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Wang Y, Fuentes RR, van Rengs WMJ, Effgen S, Zaidan MWAM, Franzen R, Susanto T, Fernandes JB, Mercier R, Underwood CJ. Harnessing clonal gametes in hybrid crops to engineer polyploid genomes. Nat Genet 2024; 56:1075-1079. [PMID: 38741016 PMCID: PMC11176054 DOI: 10.1038/s41588-024-01750-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 04/09/2024] [Indexed: 05/16/2024]
Abstract
Heterosis boosts crop yield; however, harnessing additional progressive heterosis in polyploids is challenging for breeders. We bioengineered a 'mitosis instead of meiosis' (MiMe) system that generates unreduced, clonal gametes in three hybrid tomato genotypes and used it to establish polyploid genome design. Through the hybridization of MiMe hybrids, we generated '4-haplotype' plants that encompassed the complete genetics of their four inbred grandparents, providing a blueprint for exploiting polyploidy in crops.
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Affiliation(s)
- Yazhong Wang
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Roven Rommel Fuentes
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Willem M J van Rengs
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Sieglinde Effgen
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | | | - Rainer Franzen
- Central Microscopy (CeMic), Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Tamara Susanto
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | | | - Raphael Mercier
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Charles J Underwood
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
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Ma R, Hu Z, Tian L, Zheng G, Wang Y, Chen X, Lou M, Gong M, Wang B, Yang F, Dong J, Zhang Y. Numerical and experimental analysis of pollen inhalation exposure in nasal airways following various middle turbinectomy. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 907:168156. [PMID: 37898207 DOI: 10.1016/j.scitotenv.2023.168156] [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: 06/26/2023] [Revised: 10/24/2023] [Accepted: 10/25/2023] [Indexed: 10/30/2023]
Abstract
BACKGROUND Middle turbinectomy (MT) has always been controversial. MT significantly alters the anatomy and redistributes the inhaled air. The current study is designed to quantify the effect of MT with varying resection volumes on airflow and associated pollen inhalation exposure characteristics in the nasal airways. METHODS Six realistic models following bilateral comprehensive Functional Endoscopic Sinus Surgery (FESS) deriving from CT images were constructed and their corresponding post-MT models with four types of MT procedures were virtually conducted. Inhalation exposure to pollen particles was simulated by the Computational Fluid-Particle Dynamics (CFPD) approach and validated through in vitro experiments. RESULTS Following the excision of the middle turbinate, a significant escalation in airflow was observed within the upper-middle region of the nasal cavities. Pollen deposition was observed to be more prominent in the nasal septum, laryngopharynx, and maxillary sinus, varying with the types of MT procedures. Notably, particles with diameters smaller than 50 μm exhibited two distinct "high peaks" and three "small peaks" within the nasal airways. CONCLUSION MT resulted in increased airflow volume within the upper-middle region of the nasal cavities. Following MT, notable shifts in pollen particle deposition hot spots were observed, transitioning from the nasal vestibule, nasal septum, and middle meatus to the nasal septum and laryngopharynx. These findings are anticipated to contribute valuable perspectives on pollen inhalation exposure risk assessments following diverse MT surgical interventions.
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Affiliation(s)
- Ruiping Ma
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710000, China
| | - Zhenzhen Hu
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710000, China
| | - Lin Tian
- School of Engineering - Mechanical and Automotive, RMIT University, Bundoora, VIC, Australia
| | - Guoxi Zheng
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710000, China
| | - Yusheng Wang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710000, China
| | - Xiaole Chen
- School of Energy and Mechanical Engineering, Nanjing Normal University, Nanjing, Jiangsu 210046, China
| | - Miao Lou
- Department of Otolaryngology Head and Neck Surgery, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710021, China
| | - Minjie Gong
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710000, China
| | - Botao Wang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710000, China
| | - Feilun Yang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710000, China
| | - Jingliang Dong
- Institute for Sustainable Industries & Liveable Cities, Victoria University, PO Box 14428, Melbourne, VIC 8001, Australia; First Year College, Victoria University, Footscray Park Campus, Footscray, VIC 3011, Australia.
| | - Ya Zhang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710000, China.
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Kim H, Choi B, Lee C, Paik JH, Jang CG, Weiss-Schneeweiss H, Jang TS. Does the evolution of micromorphology accompany chromosomal changes on dysploid and polyploid levels in the Barnardia japonica complex (Hyacinthaceae)? BMC PLANT BIOLOGY 2023; 23:485. [PMID: 37817118 PMCID: PMC10565974 DOI: 10.1186/s12870-023-04456-9] [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: 05/10/2023] [Accepted: 09/12/2023] [Indexed: 10/12/2023]
Abstract
BACKGROUND Chromosome number and genome size changes via dysploidy and polyploidy accompany plant diversification and speciation. Such changes often impact also morphological characters. An excellent system to address the questions of how extensive and structured chromosomal changes within one species complex affect the phenotype is the monocot species complex of Barnardia japonica. This taxon contains two well established and distinct diploid cytotypes differing in base chromosome numbers (AA: x = 8, BB: x = 9) and their allopolyploid derivatives on several ploidy levels (from 3x to 6x). This extensive and structured genomic variation, however, is not mirrored by gross morphological differentiation. RESULTS The current study aims to analyze the correlations between the changes of chromosome numbers and genome sizes with palynological and leaf micromorphological characters in diploids and selected allopolyploids of the B. japonica complex. The chromosome numbers varied from 2n = 16 and 18 (2n = 25 with the presence of supernumerary B chromosomes), and from 2n = 26 to 51 in polyploids on four different ploidy levels (3x, 4x, 5x, and 6x). Despite additive chromosome numbers compared to diploid parental cytotypes, all polyploid cytotypes have experienced genome downsizing. Analyses of leaf micromorphological characters did not reveal any diagnostic traits that could be specifically assigned to individual cytotypes. The variation of pollen grain sizes correlated positively with ploidy levels. CONCLUSIONS This study clearly demonstrates that karyotype and genome size differentiation does not have to be correlated with morphological differentiation of cytotypes.
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Affiliation(s)
- Hyeonjin Kim
- Department of Biological Science, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
| | - Bokyung Choi
- Department of Biological Science, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
| | - Changyoung Lee
- International Biological Material Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Jin-Hyub Paik
- International Biological Material Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Chang-Gee Jang
- Department of Biology Education, Kongju National University, Gongju, 32588, Republic of Korea
| | - Hanna Weiss-Schneeweiss
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, A-1030, Austria.
| | - Tae-Soo Jang
- Department of Biological Science, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, Republic of Korea.
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Schindfessel C, De Storme N, Trinh HK, Geelen D. Asynapsis and meiotic restitution in tomato male meiosis induced by heat stress. FRONTIERS IN PLANT SCIENCE 2023; 14:1210092. [PMID: 37521921 PMCID: PMC10373595 DOI: 10.3389/fpls.2023.1210092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 06/26/2023] [Indexed: 08/01/2023]
Abstract
Susceptibility of the reproductive system to temperature fluctuations is a recurrent problem for crop production under a changing climate. The damage is complex as multiple processes in male and female gamete formation are affected, but in general, particularly pollen production is impaired. Here, the impact of short periods of elevated temperature on male meiosis of tomato (Solanum lycopersicon L.) is reported. Meiocytes in early stage flower buds exposed to heat stress (>35°C) exhibit impaired homolog synapsis resulting in partial to complete omission of chiasmata formation. In the absence of chiasmata, univalents segregate randomly developing unbalanced tetrads and polyads resulting in aneuploid spores. However, most heat-stressed meiotic buds primarily contain balanced dyads, indicating a propensity to execute meiotic restitution. With most meiocytes exhibiting a complete loss of chiasma formation and concomitantly showing a mitotic-like division, heat stress triggers first division restitution resulting in clonal spores. These findings corroborate with the plasticity of male meiosis under heat and establish a natural route for the induction of sexual polyploidization in plants and the engineering of clonal seed.
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Affiliation(s)
- Cédric Schindfessel
- Horticell Lab, Faculty of Bioscience Engineering, Department of Plants and Crops, Ghent University, Ghent, Belgium
| | - Nico De Storme
- Horticell Lab, Faculty of Bioscience Engineering, Department of Plants and Crops, Ghent University, Ghent, Belgium
| | - Hoang Khai Trinh
- Horticell Lab, Faculty of Bioscience Engineering, Department of Plants and Crops, Ghent University, Ghent, Belgium
- Institute of Food and Biotechnology, Can Tho University, Can Tho, Vietnam
| | - Danny Geelen
- Horticell Lab, Faculty of Bioscience Engineering, Department of Plants and Crops, Ghent University, Ghent, Belgium
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Calvo‐Baltanás V, De Jaeger‐Braet J, Cher WY, Schönbeck N, Chae E, Schnittger A, Wijnker E. Knock-down of gene expression throughout meiosis and pollen formation by virus-induced gene silencing in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:19-37. [PMID: 35340073 PMCID: PMC9543169 DOI: 10.1111/tpj.15733] [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: 04/22/2021] [Revised: 02/16/2022] [Accepted: 02/18/2022] [Indexed: 06/14/2023]
Abstract
Through the inactivation of genes that act during meiosis it is possible to direct the genetic make-up of plants in subsequent generations and optimize breeding schemes. Offspring may show higher recombination of parental alleles resulting from elevated crossover (CO) incidence, or by omission of meiotic divisions, offspring may become polyploid. However, stable mutations in genes essential for recombination, or for either one of the two meiotic divisions, can have pleiotropic effects on plant morphology and line stability, for instance by causing lower fertility. Therefore, it is often favorable to temporarily change gene expression during meiosis rather than relying on stable null mutants. It was previously shown that virus-induced gene silencing (VIGS) can be used to transiently reduce CO frequencies. We asked if VIGS could also be used to modify other processes throughout meiosis and during pollen formation in Arabidopsis thaliana. Here, we show that VIGS-mediated knock-down of FIGL1, RECQ4A/B, OSD1 and QRT2 can induce (i) an increase in chiasma numbers, (ii) unreduced gametes and (iii) pollen tetrads. We further show that VIGS can target both sexes and different genetic backgrounds and can simultaneously silence different gene copies. The successful knock-down of these genes in A. thaliana suggests that VIGS can be exploited to manipulate any process during or shortly after meiosis. Hence, the transient induction of changes in inheritance patterns can be used as a powerful tool for applied research and biotechnological applications.
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Affiliation(s)
- Vanesa Calvo‐Baltanás
- Laboratory of GeneticsWageningen University & ResearchDroevendaalsesteeg 1Wageningen6700 AAthe Netherlands
- Department of Developmental Biology, Institut für Pflanzenwissenschaften und MikrobiologieUniversity of HamburgOhnhorststrasse 18Hamburg22609Germany
- Department of Biological SciencesNational University of Singapore14 Science Drive 4Singapore117543Singapore
| | - Joke De Jaeger‐Braet
- Department of Developmental Biology, Institut für Pflanzenwissenschaften und MikrobiologieUniversity of HamburgOhnhorststrasse 18Hamburg22609Germany
| | - Wei Yuan Cher
- A*STAR, Institute of Molecular and Cell Biology (IMCB)61 Biopolis DriveProteos138673Singapore
| | - Nils Schönbeck
- Department of Developmental Biology, Institut für Pflanzenwissenschaften und MikrobiologieUniversity of HamburgOhnhorststrasse 18Hamburg22609Germany
- UKEMartinistrasse 5220251HamburgGermany
| | - Eunyoung Chae
- Department of Biological SciencesNational University of Singapore14 Science Drive 4Singapore117543Singapore
| | - Arp Schnittger
- Department of Developmental Biology, Institut für Pflanzenwissenschaften und MikrobiologieUniversity of HamburgOhnhorststrasse 18Hamburg22609Germany
| | - Erik Wijnker
- Laboratory of GeneticsWageningen University & ResearchDroevendaalsesteeg 1Wageningen6700 AAthe Netherlands
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Evidence That 2n Eggs Explain Partial Hybrids between Medicago sativa and Medicago arborea. PLANTS 2022; 11:plants11101380. [PMID: 35631805 PMCID: PMC9144188 DOI: 10.3390/plants11101380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/15/2022] [Accepted: 05/18/2022] [Indexed: 12/03/2022]
Abstract
Selected genotypes of alfalfa (Medicago sativa) produce partial hybrids in sexual crosses with Medicago arborea, as reported in Plants (2013). The hybrids contain mostly alfalfa DNA and traits, but also contain DNA and traits from M. arborea. It was proposed in 2008 that the partial hybrids could be explained by fertilization of 2n eggs in alfalfa by normal pollen from M. arborea, followed by partial loss of M. arborea chromosomes during embryogenesis. In this paper, we confirm the presence of 2n eggs in the first alfalfa parents that produced hybrids. The test for 2n eggs involved pollinating 4x alfalfa with pollen from 8x alfalfa. The production of 8x progeny in the cross proved that selected alfalfa parents produced 2n eggs. Thus, 2n eggs appear to explain how the partial hybrids (hereafter hybrids) contain mostly alfalfa DNA and traits. However, two of the six alfalfa plants that did not hybridize with M. arborea also had 2n eggs. Thus, although 2n eggs explain the alfalfa content of hybrids, 2n eggs are not the only factor involved in weakening the hybridization barrier, and in transferring genes to alfalfa from M. arborea.
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Wang J, Kambhampati S, Allen DK, Chen LQ. Comparative Metabolic Analysis Reveals a Metabolic Switch in Mature, Hydrated, and Germinated Pollen in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2022; 13:836665. [PMID: 35665175 PMCID: PMC9158543 DOI: 10.3389/fpls.2022.836665] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 03/29/2022] [Indexed: 05/06/2023]
Abstract
Pollen germination is an essential process for pollen tube growth, pollination, and therefore seed production in flowering plants, and it requires energy either from remobilization of stored carbon sources, such as lipids and starches, or from secreted exudates from the stigma. Transcriptome analysis from in vitro pollen germination previously showed that 14 GO terms, including metabolism and energy, were overrepresented in Arabidopsis. However, little is understood about global changes in carbohydrate and energy-related metabolites during the transition from mature pollen grain to hydrated pollen, a prerequisite to pollen germination, in most plants, including Arabidopsis. In this study, we investigated differential metabolic pathway enrichment among mature, hydrated, and germinated pollen using an untargeted metabolomic approach. Integration of publicly available transcriptome data with metabolomic data generated as a part of this study revealed starch and sucrose metabolism increased significantly during pollen hydration and germination. We analyzed in detail alterations in central metabolism, focusing on soluble carbohydrates, non-esterified fatty acids, glycerophospholipids, and glycerolipids. We found that several metabolites, including palmitic acid, oleic acid, linolenic acid, quercetin, luteolin/kaempferol, and γ-aminobutyric acid (GABA), were elevated in hydrated pollen, suggesting a potential role in activating pollen tube emergence. The metabolite levels of mature, hydrated, and germinated pollen, presented in this work provide insights on the molecular basis of pollen germination.
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Affiliation(s)
- Jiang Wang
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | | | - Doug K. Allen
- Donald Danforth Plant Science Center, St. Louis, MO, United States
- United States Department of Agriculture, Agricultural Research Service, St. Louis, MO, United States
| | - Li-Qing Chen
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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Prochazkova K, Finke A, Tomaštíková ED, Filo J, Bente H, Dvořák P, Ovečka M, Šamaj J, Pecinka A. Zebularine induces enzymatic DNA-protein crosslinks in 45S rDNA heterochromatin of Arabidopsis nuclei. Nucleic Acids Res 2021; 50:244-258. [PMID: 34904670 PMCID: PMC8754632 DOI: 10.1093/nar/gkab1218] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/01/2021] [Indexed: 11/14/2022] Open
Abstract
Loss of genome stability leads to reduced fitness, fertility and a high mutation rate. Therefore, the genome is guarded by the pathways monitoring its integrity and neutralizing DNA lesions. To analyze the mechanism of DNA damage induction by cytidine analog zebularine, we performed a forward-directed suppressor genetic screen in the background of Arabidopsis thaliana zebularine-hypersensitive structural maintenance of chromosomes 6b (smc6b) mutant. We show that smc6b hypersensitivity was suppressed by the mutations in EQUILIBRATIVE NUCLEOSIDE TRANSPORTER 3 (ENT3), DNA METHYLTRANSFERASE 1 (MET1) and DECREASE IN DNA METHYLATION 1 (DDM1). Superior resistance of ent3 plants to zebularine indicated that ENT3 is likely necessary for the import of the drug to the cells. Identification of MET1 and DDM1 suggested that zebularine induces DNA damage by interference with the maintenance of CG DNA methylation. The same holds for structurally similar compounds 5-azacytidine and 2-deoxy-5-azacytidine. Based on our genetic and biochemical data, we propose that zebularine induces enzymatic DNA–protein crosslinks (DPCs) of MET1 and zebularine-containing DNA in Arabidopsis, which was confirmed by native chromatin immunoprecipitation experiments. Moreover, zebularine-induced DPCs accumulate preferentially in 45S rDNA chromocenters in a DDM1-dependent manner. These findings open a new avenue for studying genome stability and DPC repair in plants.
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Affiliation(s)
| | | | - Eva Dvořák Tomaštíková
- Institute of Experimental Botany, The Czech Academy of Sciences, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 31, 77900 Olomouc, Czech Republic
| | - Jaroslav Filo
- Institute of Experimental Botany, The Czech Academy of Sciences, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 31, 77900 Olomouc, Czech Republic
| | - Heinrich Bente
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Petr Dvořák
- Department of Botany, Faculty of Science, Palacký University Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Miroslav Ovečka
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Jozef Šamaj
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Ales Pecinka
- To whom correspondence should be addressed. Tel: +420 585 238 709;
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Williams JH. Consequences of whole genome duplication for 2n pollen performance. PLANT REPRODUCTION 2021; 34:321-334. [PMID: 34302535 DOI: 10.1007/s00497-021-00426-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 07/17/2021] [Indexed: 06/13/2023]
Abstract
The vegetative cell of the angiosperm male gametophyte (pollen) functions as a free-living, single-celled organism that both produces and transports sperm to egg. Whole-genome duplication (WGD) should have strong effects on pollen because of the haploid to diploid transition and because of both genetic and epigenetic effects on cell-level phenotypes. To disentangle historical effects of WGD on pollen performance, studies can compare 1n pollen from diploids to neo-2n pollen from diploids and synthetic autotetraploids to older 2n pollen from established neo-autotetraploids. WGD doubles both gene number and bulk nuclear DNA mass, and a substantial proportion of diploid and autotetraploid heterozygosity can be transmitted to 2n pollen. Relative to 1n pollen, 2n pollen can exhibit heterosis due to higher gene dosage, higher heterozygosity and new allelic interactions. Doubled genome size also has consequences for gene regulation and expression as well as epigenetic effects on cell architecture. Pollen volume doubling is a universal effect of WGD, whereas an increase in aperture number is common among taxa with simultaneous microsporogenesis and pored apertures, mostly eudicots. WGD instantly affects numerous evolved compromises among mature pollen functional traits and these are rapidly shaped by highly diverse tissue interactions and pollen competitive environments in the early post-WGD generations. 2n pollen phenotypes generally incur higher performance costs, and the degree to which these are met or evolve by scaling up provisioning and metabolic vigor needs further study.
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Affiliation(s)
- Joseph H Williams
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA.
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10
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Schindfessel C, Drozdowska Z, De Mooij L, Geelen D. Loss of obligate crossovers, defective cytokinesis and male sterility in barley caused by short-term heat stress. PLANT REPRODUCTION 2021; 34:243-253. [PMID: 34021795 DOI: 10.1007/s00497-021-00415-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 05/14/2021] [Indexed: 05/16/2023]
Abstract
Short-term heat stress during male meiosis causes defects in crossover formation, meiotic progression and cell wall formation in the monocot barley, ultimately leading to pollen abortion. High temperature conditions cause a reduction of fertility due to alterations in meiotic processes and gametogenesis. The male gametophyte development has been shown to be particularly sensitive to heat stress, and even short-term and modest temperature shifts cause alterations in crossover formation. In line with previous reports, we observed that male meiosis in the monocot barley exposed for 24-45 h to heat stress (32-42 °C) partially or completely eliminates obligate crossover formation and causes unbalanced chromosome segregation and meiotic abortion. Depending on the severity of heat stress, the structure and organization of the chromosomes were altered. In addition to alterations in chromosome structure and dynamics, heat treatment abolished or reduced the formation of a callose wall surrounding the meiocytes and interrupted the cell cycle progression leading to cytokinesis defects and microspore cell death.
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Affiliation(s)
- Cédric Schindfessel
- Department of Plants and Crops, Unit HortiCell, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Zofia Drozdowska
- Department of Plants and Crops, Unit HortiCell, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Len De Mooij
- Department of Plants and Crops, Unit HortiCell, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Danny Geelen
- Department of Plants and Crops, Unit HortiCell, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
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Alabdullah AK, Moore G, Martín AC. A Duplicated Copy of the Meiotic Gene ZIP4 Preserves up to 50% Pollen Viability and Grain Number in Polyploid Wheat. BIOLOGY 2021; 10:290. [PMID: 33918149 PMCID: PMC8065865 DOI: 10.3390/biology10040290] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 12/20/2022]
Abstract
Although most flowering plants are polyploid, little is known of how the meiotic process evolves after polyploidisation to stabilise and preserve fertility. On wheat polyploidisation, the major meiotic gene ZIP4 on chromosome 3B duplicated onto 5B and diverged (TaZIP4-B2). TaZIP4-B2 was recently shown to promote homologous pairing, synapsis and crossover, and suppress homoeologous crossover. We therefore suspected that these meiotic stabilising effects could be important for preserving wheat fertility. A CRISPR Tazip4-B2 mutant was exploited to assess the contribution of the 5B duplicated ZIP4 copy in maintaining pollen viability and grain setting. Analysis demonstrated abnormalities in 56% of meiocytes in the Tazip4-B2 mutant, with micronuclei in 50% of tetrads, reduced size in 48% of pollen grains and a near 50% reduction in grain number. Further studies showed that most of the reduced grain number occurred when Tazip4-B2 mutant plants were pollinated with the less viable Tazip4-B2 mutant pollen rather than with wild type pollen, suggesting that the stabilising effect of TaZIP4-B2 on meiosis has a greater consequence in subsequent male, rather than female gametogenesis. These studies reveal the extraordinary value of the wheat chromosome 5B TaZIP4-B2 duplication to agriculture and human nutrition. Future studies should further investigate the role of TaZIP4-B2 on female fertility and assess whether different TaZIP4-B2 alleles exhibit variable effects on meiotic stabilisation and/or resistance to temperature change.
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Affiliation(s)
| | - Graham Moore
- Crop Genetics Department, John Innes Centre, Colney, Norwich NR4 7UH, UK; (A.K.A.); (A.C.M.)
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Liu B, Jin C, De Storme N, Schotte S, Schindfessel C, De Meyer T, Geelen D. A Hypomorphic Mutant of PHD Domain Protein Male Meiocytes Death 1. Genes (Basel) 2021; 12:516. [PMID: 33916197 PMCID: PMC8066392 DOI: 10.3390/genes12040516] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 03/24/2021] [Accepted: 03/26/2021] [Indexed: 01/04/2023] Open
Abstract
Meiosis drives reciprocal genetic exchanges and produces gametes with halved chromosome number, which is important for the genetic diversity, plant viability, and ploidy consistency of flowering plants. Alterations in chromosome dynamics and/or cytokinesis during meiosis may lead to meiotic restitution and the formation of unreduced microspores. In this study, we isolated an Arabidopsis mutant male meiotic restitution 1 (mmr1), which produces a small subpopulation of diploid or polyploid pollen grains. Cytological analysis revealed that mmr1 produces dyads, triads, and monads indicative of male meiotic restitution. Both homologous chromosomes and sister chromatids in mmr1 are separated normally, but chromosome condensation at metaphase I is slightly affected. The mmr1 mutant displayed incomplete meiotic cytokinesis. Supportively, immunostaining of the microtubular cytoskeleton showed that the spindle organization at anaphase II and mini-phragmoplast formation at telophase II are aberrant. The causative mutation in mmr1 was mapped to chromosome 1 at the chromatin regulator Male Meiocyte Death 1 (MMD1/DUET) locus. mmr1 contains a C-to-T transition at the third exon of MMD1/DUET at the genomic position 2168 bp from the start codon, which causes an amino acid change G618D that locates in the conserved PHD-finger domain of histone binding proteins. The F1 progenies of mmr1 crossing with knockout mmd1/duet mutant exhibited same meiotic defects and similar meiotic restitution rate as mmr1. Taken together, we here report a hypomorphic mmd1/duet allele that typically shows defects in microtubule organization and cytokinesis.
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Affiliation(s)
- Bing Liu
- College of Life Sciences, South-Central University for Nationalities, Wuhan 430074, China
- Unit HortiCell, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium; (C.J.); (N.D.S.); (S.S.); (C.S.)
| | - Chunlian Jin
- Unit HortiCell, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium; (C.J.); (N.D.S.); (S.S.); (C.S.)
| | - Nico De Storme
- Unit HortiCell, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium; (C.J.); (N.D.S.); (S.S.); (C.S.)
- Division of Crop Biotechnics, Department of Biosystems, KU Leuven, 3001 Leuven, Belgium
| | - Sébastien Schotte
- Unit HortiCell, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium; (C.J.); (N.D.S.); (S.S.); (C.S.)
| | - Cédric Schindfessel
- Unit HortiCell, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium; (C.J.); (N.D.S.); (S.S.); (C.S.)
| | - Tim De Meyer
- Department of Data Analysis and Mathematical Modelling, Ghent University, Coupure Links, 9000 Ghent, Belgium;
| | - Danny Geelen
- Unit HortiCell, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium; (C.J.); (N.D.S.); (S.S.); (C.S.)
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Mau M, Liiving T, Fomenko L, Goertzen R, Paczesniak D, Böttner L, Sharbel TF. The spread of infectious asexuality through haploid pollen. THE NEW PHYTOLOGIST 2021; 230:804-820. [PMID: 33421128 DOI: 10.1111/nph.17174] [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: 09/30/2020] [Accepted: 12/26/2020] [Indexed: 05/16/2023]
Abstract
The mechanisms of initiation and transmission of apomixis (asexual reproduction through seeds) in natural plant populations are important for understanding the evolution of reproductive variation. Here, we used the phylogenetic diversity of the genus Boechera (Brassicaceae), together with natural diversity in pollen types produced by apomictic lines, to test whether hybridization triggers the transition to asexuality, and whether a 'triploid bridge' is required for the formation of polyploid apomicts. We performed crosses between diploid sexual recipient and diploid apomictic donor lines and tested whether the mating system (interspecific hybridization vs intraspecific outcrossing) or pollen type (haploid vs diploid) influenced the transmission of apomixis from diploid apomictic donors into sexual recipients. We used genetic markers and flow cytometric analyses of embryo and endosperm in seeds to infer the reproductive mode. Within a single generation, initiation of both diploid and polyploid apomixis in sexual Boechera can occur. Diploid apomixis is transmitted through haploid pollen (infectious asexuality) and polyploids can form through multiple pathways. The three functional elements of apomixis occasionally segregate. Variation in pollen ploidy and the segregation of apomixis elements drive reproductive diversity of hybrids and outcrosses and can be utilized for apomixis initiation in crop breeding programs.
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Affiliation(s)
- Martin Mau
- Apomixis Research Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, D-06466, Germany
- Global Institute for Food Security, University of Saskatchewan, 110 Gymnasium Place, Saskatoon, SK, S7N5C2, Canada
| | - Tiina Liiving
- Apomixis Research Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, D-06466, Germany
- Global Institute for Food Security, University of Saskatchewan, 110 Gymnasium Place, Saskatoon, SK, S7N5C2, Canada
| | - Liza Fomenko
- Global Institute for Food Security, University of Saskatchewan, 110 Gymnasium Place, Saskatoon, SK, S7N5C2, Canada
| | - Richard Goertzen
- Global Institute for Food Security, University of Saskatchewan, 110 Gymnasium Place, Saskatoon, SK, S7N5C2, Canada
| | - Dorota Paczesniak
- Apomixis Research Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, D-06466, Germany
- Global Institute for Food Security, University of Saskatchewan, 110 Gymnasium Place, Saskatoon, SK, S7N5C2, Canada
| | - Laura Böttner
- Apomixis Research Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, D-06466, Germany
| | - Timothy F Sharbel
- Apomixis Research Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, D-06466, Germany
- Global Institute for Food Security, University of Saskatchewan, 110 Gymnasium Place, Saskatoon, SK, S7N5C2, Canada
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Abstract
Polyploidization or whole genome duplication (WGD) is one of the main forces driving plant genome evolution and biodiversity with major implications for plant breeding and crop improvement. In nature, de novo formation of polyploid plant genomes most likely occurs through a modification of the sexual reproductive pathway. By interfering with reproductive genome stability, for example, via induction of meiotic restitution, diploid or polyploid gametes are ectopically formed that may participate in fertilization to yield polyploid offspring. This mechanism of WGD is generally referred to as sexual polyploidization. Considering the central role of sexual polyploidization in speciation, genome evolution and crop breeding, we provide here a set of methodologies to induce and characterize 2n pollen grain formation in plants. Using Arabidopsis thaliana as a model, we outline two different methods, that is, one chemical and one environmental, to induce male meiotic restitution and high frequency 2n pollen grain formation. In addition, we provide a set of simple and straightforward techniques to characterize alterations in male meiotic cell division and gametophytic ploidy stability underpinning 2n pollen formation. This comprehensive toolbox is applicable in a broad range of plant species to enable quick induction and assessment of 2n gamete formation during plant male reproduction.
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15
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Ascari L, Cristofori V, Macrì F, Botta R, Silvestri C, De Gregorio T, Huerta ES, Di Berardino M, Kaufmann S, Siniscalco C. Hazelnut Pollen Phenotyping Using Label-Free Impedance Flow Cytometry. FRONTIERS IN PLANT SCIENCE 2020; 11:615922. [PMID: 33370424 PMCID: PMC7753158 DOI: 10.3389/fpls.2020.615922] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 11/13/2020] [Indexed: 05/23/2023]
Abstract
Impedance flow cytometry (IFC) is a versatile lab-on-chip technology which enables fast and label-free analysis of pollen grains in various plant species, promising new research possibilities in agriculture and plant breeding. Hazelnut is a monoecious, anemophilous species, exhibiting sporophytic self-incompatibility. Its pollen is dispersed by wind in midwinter when temperatures are still low and relative humidity is usually high. Previous research found that hazelnut can be characterized by high degrees of pollen sterility following a reciprocal chromosome translocation occurring in some cultivated genotypes. In this study, IFC was used for the first time to characterize hazelnut pollen biology. IFC was validated via dye exclusion in microscopy and employed to (i) follow pollen hydration over time to define the best pre-hydration treatment for pollen viability evaluation; (ii) test hazelnut pollen viability and sterility on 33 cultivars grown in a collection field located in central Italy, and two wild hazelnuts. The accessions were also characterized by their amount and distribution of catkins in the tree canopy. Pollen sterility rate greatly varied among hazelnut accessions, with one main group of highly sterile cultivars and a second group, comprising wild genotypes and the remaining cultivars, producing good quality pollen. The results support the hypothesis of recurring reciprocal translocation events in Corylus avellana cultivars, leading to the observed gametic semi-sterility. The measured hazelnut pollen viability was also strongly influenced by pollen hydration (R adj 2 = 0.83, P ≤ 0.0001) and reached its maximum at around 6 h of pre-hydration in humid chambers. Viable and dead pollen were best discriminated at around the same time of pollen pre-hydration, suggesting that high humidity levels are required for hazelnut pollen to maintain its functionality. Altogether, our results detail the value of impedance flow cytometry for high throughput phenotyping of hazelnut pollen. Further research is required to clarify the causes of pollen sterility in hazelnut, to confirm the role of reciprocal chromosome translocations and to investigate its effects on plant productivity.
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Affiliation(s)
- Lorenzo Ascari
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Valerio Cristofori
- Department of Agriculture and Forest Sciences, University of Tuscia, Viterbo, Italy
| | - Federico Macrì
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Roberto Botta
- Department of Agricultural, Forest and Food Sciences, University of Turin, Turin, Italy
| | - Cristian Silvestri
- Department of Agriculture and Forest Sciences, University of Tuscia, Viterbo, Italy
| | | | | | | | | | - Consolata Siniscalco
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
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16
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Meeus S, Šemberová K, De Storme N, Geelen D, Vallejo-Marín M. Effect of Whole-Genome Duplication on the Evolutionary Rescue of Sterile Hybrid Monkeyflowers. PLANT COMMUNICATIONS 2020; 1:100093. [PMID: 33367262 PMCID: PMC7747968 DOI: 10.1016/j.xplc.2020.100093] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/08/2020] [Accepted: 07/01/2020] [Indexed: 05/15/2023]
Abstract
Hybridization is a creative evolutionary force, increasing genomic diversity and facilitating adaptation and even speciation. Hybrids often face significant challenges to establishment, including reduced fertility that arises from genomic incompatibilities between their parents. Whole-genome duplication in hybrids (allopolyploidy) can restore fertility, cause immediate phenotypic changes, and generate reproductive isolation. Yet the survival of polyploid lineages is uncertain, and few studies have compared the performance of recently formed allopolyploids and their parents under field conditions. Here, we use natural and synthetically produced hybrid and polyploid monkeyflowers (Mimulus spp.) to study how polyploidy contributes to the fertility, reproductive isolation, phenotype, and performance of hybrids in the field. We find that polyploidization restores fertility and that allopolyploids are reproductively isolated from their parents. The phenotype of allopolyploids displays the classic gigas effect of whole-genome duplication, in which plants have larger organs and are slower to flower. Field experiments indicate that survival of synthetic hybrids before and after polyploidization is intermediate between that of the parents, whereas natural hybrids have higher survival than all other taxa. We conclude that hybridization and polyploidy can act as sources of genomic novelty, but adaptive evolution is key in mediating the establishment of young allopolyploid lineages.
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Affiliation(s)
- Sofie Meeus
- Department of Biological and Environmental Sciences. University of Stirling, Stirling FK9 4LA, UK
| | - Kristýna Šemberová
- Department of Botany, Charles University, 128 43 Prague 2, Czech Republic
| | - Nico De Storme
- Department of Plants and Crops, Ghent University, 9000 Ghent, Belgium
| | - Danny Geelen
- Department of Plants and Crops, Ghent University, 9000 Ghent, Belgium
| | - Mario Vallejo-Marín
- Department of Biological and Environmental Sciences. University of Stirling, Stirling FK9 4LA, UK
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17
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Lei X, Ning Y, Eid Elesawi I, Yang K, Chen C, Wang C, Liu B. Heat stress interferes with chromosome segregation and cytokinesis during male meiosis in Arabidopsis thaliana. PLANT SIGNALING & BEHAVIOR 2020; 15:1746985. [PMID: 32275182 PMCID: PMC7238882 DOI: 10.1080/15592324.2020.1746985] [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] [Indexed: 05/08/2023]
Abstract
In higher plants, male meiosis is a key process of microsporogenesis and is crucial for plant fertility. Male meiosis programs are prone to be influenced by altered temperature conditions. Studies have reported that an increased temperature (28°C) within a fertile threshold can affect the frequency of meiotic recombination in Arabidopsis. However, not much has been known how male meiosis responses to an extremely high temperature beyond the fertile threshold. To understand the impact of extremely high temperature on male meiosis in Arabidopsis, we treated flowering Arabidopsis plants with 36-38°C and found that the high-temperature condition significantly reduced pollen shed and plant fertility, and led to formation of pollen grains with varied sizes. The heat stress-induced unbalanced tetrads, polyad and meiotic restitution, suggesting that male meiosis was interfered. Fluorescence in situ hybridization (FISH) assay confirmed that both homologous chromosome separation and sister chromatids cohesion were influenced. Aniline blue staining of tetrad-stage pollen mother cells (PMCs) revealed that meiotic cytokinesis was severely disrupted by the heat stress. Supportively, immunolocalization of ɑ-tubulin showed that the construction of spindle and phragmoplast at both meiosis I and II were interfered. Overall, our findings demonstrate that an extremely high-temperature stress over the fertile threshold affects both chromosome segregation and cytokinesis during male meiosis by disturbing microtubular cytoskeleton in Arabidopsis.
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Affiliation(s)
- Xiaoning Lei
- Yunnan Provincial Key Laboratory of Entomological Biopharmaceutical R&D, Dali University, Dali, China
| | - Yingjie Ning
- College of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Ibrahim Eid Elesawi
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, China
- Department of Agricultural Biochemistry, Faculty of Agriculture, Zagazig University, Zagazig, Egypt
| | - Ke Yang
- College of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Chunli Chen
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, China
| | - Chong Wang
- Shanghai Engineering Research Center of Plant Germplasm Resources, College of Life Science, Shanghai Normal University, Shanghai, China
- Chong Wang Shanghai Engineering Research Center of Plant Germplasm Resources, College of Life Science, Shanghai Normal University, Shanghai, China
| | - Bing Liu
- College of Life Sciences, South-Central University for Nationalities, Wuhan, China
- CONTACT Bing Liu College of Life Sciences, South-Central University for Nationalities, Wuhan China
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18
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Rutley N, Miller G. Large-Scale Analysis of Pollen Viability and Oxidative Level Using H 2DCFDA-Staining Coupled with Flow Cytometry. Methods Mol Biol 2020; 2160:167-179. [PMID: 32529435 DOI: 10.1007/978-1-0716-0672-8_11] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Determining pollen viability and other physiological parameters is of critical importance for evaluating the reproductive capacity of plants, both for fundamental and applied sciences. Flow cytometry is a powerful high-performance high-throughput tool for analyzing large populations of cells that has been in restricted use in plant cell research and in pollen-related studies, it has been minimized mostly for determination of DNA content. Recently, we developed a flow cytometry-based approach for robust and rapid evaluation of pollen viability that utilizes the reactive oxygen species (ROS) fluorescent reporter dye H2DCFDA (Luria et al., Plant J 98(5):942-952, 2019). This new approach revealed that pollen from Arabidopsis thaliana and Solanum lycopersicum naturally distribute into two subpopulations with different ROS levels. This method can be employed for a myriad of pollen-related studies, primarily in response to stimuli such as biotic or abiotic stress. In this chapter, we describe the protocol for H2DCFDA staining coupled with flow cytometry analysis providing specific guidelines. These guidelines are broadly applicable to many other types of cellular reporters to further develop this novel approach in the field of pollen biology.
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Affiliation(s)
- Nicholas Rutley
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Gad Miller
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
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19
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Luria G, Rutley N, Lazar I, Harper JF, Miller G. Direct analysis of pollen fitness by flow cytometry: implications for pollen response to stress. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:942-952. [PMID: 30758085 DOI: 10.1111/tpj.14286] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 02/04/2019] [Accepted: 02/07/2019] [Indexed: 05/18/2023]
Abstract
Sexual reproduction in flowering plants depends on the fitness of the male gametophyte during fertilization. Because pollen development is highly sensitive to hot and cold temperature extremes, reliable methods to evaluate pollen viability are important for research into improving reproductive heat stress (HS) tolerance. Here, we describe an approach to rapidly evaluate pollen viability using a reactive oxygen species (ROS) probe dichlorodihydrofluorescein diacetate (i.e. H2 DCFDA-staining) coupled with flow cytometry. In using flow cytometry to analyze mature pollen harvested from Arabidopsis and tomato flowers, we discovered that pollen distributed bimodally into 'low-ROS' and 'high-ROS' subpopulations. Pollen germination assays following fluorescence-activated cell sorting revealed that the high-ROS pollen germinated with a frequency that was 35-fold higher than the low-ROS pollen, supporting a model in which a significant fraction of a flower's pollen remains in a low metabolic or dormant state even after hydration. The ability to use flow cytometry to quantify ROS dynamics within a large pollen population was shown by dose-dependent alterations in DCF-fluorescence in response to oxidative stress or antioxidant treatments. HS treatments (35°C) increased ROS levels, which correlated with a ~60% reduction in pollen germination. These results demonstrate the potential of using flow cytometry-based approaches to investigate metabolic changes during stress responses in pollen.
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Affiliation(s)
- Gilad Luria
- The Mina and Everard Goodman, Faculty of Life Sciences, Bar Ilan University, Ramat Gan, 5290002, Israel
| | - Nicholas Rutley
- The Mina and Everard Goodman, Faculty of Life Sciences, Bar Ilan University, Ramat Gan, 5290002, Israel
| | - Itay Lazar
- The Mina and Everard Goodman, Faculty of Life Sciences, Bar Ilan University, Ramat Gan, 5290002, Israel
| | - Jeffery F Harper
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA
| | - Gad Miller
- The Mina and Everard Goodman, Faculty of Life Sciences, Bar Ilan University, Ramat Gan, 5290002, Israel
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20
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Changes in morphogen kinetics and pollen grain size are potential mechanisms of aberrant pollen aperture patterning in previously observed and novel mutants of Arabidopsis thaliana. PLoS Comput Biol 2019; 15:e1006800. [PMID: 30817762 PMCID: PMC6394904 DOI: 10.1371/journal.pcbi.1006800] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 01/15/2019] [Indexed: 11/21/2022] Open
Abstract
Pollen provides an excellent system to study pattern formation at the single-cell level. Pollen surface is covered by the pollen wall exine, whose deposition is excluded from certain surface areas, the apertures, which vary between the species in their numbers, positions, and morphology. What determines aperture patterns is not understood. Arabidopsis thaliana normally develops three apertures, equally spaced along the pollen equator. However, Arabidopsis mutants whose pollen has higher ploidy and larger volume develop four or more apertures. To explore possible mechanisms responsible for aperture patterning, we developed a mathematical model based on the Gierer-Meinhardt system of equations. This model was able to recapitulate aperture patterns observed in the wild-type and higher-ploidy pollen. We then used this model to further explore geometric and kinetic factors that may influence aperture patterns and found that pollen size, as well as certain kinetic parameters, like diffusion and decay of morphogens, could play a role in formation of aperture patterns. In conjunction with mathematical modeling, we also performed a forward genetic screen in Arabidopsis and discovered two mutants with aperture patterns that had not been previously observed in this species but were predicted by our model. The macaron mutant develops a single ring-like aperture, matching the unusual ring-like pattern produced by the model. The doughnut mutant forms two pore-like apertures at the poles of the pollen grain. Further tests on these novel mutants, motivated by the modeling results, suggested the existence of an area of inhibition around apertures that prevents formation of additional apertures in their vicinity. This work demonstrates the ability of the theoretical model to help focus experimental efforts and to provide fundamental insights into an important biological process. Pollen is renowned for its ability to form beautiful and complex patterns on its surface. One of the most prominent patterns on the pollen surface is formed by apertures, the regions that lack deposition of the pollen wall exine and develop at precise locations which often vary between the species. How aperture patterns are created is an intriguing and poorly understood question. We developed a mathematical model that aims to explore the mechanisms responsible for the aperture patterning in the pollen of the model plant Arabidopsis. Our model showed that size of the pollen grain could be solely responsible for the increase in aperture number observed in the pollen of some Arabidopsis mutants. Additionally, kinetic parameters, such as diffusion and decay of aperture factors, could also influence aperture number. We coupled our mathematical modeling with a forward genetic screen of a mutagenized population of Arabidopsis. This screen discovered novel mutants with aperture patterns that had been predicted by our mathematical model. Further experiments on these mutants provided additional support to the modeling predictions. These results demonstrate that mathematical modeling could be a powerful tool for understanding the mechanisms responsible for patterning of pollen grains.
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21
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Nunes GL, Oliveira RRM, Guimarães JTF, Giulietti AM, Caldeira C, Vasconcelos S, Pires E, Dias M, Watanabe M, Pereira J, Jaffé R, Bandeira CHMM, Carvalho-Filho N, da Silva EF, Rodrigues TM, dos Santos FMG, Fernandes T, Castilho A, Souza-Filho PWM, Imperatriz-Fonseca V, Siqueira JO, Alves R, Oliveira G. Quillworts from the Amazon: A multidisciplinary populational study on Isoetes serracarajensis and Isoetes cangae. PLoS One 2018; 13:e0201417. [PMID: 30089144 PMCID: PMC6082551 DOI: 10.1371/journal.pone.0201417] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 07/13/2018] [Indexed: 01/20/2023] Open
Abstract
Isoetes are ancient quillworts members of the only genus of the order Isoetales. The genus is slow evolving but is resilient, and widespread worldwide. Two recently described species occur in the Eastern Brazilian Amazon, Isoetes serracarajensis and Isoetes cangae. They are found in the ironstone grasslands known as Canga. While I. serracarajensis is present mostly in seasonal water bodies, I. cangae is known to occur in a single permanent lake at the South mountain range. In this work, we undertake an extensive morphological, physiological and genetic characterization of both species to establish species boundaries and better understand the morphological and genetic features of these two species. Our results indicate that the morphological differentiation of the species is subtle and requires a quantitative assessment of morphological elements of the megaspore for diagnosis. We did not detect differences in microspore output, but morphological peculiarities may establish a reproductive barrier. Additionally, genetic analysis using DNA barcodes and whole chloroplast genomes indicate that although the plants are genetically very similar both approaches provide diagnostic characters. There was no indication of population structuring I. serracarajensis. These results set the basis for a deeper understanding of the evolution of the Isoetes genus.
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Affiliation(s)
- Gisele Lopes Nunes
- Environmental Genomics Group, Instituto Tecnológico Vale, Belém, PA, Brazil
| | | | | | - Ana Maria Giulietti
- Biodiversity and Ecosystems Services Group, Instituto Tecnológico Vale, Belém, PA, Brazil
| | - Cecílio Caldeira
- Environmental Technology Group, Instituto Tecnológico Vale, Belém, PA, Brazil
| | | | - Eder Pires
- Environmental Genomics Group, Instituto Tecnológico Vale, Belém, PA, Brazil
| | - Mariana Dias
- Environmental Genomics Group, Instituto Tecnológico Vale, Belém, PA, Brazil
| | - Maurício Watanabe
- Biodiversity and Ecosystems Services Group, Instituto Tecnológico Vale, Belém, PA, Brazil
| | - Jovani Pereira
- Biodiversity and Ecosystems Services Group, Instituto Tecnológico Vale, Belém, PA, Brazil
| | - Rodolfo Jaffé
- Biodiversity and Ecosystems Services Group, Instituto Tecnológico Vale, Belém, PA, Brazil
| | | | | | | | | | | | - Taís Fernandes
- Environmental Studies Office, Vale, Belo Horizonte, MG, Brazil
| | | | | | | | | | - Ronnie Alves
- Environmental Genomics Group, Instituto Tecnológico Vale, Belém, PA, Brazil
| | - Guilherme Oliveira
- Environmental Genomics Group, Instituto Tecnológico Vale, Belém, PA, Brazil
- * E-mail:
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22
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The widespread and overlooked replacement of Spartina maritima by non-indigenous S. anglica and S. townsendii in north-western Adriatic saltmarshes. Biol Invasions 2018. [DOI: 10.1007/s10530-017-1654-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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23
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Tello J, Montemayor MI, Forneck A, Ibáñez J. A new image-based tool for the high throughput phenotyping of pollen viability: evaluation of inter- and intra-cultivar diversity in grapevine. PLANT METHODS 2018; 14:3. [PMID: 29339970 PMCID: PMC5759351 DOI: 10.1186/s13007-017-0267-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 12/15/2017] [Indexed: 05/12/2023]
Abstract
BACKGROUND Low pollen viability may limit grapevine yield under certain conditions, causing relevant economic losses to grape-growers. It is usually evaluated by the quantification of the number of viable and non-viable pollen grains that are present in a sample after an adequate pollen grain staining procedure. Although the manual counting of both types of grains is the simplest and most sensitive approach, it is a laborious and time-demanding process. In this regard, novel image-based approaches can assist in the objective, accurate and cost-effective phenotyping of this trait. RESULTS Here, we introduce PollenCounter, an open-source macro implemented as a customizable Fiji tool for the high-throughput phenotyping of pollen viability. This tool splits RGB images of stained pollen grains into its primary channels, retaining red and green color fractionated images (which contain information on total and only viable pollen grains, respectively) for the subsequent isolation and counting of the regions of interest (pollen grains). This framework was successfully used for the analysis of pollen viability of a high number of samples collected in a large collection of grapevine cultivars. Results revealed a great genetic variability, from cultivars having very low pollen viability (like Corinto Bianco; viability: 14.1 ± 1.3%) to others with a very low presence of sterile pollen grains (Cuelga; viability: 98.2 ± 0.5%). A wide range of variability was also observed among several clones of cv. Tempranillo Tinto (from 97.9 ± 0.9 to 60.6 ± 5.9%, in the first season). Interestingly, the evaluation of this trait in a second season revealed differential genotype-specific sensitivity to environment. CONCLUSIONS The use of PollenCounter is expected to aid in different areas, including genetics research studies, crop improvement and breeding strategies that need of fast, precise and accurate results. Considering its flexibility, it can be used not only in grapevine, but also in other species showing a differential staining of viable and non-viable pollen grains. The wide phenotypic diversity observed at a species level, together with the identification of specific cultivars and clones largely differing in this trait, pave the way of further analyses aimed to understand the physiological and genetic causes driving to male sterility in grapevine.
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Affiliation(s)
- Javier Tello
- Instituto de Ciencias de la Vid y del Vino (CSIC, Gobierno de La Rioja, Universidad de La Rioja), Carretera de Burgos km 6, Finca La Grajera, 26007 Logroño, Spain
- Division of Viticulture and Pomology, Department of Crop Sciences, University of Natural Resources and Life Sciences Vienna (BOKU), Konrad Lorenz Straße 24, 3430 Tulln, Austria
| | - María Ignacia Montemayor
- Instituto de Ciencias de la Vid y del Vino (CSIC, Gobierno de La Rioja, Universidad de La Rioja), Carretera de Burgos km 6, Finca La Grajera, 26007 Logroño, Spain
| | - Astrid Forneck
- Division of Viticulture and Pomology, Department of Crop Sciences, University of Natural Resources and Life Sciences Vienna (BOKU), Konrad Lorenz Straße 24, 3430 Tulln, Austria
| | - Javier Ibáñez
- Instituto de Ciencias de la Vid y del Vino (CSIC, Gobierno de La Rioja, Universidad de La Rioja), Carretera de Burgos km 6, Finca La Grajera, 26007 Logroño, Spain
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Mursalimov S, Zagorskaya A, Deineko E. Evaluation of DNA damage in tobacco male meiocytes involved in cytomixis using comet assay. PROTOPLASMA 2018; 255:413-417. [PMID: 28702759 DOI: 10.1007/s00709-017-1144-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 07/04/2017] [Indexed: 06/07/2023]
Abstract
Cytomixis is a process of nuclear migration between plant cells. As a rule, it is detectable in male meiocytes and gives rise to the cells with micronuclei. Examination of the integrity and functional state of migrating chromatin is of great interest, since cytomixis is assumed to change the gamete karyotype. We, for the first time, used comet assay to assess the DNA integrity in the chromatin that migrates between plant meiocytes. As was shown, the cells involved in cytomixis are viable and display no signs of DNA damage. Any comet tails are undetectable in both the main nuclei of the cells involved in cytomixis and cytomictic micronuclei. On the other hand, the cytomictic micronuclei after heat shock (positive control) form typical comet tails.
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Affiliation(s)
- Sergey Mursalimov
- Siberian Branch, Russian Academy of Sciences, Institute of Cytology and Genetics, pr. Lavrentieva 10, Novosibirsk, Russian Federation, 630090.
| | - Alla Zagorskaya
- Siberian Branch, Russian Academy of Sciences, Institute of Cytology and Genetics, pr. Lavrentieva 10, Novosibirsk, Russian Federation, 630090
| | - Elena Deineko
- Siberian Branch, Russian Academy of Sciences, Institute of Cytology and Genetics, pr. Lavrentieva 10, Novosibirsk, Russian Federation, 630090
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Evolutionary Dynamics of Unreduced Gametes. Trends Genet 2017; 33:583-593. [PMID: 28732599 DOI: 10.1016/j.tig.2017.06.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 06/23/2017] [Accepted: 06/27/2017] [Indexed: 11/20/2022]
Abstract
Unreduced gametes, which have the somatic (2n) chromosome number, are an important precursor to polyploid formation and apomixis. The product of irregularities in meiosis, 2n gametes are expected to be rare and deleterious in most natural populations, contrary to their wide taxonomic distribution and the prevalence of polyploidy. To better understand this discrepancy, we review contemporary evidence related to four aspects of 2n gamete dynamics in natural populations: (i) estimates of their frequency; (ii) their environmental and genetic determinants; (iii) adaptive and nonadaptive processes regulating their evolution; and (iv) factors regulating their union and production of polyploids in diploid populations. Aided by high-throughput methods of detection, these foci will advance our understanding of variation in 2n gametes within and among species, and their role in polyploid evolution.
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Schinkel CCF, Kirchheimer B, Dullinger S, Geelen D, De Storme N, Hörandl E. Pathways to polyploidy: indications of a female triploid bridge in the alpine species Ranunculus kuepferi (Ranunculaceae). PLANT SYSTEMATICS AND EVOLUTION = ENTWICKLUNGSGESCHICHTE UND SYSTEMATIK DER PFLANZEN 2017; 303:1093-1108. [PMID: 29081576 PMCID: PMC5640749 DOI: 10.1007/s00606-017-1435-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 06/14/2017] [Indexed: 05/05/2023]
Abstract
Polyploidy is one of the most important evolutionary processes in plants. In natural populations, polyploids usually emerge from unreduced gametes which either fuse with reduced ones, resulting in triploid offspring (triploid bridge), or with other unreduced gametes, resulting in tetraploid embryos. The frequencies of these two pathways, and male versus female gamete contributions, however, are largely unexplored. Ranunculus kuepferi occurs with diploid, triploid and autotetraploid cytotypes in the Alps, whereby diploids are mostly sexual, while tetraploids are facultative apomicts. To test for the occurrence of polyploidization events by triploid bridge, we investigated 551 plants of natural populations via flow cytometric seed screening. We assessed ploidy shifts in the embryo to reconstruct female versus male gamete contributions to polyploid embryo and/or endosperm formation. Seed formation via unreduced egg cells (BIII hybrids) occurred in all three cytotypes, while only in one case both gametes were unreduced. Polyploids further formed seeds with reduced, unfertilized egg cells (polyhaploids and aneuploids). Pollen was highly variable in diameter, but only pollen >27 μm was viable, whereby diploids produced higher proportions of well-developed pollen. Pollen size was not informative for the formation of unreduced pollen. These results suggest that a female triploid bridge via unreduced egg cells is the major pathway toward polyploidization in R. kuepferi, maybe as a consequence of constraints of endosperm development. Triploids resulting from unreduced male gametes were not observed, which explains the lack of obligate sexual tetraploid individuals and populations. Unreduced egg cell formation in diploids represents the first step toward apomixis.
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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
| | - Bernhard Kirchheimer
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Stefan Dullinger
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Danny Geelen
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Nico De Storme
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - 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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27
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Schinkel CCF, Kirchheimer B, Dullinger S, Geelen D, De Storme N, Hörandl E. Pathways to polyploidy: indications of a female triploid bridge in the alpine species Ranunculus kuepferi (Ranunculaceae). PLANT SYSTEMATICS AND EVOLUTION = ENTWICKLUNGSGESCHICHTE UND SYSTEMATIK DER PFLANZEN 2017; 303:1093-1108. [PMID: 29081576 DOI: 10.1007/s00606-017-1435-1436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 06/14/2017] [Indexed: 05/20/2023]
Abstract
Polyploidy is one of the most important evolutionary processes in plants. In natural populations, polyploids usually emerge from unreduced gametes which either fuse with reduced ones, resulting in triploid offspring (triploid bridge), or with other unreduced gametes, resulting in tetraploid embryos. The frequencies of these two pathways, and male versus female gamete contributions, however, are largely unexplored. Ranunculus kuepferi occurs with diploid, triploid and autotetraploid cytotypes in the Alps, whereby diploids are mostly sexual, while tetraploids are facultative apomicts. To test for the occurrence of polyploidization events by triploid bridge, we investigated 551 plants of natural populations via flow cytometric seed screening. We assessed ploidy shifts in the embryo to reconstruct female versus male gamete contributions to polyploid embryo and/or endosperm formation. Seed formation via unreduced egg cells (BIII hybrids) occurred in all three cytotypes, while only in one case both gametes were unreduced. Polyploids further formed seeds with reduced, unfertilized egg cells (polyhaploids and aneuploids). Pollen was highly variable in diameter, but only pollen >27 μm was viable, whereby diploids produced higher proportions of well-developed pollen. Pollen size was not informative for the formation of unreduced pollen. These results suggest that a female triploid bridge via unreduced egg cells is the major pathway toward polyploidization in R. kuepferi, maybe as a consequence of constraints of endosperm development. Triploids resulting from unreduced male gametes were not observed, which explains the lack of obligate sexual tetraploid individuals and populations. Unreduced egg cell formation in diploids represents the first step toward apomixis.
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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
| | - Bernhard Kirchheimer
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Stefan Dullinger
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Danny Geelen
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Nico De Storme
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - 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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Sora D, Kron P, Husband BC. Genetic and environmental determinants of unreduced gamete production in Brassica napus, Sinapis arvensis and their hybrids. Heredity (Edinb) 2016; 117:440-448. [PMID: 27577694 PMCID: PMC5117845 DOI: 10.1038/hdy.2016.69] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 07/08/2016] [Accepted: 07/13/2016] [Indexed: 11/08/2022] Open
Abstract
Unreduced gametes, sperm or egg cells with the somatic chromosome number, are an important mechanism of polyploid formation and gene flow between heteroploid plants. The meiotic processes leading to unreduced gamete formation are well documented, but the relative influence of environmental and genetic factors on the frequency of unreduced gametes remain largely untested. Furthermore, direct estimates of unreduced gametes based on DNA content are technically challenging and, hence, uncommon. Here, we use flow cytometry to measure the contribution of genetic (hybridization) and environmental (nutrient limitation, wounding) changes to unreduced male gamete production in Brassica napus, Sinapis arvensis and two hybrid lines. Treatments were applied to greenhouse grown plants in a random factorial design, with pollen sampled at two time intervals. Overall, the frequency of unreduced gametes averaged 0.59% (range 0.06-2.17%), plus a single outlier with 27%. Backcrossed hybrids had 39 to 75% higher unreduced gamete production than parental genotypes, averaged across all treatments, although the statistical significance of these differences depended on sampling period and wounding treatment. Unreduced gamete frequencies were higher for the second sampling period than the first. There were no direct effects of wounding or nutrient regime. Our results indicate that both genetic and environmental factors can induce increased unreduced gametes, highlighting the potential importance of environmental heterogeneity and genetic composition of populations in driving polyploid evolution.
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Affiliation(s)
- D Sora
- Department of Biology, Bioscience Complex, Queen's University, Kingston, Ontario, Canada
| | - P Kron
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - B C Husband
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
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29
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Heidmann I, Schade-Kampmann G, Lambalk J, Ottiger M, Di Berardino M. Impedance Flow Cytometry: A Novel Technique in Pollen Analysis. PLoS One 2016; 11:e0165531. [PMID: 27832091 PMCID: PMC5104384 DOI: 10.1371/journal.pone.0165531] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 10/13/2016] [Indexed: 11/29/2022] Open
Abstract
INTRODUCTION An efficient and reliable method to estimate plant cell viability, especially of pollen, is important for plant breeding research and plant production processes. Pollen quality is determined by classical methods, like staining techniques or in vitro pollen germination, each having disadvantages with respect to reliability, analysis speed, and species dependency. Analysing single cells based on their dielectric properties by impedance flow cytometry (IFC) has developed into a common method for cellular characterisation in microbiology and medicine during the last decade. The aim of this study is to demonstrate the potential of IFC in plant cell analysis with the focus on pollen. METHOD Developing and mature pollen grains were analysed during their passage through a microfluidic chip to which radio frequencies of 0.5 to 12 MHz were applied. The acquired data provided information about the developmental stage, viability, and germination capacity. The biological relevance of the acquired IFC data was confirmed by classical staining methods, inactivation controls, as well as pollen germination assays. RESULTS Different stages of developing pollen, dead, viable and germinating pollen populations could be detected and quantified by IFC. Pollen viability analysis by classical FDA staining showed a high correlation with IFC data. In parallel, pollen with active germination potential could be discriminated from the dead and the viable but non-germinating population. CONCLUSION The presented data demonstrate that IFC is an efficient, label-free, reliable and non-destructive technique to analyse pollen quality in a species-independent manner.
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Affiliation(s)
- Iris Heidmann
- Enza Zaden, Research and Development B.V. P.O. Box 7, 1600AA Enkhuizen, The Netherlands
| | | | - Joep Lambalk
- Enza Zaden, Research and Development B.V. P.O. Box 7, 1600AA Enkhuizen, The Netherlands
| | - Marcel Ottiger
- Amphasys AG, Technopark Lucerne, 6039 Root D4, Switzerland
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30
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Schinkel CCF, Kirchheimer B, Dellinger AS, Klatt S, Winkler M, Dullinger S, Hörandl E. Correlations of polyploidy and apomixis with elevation and associated environmental gradients in an alpine plant. AOB PLANTS 2016; 8:plw064. [PMID: 27594702 PMCID: PMC5091893 DOI: 10.1093/aobpla/plw064] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/29/2016] [Indexed: 05/20/2023]
Abstract
Apomictic plants expand their geographical distributions more to higher elevations compared to their sexual progenitors. It was so far unclear whether this tendency is related to mode of reproduction itself or represents a side effect of polyploidy. Apomixis is advantageous for range expansions as no mating partners and pollinators are needed (Baker's rule). Polyploidy is thought to infer fitness advantages and a higher vigour that would enable plants to adjust better to more extreme climatic conditions. However, little is known about actual performance of plants at higher elevations. We analyzed 81 populations of Ranunculus kuepferi from the whole distribution area in the European Alps to quantify apomictic versus sexual seed formation via flow cytometric seed screening. Seed set and vegetative growth were measured as fitness parameters. All parameters were correlated to geographical distribution, elevation, temperature and precipitation. Flow cytometric seed screening revealed predominantly obligate sexuality (88.9 %) and facultative apomixis in diploid populations, while tetraploid populations are predominantly facultative (65.4 %) to obligate apomictic. Apomictic seed formation correlated significantly to higher elevations, which explains also the observed niche shift to lower temperatures. However, within the tetraploid range, there is no apparent correlation of degree of facultative apomixis to geographical distance. Apomixis appeared in diploids three times independently in separated, otherwise sexual populations in the southwestern refugial areas of the Alps. Diploid apomixis was not successful in range expansions, and obligate sexual polyploids were not observed. Polyploidy may relate to cold tolerance as an adaptation to conditions at high elevations, where diploid sexuals have no fitness advantage. Instead, facultative apomixis may have aided colonization of higher elevations and range expansions in the Alps without mate and pollinator limitation, but did not necessarily involve long-distance dispersal. A direct influence of low temperatures on unreduced gamete formation cannot be ruled out.
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Affiliation(s)
- Christoph C F Schinkel
- Department of Systematics, Biodiversity and Evolution of Plants (with herbarium), Georg-August-University of Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany
| | - Bernhard Kirchheimer
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Agnes S Dellinger
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Simone Klatt
- Department of Systematics, Biodiversity and Evolution of Plants (with herbarium), Georg-August-University of Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany
| | - Manuela Winkler
- GLORIA co-ordination, University of Natural Resources and Life Sciences Vienna, Centre for Global Change and Sustainability, Vienna, Austria
| | - Stefan Dullinger
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with herbarium), Georg-August-University of Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany
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A Ploidy-Sensitive Mechanism Regulates Aperture Formation on the Arabidopsis Pollen Surface and Guides Localization of the Aperture Factor INP1. PLoS Genet 2016; 12:e1006060. [PMID: 27177036 PMCID: PMC4866766 DOI: 10.1371/journal.pgen.1006060] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 04/26/2016] [Indexed: 11/18/2022] Open
Abstract
Pollen presents a powerful model for studying mechanisms of precise formation and deposition of extracellular structures. Deposition of the pollen wall exine leads to the generation of species-specific patterns on pollen surface. In most species, exine does not develop uniformly across the pollen surface, resulting in the formation of apertures-openings in the exine that are species-specific in number, morphology and location. A long time ago, it was proposed that number and positions of apertures might be determined by the geometry of tetrads of microspores-the precursors of pollen grains arising via meiotic cytokinesis, and by the number of last-contact points between sister microspores. We have tested this model by characterizing Arabidopsis mutants with ectopic apertures and/or abnormal geometry of meiotic products. Here we demonstrate that contact points per se do not act as aperture number determinants and that a correct geometric conformation of a tetrad is neither necessary nor sufficient to generate a correct number of apertures. A mechanism sensitive to pollen ploidy, however, is very important for aperture number and positions and for guiding the aperture factor INP1 to future aperture sites. In the mutants with ectopic apertures, the number and positions of INP1 localization sites change depending on ploidy or ploidy-related cell size and not on INP1 levels, suggesting that sites for aperture formation are specified before INP1 is brought to them.
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Wang L, Haccou P, Lu BR. High-Resolution Gene Flow Model for Assessing Environmental Impacts of Transgene Escape Based on Biological Parameters and Wind Speed. PLoS One 2016; 11:e0149563. [PMID: 26959240 PMCID: PMC4784949 DOI: 10.1371/journal.pone.0149563] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 02/01/2016] [Indexed: 11/25/2022] Open
Abstract
Environmental impacts caused by transgene flow from genetically engineered (GE) crops to their wild relatives mediated by pollination are longstanding biosafety concerns worldwide. Mathematical modeling provides a useful tool for estimating frequencies of pollen-mediated gene flow (PMGF) that are critical for assessing such environmental impacts. However, most PMGF models are impractical for this purpose because their parameterization requires actual data from field experiments. In addition, most of these models are usually too general and ignored the important biological characteristics of concerned plant species; and therefore cannot provide accurate prediction for PMGF frequencies. It is necessary to develop more accurate PMGF models based on biological and climatic parameters that can be easily measured in situ. Here, we present a quasi-mechanistic PMGF model that only requires the input of biological and wind speed parameters without actual data from field experiments. Validation of the quasi-mechanistic model based on five sets of published data from field experiments showed significant correlations between the model-simulated and field experimental-generated PMGF frequencies. These results suggest accurate prediction for PMGF frequencies using this model, provided that the necessary biological parameters and wind speed data are available. This model can largely facilitate the assessment and management of environmental impacts caused by transgene flow, such as determining transgene flow frequencies at a particular spatial distance, and establishing spatial isolation between a GE crop and its coexisting non-GE counterparts and wild relatives.
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Affiliation(s)
- Lei Wang
- Ministry of Education Key Laboratory for Biodiversity and Ecological Engineering, Department of Ecology and Evolutionary Biology, Fudan University, Handan Road 220, Shanghai 200433, China
| | - Patsy Haccou
- Leiden University College The Hague, P.O. Box 13228, 2501 EE The Hague, the Netherlands
| | - Bao-Rong Lu
- Ministry of Education Key Laboratory for Biodiversity and Ecological Engineering, Department of Ecology and Evolutionary Biology, Fudan University, Handan Road 220, Shanghai 200433, China
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Mason AS, Rousseau-Gueutin M, Morice J, Bayer PE, Besharat N, Cousin A, Pradhan A, Parkin IAP, Chèvre AM, Batley J, Nelson MN. Centromere Locations in Brassica A and C Genomes Revealed Through Half-Tetrad Analysis. Genetics 2016; 202:513-23. [PMID: 26614742 PMCID: PMC4788232 DOI: 10.1534/genetics.115.183210] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/23/2015] [Indexed: 11/18/2022] Open
Abstract
Locating centromeres on genome sequences can be challenging. The high density of repetitive elements in these regions makes sequence assembly problematic, especially when using short-read sequencing technologies. It can also be difficult to distinguish between active and recently extinct centromeres through sequence analysis. An effective solution is to identify genetically active centromeres (functional in meiosis) by half-tetrad analysis. This genetic approach involves detecting heterozygosity along chromosomes in segregating populations derived from gametes (half-tetrads). Unreduced gametes produced by first division restitution mechanisms comprise complete sets of nonsister chromatids. Along these chromatids, heterozygosity is maximal at the centromeres, and homologous recombination events result in homozygosity toward the telomeres. We genotyped populations of half-tetrad-derived individuals (from Brassica interspecific hybrids) using a high-density array of physically anchored SNP markers (Illumina Brassica 60K Infinium array). Mapping the distribution of heterozygosity in these half-tetrad individuals allowed the genetic mapping of all 19 centromeres of the Brassica A and C genomes to the reference Brassica napus genome. Gene and transposable element density across the B. napus genome were also assessed and corresponded well to previously reported genetic map positions. Known centromere-specific sequences were located in the reference genome, but mostly matched unanchored sequences, suggesting that the core centromeric regions may not yet be assembled into the pseudochromosomes of the reference genome. The increasing availability of genetic markers physically anchored to reference genomes greatly simplifies the genetic and physical mapping of centromeres using half-tetrad analysis. We discuss possible applications of this approach, including in species where half-tetrads are currently difficult to isolate.
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Affiliation(s)
- Annaliese S Mason
- Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, 35392 Giessen, Germany School of Agriculture and Food Sciences and Centre for Integrative Legume Research, The University of Queensland, Brisbane 4072, Australia
| | | | - Jérôme Morice
- IGEPP, Institut National de la Recherche Agronomique, BP35327, 35653 Le Rheu, France
| | - Philipp E Bayer
- School of Agriculture and Food Sciences and Centre for Integrative Legume Research, The University of Queensland, Brisbane 4072, Australia School of Plant Biology and The University of Western Australia (UWA) Institute of Agriculture, The UWA, Crawley 6009, Perth, Australia
| | - Naghmeh Besharat
- School of Plant Biology and The University of Western Australia (UWA) Institute of Agriculture, The UWA, Crawley 6009, Perth, Australia
| | - Anouska Cousin
- School of Plant Biology and The University of Western Australia (UWA) Institute of Agriculture, The UWA, Crawley 6009, Perth, Australia
| | - Aneeta Pradhan
- School of Plant Biology and The University of Western Australia (UWA) Institute of Agriculture, The UWA, Crawley 6009, Perth, Australia
| | - Isobel A P Parkin
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan, Canada
| | - Anne-Marie Chèvre
- IGEPP, Institut National de la Recherche Agronomique, BP35327, 35653 Le Rheu, France
| | - Jacqueline Batley
- School of Plant Biology and The University of Western Australia (UWA) Institute of Agriculture, The UWA, Crawley 6009, Perth, Australia School of Agriculture and Food Sciences and Centre for Integrative Legume Research, The University of Queensland, Brisbane 4072, Australia
| | - Matthew N Nelson
- School of Plant Biology and The University of Western Australia (UWA) Institute of Agriculture, The UWA, Crawley 6009, Perth, Australia Natural Capital and Plant Health, Royal Botanic Gardens Kew, Ardingly, West Sussex, RH17 6TN, United Kingdom
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34
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Kron P, Husband BC. Distinguishing 2N gamete nuclei from doublets in pollen using flow cytometry and pulse analysis. Cytometry A 2015; 87:943-57. [DOI: 10.1002/cyto.a.22696] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 04/06/2015] [Accepted: 05/04/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Paul Kron
- Department of Integrative Biology; University of Guelph; Ontario N1G 2W1 Canada
| | - Brian C. Husband
- Department of Integrative Biology; University of Guelph; Ontario N1G 2W1 Canada
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Marinho RC, Mendes-Rodrigues C, Bonetti AM, Oliveira PE. Pollen and stomata morphometrics and polyploidy in Eriotheca (Malvaceae-Bombacoideae). PLANT BIOLOGY (STUTTGART, GERMANY) 2014; 16:508-11. [PMID: 24341784 DOI: 10.1111/plb.12135] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 10/20/2013] [Indexed: 05/13/2023]
Abstract
Approximately 70% of the angiosperm species are polyploid, an important phenomenon in the evolution of those plants. But ploidy estimates have often been hindered because of the small size and large number of chromosomes in many tropical groups. Since polyploidy affects cell size, morphometric analyses of pollen grains and stomata have been used to infer ploidy level. Polyploidy is present in many species of the Cerrado, the Neotropical savanna region in Central Brazil, and has been linked to apomixis in some taxa. Eriotheca gracilipes and Eriotheca pubescens are common tree species in this region, and present cytotypes that form reproductive mosaics. Hexaploid individuals (2n = 6x = 276) are polyembryonic and apomictic, while tetraploid and diploid individuals (2n = 2x = 92, 2n = 4x = 184) are sexual and monoembryonic. We tested whether morphometric analysis can be used to estimate ploidy levels in E. gracilipes and E. pubescens individuals. Pollen material from diploid and hexaploid individuals of E. gracilipes, and tetraploid and hexaploid individuals of E. pubescens, were fixed in 50% FAA, and expanded leaves were dried in silica gel. Pollen grains and stomata of at least five individuals from each population were measured. The results demonstrate that all measures were significantly different among cytotypes. Individuals with higher levels of ploidy (hexaploid) all presented measurements that were higher than those with lower levels (diploid and tetraploid). There was no overlap between ploidy levels in each species at 95% confidence interval. Thus, the size of the pollen grains and stomata are effective parameters for analysis of ploidy levels in E. gracilipes and E. pubescens.
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Affiliation(s)
- R C Marinho
- Programa de Pós-graduação em Genética e Bioquímica, INGEB, Universidade Federal de Uberlândia, Uberlândia, Brazil
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Kürschner WM, Batenburg SJ, Mander L. Aberrant Classopollis pollen reveals evidence for unreduced (2n) pollen in the conifer family Cheirolepidiaceae during the Triassic-Jurassic transition. Proc Biol Sci 2013; 280:20131708. [PMID: 23926159 PMCID: PMC3757988 DOI: 10.1098/rspb.2013.1708] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 07/15/2013] [Indexed: 11/12/2022] Open
Abstract
Polyploidy (or whole-genome doubling) is a key mechanism for plant speciation leading to new evolutionary lineages. Several lines of evidence show that most species among flowering plants had polyploidy ancestry, but it is virtually unknown for conifers. Here, we study variability in pollen tetrad morphology and the size of the conifer pollen type Classopollis extracted from sediments of the Triassic-Jurassic transition, 200 Ma. Classopollis producing Cheirolepidiaceae were one of the most dominant and diverse groups of conifers during the Mesozoic. We show that aberrant pollen Classopollis tetrads, triads and dyads, and the large variation in pollen size indicates the presence of unreduced (2n) pollen, which is one of the main mechanisms in modern polyploid formation. Polyploid speciation may explain the high variability of growth forms and adaptation of these conifers to different environments and their resistance to extreme growth conditions. We suggest that polyploidy may have also reduced the extinction risk of these conifers during the End-Triassic biotic crisis.
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Affiliation(s)
- Wolfram M Kürschner
- Department of Geosciences and Centre for Earth Evolution and Dynamics, University of Oslo, PO Box 1047, 0316 Oslo, Norway.
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