
| | - Li Li
- Graduate University of Chinese Academy of Sciences, Beijing 10049, China
| | - Qingjun Li
- Laboratory of Ecology and Evolutionary Biology, State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650091, China
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20
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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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21
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A hybridisation barrier between two evolutionary lineages of Barbarea vulgaris (Brassicaceae) that differ in biotic resistances. Evol Ecol 2016. [DOI: 10.1007/s10682-016-9858-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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22
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Ma Y, Zhou R, Milne R. Pollinator-Mediated Isolation May Be an Underestimated Factor in Promoting Homoploid Hybrid Speciation. FRONTIERS IN PLANT SCIENCE 2016; 7:1183. [PMID: 27540392 PMCID: PMC4972831 DOI: 10.3389/fpls.2016.01183] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 07/22/2016] [Indexed: 05/31/2023]
Affiliation(s)
- Yongpeng Ma
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
| | - Renchao Zhou
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, Sun Yat-sen UniversityGuangzhou, China
| | - Richard Milne
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of EdinburghEdinburgh, UK
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