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Ambrose BA, Stevenson DW. The evolution and development of sporangia-The fundamental reproductive organ of land plant sporophytes. CURRENT OPINION IN PLANT BIOLOGY 2024; 81:102563. [PMID: 38838582 DOI: 10.1016/j.pbi.2024.102563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 04/22/2024] [Accepted: 05/10/2024] [Indexed: 06/07/2024]
Abstract
A key innovation of land plants is the origin and evolution of the sporangium, the fundamental reproductive structure of the diploid sporophyte. In vascular plants, whether the structure is a cone, fertile leaf, or flower-all are clusters of sporangia. The evolution of morphologically distinct sporangia (heterospory) and retention of the gametophyte evolved three times independently as a prerequisite for the evolution of seeds. This review summarizes the development of vascular plant sporangia, molecular genetics of angiosperm sporangia, and provides a framework to investigate evolution and development in vascular plant sporangia.
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Affiliation(s)
- Barbara A Ambrose
- The New York Botanical Garden, 2900 Southern Blvd., Bronx, NY, 10458, USA.
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2
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Siena LA, Michaud C, Selles B, Vega JM, Pessino SC, Ingouff M, Ortiz JPA, Leblanc O. TRIMETHYLGUANOSINE SYNTHASE1 mutations decanalize female germline development in Arabidopsis. THE NEW PHYTOLOGIST 2023; 240:597-612. [PMID: 37548040 DOI: 10.1111/nph.19179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 07/14/2023] [Indexed: 08/08/2023]
Abstract
Here, we report the characterization of a plant RNA methyltransferase, orthologous to yeast trimethylguanosine synthase1 (Tgs1p) and whose downregulation was associated with apomixis in Paspalum grasses. Using phylogenetic analyses and yeast complementation, we determined that land plant genomes all encode a conserved, specific TGS1 protein. Next, we studied the role of TGS1 in female reproduction using reporter lines and loss-of-function mutants in Arabidopsis thaliana. pAtTGS1:AtTGS1 reporters showed a dynamic expression pattern. They were highly active in the placenta and ovule primordia at emergence but, subsequently, showed weak signals in the nucellus. Although expressed throughout gametophyte development, activity became restricted to the female gamete and was also detected after fertilization during embryogenesis. TGS1 depletion altered the specification of the precursor cells that give rise to the female gametophytic generation and to the sporophyte, resulting in the formation of a functional aposporous-like lineage. Our results indicate that TGS1 participates in the mechanisms restricting cell fate acquisition to a single cell at critical transitions throughout the female reproductive lineage and, thus, expand our current knowledge of the mechanisms governing female reproductive fate in plants.
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Affiliation(s)
- Lorena A Siena
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | | | - Benjamin Selles
- DIADE, Univ Montpellier, IRD, CIRAD, 34394, Montpellier, France
| | - Juan Manuel Vega
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Silvina C Pessino
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Mathieu Ingouff
- DIADE, Univ Montpellier, IRD, CIRAD, 34394, Montpellier, France
| | - Juan Pablo A Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Olivier Leblanc
- DIADE, Univ Montpellier, IRD, CIRAD, 34394, Montpellier, France
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Zhu M, Tao L, Zhang J, Liu R, Tian H, Hu C, Zhu Y, Li M, Wei Z, Yi J, Li J, Gou X. The type-B response regulators ARR10, ARR12, and ARR18 specify the central cell in Arabidopsis. THE PLANT CELL 2022; 34:4714-4737. [PMID: 36130292 PMCID: PMC9709988 DOI: 10.1093/plcell/koac285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/15/2022] [Indexed: 06/15/2023]
Abstract
In Arabidopsis thaliana, the female gametophyte consists of two synergid cells, an egg cell, a diploid central cell, and three antipodal cells. CYTOKININ INDEPENDENT 1 (CKI1), a histidine kinase constitutively activating the cytokinin signaling pathway, specifies the central cell and restricts the egg cell. However, the mechanism regulating CKI1-dependent central cell specification is largely unknown. Here, we showed that the type-B ARABIDOPSIS RESPONSE REGULATORS10, 12, and 18 (ARR10/12/18) localize at the chalazal pole of the female gametophyte. Phenotypic analysis showed that the arr10 12 18 triple mutant is female sterile. We examined the expression patterns of embryo sac marker genes and found that the embryo sac of arr10 12 18 plants had lost central cell identity, a phenotype similar to that of the Arabidopsis cki1 mutant. Genetic analyses demonstrated that ARR10/12/18, CKI1, and ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN2, 3, and 5 (AHP2/3/5) function in a common pathway to regulate female gametophyte development. In addition, constitutively activated ARR10/12/18 in the cki1 embryo sac partially restored the fertility of cki1. Results of transcriptomic analysis supported the conclusion that ARR10/12/18 and CKI1 function together to regulate the identity of the central cell. Our results demonstrated that ARR10/12/18 function downstream of CKI1-AHP2/3/5 as core factors to determine cell fate of the female gametophyte.
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Affiliation(s)
- Mingsong Zhu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Liang Tao
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jinghua Zhang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Ruini Liu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Hongai Tian
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Chong Hu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yafen Zhu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Meizhen Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Zhuoyun Wei
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jing Yi
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jia Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Xiaoping Gou
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
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Zhang J, Pai Q, Yue L, Wu X, Liu H, Wang W. Cytokinin regulates female gametophyte development by cell cycle modulation in Arabidopsis thaliana. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 324:111419. [PMID: 35995110 DOI: 10.1016/j.plantsci.2022.111419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 06/15/2023]
Abstract
Male and female gametophyte development, double fertilization, and embryogenesis are key to alternating generations in angiosperms. The female gametophyte of Arabidopsis is an eight-nucleate haploid structure developed from functional megaspores (FMs) through three flawless mitoses regulated by a series of cell cycle genes. Cytokinin, an important phytohormone, plays a critical role in the regulation of plant growth and development. However, the mechanisms by which cytokinins regulate female gametophyte development remain largely unknown. In this study, we constructed transgenic plants (pES1::CKX1) with low cytokinin levels in the embryo sac. Phenotypic analysis showed that pES1::CKX1 inhibits female gametophyte development. Microscopic observation revealed that female gametophyte development of pES1::CKX1 was delayed. The promoters of all cell cycle genes were cloned and transformed into wild-type (WT). We crossed these transgenic plants of cell cycle genes expressed in ovules with pES1::CKX1 and compared the expression level of β-glucuronidase (GUS) in pES1::CKX1 and WT. Many cell cycle-regulated genes were up or downregulated in pES1::CKX1 compared with WT, and the embryo sac development cell cycle in cycd2;1/+ cycd3;3 was defective. Our results demonstrated that cytokinin affects cell division in the female gametophyte by affecting the expression of cell cycle genes.
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Affiliation(s)
- Jinghua Zhang
- National Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China
| | - Qiaofeng Pai
- National Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China
| | - Ling Yue
- National Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China
| | - Xiaolin Wu
- National Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China
| | - Hui Liu
- National Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China.
| | - Wei Wang
- National Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China.
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Stein RE, Nauerth BH, Binmöller L, Zühl L, Loreth A, Reinert M, Ibberson D, Schmidt A. RH17 restricts reproductive fate and represses autonomous seed coat development in sexual Arabidopsis. Development 2021; 148:272091. [PMID: 34495331 DOI: 10.1242/dev.198739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 08/31/2021] [Indexed: 12/13/2022]
Abstract
Plant sexual and asexual reproduction through seeds (apomixis) is tightly controlled by complex gene regulatory programs, which are not yet fully understood. Recent findings suggest that RNA helicases are required for plant germline development. This resembles their crucial roles in animals, where they are involved in controlling gene activity and the maintenance of genome integrity. Here, we identified previously unknown roles of Arabidopsis RH17 during reproductive development. Interestingly, RH17 is involved in repression of reproductive fate and of elements of seed development in the absence of fertilization. In lines carrying a mutant rh17 allele, development of supernumerary reproductive cell lineages in the female flower tissues (ovules) was observed, occasionally leading to formation of two embryos per seed. Furthermore, seed coat, and putatively also endosperm development, frequently initiated autonomously. Such induction of several features phenocopying distinct elements of apomixis by a single mutation is unusual and suggests that RH17 acts in regulatory control of plant reproductive development. Furthermore, an in-depth understanding of its action might be of use for agricultural applications.
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Affiliation(s)
- Ron Eric Stein
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Berit Helge Nauerth
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Laura Binmöller
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Luise Zühl
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Anna Loreth
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Maximilian Reinert
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - David Ibberson
- Deep Sequencing Core Facility, CellNetworks Excellence Cluster, Heidelberg University, Im Neuenheimer Feld 267, D-69120, Heidelberg, Germany
| | - Anja Schmidt
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
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Mao B, Zheng W, Huang Z, Peng Y, Shao Y, Liu C, Tang L, Hu Y, Li Y, Hu L, Zhang D, Yuan Z, Luo W, Yuan L, Liu Y, Zhao B. Rice MutLγ, the MLH1-MLH3 heterodimer, participates in the formation of type I crossovers and regulation of embryo sac fertility. PLANT BIOTECHNOLOGY JOURNAL 2021; 19:1443-1455. [PMID: 33544956 PMCID: PMC8313138 DOI: 10.1111/pbi.13563] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/19/2021] [Accepted: 01/25/2021] [Indexed: 05/23/2023]
Abstract
The development of embryo sacs is crucial for seed production in plants, but the genetic basis regulating the meiotic crossover formation in the macrospore and microspore mother cells remains largely unclear. Here, we report the characterization of a spontaneous rice female sterile variation 1 mutant (fsv1) that showed severe embryo sacs abortion with low seed-setting rate. Through map-based cloning and functional analyses, we isolated the causal gene of fsv1, OsMLH3 encoding a MutL-homolog 3 protein, an ortholog of HvMLH3 in barley and AtMLH3 in Arabidopsis. OsMLH3 and OsMLH1 (MutL-homolog 1) interact to form a heterodimer (MutLγ) to promote crossover formation in the macrospore and microspore mother cells and development of functional megaspore during meiosis, defective OsMLH3 or OsMLH1 in fsv1 and CRISPR/Cas9-based knockout lines results in reduced type I crossover and bivalent frequency. The fsv1 and OsMLH3-knockout lines are valuable germplasms for development of female sterile restorer lines for mechanized seed production of hybrid rice.
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Affiliation(s)
- Bigang Mao
- State Key Laboratory of Hybrid RiceHunan Hybrid Rice Research CenterChangshaChina
- Long Ping BranchGraduate School of Hunan UniversityChangshaChina
| | - Wenjie Zheng
- Long Ping BranchGraduate School of Hunan UniversityChangshaChina
| | - Zhen Huang
- State Key Laboratory of Hybrid RiceHunan Hybrid Rice Research CenterChangshaChina
| | - Yan Peng
- State Key Laboratory of Hybrid RiceHunan Hybrid Rice Research CenterChangshaChina
| | - Ye Shao
- State Key Laboratory of Hybrid RiceHunan Hybrid Rice Research CenterChangshaChina
| | - Citao Liu
- College of AgriculturalHunan Agricultural UniversityChangshaChina
| | - Li Tang
- State Key Laboratory of Hybrid RiceHunan Hybrid Rice Research CenterChangshaChina
- Long Ping BranchGraduate School of Hunan UniversityChangshaChina
| | - Yuanyi Hu
- State Key Laboratory of Hybrid RiceHunan Hybrid Rice Research CenterChangshaChina
| | - Yaokui Li
- State Key Laboratory of Hybrid RiceHunan Hybrid Rice Research CenterChangshaChina
| | - Liming Hu
- Long Ping BranchGraduate School of Hunan UniversityChangshaChina
| | - Dan Zhang
- State Key Laboratory of Hybrid RiceHunan Hybrid Rice Research CenterChangshaChina
| | - Zhicheng Yuan
- State Key Laboratory of Hybrid RiceHunan Hybrid Rice Research CenterChangshaChina
| | - Wuzhong Luo
- State Key Laboratory of Hybrid RiceHunan Hybrid Rice Research CenterChangshaChina
| | - Longping Yuan
- State Key Laboratory of Hybrid RiceHunan Hybrid Rice Research CenterChangshaChina
| | - Yaoguang Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesSouth China Agricultural UniversityGuangzhouChina
| | - Bingran Zhao
- State Key Laboratory of Hybrid RiceHunan Hybrid Rice Research CenterChangshaChina
- Long Ping BranchGraduate School of Hunan UniversityChangshaChina
- College of AgriculturalHunan Agricultural UniversityChangshaChina
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7
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Proceedings of the 7th Series of Seminars on Advances in Apomixis Research. PLANTS 2021; 10:plants10030565. [PMID: 33802754 PMCID: PMC8002402 DOI: 10.3390/plants10030565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 03/14/2021] [Accepted: 03/15/2021] [Indexed: 11/17/2022]
Abstract
These proceedings contain the abstracts for the presentations given at the 7th biennial Seminars on Advances in Apomixis Research, held virtually on 2-3 and 9 December 2020. The first day hosted the kick-off meeting of the EU-funded Mechanisms of Apomictic Development (MAD) project, while the remaining days were dedicated to oral presentations and in-depth exchanges on the latest progress in the field of apomixis and plant reproductive biology research.
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Vijayan A, Tofanelli R, Strauss S, Cerrone L, Wolny A, Strohmeier J, Kreshuk A, Hamprecht FA, Smith RS, Schneitz K. A digital 3D reference atlas reveals cellular growth patterns shaping the Arabidopsis ovule. eLife 2021; 10:e63262. [PMID: 33404501 PMCID: PMC7787667 DOI: 10.7554/elife.63262] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 12/19/2020] [Indexed: 12/23/2022] Open
Abstract
A fundamental question in biology is how morphogenesis integrates the multitude of processes that act at different scales, ranging from the molecular control of gene expression to cellular coordination in a tissue. Using machine-learning-based digital image analysis, we generated a three-dimensional atlas of ovule development in Arabidopsis thaliana, enabling the quantitative spatio-temporal analysis of cellular and gene expression patterns with cell and tissue resolution. We discovered novel morphological manifestations of ovule polarity, a new mode of cell layer formation, and previously unrecognized subepidermal cell populations that initiate ovule curvature. The data suggest an irregular cellular build-up of WUSCHEL expression in the primordium and new functions for INNER NO OUTER in restricting nucellar cell proliferation and the organization of the interior chalaza. Our work demonstrates the analytical power of a three-dimensional digital representation when studying the morphogenesis of an organ of complex architecture that eventually consists of 1900 cells.
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Affiliation(s)
- Athul Vijayan
- Plant Developmental Biology, School of Life Sciences, Technical University of MunichFreisingGermany
| | - Rachele Tofanelli
- Plant Developmental Biology, School of Life Sciences, Technical University of MunichFreisingGermany
| | - Sören Strauss
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding ResearchCologneGermany
| | - Lorenzo Cerrone
- Heidelberg Collaboratory for Image Processing, Dept. of Physics and Astronomy, Heidelberg UniversityHeidelbergGermany
| | - Adrian Wolny
- Heidelberg Collaboratory for Image Processing, Dept. of Physics and Astronomy, Heidelberg UniversityHeidelbergGermany
- European Molecular Biology LaboratoryHeidelbergGermany
| | - Joanna Strohmeier
- Plant Developmental Biology, School of Life Sciences, Technical University of MunichFreisingGermany
| | - Anna Kreshuk
- European Molecular Biology LaboratoryHeidelbergGermany
| | - Fred A Hamprecht
- Heidelberg Collaboratory for Image Processing, Dept. of Physics and Astronomy, Heidelberg UniversityHeidelbergGermany
| | - Richard S Smith
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding ResearchCologneGermany
| | - Kay Schneitz
- Plant Developmental Biology, School of Life Sciences, Technical University of MunichFreisingGermany
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Kiefer M, Nauerth BH, Volkert C, Ibberson D, Loreth A, Schmidt A. Gene Function Rather than Reproductive Mode Drives the Evolution of RNA Helicases in Sexual and Apomictic Boechera. Genome Biol Evol 2020; 12:656-673. [PMID: 32302391 PMCID: PMC7250504 DOI: 10.1093/gbe/evaa078] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2020] [Indexed: 12/20/2022] Open
Abstract
In higher plants, sexual and asexual reproductions through seeds (apomixis) have evolved as alternative strategies. Evolutionary advantages leading to coexistence of both reproductive modes are currently not well understood. It is expected that accumulation of deleterious mutations leads to a rapid elimination of apomictic lineages from populations. In this line, apomixis originated repeatedly, likely from deregulation of the sexual pathway, leading to alterations in the development of reproductive lineages (germlines) in apomicts as compared with sexual plants. This potentially involves mutations in genes controlling reproduction. Increasing evidence suggests that RNA helicases are crucial regulators of germline development. To gain insights into the evolution of 58 members of this diverse gene family in sexual and apomictic plants, we applied target enrichment combined with next-generation sequencing to identify allelic variants from 24 accessions of the genus Boechera, comprising sexual, facultative, and obligate apomicts. Interestingly, allelic variants from apomicts did not show consistently increased mutation frequency. Either sequences were highly conserved in any accession, or allelic variants preferentially harbored mutations in evolutionary less conserved C- and N-terminal domains, or presented high mutation load independent of the reproductive mode. Only for a few genes allelic variants harboring deleterious mutations were only identified in apomicts. To test if high sequence conservation correlates with roles in fundamental cellular or developmental processes, we analyzed Arabidopsis thaliana mutant lines in VASA-LIKE (VASL), and identified pleiotropic defects during ovule and reproductive development. This indicates that also in apomicts mechanisms of selection are in place based on gene function.
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Affiliation(s)
- Markus Kiefer
- Department of Biodiversity and Plant Systematics, Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Berit H Nauerth
- Department of Biodiversity and Plant Systematics, Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Christopher Volkert
- Department of Biodiversity and Plant Systematics, Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - David Ibberson
- Deep Sequencing Core Facility, CellNetworks Excellence Cluster, Heidelberg University, Heidelberg, Germany
| | - Anna Loreth
- Department of Biodiversity and Plant Systematics, Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Anja Schmidt
- Department of Biodiversity and Plant Systematics, Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
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Hater F, Nakel T, Groß-Hardt R. Reproductive Multitasking: The Female Gametophyte. ANNUAL REVIEW OF PLANT BIOLOGY 2020; 71:517-546. [PMID: 32442389 DOI: 10.1146/annurev-arplant-081519-035943] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Fertilization of flowering plants requires the organization of complex tasks, many of which become integrated by the female gametophyte (FG). The FG is a few-celled haploid structure that orchestrates division of labor to coordinate successful interaction with the sperm cells and their transport vehicle, the pollen tube. As reproductive outcome is directly coupled to evolutionary success, the underlying mechanisms are under robust molecular control, including integrity check and repair mechanisms. Here, we review progress on understanding the development and function of the FG, starting with the functional megaspore, which represents the haploid founder cell of the FG. We highlight recent achievements that have greatly advanced our understanding of pollen tube attraction strategies and the mechanisms that regulate plant hybridization and gamete fusion. In addition, we discuss novel insights into plant polyploidization strategies that expand current concepts on the evolution of flowering plants.
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Affiliation(s)
- Friederike Hater
- Centre for Biomolecular Interactions, University of Bremen, 28359 Bremen, Germany;
| | - Thomas Nakel
- Centre for Biomolecular Interactions, University of Bremen, 28359 Bremen, Germany;
| | - Rita Groß-Hardt
- Centre for Biomolecular Interactions, University of Bremen, 28359 Bremen, Germany;
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11
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Controlling Apomixis: Shared Features and Distinct Characteristics of Gene Regulation. Genes (Basel) 2020; 11:genes11030329. [PMID: 32245021 PMCID: PMC7140868 DOI: 10.3390/genes11030329] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 02/06/2023] Open
Abstract
In higher plants, sexual and asexual reproduction through seeds (apomixis) have evolved as alternative strategies. As apomixis leads to the formation of clonal offspring, its great potential for agricultural applications has long been recognized. However, the genetic basis and the molecular control underlying apomixis and its evolutionary origin are to date not fully understood. Both in sexual and apomictic plants, reproduction is tightly controlled by versatile mechanisms regulating gene expression, translation, and protein abundance and activity. Increasing evidence suggests that interrelated pathways including epigenetic regulation, cell-cycle control, hormonal pathways, and signal transduction processes are relevant for apomixis. Additional molecular mechanisms are being identified that involve the activity of DNA- and RNA-binding proteins, such as RNA helicases which are increasingly recognized as important regulators of reproduction. Together with other factors including non-coding RNAs, their association with ribosomes is likely to be relevant for the formation and specification of the apomictic reproductive lineage. Subsequent seed formation appears to involve an interplay of transcriptional activation and repression of developmental programs by epigenetic regulatory mechanisms. In this review, insights into the genetic basis and molecular control of apomixis are presented, also taking into account potential relations to environmental stress, and considering aspects of evolution.
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12
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Zühl L, Volkert C, Ibberson D, Schmidt A. Differential activity of F-box genes and E3 ligases distinguishes sexual versus apomictic germline specification in Boechera. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5643-5657. [PMID: 31294816 PMCID: PMC6812705 DOI: 10.1093/jxb/erz323] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 07/01/2019] [Indexed: 05/22/2023]
Abstract
Germline specification is the first step during sexual and apomictic plant reproduction, and takes place in the nucellus of the ovule, a specialized domain of the reproductive flower tissues. In each case, a sporophytic cell is determined to form the sexual megaspore mother cell (MMC) or an apomictic initial cell (AIC). These differ in their developmental fates: while the MMC undergoes meiosis, the AIC modifies or omits meiosis to form the female gametophyte. Despite great interest in these distinct developmental processes, little is known about their gene regulatory basis. To elucidate the gene regulatory networks underlying germline specification, we conducted tissue-specific transcriptional profiling using laser-assisted microdissection and RNA sequencing to compare the transcriptomes of nucellar tissues between different sexual and apomictic Boechera accessions representing four species and two ploidy levels. This allowed us to distinguish between expression differences caused by genetic background or reproductive mode. Statistical data analysis revealed 45 genes that were significantly differentially expressed, and which potentially play a role for determination of the reproductive mode. Based on annotations, these included F-box genes and E3 ligases that most likely relate to genes previously described as regulators important for germline development. Our findings provide novel insights into the transcriptional basis of sexual and apomictic reproduction.
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Affiliation(s)
- Luise Zühl
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld, Heidelberg
- Present address: Max Planck Institute for Plant Breeding Research, Department of Comparative Development and Genetics, Carl-von-Linné-Weg 10, D-50829 Cologne
| | - Christopher Volkert
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld, Heidelberg
| | - David Ibberson
- Deep Sequencing Core Facility, CellNetworks Excellence Cluster, Heidelberg University, Im Neuenheimer Feld, Heidelberg
| | - Anja Schmidt
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld, Heidelberg
- Correspondence:
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Advances Towards How Meiotic Recombination Is Initiated: A Comparative View and Perspectives for Plant Meiosis Research. Int J Mol Sci 2019; 20:ijms20194718. [PMID: 31547623 PMCID: PMC6801837 DOI: 10.3390/ijms20194718] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 09/19/2019] [Accepted: 09/19/2019] [Indexed: 12/14/2022] Open
Abstract
Meiosis is an essential cell-division process for ensuring genetic diversity across generations. Meiotic recombination ensures the accuracy of genetic interchange between homolous chromosomes and segregation of parental alleles. Programmed DNA double-strand breaks (DSBs), catalyzed by the evolutionarily conserved topoisomerase VIA (a subunit of the archaeal type II DNA topoisomerase)-like enzyme Spo11 and several other factors, is a distinctive feature of meiotic recombination initiation. The meiotic DSB formation and its regulatory mechanisms are similar among species, but certain aspects are distinct. In this review, we introduced the cumulative knowledge of the plant proteins crucial for meiotic DSB formation and technical advances in DSB detection. We also summarized the genome-wide DSB hotspot profiles for different model organisms. Moreover, we highlighted the classical views and recent advances in our knowledge of the regulatory mechanisms that ensure the fidelity of DSB formation, such as multifaceted kinase-mediated phosphorylation and the consequent high-dimensional changes in chromosome structure. We provided an overview of recent findings concerning DSB formation, distribution and regulation, all of which will help us to determine whether meiotic DSB formation is evolutionarily conserved or varies between plants and other organisms.
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Hisanaga T, Okahashi K, Yamaoka S, Kajiwara T, Nishihama R, Shimamura M, Yamato KT, Bowman JL, Kohchi T, Nakajima K. A cis-acting bidirectional transcription switch controls sexual dimorphism in the liverwort. EMBO J 2019; 38:embj.2018100240. [PMID: 30609993 PMCID: PMC6418429 DOI: 10.15252/embj.2018100240] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 11/17/2018] [Accepted: 11/27/2018] [Indexed: 01/19/2023] Open
Abstract
Plant life cycles alternate between haploid gametophytes and diploid sporophytes. While regulatory factors determining male and female sexual morphologies have been identified for sporophytic reproductive organs, such as stamens and pistils of angiosperms, those regulating sex‐specific traits in the haploid gametophytes that produce male and female gametes and hence are central to plant sexual reproduction are poorly understood. Here, we identified a MYB‐type transcription factor, MpFGMYB, as a key regulator of female sexual differentiation in the haploid‐dominant dioicous liverwort, Marchantia polymorpha. MpFGMYB is specifically expressed in females and its loss resulted in female‐to‐male sex conversion. Strikingly, MpFGMYB expression is suppressed in males by a cis‐acting antisense gene SUF at the same locus, and loss‐of‐function suf mutations resulted in male‐to‐female sex conversion. Thus, the bidirectional transcription module at the MpFGMYB/SUF locus acts as a toggle between female and male sexual differentiation in M. polymorpha gametophytes. Arabidopsis thaliana MpFGMYB orthologs are known to be expressed in embryo sacs and promote their development. Thus, phylogenetically related MYB transcription factors regulate female gametophyte development across land plants.
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Affiliation(s)
- Tetsuya Hisanaga
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | | | - Shohei Yamaoka
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | | | | | - Masaki Shimamura
- Graduate School of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Japan
| | - Katsuyuki T Yamato
- Faculty of Biology-Oriented Science and Technology, Kindai University, Kinokawa, Wakayama, Japan
| | - John L Bowman
- School of Biological Sciences, Monash University, Melbourne, Vic., Australia
| | - Takayuki Kohchi
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Keiji Nakajima
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
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Tofanelli R, Vijayan A, Scholz S, Schneitz K. Protocol for rapid clearing and staining of fixed Arabidopsis ovules for improved imaging by confocal laser scanning microscopy. PLANT METHODS 2019; 15:120. [PMID: 31673277 PMCID: PMC6814113 DOI: 10.1186/s13007-019-0505-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 10/17/2019] [Indexed: 05/15/2023]
Abstract
BACKGROUND A salient topic in developmental biology relates to the molecular and genetic mechanisms that underlie tissue morphogenesis. Modern quantitative approaches to this central question frequently involve digital cellular models of the organ or tissue under study. The ovules of the model species Arabidopsis thaliana have long been established as a model system for the study of organogenesis in plants. While ovule development in Arabidopsis can be followed by a variety of different imaging techniques, no experimental strategy presently exists that enables an easy and straightforward investigation of the morphology of internal tissues of the ovule with cellular resolution. RESULTS We developed a protocol for rapid and robust confocal microscopy of fixed Arabidopsis ovules of all stages. The method combines clearing of fixed ovules in ClearSee solution with marking the cell outline using the cell wall stain SCRI Renaissance 2200 and the nuclei with the stain TO-PRO-3 iodide. We further improved the microscopy by employing a homogenous immersion system aimed at minimizing refractive index differences. The method allows complete inspection of the cellular architecture even deep within the ovule. Using the new protocol we were able to generate digital three-dimensional models of ovules of various stages. CONCLUSIONS The protocol enables the quick and reproducible imaging of fixed Arabidopsis ovules of all developmental stages. From the imaging data three-dimensional digital ovule models with cellular resolution can be rapidly generated using image analysis software, for example MorphographX. Such digital models will provide the foundation for a future quantitative analysis of ovule morphogenesis in a model species.
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Affiliation(s)
- Rachele Tofanelli
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Athul Vijayan
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Sebastian Scholz
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
- Present Address: EU Research Lab, Technische Hochschule Wildau, 15745 Wildau, Germany
| | - Kay Schneitz
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
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León-Martínez G, Vielle-Calzada JP. Apomixis in flowering plants: Developmental and evolutionary considerations. Curr Top Dev Biol 2019; 131:565-604. [DOI: 10.1016/bs.ctdb.2018.11.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Erbasol Serbes I, Palovaara J, Groß-Hardt R. Development and function of the flowering plant female gametophyte. Curr Top Dev Biol 2019; 131:401-434. [DOI: 10.1016/bs.ctdb.2018.11.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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