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Wang T, Li Y, Song S, Qiu M, Zhang L, Li C, Dong H, Li L, Wang J, Li L. EMBRYO SAC DEVELOPMENT 1 affects seed setting rate in rice by controlling embryo sac development. Plant Physiol 2021; 186:1060-1073. [PMID: 33734397 PMCID: PMC8195536 DOI: 10.1093/plphys/kiab106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 02/11/2021] [Indexed: 05/16/2023]
Abstract
Seed setting rate is one of the critical factors that determine rice yield. Grain formation is a complex biological process, whose molecular mechanism is yet to be improved. Here we investigated the function of an OVATE family protein, Embryo Sac Development 1 (ESD1), in the regulation of seed setting rate in rice (Oryza sativa) by examining its loss-of-function mutants generated via clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated9 (Cas9) technology. ESD1 was predominantly expressed at Stage 6 of panicle development, especially in the ovules. esd1 mutants displayed reduced seed setting rates with normal stamen development and pollen tube growth but abnormal pistil group. Investigation of embryo sacs revealed that during the mitosis of functional megaspores, some egg cells degraded during differentiation in esd1 mutants, thereby hindering subsequent fertilization process and reducing seed setting rate. In addition, the transcriptional level of O. sativa anaphase-promoting complex 6, a reported embryo sac developing gene, was significantly reduced in esd1 mutants. These results support that ESD1 is an important modulator of ESD and seed setting rate in rice. Together, this finding demonstrates that ESD1 positively regulates the seed setting rate by controlling ESD in rice and has implications for the improvement of rice yield.
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Affiliation(s)
- Tiankang Wang
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha 410125, China
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China
| | - Yixing Li
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha 410125, China
| | - Shufeng Song
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha 410125, China
| | - Mudan Qiu
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha 410125, China
| | - Licheng Zhang
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China
| | - Chengxia Li
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha 410125, China
| | - Hao Dong
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha 410125, China
| | - Lei Li
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China
| | - Jianlong Wang
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China
| | - Li Li
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China
- Author for communication:
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Losada JM, Herrero M. Arabinogalactan proteins mediate intercellular crosstalk in the ovule of apple flowers. Plant Reprod 2019; 32:291-305. [PMID: 31049682 DOI: 10.1007/s00497-019-00370-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 04/23/2019] [Indexed: 05/29/2023]
Abstract
AGP-rich glycoproteins mediate pollen-ovule interactions and cell patterning in the embryo sac of apple before and after fertilization. Glycoproteins are significant players in the dialog that takes place between growing pollen tubes and the stigma and style in the angiosperms. Yet, information is scarce on their possible involvement in the ovule, a sporophytic organ that hosts the female gametophyte. Apple flowers have a prolonged lapse of time between pollination and fertilization, offering a great system to study the developmental basis of glycoprotein secretion and their putative role during the last stages of the progamic phase and early seed initiation. For this purpose, the sequential pollen tube elongation within the ovary was examined in relation to changes in arabinogalactan proteins (AGPs) in the tissues of the ovule before and after fertilization. To evaluate what of these changes are developmentally regulated, unpollinated and pollinated flowers were compared. AGPs paved the pollen tube pathway in the ovules along the micropylar canal, and the nucellus entrance toward the synergids, which also developmentally accumulated AGPs at the filiform apparatus. Glycoproteins vanished from all these tissues following pollen tube passage, strongly suggesting a role in pollen-ovule interaction. In addition, AGPs marked the primary cell walls of the haploid cells of the female gametophyte, and they further built up in the cell walls of the embryo sac and developing embryo, layering the interactive walls of the three generations hosted in the ovule, the maternal sporophytic tissues, the female gametophyte, and the developing embryo.
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Affiliation(s)
- Juan M Losada
- Pomology Department, Aula Dei Experimental Station-CSIC, Avda Montañana 1005, 50059, Saragossa, Spain.
- Arnold Arboretum of Harvard University, 1300 Centre St., Boston, MA, 02131, USA.
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora-CSIC-UMA, Avda. Dr. Wienberg s/n. Algarrobo-Costa, 29750, Málaga, Spain.
| | - María Herrero
- Pomology Department, Aula Dei Experimental Station-CSIC, Avda Montañana 1005, 50059, Saragossa, Spain
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Costa M, Pereira AM, Rudall PJ, Coimbra S. Immunolocalization of arabinogalactan proteins (AGPs) in reproductive structures of an early-divergent angiosperm, Trithuria (Hydatellaceae). Ann Bot 2013. [PMID: 23186834 PMCID: PMC3555524 DOI: 10.1093/aob/mcs256] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
BACKGROUND AND AIMS Trithuria is the sole genus of Hydatellaceae, a family of the early-divergent angiosperm lineage Nymphaeales (water-lilies). In this study different arabinogalactan protein (AGP) epitopes in T. submersa were evaluated in order to understand the diversity of these proteins and their functions in flowering plants. METHODS Immunolabelling of different AGPs and pectin epitopes in reproductive structures of T. submersa at the stage of early seed development was achieved by immunofluorescence of specific antibodies. KEY RESULTS AGPs in Trithuria pistil tissues could be important as structural proteins and also as possible signalling molecules. Intense labelling was obtained with anti-AGP antibodies both in the anthers and in the intine wall, the latter associated with pollen tube emergence. CONCLUSIONS AGPs could play a significant role in Trithuria reproduction, due to their specific presence in the pollen tube pathway. The results agree with labellings obtained for Arabidopsis and confirms the importance of AGPs in angiosperm reproductive structures as essential structural components and probably important signalling molecules.
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Affiliation(s)
- Mário Costa
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Edifício FC4 Rua do Campo Alegre 4169-007 Porto, Portugal
- BioFIG, Center for Biodiversity, Functional and Integrative Genomics, Portugal
| | - Ana Marta Pereira
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Edifício FC4 Rua do Campo Alegre 4169-007 Porto, Portugal
- BioFIG, Center for Biodiversity, Functional and Integrative Genomics, Portugal
| | - Paula J. Rudall
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AAB, UK
| | - Sílvia Coimbra
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Edifício FC4 Rua do Campo Alegre 4169-007 Porto, Portugal
- BioFIG, Center for Biodiversity, Functional and Integrative Genomics, Portugal
- For correspondence. E-mail
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Abstract
Gamete formation is an important step in the life cycle of sexually reproducing organisms. In flowering plants, haploid spores are formed after the meiotic division of spore mother cells. These spores develop into male and female gametophytes containing gametes after undergoing mitotic divisions. In the female, the megaspore mother cell undergoes meiosis forming four megaspores, of which one is functional and three degenerate. The megaspore then undergoes three mitotic cycles thus generating an embryo sac with eight nuclei. The embryo sac undergoes cellularization to form the mature seven-celled female gametophyte. Entry into and progression through meiosis is essential for megasporogenesis and subsequent megagametogenesis, but control of this process is not well understood. FOUR LIPS (FLP) and its paralogue MYB88, encoding R2R3 MYB transcription factors, have been extensively studied for their role in limiting the terminal division in stomatal development by direct regulation of the expression of cell cycle genes. Here it is demonstrated that FLP and MYB88 also regulate female reproduction. Both FLP and MYB88 are expressed during ovule development and their loss significantly increases the number of ovules produced by the placenta. Despite the presence of excess ovules, single and double mutants exhibit reduced seed set due to reduced female fertility. The sterility results at least in part from defective meiotic entry and progression. Therefore, FLP and MYB88 are important regulators of entry into megasporogenesis, and probably act via the regulation of cell cycle genes.
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Affiliation(s)
- Srilakshmi Makkena
- Plant Cellular and Molecular Biology Graduate Program, The Ohio State University, Columbus, OH 43210, USA
- Department of Molecular Genetics, The Ohio State University,Columbus, OH 43210, USA
| | - Eunkyoung Lee
- Department of Botany, The University of British ColumbiaVancouver, BC, Canada V6T 1Z4
| | - Fred D. Sack
- Department of Botany, The University of British ColumbiaVancouver, BC, Canada V6T 1Z4
| | - Rebecca S. Lamb
- Department of Molecular Genetics, The Ohio State University,Columbus, OH 43210, USA
- To whom correspondence should be addressed. E-mail:
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Higashiyama T. [Intercellular signaling in fertilization processes of flowering plants]. Tanpakushitsu Kakusan Koso 2008; 53:1267-1274. [PMID: 18681180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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Alandete-Saez M, Ron M, McCormick S. GEX3, expressed in the male gametophyte and in the egg cell of Arabidopsis thaliana, is essential for micropylar pollen tube guidance and plays a role during early embryogenesis. Mol Plant 2008; 1:586-98. [PMID: 19825564 DOI: 10.1093/mp/ssn015] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Double fertilization in flowering plants occurs when the two sperm cells, carried by the pollen tube, are released in a synergid cell of the embryo sac and then fertilize the egg and the central cell. Proteins on the surfaces of the sperm, egg, central, and synergid cells might be important for guidance and recognition/fusion of the gametes. Here, we present functional analyses of Arabidopsis GEX3, which encodes a plasma membrane-localized protein that has homologs in other plants. GEX3 is expressed in both the vegetative and sperm cells of the male gametophyte and in the egg cell of the female gametophyte. Transgenic lines in which GEX3 was down-regulated or overexpressed, using the Arabidopsis GEX2 promoter, had reduced seed set. Reciprocal crosses and imaging after pollination with a reporter line showed that, in both cases, the defect causing reduced seed set occurred in the female. In the antisense lines, micropylar pollen tube guidance failed. In the overexpression lines, fertilization of mutant ovules was mostly blocked because pollen tube guidance failed, although, occasionally, non-viable embryos were formed. We conclude that properly regulated expression of GEX3 in the egg cell of Arabidopsis is essential for pollen tube guidance.
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Affiliation(s)
- Monica Alandete-Saez
- Department of Plant and Microbial Biology, USDA/ARS-UC-Berkeley, Albany, CA 94710, USA
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Chen YH, Li HJ, Shi DQ, Yuan L, Liu J, Sreenivasan R, Baskar R, Grossniklaus U, Yang WC. The central cell plays a critical role in pollen tube guidance in Arabidopsis. Plant Cell 2007; 19:3563-77. [PMID: 18055609 PMCID: PMC2174880 DOI: 10.1105/tpc.107.053967] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 10/28/2007] [Accepted: 11/04/2007] [Indexed: 05/18/2023]
Abstract
The sperm cell of flowering plants cannot migrate unaided and must be transported by the pollen tube cell of the male gametophyte to achieve successful fertilization. Long-distance pollen tube guidance is controlled by the seven-celled female gametophyte, the embryo sac. Previous reports showed that the synergid cell of the embryo sac is essential for pollen tube guidance. Here, we report the identification of a central cell guidance (ccg) mutant, which is defective in micropylar pollen tube guidance. CCG encodes a nuclear protein with an N-terminal conserved zinc beta-ribbon domain that is functionally interchangeable with that of TFIIB in yeast. This suggests that CCG might act as a transcription regulator for pollen tube guidance. CCG is expressed in the central cell of the female gametophyte. Expression of CCG in the central cell alone is sufficient to restore the normal pollen tube guidance phenotype, demonstrating that the central cell plays a critical role in pollen tube guidance.
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Affiliation(s)
- Yan-Hong Chen
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
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