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Suetsugu K, Hirota SK, Shitara T, Ishida K, Nakato N, Hayakawa H, Suyama Y. The absence of bumblebees on an oceanic island blurs the species boundary of two closely related orchids. THE NEW PHYTOLOGIST 2024; 241:1321-1333. [PMID: 37847353 DOI: 10.1111/nph.19325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/26/2023] [Indexed: 10/18/2023]
Abstract
Oceanic islands offer valuable natural laboratories for studying evolution. The Izu Islands, with their recent geological origin, provide an exceptional opportunity to explore the initial evolution on oceanic islands. Another noteworthy aspect is the absence of bumblebee species on most Izu Islands. We used ecological, morphological, and molecular data to investigate the impact of bumblebee absence on the evolution of two closely related orchid species, Goodyera henryi and Goodyera similis, focusing on Kozu Island, the Izu Islands. Our investigation revealed that while G. henryi exclusively relies on a bumblebee species for pollination on the mainland, G. similis is pollinated by scoliid wasps on both the mainland and the island. Intriguingly, all specimens initially categorized as G. henryi on Kozu Island are hybrids of G. henryi and G. similis, leading to the absence of pure G. henryi distribution on the island. These hybrids are pollinated by the scoliid wasp species that also pollinates G. similis on the island. The absence of bumblebees might result in sporadic and inefficient pollination of G. henryi by scoliid wasps, consequently promoting hybrid proliferation on the island. Our findings suggest that the absence of bumblebees can blur plant species boundaries.
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Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Hyogo, 657-8501, Japan
- Institute for Advanced Research, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Shun K Hirota
- Field Science Center, Graduate School of Agricultural Science, Tohoku University, 232-3 Yomogida, Naruko-onsen, Osaki, Miyagi, 989-6711, Japan
- Botanical Gardens, Osaka Metropolitan University, 2000 Kisaichi, Katano City, Osaka, 576-0004, Japan
| | - Takuto Shitara
- Tama Forest Science Garden, Forestry and Forest Products Research Institute, 1833-81 Todori-machi, Hachioji, Tokyo, 193-0843, Japan
| | | | - Narumi Nakato
- Narahashi 1-363, Higashiyamato-shi, Tokyo, 207-0031, Japan
| | - Hiroshi Hayakawa
- Museum of Natural and Environmental History, Shizuoka, 5762 Oya, Suruga, Shizuoka, Shizuoka, 422-8017, Japan
| | - Yoshihisa Suyama
- Field Science Center, Graduate School of Agricultural Science, Tohoku University, 232-3 Yomogida, Naruko-onsen, Osaki, Miyagi, 989-6711, Japan
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2
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Hu L, Tate JA, Gardiner SE, MacKay M. Ploidy variation in Rhododendron subsection Maddenia and its implications for conservation. AOB PLANTS 2023; 15:plad016. [PMID: 37197711 PMCID: PMC10184449 DOI: 10.1093/aobpla/plad016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 04/06/2023] [Indexed: 05/19/2023]
Abstract
Polyploidy, which is common in plants, can confound taxon recognition and hence conservation assessments. In the taxonomically complex genus Rhododendron, 25 % of the over 1,300 taxa are considered under threat and 27 % Near Threatened or Data Deficient, with their taxonomy needing to be resolved urgently. Although ploidy levels of Rhododendron taxa range from diploid (2x) to dodecaploid (12x) according to previous reports, the extent of polyploidy across the genus has not been examined. We first summarized the taxonomic distribution of polyploids in the genus based on the literature. Then as a case study, we estimated ploidy levels of 47 taxa in subsection Maddenia (subgenus Rhododendron, section Rhododendron) using flow cytometry, together with verification of meiotic chromosome counts for representative taxa. The summary of reported ploidy in Rhododendron indicates that polyploidy is most common in subgenera Pentanthera and Rhododendron. In subsection Maddenia, all examined taxa are diploids except for the R. maddenii complex that shows a high ploidy variation (2-8x, 12x). We investigated ploidy level of 12 taxa in subsection Maddenia for the first time, and estimated genome sizes of two Rhododendron species. Knowledge of ploidy levels will inform phylogenetic analysis of unresolved species complexes. Overall, our study of subsection Maddenia provides a model for examining multiple issues including taxonomic complexity, ploidy variation and geographic distribution in relation to biodiversity conservation.
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Affiliation(s)
- Ling Hu
- Corresponding author’s e-mail address:
| | - Jennifer A Tate
- School of Natural Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Susan E Gardiner
- The New Zealand Institute for Plant and Food Research Limited, Fitzherbert Science Centre, Palmerston North 4472, New Zealand
| | - Marion MacKay
- School of Agriculture and Environment, Massey University, Palmerston North 4442, New Zealand
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3
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Jia YH, He F, Shen ZL, Xie XH, Lv SJ, Jiang BX, Yang GX, Yan YC, Wu ZH, Wu YY. Molecular characterization of a chalcone synthase gene RhCHS from Rhododendron × hybridum Hort. Gene X 2023; 857:147176. [PMID: 36627095 DOI: 10.1016/j.gene.2023.147176] [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: 04/27/2022] [Revised: 12/11/2022] [Accepted: 01/04/2023] [Indexed: 01/09/2023] Open
Abstract
Chalcone synthase (CHS) plays a vital role in anthocyanin biosynthesis pathway, which is associated with petal color of flower. To date, lots of CHS genes have been obtained from plants, while few were from Rhododendron genus. In this study we got a new CHS gene named RhCHS (MW358095) from Rhododendron × hybridum Hort. It had a 2040 bp coding region consisting of two exons and one intron. By using the deduced RhCHS protein as a query sequence, 15 CHS homologous family genes with sequence similarity from 60% to 98%, designated as RgCHS-D(x), were retrieved from the genome assembly of Rhododendron griersonianum (RGv1.1) by TBlastN. 12 CHS family genes were found locating in No.9 chromosome arranged in clusters, while only 3 of them exhibited in No.1, 2, and 8 chromosomes, respectively. The results revealed gene duplication of CHS in evolutionary process. Multiple alignment of the deduced amino acid sequence of RhCHS showed high similarity of the active site, the catalytic residue, and the signature motif, the conserved characteristics of which were also exhibited in the tertiary structure prediction of the RhCHS, as well as the phylogenetic tree, all these demonstrated the RhCHS belonging to the type III PKS superfamily. HPLC-MS/MS of flower petals detected the total concentration of CC, DC, and PelC. These anthocyanidins showed an overall increasing trend during the flowering period and reached the peak in the full-blooming stage, which was consistence with the changeable rule of RhCHS expression level. The promoter, which was 1507 bp exhibiting high β-glucuronidase (GUS) staining activity, was predicted containing many cis-acting elements, especially light and transcription factor such as bHLH, MYB, WRKY, Dof, and ERF. In short, this study may provide the help to Rhododendron × hybridum Hort. not only in the mechanism research of petals color exhibition, but also in molecular breeding of CHS practice value.
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Affiliation(s)
- Yong-Hong Jia
- College of Biological & Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China
| | - Fan He
- College of Biological & Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China
| | - Zi-Li Shen
- College of Biological & Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China
| | - Xiao-Hong Xie
- College of Biological & Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China
| | - Si-Jia Lv
- College of Biological & Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China
| | - Bao-Xin Jiang
- College of Biological & Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China
| | - Guo-Xia Yang
- College of Biological & Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China
| | - Yi-Cheng Yan
- College of Biological & Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China
| | - Ze-Hang Wu
- College of Biological & Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China
| | - Yue-Yan Wu
- College of Biological & Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China.
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4
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Zhang L, Huang YW, Huang JL, Ya JD, Zhe MQ, Zeng CX, Zhang ZR, Zhang SB, Li DZ, Li HT, Yang JB. DNA barcoding of Cymbidium by genome skimming: Call for next-generation nuclear barcodes. Mol Ecol Resour 2023; 23:424-439. [PMID: 36219539 DOI: 10.1111/1755-0998.13719] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/23/2022] [Accepted: 09/29/2022] [Indexed: 01/04/2023]
Abstract
Cymbidium is an orchid genus that has undergone rapid radiation and has high ornamental, economic, ecological and cultural importance, but its classification based on morphology is controversial. The plastid genome (plastome), as an extension of plant standard DNA barcodes, has been widely used as a potential molecular marker for identifying recently diverged species or complicated plant groups. In this study, we newly generated 237 plastomes of 50 species (at least two individuals per species) by genome skimming, covering 71.4% of members of the genus Cymbidium. Sequence-based analyses (barcoding gaps and automatic barcode gap discovery) and tree-based analyses (maximum likelihood, Bayesian inference and multirate Poisson tree processes model) were conducted for species identification of Cymbidium. Our work provides a comprehensive DNA barcode reference library for Cymbidium species identification. The results show that compared with standard DNA barcodes (rbcL + matK) as well as the plastid trnH-psbA, the species identification rate of the plastome increased moderately from 58% to 68%. At the same time, we propose an optimized identification strategy for Cymbidium species. The plastome cannot completely resolve the species identification of Cymbidium, the main reasons being incomplete lineage sorting, artificial cultivation, natural hybridization and chloroplast capture. To further explore the potential use of nuclear data in identifying species, the Skmer method was adopted and the identification rate increased to 72%. It appears that nuclear genome data have a vital role in species identification and are expected to be used as next-generation nuclear barcodes.
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Affiliation(s)
- Le Zhang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Yi-Wei Huang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, China
| | | | - Ji-Dong Ya
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Meng-Qing Zhe
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Chun-Xia Zeng
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Zhi-Rong Zhang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Shi-Bao Zhang
- Key Laboratory for Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - De-Zhu Li
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Hong-Tao Li
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Jun-Bo Yang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
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5
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Tian XL, Ma YP. Horticultural applications of natural hybrids as an accelerating way for breeding woody ornamental plants. Front Genet 2022; 13:1047100. [DOI: 10.3389/fgene.2022.1047100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 10/26/2022] [Indexed: 11/11/2022] Open
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6
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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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7
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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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8
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Hu L, Yang R, Wang YH, Gong X. The natural hybridization between species Ligularia nelumbifolia and Cremanthodium stenoglossum (Senecioneae, Asteraceae) suggests underdeveloped reproductive isolation and ambiguous intergeneric boundary. AOB PLANTS 2021; 13:plab012. [PMID: 33796247 PMCID: PMC7994929 DOI: 10.1093/aobpla/plab012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Natural hybridization is frequent in plants and is considered an important factor facilitating speciation. The natural intergeneric hybridization between Ligularia and Cremanthodium was previously confirmed using a couple of DNA markers. However, the mechanism of this intergeneric hybridization and the role of reproductive isolation in the process of hybridization remain unclear. Here we used double-digest restriction site-associated DNA sequencing (ddRAD-seq) to further quantify the occurrence of hybridization, the genetic structure of the hybrid population and the role of reproductive isolation between Ligularia nelumbifolia and Cremanthodium stenoglossum. The results based on the ddRAD-seq SNP data sets indicated that hybridization between L. nelumbifolia and C. stenoglossum was restricted to F1s, and no gene introgression was identified between these two species. STRUCTURE analysis and maximum likelihood (ML) tree results showed a slightly larger genetic contribution of L. nelumbifolia to putative hybrid F1s. We deduced that the reproductive isolation between these two parent species is not well-developed but still strong enough to maintain the genetic integrity of the species, and that their F1s are sterile or with low fertility. Given the poorly resolved phylogenetic relationship between Ligularia and Cremanthodium, the occurrence of natural hybridization between L. nelumbifolia and C. stenoglossum may provide new insights into the re-circumscription and re-delimitation of these two genera.
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Affiliation(s)
- Li Hu
- Plant Science Institute, School of Life Sciences, Yunnan University, Kunming 650201, Yunnan, China
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rui Yang
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yue-Hua Wang
- Plant Science Institute, School of Life Sciences, Yunnan University, Kunming 650201, Yunnan, China
| | - Xun Gong
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
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9
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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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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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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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Cross-transferability of SSR markers developed in Rhododendron species of Himalaya. Mol Biol Rep 2020; 47:6399-6406. [PMID: 32623614 DOI: 10.1007/s11033-020-05606-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/20/2020] [Indexed: 12/22/2022]
Abstract
Rhododendron is a genus of evergreen woody ornamental plants of northern hemisphere with strong cold resistance, attractive flowers and high altitude adaptation capacity. The genus originated and diversified from Sino-Himalayan region and spread across the world, and has high species diversity in Northeast India. To assess cross-species amplification, we tested 32 microsatellites markers in fifteen taxa of the genus Rhododendron of North-eastern Himalaya, of which fourteen microsatellites were newly developed from Rhododendron simsii, and eighteen microsatellites were previously developed from Rhododendron catawbiense and Rhododendron mucronatum var. ripense. Nine pairs of primers were amplified successfully in all species, however, none of them was failed for amplification in any of the species. The average observed heterozygosity, expected heterozygosity and PIC value were recorded as 0.310, 0.433 and 0.379 respectively. Clustering based on neighbour-joining analysis revealed the potential of these markers to segregate species according to their subgenus level, however, subspecies exhibited closeness with each other. Cross-application of these microsatellite loci will provide a potentially useful tool to investigate the genetic diversity, population structure, gene flow, phylogenetics and evolutionary relationships in species of genus Rhododendron.
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13
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Dai XY, Yang CH, Yang B, Chen P, Ma YP. A new species of Rhododendron (Ericaceae) from Guizhou, China. PHYTOKEYS 2020; 146:53-59. [PMID: 36760833 PMCID: PMC9849097 DOI: 10.3897/phytokeys.146.51342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 03/25/2020] [Indexed: 06/18/2023]
Abstract
A new species of the Rhododendron (Ericaceae) in subgen. Tsutsusisect.Tsutsusi from Puding county of Guizhou, China, is described and illustrated. The new species, R.pudingense X.Y. Dai, C.H. Yang & Y.P. Ma, is similar to R.myrsinifolium Ching ex Fang et M. Y. He and R.minutiflorum Hu, but it can be easily distinguished by its length and being pubescent on inner surface of corolla tube, sparse hairs below the middle of filament and the glabrous style.
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Affiliation(s)
- Xiao-Yong Dai
- Guizhou Academy of Forestry, Guiyang 550009, Guizhou, ChinaGuizhou Academy of ForestryGuiyangChina
| | - Cheng-Hua Yang
- Guizhou Academy of Forestry, Guiyang 550009, Guizhou, ChinaGuizhou Academy of ForestryGuiyangChina
| | - Bing Yang
- Guizhou Academy of Forestry, Guiyang 550009, Guizhou, ChinaGuizhou Academy of ForestryGuiyangChina
| | - Pu Chen
- Puding Forestry and Grassland Administration, Puding 562100, Guizhou, ChinaPuding Forestry and Grassland AdministrationPudingChina
| | - Yong-Peng Ma
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, ChinaKunming Institute of Botany, Chinese Academy of SciencesKunmingChina
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Soza VL, Lindsley D, Waalkes A, Ramage E, Patwardhan RP, Burton JN, Adey A, Kumar A, Qiu R, Shendure J, Hall B. The Rhododendron Genome and Chromosomal Organization Provide Insight into Shared Whole-Genome Duplications across the Heath Family (Ericaceae). Genome Biol Evol 2019; 11:3353-3371. [PMID: 31702783 PMCID: PMC6907397 DOI: 10.1093/gbe/evz245] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2019] [Indexed: 02/06/2023] Open
Abstract
The genus Rhododendron (Ericaceae), which includes horticulturally important plants such as azaleas, is a highly diverse and widely distributed genus of >1,000 species. Here, we report the chromosome-scale de novo assembly and genome annotation of Rhododendron williamsianum as a basis for continued study of this large genus. We created multiple short fragment genomic libraries, which were assembled using ALLPATHS-LG. This was followed by contiguity preserving transposase sequencing (CPT-seq) and fragScaff scaffolding of a large fragment library, which improved the assembly by decreasing the number of scaffolds and increasing scaffold length. Chromosome-scale scaffolding was performed by proximity-guided assembly (LACHESIS) using chromatin conformation capture (Hi-C) data. Chromosome-scale scaffolding was further refined and linkage groups defined by restriction-site associated DNA (RAD) sequencing of the parents and progeny of a genetic cross. The resulting linkage map confirmed the LACHESIS clustering and ordering of scaffolds onto chromosomes and rectified large-scale inversions. Assessments of the R. williamsianum genome assembly and gene annotation estimate them to be 89% and 79% complete, respectively. Predicted coding sequences from genome annotation were used in syntenic analyses and for generating age distributions of synonymous substitutions/site between paralgous gene pairs, which identified whole-genome duplications (WGDs) in R. williamsianum. We then analyzed other publicly available Ericaceae genomes for shared WGDs. Based on our spatial and temporal analyses of paralogous gene pairs, we find evidence for two shared, ancient WGDs in Rhododendron and Vaccinium (cranberry/blueberry) members that predate the Ericaceae family and, in one case, the Ericales order.
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Affiliation(s)
- Valerie L Soza
- Department of Biology, University of Washington, Seattle, WA
| | - Dale Lindsley
- Department of Biology, University of Washington, Seattle, WA
- Retired
| | - Adam Waalkes
- Department of Biology, University of Washington, Seattle, WA
- Department of Laboratory Medicine, University of Washington, Seattle, WA
| | | | | | - Joshua N Burton
- Department of Genome Sciences, University of Washington, Seattle, WA
- Adaptive Biotechnologies, Seattle, WA
| | - Andrew Adey
- Department of Genome Sciences, University of Washington, Seattle, WA
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR
| | - Akash Kumar
- Department of Genome Sciences, University of Washington, Seattle, WA
- Department of Pediatrics, Stanford University, Palo Alto, CA
| | - Ruolan Qiu
- Department of Genome Sciences, University of Washington, Seattle, WA
- Retired
| | - Jay Shendure
- Department of Genome Sciences, University of Washington, Seattle, WA
- Brotman Baty Institute for Precision Medicine, Seattle, WA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA
| | - Benjamin Hall
- Department of Biology, University of Washington, Seattle, WA
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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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16
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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: 3] [Impact Index Per Article: 0.6] [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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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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18
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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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19
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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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20
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Fogelqvist J, Verkhozina AV, Katyshev AI, Pucholt P, Dixelius C, Rönnberg-Wästljung AC, Lascoux M, Berlin S. Genetic and morphological evidence for introgression between three species of willows. BMC Evol Biol 2015; 15:193. [PMID: 26376815 PMCID: PMC4574262 DOI: 10.1186/s12862-015-0461-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 08/20/2015] [Indexed: 01/16/2023] Open
Abstract
Background Hybridization and introgression are said to occur relatively frequently in plants, and in particular among different species of willows. However, data on the actual frequency of natural hybridization and introgression is rare. Here, we report the first fine-scale genetic analysis of a contact zone shared between the three basket willow species, Salix dasyclados, S. schwerinii and S. viminalis in the vicinity of the Lake Baikal in Southern Siberia. Individuals were sampled in fourteen populations and classified as pure species or hybrids based on a set of morphological characters. They were then genotyped at 384 nuclear SNP and four chloroplast SSR loci. The STRUCTURE and NewHybrids softwares were used to estimate the frequency and direction of hybridization using genotypic data at the nuclear SNP loci. Results As many as 19 % of the genotyped individuals were classified as introgressed individuals and these were mainly encountered in the centre of the contact zone. All introgressed individuals were backcrosses to S. viminalis or S. schwerinii and no F1 or F2 hybrids were found. The rest of the genotyped individuals were classified as pure species and formed two clusters, one with S. schwerinii individuals and the other with S. viminalis and S. dasyclados individuals. The two clusters were significantly genetically differentiated, with FST = 0.333 (0.282–0.382, p < 0.001). In contrast, for the chloroplast haplotypes, no genetic differentiation was observed as they were completely shared between the species. Based on morphological classification only 5 % of the individuals were classified as introgressed individuals, which was much less than what was detected using genotypic data. Conclusions We have discovered a new willow hybrid zone with relatively high frequency of introgressed individuals. The low frequency of F1 hybrids indicates that ongoing hybridization is limited, which could be because of the presence of reproductive barriers or simply because the conditions are not favorable for hybridization. We further conclude that in order to get a complete picture of the species composition of a hybrid zone it is necessary to use a combination of morphological characters and genetic data from both nuclear and chloroplast markers. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0461-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Johan Fogelqvist
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, P.O. Box 7080, SE-75007, Uppsala, Sweden.
| | - Alla V Verkhozina
- Siberian Institute of Plant Physiology & Biochemistry, Irkutsk-33, P.O. Box 317, 664033, Irkutsk, Russia.
| | - Alexander I Katyshev
- Siberian Institute of Plant Physiology & Biochemistry, Irkutsk-33, P.O. Box 317, 664033, Irkutsk, Russia.
| | - Pascal Pucholt
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, P.O. Box 7080, SE-75007, Uppsala, Sweden.
| | - Christina Dixelius
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, P.O. Box 7080, SE-75007, Uppsala, Sweden.
| | - Ann Christin Rönnberg-Wästljung
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, P.O. Box 7080, SE-75007, Uppsala, Sweden.
| | - Martin Lascoux
- Uppsala University, Department of Ecology and Genetics, Evolutionary Biology Centre, Science for Life Laboratory, Norbyvägen 18D, 752 36, Uppsala, Sweden.
| | - Sofia Berlin
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, P.O. Box 7080, SE-75007, Uppsala, Sweden.
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Balao F, Casimiro-Soriguer R, García-Castaño JL, Terrab A, Talavera S. Big thistle eats the little thistle: does unidirectional introgressive hybridization endanger the conservation of Onopordum hinojense? THE NEW PHYTOLOGIST 2015; 206:448-458. [PMID: 25401776 DOI: 10.1111/nph.13156] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/28/2014] [Indexed: 06/04/2023]
Abstract
Hybridization is known to have a creative role in plant evolution. However, it can also have negative effects on parental species. Onopordum is a large genus whose species frequently hybridize. In the Southwest Iberian Peninsula, the rare O. hinojense co-occurs with the widely distributed O. nervosum, and hybrids between these two taxa have been described as O. × onubense. In this study we determine the extinction risk in a hybrid zone, both for hybrids and parentals, using analyses of morphological and cytogenetic traits as well as genetic markers and demographic models. To investigate the introgression process we used amplified fragment length polymorphism (AFLP) markers, Bayesian analyses and genome scan methods. Morphology, genome size and molecular markers confirmed homoploid hybridization and also indicated unidirectional backcrossing of F₁ hybrids with O. nervosum, which is likely to swamp O. hinojense, the parental with lower pollen size and a very low fruit set (8%). Genome scan methods revealed several loci significantly deviating from neutrality. Finally, our demographic modeling indicated that the higher fitness of O. nervosum threats the survival of O. hinojense by demographic swamping. Our study provides strong new evidence for a scenario of rapid extinction by unidirectional introgression and demographic swamping. The multifaceted approach used here sheds new light on the role of introgression in plant extinctions.
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Affiliation(s)
- Francisco Balao
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Apdo. 1095, 41080, Sevilla, Spain
- Department of Systematic and Evolutionary Botany, University of Vienna, Rennweg 14, 1030, Austria
| | - Ramón Casimiro-Soriguer
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Apdo. 1095, 41080, Sevilla, Spain
- Departmento de Biología, CASEM, Universidad de Cádiz, Campus Río San Pedro, E-11510, Puerto Real, Spain
| | - Juan Luis García-Castaño
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Apdo. 1095, 41080, Sevilla, Spain
| | - Anass Terrab
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Apdo. 1095, 41080, Sevilla, Spain
- Department of Systematic and Evolutionary Botany, University of Vienna, Rennweg 14, 1030, Austria
| | - Salvador Talavera
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Apdo. 1095, 41080, Sevilla, Spain
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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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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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High genetic diversity and low differentiation of Michelia coriacea (Magnoliaceae), a critically endangered endemic in Southeast Yunnan, China. Int J Mol Sci 2012; 13:4396-4411. [PMID: 22605985 PMCID: PMC3344221 DOI: 10.3390/ijms13044396] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 03/14/2012] [Accepted: 03/15/2012] [Indexed: 11/26/2022] Open
Abstract
Michelia coriacea, a critically endangered tree, has a restricted and fragmented distribution in Southeast Yunnan Province, China. The genetic diversity, genetic structure and gene flow in the three extant populations of this species were detected by 10 inter-simple sequence repeat (ISSR) markers and 11 simple sequence repeat (SSR) markers. Examination of genetic diversity revealed that the species maintained a relatively high level of genetic diversity at the species level (percentage of polymorphic bands) PPB = 96.36% from ISSRs; PPL (percentage of polymorphic loci) = 95.56% from SSRs, despite several fragmental populations. Low levels of genetic differentiation among the populations of M. coriacea were detected by Nei’s Gst = 0.187 for ISSR and Wright’s Fst = 0.090 for SSR markers, which is further confirmed by Bayesian model-based STRUCTURE and PCoA analysis that could not reveal a clear separation between populations, although YKP was differentiated to other two populations by ISSR markers. Meanwhile, AMOVA analysis also indicated that 22.84% and 13.90% of genetic variation existed among populations for ISSRs and SSRs, respectively. The high level of genetic diversity, low genetic differentiation, and the population, structure imply that the fragmented habitat and the isolated population of M. coriacea may be due to recent over-exploitation. Conservation and management of M. coriacea should concentrate on maintaining the high level of genetic variability through both in and ex-situ conservation actions.
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