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Niccolò T, Anderson AW, Emidio A. Apomixis: oh, what a tangled web we have! PLANTA 2023; 257:92. [PMID: 37000270 PMCID: PMC10066125 DOI: 10.1007/s00425-023-04124-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 03/21/2023] [Indexed: 06/19/2023]
Abstract
Apomixis is a complex evolutionary trait with many possible origins. Here we discuss various clues and causes, ultimately proposing a model harmonizing the three working hypotheses on the topic. Asexual reproduction through seeds, i.e., apomixis, is the holy grail of plant biology. Its implementation in modern breeding could be a game-changer for agriculture. It has the potential to generate clonal crops and maintain valuable complex genotypes and their associated heterotic traits without inbreeding depression. The genetic basis and origins of apomixis are still unclear. There are three central hypothesis for the development of apomixis that could be: i) a deviation from the sexual developmental program caused by an asynchronous development, ii) environmentally triggered through epigenetic regulations (a polyphenism of sex), iii) relying on one or more genes/alleles. Because of the ever-increasing complexity of the topic, the path toward a detailed understanding of the mechanisms underlying apomixis remains unclear. Here, we discuss the most recent advances in the evolution perspective of this multifaceted trait. We incorporated our understanding of the effect of endogenous effectors, such as small RNAs, epigenetic regulation, hormonal pathways, protein turnover, and cell wall modification in response to an upside stress. This can be either endogenous (hybridization or polyploidization) or exogenous environmental stress, mainly due to oxidative stress and the corresponding ROS (Reacting Oxygen Species) effectors. Finally, we graphically represented this tangled web.
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Affiliation(s)
- Terzaroli Niccolò
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy.
| | - Aaron W Anderson
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy
- Fulbright Scholar From Department of Plant Sciences, University of California, Davis, USA
| | - Albertini Emidio
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy
- Consorzio Interuniversitario per le Biotecnologie (CIB), Trieste, Italy
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2
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Hörandl E. Geographical Parthenogenesis in Alpine and Arctic Plants. PLANTS (BASEL, SWITZERLAND) 2023; 12:844. [PMID: 36840192 PMCID: PMC9959270 DOI: 10.3390/plants12040844] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
The term "Geographical parthenogenesis" describes the phenomenon that asexual organisms usually occupy larger and more northern distribution areas than their sexual relatives, and tend to colonize previously glaciated areas. Several case studies on alpine and arctic plants confirm the geographical pattern, but the causal factors behind the phenomenon are still unclear. Research of the last decade in several plant families has shed light on the question and evaluated some of the classical evolutionary theories. Results confirmed, in general, that the advantages of uniparental reproduction enable apomictic plants to re-colonize faster in larger and more northern distribution areas. Associated factors like polyploidy seem to contribute mainly to the spatial separation of sexual and asexual cytotypes. Ecological studies suggest a better tolerance of apomicts to colder climates and temperate extremes, whereby epigenetic flexibility and phenotypic plasticity play an important role in occupying ecological niches under harsh conditions. Genotypic diversity appears to be of lesser importance for the distributional success of asexual plants. Classical evolutionary theories like a reduced pressure of biotic interactions in colder climates and hence an advantage to asexuals (Red Queen hypothesis) did not gain support from studies on plants. However, it is also still enigmatic why sexual outcrossing remains the predominant mode of reproduction also in alpine floras. Constraints for the origin of apomixis might play a role. Interestingly, some studies suggest an association of sexuality with abiotic stresses. Light stress in high elevations might explain why most alpine plants retain sexual reproduction despite other environmental factors that would favor apomixis. Directions for future research will be given.
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Affiliation(s)
- Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Goettingen, 37073 Göttingen, Germany
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3
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Hörandl E. Novel Approaches for Species Concepts and Delimitation in Polyploids and Hybrids. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11020204. [PMID: 35050093 PMCID: PMC8781807 DOI: 10.3390/plants11020204] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/07/2022] [Accepted: 01/10/2022] [Indexed: 05/08/2023]
Abstract
Hybridization and polyploidization are important processes for plant evolution. However, classification of hybrid or polyploid species has been notoriously difficult because of the complexity of processes and different evolutionary scenarios that do not fit with classical species concepts. Polyploid complexes are formed via combinations of allopolyploidy, autopolyploidy and homoploid hybridization with persisting sexual reproduction, resulting in many discrete lineages that have been classified as species. Polyploid complexes with facultative apomixis result in complicated net-work like clusters, or rarely in agamospecies. Various case studies illustrate the problems that apply to traditional species concepts to hybrids and polyploids. Conceptual progress can be made if lineage formation is accepted as an inevitable consequence of meiotic sex, which is established already in the first eukaryotes as a DNA restoration tool. The turnaround of the viewpoint that sex forms species as lineages helps to overcome traditional thinking of species as "units". Lineage formation and self-sustainability is the prerequisite for speciation and can also be applied to hybrids and polyploids. Species delimitation is aided by the improved recognition of lineages via various novel -omics methods, by understanding meiosis functions, and by recognizing functional phenotypes by considering morphological-physiological-ecological adaptations.
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Affiliation(s)
- Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Goettingen, 37073 Göttingen, Germany
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Syngelaki E, Paetzold C, Hörandl E. Gene Expression Profiles Suggest a Better Cold Acclimation of Polyploids in the Alpine Species Ranunculus kuepferi (Ranunculaceae). Genes (Basel) 2021; 12:genes12111818. [PMID: 34828424 PMCID: PMC8625111 DOI: 10.3390/genes12111818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/16/2021] [Accepted: 11/17/2021] [Indexed: 12/17/2022] Open
Abstract
Alpine habitats are shaped by harsh abiotic conditions and cold climates. Temperature stress can affect phenotypic plasticity, reproduction, and epigenetic profiles, which may affect acclimation and adaptation. Distribution patterns suggest that polyploidy seems to be advantageous under cold conditions. Nevertheless, whether temperature stress can induce gene expression changes in different cytotypes, and how the response is initialized through gene set pathways and epigenetic control remain vague for non-model plants. The perennial alpine plant Ranunculus kuepferi was used to investigate the effect of cold stress on gene expression profiles. Diploid and autotetraploid individuals were exposed to cold and warm conditions in climate growth chambers and analyzed via transcriptome sequencing and qRT-PCR. Overall, cold stress changed gene expression profiles of both cytotypes and induced cold acclimation. Diploids changed more gene set pathways than tetraploids, and suppressed pathways involved in ion/cation homeostasis. Tetraploids mostly activated gene set pathways related to cell wall and plasma membrane. An epigenetic background for gene regulation in response to temperature conditions is indicated. Results suggest that perennial alpine plants can respond to temperature extremes via altered gene expression. Tetraploids are better acclimated to cold conditions, enabling them to colonize colder climatic areas in the Alps.
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Affiliation(s)
- Eleni Syngelaki
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Georg-August-Universität Göttingen, 37073 Göttingen, Germany;
- Correspondence:
| | - Claudia Paetzold
- Department of Botany and Molecular Evolution, Senckenberg Research Institute, 60325 Frankfurt am Main, Germany;
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Georg-August-Universität Göttingen, 37073 Göttingen, Germany;
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Reichelt N, Wen J, Pätzold C, Appelhans MS. Target enrichment improves phylogenetic resolution in the genus Zanthoxylum (Rutaceae) and indicates both incomplete lineage sorting and hybridization events. ANNALS OF BOTANY 2021; 128:497-510. [PMID: 34250543 PMCID: PMC8414929 DOI: 10.1093/aob/mcab092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/09/2021] [Indexed: 05/14/2023]
Abstract
BACKGROUND AND AIMS Zanthoxylum is the only pantropical genus within Rutaceae, with a few species native to temperate eastern Asia and North America. Efforts using Sanger sequencing failed to resolve the backbone phylogeny of Zanthoxylum. In this study, we employed target-enrichment high-throughput sequencing to improve resolution. Gene trees were examined for concordance and sectional classifications of Zanthoxylum were evaluated. Off-target reads were investigated to identify putative single-copy markers for bait refinement, and low-copy markers for evidence of putative hybridization events. METHODS A custom bait set targeting 354 genes, with a median of 321 bp, was designed for Zanthoxylum and applied to 44 Zanthoxylum species and one Tetradium species as the outgroup. Illumina reads were processed via the HybPhyloMaker pipeline. Phylogenetic inferences were conducted using coalescent and maximum likelihood methods based on concatenated datasets. Concordance was assessed using quartet sampling. Additional phylogenetic analyses were performed on putative single and low-copy genes extracted from off-target reads. KEY RESULTS Four major clades are supported within Zanthoxylum: the African clade, the Z. asiaticum clade, the Asian-Pacific-Australian clade and the American-eastern Asian clade. While overall support has improved, regions of conflict are similar to those previously observed. Gene tree discordances indicate a hybridization event in the ancestor of the Hawaiian lineage, and incomplete lineage sorting in the American backbone. Off-target putative single-copy genes largely confirm on-target results, and putative low-copy genes provide additional evidence for hybridization in the Hawaiian lineage. Only two of the five sections of Zanthoxylum are resolved as monophyletic. CONCLUSIONS Target enrichment is suitable for assessing phylogenetic relationships in Zanthoxylum. Our phylogenetic analyses reveal that current sectional classifications need revision. Quartet tree concordance indicates several instances of reticulate evolution. Off-target reads are proven useful to identify additional phylogenetically informative regions for bait refinement or gene tree based approaches.
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Affiliation(s)
- Niklas Reichelt
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute of Plant Sciences, University of Goettingen, Untere Karspuele 2, 37073 Goettingen, Germany
- Department of Botany, National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, MRC 166, Washington, DC 20013-7012, USA
- Pharmaceutical Biology, Julius-von-Sachs-Institute for Biosciences, University of Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany
| | - Jun Wen
- Department of Botany, National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, MRC 166, Washington, DC 20013-7012, USA
| | - Claudia Pätzold
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute of Plant Sciences, University of Goettingen, Untere Karspuele 2, 37073 Goettingen, Germany
- Department Botany and Molecular Evolution, Senckenberg Research Institute and Natural History Museum Frankfurt, Senckenberganlage 25, 60325 Frankfurt am Main, Germany
| | - Marc S Appelhans
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute of Plant Sciences, University of Goettingen, Untere Karspuele 2, 37073 Goettingen, Germany
- Department of Botany, National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, MRC 166, Washington, DC 20013-7012, USA
- For correspondence. E-mail
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Zangiabadi S, Zaremaivan H, Brotons LI, Mostafavi H, Ranjbar H. Using climatic variables alone overestimate climate change impacts on predicting distribution of an endemic species. PLoS One 2021; 16:e0256918. [PMID: 34473770 PMCID: PMC8412407 DOI: 10.1371/journal.pone.0256918] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 08/18/2021] [Indexed: 11/25/2022] Open
Abstract
Plant species distribution is constrained by both dynamic and static environmental variables. However, relative contribution of dynamic and static variables in determining species distributions is not clear and has far reaching implications for range change dynamics in a changing world. Prunus eburnea (Spach) Aitch. & Hemsl. is an endemic and medicinal plant species of Iran. It has rendered itself as ecologically important for its functions and services and is currently in need of habitat conservation measures requiring investigation of future potential distribution range. We conducted sampling of 500 points that cover most of Iran plateau and recorded the P. eburnea presence and absence during the period 2015-2017. In this study, we evaluated impacts of using only climatic variables versus combined with topographic and edaphic variables on accuracy criteria and predictive ability of current and future habitat suitability of this species under climate change (CCSM4, RCP 2.6 in 2070) by generalized linear model and generalized boosted model. Models' performances were evaluated using area under the curve, sensitivity, specificity and the true skill statistic. Then, we evaluated here, driving environmental variables determining the distribution of P. eburnea by using principal component analysis and partitioning methods. Our results indicated that prediction with high accuracy of the spatial distribution of P. eburnea requires both climate information, as dynamic primary factors, but also detailed information on soil and topography variables, as static factors. The results emphasized that environmental variable grouping influenced the modelling prediction ability strongly and the use of only climate variables would exaggerate the predicted distribution range under climate change. Results supported using both dynamic and static variables improved accuracy of the modeling and provided more realistic prediction of species distribution under influence of climate change.
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Affiliation(s)
- Somayeh Zangiabadi
- Department of Plant Biology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Hassan Zaremaivan
- Department of Plant Biology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - LIuis Brotons
- CREAF, Cerdanyola del Vallès, Spain
- InForest Jru (CTFC-CREAF), Solsona, Spain
- CSIC, Cerdanyola del Vallès, Spain
| | - Hossein Mostafavi
- Department of Biodiversity and Ecosystem Management, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran
| | - Hojjatollah Ranjbar
- Department of Mining Engineering, Shahid Bahonar University of Kerman, Kerman, Iran
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7
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Meirmans PG. Niche divergence contributes to geographical parthenogenesis in two dandelion taxa. J Evol Biol 2021; 34:1071-1086. [PMID: 33955626 PMCID: PMC8362108 DOI: 10.1111/jeb.13794] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 03/29/2021] [Accepted: 04/25/2021] [Indexed: 12/11/2022]
Abstract
Many sexual-asexual complexes show a distinct pattern where the asexuals have larger and more northerly ranges than closely related sexuals. A prime candidate to explain this so-called "geographical parthenogenesis" is ecological niche divergence between the sexuals and asexuals. Modern niche modelling techniques allow testing niche divergence by directly comparing the niches of sexuals and asexuals. In this study, I use such techniques to perform range-wide tests of whether nine bioclimatic variables, including annual mean temperature and annual precipitation, contribute to geographical parthenogenesis in two dandelion taxa: Taraxacum section Ruderalia and Taraxacum section Erythrosperma, which are both comprised of sexual diploids and asexual triploids. For both sections, I found evidence of niche divergence, though the exact nature of this divergence was different for the two sections. In section Ruderalia, the sexuals preferred warmer and wetter conditions, whereas in section Erythrosperma, the sexuals preferred dryer conditions. Using Species Distribution Modelling, consistent differences between the sexuals and asexuals were found when looking at the niche determinants: the variables that are most important for modelling the distribution. Furthermore, and in contrast with theoretical expectations that predict that the sexuals should have a wider niche, in section Erythrosperma the asexuals were found to have a wider niche than the sexuals. In conclusion, differences in niche optima, niche determinants, and niche width all contribute to the pattern of geographical parthenogenesis of these two dandelion taxa. However, the results also indicate that the exact causation of geographical parthenogenesis is not uniform across taxa.
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Affiliation(s)
- Patrick G Meirmans
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Amsterdam, The Netherlands
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Karbstein K, Tomasello S, Hodač L, Lorberg E, Daubert M, Hörandl E. Moving beyond assumptions: Polyploidy and environmental effects explain a geographical parthenogenesis scenario in European plants. Mol Ecol 2021; 30:2659-2675. [PMID: 33871107 DOI: 10.1111/mec.15919] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 03/31/2021] [Accepted: 04/01/2021] [Indexed: 11/28/2022]
Abstract
Geographical parthenogenesis (GP) describes the phenomenon that apomicts tend to have larger distribution areas and/or occur at higher altitudes or latitudes compared to sexual relatives. However, the complex effects of genome-wide heterozygosity, ploidy, reproduction mode (sexual vs. apomictic), and environment shaping GP of plants are still not well understood. We ascertained ploidy and reproduction mode by flow cytometry of 221 populations, and added genomic RADseq data (maximum 33,165 loci) of 80 taxa of the Ranunculus auricomus polyploid plant complex in temperate Europe. We observed 7% mainly diploid sexual, 28% facultative apomictic (mean sexuality 7.1%), and 65% obligate apomictic populations. Sexuals occupied a more southern, smaller distribution area, whereas apomicts expanded their range to higher latitudes. Within the complex, we detected three main genetic clusters and highly reticulate relationships. A genetically-informed path analysis using GLMMs revealed several significant relationships. Sexuality of populations (percent of sexual seeds) was higher in diploids compared to polyploids, associated with more petals, and similar between forests and open habitats. In contrast to other apomictic plant complexes, sexuality was mainly positively correlated to solar radiation and isothermality, which fits the southern distribution. We found up to three times higher heterozygosity in polyploids compared to diploids, and generally more heterozygous individuals in forests compared with open habitats. Interestingly, we revealed a previously unknown positive association between heterozygosity and temperature seasonality, suggesting a higher resistance of polyploids to more extreme climatic conditions. We provide empirical evidence for intrinsic and extrinsic factors shaping the GP pattern in a polyploid plant complex.
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Affiliation(s)
- Kevin Karbstein
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Albrecht-von-Haller Institute for Plant Sciences, University of Göttingen, Göttingen, Germany.,Georg-August University School of Science (GAUSS), University of Göttingen, Göttingen, Germany
| | - Salvatore Tomasello
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Albrecht-von-Haller Institute for Plant Sciences, University of Göttingen, Göttingen, Germany
| | - Ladislav Hodač
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Albrecht-von-Haller Institute for Plant Sciences, University of Göttingen, Göttingen, Germany
| | - Ellen Lorberg
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Albrecht-von-Haller Institute for Plant Sciences, University of Göttingen, Göttingen, Germany
| | - Mareike Daubert
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Albrecht-von-Haller Institute for Plant Sciences, University of Göttingen, Göttingen, Germany.,Institute of Biology and Environmental Sciences, Carl von Ossietzky University, Oldenburg, Germany
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Albrecht-von-Haller Institute for Plant Sciences, University of Göttingen, Göttingen, Germany
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Wang P, Yang F, Ma Z, Zhang R. Chromosome Unipolar Division and Low Expression of Tws May Cause Parthenogenesis of Rice Water Weevil ( Lissorhoptrus oryzophilus Kuschel). INSECTS 2021; 12:278. [PMID: 33805047 PMCID: PMC8064085 DOI: 10.3390/insects12040278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 03/22/2021] [Accepted: 03/22/2021] [Indexed: 11/28/2022]
Abstract
Rice water weevil (RWW) is divided into two types of population, triploid parthenogenesis and diploid bisexual reproduction. In this study, we explored the meiosis of triploid parthenogenesis RWW (Shangzhuang Town, Haidian District, Beijing, China) by marking the chromosomes and microtubules of parthenogenetic RWW oocytes via immunostaining. The immunostaining results show that there is a canonical meiotic spindle formed in the triploid parthenogenetic RWW oocytes, but chromosomes segregate at only one pole, which means that there is a chromosomal unipolar division during the oogenesis of the parthenogenetic RWW. Furthermore, we cloned the conserved sequences of parthenogenetic RWW REC8 and Tws, and designed primers based on the parthenogenetic RWW sequence to detect expression patterns by quantitative PCR (Q-PCR). Q-PCR results indicate that the expression of REC8 and Tws in ovarian tissue of bisexual Drosophila melanogaster is 0.98 and 10,000.00 times parthenogenetic RWW, respectively (p < 0.01). The results show that Tws had low expression in parthenogenetic RWW ovarian tissue, and REC8 was expressed normally. Our study suggests that the chromosomal unipolar division and deletion of Tws may cause parthenogenesis in RWW.
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Affiliation(s)
- Pengcheng Wang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (P.W.); (F.Y.); (Z.M.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fangyuan Yang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (P.W.); (F.Y.); (Z.M.)
- Department of Entomology, Guizhou University, Guiyang 550025, Guizhou, China
| | - Zhuo Ma
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (P.W.); (F.Y.); (Z.M.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Runzhi Zhang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (P.W.); (F.Y.); (Z.M.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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10
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Karbstein K, Rahmsdorf E, Tomasello S, Hodač L, Hörandl E. Breeding system of diploid sexuals within the Ranunculus auricomus complex and its role in a geographical parthenogenesis scenario. Ecol Evol 2020; 10:14435-14450. [PMID: 33391726 PMCID: PMC7771175 DOI: 10.1002/ece3.7073] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 11/06/2020] [Accepted: 11/09/2020] [Indexed: 12/26/2022] Open
Abstract
The larger distribution area of asexuals compared with their sexual relatives in geographical parthenogenesis (GP) scenarios has been widely attributed to the advantages of uniparental reproduction and polyploidy. However, potential disadvantages of sexuals due to their breeding system have received little attention so far. Here, we study the breeding system of five narrowly distributed sexual lineages of Ranunculus notabilis s.l. (R. auricomus complex) and its effects on outcrossing, inbreeding, female fitness, and heterozygosity. We performed selfing and intra- and interlineage crossings by bagging 481 flowers (59 garden individuals) followed by germination experiments. We compared seed set and germination rates, and related them to genetic distance and genome-wide heterozygosity (thousands of RADseq loci). Selfings (2.5%) unveiled a significantly lower seed set compared with intra- (69.0%) and interlineage crossings (69.5%). Seed set of intra- (65%) compared to interpopulation crossings (78%) was significantly lower. In contrast, all treatments showed comparable germination rates (32%-43%). Generalized linear regressions between seed set and genetic distance revealed positive relationships in general and between lineages, and a negative one within lineages. Seed set was the main decisive factor for female fitness. Germination rates were not related to genetic distance at any level, but were positively associated with heterozygosity in interlineage crossings. Experiments confirmed full crossability and predominant outcrossing among sexual R. notabilis s.l. lineages. However, up to 5% (outliers 15%-31%) of seeds were formed by selfing, probably due to semi-self-compatibility in a multi-locus gametophytic SI system. Less seed set in intrapopulation crossings, and higher seed set and germination rates from crossings of genetically more distant and heterozygous lineages (interlineage) indicate negative inbreeding and positive outbreeding effects. In GP scenarios, sexual species with small and/or isolated populations can suffer from decreased female fitness due to their breeding system. This factor, among others, probably limits range expansion of sexuals.
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Affiliation(s)
- Kevin Karbstein
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium)Institute for Plant SciencesUniversity of GöttingenGöttingenGermany
- Georg‐August University School of Science (GAUSS)University of GöttingenGöttingenGermany
| | - Elisabeth Rahmsdorf
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium)Institute for Plant SciencesUniversity of GöttingenGöttingenGermany
- Institute of BiologyLeipzig UniversityLeipzigGermany
| | - Salvatore Tomasello
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium)Institute for Plant SciencesUniversity of GöttingenGöttingenGermany
| | - Ladislav Hodač
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium)Institute for Plant SciencesUniversity of GöttingenGöttingenGermany
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium)Institute for Plant SciencesUniversity of GöttingenGöttingenGermany
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11
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Morgan EJ, Čertner M, Lučanová M, Kubíková K, Marhold K, Kolář F. Niche similarity in diploid-autotetraploid contact zones of Arabidopsis arenosa across spatial scales. AMERICAN JOURNAL OF BOTANY 2020; 107:1375-1388. [PMID: 32974906 DOI: 10.1002/ajb2.1534] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/21/2020] [Indexed: 06/11/2023]
Abstract
PREMISE Whole genome duplication is a major evolutionary event, but its role in ecological divergence remains equivocal. When populations of different ploidy (cytotypes) overlap in space, "contact zones" are formed, allowing the study of evolutionary mechanisms contributing toward ploidy divergence. Multiple contact zones per species' range are often described but rarely leveraged as natural replicates. We explored whether the strength of niche differentiation of diploid and autotetraploid Arabidopsis arenosa varies over distinct contact zones and if the frequency of triploids decreases from seedling to adult stage. METHODS We characterized ploidy composition and habitat preferences in 264 populations across three contact zones using climatic niche modeling. Ecological differences of cytotypes were also assessed using local vegetation surveys at 110 populations within two contact zones, and at the finer scale within five mixed-ploidy sites. This was complemented by flow cytometry of seedlings. RESULTS We found no niche differences between diploid and tetraploid populations within contact zones for either climatic or local environmental variables. Comparisons of cytotypes within mixed-ploidy sites found weak niche differences that were inconsistent in direction. Triploid individuals were virtually absent (0.14%) in the field, and they were at a similarly low frequency (0.2%) in ex situ germinated seedlings. CONCLUSIONS This study demonstrates the strength in investigating different spatial scales across several contact zones when addressing ecological niche differentiation between ploidies. The lack of consistent habitat differentiation of ploidies across the scales and locations supports the recently emerging picture that processes other than ecological differentiation may underlie ploidy coexistence in diploid-autopolyploid systems.
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Affiliation(s)
- Emma J Morgan
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
| | - Martin Čertner
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
| | - Magdalena Lučanová
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská 31, CZ-370 05, České Budějovice, Czech Republic
| | - Kateřina Kubíková
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
| | - Karol Marhold
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23, Bratislava, Slovak Republic
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
- Institute of Botany, University of Innsbruck, Sternwartestrasse 15, AT-6020, Innsbruck, Austria
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12
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Syngelaki E, Daubert M, Klatt S, Hörandl E. Phenotypic Responses, Reproduction Mode and Epigenetic Patterns under Temperature Treatments in the Alpine Plant Species Ranunculus kuepferi (Ranunculaceae). BIOLOGY 2020; 9:E315. [PMID: 33003474 PMCID: PMC7600421 DOI: 10.3390/biology9100315] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/18/2020] [Accepted: 09/26/2020] [Indexed: 12/04/2022]
Abstract
Plant life in alpine habitats is shaped by harsh abiotic conditions and cold climates. Phenotypic variation of morphological characters and reproduction can be influenced by temperature stress. Nevertheless, little is known about the performance of different cytotypes under cold stress and how epigenetic patterns could relate to phenotypic variation. Ranunculus kuepferi, a perennial alpine plant, served as a model system for testing the effect of cold stress on phenotypic plasticity, reproduction mode, and epigenetic variation. Diploid and autotetraploid individuals were placed in climate growth cabinets under warm and cold conditions. Morphological traits (height, leaves and flowers) and the proportion of well-developed seeds were measured as fitness indicators, while flow cytometric seed screening (FCSS) was utilized to determine the reproduction mode. Subsequently, comparisons with patterns of methylation-sensitive amplified fragment-length polymorphisms (AFLPs) were conducted. Diploids grew better under warm conditions, while tetraploids performed better in cold treatments. Epigenetic patterns were correlated with the expressed morphological traits. Cold stress reduced the reproduction fitness but did not induce apomixis in diploids. Overall, our study underlines the potential of phenotypic plasticity for acclimation under environmental conditions and confirms the different niche preferences of cytotypes in natural populations. Results help to understand the pattern of geographical parthenogenesis in the species.
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Affiliation(s)
- Eleni Syngelaki
- Albrecht-von-Haller-Institute for Plant Sciences, Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Georg-August-Universität Göttingen, 37073 Göttingen, Germany;
| | - Mareike Daubert
- Institute of Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, 26129 Oldenburg, Germany;
| | - Simone Klatt
- Section Safety and Environmental Protection, Georg-August-Universität Göttingen, 37073 Göttingen, Germany;
| | - Elvira Hörandl
- Albrecht-von-Haller-Institute for Plant Sciences, Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Georg-August-Universität Göttingen, 37073 Göttingen, Germany;
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13
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Nardi FD, Hülber K, Moser D, Alonso‐Marcos H, Tribsch A, Dobeš C. Occurrence of apomictic conspecifics and ecological preferences rather than colonization history govern the geographic distribution of sexual Potentilla puberula. Ecol Evol 2020; 10:7306-7319. [PMID: 32760530 PMCID: PMC7391561 DOI: 10.1002/ece3.6455] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/20/2020] [Accepted: 05/11/2020] [Indexed: 11/24/2022] Open
Abstract
The geographic distribution of sexual-apomictic taxa (i.e., comprising individuals usually reproducing either sexually or asexually via seeds) is traditionally thought to be driven by their ecological preferences and colonization histories. Where sexuals and apomicts get into contact with each other, competitive and reproductive interactions can interfere with these factors, an aspect which hitherto received little attention in biogeographic studies. We disentangled and quantified the relative effects of the three factors on the distribution of tetraploid sexuals in Potentilla puberula in a latitudinal transect through the Eastern European Alps, in which they are codistributed with penta-, hepta-, and octoploid apomictic conspecifics. Effects were explored by means of binomial generalized linear regression models combining a single with a multiple predictor approach. Postglacial colonization history was inferred from population genetic variation (AFLPs and cpDNA) and quantified using a cost distance metric. The study was based on 235 populations, which were purely sexual, purely apomictic, or of mixed reproductive mode. The occurrence of apomicts explained most of the variation in the distribution of sexuals (31%). Specifically, the presence of sexual tetraploids was negatively related to the presence of each of the three apomictic cytotypes. Effects of ecological preferences were substantial too (7% and 12% of the total variation explained by ecological preferences alone, or jointly with apomicts' occurrence, respectively). In contrast, colonization history had negligible effects on the occurrence of sexuals. Taken together, our results highlight the potentially high impact of reproductive interactions on the geographic distribution of sexual and apomictic conspecifics and that resultant mutual exclusion interrelates to ecological differentiation, a situation potentially promoting their local coexistence.
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Affiliation(s)
- Flavia Domizia Nardi
- Department of Forest GeneticsAustrian Research Centre for ForestsViennaAustria
- Department of BiosciencesUniversity of SalzburgSalzburgAustria
| | - Karl Hülber
- Department of Conservation Biology, Vegetation Ecology and Landscape EcologyUniversity of ViennaViennaAustria
| | - Dietmar Moser
- Department of Conservation Biology, Vegetation Ecology and Landscape EcologyUniversity of ViennaViennaAustria
| | - Henar Alonso‐Marcos
- Department of Forest GeneticsAustrian Research Centre for ForestsViennaAustria
- Department of Conservation Biology, Vegetation Ecology and Landscape EcologyUniversity of ViennaViennaAustria
| | - Andreas Tribsch
- Department of BiosciencesUniversity of SalzburgSalzburgAustria
| | - Christoph Dobeš
- Department of Forest GeneticsAustrian Research Centre for ForestsViennaAustria
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14
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Yu R, Huang J, Xu Y, Ding Y, Zang R. Plant Functional Niches in Forests Across Four Climatic Zones: Exploring the Periodic Table of Niches Based on Plant Functional Traits. FRONTIERS IN PLANT SCIENCE 2020; 11:841. [PMID: 32625227 PMCID: PMC7311788 DOI: 10.3389/fpls.2020.00841] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 05/26/2020] [Indexed: 06/11/2023]
Abstract
Previous studies have indicated that a niche variation scheme, similar to the periodic table of elements, can be constructed based on functional traits. The periodic table of niches for species is defined as a multidimensional ordination scheme of niche relationships and their orders in a specific biotic community. Comparing functional trait-based niches is extremely useful in theoretical studies of plant ecological strategies, community assembly, and the geographic differentiation of biomes across different climatic zones. Here, data for 11 functional traits belonging to three fundamental niche dimensions (leaf economy, mechanical support, and reproductive phenology) were compiled for 215 woody species from forests across four climatic zones (tropical, subtropical, warm-temperate, and cold-temperate). We constructed the periodic table of niches based on the functional traits of plants in different communities and explored their variations among biomes. A principal component analysis (PCA) was performed to derive the dominant gradients of trait combinations for each individual niche dimensional dataset. Then species scores for the first two axes (PC1 and PC2) were used as inputs for a second PCA to ordinate species in the continuous niche space constrained by the three niche dimensions. Changes in the functional niches of plants from the four biomes along the PC1 and PC2 of niche space were examined based on species scores. Leaf economy was the dominant functional dimension in the plant niche space, followed by mechanical support. Considerable niche convergences among different species were found in the niche space for each biome, except cold-temperate forest. The species niches varied mainly with the increasing specific leaf area/decreasing stem tissue density along PC1, and with the decrease of leaf area/plant size along PC2 from tropical to temperate forests, suggesting that the ecological strategies of plants in the four biomes changed from conservative to acquisitive with an increase in latitude. Our results confirmed that the periodic table of niches does exist and can be constructed by major functional dimensions composed of dominant functional traits. The periodic table of niches effectively reflects the changes of ecological strategies of plant species in biomes across different climatic zones.
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Affiliation(s)
- Ruoyun Yu
- Key Laboratory of Forest Ecology and Environment, State Forestry and Grassland Administration, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Jihong Huang
- Key Laboratory of Forest Ecology and Environment, State Forestry and Grassland Administration, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Yue Xu
- Key Laboratory of Forest Ecology and Environment, State Forestry and Grassland Administration, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Yi Ding
- Key Laboratory of Forest Ecology and Environment, State Forestry and Grassland Administration, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Runguo Zang
- Key Laboratory of Forest Ecology and Environment, State Forestry and Grassland Administration, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
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15
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Tomasello S, Karbstein K, Hodač L, Paetzold C, Hörandl E. Phylogenomics unravels Quaternary vicariance and allopatric speciation patterns in temperate‐montane plant species: A case study on the
Ranunculus auricomus
species complex. Mol Ecol 2020; 29:2031-2049. [DOI: 10.1111/mec.15458] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 04/21/2020] [Indexed: 01/06/2023]
Affiliation(s)
- Salvatore Tomasello
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium) Albrecht‐von‐Haller Institute for Plant Sciences University of Goettingen Göttingen Germany
| | - Kevin Karbstein
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium) Albrecht‐von‐Haller Institute for Plant Sciences University of Goettingen Göttingen Germany
- Georg‐August University School of Science (GAUSS) University of Goettingen Goettingen Germany
| | - Ladislav Hodač
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium) Albrecht‐von‐Haller Institute for Plant Sciences University of Goettingen Göttingen Germany
| | - Claudia Paetzold
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium) Albrecht‐von‐Haller Institute for Plant Sciences University of Goettingen Göttingen Germany
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium) Albrecht‐von‐Haller Institute for Plant Sciences University of Goettingen Göttingen Germany
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16
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Schinkel CCF, Syngelaki E, Kirchheimer B, Dullinger S, Klatt S, Hörandl E. Epigenetic Patterns and Geographical Parthenogenesis in the Alpine Plant Species Ranunculus kuepferi (Ranunculaceae). Int J Mol Sci 2020; 21:E3318. [PMID: 32392879 PMCID: PMC7247541 DOI: 10.3390/ijms21093318] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 12/31/2022] Open
Abstract
Polyploidization and the shift to apomictic reproduction are connected to changes in DNA cytosine-methylation. Cytosine-methylation is further sensitive to environmental conditions. We, therefore, hypothesize that DNA methylation patterns would differentiate within species with geographical parthenogenesis, i.e., when diploid sexual and polyploid apomictic populations exhibit different spatial distributions. On natural populations of the alpine plant Ranunculus kuepferi, we tested differences in methylation patterns across two cytotypes (diploid, tetraploid) and three reproduction modes (sexual, mixed, apomictic), and their correlation to environmental data and geographical distributions. We used methylation-sensitive amplified fragment-length polymorphism (methylation-sensitive AFLPs) and scored three types of epiloci. Methylation patterns differed independently between cytotypes versus modes of reproduction and separated three distinct combined groups (2x sexual + mixed, 4x mixed, and 4x apomictic), with differentiation of 4x apomicts in all epiloci. We found no global spatial autocorrelation, but instead correlations to elevation and temperature gradients in 22 and 36 epiloci, respectively. Results suggest that methylation patterns in R. kuepferi were altered by cold conditions during postglacial recolonization of the Alps, and by the concomitant shift to facultative apomixis, and by polyploidization. Obligate apomictic tetraploids at the highest elevations established a distinct methylation profile. Methylation patterns reflect an ecological gradient rather than the geographical differentiation.
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Affiliation(s)
- Christoph C. F. Schinkel
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Goettingen, Untere Karspüle 2, 37073 Göttingen, Germany;
| | - Eleni Syngelaki
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Goettingen, Untere Karspüle 2, 37073 Göttingen, Germany;
| | - Bernhard Kirchheimer
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria; (B.K.); (S.D.)
| | - Stefan Dullinger
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria; (B.K.); (S.D.)
| | - Simone Klatt
- Section Safety and Environmental Protection, University of Goettingen, Humboldtallee 15, 37073 Göttingen, Germany;
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Goettingen, Untere Karspüle 2, 37073 Göttingen, Germany;
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17
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Syngelaki E, Schinkel CCF, Klatt S, Hörandl E. Effects of Temperature Treatments on Cytosine-Methylation Profiles of Diploid and Autotetraploid Plants of the Alpine Species Ranunculus kuepferi (Ranunculaceae). FRONTIERS IN PLANT SCIENCE 2020; 11:435. [PMID: 32322263 PMCID: PMC7158262 DOI: 10.3389/fpls.2020.00435] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 03/25/2020] [Indexed: 05/23/2023]
Abstract
The exposure to environmental stress can trigger epigenetic variation, which may have several evolutionary consequences. Polyploidy seems to affect the DNA methylation profiles. Nevertheless, it abides unclear whether temperature stress can induce methylations changes in different cytotypes and to what extent a treatment shift is translated to an epigenetic response. A suitable model system for studying these questions is Ranunculus kuepferi, an alpine perennial herb. Diploid and autotetraploid individuals of R. kuepferi were exposed to cold (+7°C day/+2°C night; frost treatment -1°C cold shocks for 3 nights per week) and warm (+15° day/+10°C night) conditions in climate growth chambers for two consecutive flowering periods and shifted from one condition to the other after the first flowering period. Methylation-sensitive amplified fragment-length polymorphism markers were applied for both years, to track down possible alterations induced by the stress treatments. Patterns of methylation suggested that cytotypes differed significantly in their profiles, independent from year of treatment. Likewise, the treatment shift had an impact on both cytotypes, resulting in significantly less epiloci, regardless the shift's direction. The AMOVAs revealed higher variation within than among treatments in diploids. In tetraploids, internally-methylated loci had a higher variation among than within treatments, as a response to temperature's change in both directions, and support the hypothesis of temperature stress affecting the epigenetic variation. Results suggest that the temperature-sensitivity of DNA methylation patterns shows a highly dynamic phenotypic plasticity in R. kuepferi, as both cytotypes responded to temperature shifts. Furthermore, ploidy level, even without effects of hybridization, has an important effect on epigenetic background variation, which may be correlated with the DNA methylation dynamics during cold acclimation.
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Affiliation(s)
- Eleni Syngelaki
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Christoph C. F. Schinkel
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Simone Klatt
- Section Safety and Environmental Protection, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-Universität Göttingen, Göttingen, Germany
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18
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Abstract
Gametophytic apomixis is a way of asexual plant reproduction by seeds. It should be advantageous under stressful high altitude or latitude environment where short growing seasons, low temperatures, low pollinator activity or unstable weather may hamper sexual reproduction. However, this hypothesis remains largely untested. Here, we assess the reproductive mode in 257 species belonging to 45 families from the world’s broadest alpine belt (2800–6150 m) in NW Himalayas using flow cytometric seed screen. We found only 12 apomictic species, including several members of Poaceae (Festuca, Poa and Stipa), Rosaceae (Potentilla) and Ranunculaceae (Halerpestes, Ranunculus), which are families typical for high apomict frequency. However, several apomictic species were newly discovered, including the first known apomictic species from the family Biebersteiniaceae (Biebersteinia odora), and first apomicts from the genera Stipa (Stipa splendens) and Halerpestes (Halerpestes lancifolia). Apomicts showed no preference for higher elevations, even in these extreme Himalayan alpine habitats. Additional trait-based analyses revealed that apomicts differed from sexuals in comprising more rhizomatous graminoids and forbs, higher soil moisture demands, sharing the syndrome of dominant species with broad geographical and elevation ranges typical for the late-successional habitats. Apomicts differ from non-apomicts in greater ability of clonal propagation and preference for wetter, more productive habitats.
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19
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Albertini E, Barcaccia G, Carman JG, Pupilli F. Did apomixis evolve from sex or was it the other way around? JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2951-2964. [PMID: 30854543 DOI: 10.1093/jxb/erz109] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 02/25/2019] [Indexed: 05/20/2023]
Abstract
In angiosperms, there are two pathways of reproduction through seeds: sexual, or amphimictic, and asexual, or apomictic. The essential feature of apomixis is that an embryo in an ovule is formed autonomously. It may form from a cell of the nucellus or integuments in an otherwise sexual ovule, a process referred to as adventitious embryony. Alternatively, the embryo may form by parthenogenesis from an unreduced egg that forms in an unreduced embryo sac. The latter may form from an ameiotic megasporocyte, in which case it is referred to as diplospory, or from a cell of the nucellus or integument, in which case it is referred to as apospory. Progeny of apomictic plants are generally identical to the mother plant. Apomixis has been seen over the years as either a gain- or loss-of-function over sexuality, implying that the latter is the default condition. Here, we consider an additional point of view, that apomixis may be anciently polyphenic with sex and that both reproductive phenisms involve anciently canalized components of complex molecular processes. This polyphenism viewpoint suggests that apomixis fails to occur in obligately sexual eukaryotes because genetic or epigenetic modifications have silenced the primitive sex apomixis switch and/or disrupted molecular capacities for apomixis. In eukaryotes where sex and apomixis are clearly polyphenic, apomixis exponentially drives clonal fecundity during reproductively favorable conditions, while stress induces sex for stress-tolerant spore or egg formation. The latter often guarantees species survival during environmentally harsh seasons.
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Affiliation(s)
- Emidio Albertini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, Italy
| | - Gianni Barcaccia
- Laboratory of Genomics, Department of Agronomy, Food, Natural Resources, Animals and the Environment (DAFNAE), University of Padova Legnaro, PD, Italy
| | - John G Carman
- Department of Plants, Soils and Climate, Utah State University, Logan, Utah, USA
| | - Fulvio Pupilli
- Institute of Biosciences and Bioresources, Research Division of Perugia, National Research Council (CNR), Perugia, Italy
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20
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Hojsgaard D, Hörandl E. The Rise of Apomixis in Natural Plant Populations. FRONTIERS IN PLANT SCIENCE 2019; 10:358. [PMID: 31001296 PMCID: PMC6454013 DOI: 10.3389/fpls.2019.00358] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 03/07/2019] [Indexed: 05/04/2023]
Abstract
Apomixis, the asexual reproduction via seed, has many potential applications for plant breeding by maintaining desirable genotypes over generations. Since most major crops do not express natural apomixis, it is useful to understand the origin and maintenance of apomixis in natural plant systems. Here, we review the state of knowledge on origin, establishment and maintenance of natural apomixis. Many studies suggest that hybridization, either on diploid or polyploid cytotypes, is a major trigger for the formation of unreduced female gametophytes, which represents the first step toward apomixis, and must be combined to parthenogenesis, the development of an unfertilized egg cell. Nevertheless, fertilization of endosperm is still needed for most apomictic plants. Coupling of these three steps appears to be a major constraint for shifts to natural apomixis. Adventitious embryony is another developmental pathway toward apomixis. Establishment of a newly arisen apomictic lineage is often fostered by side-effects of polyploidy. Polyploidy creates an immediate reproductive barrier against the diploid parental and progenitor populations; it can cause a breakdown of genetic self-incompatibility (SI) systems which is needed to establish self-fertility of pseudogamous apomictic lineages; and finally, polyploidy could indirectly help to establish an apomictic cytotype in a novel ecological niche by increasing adaptive potentials of the plants. This step may be followed by a phase of diversification and range expansion, mostly described as geographical parthenogenesis. The utilization of apomixis in crops must consider the potential risks of pollen transfer and introgression into sexual crop fields, which might be overcome by using pollen-sterile or cleistogamous variants. Another risk is the escape into natural vegetation and potential invasiveness of apomictic plants which needs careful management and consideration of ecological conditions.
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21
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Kaushal P, Dwivedi KK, Radhakrishna A, Srivastava MK, Kumar V, Roy AK, Malaviya DR. Partitioning Apomixis Components to Understand and Utilize Gametophytic Apomixis. FRONTIERS IN PLANT SCIENCE 2019; 10:256. [PMID: 30906306 PMCID: PMC6418048 DOI: 10.3389/fpls.2019.00256] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 02/18/2019] [Indexed: 05/07/2023]
Abstract
Apomixis is a method of reproduction to generate clonal seeds and offers tremendous potential to fix heterozygosity and hybrid vigor. The process of apomictic seed development is complex and comprises three distinct components, viz., apomeiosis (leading to formation of unreduced egg cell), parthenogenesis (development of embryo without fertilization) and functional endosperm development. Recently, in many crops, these three components are reported to be uncoupled leading to their partitioning. This review provides insight into the recent status of our understanding surrounding partitioning apomixis components in gametophytic apomictic plants and research avenues that it offers to help understand the biology of apomixis. Possible consequences leading to diversity in seed developmental pathways, resources to understand apomixis, inheritance and identification of candidate gene(s) for partitioned components, as well as contribution towards creation of variability are all discussed. The potential of Panicum maximum, an aposporous crop, is also discussed as a model crop to study partitioning principle and effects. Modifications in cytogenetic status, as well as endosperm imprinting effects arising due to partitioning effects, opens up new opportunities to understand and utilize apomixis components, especially towards synthesizing apomixis in crops.
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Affiliation(s)
- Pankaj Kaushal
- ICAR-National Institute of Biotic Stress Management, Raipur, India
| | | | | | | | - Vinay Kumar
- ICAR-National Institute of Biotic Stress Management, Raipur, India
| | - Ajoy Kumar Roy
- ICAR-Indian Grassland and Fodder Research Institute, Jhansi, India
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22
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Nardi FD, Dobeš C, Müller D, Grasegger T, Myllynen T, Alonso-Marcos H, Tribsch A. Sexual intraspecific recombination but not de novo origin governs the genesis of new apomictic genotypes in Potentilla puberula (Rosaceae). TAXON 2018; 67:1108-1131. [PMID: 30799883 PMCID: PMC6382066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Apomixis - asexual reproduction via seeds - might arise de novo following polyploidisation events, or via reproductive transfer of apomixis. Both processes can be obtained within species or via hybridisation. We aimed to determine the origin of apomictic genotypes in Potentilla puberula, a rosaceous species showing reproductive differentiation with ploidy: sexual tetraploids and apomictic penta- to octoploids, which regularly co-occur in sympatry. The study is based on 726 individuals, comprising all cytotypes, collected from 138 populations in the Eastern European Alps. We established relationships of cytotypes based on AFLP fingerprinting and cpDNA sequencing to test (1) whether the apomicts are of recurrent allopolyploid origin or originated from within the species via autopolyploidy, and (2) whether there are indications for reproductive transfer versus de novo origin of apomixis. Three principal pathways were identified which explain the origin of new apomictic genotypes, all involving at least one apomictic parent and thus compatible with the idea of reproductive transfer of the apomictic trait to the progeny: (1) self-fertilisation of unreduced egg cells in apomicts; (2) cross-fertilisation among apomicts; and (3) occasionally, heteroploid crosses among sexuals and apomicts. Autopolyploids derived from tetraploid sexuals were repeatedly observed, but did not express apomixis. Finally, our results suggest no role of other species in the origin of extant apomictic genotypes of P. puberula, although local hybrids with P. crantzii were identified. In conclusion, our results show that the formation of new apomictic genotypes required a genetic contribution from at least one apomictic parent. This finding is in accordance with the idea that apomixis is inheritable in P. puberula. On the contrary, lack of apomixis in penta- and hexaploids derived from sexual backgrounds did not support the hypothesis of a de novo origin of apomixis. Relatively high frequency of remnant sexuality in the apomicts involving different cytological pathways of seed formation can explain their high cytological and genotypic diversity. Finally, lack of global introgression from a third taxon is in support of P. puberula as a concise, although highly diverse, species.
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Affiliation(s)
- Flavia Domizia Nardi
- Austrian Research Centre for Forests, Department of Forest Genetics, Seckendorff-Gudent-Weg 8, 1131 Vienna, Austria
- University of Salzburg, Department of Biosciences, Hellbrunnerstraße 34, 5020 Salzburg, Austria
| | - Christoph Dobeš
- Austrian Research Centre for Forests, Department of Forest Genetics, Seckendorff-Gudent-Weg 8, 1131 Vienna, Austria
| | - Dorothee Müller
- University of Salzburg, Department of Biosciences, Hellbrunnerstraße 34, 5020 Salzburg, Austria
| | - Tobias Grasegger
- University of Salzburg, Department of Biosciences, Hellbrunnerstraße 34, 5020 Salzburg, Austria
| | - Tuuli Myllynen
- Austrian Research Centre for Forests, Department of Forest Genetics, Seckendorff-Gudent-Weg 8, 1131 Vienna, Austria
| | - Henar Alonso-Marcos
- Austrian Research Centre for Forests, Department of Forest Genetics, Seckendorff-Gudent-Weg 8, 1131 Vienna, Austria
| | - Andreas Tribsch
- University of Salzburg, Department of Biosciences, Hellbrunnerstraße 34, 5020 Salzburg, Austria
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