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Köhler M, Oakley LJ, Font F, Peñas MLL, Majure LC. On the continuum of evolution: a putative new hybrid speciation event in Opuntia (Cactaceae) between a native and an introduced species in southern South America. SYST BIODIVERS 2021. [DOI: 10.1080/14772000.2021.1967510] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Matias Köhler
- Programa de Pós-Graduação em Botânica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- University of Florida Herbarium (FLAS), Florida Museum of Natural History, Gainesville, FL, USA
| | - Luis J. Oakley
- Cátedra de Botánica, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Santa Fe, Argentina
- Red List Authority Coordinator for the Temperate South American Plant Specialist Groups – International Union for Conservation of Nature (IUCN), Gland, Switzerland
| | - Fabián Font
- Herbario Museo de Farmacobotánica “Juan A. Domínguez” (BAF), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - M. Laura Las Peñas
- Instituto Multidisciplinario de Biología Vegetal (IMBIV), Facultas de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba – CONICET, Córdoba, Argentina
| | - Lucas C. Majure
- University of Florida Herbarium (FLAS), Florida Museum of Natural History, Gainesville, FL, USA
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102
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Cordero I, Jiménez MD, Delgado JA, Balaguer L, Pueyo JJ, Rincón A. Local adaptation optimizes photoprotection strategies in a Neotropical legume tree under drought stress. TREE PHYSIOLOGY 2021; 41:1641-1657. [PMID: 33611539 DOI: 10.1093/treephys/tpab034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 11/13/2020] [Accepted: 02/16/2021] [Indexed: 06/12/2023]
Abstract
Photoprotection is a plant functional mechanism to prevent photooxidative damage by excess light. This is most important when carbon assimilation is limited by drought, and as such, it entails a trade-off between carbon assimilation vs stress avoidance. The ecological adaptation of plants to local water availability can lead to different photoprotective strategies. To test this, we used different provenances of Caesalpinia spinosa (Mol.) Kuntze (commonly known as 'tara') along a precipitation gradient. Tara is a Neotropical legume tree with high ecological and commercial value, found in dry tropical forests, which are increasingly threatened by climate change. Morphological and physiological responses of tara provenances were analysed under three different treatments of drought and leaflet immobilization, i.e., light stress, in a common garden greenhouse experiment. Tara quickly responded to drought by reducing stomatal conductance, evapotranspiration, photochemical efficiency, carbon assimilation and growth, while increasing structural and chemical photoprotection (leaflet angle and pigments for thermal dissipation). Leaflet closure was an efficient photoprotection strategy with overall physiological benefits for seedlings as it diminished the evaporative demand and avoided photodamage, but also entailed costs by reducing net carbon assimilation opportunities. These responses depended on seed origin, with seedlings from the most xeric locations showing the highest dehydration tolerance, suggesting local adaptation and highlighting the value of different strategies under distinct environments. This plasticity in its response to environmental stress allows tara to thrive in locations with contrasting water availability. Our findings increase the understanding of the factors controlling the functional ecology of tara in response to drought, which can be leveraged to improve forecasts of changes in its distribution range, and for planning restoration projects with this keystone tree species.
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Affiliation(s)
- Irene Cordero
- Department of Soil, Plant, and Environmental Quality, Institute of Agricultural Sciences, Spanish National Research Council (ICA-CSIC), Serrano 115-bis, 28006 Madrid, Spain
- Department of Plant Biology I, Universidad Complutense de Madrid, José Antonio Nováis 10, 28040 Madrid, Spain
- Department of Earth and Environmental Sciences, The University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - María Dolores Jiménez
- Department of Biodiversity, Ecology and Evolution, Universidad Complutense de Madrid, José Antonio Nováis 10, 28040 Madrid, Spain
| | - Juan Antonio Delgado
- Department of Biodiversity, Ecology and Evolution, Universidad Complutense de Madrid, José Antonio Nováis 10, 28040 Madrid, Spain
| | - Luis Balaguer
- Department of Plant Biology I, Universidad Complutense de Madrid, José Antonio Nováis 10, 28040 Madrid, Spain
| | - José J Pueyo
- Department of Soil, Plant, and Environmental Quality, Institute of Agricultural Sciences, Spanish National Research Council (ICA-CSIC), Serrano 115-bis, 28006 Madrid, Spain
| | - Ana Rincón
- Department of Soil, Plant, and Environmental Quality, Institute of Agricultural Sciences, Spanish National Research Council (ICA-CSIC), Serrano 115-bis, 28006 Madrid, Spain
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103
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Zhang JX, Wang M, Fan J, Guo ZP, Guan Y, Qu G, Zhang CJ, Guo YX, Yan X. Non-linear genetic diversity and notable population differentiation caused by low gene flow of bermudagrass [ Cynodon dactylon (L.) Pers.] along longitude gradients. PeerJ 2021; 9:e11953. [PMID: 34458022 PMCID: PMC8378333 DOI: 10.7717/peerj.11953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 07/21/2021] [Indexed: 11/20/2022] Open
Abstract
Background Environmental variation related to ecological habitat is the main driver of plant adaptive divergence. Longitude plays an important role in the formation of plant population structure, indicating that environmental differentiation can significantly shape population structure. Methods Genetic diversity and population genetic structure were estimated using 105 expressed sequence tag-derived simple sequence repeat (EST-SSR) loci. A total of 249 C. dactylon (L.) Pers. (common bermudagrass) individuals were sampled from 13 geographic sites along the longitude (105°57′34″–119°27′06″E). Results There was no obvious linear trend of intra-population genetic diversity along longitude and the intra-population genetic diversity was not related to climate in this study. Low gene flow (Nm = 0.7701) meant a rich genetic differentiation among populations of C. dactylon along longitude gradients. Significantly positive Mantel correlation (r = 0.438, P = 0.001) was found between genetic distance and geographical interval while no significant partial Mantel correlation after controlling the effect of mean annual precipitation, which indicated geographic distance correlated with mean annual precipitation affect genetic distance. The genetic diversity of C. dactylon with higher ploidy level was higher than that with lower ploidy level and groups of individuals with higher ploidy level were separated further away by genetic distance from the lower ploidy levels. Understanding the different genetic bases of local adaptation comparatively between latitude and longitude is one of the core findings in the adaptive evolution of plants.
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Affiliation(s)
- Jing-Xue Zhang
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China.,College of Animal and Veterinary Science, Henan Agricultural University, Zhengzhou, Henan, China
| | - Miaoli Wang
- College of Animal and Veterinary Science, Henan Agricultural University, Zhengzhou, Henan, China
| | - Jibiao Fan
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
| | - Zhi-Peng Guo
- College of Animal and Veterinary Science, Henan Agricultural University, Zhengzhou, Henan, China
| | - Yongzhuo Guan
- College of Animal and Veterinary Science, Henan Agricultural University, Zhengzhou, Henan, China
| | - Gen Qu
- College of Animal and Veterinary Science, Henan Agricultural University, Zhengzhou, Henan, China
| | - Chuan-Jie Zhang
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
| | - Yu-Xia Guo
- College of Animal and Veterinary Science, Henan Agricultural University, Zhengzhou, Henan, China
| | - Xuebing Yan
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
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104
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Kawaguchi K, Ohya Y, Maekawa M, Iizuka T, Hasegawa A, Shiragaki K, He H, Oda M, Morikawa T, Yokoi S, Tezuka T. Two Nicotiana occidentalis accessions enable gene identification for Type II hybrid lethality by the cross to N. sylvestris. Sci Rep 2021; 11:17093. [PMID: 34429461 PMCID: PMC8384851 DOI: 10.1038/s41598-021-96482-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 08/11/2021] [Indexed: 12/18/2022] Open
Abstract
Hybrid lethality, meaning the death of F1 hybrid seedlings, has been observed in many plant species, including Nicotiana. Previously, we have revealed that hybrids of the selected Nicotiana occidentalis accession and N. tabacum, an allotetraploid with S and T genomes, exhibited lethality characterized by the fading of shoot color. The lethality was suggested to be controlled by alleles of loci on the S and T genomes derived from N. sylvestris and N. tomentosiformis, respectively. Here, we extended the analysis of hybrid lethality using other two accessions of N. occidentalis identified from the five tested accessions. The two accessions were crossed with N. tabacum and its two progenitors, N. sylvestris and N. tomentosiformis. After crosses with N. tabacum, the two N. occidentalis accessions yielded inviable hybrid seedlings whose lethality was characterized by the fading of shoot color, but only the T genome of N. tabacum was responsible for hybrid lethality. Genetic analysis indicated that first-mentioned N. occidentalis accession carries a single gene causing hybrid lethality by allelic interaction with the S genome.
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Affiliation(s)
- Kenji Kawaguchi
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
- NARO Hokkaido Agricultural Research Center, Memuro Research Station, 9-4 Shinsei-minami, Memuro, Kasai, Hokkaido, 082-0081, Japan
| | - Yuichiro Ohya
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
| | - Maho Maekawa
- School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
| | - Takahiro Iizuka
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
| | - Akira Hasegawa
- School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
| | - Kumpei Shiragaki
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
| | - Hai He
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
| | - Masayuki Oda
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
- Education and Research Field, College of Life, Environment, and Advanced Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
| | - Toshinobu Morikawa
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
- Education and Research Field, College of Life, Environment, and Advanced Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
| | - Shuji Yokoi
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
- Education and Research Field, College of Life, Environment, and Advanced Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
- Bioeconomy Research Institute, Research Center for the 21St Century, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
| | - Takahiro Tezuka
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan.
- Education and Research Field, College of Life, Environment, and Advanced Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan.
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105
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Zhang M, Wei H, Liu J, Bian Y, Ma Q, Mao G, Wang H, Wu A, Zhang J, Chen P, Ma L, Fu X, Yu S. Non-functional GoFLA19s are responsible for the male sterility caused by hybrid breakdown in cotton (Gossypium spp.). THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:1198-1212. [PMID: 34160096 DOI: 10.1111/tpj.15378] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/10/2021] [Accepted: 06/19/2021] [Indexed: 06/13/2023]
Abstract
Hybrid breakdown (HB) functions as a common reproductive barrier and reduces hybrid fitness in many species, including cotton. However, the related genes and the underlying genetic mechanisms of HB in cotton remain unknown. Here, we found that the photosensitive genetic male sterile line CCRI9106 was a hybrid progeny of Gossypium hirsutum and Gossypium barbadense and probably a product of HB. Fine mapping with F2 s (CCRI9106 × G. hirsutum/G. barbadense lines) identified a pair of male sterility genes GoFLA19s (encoding fasciclin-like arabinogalactan family protein) located on chromosomes A12 and D12. Crucial variations occurring in the fasciclin-like domain and the arabinogalactan protein domain were predicted to cause the non-functionalization of GbFLA19-D and GhFLA19-A. CRISPR/Cas9-mediated knockout assay confirmed the effects of GhFLA19s on male sterility. Sequence alignment analyses showed that variations in GbFLA19-D and GhFLA19-A likely occurred after the formation of allotetraploid cotton species. GoFLA19s are specifically expressed in anthers and contribute to tapetal development, exine assembly, intine formation, and pollen grain maturation. RNA-sequencing and quantitative reverse transcriptase-polymerase chain reaction analyses illustrated that genes related to these biological processes were significantly downregulated in the mutant. Our research on male sterility genes, GoFLA19s, improves the understanding of the molecular characteristics and evolutionary significance of HB in interspecific hybrid breeding.
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Affiliation(s)
- Meng Zhang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, 455000, China
| | - Hengling Wei
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, 455000, China
| | - Ji Liu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, 455000, China
| | - Yingjie Bian
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, 455000, China
| | - Qiang Ma
- College of Biology and Food Engineering, Anyang Institute of Technology, Anyang, Henan, 455000, China
| | - Guangzhi Mao
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, 455000, China
| | - Hantao Wang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, 455000, China
| | - Aimin Wu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, 455000, China
| | - Jingjing Zhang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, 455000, China
| | - Pengyun Chen
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, 455000, China
| | - Liang Ma
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, 455000, China
| | - Xiaokang Fu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, 455000, China
| | - Shuxun Yu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, 455000, China
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106
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Gorman CE, Li Y, Dorken ME, Stift M. No evidence for incipient speciation by selfing in North American Arabidopsis lyrata. J Evol Biol 2021; 34:1397-1405. [PMID: 34228843 DOI: 10.1111/jeb.13901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 05/01/2021] [Accepted: 07/03/2021] [Indexed: 01/01/2023]
Abstract
Self-fertilization inherently restricts gene flow by reducing the fraction of offspring that can be produced by inter-population matings. Therefore, mating system transitions from outcrossing to selfing could result in reproductive isolation between selfing and outcrossing lineages and provide a starting point for speciation. In newly diverged lineages, for example after a transition to selfing, further reproductive isolation can be caused by a variety of prezygotic and post-zygotic mechanisms that operate before, during and after pollination. In animals, prezygotic barriers tend to evolve faster than post-zygotic ones. This is not necessarily the case for plants, for which the relative importance of post-mating, post-fertilization and early-acting post-zygotic barriers has been investigated far less. To test whether post-pollination isolation exists between populations of North American Arabidopsis lyrata that differ in breeding (self-incompatible versus self-compatible) and mating system (outcrossing versus selfing), we compared patterns of seed set after crosses made within populations, between populations of the same mating system and between populations with different mating systems. We found no evidence for post-pollination isolation between plants from selfing populations (self-compatible, low outcrossing rates) and outcrossing populations (self-incompatible, high outcrossing rates) via either prezygotic or early-acting post-zygotic mechanisms. Together with the results of other studies indicating the absence of reproductive barriers acting before and during pollination, we conclude that the transition to selfing in this study system has not led to the formation of reproductive barriers between selfing and outcrossing populations of North American A. lyrata.
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Affiliation(s)
| | - Yan Li
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Marcel E Dorken
- Department of Biology, Trent University, Peterborough, ON, Canada
| | - Marc Stift
- Department of Biology, University of Konstanz, Konstanz, Germany
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107
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Milet-Pinheiro P, Santos PSC, Prieto-Benítez S, Ayasse M, Dötterl S. Differential Evolutionary History in Visual and Olfactory Floral Cues of the Bee-Pollinated Genus Campanula (Campanulaceae). PLANTS (BASEL, SWITZERLAND) 2021; 10:1356. [PMID: 34371561 PMCID: PMC8309401 DOI: 10.3390/plants10071356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/28/2021] [Accepted: 06/30/2021] [Indexed: 11/25/2022]
Abstract
Visual and olfactory floral signals play key roles in plant-pollinator interactions. In recent decades, studies investigating the evolution of either of these signals have increased considerably. However, there are large gaps in our understanding of whether or not these two cue modalities evolve in a concerted manner. Here, we characterized the visual (i.e., color) and olfactory (scent) floral cues in bee-pollinated Campanula species by spectrophotometric and chemical methods, respectively, with the aim of tracing their evolutionary paths. We found a species-specific pattern in color reflectance and scent chemistry. Multivariate phylogenetic statistics revealed no influence of phylogeny on floral color and scent bouquet. However, univariate phylogenetic statistics revealed a phylogenetic signal in some of the constituents of the scent bouquet. Our results suggest unequal evolutionary pathways of visual and olfactory floral cues in the genus Campanula. While the lack of phylogenetic signal on both color and scent bouquet points to external agents (e.g., pollinators, herbivores) as evolutionary drivers, the presence of phylogenetic signal in at least some floral scent constituents point to an influence of phylogeny on trait evolution. We discuss why external agents and phylogeny differently shape the evolutionary paths in floral color and scent of closely related angiosperms.
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Affiliation(s)
- Paulo Milet-Pinheiro
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Albert-Einstein Allee, 89081 Ulm, Germany; (P.S.C.S.); (M.A.)
| | - Pablo Sandro Carvalho Santos
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Albert-Einstein Allee, 89081 Ulm, Germany; (P.S.C.S.); (M.A.)
| | - Samuel Prieto-Benítez
- Departamento de Biología y Geología, Física y Química Inorgánica, Universidad Rey Juan Carlos-ESCET, C/Tulipán, s/n, Móstoles, 28933 Madrid, Spain;
- Ecotoxicology of Air Pollution Group, Environmental Department, CIEMAT, Avda. Complutense, 40, 28040 Madrid, Spain
| | - Manfred Ayasse
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Albert-Einstein Allee, 89081 Ulm, Germany; (P.S.C.S.); (M.A.)
| | - Stefan Dötterl
- Department of Biosciences, Paris-Lodron-University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria;
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108
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Bowers JE, Paterson AH. Chromosome number is key to longevity of polyploid lineages. THE NEW PHYTOLOGIST 2021; 231:19-28. [PMID: 33772797 DOI: 10.1111/nph.17361] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Polyploidy is ubiquitous and often recursive in plant lineages, most frequently resulting in extinction but occasionally associated with great evolutionary success. However, instead of chromosome numbers exponentially increasing due to recurrent polyploidy, most angiosperm species have fewer than 14 chromosome pairs. Following genome duplication, diploidisation can render one copy of essential genes nonfunctional without fitness cost. In isolated subpopulations, alternate (homoeologous) gene copies can be lost, creating incompatibilities that reduce fitness of hybrids between subpopulations, constraining exchange of favourable genetic changes and reducing species fitness. When multiple sets of incompatible genes are genetically linked, their deleterious effects are not independent. The effective number of independently acting sets of incompatible loci in hybrids is limited by chromosome number and recombination. Therefore, species with many chromosomes are subject to a higher fitness penalty during diploidisation. Karyotypic changes, especially fusions, that reduce gene flow are normally fitness disadvantages, but during the diploidisation process, can increase fitness by reducing mixing of differentially diploidised alleles. Fitness penalties caused by diploidisation favour accelerated karyotypic change, with each change increasing barriers to gene flow, contributing to speciation. Lower chromosome numbers and increased chromosome fusions confer advantages to surviving the diploidisation process following polyploid formation, by independent mechanisms.
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Affiliation(s)
- John E Bowers
- Plant Genome Mapping Laboratory, University of Georgia, Athens, GA, 30602, USA
| | - Andrew H Paterson
- Plant Genome Mapping Laboratory, University of Georgia, Athens, GA, 30602, USA
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109
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Sassone AB, Hojsgaard DH, Giussani LM, Brassac J, Blattner FR. Genomic, karyological and morphological changes of South American garlics (Ipheion) provide insights into mechanisms of speciation in the Pampean region. Mol Ecol 2021; 30:3716-3729. [PMID: 34087027 DOI: 10.1111/mec.16009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/19/2021] [Accepted: 05/21/2021] [Indexed: 01/15/2023]
Abstract
Speciation proceeds through mechanisms that promote reproductive isolation and shape the extent of genetic variation in natural populations, and thus its study is essential to understand the evolutionary processes leading to increased biodiversity. Chromosomal rearrangements are known to facilitate reproductive isolation by hybrid sterility and favour speciation events. The genus Ipheion (Amaryllidaceae, Allioideae) is unique as its species exhibit a remarkable karyological variability but lack population-level genetic data. To unveil the diversification processes acting upon the formation of new lineages within Ipheion in the Pampas of South America, we combined morphology and karyology approaches with genotyping-by-sequencing. Our phylogenomic and population genomics results supported the taxonomic division of Ipheion into three morphological and genetically well-differentiated groups. The origin of Ipheion uniflorum was traced back to its current southern distribution area in the southern Pampean region (in Argentina), from where it had expanded to the north reaching Uruguay. Our results further suggested that chromosome rearrangements and ploidy shifts had triggered speciation events, first during the origin of I. uniflorum and later during its subsequent diversification into I. recurvifolium and I. tweedieanum, in both cases reinforced by extrinsic factors and biogeographical settings. The current study illustrates the analytical power of multidisciplinary approaches integrating phylo- and population genomics with classic analyses to reveal evolutionary processes in plants.
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Affiliation(s)
- Agostina B Sassone
- Instituto de Botánica Darwinion, CONICET-ANCEFN, Buenos Aires, Argentina.,Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Diego H Hojsgaard
- Department of Systematics, Biodiversity, and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Goettingen, Germany
| | - Liliana M Giussani
- Instituto de Botánica Darwinion, CONICET-ANCEFN, Buenos Aires, Argentina
| | - Jonathan Brassac
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Frank R Blattner
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
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110
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Abstract
Pollen-pistil interactions serve as important prezygotic reproductive barriers that play a critical role in mate selection in plants. Here, we highlight recent progress toward understanding the molecular basis of pollen-pistil interactions as reproductive isolating barriers. These barriers can be active systems of pollen rejection, or they can result from a mismatch of required male and female factors. In some cases, the barriers are mechanistically linked to self-incompatibility systems, while others represent completely independent processes. Pollen-pistil reproductive barriers can act as soon as pollen is deposited on a stigma, where penetration of heterospecific pollen tubes is blocked by the stigma papillae. As pollen tubes extend, the female transmitting tissue can selectively limit growth by producing cell wall-modifying enzymes and cytotoxins that interact with the growing pollen tube. At ovules, differential pollen tube attraction and inhibition of sperm cell release can act as barriers to heterospecific pollen tubes.
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Affiliation(s)
- Amanda K Broz
- Department of Biology, Colorado State University, Fort Collins, Colorado 80523-1878, USA; ,
| | - Patricia A Bedinger
- Department of Biology, Colorado State University, Fort Collins, Colorado 80523-1878, USA; ,
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111
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Zhang Y, Chen J, Sun H. Alpine speciation and morphological innovations: revelations from a species-rich genus in the northern hemisphere. AOB PLANTS 2021; 13:plab018. [PMID: 34025962 PMCID: PMC8129467 DOI: 10.1093/aobpla/plab018] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 04/14/2021] [Indexed: 06/06/2023]
Abstract
A large number of studies have attempted to determine the mechanisms driving plant diversity and distribution on a global scale, but the diverse and endemic alpine herbs found in harsh environments, showing adaptive evolution, require more studies. Here, we selected 466 species from the genus Saussurea, one of the northern hemisphere's highest-altitude plant genera with high species richness and striking morphological traits, to explore the mechanisms driving speciation and adaptative evolution. We conducted phylogenetic signals analysis and ancestral character estimation to explore the phylogenetic significance of ecological factors. Moreover, we used spatial simultaneous autoregressive (SAR) error models, modified t-tests and partial regression models to quantify the relative effects of ecological factors and morphological diversity upon diversity and endemism of Saussurea. Phylogenetic analyses reveal that geological influences and climate stability exhibit significant phylogenetic signals and that Saussurea originated at a relatively high elevation. Regression models indicate that geological influences and climatic stability significantly affect the diversity and endemism patterns of Saussurea and its morphological innovations. Moreover, morphological innovations in an area show significant contributions to the local diversity and endemism of Saussurea. We conclude that geological influences (mean altitude and topographic heterogeneity), glacial-interglacial climate stability and phylogenetic conservatism have together promoted the speciation and adaptive evolution of the genus Saussurea. In addition, adaptively morphological innovations of alpine species also promote diversification in local regions. Our findings improve the understanding of the distribution pattern of diversity/endemism and adaptive evolution of alpine specie in the whole northern hemisphere.
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Affiliation(s)
- Yazhou Zhang
- CAS Key Laboratory for Plant Biodiversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, No. 132, Lanhei Road, Kunming 650201, Yunnan, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianguo Chen
- CAS Key Laboratory for Plant Biodiversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, No. 132, Lanhei Road, Kunming 650201, Yunnan, China
| | - Hang Sun
- CAS Key Laboratory for Plant Biodiversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, No. 132, Lanhei Road, Kunming 650201, Yunnan, China
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112
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Introgression is widespread in the radiation of carnivorous Nepenthes pitcher plants. Mol Phylogenet Evol 2021; 163:107214. [PMID: 34052438 DOI: 10.1016/j.ympev.2021.107214] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 05/14/2021] [Accepted: 05/25/2021] [Indexed: 11/23/2022]
Abstract
Introgression and hybridization are important processes in plant evolution, but they are difficult to study from a phylogenetic perspective, because they conflict with the bifurcating evolutionary history typically depicted in phylogenetic models. The role of hybridization in plant evolution is best documented in the form of allo-polyploidizations. In contrast, homoploid hybridization and introgression are less explored, although they may be crucial in adaptive radiations. Here we employ genome-wide data (ddRAD-seq, transcriptomes) to investigate the evolutionary history of Nepenthes, a radiation of c. 160 species of iconic carnivorous plants mainly from tropical Asia. Our data indicates that the main radiation is only c. 5 million years old, and confirms previous bifurcating phylogenies. However, due to a greatly expanded number of loci, we were able test for the first time the long-standing hypotheses of introgression and historical hybridization. The genus presents one very clear case of organellar capture between two distantly related but sympatric groups. Furthermore, all Nepenthes species show introgression signals in their nuclear genomes, as uncovered by a general survey of ABBA-BABA-like statistics. The ancestor of the rapid main radiation shows ancestry from two deeply diverged lineages, as indicated by phylogenetic network analyses. All major clades of the main radiation show further introgression both within and between each other, as suggested by admixture graphs. Our study supports the hypothesis that rapid adaptive radiations are hotspots of introgression in the tree of life, and highlights the need to consider non-treelike processes in evolutionary studies of Nepenthes in particular.
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113
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Li W, Wang S, Hu J, Tang C, Wu C, Liu J, Ren L, Sun C, Dong J, Liu S, Ye X. Asymmetric expression of homoeologous genes contributes to dietary adaption of an allodiploid hybrid fish derived from Megalobrama amblycephala (♀) × Culter alburnus (♂). BMC Genomics 2021; 22:362. [PMID: 34011285 PMCID: PMC8132401 DOI: 10.1186/s12864-021-07639-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 04/21/2021] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Hybridization, which can quickly merge two or more divergent genomes and form new allopolyploids, is an important technique in fish genetic breeding. However, the merged subgenomes must adjust and coexist with one another in a single nucleus, which may cause subgenome interaction and dominance at the gene expression level and has been observed in some allopolyploid plants. In our previous studies, newly formed allodiploid hybrid fish derived from herbivorous Megalobrama amblycephala (♀) × carnivorous Culter alburnus (♂) had herbivorous characteristic. It is thus interesting to further characterize whether the subgenome interaction and dominance derive dietary adaptation of this hybrid fish. RESULTS Differential expression, homoeolog expression silencing and bias were investigated in the hybrid fish after 70 days of adaptation to carnivorous and herbivorous diets. A total of 2.65 × 108 clean reads (74.06 Gb) from the liver and intestinal transcriptomes were mapped to the two parent genomes based on specific SNPs. A total of 2538 and 4385 differentially expressed homoeologous genes (DEHs) were identified in the liver and intestinal tissues between the two groups of fish, respectively, and these DEHs were highly enriched in fat digestion and carbon metabolism, amino acid metabolism and steroid biosynthesis. Furthermore, subgenome dominance were observed in tissues, with paternal subgenome was more dominant than maternal subgenome. Moreover, subgenome expression dominance controlled functional pathways in metabolism, disease, cellular processes, environment and genetic information processing during the two dietary adaptation processes. In addition, few but sturdy villi in the intestine, significant fat accumulation and a higher concentration of malondialdehyde in the liver were observed in fish fed carnivorous diet compared with fish fed herbivorous diet. CONCLUSIONS Our results indicated that diet drives phenotypic and genetic variation, and the asymmetric expression of homoeologous genes (including differential expression, expression silencing and bias) may play key roles in dietary adaptation of hybrid fish. Subgenome expression dominance may contribute to uncovering the mechanistic basis of heterosis and also provide perspectives for fish genetic breeding and application.
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Affiliation(s)
- Wuhui Li
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081 Hunan China
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510380 Guangdong China
| | - Shi Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081 Hunan China
| | - Jie Hu
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510380 Guangdong China
| | - Chenchen Tang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081 Hunan China
| | - Chang Wu
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081 Hunan China
| | - Junmei Liu
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081 Hunan China
| | - Li Ren
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081 Hunan China
| | - Chengfei Sun
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510380 Guangdong China
| | - Junjian Dong
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510380 Guangdong China
| | - Shaojun Liu
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081 Hunan China
| | - Xing Ye
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510380 Guangdong China
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114
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Discovery of a dune‐building hybrid beachgrass (
Ammophila arenaria
×
A. breviligulata
) in the U.S. Pacific Northwest. Ecosphere 2021. [DOI: 10.1002/ecs2.3501] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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115
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Köhler C, Dziasek K, Del Toro-De León G. Postzygotic reproductive isolation established in the endosperm: mechanisms, drivers and relevance. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200118. [PMID: 33866810 DOI: 10.1098/rstb.2020.0118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The endosperm is a developmental innovation of angiosperms that supports embryo growth and germination. Aside from this essential reproductive function, the endosperm fuels angiosperm evolution by rapidly establishing reproductive barriers between incipient species. Specifically, the endosperm prevents hybridization of newly formed polyploids with their non-polyploid progenitors, a phenomenon termed the triploid block. Furthermore, recently diverged diploid species are frequently reproductively isolated by endosperm-based hybridization barriers. Current genetic approaches have revealed a prominent role for epigenetic processes establishing these barriers. In particular, imprinted genes, which are expressed in a parent-of-origin-specific manner, underpin the interploidy barrier in the model species Arabidopsis. We will discuss the mechanisms establishing hybridization barriers in the endosperm, the driving forces for these barriers and their impact for angiosperm evolution. This article is part of the theme issue 'How does epigenetics influence the course of evolution?'
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Affiliation(s)
- Claudia Köhler
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala 75007, Sweden
| | - Katarzyna Dziasek
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala 75007, Sweden
| | - Gerardo Del Toro-De León
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala 75007, Sweden
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116
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Wang J, Dong S, Yang L, Harris A, Schneider H, Kang M. Allopolyploid Speciation Accompanied by Gene Flow in a Tree Fern. Mol Biol Evol 2021; 37:2487-2502. [PMID: 32302390 DOI: 10.1093/molbev/msaa097] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Hybridization in plants may result in hybrid speciation or introgression and, thus, is now widely understood to be an important mechanism of species diversity on an evolutionary timescale. Hybridization is particularly common in ferns, as is polyploidy, which often results from hybrid crosses. Nevertheless, hybrid speciation as an evolutionary process in fern lineages remains poorly understood. Here, we employ flow cytometry, phylogeny, genomewide single nucleotide polymorphism data sets, and admixture and coalescent modeling to show that the scaly tree fern, Gymnosphaera metteniana is a naturally occurring allotetraploid species derived from hybridization between the diploids, G. denticulata and G. gigantea. Moreover, we detected ongoing gene flow between the hybrid species and its progenitors, and we found that G. gigantea and G. metteniana inhabit distinct niches, whereas climatic niches of G. denticulata and G. metteniana largely overlap. Taken together, these results suggest that either some degree of intrinsic genetic isolation between the hybrid species and its parental progenitors or ecological isolation over short distances may be playing an important role in the evolution of reproductive barriers. Historical climate change may have facilitated the origin of G. metteniana, with the timing of hybridization coinciding with a period of intensification of the East Asian monsoon during the Pliocene and Pleistocene periods in southern China. Our study of allotetraploid G. metteniana represents the first genomic-level documentation of hybrid speciation in scaly tree ferns and, thus, provides a new perspective on evolution in the lineage.
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Affiliation(s)
- Jing Wang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.,Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Shiyong Dong
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.,Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Lihua Yang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.,Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Aj Harris
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.,Department of Biology, Oberlin College, Oberlin, OH
| | - Harald Schneider
- Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
| | - Ming Kang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.,Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
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117
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The Evolutionary History, Diversity, and Ecology of Willows (Salix L.) in the European Alps. DIVERSITY-BASEL 2021. [DOI: 10.3390/d13040146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The genus Salix (willows), with 33 species, represents the most diverse genus of woody plants in the European Alps. Many species dominate subalpine and alpine types of vegetation. Despite a long history of research on willows, the evolutionary and ecological factors for this species richness are poorly known. Here we will review recent progress in research on phylogenetic relationships, evolution, ecology, and speciation in alpine willows. Phylogenomic reconstructions suggest multiple colonization of the Alps, probably from the late Miocene onward, and reject hypotheses of a single radiation. Relatives occur in the Arctic and in temperate Eurasia. Most species are widespread in the European mountain systems or in the European lowlands. Within the Alps, species differ ecologically according to different elevational zones and habitat preferences. Homoploid hybridization is a frequent process in willows and happens mostly after climatic fluctuations and secondary contact. Breakdown of the ecological crossing barriers of species is followed by introgressive hybridization. Polyploidy is an important speciation mechanism, as 40% of species are polyploid, including the four endemic species of the Alps. Phylogenomic data suggest an allopolyploid origin for all taxa analyzed so far. Further studies are needed to specifically analyze biogeographical history, character evolution, and genome evolution of polyploids.
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118
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Hernández-Hernández T, Miller EC, Román-Palacios C, Wiens JJ. Speciation across the Tree of Life. Biol Rev Camb Philos Soc 2021; 96:1205-1242. [PMID: 33768723 DOI: 10.1111/brv.12698] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 02/13/2021] [Accepted: 02/16/2021] [Indexed: 01/04/2023]
Abstract
Much of what we know about speciation comes from detailed studies of well-known model systems. Although there have been several important syntheses on speciation, few (if any) have explicitly compared speciation among major groups across the Tree of Life. Here, we synthesize and compare what is known about key aspects of speciation across taxa, including bacteria, protists, fungi, plants, and major animal groups. We focus on three main questions. Is allopatric speciation predominant across groups? How common is ecological divergence of sister species (a requirement for ecological speciation), and on what niche axes do species diverge in each group? What are the reproductive isolating barriers in each group? Our review suggests the following patterns. (i) Based on our survey and projected species numbers, the most frequent speciation process across the Tree of Life may be co-speciation between endosymbiotic bacteria and their insect hosts. (ii) Allopatric speciation appears to be present in all major groups, and may be the most common mode in both animals and plants, based on non-overlapping ranges of sister species. (iii) Full sympatry of sister species is also widespread, and may be more common in fungi than allopatry. (iv) Full sympatry of sister species is more common in some marine animals than in terrestrial and freshwater ones. (v) Ecological divergence of sister species is widespread in all groups, including ~70% of surveyed species pairs of plants and insects. (vi) Major axes of ecological divergence involve species interactions (e.g. host-switching) and habitat divergence. (vii) Prezygotic isolation appears to be generally more widespread and important than postzygotic isolation. (viii) Rates of diversification (and presumably speciation) are strikingly different across groups, with the fastest rates in plants, and successively slower rates in animals, fungi, and protists, with the slowest rates in prokaryotes. Overall, our study represents an initial step towards understanding general patterns in speciation across all organisms.
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Affiliation(s)
- Tania Hernández-Hernández
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721-0088, U.S.A.,Catedrática CONACYT asignada a LANGEBIO-UGA Cinvestav, Libramiento Norte Carretera León Km 9.6, 36821, Irapuato, Guanajuato, Mexico
| | - Elizabeth C Miller
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721-0088, U.S.A
| | - Cristian Román-Palacios
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721-0088, U.S.A
| | - John J Wiens
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721-0088, U.S.A
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119
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Malaviya DR, Roy AK, Kaushal P, Pathak S, Kalendar R. Phenotype study of multifoliolate leaf formation in Trifolium alexandrinum L. PeerJ 2021; 9:e10874. [PMID: 33717683 PMCID: PMC7936568 DOI: 10.7717/peerj.10874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/11/2021] [Indexed: 12/02/2022] Open
Abstract
Background The genus Trifolium is characterized by typical trifoliolate leaves. Alterations in leaf formats from trifoliolate to multifoliolate, i.e., individual plants bearing trifoliolate, quadrifoliolate, pentafoliolate or more leaflets, were previously reported among many species of the genus. The study is an attempt to develop pure pentafoliolate plants of T. alexandrinum and to understand its genetic control. Methods The experimental material consisted of two populations of T. alexandrinum with multifoliolate leaf expression, i.e.,interspecific hybrid progenies of T. alexandrinum with T. apertum, and T. alexandrinum genotype Penta-1. Penetrance of the multifoliolate trait was observed among multifoliolate and trifoliolate plant progenies. In vitro culture and regeneration of plantlets from the axillary buds from different plant sources was also attempted. Results The inheritance among a large number of plant progenies together with in vitro micro-propagation results did not establish a definite pattern. The multifoliolate leaf formation was of chimeric nature, i.e., more than one leaf format appearing on individual branches. Reversal to normal trifoliolate from multifoliolate was also quite common. Penetrance and expression of multifoliolate leaf formation was higher among the plants raised from multifoliolate plants. Multifoliolate and pure pentafoliolate plants were observed in the progenies of pure trifoliolate plants and vice-versa. There was an apparent increase in the pentafoliolate leaf formation frequency over the years due to targeted selection. A few progenies of the complete pentafoliolate plants in the first year were true breeding in the second year. Frequency of plantlets with multifoliolate leaf formation was also higher in in vitro axillary bud multiplication when the explant bud was excised from the multifoliolate leaf node. Conclusion Number of leaflets being a discrete variable, occurrence of multifoliolate leaves on individual branches, reversal of leaf formats on branches and developing true breeding pentafoliolates were the factors leading to a hypothesis beyond normal Mendelian inheritance. Transposable elements (TEs) involved in leaf development in combination with epigenetics were probably responsible for alterations in the expression of leaflet number. Putative TE’s movement owing to chromosomal rearrangements possibly resulted in homozygous pentafoliolate trait with evolutionary significance. The hypothesis provides a new insight into understanding the genetic control of this trait in T. alexandrinum and may also be useful in other Trifolium species where such observations are reported.
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Affiliation(s)
- Devendra Ram Malaviya
- ICAR - Indian Institute of Sugarcane Research, Lucknow, India.,ICAR - Indian Grassland and Fodder Research Institute, Jhansi, India
| | - Ajoy Kumar Roy
- ICAR - Indian Grassland and Fodder Research Institute, Jhansi, India
| | - Pankaj Kaushal
- ICAR - Indian Grassland and Fodder Research Institute, Jhansi, India.,ICAR - National Institute of Biotic Stress Management, Raipur, India
| | - Shalini Pathak
- ICAR - Indian Grassland and Fodder Research Institute, Jhansi, India
| | - Ruslan Kalendar
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Uusimaa, Finland.,National Laboratory Astana, Nazarbayev University, Nur-Sultan, Aqmola, Kazakhstan
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120
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Lv Z, Li Z, Wang M, Zhao F, Zhang W, Li C, Gong L, Zhang Y, Mason AS, Liu B. Conservation and trans-regulation of histone modification in the A and B subgenomes of polyploid wheat during domestication and ploidy transition. BMC Biol 2021; 19:42. [PMID: 33750361 PMCID: PMC7944620 DOI: 10.1186/s12915-021-00985-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 02/17/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Polyploidy has played a prominent role in the evolution of plants and many other eukaryotic lineages. However, how polyploid genomes adapt to the abrupt presence of two or more sets of chromosomes via genome regulation remains poorly understood. Here, we analyzed genome-wide histone modification and gene expression profiles in relation to domestication and ploidy transition in the A and B subgenomes of polyploid wheat. RESULTS We found that epigenetic modification patterns by two typical euchromatin histone markers, H3K4me3 and H3K27me3, for the great majority of homoeologous triad genes in A and B subgenomes were highly conserved between wild and domesticated tetraploid wheats and remained stable in the process of ploidy transitions from hexaploid to extracted tetraploid and then back to resynthesized hexaploid. However, a subset of genes was differentially modified during tetraploid and hexaploid wheat domestication and in response to ploidy transitions, and these genes were enriched for particular gene ontology (GO) terms. The extracted tetraploid wheat manifested higher overall histone modification levels than its hexaploid donor, and which were reversible and restored to normal levels in the resynthesized hexaploid. Further, while H3K4me3 marks were distally distributed along each chromosome and significantly correlated with subgenome expression as expected, H3K27me3 marks showed only a weak distal bias and did not show a significant correlation with gene expression. CONCLUSIONS Our results reveal overall high stability of histone modification patterns in the A and B subgenomes of polyploid wheat during domestication and in the process of ploidy transitions. However, modification levels of a subset of functionally relevant genes in the A and B genomes were trans-regulated by the D genome in hexaploid wheat.
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Affiliation(s)
- Zhenling Lv
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
- Department of Plant Breeding, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany
- Department of Plant Breeding, University of Bonn, Katzenburgweg 5, 53115, Bonn, Germany
| | - Zijuan Li
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Meiyue Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Fei Zhao
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Wenjie Zhang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Changping Li
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Lei Gong
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Yijng Zhang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
| | - Annaliese S Mason
- Department of Plant Breeding, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
- Department of Plant Breeding, University of Bonn, Katzenburgweg 5, 53115, Bonn, Germany.
| | - Bao Liu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China.
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121
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Sandstedt GD, Wu CA, Sweigart AL. Evolution of multiple postzygotic barriers between species of the Mimulus tilingii complex. Evolution 2021; 75:600-613. [PMID: 33044006 PMCID: PMC7987689 DOI: 10.1111/evo.14105] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 09/04/2020] [Accepted: 09/21/2020] [Indexed: 12/17/2022]
Abstract
Species are often defined by their ability to interbreed (i.e., Biological Species Concept), but determining how and why reproductive isolation arises between new species can be challenging. In the Mimulus tilingii species complex, three species (M. caespitosa, M. minor, and M. tilingii) are largely allopatric and grow exclusively at high elevations (>2000 m). The extent to which geographic separation has shaped patterns of divergence among the species is not well understood. In this study, we determined that the three species are morphologically and genetically distinct, yet recently diverged. Additionally, we performed reciprocal crosses within and between the species and identified several strong postzygotic reproductive barriers, including hybrid seed inviability, F1 hybrid necrosis, and F1 hybrid male and female sterility. In this study, such postzygotic barriers are so strong that a cross between any species pair in the M. tilingii complex would cause nearly complete reproductive isolation. We consider how geographical and topographical patterns may have facilitated the evolution of several postzygotic barriers and contributed to speciation of closely related members within the M. tilingii species complex.
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Affiliation(s)
| | - Carrie A. Wu
- Department of Biology, University of Richmond, Richmond, Virginia 23173
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122
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Orsucci M, Sicard A. Flower evolution in the presence of heterospecific gene flow and its contribution to lineage divergence. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:971-989. [PMID: 33537708 DOI: 10.1093/jxb/eraa549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 11/16/2020] [Indexed: 06/12/2023]
Abstract
The success of species depends on their ability to exploit ecological resources in order to optimize their reproduction. However, species are not usually found within single-species ecosystems but in complex communities. Because of their genetic relatedness, closely related lineages tend to cluster within the same ecosystem, rely on the same resources, and be phenotypically similar. In sympatry, they will therefore compete for the same resources and, in the case of flowering plants, exchange their genes through heterospecific pollen transfer. These interactions, nevertheless, pose significant challenges to species co-existence because they can lead to resource limitation and reproductive interference. In such cases, divergent selective pressures on floral traits will favour genotypes that isolate or desynchronize the reproduction of sympatric lineages. The resulting displacement of reproductive characters will, in turn, lead to pre-mating isolation and promote intraspecific divergence, thus initiating or reinforcing the speciation process. In this review, we discuss the current theoretical and empirical knowledge on the influence of heterospecific pollen transfer on flower evolution, highlighting its potential to uncover the ecological and genomic constraints shaping the speciation process.
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Affiliation(s)
- Marion Orsucci
- Department of Plant Biology, Swedish University of Agricultural, Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Adrien Sicard
- Department of Plant Biology, Swedish University of Agricultural, Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
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123
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G J Hodel R, Zimmer E, Wen J. A phylogenomic approach resolves the backbone of Prunus (Rosaceae) and identifies signals of hybridization and allopolyploidy. Mol Phylogenet Evol 2021; 160:107118. [PMID: 33609711 DOI: 10.1016/j.ympev.2021.107118] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 02/01/2021] [Accepted: 02/08/2021] [Indexed: 10/22/2022]
Abstract
The genus Prunus, which contains 250-400 species, has ample genomic resources for the economically important taxa in the group including cherries, peaches, and almonds. However, the backbone of Prunus, specifically the position of the racemose group relative to the solitary and corymbose groups, remains phylogenetically uncertain. Surprisingly, phylogenomic analyses to resolve relationships in the genus are lacking. Here, we assemble transcriptomes from 17 Prunus species representing four subgenera, and use existing transcriptome assemblies, to resolve key relationships in the genus using a phylogenomic approach. From the transcriptomes, we constructed 21-taxon datasets of putatively single-copy nuclear genes with 591 and 379 genes, depending on taxon-occupancy filtering. Plastome sequences were obtained or assembled for all species present in the nuclear data set. The backbone of Prunus was resolved consistently in the nuclear and chloroplast phylogenies, but we found substantial cytonuclear discord within subgenera. Our nuclear phylogeny recovered a monophyletic racemose group, contrasting with previous studies finding paraphyly that suggests repeated allopolyploidy early in the evolutionary history of the genus. However, we detected multiple species with histories consistent with hybridization and allopolyploidy, including a deep hybridization event involving subgenus Amygdalus and the Armeniaca clade in subgenus Prunus. Analyses of gene tree conflict revealed substantial discord at several nodes, including the crown node of the racemose group. Alternative gene tree topologies that conflicted with the species tree were consistent with a paraphyletic racemose group, highlighting the complex reticulated evolutionary history of this group.
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Affiliation(s)
- Richard G J Hodel
- Department of Botany, National Museum of Natural History, MRC 166, Smithsonian Institution, Washington, DC 20013-7012, USA.
| | - Elizabeth Zimmer
- Department of Botany, National Museum of Natural History, MRC 166, Smithsonian Institution, Washington, DC 20013-7012, USA
| | - Jun Wen
- Department of Botany, National Museum of Natural History, MRC 166, Smithsonian Institution, Washington, DC 20013-7012, USA
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Ecological and spatial patterns associated with diversification of South American Physaria (Brassicaceae) through the general concept of species. ORG DIVERS EVOL 2021. [DOI: 10.1007/s13127-021-00486-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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125
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Arida BL, Scopece G, Machado RM, Moraes AP, Forni-Martins E, Pinheiro F. Reproductive barriers and fertility of two neotropical orchid species and their natural hybrid. Evol Ecol 2021. [DOI: 10.1007/s10682-020-10095-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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126
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Tao D, McNally KL, Koide Y, Matsubara K. Editorial: Reproductive Barriers and Gene Introgression in Rice Species. FRONTIERS IN PLANT SCIENCE 2021; 12:699761. [PMID: 34456942 PMCID: PMC8385636 DOI: 10.3389/fpls.2021.699761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 07/15/2021] [Indexed: 05/03/2023]
Affiliation(s)
- Dayun Tao
- Yunnan Key Laboratory for Rice Genetic Improvement, Food Crops Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China
- *Correspondence: Dayun Tao
| | - Kenneth L. McNally
- T. T. Chang Genetic Resources Center, International Rice Research Institute, Los Baños, Philippines
- Kenneth L. McNally
| | - Yohei Koide
- Laboratory of Plant Breeding, Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
- Yohei Koide
| | - Kazuki Matsubara
- Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Japan
- Kazuki Matsubara
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127
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Grünig S, Fischer M, Parisod C. Recent hybrid speciation at the origin of the narrow endemic Pulmonaria helvetica. ANNALS OF BOTANY 2021; 127:21-31. [PMID: 32738145 PMCID: PMC7750729 DOI: 10.1093/aob/mcaa145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 05/23/2023]
Abstract
BACKGROUND AND AIMS Hybridization is known to drive plant speciation through the establishment of homoploid or allopolyploid hybrid species. Here we investigate the origin of Pulmonaria helvetica, a narrow endemic species described across a restricted area of Switzerland that was entirely covered by ice during the last glacial maximum. This species presents an original number of chromosomes (2n = 24) and morphological traits suggestive of a hybrid origin. METHODS We sequenced a plastid locus and 1077 double-digest restriction-site-associated DNA (ddRAD) loci in 67 individuals from across the distribution range of P. helvetica and candidate progenitor species growing in the same area. Assignment of genotypes to main genetic clusters within and among taxa using STRUCTURE tested whether P. helvetica represents a genetically differentiated lineage and addressed the hypothesis of its hybrid origin. Comparative ecological modelling further addressed possible niche differentiation among taxa. KEY RESULTS Pulmonaria helvetica was highlighted as a genetically homogeneous species distinct from co-occurring taxa. Consistent with a scenario of hybrid speciation, it presented clear evidence of balanced admixture between Pulmonaria officinalis (2n = 16) and Pulmonaria mollis s.l. (2n = 18, 22), which was also highlighted as a maternal progenitor based on plastid sequences. Limited genetic structure within the maternal progenitor is consistent with an origin of P. helvetica through either homoploid hybridization with considerable karyotype changes or via complex scenarios of allopolyploidy involving a dysploid taxon of P. mollis s.l. Comparative niche modelling indicated non-significant ecological differences between P. helvetica and its progenitors, supporting intrinsic factors resulting from hybridization as main drivers of speciation. CONCLUSIONS Hybridization appears as a major process having promoted the postglacial origin of the narrow endemic P. helvetica, suggesting hybrid speciation as an effective process that rapidly produces new species under climate changes.
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Affiliation(s)
- Sandra Grünig
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, Bern, Switzerland
| | - Markus Fischer
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, Bern, Switzerland
| | - Christian Parisod
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, Bern, Switzerland
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128
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Li C, Ohadi S, Mesgaran MB. Asymmetry in fitness-related traits of later-generation hybrids between two invasive species. AMERICAN JOURNAL OF BOTANY 2021; 108:51-62. [PMID: 33316089 DOI: 10.1002/ajb2.1583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 09/14/2020] [Indexed: 06/12/2023]
Abstract
PREMISE The importance of hybridization to invasion has been frequently discussed, with most studies focusing on the comparison of fitness-related traits between F1 hybrids and their parents and the consequences of such fitness differences. However, relatively little attention has been given to late-generation hybrids. Different fitness landscapes could emerge in later generations after hybrids cross with each other or backcross with their parents, which may play an important role in plant invasion and subsequent speciation. METHODS In this study, artificial crosses were conducted to generate multiple generations, including F1, F2, and backcrosses between two invasive species: Cakile edentula (self-compatible) and C. maritima (self-incompatible). Putative hybrids were also collected in the sympatric zone and compared with their co-occurring parents for phenotypic and genetic differences. RESULTS Genetic data provided evidence of hybridization happening in the wild, and phenotypic comparisons showed that natural hybrids had intermediate traits between the two species but showed more similarity to C. maritima than to C. edentula. The asymmetry was further identified in artificial generations for several phenotypic characters. Furthermore, backcrosses exhibited different patterns of variation, with backcrosses to C. maritima having higher reproductive output than their counterparts. CONCLUSIONS Our results suggest that hybridization and introgression (backcrossing) in Cakile species is asymmetric and most likely to favor the proliferation of C. maritima genes in the mixed population and thus help its establishment, a finding that could not be predicted by characterizing F1 hybrids.
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Affiliation(s)
- Chengjun Li
- Institute of Environmental Research at Greater Bay Area, Guangzhou University, Guangzhou, 510006, China
- School of BioSciences, the University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Sara Ohadi
- School of BioSciences, the University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Mohsen B Mesgaran
- School of BioSciences, the University of Melbourne, Melbourne, Victoria, 3010, Australia
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Duchoslav M, Jandová M, Kobrlová L, Šafářová L, Brus J, Vojtěchová K. Intricate Distribution Patterns of Six Cytotypes of Allium oleraceum at a Continental Scale: Niche Expansion and Innovation Followed by Niche Contraction With Increasing Ploidy Level. FRONTIERS IN PLANT SCIENCE 2020; 11:591137. [PMID: 33362819 PMCID: PMC7755979 DOI: 10.3389/fpls.2020.591137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 11/06/2020] [Indexed: 05/23/2023]
Abstract
The establishment and success of polyploids are thought to often be facilitated by ecological niche differentiation from diploids. Unfortunately, most studies compared diploids and polyploids, ignoring variation in ploidy level in polyploids. To fill this gap, we performed a large-scale study of 11,163 samples from 1,283 populations of the polyploid perennial geophyte Allium oleraceum with reported mixed-ploidy populations, revealed distribution ranges of cytotypes, assessed their niches and explored the pattern of niche change with increasing ploidy level. Altogether, six ploidy levels (3x-8x) were identified. The most common were pentaploids (53.6%) followed by hexaploids (22.7%) and tetraploids (21.6%). Higher cytotype diversity was found at lower latitudes than at higher latitudes (>52° N), where only tetraploids and pentaploids occurred. We detected 17.4% of mixed-ploidy populations, usually as a combination of two, rarely of three, cytotypes. The majority of mixed-ploidy populations were found in zones of sympatry of the participating cytotypes, suggesting they have arisen through migration (secondary contact zone). Using coarse-grained variables (climate, soil), we found evidence of both niche expansion and innovation in tetraploids related to triploids, whereas higher ploidy levels showed almost zero niche expansion, but a trend of increased niche unfilling of tetraploids. Niche unfilling in higher ploidy levels was caused by a contraction of niche envelopes toward lower continentality of the climate and resulted in a gradual decrease of niche breadth and a gradual shift in niche optima. Field-recorded data indicated wide habitat breadth of tetraploids and pentaploids, but also a pattern of increasing synanthropy in higher ploidy levels. Wide niche breadth of tetra- and pentaploids might be related to their multiple origins from different environmental conditions, higher "age", and retained sexuality, which likely preserve their adaptive potential. In contrast, other cytotypes with narrower niches are mostly asexual, probably originating from a limited range of contrasting environments. Persistence of local ploidy mixtures could be enabled by the perenniality of A. oleraceum and its prevalence of vegetative reproduction, facilitating the establishment and decreasing exclusion of minority cytotype due to its reproductive costs. Vegetative reproduction might also significantly accelerate colonization of new areas, including recolonization of previously glaciated areas.
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Affiliation(s)
- Martin Duchoslav
- Plant Biosystematics and Ecology RG, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Michaela Jandová
- Plant Biosystematics and Ecology RG, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czechia
- Institute of Botany, Czech Academy of Sciences, Pruhonice, Czechia
| | - Lucie Kobrlová
- Plant Biosystematics and Ecology RG, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Lenka Šafářová
- Plant Biosystematics and Ecology RG, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Jan Brus
- Department of Geoinformatics, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Kateřina Vojtěchová
- Plant Biosystematics and Ecology RG, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czechia
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Musker SD, Ellis AG, Schlebusch SA, Verboom GA. Niche specificity influences gene flow across fine-scale habitat mosaics in Succulent Karoo plants. Mol Ecol 2020; 30:175-192. [PMID: 33152114 DOI: 10.1111/mec.15721] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/23/2020] [Accepted: 10/26/2020] [Indexed: 11/26/2022]
Abstract
While the tempo of diversification in biodiversity hotspots has received much attention, the spatial scale of diversification has often been overlooked. Addressing this deficiency requires understanding the drivers of population divergence and the spatial scales at which they operate in species-rich clades and ecosystems. South Africa's Succulent Karoo (SK) hotspot provides an excellent system for such research, being both compact (ca. 110,000 km2 ) and home to spectacular in-situ radiations, such as the ruschioid Aizoaceae. Here we use GBS to document genetic structure in two co-occurring ruschioid species, at both coarse (>10 km) and fine (<500 m) spatial scales. Where Ruschia burtoniae shows strong between-population genetic differentiation and no gene flow, Conophytum calculus shows weak differentiation, with high levels of admixture suggesting recent or ongoing gene flow. Community analysis and transplant experiments reveal that R. burtoniae occupies a narrow, low-pH edaphic niche, and at scales of a few hundred metres, areas of elevated genetic turnover correspond to patches of edaphically unsuitable habitat. In contrast, C. calculus occupies a broader niche and exhibits isolation-by-distance without a habitat effect. We suggest that edaphic specialisation, coupled with highly restricted seed and pollen dispersal in heterogeneous landscapes, has played a major role in driving rapid diversification at small spatial scales in this system. However, the contrasting patterns in our study species show that these factors do not influence all organisms uniformly, being strongly modulated by lineage-specific traits that influence both the spatial scale of gene flow and habitat specificity.
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Affiliation(s)
- Seth D Musker
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa.,Department of Biology, University of Bayreuth, Bayreuth, Germany
| | - Allan G Ellis
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
| | - Stephen A Schlebusch
- Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, South Africa
| | - G Anthony Verboom
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
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Gorman CE, Bond L, van Kleunen M, Dorken ME, Stift M. Limited phenological and pollinator-mediated isolation among selfing and outcrossing Arabidopsis lyrata populations. Proc Biol Sci 2020; 287:20202323. [PMID: 33234079 DOI: 10.1098/rspb.2020.2323] [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] [Indexed: 11/12/2022] Open
Abstract
Transitions from outcrossing to selfing have been a frequent evolutionary shift in plants and clearly play a role in species divergence. However, many questions remain about the initial mechanistic basis of reproductive isolation during the evolution of selfing. For instance, how important are pre-zygotic pre-pollination mechanisms (e.g. changes in phenology and pollinator visitation) in maintaining reproductive isolation between newly arisen selfing populations and their outcrossing ancestors? To test whether changes in phenology and pollinator visitation isolate selfing populations of Arabidopsis lyrata from outcrossing populations, we conducted a common garden experiment with plants from selfing and outcrossing populations as well as their between-population hybrids. Specifically, we asked whether there was isolation between outcrossing and selfing plants and their between-population hybrids through differences in (1) the timing or intensity of flowering; and/or (2) pollinator visitation. We found that phenology largely overlapped between plants from outcrossing and selfing populations. There were also no differences in pollinator preference related to mating system. Additionally, pollinators preferred to visit flowers on the same plant rather than exploring nearby plants, creating a large opportunity for self-fertilization. Overall, this suggests that pre-zygotic pre-pollination mechanisms do not strongly reproductively isolate plants from selfing and outcrossing populations of Arabidopsis lyrata.
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Affiliation(s)
- Courtney E Gorman
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
| | - Lindsay Bond
- Department of Biology, Trent University, 1600 West Bank Drive, Peterborough, Ontario, Canada K9J 0G2
| | - Mark van Kleunen
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany.,Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou 318000, People's Republic of China
| | - Marcel E Dorken
- Department of Biology, Trent University, 1600 West Bank Drive, Peterborough, Ontario, Canada K9J 0G2
| | - Marc Stift
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
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Barke BH, Karbstein K, Daubert M, Hörandl E. The relation of meiotic behaviour to hybridity, polyploidy and apomixis in the Ranunculus auricomus complex (Ranunculaceae). BMC PLANT BIOLOGY 2020; 20:523. [PMID: 33203395 PMCID: PMC7672892 DOI: 10.1186/s12870-020-02654-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 09/20/2020] [Indexed: 05/23/2023]
Abstract
BACKGROUND Hybridization and polyploidization are powerful evolutionary factors that are associated with manifold developmental changes in plants such as irregular progression of meiosis and sporogenesis. The emergence of apomixis, which is asexual reproduction via seeds, is supposed to be connected to these factors and was often regarded as an escape from hybrid sterility. However, the functional trigger of apomixis is still unclear. Recently formed di- and polyploid Ranunculus hybrids, as well as their parental species were analysed for their modes of mega- and microsporogenesis by microscopy. Chromosomal configurations during male meiosis were screened for abnormalities. Meiotic and developmental abnormalities were documented qualitatively and collected quantitatively for statistical evaluations. RESULTS Allopolyploids showed significantly higher frequencies of erroneous microsporogenesis than homoploid hybrid plants. Among diploids, F2 hybrids had significantly more disturbed meiosis than F1 hybrids and parental plants. Chromosomal aberrations included laggard chromosomes, chromatin bridges and disoriented spindle activities. Failure of megasporogenesis appeared to be much more frequent in than of microsporogenesis is correlated to apomixis onset. CONCLUSIONS Results suggest diverging selective pressures on female and male sporogenesis, with only minor effects of hybridity on microsporogenesis, but fatal effects on the course of megasporogenesis. Hence, pollen development continues without major alterations, while selection will favour apomixis as alternative to the female meiotic pathway. Relation of investigated errors of megasporogenesis with the observed occurrence of apospory in Ranunculus hybrids identifies disturbed female meiosis as potential elicitor of apomixis in order to rescue these plants from hybrid sterility. Male meiotic disturbance appears to be stronger in neopolyploids than in homoploid hybrids, while disturbances of megasporogenesis were not ploidy-dependent.
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Affiliation(s)
- Birthe H Barke
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, D-37073, Goettingen, Germany.
| | - Kevin Karbstein
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, D-37073, Goettingen, Germany
| | - Mareike Daubert
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, D-37073, Goettingen, Germany
- Present Address: Carl von Ossietzky University, Institute of Biology and Environmental Sciences, Carl von Ossietzky Straße 9-11, D-26129, Oldenburg, Germany
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, D-37073, Goettingen, Germany
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133
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Coetzee A, Spottiswoode CN, Seymour CL. Post-pollination barriers enable coexistence of pollinator-sharing ornithophilous Erica species. JOURNAL OF PLANT RESEARCH 2020; 133:873-881. [PMID: 32997284 DOI: 10.1007/s10265-020-01226-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 09/23/2020] [Indexed: 06/11/2023]
Abstract
Some evolutionary radiations produce a number of closely-related species that continue to coexist. In such plant systems, when pre-pollination barriers are weak, relatively strong post-pollination reproductive barriers are required to maintain species boundaries. Even when post-pollination barriers are in place, however, reproductive interference and pollinator dependence may strengthen selection for pre-pollination barriers. We assessed whether coexistence of species from the unusually speciose Erica genus in the fynbos biome, South Africa, is enabled through pre-pollination or post-pollination barriers. We also tested for reproductive interference and pollinator dependence. We investigated this in natural populations of three bird-pollinated Erica species (Erica plukenetii, E. curviflora and E. coccinea), which form part of a large guild of congeneric species that co-flower and share a single pollinator species (Orange-breasted Sunbird Anthobaphes violacea). At least two of the three pre-pollination barriers assessed (distribution ranges, flowering phenology and flower morphology) were weak in each species pair. Hand-pollination experiments revealed that seed set from heterospecific pollination (average 8%) was significantly lower than seed set from outcross pollination (average 50%), supporting the hypothesis that species boundaries are maintained through post-pollination barriers. Reproductive interference, assessed in one population by applying outcross pollen three hours after applying heterospecific pollen, significantly reduced seed set compared to outcross pollen alone. This may drive selection for traits that enhance pre-pollination barriers, particularly given that two of the three species were self-sterile, and therefore pollinator dependent. This study suggests that post-pollination reproductive barriers could facilitate the coexistence of congeneric species, in a recent radiation with weak pre-pollination reproductive barriers.
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Affiliation(s)
- Anina Coetzee
- FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa.
| | - Claire N Spottiswoode
- FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
| | - Colleen L Seymour
- FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
- South African National Biodiversity Institute, Kirstenbosch Research Centre, Claremont, 7753, South Africa
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134
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Castro M, Loureiro J, Husband BC, Castro S. The role of multiple reproductive barriers: strong post-pollination interactions govern cytotype isolation in a tetraploid-octoploid contact zone. ANNALS OF BOTANY 2020; 126:991-1003. [PMID: 32353869 PMCID: PMC7596367 DOI: 10.1093/aob/mcaa084] [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: 12/18/2019] [Accepted: 04/23/2020] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Polyploidy is an important contributor to sympatric speciation and assortative mating is a key mechanism driving cytotype interactions in contact zones. While strong reproductive barriers can mediate the coexistence of different cytotypes in sympatry, positive frequency-dependent mating disadvantage ultimately drives the transition to single-ploidy populations. However, comprehensive estimates of reproductive isolation among cytotypes and across multiple barriers are rare. We quantify the strength of isolation across multiple reproductive stages in a tetraploid-octoploid contact zone to understand the potential for coexistence. METHODS Assortative mating due to flowering asynchrony, pollinator behaviour, morphological overlap, self-fertilization and gametic competition between tetraploid and octoploid Gladiolus communis in a contact zone in the Western Iberian Peninsula were assessed in natural and experimental populations to quantify reproductive isolation (RI) between cytotypes. KEY RESULTS Tetraploids and octoploids have a high degree of overlap in flowering time and similar floral morphology, and are visited by generalist insects without cytotype foraging preferences, resulting in weak pre-pollination RI (from 0.00 to 0.21). In contrast, post-pollination isolation resulting from gametic selection was a strong barrier to inter-cytotype mating, with ploidy composition in stigmatic pollen loads determining the levels of RI (from 0.54 to 1.00). Between-cytotype cross-incompatibility was relatively high (RI from 0.54 to 0.63) as was isolation acquired through self-pollination (RI of 0.59 in tetraploids and 0.39 in octoploids). CONCLUSIONS Total RI was high for both tetraploids (from 0.90 to 1.00) and octoploids (from 0.78 to 0.98). Such high rates of assortative mating will enable cytotype coexistence in mixed-ploidy populations by weakening the impacts of minority cytotype exclusion. This study reveals the key role of gametic selection in cytotype siring success and highlights the importance of comprehensive estimates across multiple reproductive barriers to understand cytotype interactions at contact zones.
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Affiliation(s)
- Mariana Castro
- University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Calçada Martim de Freitas, Coimbra, Portugal
| | - João Loureiro
- University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Calçada Martim de Freitas, Coimbra, Portugal
| | - Brian C Husband
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Sílvia Castro
- University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Calçada Martim de Freitas, Coimbra, Portugal
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135
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Sutherland BL, Miranda-Katz T, Galloway LF. Strength in numbers? Cytotype frequency mediates effect of reproductive barriers in mixed-ploidy arrays. Evolution 2020; 74:2281-2292. [PMID: 32776511 DOI: 10.1111/evo.14077] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 05/14/2020] [Accepted: 05/18/2020] [Indexed: 01/14/2023]
Abstract
When differentiated lineages come into contact, their fates depend on demographic and reproductive factors. These factors have been well-studied in taxa of the same ploidy, but less is known about sympatric lineages that differ in ploidy, particularly with respect to demographic factors. We assessed prezygotic, postzygotic, and total reproductive isolation in naturally pollinated arrays of diploid-tetraploid and tetraploid-hexaploid population mixes of Campanula rotundifolia by measuring pollinator transitions, seed yield, germination rate, and proportion of hybrid offspring. Four frequencies of each cytotype were tested, and pollinators consistently overvisited rare cytotypes. Seed yield and F1 hybrid production were greater in 4X-6X arrays than 2X-4X arrays, whereas germination rates were similar, creating two distinct patterns of reproductive isolation. In 2X-4X arrays, postzygotic isolation was near complete (3% hybrid offspring), and prezygotic isolation associated with pollinator preference is expected to facilitate the persistence of minority cytotypes. However, in 4X-6X arrays where postzygotic isolation permitted hybrid formation (44% hybrids), pollinator behavior drove patterns of reproductive isolation, with rare cytotypes being more isolated and greater gene flow expected from rare into common cytotypes. In polyploid complexes, both the specific cytotypes in contact and local cytotype frequency, likely reflecting spatial demography, will influence likelihood of gene exchange.
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Affiliation(s)
- Brittany L Sutherland
- Mountain Lake Biological Station and Department of Biology, University of Virginia, Charlottesville, Virginia, 22904
| | - Tomas Miranda-Katz
- Mountain Lake Biological Station and Department of Biology, University of Virginia, Charlottesville, Virginia, 22904
| | - Laura F Galloway
- Mountain Lake Biological Station and Department of Biology, University of Virginia, Charlottesville, Virginia, 22904
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Buck R, Hyasat S, Hossfeld A, Flores-Rentería L. Patterns of hybridization and cryptic introgression among one- and four-needled pinyon pines. ANNALS OF BOTANY 2020; 126:401-411. [PMID: 32222765 PMCID: PMC7424738 DOI: 10.1093/aob/mcaa045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/27/2020] [Indexed: 05/28/2023]
Abstract
BACKGROUND AND AIMS Pinyon pine hybridization is widely acknowledged, but the frequency of and contributors to such interspecific mating remain largely unstudied. Pinus quadrifolia has three to four needles per fascicle, suggesting that it is a result of hybridization between the five-needled P. juarezensis and the single-needled P. monophylla. In this study we address the taxonomic validity of P. juarezensis, the hybrid origin of P. quadrifolia and the presence of hybridization and intermediate morphology as a result of interspecific hybridization in this complex. METHODS We address these questions by combining a genomic and morphological approach. We generated 1868 single nucleotide polymorphisms (SNPs) to detect genetic clusters using principal co-ordinates analyis, discriminant analysis of principal components, fastSTRUCTURE and ADMIXTURE analyses, and performed a morphological analysis of the leaves. KEY RESULTS We found that the five-needled pinyons did not differ genetically from the four-needled P. quadrifolia, reducing the status of P. juarezensis to P. quadrifolia. We also found no evidence that P. quadrifolia is of hybrid origin from P. juarezensis × P. monophylla but is instead a genetically distinct species with natural needle number variation that has yet to be explained. Hybridization does occur in this complex, but mostly between P. quadrifolia and P. californiarum, and less commonly between P. quadrifolia and P. monophylla. Interestingly, some hybrid derivatives were detected between both single-needled taxa, P. monophylla and P. californiarum, a hybrid combination that has not yet been proposed. Hybrids have intermediate morphology when they have similar genetic contributions from both parental species; however, when one parent contributes more, hybrid derivatives resemble the parent with higher genetic contribution, resulting in cryptic introgression. CONCLUSIONS Our detailed sampling across the distribution of this complex allows us to describe the patterns of hybridization among these taxa, resolves an ancient taxonomic conflict and provides insights into the challenges of exclusively using morphological traits when identifying these taxa with cryptic hybridization and variable morphology.
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Affiliation(s)
- Ryan Buck
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Sandra Hyasat
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Alice Hossfeld
- Department of Biology, San Diego State University, San Diego, CA, USA
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137
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Phillips RD, Peakall R, van der Niet T, Johnson SD. Niche Perspectives on Plant-Pollinator Interactions. TRENDS IN PLANT SCIENCE 2020; 25:779-793. [PMID: 32386827 DOI: 10.1016/j.tplants.2020.03.009] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 03/12/2020] [Accepted: 03/25/2020] [Indexed: 05/03/2023]
Abstract
Ecological niches are crucial for species coexistence and diversification, but the niche concept has been underutilized in studying the roles of pollinators in plant evolution and reproduction. Pollination niches can be objectively characterized using pollinator traits, abundance, and distributions, as well as network topology. We review evidence that floral traits represent adaptations to pollination niches, where tradeoffs in trait deployment reinforce niche specialization. In turn, specialized pollination niches potentially increase speciation rates, foster species coexistence, and constrain species range limits. By linking studies of adaptation with those on speciation and coexistence, the pollination niche provides an organizing principle for research on plant reproduction, and conceptually unites these studies with fields of biology where the niche perspective is already firmly established.
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Affiliation(s)
- Ryan D Phillips
- Department of Ecology, Environment, and Evolution, La Trobe University, VIC 3086, Australia; Kings Park Science, Department of Biodiversity, Conservation, and Attractions, WA 6005, Australia; Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia.
| | - Rod Peakall
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
| | - Timotheüs van der Niet
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, P Bag X01, Scottsville 3209, South Africa
| | - Steven D Johnson
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, P Bag X01, Scottsville 3209, South Africa
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138
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Coughlan JM, Matute DR. The importance of intrinsic postzygotic barriers throughout the speciation process. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190533. [PMID: 32654642 DOI: 10.1098/rstb.2019.0533] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Intrinsic postzygotic barriers can play an important and multifaceted role in speciation, but their contribution is often thought to be reserved to the final stages of the speciation process. Here, we review how intrinsic postzygotic barriers can contribute to speciation, and how this role may change through time. We outline three major contributions of intrinsic postzygotic barriers to speciation. (i) reduction of gene flow: intrinsic postzygotic barriers can effectively reduce gene exchange between sympatric species pairs. We discuss the factors that influence how effective incompatibilities are in limiting gene flow. (ii) early onset of species boundaries via rapid evolution: intrinsic postzygotic barriers can evolve between recently diverged populations or incipient species, thereby influencing speciation relatively early in the process. We discuss why the early origination of incompatibilities is expected under some biological models, and detail how other (and often less obvious) incompatibilities may also serve as important barriers early on in speciation. (iii) reinforcement: intrinsic postzygotic barriers can promote the evolution of subsequent reproductive isolation through processes such as reinforcement, even between relatively recently diverged species pairs. We incorporate classic and recent empirical and theoretical work to explore these three facets of intrinsic postzygotic barriers, and provide our thoughts on recent challenges and areas in the field in which progress can be made. This article is part of the theme issue 'Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers'.
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Affiliation(s)
- Jenn M Coughlan
- Department of Biology, University of North Carolina, 120 South Road, Coker Hall, Chapel Hill, NC 27599, USA
| | - Daniel R Matute
- Department of Biology, University of North Carolina, 120 South Road, Coker Hall, Chapel Hill, NC 27599, USA
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139
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Ma ZY, Wen J, Tian JP, Gui LL, Liu XQ. Testing morphological trait evolution and assessing species delimitations in the grape genus using a phylogenomic framework. Mol Phylogenet Evol 2020; 148:106809. [DOI: 10.1016/j.ympev.2020.106809] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 03/05/2020] [Accepted: 03/23/2020] [Indexed: 12/15/2022]
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140
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Misiewicz TM, Simmons TS, Fine PVA. The contribution of multiple barriers to reproduction between edaphically divergent lineages in the Amazonian tree Protium subserratum (Burseraceae). Ecol Evol 2020; 10:6646-6663. [PMID: 32724539 PMCID: PMC7381562 DOI: 10.1002/ece3.6396] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/30/2020] [Accepted: 04/22/2020] [Indexed: 11/09/2022] Open
Abstract
Disentangling the strength and importance of barriers to reproduction that arise between diverging lineages is central to our understanding of species origin and maintenance. To date, the vast majority of studies investigating the importance of different barriers to reproduction in plants have focused on short-lived temperate taxa while studies of reproductive isolation in trees and tropical taxa are rare. Here, we systematically examine multiple barriers to reproduction in an Amazonian tree, Protium subserratum (Burseraceae) with diverging lineages of soil specialist ecotypes. Using observational, molecular, distributional, and experimental data, we aimed to quantify the contributions of individual prezygotic and postzygotic barriers including ecogeographic isolation, flowering phenology, pollinator assemblage, pollen adhesion, pollen germination, pollen tube growth, seed development, and hybrid fitness to total reproductive isolation between the ecotypes. We were able to identify five potential barriers to reproduction including ecogeographic isolation, phenological differences, differences in pollinator assemblages, differential pollen adhesion, and low levels of hybrid seed development. We demonstrate that ecogeographic isolation is a strong and that a combination of intrinsic and extrinsic prezygotic and postzygotic barriers may be acting to maintain near complete reproductive isolation between edaphically divergent populations of the tropical tree, P. subserratum.
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Affiliation(s)
- Tracy M. Misiewicz
- Department of Integrative Biology, University and Jepson HerbariaUniversity of CaliforniaBerkeleyCAUSA
| | - Tracey S. Simmons
- Department of Biological SciencesSan Jose State UniversitySan JoseCAUSA
| | - Paul V. A. Fine
- Department of Integrative Biology, University and Jepson HerbariaUniversity of CaliforniaBerkeleyCAUSA
- Department of Integrative BiologyEssig Museum of EntomologyUniversity and Jepson HerbariaUniversity of CaliforniaBerkeleyCAUSA
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141
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Bartholomé J, Mabiala A, Burlett R, Bert D, Leplé JC, Plomion C, Gion JM. The pulse of the tree is under genetic control: eucalyptus as a case study. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:338-356. [PMID: 32142191 DOI: 10.1111/tpj.14734] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 01/16/2020] [Accepted: 02/17/2020] [Indexed: 06/10/2023]
Abstract
The pulse of the tree (diurnal cycle of stem radius fluctuations) has been widely studied as a way of analyzing tree responses to the environment, including the phenotypic plasticity of tree-water relationships in particular. However, the genetic basis of this daily phenotype and its interplay with the environment remain largely unexplored. We characterized the genetic and environmental determinants of this response, by monitoring daily stem radius fluctuation (dSRF) on 210 trees from a Eucalyptus urophylla × E. grandis full-sib family over 2 years. The dSRF signal was broken down into hydraulic capacitance, assessed as the daily amplitude of shrinkage (DA), and net growth, estimated as the change in maximum radius between two consecutive days (ΔR). The environmental determinants of these two traits were clearly different: DA was positively correlated with atmospheric variables relating to water demand, while ΔR was associated with soil water content. The heritability for these two traits ranged from low to moderate over time, revealing a time-dependent or environment-dependent complex genetic determinism. We identified 686 and 384 daily quantitative trait loci (QTL) representing 32 and 31 QTL regions for DA and ΔR, respectively. The identification of gene networks underlying the 27 major genomics regions for both traits generated additional hypotheses concerning the biological mechanisms involved in response to water demand and supply. This study highlights that environmentally induced changes in daily stem radius fluctuation are genetically controlled in trees and suggests that these daily responses integrated over time shape the genetic architecture of mature traits.
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Affiliation(s)
- Jérôme Bartholomé
- BIOGECO, INRAE, University of Bordeaux, 33610, Cestas, France
- CIRAD, UMR AGAP, F-34398, Montpellier, France
- AGAP, University of Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
| | | | - Régis Burlett
- BIOGECO, INRAE, University of Bordeaux, 33610, Cestas, France
| | - Didier Bert
- BIOGECO, INRAE, University of Bordeaux, 33610, Cestas, France
| | | | | | - Jean-Marc Gion
- BIOGECO, INRAE, University of Bordeaux, 33610, Cestas, France
- CIRAD, UMR AGAP, F-34398, Montpellier, France
- AGAP, University of Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
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142
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Butlin RK, Stankowski S. Is it time to abandon the biological species concept? No. Natl Sci Rev 2020; 7:1400-1401. [PMID: 34692168 PMCID: PMC8288981 DOI: 10.1093/nsr/nwaa109] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Roger K Butlin
- Department of Animal and Plant Sciences, University of Sheffield, UK
- Department of Marine Sciences, University of Gothenburg, Sweden
| | - Sean Stankowski
- Department of Animal and Plant Sciences, University of Sheffield, UK
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143
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Irwin DE. Assortative Mating in Hybrid Zones Is Remarkably Ineffective in Promoting Speciation. Am Nat 2020; 195:E150-E167. [DOI: 10.1086/708529] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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144
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Lin YH, Zhang S, Zhu M, Lu T, Chen K, Wen Z, Wang S, Xiao G, Luo D, Jia Y, Li L, MacConmara M, Hoshida Y, Singal A, Yopp A, Wang T, Zhu H. Mice With Increased Numbers of Polyploid Hepatocytes Maintain Regenerative Capacity But Develop Fewer Hepatocellular Carcinomas Following Chronic Liver Injury. Gastroenterology 2020; 158:1698-1712.e14. [PMID: 31972235 PMCID: PMC8902703 DOI: 10.1053/j.gastro.2020.01.026] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 12/24/2019] [Accepted: 01/02/2020] [Indexed: 01/07/2023]
Abstract
BACKGROUND & AIMS Thirty to 90% of hepatocytes contain whole-genome duplications, but little is known about the fates or functions of these polyploid cells or how they affect development of liver disease. We investigated the effects of continuous proliferative pressure, observed in chronically damaged liver tissues, on polyploid cells. METHODS We studied Rosa-rtTa mice (controls) and Rosa-rtTa;TRE-short hairpin RNA mice, which have reversible knockdown of anillin, actin binding protein (ANLN). Transient administration of doxycycline increases the frequency and degree of hepatocyte polyploidy without permanently altering levels of ANLN. Mice were then given diethylnitrosamine and carbon tetrachloride (CCl4) to induce mutations, chronic liver damage, and carcinogenesis. We performed partial hepatectomies to test liver regeneration and then RNA-sequencing to identify changes in gene expression. Lineage tracing was used to rule out repopulation from non-hepatocyte sources. We imaged dividing hepatocytes to estimate the frequency of mitotic errors during regeneration. We also performed whole-exome sequencing of 54 liver nodules from patients with cirrhosis to quantify aneuploidy, a possible outcome of polyploid cell divisions. RESULTS Liver tissues from control mice given CCl4 had significant increases in ploidy compared with livers from uninjured mice. Mice with knockdown of ANLN had hepatocyte ploidy above physiologic levels and developed significantly fewer liver tumors after administration of diethylnitrosamine and CCl4 compared with control mice. Increased hepatocyte polyploidy was not associated with altered regenerative capacity or tissue fitness, changes in gene expression, or more mitotic errors. Based on lineage-tracing experiments, non-hepatocytes did not contribute to liver regeneration in mice with increased polyploidy. Despite an equivalent rate of mitosis in hepatocytes of differing ploidies, we found no lagging chromosomes or micronuclei in mitotic polyploid cells. In nodules of human cirrhotic liver tissue, there was no evidence of chromosome-level copy number variations. CONCLUSIONS Mice with increased polyploid hepatocytes develop fewer liver tumors following chronic liver damage. Remarkably, polyploid hepatocytes maintain the ability to regenerate liver tissues during chronic damage without generating mitotic errors, and aneuploidy is not commonly observed in cirrhotic livers. Strategies to increase numbers of polypoid hepatocytes might be effective in preventing liver cancer.
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Affiliation(s)
- Yu-Hsuan Lin
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine
| | - Shuyuan Zhang
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine
| | - Min Zhu
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine
| | - Tianshi Lu
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine,Quantitative Biomedical Research Center, Department of Population and Data Sciences
| | - Kenian Chen
- Quantitative Biomedical Research Center, Department of Population and Data Sciences
| | - Zhuoyu Wen
- Quantitative Biomedical Research Center, Department of Population and Data Sciences
| | - Shidan Wang
- Quantitative Biomedical Research Center, Department of Population and Data Sciences
| | - Guanghua Xiao
- Quantitative Biomedical Research Center, Department of Population and Data Sciences
| | - Danni Luo
- Quantitative Biomedical Research Center, Department of Population and Data Sciences
| | - Yuemeng Jia
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine
| | - Lin Li
- Children’s Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine
| | | | | | | | | | - Tao Wang
- Quantitative Biomedical Research Center, Department of Population and Data Sciences,Kidney Cancer Program, Simmons Comprehensive Cancer Center,Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Hao Zhu
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.
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145
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Porturas LD, Segraves KA. Whole genome duplication does not promote common modes of reproductive isolation in Trifolium pratense. AMERICAN JOURNAL OF BOTANY 2020; 107:833-841. [PMID: 32329070 DOI: 10.1002/ajb2.1466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 02/10/2020] [Indexed: 06/11/2023]
Abstract
PREMISE Although polyploidy has been studied since the early 1900s, fundamental aspects of polyploid ecology and evolution remain unexplored. In particular, surprisingly little is known about how newly formed polyploids (neopolyploids) become demographically established. Models predict that most polyploids should go extinct within the first few generations as a result of reproductive disadvantages associated with being the minority in a primarily diploid population (i.e., the minority cytotype principle), yet polyploidy is extremely common. Therefore, a key goal in the study of polyploidy is to determine the mechanisms that promote polyploid establishment in nature. Because premating isolation is critical in order for neopolylpoids to avoid minority cytotype exclusion and thus facilitate establishment, we examined floral morphology and three common premating barriers to determine their importance in generating reproductive isolation of neopolyploids from diploids. METHODS We induced neopolyploidy in Trifolium pratense and compared their floral traits to the diploid progenitors. In addition to shifts in floral morphology, we examined three premating barriers: isolation by self-fertilization, flowering-time asynchrony, and pollinator-mediated isolation. RESULTS We found significant differences in the morphology of diploid and neopolyploid flowers, but these changes did not facilitate premating barriers that would generate reproductive isolation of neopolyploids from diploids. There was no difference in flowering phenology, pollinator visitation, or selfing between the cytotypes. CONCLUSIONS Our results indicate that barriers other than the ones tested in this study-such as geographic isolation, vegetative reproduction, and pistil-stigma incompatibilities-may be more important in facilitating isolation and establishment of neopolyploid T. pratense.
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Affiliation(s)
- Laura D Porturas
- Penn State University, Frost Entomological Museum, 501 ASI, University Park, Pennsylvania, 16802, USA
- Syracuse University, Biology, 107 College Place, Syracuse, New York, 13244, USA
| | - Kari A Segraves
- Syracuse University, Biology, 107 College Place, Syracuse, New York, 13244, USA
- Archbold Biological Station, 123 Main Drive, Venus, Florida, 33960, USA
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146
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Liu H, Zhou X, Li Q, Wang L, Xing Y. CCT domain-containing genes in cereal crops: flowering time and beyond. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2020; 133:1385-1396. [PMID: 32006055 DOI: 10.1007/s00122-020-03554-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/23/2020] [Indexed: 05/04/2023]
Abstract
The review summarizes the functions of the plant special transcription factors CCT family genes in multiple traits and discusses the molecular breeding strategies with CCT family genes in the future. Plants integrate circadian clock and external signals such as temperature and photoperiod to synchronize flowering with seasonal environmental changes. This process makes cereal crops including short-day crops, such as rice and maize, and long-day crops, such as wheat and barley, better adapt to varied growth zones from temperate to tropical regions. CCT family genes involve circadian clock and photoperiodic flowering pathways and help plants set a suitable flowering time to produce offspring. Beyond the flowering time, CCT family genes in cereal crops are associated with biomass and grain yield. Moreover, recent studies showed that they also associate with photosynthesis, nutrition use efficiency and stress tolerance. Here, we systematically review the progress in functional characterization of CCT family genes in flowering, geographical adaptation and grain yield formation, raise the core questions related to their molecular mechanisms and discuss how to practice them in genetic improvement in cereal crops by combining gene diagnosis and top-level design.
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Affiliation(s)
- Haiyang Liu
- College of Agriculture, Yangtze University, Jingzhou, 434000, China
| | - Xiangchun Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agriculture University, Wuhan, 430070, China
| | - Qiuping Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agriculture University, Wuhan, 430070, China
| | - Lei Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agriculture University, Wuhan, 430070, China
| | - Yongzhong Xing
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agriculture University, Wuhan, 430070, China.
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147
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Kuki Y, Ohno R, Yoshida K, Takumi S. Heterologous expression of wheat WRKY transcription factor genes transcriptionally activated in hybrid necrosis strains alters abiotic and biotic stress tolerance in transgenic Arabidopsis. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 150:71-79. [PMID: 32120271 DOI: 10.1016/j.plaphy.2020.02.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 01/22/2020] [Accepted: 02/20/2020] [Indexed: 06/10/2023]
Abstract
Hybrid necrosis and hybrid chlorosis are sometimes observed in interspecific hybrids between the tetraploid wheat cultivar Langdon and diploid wild wheat Aegilops tauschii. Many WRKY transcription factor genes are dramatically upregulated in necrosis and chlorosis wheat hybrids. Here, we isolated cDNA clones for four wheat WRKY transcription factor genes, TaWRKY49, TaWRKY92, TaWRKY112, and TaWRKY142, that were commonly upregulated in the hybrid necrosis and hybrid chlorosis and belonged to the same clade of the WRKY gene family. Expression patterns of the four TaWRKY genes in response to several stress conditions were similar in wheat seeding leaves. The four TaWRKY-GFP fusion proteins were targeted to the nucleus in onion epidermal cells. The TaWRKY gene expression levels were increased by high salt, dehydration, darkness, and blast fungus treatment in common wheat. Expression of either of the TaWRKY genes increased salinity and osmotic stress tolerance accompanied with overexpression of STZ/Zat10, and induced overexpression of the salicylic acid-signal pathway marker gene AtPR1 in transgenic Arabidopsis. TaWRKY142 expression also induced the jasmonic acid-pathway marker gene AtPDF1.2 and enhanced resistance against the fungal pathogen Colletotrichum higginsianum in transgenic Arabidopsis. These results suggest that the four TaWRKY genes act as integrated hubs of multiple stress signaling pathways in wheat and play important roles in autoimmune response-inducing hybrid necrosis and hybrid chlorosis.
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Affiliation(s)
- Yasunobu Kuki
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, Kobe, 657-8501, Japan
| | - Ryoko Ohno
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, Kobe, 657-8501, Japan.
| | - Kentaro Yoshida
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, Kobe, 657-8501, Japan
| | - Shigeo Takumi
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, Kobe, 657-8501, Japan.
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148
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MAT heterozygosity and the second sterility barrier in the reproductive isolation of Saccharomyces species. Curr Genet 2020; 66:957-969. [PMID: 32356035 PMCID: PMC7497327 DOI: 10.1007/s00294-020-01080-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/16/2020] [Accepted: 04/24/2020] [Indexed: 12/12/2022]
Abstract
The genetic analysis of large numbers of Saccharomyces cerevisiae × S. uvarum ("cevarum") and S. kudriavzevii × S. uvarum ("kudvarum") hybrids in our previous studies revealed that these species are isolated by a postzygotic double-sterility barrier. We proposed a model in which the first barrier is due to the abruption of the meiotic process by the failure of the chromosomes of the subgenomes to pair (and recombine) in meiosis and the second barrier is assumed to be the result of the suppression of mating by allospecific MAT heterozygosity. While the former is analogous to the major mechanism of postzygotic reproductive isolation in plants and animals, the latter seems to be Saccharomyces specific. To bolster the assumed involvement of MAT in the second sterility barrier, we produced synthetic alloploid two-species cevarum and kudvarum hybrids with homo- and heterothallic backgrounds as well as three-species S. cerevisiae × S. kudvarum × S. uvarum ("cekudvarum") hybrids by mass-mating and examined their MAT loci using species- and cassette-specific primer pairs. We found that the allospecific MAT heterozygosity repressed MAT switching and mating in the hybrids and in the viable but sterile spores produced by the cevarum hybrids that had increased (allotetraploid) genomes. The loss of heterozygosity by meiotic malsegregation of MAT-carrying chromosomes in the latter hybrids broke down the sterility barrier. The resulting spores nullisomic for the S. uvarum chromosome produced vegetative cells capable of MAT switching and conjugation, opening the way for GARMe (Genome Autoreduction in Meiosis), the process that leads to chimeric genomes.
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149
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Feng C, Yi H, Yang L, Kang M. The genetic basis of hybrid male sterility in sympatric Primulina species. BMC Evol Biol 2020; 20:49. [PMID: 32349663 PMCID: PMC7191819 DOI: 10.1186/s12862-020-01617-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 04/21/2020] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Sympatric sister species provide an opportunity to investigate the genetic mechanisms and evolutionary forces that maintain species boundaries. The persistence of morphologically and genetically distinct populations in sympatry can only occur if some degree of reproductive isolation exists. A pair of sympatric sister species of Primulina (P. depressa and P. danxiaensis) was used to explore the genetic architecture of hybrid male sterility. RESULTS We mapped one major- and seven minor-effect quantitative trait loci (QTLs) that underlie pollen fertility rate (PFR). These loci jointly explained 55.4% of the phenotypic variation in the F2 population. A Bateson-Dobzhansky-Muller (BDM) model involving three loci was observed in this system. We found genotypic correlations between hybrid male sterility and flower morphology, consistent with the weak but significant phenotypic correlations between PFR and floral traits. CONCLUSIONS Hybrid male sterility in Primulina is controlled by a polygenic genetic basis with a complex pattern. The genetic incompatibility involves a three-locus BDM model. Hybrid male sterility is genetically correlated with floral morphology and divergence hitchhiking may occur between them.
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Affiliation(s)
- Chen Feng
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650 China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650 China
| | - Huiqin Yi
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Lihua Yang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650 China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650 China
| | - Ming Kang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650 China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650 China
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Zhou Y, Li WW, Zhang YQ, Xing XC, Zhang JQ, Ren Y. Extensive reticulate evolution within Fargesia (s.l.) (Bambusoideae: Poaceae) and its allies: Evidence from multiple nuclear markers. Mol Phylogenet Evol 2020; 149:106842. [PMID: 32305509 DOI: 10.1016/j.ympev.2020.106842] [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: 09/01/2019] [Revised: 04/10/2020] [Accepted: 04/13/2020] [Indexed: 11/16/2022]
Abstract
Reticulate evolution resulting from hybridization and introgression has been recognized as a creative source of species and diversification in bamboos. Previous phylogenetic studies revealed that Fargesia (s.l.) (Fargesia and Yushania) was divided into the Fargesia spathe clade and the non-spathe clade. Interestingly, the Fargesia spathe clade may have originated from hybridization among other clades within Fargesia (s.l.). Understanding the hybrid origin of this clade requires a robust phylogenetic framework in which major clades within Fargesia (s.l.) are resolved. Here, we used three nuclear genes to reconstruct the evolutionary history of Fargesia (s.l.) and its allies to identify putative patterns in the origin of the Fargesia spathe clade and to examine the extent to which reticulate evolution has occurred at the interspecific level in bamboos. Bashania species form a clade with Fargesia (s.l.), which is further divided into Group I and Group II. The Fargesia spathe clade, the Alpine Bashania clade, and Fargesia yajiangensis comprise Group I, while the Bashania fargesii clade and the remaining Fargesia (s.l.) species form Group II. Incongruence between the current nuclear-based and previous plastid phylogenies demonstrate several possible hybridization events among Fargesia (s.l.) species and related taxa, which have given rise to the Fargesia spathe clade, the Phyllostachys clade, and the Ampelocalamus clade. We also detected several putative hybrid species of Fargesia (s.l.). Our results show that reticulate evolution has played a prominent role in Fargesia (s.l.) evolution, which could, in part, account for the taxonomic difficulty associated with Fargesia (s.l.) and the alpine bamboos. The study also underscores the importance of hybridization in the evolution of bamboos, at both intergeneric and intrageneric levels.
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Affiliation(s)
- Yun Zhou
- College of Life Sciences, Shaanxi Normal University, Xi'an 710119, China
| | - Wan-Wan Li
- College of Life Sciences, Shaanxi Normal University, Xi'an 710119, China
| | - Yu-Qu Zhang
- College of Life Sciences, Shaanxi Normal University, Xi'an 710119, China
| | - Xiao-Cheng Xing
- College of Life Sciences, Shaanxi Normal University, Xi'an 710119, China
| | - Jian-Qiang Zhang
- College of Life Sciences, Shaanxi Normal University, Xi'an 710119, China.
| | - Yi Ren
- College of Life Sciences, Shaanxi Normal University, Xi'an 710119, China
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