101
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Vallejo-Marín M, Cooley AM, Lee MY, Folmer M, McKain MR, Puzey JR. Strongly asymmetric hybridization barriers shape the origin of a new polyploid species and its hybrid ancestor. AMERICAN JOURNAL OF BOTANY 2016; 103:1272-88. [PMID: 27221281 DOI: 10.3732/ajb.1500471] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/16/2016] [Indexed: 05/11/2023]
Abstract
PREMISE OF THE STUDY Hybridization between diploids and tetraploids can lead to new allopolyploid species, often via a triploid intermediate. Viable triploids are often produced asymmetrically, with greater success observed for "maternal-excess" crosses where the mother has a higher ploidy than the father. Here we investigated the evolutionary origins of Mimulus peregrinus, an allohexaploid recently derived from the triploid M. ×robertsii, to determine whether reproductive asymmetry has shaped the formation of this new species. METHODS We used reciprocal crosses between the diploid (M. guttatus) and tetraploid (M. luteus) progenitors to determine the viability of triploid M. ×robertsii hybrids resulting from paternal- vs. maternal-excess crosses. To investigate whether experimental results predict patterns seen in the field, we performed parentage analyses comparing natural populations of M. peregrinus to its diploid, tetraploid, and triploid progenitors. Organellar sequences obtained from pre-existing genomic data, supplemented with additional genotyping was used to establish the maternal ancestry of multiple M. peregrinus and M. ×robertsii populations. KEY RESULTS We found strong evidence for asymmetric origins of M. peregrinus, but opposite to the common pattern, with paternal-excess crosses significantly more successful than maternal-excess crosses. These results successfully predicted hybrid formation in nature: 111 of 114 M. ×robertsii individuals, and 27 of 27 M. peregrinus, had an M. guttatus maternal haplotype. CONCLUSION This study, which includes the first Mimulus chloroplast genome assembly, demonstrates the utility of parentage analysis through genome skimming. We highlight the benefits of complementing genomic analyses with experimental approaches to understand asymmetry in allopolyploid speciation.
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Affiliation(s)
- Mario Vallejo-Marín
- Biological and Environmental Science, School of Natural Sciences, University of Stirling, Stirling, Scotland, FK9 4LA UK
| | - Arielle M Cooley
- Biology Department, Whitman College, Walla Walla, Washington 99362 USA
| | - Michelle Yuequi Lee
- Biological and Environmental Science, School of Natural Sciences, University of Stirling, Stirling, Scotland, FK9 4LA UK
| | - Madison Folmer
- Department of Biology, College of William and Mary, Williamsburg, Virginia 23185 USA
| | - Michael R McKain
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132 USA
| | - Joshua R Puzey
- Department of Biology, College of William and Mary, Williamsburg, Virginia 23185 USA
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102
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Barker MS, Husband BC, Pires JC. Spreading Winge and flying high: The evolutionary importance of polyploidy after a century of study. AMERICAN JOURNAL OF BOTANY 2016; 103:1139-45. [PMID: 27480249 DOI: 10.3732/ajb.1600272] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 07/20/2016] [Indexed: 05/10/2023]
Affiliation(s)
- Michael S Barker
- Department of Ecology & Evolutionary Biology, University of Arizona, Tucson, Arizona 85721 USA
| | - Brian C Husband
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1 Canada
| | - J Chris Pires
- Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211 USA
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103
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Garner AG, Kenney AM, Fishman L, Sweigart AL. Genetic loci with parent-of-origin effects cause hybrid seed lethality in crosses between Mimulus species. THE NEW PHYTOLOGIST 2016; 211:319-31. [PMID: 26924810 DOI: 10.1111/nph.13897] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 12/23/2015] [Indexed: 05/09/2023]
Abstract
In flowering plants, F1 hybrid seed lethality is a common outcome of crosses between closely related diploid species, but the genetic basis of this early-acting and potentially widespread form of postzygotic reproductive isolation is largely unknown. We intercrossed two closely related species of monkeyflower, Mimulus guttatus and Mimulus tilingii, to characterize the mechanisms and strength of postzygotic reproductive isolation. Then, using a reciprocal backcross design, we performed high-resolution genetic mapping to determine the genetic architecture of hybrid seed lethality and directly test for loci with parent-of-origin effects. We found that F1 hybrid seed lethality is an exceptionally strong isolating barrier between Mimulus species, with reciprocal crosses producing < 1% viable seeds. This form of postzygotic reproductive isolation appears to be highly polygenic, indicating that multiple incompatibility loci have accumulated rapidly between these closely related Mimulus species. It is also primarily caused by genetic loci with parent-of-origin effects, suggesting a possible role for imprinted genes in the evolution of Mimulus hybrid seed lethality. Our findings suggest that divergence in loci with parent-of-origin effects, which is probably driven by genomic coevolution within lineages, might be an important source of hybrid incompatibilities between flowering plant species.
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Affiliation(s)
- Austin G Garner
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
| | - Amanda M Kenney
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
- Department of Biological Sciences, St Edwards University, Austin, TX, 78704, USA
| | - Lila Fishman
- Department of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Andrea L Sweigart
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
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104
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Oneal E, Willis JH, Franks RG. Disruption of endosperm development is a major cause of hybrid seed inviability between Mimulus guttatus and Mimulus nudatus. THE NEW PHYTOLOGIST 2016; 210:1107-20. [PMID: 26824345 PMCID: PMC4833662 DOI: 10.1111/nph.13842] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 11/30/2015] [Indexed: 05/06/2023]
Abstract
Divergence of developmental mechanisms within populations could lead to hybrid developmental failure, and might be a factor driving speciation in angiosperms. We investigate patterns of endosperm and embryo development in Mimulus guttatus and the closely related, serpentine endemic Mimulus nudatus, and compare them to those of reciprocal hybrid seed. We address whether disruption in hybrid seed development is the primary source of reproductive isolation between these sympatric taxa. M. guttatus and M. nudatus differ in the pattern and timing of endosperm and embryo development. Some hybrid seeds exhibit early disruption of endosperm development and are completely inviable, while others develop relatively normally at first, but later exhibit impaired endosperm proliferation and low germination success. These developmental patterns are reflected in mature hybrid seeds, which are either small and flat (indicating little to no endosperm) or shriveled (indicating reduced endosperm volume). Hybrid seed inviability forms a potent reproductive barrier between M. guttatus and M. nudatus. We shed light on the extent of developmental variation between closely related species within the M. guttatus species complex, an important ecological model system, and provide a partial mechanism for the hybrid barrier between M. guttatus and M. nudatus.
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Affiliation(s)
- Elen Oneal
- Department of Biology, Duke University, 3319 French Family Science Center, 125 Science Drive, Durham, NC 27705, USA
| | - John H. Willis
- Department of Biology, Duke University, 3319 French Family Science Center, 125 Science Drive, Durham, NC 27705, USA
| | - Robert G. Franks
- Department of Genetics, North Carolina State University, 2548 Thomas Hall, Raleigh, NC 27695, USA
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105
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Durka W, Michalski SG, Berendzen KW, Bossdorf O, Bucharova A, Hermann JM, Hölzel N, Kollmann J. Genetic differentiation within multiple common grassland plants supports seed transfer zones for ecological restoration. J Appl Ecol 2016. [DOI: 10.1111/1365-2664.12636] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Walter Durka
- Department of Community Ecology (BZF); Helmholtz Centre for Environmental Research - UFZ; Theodor-Lieser-Str. 4 06120 Halle Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig; Deutscher Platz 5e 04103 Leipzig Germany
| | - Stefan G. Michalski
- Department of Community Ecology (BZF); Helmholtz Centre for Environmental Research - UFZ; Theodor-Lieser-Str. 4 06120 Halle Germany
| | - Kenneth W. Berendzen
- ZMBP - Central Facilities; University of Tübingen; Auf der Morgenstelle 32 72076 Tübingen Germany
| | - Oliver Bossdorf
- Plant Evolutionary Ecology; Institute of Evolution & Ecology; University of Tübingen; Auf der Morgenstelle 5 72076 Tübingen Germany
| | - Anna Bucharova
- Plant Evolutionary Ecology; Institute of Evolution & Ecology; University of Tübingen; Auf der Morgenstelle 5 72076 Tübingen Germany
| | - Julia-Maria Hermann
- Restoration Ecology; Department of Ecology & Ecosystem Management; Technical University Munich; Emil-Ramann-Str. 6 85354 Freising Germany
| | - Norbert Hölzel
- Biodiversity and Ecosystem Research Group; Institute of Landscape Ecology; University of Münster; Heisenbergstr. 2 48149 Münster Germany
| | - Johannes Kollmann
- Restoration Ecology; Department of Ecology & Ecosystem Management; Technical University Munich; Emil-Ramann-Str. 6 85354 Freising Germany
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106
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Wu Y, Sun Y, Wang X, Lin X, Sun S, Shen K, Wang J, Jiang T, Zhong S, Xu C, Liu B. Transcriptome shock in an interspecific F1 triploid hybrid of Oryza revealed by RNA sequencing. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2016; 58:150-164. [PMID: 25828709 DOI: 10.1111/jipb.12357] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Accepted: 03/30/2015] [Indexed: 06/04/2023]
Abstract
Interspecific hybridization is a driving force in evolution and speciation of higher plants. Interspecific hybridization often induces immediate and saltational changes in gene expression, a phenomenon collectively termed "transcriptome shock". Although transcriptome shock has been reported in various plant and animal taxa, the extent and pattern of shock-induced expression changes are often highly idiosyncratic, and hence entails additional investigations. Here, we produced a set of interspecific F1 triploid hybrid plants between Oryza sativa, ssp. japonica (2n = 2x = 24, genome AA) and the tetraploid form of O. punctata (2n = 4x = 48, genome, BBCC), and conducted RNA-seq transcriptome profiling of the hybrids and their exact parental plants. We analyzed both homeolog expression bias and overall gene expression level difference in the hybrids relative to the in silico "hybrids" (parental mixtures). We found that approximately 16% (2,541) of the 16,112 expressed genes in leaf tissue of the F1 hybrids showed nonadditive expression, which were specifically enriched in photosynthesis-related pathways. Interestingly, changes in the maternal homeolog expression, including non-stochastic silencing, were the major causes for altered homeolog expression partitioning in the F1 hybrids. Our findings have provided further insights into the transcriptome response to interspecific hybridization and heterosis.
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Affiliation(s)
- Ying Wu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Yue Sun
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Xutong Wang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Xiuyun Lin
- Jilin Academy of Agricultural Sciences, Changchun, 130032, China
| | - Shuai Sun
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Kun Shen
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Jie Wang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Tingting Jiang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Silin Zhong
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Chunming Xu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Bao Liu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
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107
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Zhou X, Mo X, Gui M, Wu X, Jiang Y, Ma L, Shi Z, Luo Y, Tang W. Cytological, molecular mechanisms and temperature stress regulating production of diploid male gametes in Dianthus caryophyllus L. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2015; 97:255-63. [PMID: 26492133 DOI: 10.1016/j.plaphy.2015.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/04/2015] [Accepted: 10/04/2015] [Indexed: 05/02/2023]
Abstract
In plant evolution, because of its key role in sexual polyploidization or whole genome duplication events, diploid gamete formation is considered as an important component in diversification and speciation. Environmental stress often triggers unreduced gamete production. However, the molecular, cellular mechanisms and adverse temperature regulating diplogamete production in carnation remain poorly understood. Here, we investigate the cytological basis for 2n male gamete formation and describe the isolation and characterization of the first gene, DcPS1 (Dianthus Caryophyllus Parallel Spindle 1). In addition, we analyze influence of temperature stress on diploid gamete formation and transcript levels of DcPS1. Cytological evidence indicated that 2n male gamete formation is attributable to abnormal spindle orientation at male meiosis II. DcPS1 protein is conserved throughout the plant kingdom and carries domains suggestive of a regulatory function. DcPS1 expression analysis show DcPS1 gene probably have a role in 2n pollen formation. Unreduced pollen formation in various cultivation was sensitive to high or low temperature which was probably regulated by the level of DcPS1 transcripts. In a broader perspective, these findings can have potential applications in fundamental polyploidization research and plant breeding programs.
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MESH Headings
- Chromosomes, Plant/genetics
- Cloning, Molecular
- Dianthus/cytology
- Dianthus/genetics
- Diploidy
- Flowers/genetics
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Plant
- Genes, Plant
- Germ Cells, Plant/cytology
- Germ Cells, Plant/metabolism
- Organ Specificity/genetics
- Phylogeny
- Pollen/cytology
- Pollen/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Stress, Physiological/genetics
- Temperature
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Affiliation(s)
- Xuhong Zhou
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Chenggong, Kunming 650500, China; Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Chenggong, Kunming 650500, China; Flower Research Institute, Yunnan Academy of Agricultural Science, Kunming 650205, China; National Engineering Research Center for Ornamental Horticulture, Kunming 650205, China
| | - Xijun Mo
- Flower Research Institute, Yunnan Academy of Agricultural Science, Kunming 650205, China; National Engineering Research Center for Ornamental Horticulture, Kunming 650205, China
| | - Min Gui
- Flower Research Institute, Yunnan Academy of Agricultural Science, Kunming 650205, China; National Engineering Research Center for Ornamental Horticulture, Kunming 650205, China
| | - Xuewei Wu
- Flower Research Institute, Yunnan Academy of Agricultural Science, Kunming 650205, China; National Engineering Research Center for Ornamental Horticulture, Kunming 650205, China
| | - Yalian Jiang
- Flower Research Institute, Yunnan Academy of Agricultural Science, Kunming 650205, China; National Engineering Research Center for Ornamental Horticulture, Kunming 650205, China
| | - Lulin Ma
- Flower Research Institute, Yunnan Academy of Agricultural Science, Kunming 650205, China; National Engineering Research Center for Ornamental Horticulture, Kunming 650205, China
| | - Ziming Shi
- Flower Research Institute, Yunnan Academy of Agricultural Science, Kunming 650205, China; National Engineering Research Center for Ornamental Horticulture, Kunming 650205, China
| | - Ying Luo
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Chenggong, Kunming 650500, China; Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Chenggong, Kunming 650500, China.
| | - Wenru Tang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Chenggong, Kunming 650500, China; Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Chenggong, Kunming 650500, China.
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108
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Zozomová-Lihová J, Malánová-Krásná I, Vít P, Urfus T, Senko D, Svitok M, Kempa M, Marhold K. Cytotype distribution patterns, ecological differentiation, and genetic structure in a diploid-tetraploid contact zone of Cardamine amara. AMERICAN JOURNAL OF BOTANY 2015; 102:1380-95. [PMID: 26290560 DOI: 10.3732/ajb.1500052] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 07/16/2015] [Indexed: 05/20/2023]
Abstract
UNLABELLED • PREMISE OF THE STUDY Contact zones between diploids and their autopolyploid descendants represent a unique evolutionary venue for studying polyploid establishment, cytotype coexistence, and interactions. Here, we examine cytotype coexistence in a diploid-tetraploid contact zone of a perennial herb, Cardamine amara, located north of the Alps by assessing cytotype spatial patterns, ecological divergence, and genetic variation and structure.• METHODS Flow cytometry was applied to screen DNA ploidy levels in 302 populations (3296 individuals) and the genetic variation of a selection of 25 populations was examined using microsatellite and AFLP markers. Environmental (landscape and climatic) data were analyzed to assess ecological differentiation between the cytotypes.• KEY RESULTS A parapatric distribution of the cytotypes with a relatively wide (over 100 km in some regions) secondary contact zone was identified. Mixed-ploidy populations, documented for the first time in this species, as well as triploid individuals were found along the diploid-tetraploid borderline. Different climatic requirements of the two main cytotypes were revealed, mirrored in their altitudinal separation. The tetraploids were genetically differentiated from both the diploids and the modeled, in silico autotetraploid genotypes, in accordance with the assumed polyploid origin and spread linked to past glaciations, and largely independent evolution in allopatry.• CONCLUSIONS The observed spatial and genetic patterns likely reflect the evolutionary and colonization history of the two cytotypes and have been maintained by multiple factors such as ecological divergence, limited gene flow between the cytotypes, and the restricted dispersal capacity.
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Affiliation(s)
- Judita Zozomová-Lihová
- Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23 Bratislava, Slovak Republic
| | | | - Petr Vít
- Department of Botany, Faculty of Sciences, Charles University, Benátská 2, CZ-128 01 Praha, Czech Republic Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
| | - Tomáš Urfus
- Department of Botany, Faculty of Sciences, Charles University, Benátská 2, CZ-128 01 Praha, Czech Republic Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
| | - Dušan Senko
- Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23 Bratislava, Slovak Republic
| | - Marek Svitok
- Faculty of Ecology and Environmental Sciences, Technical University in Zvolen, T. G. Masaryka 24, SK-960 53 Zvolen, Slovak Republic Eawag Swiss Federal Institute of Aquatic Science and Technology, Department of Aquatic Ecology, Centre of Ecology, Evolution and Biogeochemistry, Seestrasse 79, CH-6047 Kastanienbaum, Switzerland
| | - Matúš Kempa
- Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23 Bratislava, Slovak Republic
| | - Karol Marhold
- Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23 Bratislava, Slovak Republic Department of Botany, Faculty of Sciences, Charles University, Benátská 2, CZ-128 01 Praha, Czech Republic
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109
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Abstract
Understanding how seed size is regulated in angiosperms is a key goal for plant science as seed size is an important component of overall seed yield. Angiosperm seeds comprise three clearly defined components, i.e. the embryo, endosperm and seed coat, with each having a distinct genetic composition which exerts different influences on seed development. Complex cross-talk and integration of signals from these different regions of the seed together determine its final size. The present review considers some of the major regulators of seed size, with a particular emphasis on the role of the seed coat in modulating endosperm proliferation and cellularization. The innermost layer of the seed coat, the endothelium, synthesizes flavonoids which are held to provide a defensive function against microbes, act as feeding deterrents, provide UV protection and to have a role in seed dormancy. A growing body of data suggests that flavonoids may also play a fundamental role in regulating communication between the seed coat and the endosperm. In the present review, we discuss how this may be achieved in the light of the fact that several flavonoids are known to be potent auxin transport regulators.
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110
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Song Q, Chen ZJ. Epigenetic and developmental regulation in plant polyploids. CURRENT OPINION IN PLANT BIOLOGY 2015; 24:101-9. [PMID: 25765928 PMCID: PMC4395545 DOI: 10.1016/j.pbi.2015.02.007] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 02/18/2015] [Accepted: 02/18/2015] [Indexed: 05/18/2023]
Abstract
Polyploidy or whole-genome duplication occurs in some animals and many flowering plants, including many important crops such as wheat, cotton and oilseed rape. The prevalence of polyploidy in the plant kingdom suggests it as an important evolutionary feature for plant speciation and crop domestication. Studies of natural and synthetic polyploids have revealed rapid and dynamic changes in genomic structure and gene expression after polyploid formation. Growing evidence suggests that epigenetic modifications can alter homoeologous gene expression and reprogram gene expression networks, which allows polyploids to establish new cytotypes, grow vigorously and promote adaptation in local environments. Sequence and gene expression changes in polyploids have been well documented and reviewed elsewhere. This review is focused on developmental regulation and epigenetic changes including DNA methylation and histone modifications in polyploids.
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Affiliation(s)
- Qingxin Song
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, TX 78712, USA
| | - Z Jeffrey Chen
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, TX 78712, USA; State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
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111
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Mason AS, Pires JC. Unreduced gametes: meiotic mishap or evolutionary mechanism? Trends Genet 2015; 31:5-10. [DOI: 10.1016/j.tig.2014.09.011] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 09/22/2014] [Accepted: 09/24/2014] [Indexed: 10/24/2022]
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112
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Burgess MB, Cushman KR, Doucette ET, Talent N, Frye CT, Campbell CS. Effects of apomixis and polyploidy on diversification and geographic distribution in Amelanchier (Rosaceae). AMERICAN JOURNAL OF BOTANY 2014; 101:1375-87. [PMID: 25156985 DOI: 10.3732/ajb.1400113] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
UNLABELLED • PREMISE OF THE STUDY Amelanchier polyploid apomicts differ from sexual diploids in their more complex diversification, greater species problems, and geographic distribution. To understand these differences, we investigated the occurrence of polyploidy and frequency of apomixis. This research helps clarify species delimitation in an evolutionarily complex genus.• METHODS We used flow cytometry to estimate genome size of 1355 plants. We estimated the frequency of apomixis from flow-cytometrically determined ploidy levels of embryo and endosperm and from a progeny study using RAPD markers. We explored relationships of triploids to other ploidy levels and of ploidy levels to latitude plus elevation.• KEY RESULTS Diploids (32% of sample) and tetraploids (62%) were widespread. Triploids (6%) mostly occurred in small numbers with diploids from two or more species or with diploids and tetraploids. Seeds from diploids were 2% apomictic, the first report of apomixis in Amelanchier diploids. Seeds from triploids were 75% apomictic. We documented potential triploid bridge and triploid block from unbalanced endosperm and low pollen viability. Seeds from tetraploids were 97% apomictic, and tetraploids often formed microspecies. We did not find strong evidence for geographical parthenogenesis in North American Amelanchier. Most currently recognized species contained multiple ploidy levels that were morphologically semicryptic.• CONCLUSIONS Documentation of numerous transitions from diploidy to polyploidy helps clarify diversification, geographic distribution, and the species problem in Amelanchier. Despite the infrequent occurrence of triploids, their retention of 25% sexuality and capacity for triploid bridge may be important steps between sexual diploids and predominantly apomictic tetraploids.
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Affiliation(s)
- Michael B Burgess
- Department of Biological Sciences, State University of New York, Plattsburgh, Plattsburgh, New York 12901 USA
| | - Kevin R Cushman
- School of Biology and Ecology, University of Maine, Orono, Maine 04469 USA
| | - Eric T Doucette
- School of Biology and Ecology, University of Maine, Orono, Maine 04469 USA
| | - Nadia Talent
- Royal Ontario Museum, Department of Natural History, 100 Queen's Park, Toronto, M5S 2C6, Canada
| | - Christopher T Frye
- Maryland Department of Natural Resources, Natural Heritage Program, 909 Wye Mills Road, Wye Mills, Maryland 21679 USA
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113
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114
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Younis A, Hwang YJ, Lim KB. Exploitation of induced 2n-gametes for plant breeding. PLANT CELL REPORTS 2014; 33:215-23. [PMID: 24311154 DOI: 10.1007/s00299-013-1534-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 10/23/2013] [Accepted: 10/25/2013] [Indexed: 05/02/2023]
Abstract
Unreduced gamete formation derived via abnormal meiotic cell division is an important approach to polyploidy breeding. This process is considered the main driving force in spontaneous polyploids formation in nature, but the potential application of these gametes to plant breeding has not been fully exploited. An effective mechanism for their artificial induction is needed to attain greater genetic variation and enable efficient use of unreduced gametes in breeding programs. Different approaches have been employed for 2n-pollen production including interspecific hybridization, manipulation of environmental factors and treatment with nitrous oxide, trifluralin, colchicine, oryzalin and other chemicals. These chemicals can act as a stimulus to produce viable 2n pollen; however, their exact mode of action, optimum concentration and developmental stages are still not known. Identification of efficient methods of inducing 2n-gamete formation will help increase pollen germination of sterile interspecific hybrids for inter-genomic recombination and introgression breeding to develop new polyploid cultivars and increase heterozygosity among plant populations. Additionally, the application of genomic tools and identification and isolation of genes and mechanisms involved in the induction of 2n-gamete will enable increased exploitation in different plant species, which will open new avenues for plant breeding.
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Affiliation(s)
- Adnan Younis
- Department of Horticultural Science, Kyungpook National University, Daegu, 702-701, Korea,
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Sonnleitner M, Weis B, Flatscher R, García PE, Suda J, Krejčíková J, Schneeweiss GM, Winkler M, Schönswetter P, Hülber K. Parental ploidy strongly affects offspring fitness in heteroploid crosses among three cytotypes of autopolyploid Jacobaea carniolica (Asteraceae). PLoS One 2013; 8:e78959. [PMID: 24265735 PMCID: PMC3827125 DOI: 10.1371/journal.pone.0078959] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 09/17/2013] [Indexed: 11/25/2022] Open
Abstract
Reproductive interactions among cytotypes in their contact zones determine whether these cytotypes can co-exist and form stable contact zones or not. In autopolyploids, heteroploid cross-compatibilities might depend on parental ploidy, but tests of this hypothesis in autopolyploid systems with more than two ploidies are lacking. Here, we study Jacobaea carniolica, which comprises diploid, tetraploid, and hexaploid individuals regularly forming contact zones. Seeds obtained from in situ cross-pollinations within and among cytotypes were subjected to DNA flow cytometry and greenhouse germination experiments. Hybrid fitness and parental effects on hybrid fitness were tested with regression models comparing fitness parameters of early life stages. Irrespective of the direction of crosses, seed viability and seedling survival in diploid-polyploid crosses were substantially lower than in tetraploid-hexaploid crosses. In contrast, seedling growth traits indicated neither transgressive character expression nor any selection against hybrid offspring. Congruent with a model of genome dosage effects, these traits differed between reciprocal crosses, especially of diploids and tetraploids, where trait values resembled those of the maternal parent. The strong effect of parental ploidy on offspring fitness in heteroploid crosses may cause contact zones involving exclusively polyploid cytotypes to be less stable over longer terms than those involving diploids and polyploids.
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Affiliation(s)
- Michaela Sonnleitner
- Department of Systematic and Evolutionary Botany, University of Vienna, Vienna, Austria
- Department of Conservation Biology, Vegetation Ecology and Landscape Ecology, University of Vienna, Vienna, Austria
| | - Birgit Weis
- Department of Systematic and Evolutionary Botany, University of Vienna, Vienna, Austria
| | - Ruth Flatscher
- Department of Systematic and Evolutionary Botany, University of Vienna, Vienna, Austria
- Institute of Botany, University of Innsbruck, Innsbruck, Austria
| | - Pedro Escobar García
- Department of Systematic and Evolutionary Botany, University of Vienna, Vienna, Austria
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice, Czech Republic
| | - Jana Krejčíková
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice, Czech Republic
| | - Gerald M. Schneeweiss
- Department of Systematic and Evolutionary Botany, University of Vienna, Vienna, Austria
| | - Manuela Winkler
- Department of Systematic and Evolutionary Botany, University of Vienna, Vienna, Austria
| | | | - Karl Hülber
- Department of Conservation Biology, Vegetation Ecology and Landscape Ecology, University of Vienna, Vienna, Austria
- Vienna Institute for Nature Conservation & Analyses, Vienna, Austria
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Soper DM, Neiman M, Savytskyy OP, Zolan ME, Lively CM. Spermatozoa Production by Triploid Males in the New Zealand Freshwater Snail Potamopyrgus antipodarum.. Biol J Linn Soc Lond 2013; 110:227-234. [PMID: 24307744 PMCID: PMC3844136 DOI: 10.1111/bij.12085] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 03/03/2013] [Accepted: 03/05/2013] [Indexed: 11/28/2022]
Abstract
Asexual lineages derived from dioecious taxa are typically assumed to be all female. Even so, asexual females from a variety of animal taxa occasionally produce males. The existence of these males sets the stage for potential gene flow across asexual lineages as well as between sexual and asexual lineages. A recent study showed that asexual triploid female Potamopyrgus antipodarum, a New Zealand freshwater snail often used as a model to study sexual reproduction, occasionally produce triploid male offspring. Here, we show that these triploid male P. antipodarum 1) have testes that produce morphologically normal sperm, 2) make larger sperm cells that contain more nuclear DNA than the sperm produced by diploid sexual males, and 3) produce sperm that range in DNA content from haploid to diploid, and are often aneuploid. Analysis of meiotic chromosomes of triploid males showed that aberrant pairing during prophase I likely accounts for the high variation in DNA content among sperm. These results indicate that triploid male P. antipodarum produce sperm, but the extent to which these sperm are able to fertilize female ova remains unclear. Our results also suggest that the general assumption of sterility in triploid males should be more closely examined in other species in which such males are occasionally produced.
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Affiliation(s)
- Deanna M. Soper
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Maurine Neiman
- Department of Biology, University of Iowa, Iowa City, IA, USA
| | | | - Miriam E. Zolan
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Curt M. Lively
- Department of Biology, Indiana University, Bloomington, IN, USA
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Nemorin A, David J, Maledon E, Nudol E, Dalon J, Arnau G. Microsatellite and flow cytometry analysis to help understand the origin of Dioscorea alata polyploids. ANNALS OF BOTANY 2013; 112:811-9. [PMID: 23912697 PMCID: PMC3747798 DOI: 10.1093/aob/mct145] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 05/15/2013] [Indexed: 05/30/2023]
Abstract
BACKGROUND AND AIMS Dioscorea alata is a polyploid species with a ploidy level ranging from diploid (2n = 2x = 40) to tetraploid (2n = 4x = 80). Ploidy increase is correlated with better agronomic performance. The lack of knowledge about the origin of D. alata spontaneous polyploids (triploids and tetraploids) limits the efficiency of polyploid breeding. The objective of the present study was to use flow cytometry and microsatellite markers to understand the origin of D. alata polyploids. METHODS Different progeny generated by intracytotype crosses (2x × 2x) and intercytotype crosses (2x × 4x and 3x × 2x) were analysed in order to understand endosperm incompatibility phenomena and gamete origins via the heterozygosity rate transmitted to progeny. RESULTS This work shows that in a 2x × 2x cross, triploids with viable seeds are obtained only via a phenomenon of diploid female non-gametic reduction. The study of the transmission of heterozygosity made it possible to exclude polyspermy and polyembryony as the mechanisms at the origin of triploids. The fact that no seedlings were obtained by a 3x × 2x cross made it possible to confirm the sterility of triploid females. Flow cytometry analyses carried out on the endosperm of seeds resulting from 2x × 4x crosses revealed endosperm incompatibility phenomena. CONCLUSIONS The major conclusion is that the polyploids of D. alata would have appeared through the formation of unreduced gametes. The triploid pool would have been built and diversified through the formation of 2n gametes in diploid females as the result of the non-viability of seeds resulting from the formation of 2n sperm and of the non-viability of intercytotype crosses. The tetraploids would have appeared through bilateral sexual polyploidization via the union of two unreduced gametes due to the sterility of triploids.
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Affiliation(s)
- A. Nemorin
- CIRAD (Centre de Coopération Internationale en Recherche Agronomique pour le Développement), Station de Roujol, 97170 Petit Bourg, Guadeloupe, France
| | - J. David
- UMR AGAP, Montpellier Supagro, 2, place Viala, 34060 Montpellier Cedex 2, France
| | - E. Maledon
- CIRAD (Centre de Coopération Internationale en Recherche Agronomique pour le Développement), Station de Roujol, 97170 Petit Bourg, Guadeloupe, France
| | - E. Nudol
- CIRAD (Centre de Coopération Internationale en Recherche Agronomique pour le Développement), Station de Roujol, 97170 Petit Bourg, Guadeloupe, France
| | - J. Dalon
- CIRAD (Centre de Coopération Internationale en Recherche Agronomique pour le Développement), Station de Roujol, 97170 Petit Bourg, Guadeloupe, France
| | - G. Arnau
- CIRAD (Centre de Coopération Internationale en Recherche Agronomique pour le Développement), Station de Roujol, 97170 Petit Bourg, Guadeloupe, France
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118
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Wijnker E, Schnittger A. Control of the meiotic cell division program in plants. PLANT REPRODUCTION 2013; 26:143-58. [PMID: 23852379 PMCID: PMC3747318 DOI: 10.1007/s00497-013-0223-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 06/23/2013] [Indexed: 05/02/2023]
Abstract
While the question of why organisms reproduce sexually is still a matter of controversy, it is clear that the foundation of sexual reproduction is the formation of gametes with half the genomic DNA content of a somatic cell. This reduction in genomic content is accomplished through meiosis that, in contrast to mitosis, comprises two subsequent chromosome segregation steps without an intervening S phase. In addition, meiosis generates new allele combinations through the compilation of new sets of homologous chromosomes and the reciprocal exchange of chromatid segments between homologues. Progression through meiosis relies on many of the same, or at least homologous, cell cycle regulators that act in mitosis, e.g., cyclin-dependent kinases and the anaphase-promoting complex/cyclosome. However, these mitotic control factors are often differentially regulated in meiosis. In addition, several meiosis-specific cell cycle genes have been identified. We here review the increasing knowledge on meiotic cell cycle control in plants. Interestingly, plants appear to have relaxed cell cycle checkpoints in meiosis in comparison with animals and yeast and many cell cycle mutants are viable. This makes plants powerful models to study meiotic progression and allows unique modifications to their meiotic program to develop new plant-breeding strategies.
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Affiliation(s)
- Erik Wijnker
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg, France
- Trinationales Institut für Pflanzenforschung, Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg, France
| | - Arp Schnittger
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg, France
- Trinationales Institut für Pflanzenforschung, Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg, France
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119
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Weiss-Schneeweiss H, Emadzade K, Jang TS, Schneeweiss G. Evolutionary consequences, constraints and potential of polyploidy in plants. Cytogenet Genome Res 2013; 140:137-50. [PMID: 23796571 PMCID: PMC3859924 DOI: 10.1159/000351727] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Polyploidy, the possession of more than 2 complete genomes, is a major force in plant evolution known to affect the genetic and genomic constitution and the phenotype of an organism, which will have consequences for its ecology and geography as well as for lineage diversification and speciation. In this review, we discuss phylogenetic patterns in the incidence of polyploidy including possible underlying causes, the role of polyploidy for diversification, the effects of polyploidy on geographical and ecological patterns, and putative underlying mechanisms as well as chromosome evolution and evolution of repetitive DNA following polyploidization. Spurred by technological advances, a lot has been learned about these aspects both in model and increasingly also in nonmodel species. Despite this enormous progress, long-standing questions about polyploidy still cannot be unambiguously answered, due to frequently idiosyncratic outcomes and insufficient integration of different organizational levels (from genes to ecology), but likely this will change in the near future. See also the sister article focusing on animals by Choleva and Janko in this themed issue.
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Affiliation(s)
- H. Weiss-Schneeweiss
- Department of Systematic and Evolutionary Botany University of Vienna, Rennweg 14 AT–1030 Vienna (Austria)
| | - K. Emadzade
- Department of Systematic and Evolutionary Botany University of Vienna, Rennweg 14 AT–1030 Vienna (Austria)
| | - T.-S. Jang
- Department of Systematic and Evolutionary Botany University of Vienna, Rennweg 14 AT–1030 Vienna (Austria)
| | - G.M. Schneeweiss
- Department of Systematic and Evolutionary Botany University of Vienna, Rennweg 14 AT–1030 Vienna (Austria)
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120
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Tayalé A, Parisod C. Natural pathways to polyploidy in plants and consequences for genome reorganization. Cytogenet Genome Res 2013; 140:79-96. [PMID: 23751271 DOI: 10.1159/000351318] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The last decade highlighted polyploidy as a rampant evolutionary process that triggers drastic genome reorganization, but much remains to be understood about their causes and consequences in both autopolyploids and allopolyploids. Here, we provide an overview of the current knowledge on the pathways leading to different types of polyploids and patterns of polyploidy-induced genome restructuring and functional changes in plants. Available evidence leads to a tentative 'diverge, merge and diverge' model supporting polyploid speciation and stressing patterns of divergence between diploid progenitors as a suitable predictor of polyploid genome reorganization. The merging of genomes at the origin of a polyploid lineage may indeed reveal different kinds of incompatibilities (chromosomal, genic and transposable elements) that have accumulated in diverging progenitors and reduce the fitness of nascent polyploids. Accordingly, successful polyploids have to overcome these incompatibilities through non-Mendelian mechanisms, fostering polyploid genome reorganization in association with the establishment of new lineages. See also sister article focusing on animals by Collares-Pereira et al., in this themed issue.
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Affiliation(s)
- A Tayalé
- Laboratory of Evolutionary Botany, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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121
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Sanetomo R, Hosaka K. Pollen transcriptome analysis of Solanum tuberosum (2n = 4x = 48), S. demissum (2n = 6x = 72), and their reciprocal F1 hybrids. PLANT CELL REPORTS 2013; 32:623-636. [PMID: 23430172 DOI: 10.1007/s00299-013-1395-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 01/23/2013] [Accepted: 02/04/2013] [Indexed: 06/01/2023]
Abstract
Pollen mRNAs were different in reciprocal F 1 hybrids, which were probably caused by a cytoplasm-nuclear chromosomal genes interaction. We have found reciprocal differences in crossability between F1 hybrids of Solanum tuberosum (T) and a Mexican wild potato species S. demissum (D). When the reciprocal hybrids were crossed as pollen parents with S. demissum, a significantly higher berry-setting rate was obtained in TD compared with DT. In this study, we performed a whole-genome transcript analysis of the pollen mRNA using a high-throughput sequencer. We obtained 12.6 billion bases that were aligned into 13,020 transcripts with 9,366 loci. All possible genetic modes were observed between the parents and their progeny, where over-dominance and under-recessive types were relatively frequent (15.7 and 15.3 %, respectively). We found that 59.1 % of transcripts were more abundant in TD and over fourfold higher transcription levels were found in 66 TD transcripts and three DT transcripts. A higher proportion of over-dominance and a lower proportion of under-recessive transcription types were also observed in TD. The percentage contributions of multiple transcripts at the same locus varied greatly and were transcribed differently between species. In the new allelic combinations created by hybridization, approximately three-fourth of the transcripts had intermediate percentage contributions between the parents but no differential transcription patterns were apparent between the reciprocal hybrids. A broad spectrum of functionally different nuclear genes was over-represented in TD pollen, some of which were directly related to pollen behavior. Since TD and DT pollen had the same composition of nuclear genes, a cytoplasm-nuclear chromosomal genes interaction is suggested for the cause of transcriptional and phenotypic differences between reciprocal hybrids.
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Affiliation(s)
- Rena Sanetomo
- NARO Hokkaido Agricultural Research Center, Shinsei, Memuro, Hokkaido, 082-0081, Japan
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Duszynska D, McKeown PC, Juenger TE, Pietraszewska-Bogiel A, Geelen D, Spillane C. Gamete fertility and ovule number variation in selfed reciprocal F1 hybrid triploid plants are heritable and display epigenetic parent-of-origin effects. THE NEW PHYTOLOGIST 2013; 198:71-81. [PMID: 23368793 DOI: 10.1111/nph.12147] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Accepted: 12/08/2012] [Indexed: 05/10/2023]
Abstract
Polyploidy and hybridization play major roles in plant evolution and reproduction. To investigate the reproductive effects of polyploidy and hybridization in Arabidopsis thaliana, we analyzed fertility of reciprocal pairs of F1 hybrid triploids, generated by reciprocally crossing 89 diploid accessions to a tetraploid Ler-0 line. All F1 hybrid triploid genotypes exhibited dramatically reduced ovule fertility, while variation in ovule number per silique was observed across different F1 triploid genotypes. These two reproductive traits were negatively correlated suggesting a trade-off between increased ovule number and ovule fertility. Furthermore, the ovule fertility of the F1 hybrid triploids displayed both hybrid dysgenesis and hybrid advantage (heterosis) effects. Strikingly, both reproductive traits (ovule fertility, ovule number) displayed epigenetic parent-of-origin effects between genetically identical reciprocal F1 hybrid triploid pairs. In some F1 triploid genotypes, the maternal genome excess F1 hybrid triploid was more fertile, whilst for other accessions the paternal genome excess F1 hybrid triploid was more fertile. Male gametogenesis was not significantly disrupted in F1 triploids. Fertility variation in the F1 triploid A. thaliana is mainly the result of disrupted ovule development. Overall, we demonstrate that in F1 triploid plants both ovule fertility and ovule number are subject to parent-of-origin effects that are genome dosage-dependent.
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Affiliation(s)
- Dorota Duszynska
- Plant and AgriBiosciences Centre (PABC), School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Peter C McKeown
- Plant and AgriBiosciences Centre (PABC), School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Thomas E Juenger
- Section of Integrative Biology & Institute for Cellular and Molecular Biology, University of Texas, 1 University Station C0930, Austin, TX, USA
| | - Anna Pietraszewska-Bogiel
- Plant and AgriBiosciences Centre (PABC), School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
- Molecular Cytology, Swammerdam Institute for Life Sciences (SILS), University of Amsterdam, Science Park 904, 1098XH, Amsterdam, the Netherlands
| | - Danny Geelen
- Department of Plant Production, Faculty of Bioscience Engineering, University of Ghent, 9000, Ghent, Belgium
| | - Charles Spillane
- Plant and AgriBiosciences Centre (PABC), School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
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Watching the grin fade: tracing the effects of polyploidy on different evolutionary time scales. Semin Cell Dev Biol 2013; 24:320-31. [PMID: 23466286 DOI: 10.1016/j.semcdb.2013.02.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 02/05/2013] [Accepted: 02/07/2013] [Indexed: 12/13/2022]
Abstract
Polyploidy, or whole-genome duplication (WGD), is a recurrent mutation both in cell lineages and over evolutionary time. By globally changing the relationship between gene copy number and other cellular entities, it can induce dramatic changes at the cellular and phenotypic level. Perhaps surprisingly, then, the insights that these events can bring to understanding other cellular features are not as well appreciated as they could be. In this review, we draw on examples of polyploidy from animals, plants and yeast to explore how investigations of polyploid cells have improved our understanding of the cell cycle, biological network complexity, metabolic phenotypes and tumor biology. We argue that the study of polyploidy across organisms, cell types, and time scales serves not only as a window into basic cell biology, but also as a basis for a predictive biology with applications ranging from crop improvement to treating cancer.
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124
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De Storme N, Copenhaver GP, Geelen D. Production of diploid male gametes in Arabidopsis by cold-induced destabilization of postmeiotic radial microtubule arrays. PLANT PHYSIOLOGY 2012; 160:1808-26. [PMID: 23096158 PMCID: PMC3510112 DOI: 10.1104/pp.112.208611] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 10/24/2012] [Indexed: 05/18/2023]
Abstract
Whole-genome duplication through the formation of diploid gametes is a major route for polyploidization, speciation, and diversification in plants. The prevalence of polyploids in adverse climates led us to hypothesize that abiotic stress conditions can induce or stimulate diploid gamete production. In this study, we show that short periods of cold stress induce the production of diploid and polyploid pollen in Arabidopsis (Arabidopsis thaliana). Using a combination of cytological and genetic analyses, we demonstrate that cold stress alters the formation of radial microtubule arrays at telophase II and consequently leads to defects in postmeiotic cytokinesis and cell wall formation. As a result, cold-stressed male meiosis generates triads, dyads, and monads that contain binuclear and polynuclear microspores. Fusion of nuclei in binuclear and polynuclear microspores occurs spontaneously before pollen mitosis I and eventually leads to the formation of diploid and polyploid pollen grains. Using segregation analyses, we also found that the majority of cold-induced dyads and triads are genetically equivalent to a second division restitution and produce diploid gametes that are highly homozygous. In a broader perspective, these findings offer insights into the fundamental mechanisms that regulate male gametogenesis in plants and demonstrate that their sensitivity to environmental stress has evolutionary significance and agronomic relevance in terms of polyploidization.
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Affiliation(s)
- Nico De Storme
- Department of Plant Production, Faculty of Bioscience Engineering, University of Ghent, 9000 Ghent, Belgium (N.D.S., D.G.); Department of Biology and Carolina Center for Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599 (G.P.C.); and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599 (G.P.C.)
| | - Gregory P. Copenhaver
- Department of Plant Production, Faculty of Bioscience Engineering, University of Ghent, 9000 Ghent, Belgium (N.D.S., D.G.); Department of Biology and Carolina Center for Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599 (G.P.C.); and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599 (G.P.C.)
| | - Danny Geelen
- Department of Plant Production, Faculty of Bioscience Engineering, University of Ghent, 9000 Ghent, Belgium (N.D.S., D.G.); Department of Biology and Carolina Center for Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599 (G.P.C.); and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599 (G.P.C.)
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Abstract
Hybridisation among taxa with different ploidy levels is often associated with hybrid sterility. Clonal reproduction can stabilise these hybrids, but pervasive clonality may have a profound impact on the distribution of genetic diversity in natural populations. Here we investigate a widespread triploid taxon resulting from hybridisation between diploid Mimulus guttatus and tetraploid Mimulus luteus, two species that were introduced into the United Kingdom (UK) in the nineteenth century. This hybrid, Mimulus x robertsii, is largely sterile but capable of prolific vegetative propagation and has been recorded in the wild since 1872. We surveyed 40 Mimulus populations from localities across the UK to examine the current incidence of hybrids, and selected seventeen populations for genetic analysis using codominant markers. Cluster analyses revealed two main groups of genetically distinct individuals, corresponding to either diploid (M. guttatus) or polyploid (M. luteus and M. x robertsii) samples. Triploid hybrids were found in around 50% of sampled sites, sometimes coexisting with one of the parental species (M. guttatus). The other parent, M. luteus, was restricted to a single locality. Individual populations of M. x robertsii were genetically variable, containing multiple, highly heterozygous clones, with the majority of genetic variation distributed among- rather than within populations. Our findings demonstrate that this largely sterile, clonal taxon can preserve non-negligible amounts of genetic variation. The presence of genetically variable hybrid populations may provide the material for the continued success of asexual taxa in diverse environments.
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Schatlowski N, Köhler C. Tearing down barriers: understanding the molecular mechanisms of interploidy hybridizations. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:6059-67. [PMID: 23105129 DOI: 10.1093/jxb/ers288] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Polyploidization, the process leading to more than two sets of chromosomes, is widely recognized as a major speciation mechanism that might hold the key to Darwin's 'abominable mystery', as he referred to the sudden rise of angiosperms to ecological dominance. On their way to become polyploid most plants take the route through the production of unreduced gametes that might eventually lead to viable triploid intermediates able to backcross or self-fertilize to give rise to stable polyploid plants. Polyploids are almost instantly reproductively isolated from their non-polyploid ancestors; as hybridizations of species that differ in ploidy mostly lead to non-viable progeny. This immediate reproductive barrier referred to as 'triploid block' is established in the endosperm, pointing towards an important but greatly underestimated role of the endosperm in preventing interploidy hybridizations. Parent-of-origin specific gene expression occurs predominantly in the endosperm and might cause the dosage-sensitivity of the endosperm. This article illustrates, based on the recent molecular and genetic findings mainly gained in the model species Arabidopsis thaliana, the 'journey' of unreduced gametes to triploid intermediates to polyploid plants and will also discuss the implications for interploidy and interspecies hybridizations.
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Affiliation(s)
- Nicole Schatlowski
- Department of Plant Biology and Forest Genetics, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center of Plant Biology, 750 07 Uppsala, Sweden
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Stoute AI, Varenko V, King GJ, Scott RJ, Kurup S. Parental genome imbalance in Brassica oleracea causes asymmetric triploid block. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 71:503-16. [PMID: 22679928 DOI: 10.1111/j.1365-313x.2012.05015.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Interploidy crosses fail in many plant species due to abnormalities in endosperm development. In the inbreeding species Arabidopsis thaliana, both paternal and maternal excess interploidy crosses usually result in viable seed that exhibit parent-of-origin effects on endosperm development and final seed size. Paternal excess crosses result in extended proliferation of the endosperm and larger seeds, while conversely maternal excess crosses result in early endosperm cellularisation and smaller seeds. Investigations into the effect of parental gene dosage on seed development have revealed that MADS box transcription factors, particularly the AGAMOUS-like family, play important roles in controlling endosperm proliferation. The important crop genus Brassica contains self-incompatible outbreeding species and has a larger and more complex genome than the closely related Arabidopsis. Here we show that although Brassica oleracea displays strong parent-of-origin effects on seed development, triploid block due to lethal disruption of endosperm development was restricted to paternal excess, with maternal excess crosses yielding viable seed. In addition, transcriptome analyses of Brassica homologues of Arabidopsis genes linked to parent-of-origin effects revealed conservation of some mechanisms controlling aspects endosperm behaviour in the two species. However, there were also differences that may explain the failure of the paternal excess cross in B. oleracea.
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Affiliation(s)
- Andrew I Stoute
- Department of Plant Sciences, Rothamsted Research, Harpenden AL5 2JQ, UK
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Osabe K, Kawanabe T, Sasaki T, Ishikawa R, Okazaki K, Dennis ES, Kazama T, Fujimoto R. Multiple mechanisms and challenges for the application of allopolyploidy in plants. Int J Mol Sci 2012; 13:8696-8721. [PMID: 22942729 PMCID: PMC3430260 DOI: 10.3390/ijms13078696] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 07/04/2012] [Accepted: 07/04/2012] [Indexed: 11/16/2022] Open
Abstract
An allopolyploid is an individual having two or more complete sets of chromosomes derived from different species. Generation of allopolyploids might be rare because of the need to overcome limitations such as co-existing populations of parental lines, overcoming hybrid incompatibility, gametic non-reduction, and the requirement for chromosome doubling. However, allopolyploids are widely observed among plant species, so allopolyploids have succeeded in overcoming these limitations and may have a selective advantage. As techniques for making allopolyploids are developed, we can compare transcription, genome organization, and epigenetic modifications between synthesized allopolyploids and their direct parental lines or between several generations of allopolyploids. It has been suggested that divergence of transcription caused either genetically or epigenetically, which can contribute to plant phenotype, is important for the adaptation of allopolyploids.
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Affiliation(s)
- Kenji Osabe
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Plant Industry, Canberra, ACT 2601, Australia; E-Mails: (K.O.); (E.S.D.)
| | - Takahiro Kawanabe
- Watanabe Seed Co., Ltd, Machiyashiki, Misato-cho, Miyagi 987-8607, Japan; E-Mail:
| | - Taku Sasaki
- Watanabe Seed Co., Ltd, Machiyashiki, Misato-cho, Miyagi 987-8607, Japan; E-Mail:
| | - Ryo Ishikawa
- Laboratory of Plant Breeding, Graduate School of Agricultural Science, Kobe University, Nada, Kobe 657-8510, Japan; E-Mail:
- Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Colney, Norwich, NR4 7UH, UK; E-Mail:
| | - Keiichi Okazaki
- Graduate School of Science and Technology, Niigata University, Ikarashi-ninocho, Niigata 950-2181, Japan; E-Mail:
| | - Elizabeth S. Dennis
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Plant Industry, Canberra, ACT 2601, Australia; E-Mails: (K.O.); (E.S.D.)
| | - Tomohiko Kazama
- Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai 981-8555, Japan; E-Mail:
| | - Ryo Fujimoto
- Graduate School of Science and Technology, Niigata University, Ikarashi-ninocho, Niigata 950-2181, Japan; E-Mail:
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129
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Vallejo-Marín M. Mimulus peregrinus (Phrymaceae): A new British allopolyploid species. PHYTOKEYS 2012; 14:1-14. [PMID: 23170069 PMCID: PMC3492922 DOI: 10.3897/phytokeys.14.3305] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Accepted: 07/02/2012] [Indexed: 05/23/2023]
Abstract
Polyploidization plays an important role in species formation as chromosome doubling results in strong reproductive isolation between derivative and parental taxa. In this note I describe a new species, Mimulus peregrinus (Phrymaceae), which represents the first recorded instance of a new British polyploid species of Mimulus (2n = 6x = 92) that has arisen since the introduction of this genus into the United Kingdom in the 1800's. Mimulus peregrinus presents floral and vegetative characteristics intermediate between Mimulus guttatus and Mimulus luteus, but can be distinguished from all naturalized British Mimulus species and hybrids based on a combination of reproductive and vegetative traits. Mimulus peregrinus displays high pollen and seed fertility as well as traits usually associated with genome doubling such as increased pollen and stomata size. The intermediate characteristics of Mimulus peregrinus between Mimulus guttatus (2n = 2x = 28)and Mimulus luteus (2n = 4x = 60-62), and its close affinity with the highly sterile, triploid (2n = 3x = 44-45) hybrid taxon Mimulus × robertsii (Mimulus guttatus × Mimulus luteus), suggests that Mimulus peregrinus mayconstitute an example of recent allopolyploid speciation.
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Affiliation(s)
- Mario Vallejo-Marín
- Biological and Environmental Sciences, University of Stirling. Stirling, Scotland. FK9 4LA
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130
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Muyle A, Zemp N, Deschamps C, Mousset S, Widmer A, Marais GAB. Rapid de novo evolution of X chromosome dosage compensation in Silene latifolia, a plant with young sex chromosomes. PLoS Biol 2012; 10:e1001308. [PMID: 22529744 PMCID: PMC3328428 DOI: 10.1371/journal.pbio.1001308] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Accepted: 03/01/2012] [Indexed: 11/18/2022] Open
Abstract
Silene latifolia is a dioecious plant with heteromorphic sex chromosomes that have originated only ∼10 million years ago and is a promising model organism to study sex chromosome evolution in plants. Previous work suggests that S. latifolia XY chromosomes have gradually stopped recombining and the Y chromosome is undergoing degeneration as in animal sex chromosomes. However, this work has been limited by the paucity of sex-linked genes available. Here, we used 35 Gb of RNA-seq data from multiple males (XY) and females (XX) of an S. latifolia inbred line to detect sex-linked SNPs and identified more than 1,700 sex-linked contigs (with X-linked and Y-linked alleles). Analyses using known sex-linked and autosomal genes, together with simulations indicate that these newly identified sex-linked contigs are reliable. Using read numbers, we then estimated expression levels of X-linked and Y-linked alleles in males and found an overall trend of reduced expression of Y-linked alleles, consistent with a widespread ongoing degeneration of the S. latifolia Y chromosome. By comparing expression intensities of X-linked alleles in males and females, we found that X-linked allele expression increases as Y-linked allele expression decreases in males, which makes expression of sex-linked contigs similar in both sexes. This phenomenon is known as dosage compensation and has so far only been observed in evolutionary old animal sex chromosome systems. Our results suggest that dosage compensation has evolved in plants and that it can quickly evolve de novo after the origin of sex chromosomes.
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Affiliation(s)
- Aline Muyle
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
| | - Niklaus Zemp
- Institute of Integrative Biology (IBZ), ETH Zurich, Zürich, Switzerland
| | | | - Sylvain Mousset
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
| | - Alex Widmer
- Institute of Integrative Biology (IBZ), ETH Zurich, Zürich, Switzerland
- * E-mail: (GABM); (AW)
| | - Gabriel A. B. Marais
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
- * E-mail: (GABM); (AW)
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131
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Ricca M, Szövényi P, Temsch EM, Johnson MG, Shaw AJ. Interploidal hybridization and mating patterns in the Sphagnum subsecundum complex. Mol Ecol 2011; 20:3202-18. [PMID: 21722226 DOI: 10.1111/j.1365-294x.2011.05170.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Polyploidization is thought to result in instant sympatric speciation, but several cases of hybrid zones between one of the parental species and its polyploid derivative have been documented. Previous work showed that diploid Sphagnum lescurii is an allopolyploid derived from the haploids S. lescurii (maternal progenitor) and S. subsecundum (paternal progenitor). Here, we report the results from analyses of a population where allodiploid and haploid S. lescurii co-occur and produce sporophytes. We tested (i) whether haploids and diploids form hybrid triploid sporophytes; (ii) how hybrid and nonhybrid sporophytes compare in fitness; (iii) whether hybrid sporophytes form viable spores; (iv) the ploidy of any viable gametophyte offspring from hybrid sporophytes; (v) the relative viability of sporelings derived from hybrid and nonhybrid sporophytes; and (vi) if interploidal hybridization results in introgression between the allopolyploid and its haploid progenitor. We found that triploid hybrid sporophytes do occur and are larger than nonhybrid sporophytes, but exhibit very low germination percentages and produce sporelings that develop more slowly than those from nonhybrid sporophytes. All sporophytes attached to haploid gametophytes were triploid and were sired by diploid males, but all sporophytes attached to diploid gametophytes were tetraploid. This asymmetric pattern of interploidal hybridization is related to an absence of haploid male gametophytes in the population. Surprisingly, all sporelings from triploid sporophytes were triploid, yet were genetically variable, suggesting some form of aberrant meiosis that warrants further study. There was limited (but some) evidence of introgression between allodiploid and haploid S. lescurii.
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Affiliation(s)
- M Ricca
- Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, Porto, Portugal.
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132
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Mason AS, Nelson MN, Yan G, Cowling WA. Production of viable male unreduced gametes in Brassica interspecific hybrids is genotype specific and stimulated by cold temperatures. BMC PLANT BIOLOGY 2011; 11:103. [PMID: 21663695 PMCID: PMC3141635 DOI: 10.1186/1471-2229-11-103] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 06/12/2011] [Indexed: 05/18/2023]
Abstract
BACKGROUND Unreduced gametes (gametes with the somatic chromosome number) may provide a pathway for evolutionary speciation via allopolyploid formation. We evaluated the effect of genotype and temperature on male unreduced gamete formation in Brassica allotetraploids and their interspecific hybrids. The frequency of unreduced gametes post-meiosis was estimated in sporads from the frequency of dyads or giant tetrads, and in pollen from the frequency of viable giant pollen compared with viable normal pollen. Giant tetrads were twice the volume of normal tetrads, and presumably resulted from pre-meiotic doubling of chromosome number. Giant pollen was defined as pollen with more than 1.5 × normal diameter, under the assumption that the doubling of DNA content in unreduced gametes would approximately double the pollen cell volume. The effect of genotype was assessed in five B. napus, two B. carinata and one B. juncea parents and in 13 interspecific hybrid combinations. The effect of temperature was assessed in a subset of genotypes in hot (day/night 30°C/20°C), warm (25°C/15°C), cool (18°C/13°C) and cold (10°C/5°C) treatments. RESULTS Based on estimates at the sporad stage, some interspecific hybrid genotypes produced unreduced gametes (range 0.06 to 3.29%) at more than an order of magnitude higher frequency than in the parents (range 0.00% to 0.11%). In nine hybrids that produced viable mature pollen, the frequency of viable giant pollen (range 0.2% to 33.5%) was much greater than in the parents (range 0.0% to 0.4%). Giant pollen, most likely formed from unreduced gametes, was more viable than normal pollen in hybrids. Two B. napus × B. carinata hybrids produced 9% and 23% unreduced gametes based on post-meiotic sporad observations in the cold temperature treatment, which was more than two orders of magnitude higher than in the parents. CONCLUSIONS These results demonstrate that sources of unreduced gametes, required for the triploid bridge hypothesis of allopolyploid evolution, are readily available in some Brassica interspecific hybrid genotypes, especially at cold temperatures.
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Affiliation(s)
- Annaliese S Mason
- School of Plant Biology M084 and The UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Matthew N Nelson
- School of Plant Biology M084 and The UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Guijun Yan
- School of Plant Biology M084 and The UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Wallace A Cowling
- School of Plant Biology M084 and The UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
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133
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De Storme N, Geelen D. The Arabidopsis mutant jason produces unreduced first division restitution male gametes through a parallel/fused spindle mechanism in meiosis II. PLANT PHYSIOLOGY 2011; 155:1403-15. [PMID: 21257792 PMCID: PMC3046594 DOI: 10.1104/pp.110.170415] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 01/20/2011] [Indexed: 05/18/2023]
Abstract
In plants, whole-genome doubling (polyploidization) is a widely occurring process largely contributing to plant evolution and diversification. The generation and fusion of diploid gametes is now considered the major route of plant polyploidization. The parallel arrangement or fusion of meiosis II MII spindles (ps) is one of the most frequently reported mechanisms generating triploid offspring. Through a forward genetics screen of an Arabidopsis (Arabidopsis thaliana) ethyl methanesulfonate population, we identified Arabidopsis thaliana Parallel Spindles1 (AtPS1), which was recently reported as a major gene implicated in the control of the ps meiotic defect. In addition, we describe the isolation and characterization of a novel allele of JASON, involved in male gametophytic ploidy regulation in plants. Similar to atps1 mutants, jason produces more than 25% 2n pollen grains and spontaneously forms triploid offspring. By combining both cytological and genetic approaches, we demonstrate that loss of JASON causes the formation of parallel arranged and fused spindles in male MII, resulting in the production of unreduced first division restitution 2n spores. Although JASON encodes a protein of unknown function, we additionally show that the meiotic ps defect in jason is caused by a reduction in AtPS1 transcript levels, indicating that JASON positively regulates AtPS1 expression, allowing the proper organization and orientation of metaphase II spindle plates in MII.
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Affiliation(s)
| | - Danny Geelen
- Department of Plant Production, Faculty of Bioscience Engineering, University of Ghent, 9000 Ghent, Belgium
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134
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Brownfield L, Köhler C. Unreduced gamete formation in plants: mechanisms and prospects. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:1659-68. [PMID: 21109579 DOI: 10.1093/jxb/erq371] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Polyploids, organisms with more than two sets of chromosomes, are widespread in flowering plants, including many important crop species. Increases in ploidy level are believed to arise commonly through the production of gametes that have not had their ploidy level reduced during meiosis. Although there have been cytological descriptions of unreduced gamete formation in a number of plants, until recently none of the underlying genes or molecular mechanisms involved in unreduced gamete production have been described. The recent discovery of several genes in which mutations give rise to a high frequency of unreduced gametes in the model plant Arabidopsis thaliana opens the door to the elucidation of this important event and its manipulation in crop species. Here this recent progress is reviewed and the identified genes and the mechanism by which the loss of protein function leads to the formation of unreduced gametes are discussed. The potential to use the knowledge gained from Arabidopsis mutants to design tools and develop techniques to engineer unreduced gamete production in important crop species for use in plant breeding is also discussed.
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Affiliation(s)
- Lynette Brownfield
- Department of Biology and Zurich-Basel Plant Science Center, Swiss Federal Institute of Technology, ETH Centre, Zurich, Switzerland
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135
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Trávníček P, Dočkalová Z, Rosenbaumová R, Kubátová B, Szeląg Z, Chrtek J. Bridging global and microregional scales: ploidy distribution in Pilosella echioides (Asteraceae) in central Europe. ANNALS OF BOTANY 2011; 107:443-54. [PMID: 21208933 PMCID: PMC3043935 DOI: 10.1093/aob/mcq260] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 11/02/2010] [Accepted: 11/24/2010] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS A detailed knowledge of cytotype distribution can provide important insights into the evolutionary history of polyploid systems. This study aims to explore the spatial distribution of different cytotypes in Pilosella echioides at various spatial scales (from the whole distributional range to the population level) and to outline possible evolutionary scenarios for the observed geographic pattern. METHODS DNA-ploidy levels were estimated using DAPI flow cytometry in 4410 individuals of P. echioides from 46 populations spread over the entire distribution range in central Europe. Special attention was paid to the cytotype structure in the most ploidy-diverse population in south-west Moravia. KEY RESULTS Five different cytotypes (2x, 3x, 4x, 5x and 6x) were found, the last being recorded for the first time. Although ploidy-uniform (di- or tetraploid) sites clearly prevailed, nearly one-quarter of the populations investigated harboured more (up to all five) cytotypes. Whereas penta- and hexaploids constituted only a minority of the samples, a striking predominance of the triploid cytotype was observed in several populations. CONCLUSIONS The representative sampling confirmed previous data on cytotype distribution, i.e. the spatial aggregation of mixed-ploidy populations in south-west Moravia and Lower Austria and the predominance of ploidy-uniform populations in other parts of the area investigated. Recurrent origin of polyploids from diploid progenitors via unreduced gametes and their successful establishment are considered the key factors promoting intrapopulational ploidy mixture ('primary hybrid zones'). As an alternative to the generally accepted theory of cytotype co-existence based on the development of different means of inter-ploidy reproductive isolation, it is suggested that a long-term ploidy mixture can also be maintained in free-mating populations provided that the polyploids originate with a sufficient frequency. In addition, the prevalence (or subdominance) of the triploid cytotype in several mixed-ploidy populations represents the first evidence of such a phenomenon in plant systems with exclusively sexual reproduction.
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Affiliation(s)
- Pavel Trávníček
- Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic
| | - Zuzana Dočkalová
- Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
| | - Radka Rosenbaumová
- Department of Botany, Natural History Museum, National Museum, CZ-193 00 Prague - Horní Počernice, Czech Republic
| | - Barbora Kubátová
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic
- Biotechnological Centre, Faculty of Agriculture, University of South Bohemia, CZ-370 05 České Budějovice, Czech Republic
| | - Zbigniew Szeląg
- Institute of Botany, Jagiellonian University, Kopernika 31, PL-315 01 Kraków, Poland
| | - Jindřich Chrtek
- Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic
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136
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Sonnleitner M, Flatscher R, Escobar García P, Rauchová J, Suda J, Schneeweiss GM, Hülber K, Schönswetter P. Distribution and habitat segregation on different spatial scales among diploid, tetraploid and hexaploid cytotypes of Senecio carniolicus (Asteraceae) in the Eastern Alps. ANNALS OF BOTANY 2010; 106:967-77. [PMID: 20880930 PMCID: PMC2990664 DOI: 10.1093/aob/mcq192] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 07/27/2010] [Accepted: 08/24/2010] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS The spatial distribution of cytotypes can provide valuable insights into evolutionary patterns of polyploid complexes. In a previous study the macro-scale distribution of the three main cytotypes in Senecio carniolicus (Asteraceae) within the Eastern Alps was characterized. Employing a roughly 12-fold extended sampling, the present study focuses on unravelling patterns of cytotype distribution on the meso- and microscale and on correlating those with ecological properties of the growing sites. METHODS DAPI flow cytometry of dried samples was used to determine DNA ploidy level in 5033 individuals from 100 populations spread over the entire Eastern Alpine distribution area of S. carniolicus. Descriptors of microhabitats as well as spatial data were recorded in the field, and analysed with a mixed-effects ANOVA. KEY RESULTS Extensive variation in DNA ploidy levels (2x, 3x, 4x, 5x, 6x, 7x, 8x, 9x) was detected. Of the main cytotypes, diploids and hexaploids were widespread and had strongly overlapping distributions resulting in the frequent occurrence of cytotype mixtures (half of the investigated populations), whereas tetraploids were disjunctly distributed and occurred in the south-west and the east of the species' distribution area. In spite of the frequent co-occurrence of cytotypes, only 1 % of the samples belonged to secondary cytotypes (3x, 5x, 7x, 8x, 9x). Diploids, tetraploids and hexaploids were altitudinally segregated, but with broad overlap. Similarly, highly significant differences in vegetation and rock cover as well as microhabitat exposure were found between the main cytotypes. CONCLUSIONS Senecio carniolicus shows a remarkable diversity of cytotypes. The distribution of the three main cytotypes (2x, 4x, 6x) has been shaped by Pleistocene glaciations to different extents. Whereas tetraploids are nearly entirely restricted to refugia, hexaploids colonized areas that were extensively glaciated. Diploid and hexaploid individuals often co-occur in mixed populations, where they are spatially and ecologically segregated at both the meso-scale (altitudinal differentiation, exposure of the growing site) and the micro-scale (cover of vegetation and bare rock). With regard to the ecological parameters investigated, the tetraploid cytotype occupies an intermediate position. The rareness of secondary cytotypes suggests the presence of strong pre- or post-zygotic mating barriers.
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Affiliation(s)
- Michaela Sonnleitner
- Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, Vienna 1030, Austria
| | - Ruth Flatscher
- Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, Vienna 1030, Austria
| | - Pedro Escobar García
- Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, Vienna 1030, Austria
| | - Jana Rauchová
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, CZ-252 43, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01, Czech Republic
| | - Jan Suda
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, CZ-252 43, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01, Czech Republic
| | - Gerald M. Schneeweiss
- Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, Vienna 1030, Austria
- Systematic Botany and Mycology, Ludwig-Maximilians-University Munich, Menzingerstrasse 61, D-80638 Munich, Germany
| | - Karl Hülber
- Vienna Institute for Nature Conservation & Analyses, Giessergasse 6/7, Vienna 1090, Austria
- Department of Conservation Biology, Vegetation Ecology and Landscape Ecology, University of Vienna, Rennweg 14, Vienna 1030, Austria
| | - Peter Schönswetter
- Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, Vienna 1030, Austria
- Department of Systematics, Palynology and Geobotany, Institute of Botany, University of Innsbruck, Sternwartestrasse 15, 6020 Innsbruck, Austria
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137
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Henriques R, Magyar Z, Monardes A, Khan S, Zalejski C, Orellana J, Szabados L, de la Torre C, Koncz C, Bögre L. Arabidopsis S6 kinase mutants display chromosome instability and altered RBR1-E2F pathway activity. EMBO J 2010; 29:2979-93. [PMID: 20683442 DOI: 10.1038/emboj.2010.164] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Accepted: 06/29/2010] [Indexed: 12/27/2022] Open
Abstract
The 40S ribosomal protein S6 kinase (S6K) is a conserved component of signalling pathways controlling growth in eukaryotes. To study S6K function in plants, we isolated single- and double-knockout mutations and RNA-interference (RNAi)-silencing lines in the linked Arabidopsis S6K1 and S6K2 genes. Hemizygous s6k1s6k2/++ mutant and S6K1 RNAi lines show high phenotypic instability with variation in size, increased trichome branching, produce non-viable pollen and high levels of aborted seeds. Analysis of their DNA content by flow cytometry, as well as chromosome counting using DAPI staining and fluorescence in situ hybridization, revealed an increase in ploidy and aneuploidy. In agreement with this data, we found that S6K1 associates with the Retinoblastoma-related 1 (RBR1)-E2FB complex and this is partly mediated by its N-terminal LVxCxE motif. Moreover, the S6K1-RBR1 association regulates RBR1 nuclear localization, as well as E2F-dependent expression of cell cycle genes. Arabidopsis cells grown under nutrient-limiting conditions require S6K for repression of cell proliferation. The data suggest a new function for plant S6K as a repressor of cell proliferation and required for maintenance of chromosome stability and ploidy levels.
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Affiliation(s)
- Rossana Henriques
- Royal Holloway, University of London, School of Biological Sciences, Egham Hill, Egham, UK.
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138
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Chester M, Leitch AR, Soltis PS, Soltis DE. Review of the Application of Modern Cytogenetic Methods (FISH/GISH) to the Study of Reticulation (Polyploidy/Hybridisation). Genes (Basel) 2010; 1. [PMID: 24710040 PMCID: PMC3954085 DOI: 10.3390/genes1010166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The convergence of distinct lineages upon interspecific hybridisation, including when accompanied by increases in ploidy (allopolyploidy), is a driving force in the origin of many plant species. In plant breeding too, both interspecific hybridisation and allopolyploidy are important because they facilitate introgression of alien DNA into breeding lines enabling the introduction of novel characters. Here we review how fluorescence in situ hybridisation (FISH) and genomic in situ hybridisation (GISH) have been applied to: 1) studies of interspecific hybridisation and polyploidy in nature, 2) analyses of phylogenetic relationships between species, 3) genetic mapping and 4) analysis of plant breeding materials. We also review how FISH is poised to take advantage of nextgeneration sequencing (NGS) technologies, helping the rapid characterisation of the repetitive fractions of a genome in natural populations and agricultural plants.
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Affiliation(s)
- Michael Chester
- Department of Biology, University of Florida, Gainesville, Florida 32611, USA.
| | - Andrew R Leitch
- School of Biological and Chemical Sciences, Queen Mary, University of London, UK.
| | - Pamela S Soltis
- Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611, USA.
| | - Douglas E Soltis
- Department of Biology, University of Florida, Gainesville, Florida 32611, USA.
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139
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Chester M, Leitch AR, Soltis PS, Soltis DE. Review of the Application of Modern Cytogenetic Methods (FISH/GISH) to the Study of Reticulation (Polyploidy/Hybridisation). Genes (Basel) 2010; 1:166-92. [PMID: 24710040 PMCID: PMC3954085 DOI: 10.3390/genes1020166] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 06/30/2010] [Accepted: 06/30/2010] [Indexed: 11/16/2022] Open
Abstract
The convergence of distinct lineages upon interspecific hybridisation, including when accompanied by increases in ploidy (allopolyploidy), is a driving force in the origin of many plant species. In plant breeding too, both interspecific hybridisation and allopolyploidy are important because they facilitate introgression of alien DNA into breeding lines enabling the introduction of novel characters. Here we review how fluorescence in situ hybridisation (FISH) and genomic in situ hybridisation (GISH) have been applied to: 1) studies of interspecific hybridisation and polyploidy in nature, 2) analyses of phylogenetic relationships between species, 3) genetic mapping and 4) analysis of plant breeding materials. We also review how FISH is poised to take advantage of nextgeneration sequencing (NGS) technologies, helping the rapid characterisation of the repetitive fractions of a genome in natural populations and agricultural plants.
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Affiliation(s)
- Michael Chester
- Department of Biology, University of Florida, Gainesville, Florida 32611, USA.
| | - Andrew R Leitch
- School of Biological and Chemical Sciences, Queen Mary, University of London, UK.
| | - Pamela S Soltis
- Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611, USA.
| | - Douglas E Soltis
- Department of Biology, University of Florida, Gainesville, Florida 32611, USA.
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