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Wang H, Santuari L, Wijsman T, Wachsman G, Haase H, Nodine M, Scheres B, Heidstra R. Arabidopsis ribosomal RNA processing meerling mutants exhibit suspensor-derived polyembryony due to direct reprogramming of the suspensor. THE PLANT CELL 2024; 36:2550-2569. [PMID: 38513608 PMCID: PMC11218825 DOI: 10.1093/plcell/koae087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/06/2024] [Accepted: 02/27/2024] [Indexed: 03/23/2024]
Abstract
Embryo development in Arabidopsis (Arabidopsis thaliana) starts off with an asymmetric division of the zygote to generate the precursors of the embryo proper and the supporting extraembryonic suspensor. The suspensor degenerates as the development of the embryo proper proceeds beyond the heart stage. Until the globular stage, the suspensor maintains embryonic potential and can form embryos in the absence of the developing embryo proper. We report a mutant called meerling-1 (mrl-1), which shows a high penetrance of suspensor-derived polyembryony due to delayed development of the embryo proper. Eventually, embryos from both apical and suspensor lineages successfully develop into normal plants and complete their life cycle. We identified the causal mutation as a genomic rearrangement altering the promoter of the Arabidopsis U3 SMALL NUCLEOLAR RNA-ASSOCIATED PROTEIN 18 (UTP18) homolog that encodes a nucleolar-localized WD40-repeat protein involved in processing 18S preribosomal RNA. Accordingly, root-specific knockout of UTP18 caused growth arrest and accumulation of unprocessed 18S pre-rRNA. We generated the mrl-2 loss-of-function mutant and observed asynchronous megagametophyte development causing embryo sac abortion. Together, our results indicate that promoter rearrangement decreased UTP18 protein abundance during early stage embryo proper development, triggering suspensor-derived embryogenesis. Our data support the existence of noncell autonomous signaling from the embryo proper to prevent direct reprogramming of the suspensor toward embryonic fate.
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Affiliation(s)
- Honglei Wang
- Cluster of Plant Developmental Biology, Laboratory of Cell and Developmental Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Luca Santuari
- Cluster of Plant Developmental Biology, Laboratory of Molecular Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Tristan Wijsman
- Cluster of Plant Developmental Biology, Laboratory of Cell and Developmental Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Guy Wachsman
- Molecular Genetics, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Hannah Haase
- Cluster of Plant Developmental Biology, Laboratory of Molecular Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Michael Nodine
- Cluster of Plant Developmental Biology, Laboratory of Molecular Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Ben Scheres
- Cluster of Plant Developmental Biology, Laboratory of Molecular Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Renze Heidstra
- Cluster of Plant Developmental Biology, Laboratory of Cell and Developmental Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
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2
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Wu YN, Lu JY, Li S, Zhang Y. Are vacuolar dynamics crucial factors for plant cell division and differentiation? PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 344:112090. [PMID: 38636812 DOI: 10.1016/j.plantsci.2024.112090] [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: 02/14/2024] [Revised: 04/03/2024] [Accepted: 04/10/2024] [Indexed: 04/20/2024]
Abstract
Vacuoles are the largest membrane-bound organelles in plant cells, critical for development and environmental responses. Vacuolar dynamics indicate reversible changes of vacuoles in morphology, size, or numbers. In this review, we summarize current understandings of vacuolar dynamics in different types of plant cells, biological processes associated with vacuolar dynamics, and regulators controlling vacuolar dynamics. Specifically, we point out the possibility that vacuolar dynamics play key roles in cell division and differentiation, which are controlled by the nucleus. Finally, we propose three routes through which vacuolar dynamics actively participate in nucleus-controlled cellular activities.
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Affiliation(s)
- Ya-Nan Wu
- Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Jin-Yu Lu
- Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Sha Li
- College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Yan Zhang
- Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin 300071, China.
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3
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Ali MF, Muday GK. Reactive oxygen species are signaling molecules that modulate plant reproduction. PLANT, CELL & ENVIRONMENT 2024; 47:1592-1605. [PMID: 38282262 DOI: 10.1111/pce.14837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/04/2024] [Accepted: 01/15/2024] [Indexed: 01/30/2024]
Abstract
Reactive oxygen species (ROS) can serve as signaling molecules that are essential for plant growth and development but abiotic stress can lead to ROS increases to supraoptimal levels resulting in cellular damage. To ensure efficient ROS signaling, cells have machinery to locally synthesize ROS to initiate cellular responses and to scavenge ROS to prevent it from reaching damaging levels. This review summarizes experimental evidence revealing the role of ROS during multiple stages of plant reproduction. Localized ROS synthesis controls the formation of pollen grains, pollen-stigma interactions, pollen tube growth, ovule development, and fertilization. Plants utilize ROS-producing enzymes such as respiratory burst oxidase homologs and organelle metabolic pathways to generate ROS, while the presence of scavenging mechanisms, including synthesis of antioxidant proteins and small molecules, serves to prevent its escalation to harmful levels. In this review, we summarized the function of ROS and its synthesis and scavenging mechanisms in all reproductive stages from gametophyte development until completion of fertilization. Additionally, we further address the impact of elevated temperatures induced ROS on impairing these reproductive processes and of flavonol antioxidants in maintaining ROS homeostasis to minimize temperature stress to combat the impact of global climate change on agriculture.
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Affiliation(s)
- Mohammad Foteh Ali
- Department of Biology and Center for Molecular Signaling, Wake Forest University, Winston Salem, NC, United States
| | - Gloria K Muday
- Department of Biology and Center for Molecular Signaling, Wake Forest University, Winston Salem, NC, United States
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4
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Qin Z, Liang ZZ, Wu YN, Zhou XQ, Xu M, Jiang LW, Li S, Zhang Y. Embryo sac development relies on symplastic signals from ovular integuments in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:161-172. [PMID: 37381795 DOI: 10.1111/tpj.16368] [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: 11/28/2022] [Revised: 06/12/2023] [Accepted: 06/16/2023] [Indexed: 06/30/2023]
Abstract
Ovules are female reproductive organs of angiosperms, consisting of sporophytic integuments surrounding female gametophytes, that is, embryo sacs. Synchronization between integument growth and embryo sac development requires intracellular communication. However, signaling routes through which cells of the two generations communicate are unclear. We report that symplastic signals through plasmodesmata (PDs) of integuments are critical for the development of female gametophytes. Genetic interferences of PD biogenesis either by functional loss of CHOLINE TRANSPORTER-LIKE1 (CTL1) or by integument-specific expression of a mutated CALLOSE SYNTHASE 3 (cals3m) compromised PD formation in integuments and reduced fertility. Close examination of pINO:cals3m or ctl1 ovules indicated that female gametophytic development was either arrested at various stages after the formation of functional megaspores. In both cases, defective ovules could not attract pollen tubes, leading to the failure of fertilization. Results presented here demonstrate a key role of the symplastic route in sporophytic control of female gametophytic development.
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Affiliation(s)
- Zheng Qin
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tian'jin, 300017, China
| | - Zi-Zhen Liang
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, Centre for Cell & Developmental Biology, The Chinese University of Hong Kong, Hong Kong, China
| | - Ya-Nan Wu
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tian'jin, 300017, China
| | - Xue-Qing Zhou
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Meng Xu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Li-Wen Jiang
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, Centre for Cell & Developmental Biology, The Chinese University of Hong Kong, Hong Kong, China
| | - Sha Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Yan Zhang
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tian'jin, 300017, China
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5
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Qin Z, Wu YN, Li S, Zhang Y. Signaling between sporophytic integuments and developing female gametophyte during ovule development. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 335:111829. [PMID: 37574141 DOI: 10.1016/j.plantsci.2023.111829] [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: 05/05/2023] [Revised: 08/07/2023] [Accepted: 08/11/2023] [Indexed: 08/15/2023]
Abstract
Ovules are precursors of seeds and contain sporophytic integuments and gametophytic embryo sac. In Arabidopsis, embryo sac development requires highly synchronized morphogenesis of integument such that defects in integument growth often accompanies with a block in megagametogenesis, indicating that integument instructs the development of female gametophytes. In this mini review, we discuss signaling pathways through which integument cells mediate embryo sac development. We also propose ways to identify key signaling factors for the communication between integument and developing female gametophyte.
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Affiliation(s)
- Zheng Qin
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tian'jin 300071, China
| | - Ya-Nan Wu
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tian'jin 300071, China
| | - Sha Li
- College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Yan Zhang
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tian'jin 300071, China; College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China.
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6
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Hu X, Yu P, Zhang Y, Gao Z, Sun B, Wu W, Deng C, Abbas A, Hong Y, Sun L, Liu Q, Xue P, Wang B, Zhan X, Cao L, Cheng S. Mutation of DEFECTIVE EMBRYO SAC1 results in a low seed-setting rate in rice by regulating embryo sac development. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:1501-1516. [PMID: 36651501 PMCID: PMC10010608 DOI: 10.1093/jxb/erac506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
The seed-setting rate has a significant effect on grain yield in rice (Oryza sativa L.). Embryo sac development is essential for seed setting; however, the molecular mechanism underlying this process remains unclear. Here, we isolated defective embryo sac1 (des1), a rice mutant with a low seed-setting rate. Cytological examination showed degenerated embryo sacs and reduced fertilization capacity in des1. Map-based cloning revealed a nonsense mutation in OsDES1, a gene that encodes a putative nuclear envelope membrane protein (NEMP)-domain-containing protein that is preferentially expressed in pistils. The OsDES1 mutation disrupts the normal formation of functional megaspores, which ultimately results in a degenerated embryo sac in des1. Reciprocal crosses showed that fertilization is abnormal and that the female reproductive organ is defective in des1. OsDES1 interacts with LONELY GUY (LOG), a cytokinin-activating enzyme that acts in the final step of cytokinin synthesis; mutation of LOG led to defective female reproductive organ development. These results demonstrate that OsDES1 functions in determining the rice seed-setting rate by regulating embryo sac development and fertilization. Our study sheds light on the function of NEMP-type proteins in rice reproductive development.
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Affiliation(s)
| | | | | | - Zhiqiang Gao
- Gannan Normal University, Ganzhou, Jiangxi, 341000, China
| | - Bin Sun
- Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China
| | - Weixun Wu
- China National Rice Research Institute, Hangzhou, Zhejiang, 311400, China
| | - Chenwei Deng
- Zhoukou Academy of Agricultural Sciences, Zhoukou, Henan, 466001, China
| | - Adil Abbas
- China National Rice Research Institute, Hangzhou, Zhejiang, 311400, China
| | - Yongbo Hong
- China National Rice Research Institute, Hangzhou, Zhejiang, 311400, China
| | - Lianping Sun
- China National Rice Research Institute, Hangzhou, Zhejiang, 311400, China
| | - Qunen Liu
- China National Rice Research Institute, Hangzhou, Zhejiang, 311400, China
| | - Pao Xue
- China National Rice Research Institute, Hangzhou, Zhejiang, 311400, China
| | - Beifang Wang
- China National Rice Research Institute, Hangzhou, Zhejiang, 311400, China
| | - Xiaodeng Zhan
- China National Rice Research Institute, Hangzhou, Zhejiang, 311400, China
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7
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Zhou Y, Fang W, Pang Z, Chen LY, Cai H, Ain NU, Chang MC, Ming R. AP1G2 Affects Mitotic Cycles of Female and Male Gametophytes in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2022; 13:924417. [PMID: 35873977 PMCID: PMC9301471 DOI: 10.3389/fpls.2022.924417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
During sexual reproduction in flowering plants, haploid spores are formed from meiosis of spore mother cells. The spores then undergo mitosis, develop into female and male gametophytes, and give rise to seeds after fertilization. We identified a female sterile mutant ap1g2-4 from EMS mutagenesis, and analyses of two T-DNA insertion mutants, ap1g2-1 +/- and ap1g2-3 -/-, and detected a partial female and male sterility. The ap1g2 mutant gametophyte development was arrested at one nuclear stage. A complementation test using a genomic sequence of AP1G2 with its native promoter restored the function in the three ap1g2 mutant lines. Transcriptome profiling of ap1g2 ovules revealed that four genes encoding clathrin assembly proteins PICALM5A/B and PICALM9A/B, which were involved in endocytosis, were downregulated, which were confirmed to interact with AP1G2 through yeast two-hybrid assays and BIFC analysis. Our result also demonstrated that RALFL4-8-15-19-26 CML16 and several calcium-dependent protein kinases, including CPK14-16-17, were all downregulated in the ovules of ap1g2-1 +/-. Moreover, Ca2+ concentration was low in impaired gametophytes. Therefore, we proposed that through interaction with PICALM5A/B and PICALM9A/B, AP1G2 may mediate gametogenesis accompanied by Ca2+ signaling in Arabidopsis. Our findings revealed a crucial role of AP1G2 in female and male gametogenesis in Arabidopsis and enhanced our understanding of the molecular mechanisms underpinning sexual reproduction in flowering plants.
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Affiliation(s)
- Yongmei Zhou
- FAFU and UIUC Joint Center for Genomics and Biotechnology, Key Laboratory of Sugarcane Biology and Genetic Breeding Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Wenqin Fang
- FAFU and UIUC Joint Center for Genomics and Biotechnology, Key Laboratory of Sugarcane Biology and Genetic Breeding Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ziqin Pang
- FAFU and UIUC Joint Center for Genomics and Biotechnology, Key Laboratory of Sugarcane Biology and Genetic Breeding Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Li-Yu Chen
- FAFU and UIUC Joint Center for Genomics and Biotechnology, Key Laboratory of Sugarcane Biology and Genetic Breeding Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Hanyang Cai
- FAFU and UIUC Joint Center for Genomics and Biotechnology, Key Laboratory of Sugarcane Biology and Genetic Breeding Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Noor-Ul- Ain
- FAFU and UIUC Joint Center for Genomics and Biotechnology, Key Laboratory of Sugarcane Biology and Genetic Breeding Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Men-Chi Chang
- Department of Agronomy, National Taiwan University, Taipei, Taiwan
| | - Ray Ming
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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8
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Qin Z, Wu YN, Sun TT, Ma T, Xu M, Pang C, Li SW, Li S. Arabidopsis RAN GTPases are critical for mitosis during male and female gametogenesis. FEBS Lett 2022; 596:1892-1903. [PMID: 35680649 DOI: 10.1002/1873-3468.14422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 11/09/2022]
Abstract
The development of male and female gametophytes is a prerequisite for successful propagation of angiosperms. The small GTPases RAN play fundamental roles in numerous cellular processes. Although RAN GTPases have been characterized in plants, their roles in cellular processes are far from understood. We report here that RAN GTPases in Arabidopsis are critical for gametophytic development. RAN1 loss-of-function showed no defects in gametophytic development likely due to redundancy. However, the expression of a dominant negative or constitutively active RAN1 resulted in gametophytic lethality. Genetic interference of RAN GTPases caused the arrest of pollen mitosis I and of mitosis of functional megaspores, implying a key role of properly regulated RAN activity in mitosis during gametophytic development.
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Affiliation(s)
- Zheng Qin
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tian'jin, China
| | - Ya-Nan Wu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Tian-Tian Sun
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Ting Ma
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Meng Xu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Chen Pang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Shan-Wei Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Sha Li
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tian'jin, China.,State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
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9
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Aslam M, Fakher B, Qin Y. Big Role of Small RNAs in Female Gametophyte Development. Int J Mol Sci 2022; 23:ijms23041979. [PMID: 35216096 PMCID: PMC8878111 DOI: 10.3390/ijms23041979] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/02/2022] [Accepted: 02/09/2022] [Indexed: 02/04/2023] Open
Abstract
In living organisms, sexual reproduction relies on the successful development of the gametes. Flowering plants produce gametes in the specialized organs of the flower, the gametophytes. The female gametophyte (FG), a multicellular structure containing female gametes (egg cell and central cell), is often referred to as an embryo sac. Intriguingly, several protein complexes, molecular and genetic mechanisms participate and tightly regulate the female gametophyte development. Recent evidence indicates that small RNA (sRNA) mediated pathways play vital roles in female gametophyte development and specification. Here, we present an insight into our understanding and the recent updates on the molecular mechanism of different players of small RNA-directed regulatory pathways during ovule formation and growth.
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Affiliation(s)
- Mohammad Aslam
- Guangxi Key Lab of Sugarcane Biology, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Agriculture, Guangxi University, Nanning 530004, China;
- Center for Genomics and Biotechnology, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China;
| | - Beenish Fakher
- Center for Genomics and Biotechnology, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China;
| | - Yuan Qin
- Guangxi Key Lab of Sugarcane Biology, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Agriculture, Guangxi University, Nanning 530004, China;
- Center for Genomics and Biotechnology, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China;
- Correspondence:
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10
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Liu F, Li JP, Li LS, Liu Q, Li SW, Song ML, Li S, Zhang Y. The canonical α-SNAP is essential for gametophytic development in Arabidopsis. PLoS Genet 2021; 17:e1009505. [PMID: 33886546 PMCID: PMC8096068 DOI: 10.1371/journal.pgen.1009505] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 05/04/2021] [Accepted: 03/24/2021] [Indexed: 12/26/2022] Open
Abstract
The development of male and female gametophytes is a pre-requisite for successful reproduction of angiosperms. Factors mediating vesicular trafficking are among the key regulators controlling gametophytic development. Fusion between vesicles and target membranes requires the assembly of a fusogenic soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNAREs) complex, whose disassembly in turn ensures the recycle of individual SNARE components. The disassembly of post-fusion SNARE complexes is controlled by the AAA+ ATPase N-ethylmaleimide-sensitive factor (Sec18/NSF) and soluble NSF attachment protein (Sec17/α-SNAP) in yeast and metazoans. Although non-canonical α-SNAPs have been functionally characterized in soybeans, the biological function of canonical α-SNAPs has yet to be demonstrated in plants. We report here that the canonical α-SNAP in Arabidopsis is essential for male and female gametophytic development. Functional loss of the canonical α-SNAP in Arabidopsis results in gametophytic lethality by arresting the first mitosis during gametogenesis. We further show that Arabidopsis α-SNAP encodes two isoforms due to alternative splicing. Both isoforms interact with the Arabidopsis homolog of NSF whereas have distinct subcellular localizations. The presence of similar alternative splicing of human α-SNAP indicates that functional distinction of two α-SNAP isoforms is evolutionarily conserved.
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Affiliation(s)
- Fei Liu
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, China
| | - Ji-Peng Li
- State Key laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Lu-Shen Li
- State Key laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Qi Liu
- State Key laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Shan-Wei Li
- State Key laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Ming-Lei Song
- State Key laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Sha Li
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, China
- State Key laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
- * E-mail: (SL); (YZ)
| | - Yan Zhang
- State Key laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
- * E-mail: (SL); (YZ)
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11
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Wei SJ, Chai S, Zhu RM, Duan CY, Zhang Y, Li S. HUA ENHANCER1 Mediates Ovule Development. FRONTIERS IN PLANT SCIENCE 2020; 11:397. [PMID: 32351522 PMCID: PMC7174553 DOI: 10.3389/fpls.2020.00397] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 03/19/2020] [Indexed: 05/03/2023]
Abstract
Ovules are female reproductive organs of angiosperms, containing sporophytic integuments and gametophytic embryo sacs. After fertilization, embryo sacs develop into embryos and endosperm whereas integuments into seed coat. Ovule development is regulated by transcription factors (TF) whose expression is often controlled by microRNAs. Mutations of Arabidopsis DICER-LIKE 1 (DCL1), a microRNA processing protein, caused defective ovule development and reduced female fertility. However, it was not clear whether other microRNA processing proteins participate in this process and how defective ovule development influenced female fertility. We report that mutations of HUA ENHANCER1 (HEN1) and HYPONASTIC LEAVES 1 (HYL1) interfered with integument growth. The sporophytic defect caused abnormal embryo sac development and inability of mutant ovules to attract pollen tubes, leading to reduced female fertility. We show that the role of HEN1 in integument growth is cell-autonomous. Although AUXIN RESPONSE FACTOR 6 (ARF6) and ARF8 were ectopically expressed in mutant ovules, consistent with the reduction of microRNA167 in hen1, introducing arf6;arf8 did not suppress ovule defects of hen1, suggesting the involvement of more microRNAs in this process. Results presented indicate that the microRNA processing machinery is critical for ovule development and seed production through multiple microRNAs and their targets.
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12
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Liu HH, Xiong F, Duan CY, Wu YN, Zhang Y, Li S. Importin β4 Mediates Nuclear Import of GRF-Interacting Factors to Control Ovule Development in Arabidopsis. PLANT PHYSIOLOGY 2019; 179:1080-1092. [PMID: 30659067 PMCID: PMC6393798 DOI: 10.1104/pp.18.01135] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 01/08/2019] [Indexed: 05/06/2023]
Abstract
Ovule development is critical for seed development and plant reproduction. Multiple transcription factors (TFs) have been reported to mediate ovule development. However, it is not clear which intracellular components regulate these TFs during ovule development. After their synthesis, TFs are transported into the nucleus a process regulated by karyopherins commonly known as importin alpha and β. Around half of Arabidopsis (Arabidopsis thaliana) importin β-coding genes have been functionally characterized but only two with specific cargos have been identified. We report here that Arabidopsis IMPORTIN β4 (IMB4) regulates ovule development through nucleocytoplasmic transport of transcriptional coactivator growth regulating factors-interacting factors (GIFs). Mutations in IMB4 impaired ovule development by affecting integument growth. imb4 mutants were also defective in embryo sac development, leading to partial female sterility. IMB4 directly interacts with GIFs and is critical for the nucleocytoplasmic transport of GIF1. Finally, functional loss of GIFs resulted in ovule defects similar to those in imb4 mutants, whereas enhanced expression of GIF1 partially restored the fertility of imb4 The results presented here uncover a novel genetic pathway regulating ovule development and reveal the upstream regulator of GIFs.
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Affiliation(s)
- Hai-Hong Liu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Feng Xiong
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Cun-Ying Duan
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Ya-Nan Wu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Yan Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Sha Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
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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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Giesbers AKJ, den Boer E, Ulen JJWEH, van Kaauwen MPW, Visser RGF, Niks RE, Jeuken MJW. Patterns of Transmission Ratio Distortion in Interspecific Lettuce Hybrids Reveal a Sex-Independent Gametophytic Barrier. Genetics 2019; 211:263-276. [PMID: 30401697 PMCID: PMC6325705 DOI: 10.1534/genetics.118.301566] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 10/30/2018] [Indexed: 11/18/2022] Open
Abstract
Interspecific crosses can result in progeny with reduced vitality or fertility due to genetic incompatibilities between species, a phenomenon known as hybrid incompatibility (HI). HI is often caused by a bias against deleterious allele combinations, which results in transmission ratio distortion (TRD). Here, we determined the genome-wide distribution of HI between wild lettuce, Lactuca saligna, and cultivated lettuce, L. sativa, in a set of backcross inbred lines (BILs) with single introgression segments from L. saligna introgressed into a L. sativa genetic background. Almost all BILs contained an introgression segment in a homozygous state except a few BILs, for which we were able to obtain only a single heterozygous introgression. Their inbred progenies displayed severe TRD with a bias toward the L. sativa allele and complete nontransmission of the homozygous L. saligna introgression, i.e., absolute HI. These HI might be caused by deleterious heterospecific allele combinations at two loci. We used an multilocus segregating interspecific F2 population to identify candidate conspecific loci that can nullify the HI in BILs. Segregation analysis of developed double-introgression progenies showed nullification of three HI and proved that these HI are explained by nuclear pairwise incompatibilities. One of these digenic HI showed 29% reduced seed set and its pattern of TRD pointed to a sex-independent gametophytic barrier. Namely, this HI was caused by complete nontransmission of one heterospecific allele combination at the haploid stage, surprisingly in both male and female gametophytes. Our study shows that two-locus incompatibility systems contribute to reproductive barriers among Lactuca species.
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Affiliation(s)
- Anne K J Giesbers
- Plant Breeding, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
| | - Erik den Boer
- Plant Breeding, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
| | | | | | - Richard G F Visser
- Plant Breeding, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
| | - Rients E Niks
- Plant Breeding, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
| | - Marieke J W Jeuken
- Plant Breeding, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
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Zhu Q, Zhang XL, Nadir S, DongChen WH, Guo XQ, Zhang HX, Li CY, Chen LJ, Lee DS. A LysM Domain-Containing Gene OsEMSA1 Involved in Embryo sac Development in Rice ( Oryza sativa L.). FRONTIERS IN PLANT SCIENCE 2017; 8:1596. [PMID: 28979272 PMCID: PMC5611485 DOI: 10.3389/fpls.2017.01596] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 08/30/2017] [Indexed: 06/07/2023]
Abstract
The embryo sac plays a vital role in sexual reproduction of angiosperms. LysM domain containing proteins with multiple lysin motifs are widespread proteins and are involved in plant defense responses against fungal chitins and bacterial peptidoglycans. Various studies have reported the role of LysM domain-containing proteins in plant defense mechanisms but their involvement in sexual reproduction remains largely unknown. Here, we report the involvement of a LysM domain-containing gene, EMBRYO SAC 1 (OsEMSA1), in the sexual reproduction of rice. The gene encoded a LysM domain-containing protein that was necessary for embryo sac development and function. The gene was expressed in root, stem, leaf tissues, panicle and ovaries and had some putative role in hormone regulation. Suppression of OsEMSA1 expression resulted in a defective embryo sac with poor differentiation of gametophytic cells, which consequently failed to attract pollen tubes and so reduced the panicle seed-setting rate. Our data offers new insight into the functions of LysM domain-containing proteins in rice.
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Affiliation(s)
- Qian Zhu
- Rice Research Institute, Yunnan Agricultural UniversityKunming, China
| | - Xiao-Ling Zhang
- Rice Research Institute, Yunnan Agricultural UniversityKunming, China
| | - Sadia Nadir
- Rice Research Institute, Yunnan Agricultural UniversityKunming, China
- Department of Chemistry, University of Science and TechnologyBannu, Pakistan
| | - Wen-Hua DongChen
- Rice Research Institute, Yunnan Agricultural UniversityKunming, China
| | - Xiao-Qiong Guo
- Rice Research Institute, Yunnan Agricultural UniversityKunming, China
| | - Hui-Xin Zhang
- Rice Research Institute, Yunnan Agricultural UniversityKunming, China
| | - Cheng-Yun Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural UniversityKunming, China
- Key Laboratory for Agricultural Biodiversity and Pest Management of China Education Ministry, Yunnan Agricultural UniversityKunming, China
| | - Li-Juan Chen
- Rice Research Institute, Yunnan Agricultural UniversityKunming, China
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural UniversityKunming, China
| | - Dong-Sun Lee
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural UniversityKunming, China
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Hao L, Wei X, Zhu J, Shi J, Liu J, Gu H, Tsuge T, Qu LJ. SNAIL1 is essential for female gametogenesis in Arabidopsis thaliana. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2017; 59:629-641. [PMID: 28776932 DOI: 10.1111/jipb.12572] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 08/02/2017] [Indexed: 06/07/2023]
Abstract
Two yeast Brix family members Ssf1 and Ssf2, involved in large ribosomal subunit synthesis, are essential for yeast cell viability and mating efficiency. Their putative homologs exist in the Arabidopsis genome; however, their role in plant development is unknown. Here, we show that Arabidopsis thaliana SNAIL1 (AtSNAIL1), a protein sharing high sequence identity with yeast Ssf1 and Ssf2, is critical to mitosis progression of female gametophyte development. The snail1 homozygous mutant was nonviable and its heterozygous mutant was semi-sterile with shorter siliques. The mutation in SNAIL1 led to absence of female transmission and reduced male transmission. Further phenotypic analysis showed that the synchronic development of female gametophyte in the snail1 heterozygous mutant was greatly impaired and the snail1 pollen tube growth, in vivo, was also compromised. Furthermore, SNAIL1 was a nucleolar-localized protein with a putative role in protein synthesis. Our data suggest that SNAIL1 may function in ribosome biogenesis like Ssf1 and Ssf2 and plays an important role during megagametogenesis in Arabidopsis.
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Affiliation(s)
- Lihong Hao
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
| | - Xiaolin Wei
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
| | - Jiulei Zhu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
| | - Jiao Shi
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
| | - Jingjing Liu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
- National Plant Gene Research Center (Beijing), Beijing 100101, China
| | - Hongya Gu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
- National Plant Gene Research Center (Beijing), Beijing 100101, China
| | - Tomohiko Tsuge
- Institute for Chemical Research, Kyoto University, Gokasho Uji, Kyoto 611-0011, Japan
| | - Li-Jia Qu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
- National Plant Gene Research Center (Beijing), Beijing 100101, China
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Galla G, Zenoni S, Avesani L, Altschmied L, Rizzo P, Sharbel TF, Barcaccia G. Pistil Transcriptome Analysis to Disclose Genes and Gene Products Related to Aposporous Apomixis in Hypericum perforatum L. FRONTIERS IN PLANT SCIENCE 2017; 8:79. [PMID: 28203244 PMCID: PMC5285387 DOI: 10.3389/fpls.2017.00079] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/13/2017] [Indexed: 05/19/2023]
Abstract
Unlike sexual reproduction, apomixis encompasses a number of reproductive strategies, which permit maternal genome inheritance without genetic recombination and syngamy. The key biological features of apomixis are the circumvention of meiosis (i.e., apomeiosis), the differentiation of unreduced embryo sacs and egg cells, and their autonomous development in functional embryos through parthenogenesis, and the formation of viable endosperm either via fertilization-independent means or following fertilization with a sperm cell. Despite the importance of apomixis for breeding of crop plants and although much research has been conducted to study this process, the genetic control of apomixis is still not well understood. Hypericum perforatum is becoming an attractive model system for the study of aposporous apomixis. Here we report results from a global gene expression analysis of H. perforatum pistils collected from sexual and aposporous plant accessions for the purpose of identifying genes, biological processes and molecular functions associated with the aposporous apomixis pathway. Across two developmental stages corresponding to the expression of aposporous apomeiosis and parthenogenesis in ovules, a total of 224 and 973 unigenes were found to be significantly up- and down-regulated with a fold change ≥ 2 in at least one comparison, respectively. Differentially expressed genes were enriched for multiple gene ontology (GO) terms, including cell cycle, DNA metabolic process, and single-organism cellular process. For molecular functions, the highest scores were recorded for GO terms associated with DNA binding, DNA (cytosine-5-)-methyltransferase activity and heterocyclic compound binding. As deregulation of single components of the sexual developmental pathway is believed to be a trigger of the apomictic reproductive program, all genes involved in sporogenesis, gametogenesis and response to hormonal stimuli were analyzed in great detail. Overall, our data suggest that phenotypic expression of apospory is concomitant with the modulation of key genes involved in the sexual reproductive pathway. Furthermore, based on gene annotation and co-expression, we underline a putative role of hormones and key actors playing in the RNA-directed DNA methylation pathway in regulating the developmental changes occurring during aposporous apomixis in H. perforatum.
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Affiliation(s)
- Giulio Galla
- Laboratory of Genomics, Department of Agronomy, Food, Natural Resources, Animals and Environment, University of PadovaPadova, Italy
- *Correspondence: Giulio Galla
| | - Sara Zenoni
- Department of Biotechnology, University of VeronaVerona, Italy
| | - Linda Avesani
- Department of Biotechnology, University of VeronaVerona, Italy
| | - Lothar Altschmied
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant ResearchGatersleben, Germany
| | - Paride Rizzo
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant ResearchGatersleben, Germany
- Department of Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant ResearchGatersleben, Germany
| | - Timothy F. Sharbel
- Department of Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant ResearchGatersleben, Germany
| | - Gianni Barcaccia
- Laboratory of Genomics, Department of Agronomy, Food, Natural Resources, Animals and Environment, University of PadovaPadova, Italy
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Pereira AM, Lopes AL, Coimbra S. Arabinogalactan Proteins as Interactors along the Crosstalk between the Pollen Tube and the Female Tissues. FRONTIERS IN PLANT SCIENCE 2016; 7:1895. [PMID: 28018417 PMCID: PMC5159419 DOI: 10.3389/fpls.2016.01895] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/30/2016] [Indexed: 05/19/2023]
Abstract
Arabinogalactan proteins (AGPs) have long been considered to be implicated in several steps of the reproductive process of flowering plants. Pollen tube growth along the pistil tissues requires a multiplicity of signaling pathways to be activated and turned off precisely, at crucial timepoints, to guarantee successful fertilization and seed production. In the recent years, an outstanding effort has been made by the plant reproduction scientific community in order to better understand this process. This resulted in the discovery of a fairly substantial number of new players essential for reproduction, as well as their modes of action and interactions. Besides all the indications of AGPs involvement in reproduction, there were no convincing evidences about it. Recently, several studies came out to prove what had long been suggested about this complex family of glycoproteins. AGPs consist of a large family of hydroxyproline-rich proteins, predicted to be anchored to the plasma membrane and extremely rich in sugars. These two last characteristics always made them perfect candidates to be involved in signaling mechanisms, in several plant developmental processes. New findings finally relate AGPs to concrete functions in plant reproduction. In this review, it is intended not only to describe how different molecules and signaling pathways are functioning to achieve fertilization, but also to integrate the recent discoveries about AGPs along this process.
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Affiliation(s)
- Ana M. Pereira
- Departamento de Biologia, Faculdade de Ciências da Universidade do PortoPorto, Portugal
- Biosystems and Integrative Sciences InstitutePorto, Portugal
| | - Ana L. Lopes
- Departamento de Biologia, Faculdade de Ciências da Universidade do PortoPorto, Portugal
- Biosystems and Integrative Sciences InstitutePorto, Portugal
| | - Sílvia Coimbra
- Departamento de Biologia, Faculdade de Ciências da Universidade do PortoPorto, Portugal
- Biosystems and Integrative Sciences InstitutePorto, Portugal
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Abstract
Flowering plants, like placental mammals, have an extensive maternal contribution toward progeny development. Plants are distinguished from animals by a genetically active haploid phase of growth and development between meiosis and fertilization, called the gametophyte. Flowering plants are further distinguished by the process of double fertilization that produces sister progeny, the endosperm and the embryo, of the seed. Because of this, there is substantial gene expression in the female gametophyte that contributes to the regulation of growth and development of the seed. A primary function of the endosperm is to provide growth support to its sister embryo. Several mutations in Zea mays subsp. mays have been identified that affect the contribution of the mother gametophyte to the seed. The majority affect both the endosperm and the embryo, although some embryo-specific effects have been observed. Many alter the pattern of expression of a marker for the basal endosperm transfer layer, a tissue that transports nutrients from the mother plant to the developing seed. Many of them cause abnormal development of the female gametophyte prior to fertilization, revealing potential cellular mechanisms of maternal control of seed development. These effects include reduced central cell size, abnormal architecture of the central cell, abnormal numbers and morphology of the antipodal cells, and abnormal egg cell morphology. These mutants provide insight into the logic of seed development, including necessary features of the gametes and supporting cells prior to fertilization, and set up future studies on the mechanisms regulating maternal contributions to the seed.
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Gene Expression Profiles in Rice Developing Ovules Provided Evidence for the Role of Sporophytic Tissue in Female Gametophyte Development. PLoS One 2015; 10:e0141613. [PMID: 26506227 PMCID: PMC4624635 DOI: 10.1371/journal.pone.0141613] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/09/2015] [Indexed: 12/21/2022] Open
Abstract
The development of ovule in rice (Oryza sativa) is vital during its life cycle. To gain more understanding of the molecular events associated with the ovule development, we used RNA sequencing approach to perform transcriptome-profiling analysis of the leaf and ovules at four developmental stages. In total, 25,401, 23,343, 23,647 and 23,806 genes were identified from the four developmental stages of the ovule, respectively. We identified a number of differently expressed genes (DEGs) from three adjacent stage comparisons, which may play crucial roles in ovule development. The DEGs were then conducted functional annotations and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses. Genes related to cellular component biogenesis, membrane-bounded organelles and reproductive regulation were identified to be highly expressed during the ovule development. Different expression levels of auxin-related and cytokinin-related genes were also identified at various stages, providing evidence for the role of sporophytic ovule tissue in female gametophyte development from the aspect of gene expression. Generally, an overall transcriptome analysis for rice ovule development has been conducted. These results increased our knowledge of the complex molecular and cellular events that occur during the development of rice ovule and provided foundation for further studies on rice ovule development.
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De novo sequencing of the Hypericum perforatum L. flower transcriptome to identify potential genes that are related to plant reproduction sensu lato. BMC Genomics 2015; 16:254. [PMID: 25887758 PMCID: PMC4451943 DOI: 10.1186/s12864-015-1439-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 03/06/2015] [Indexed: 02/07/2023] Open
Abstract
Background St. John’s wort (Hypericum perforatum L.) is a medicinal plant that produces important metabolites with antidepressant and anticancer activities. Recently gained biological information has shown that this species is also an attractive model system for the study of a naturally occurring form of asexual reproduction called apomixis, which allows cloning plants through seeds. In aposporic gametogenesis, one or multiple somatic cells belonging to the ovule nucellus change their fate by dividing mitotically and developing functionally unreduced embryo sacs by mimicking sexual gametogenesis. Although the introduction of apomixis into agronomically important crops could have revolutionary implications for plant breeding, the genetic control of this mechanism of seed formation is still not well understood for most of the model species investigated so far. We used Roche 454 technology to sequence the entire H. perforatum flower transcriptome of whole flower buds and single flower verticils collected from obligately sexual and unrelated highly or facultatively apomictic genotypes, which enabled us to identify RNAs that are likely exclusive to flower organs (i.e., sepals, petals, stamens and carpels) or reproductive strategies (i.e., sexual vs. apomictic). Results Here we sequenced and annotated the flower transcriptome of H. perforatum with particular reference to reproductive organs and processes. In particular, in our study we characterized approximately 37,000 transcripts found expressed in male and/or female reproductive organs, including tissues or cells of sexual and apomictic flower buds. Ontological annotation was applied to identify major biological processes and molecular functions involved in flower development and plant reproduction. Starting from this dataset, we were able to recover and annotate a large number of transcripts related to meiosis, gametophyte/gamete formation, and embryogenesis, as well as genes that are exclusively or preferentially expressed in sexual or apomictic libraries. Real-Time RT-qPCR assays on pistils and anthers collected at different developmental stages from accessions showing alternative modes of reproduction were used to identify potential genes that are related to plant reproduction sensu lato in H. perforatum. Conclusions Our approach of sequencing flowers from two fully obligate sexual genotypes and two unrelated highly apomictic genotypes, in addition to different flower parts dissected from a facultatively apomictic accession, enabled us to analyze the complexity of the flower transcriptome according to its main reproductive organs as well as for alternative reproductive behaviors. Both annotation and expression data provided original results supporting the hypothesis that apomixis in H. perforatum relies upon spatial or temporal mis-expression of genes acting during female sexual reproduction. The present analyses aim to pave the way toward a better understanding of the molecular basis of flower development and plant reproduction, by identifying genes or RNAs that may differentiate or regulate the sexual and apomictic reproductive pathways in H. perforatum. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1439-y) contains supplementary material, which is available to authorized users.
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Lo KL, Wang LC, Chen IJ, Liu YC, Chung MC, Lo WS. Transcriptional consequence and impaired gametogenesis with high-grade aneuploidy in Arabidopsis thaliana. PLoS One 2014; 9:e114617. [PMID: 25514186 PMCID: PMC4267805 DOI: 10.1371/journal.pone.0114617] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 11/12/2014] [Indexed: 12/11/2022] Open
Abstract
Aneuploidy features a numerical chromosome variant that the number of chromosomes in the nucleus of a cell is not an exact multiple of the haploid number, which may have an impact on morphology and gene expression. Here we report a tertiary trisomy uncovered by characterizing a T-DNA insertion mutant (aur2-1/+) in the Arabidopsis (Arabidopsis thaliana) AURORA2 locus. Whole-genome analysis with DNA tiling arrays revealed a chromosomal translocation linked to the aur2-1 allele, which collectively accounted for a tertiary trisomy 2. Morphologic, cytogenetic and genetic analyses of aur2-1 progeny showed impaired male and female gametogenesis to various degrees and a tight association of the aur2-1 allele with the tertiary trisomy that was preferentially inherited. Transcriptome analysis showed overlapping and distinct gene expression profiles between primary and tertiary trisomy 2 plants, particularly genes involved in response to stress and various types of external and internal stimuli. Additionally, transcriptome and gene ontology analyses revealed an overrepresentation of nuclear-encoded organelle-related genes functionally involved in plastids, mitochondria and peroxisomes that were differentially expressed in at least three if not all Arabidopsis trisomics. These observations support a previous hypothesis that aneuploid cells have higher energy requirement to overcome the detrimental effects of an unbalanced genome. Moreover, our findings extend the knowledge of the complex nature of the T-DNA insertion event influencing plant genomic integrity by creating high-grade trisomy. Finally, gene expression profiling results provide useful information for future research to compare primary and tertiary trisomics for the effects of aneuploidy on plant cell physiology.
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Affiliation(s)
- Kuan-Lin Lo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Long-Chi Wang
- Biotechnology Center, National Chung-Hsing University, Taichung, Taiwan
| | - I-Ju Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Chen Liu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Mei-Chu Chung
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Wan-Sheng Lo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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Wunderlich M, Groß-Hardt R, Schöffl F. Heat shock factor HSFB2a involved in gametophyte development of Arabidopsis thaliana and its expression is controlled by a heat-inducible long non-coding antisense RNA. PLANT MOLECULAR BIOLOGY 2014; 85:541-50. [PMID: 24874772 PMCID: PMC4099531 DOI: 10.1007/s11103-014-0202-0] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 05/15/2014] [Indexed: 05/04/2023]
Abstract
Heat stress transcription factors (HSFs) are central regulators of the heat stress response. Plant HSFs of subgroup B lack a conserved sequence motif present in the transcriptional activation domain of class A-HSFs. Arabidopsis members were found to be involved in non-heat shock functions. In the present analysis we investigated the expression, regulation and function of HSFB2a. HSFB2a expression was counteracted by a natural long non-coding antisense RNA, asHSFB2a. In leaves, the antisense RNA gene is only expressed after heat stress and dependent on the activity of HSFA1a/HSFA1b. HSFB2a and asHSFB2a RNAs were also present in the absence of heat stress in the female gametophyte. Transgenic overexpression of HSFB2a resulted in a complete knock down of the asHSFB2a expression. Conversely, asHSFB2a overexpression leads to the absence of HSFB2a RNA. The knockdown of HSFB2a by asHSFB2a correlated with an improved, knockdown of asHSFB2a by HSFB2a overexpression with an impaired biomass production early in vegetative development. In both cases the development of female gametophytes was impaired. A T-DNA knock-out line did not segregate homozygous mutant plants, only heterozygots hsfB2a-tt1/+ were viable. Approximately 50% of the female gametophytes were arrested in early development, before mitosis 3, resulting in 45% of sterile ovules. Our analysis indicates that the "Yin-Yang" regulation of gene expression at the HSFB2a locus influences vegetative and gametophytic development in Arabidopsis.
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Affiliation(s)
- Markus Wunderlich
- ZMBP General Genetics, University of Tübingen, 72076 Tübingen, Germany
| | - Rita Groß-Hardt
- ZMBP Developmental Genetics, University of Tübingen, 72076 Tübingen, Germany
| | - Friedrich Schöffl
- ZMBP General Genetics, University of Tübingen, 72076 Tübingen, Germany
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Wang H, Liu R, Wang J, Wang P, Shen Y, Liu G. The Arabidopsis kinesin gene AtKin-1 plays a role in the nuclear division process during megagametogenesis. PLANT CELL REPORTS 2014; 33:819-828. [PMID: 24667993 DOI: 10.1007/s00299-014-1594-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/15/2014] [Accepted: 02/26/2014] [Indexed: 06/03/2023]
Abstract
Atkin - 1 , the only Kinesin-1 member of Arabidopsis thaliana , plays a role during female gametogenesis through regulation of nuclear division cycles. Kinesins are microtubule-dependent motor proteins found in eukaryotic organisms. They constitute a superfamily that can be further classified into at least 14 families. In the Kinesin-1 family, members from animal and fungi play roles in long-distance transport of organelles and vesicles. Although Kinesin-1-like sequences have been identified in higher plants, little is known about their function in plant cells, other than in a recently identified Kinesin-1-like protein in a rice pollen semi-sterile mutant. In this study, the gene encoding the only Kinesin-1 member in Arabidopsis, AtKin-1 was found to be specifically expressed in ovules and anthers. AtKin-1 loss-of-function mutants showed substantially aborted ovules in siliques, and this finding was supported by complementation testing. Reciprocal crossing between mutant and wild-type plants indicated that a defect in AtKin-1 results in partially aborted megagametophytes, with no observable effects on pollen fertility. Further observation of ovule development in the mutant pistils indicated that the enlargement of the megaspore was blocked and nuclear division arrested at the one-nucleate stage during embryo sac formation. Our data suggest that AtKin-1 plays a role in the nuclear division cycles during megagametogenesis.
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Affiliation(s)
- Haiqing Wang
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Plateau Institute of Biology, Chinese Academy of Sciences, 23 Xinning Road, Xining, 810001, China,
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Bleckmann A, Alter S, Dresselhaus T. The beginning of a seed: regulatory mechanisms of double fertilization. FRONTIERS IN PLANT SCIENCE 2014; 5:452. [PMID: 25309552 PMCID: PMC4160995 DOI: 10.3389/fpls.2014.00452] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 08/21/2014] [Indexed: 05/20/2023]
Abstract
THE LAUNCH OF SEED DEVELOPMENT IN FLOWERING PLANTS (ANGIOSPERMS) IS INITIATED BY THE PROCESS OF DOUBLE FERTILIZATION: two male gametes (sperm cells) fuse with two female gametes (egg and central cell) to form the precursor cells of the two major seed components, the embryo and endosperm, respectively. The immobile sperm cells are delivered by the pollen tube toward the ovule harboring the female gametophyte by species-specific pollen tube guidance and attraction mechanisms. After pollen tube burst inside the female gametophyte, the two sperm cells fuse with the egg and central cell initiating seed development. The fertilized central cell forms the endosperm while the fertilized egg cell, the zygote, will form the actual embryo and suspensor. The latter structure connects the embryo with the sporophytic maternal tissues of the developing seed. The underlying mechanisms of double fertilization are tightly regulated to ensure delivery of functional sperm cells and the formation of both, a functional zygote and endosperm. In this review we will discuss the current state of knowledge about the processes of directed pollen tube growth and its communication with the synergid cells resulting in pollen tube burst, the interaction of the four gametes leading to cell fusion and finally discuss mechanisms how flowering plants prevent multiple sperm cell entry (polyspermy) to maximize their reproductive success.
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Affiliation(s)
- Andrea Bleckmann
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of RegensburgRegensburg, Germany
| | - Svenja Alter
- Plant Breeding, Center of Life and Food Sciences Weihenstephan, Technische Universität MünchenFreising, Germany
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of RegensburgRegensburg, Germany
- *Correspondence: Thomas Dresselhaus, Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstrasse 18, 93053 Regensburg, Germany e-mail:
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Locascio A, Roig-Villanova I, Bernardi J, Varotto S. Current perspectives on the hormonal control of seed development in Arabidopsis and maize: a focus on auxin. FRONTIERS IN PLANT SCIENCE 2014; 5:412. [PMID: 25202316 PMCID: PMC4142864 DOI: 10.3389/fpls.2014.00412] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Accepted: 08/03/2014] [Indexed: 05/18/2023]
Abstract
The seed represents the unit of reproduction of flowering plants, capable of developing into another plant, and to ensure the survival of the species under unfavorable environmental conditions. It is composed of three compartments: seed coat, endosperm and embryo. Proper seed development depends on the coordination of the processes that lead to seed compartments differentiation, development and maturation. The coordination of these processes is based on the constant transmission/perception of signals by the three compartments. Phytohormones constitute one of these signals; gradients of hormones are generated in the different seed compartments, and their ratios comprise the signals that induce/inhibit particular processes in seed development. Among the hormones, auxin seems to exert a central role, as it is the only one in maintaining high levels of accumulation from fertilization to seed maturation. The gradient of auxin generated by its PIN carriers affects several processes of seed development, including pattern formation, cell division and expansion. Despite the high degree of conservation in the regulatory mechanisms that lead to seed development within the Spermatophytes, remarkable differences exist during seed maturation between Monocots and Eudicots species. For instance, in Monocots the endosperm persists until maturation, and constitutes an important compartment for nutrients storage, while in Eudicots it is reduced to a single cell layer, as the expanding embryo gradually replaces it during the maturation. This review provides an overview of the current knowledge on hormonal control of seed development, by considering the data available in two model plants: Arabidopsis thaliana, for Eudicots and Zea mays L., for Monocots. We will emphasize the control exerted by auxin on the correct progress of seed development comparing, when possible, the two species.
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Affiliation(s)
- Antonella Locascio
- Department of Agronomy Food Natural Resources Animals Environment - University of PadovaPadova, Italy
- IBMCP-CSIC, Universidad Politécnica de ValenciaValencia, Spain
- *Correspondence: Antonella Locascio, IBMCP-CSIC, Universidad Politécnica de Valencia, Avda de los Naranjos s/n, ed.8E, 46020 Valencia, Spain e-mail:
| | | | - Jamila Bernardi
- Istituto di Agronomia Genetica e Coltivazioni Erbacee, Università Cattolica del Sacro CuorePiacenza, Italy
| | - Serena Varotto
- Department of Agronomy Food Natural Resources Animals Environment - University of PadovaPadova, Italy
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Abiko M, Furuta K, Yamauchi Y, Fujita C, Taoka M, Isobe T, Okamoto T. Identification of proteins enriched in rice egg or sperm cells by single-cell proteomics. PLoS One 2013; 8:e69578. [PMID: 23936051 PMCID: PMC3723872 DOI: 10.1371/journal.pone.0069578] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 06/10/2013] [Indexed: 11/19/2022] Open
Abstract
In angiosperms, female gamete differentiation, fertilization, and subsequent zygotic development occur in embryo sacs deeply embedded in the ovaries. Despite their importance in plant reproduction and development, how the egg cell is specialized, fuses with the sperm cell, and converts into an active zygote for early embryogenesis remains unclear. This lack of knowledge is partly attributable to the difficulty of direct analyses of gametes in angiosperms. In the present study, proteins from egg and sperm cells obtained from rice flowers were separated by one-dimensional polyacrylamide gel electrophoresis and globally identified by highly sensitive liquid chromatography coupled with tandem mass spectroscopy. Proteome analyses were also conducted for seedlings, callus, and pollen grains to compare their protein expression profiles to those of gametes. The proteomics data have been deposited to the ProteomeXchange with identifier PXD000265. A total of 2,138 and 2,179 expressed proteins were detected in egg and sperm cells, respectively, and 102 and 77 proteins were identified as preferentially expressed in egg and sperm cells, respectively. Moreover, several rice or Arabidopsis lines with mutations in genes encoding the putative gamete-enriched proteins showed clear phenotypic defects in seed set or seed development. These results suggested that the proteomic data presented in this study are foundational information toward understanding the mechanisms of reproduction and early development in angiosperms.
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Affiliation(s)
- Mafumi Abiko
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan,
| | - Kensyo Furuta
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan,
| | - Yoshio Yamauchi
- Department of Chemistry, Tokyo Metropolitan University, Tokyo, Japan
| | - Chiharu Fujita
- Department of Chemistry, Tokyo Metropolitan University, Tokyo, Japan
| | - Masato Taoka
- Department of Chemistry, Tokyo Metropolitan University, Tokyo, Japan
| | - Toshiaki Isobe
- Department of Chemistry, Tokyo Metropolitan University, Tokyo, Japan
| | - Takashi Okamoto
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan,
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Cheng CY, Mathews DE, Schaller GE, Kieber JJ. Cytokinin-dependent specification of the functional megaspore in the Arabidopsis female gametophyte. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 73:929-940. [PMID: 23181607 DOI: 10.1111/tpj.12084] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 11/20/2012] [Accepted: 11/22/2012] [Indexed: 05/19/2023]
Abstract
The life cycle of higher plants alternates between the diploid sporophytic and the haploid gametophytic phases. In angiosperms, male and female gametophytes develop within the sporophyte. During female gametophyte (FG) development, a single archesporial cell enlarges and differentiates into a megaspore mother cell, which then undergoes meiosis to give rise to four megaspores. In most species of higher plants, including Arabidopsis thaliana, the megaspore closest to the chalaza develops into the functional megaspore (FM), and the remaining three megaspores degenerate. Here, we examined the role of cytokinin signaling in FG development. We characterized the FG phenotype in three triple mutants harboring non-overlapping T-DNA insertions in cytokinin AHK receptors. We demonstrate that even the strongest mutant is not a complete null for the cytokinin receptors. Only the strongest mutant displayed a near fully penetrant disruption of FG development, and the weakest triple ahk mutant had only a modest FG phenotype. This suggests that cytokinin signaling is essential for FG development, but that only a low threshold of signaling activity is required for this function. Furthermore, we demonstrate that there is elevated cytokinin signaling localized in the chalaza of the ovule, which is enhanced by the asymmetric localization of cytokinin biosynthetic machinery and receptors. We show that an FM-specific marker is absent in the multiple ahk ovules, suggesting that disruption of cytokinin signaling elements in Arabidopsis blocks the FM specification. Together, this study reveals a chalazal-localized sporophytic cytokinin signal that plays an important role in FM specification in FG development.
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Affiliation(s)
- Chia-Yi Cheng
- Biology Department, University of North Carolina, CB#3280, Chapel Hill, NC 27599, USA
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31
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Niedojadło K, Pięciński S, Smoliński DJ, Bednarska-Kozakiewicz E. Transcriptional activity of Hyacinthus orientalis L. female gametophyte cells before and after fertilization. PLANTA 2012; 236:153-69. [PMID: 22293855 PMCID: PMC3382649 DOI: 10.1007/s00425-012-1599-9] [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: 09/20/2011] [Accepted: 01/05/2012] [Indexed: 05/19/2023]
Abstract
We characterized three phases of Hyacinthus orientalis L. embryo sac development, in which the transcriptional activity of the cells differed using immunolocalization of incorporated 5′-bromouracil, the total RNA polymerase II pool and the hypo- (initiation) and hyperphosphorylated (elongation) forms of RNA Pol II. The first stage, which lasts from the multinuclear stage to cellularization, is a period of high transcriptional activity, probably related to the maturation of female gametophyte cells. The second stage, encompassing the period of embryo sac maturity and the progamic phase, involves the transcriptional silencing of cells that will soon undergo fusion with male gametes. During this period in the hyacinth egg cell, there are almost no newly formed transcripts, and only a small pool of RNA Pol II is present in the nucleus. The transcriptional activity of the central cell is only slightly higher than that observed in the egg cell. The post-fertilization stage is related to the transcriptional activation of the zygote and the primary endosperm cell. The rapid increase in the pool of newly formed transcripts in these cells is accompanied by an increase in the pool of RNA Pol II, and the pattern of enzyme distribution in the zygote nucleus is similar to that observed in the somatic cells of the ovule. Our data, together with the earlier results of Pięciński et al. (2008), indicate post-fertilization synthesis and the maturation of numerous mRNA transcripts, suggesting that fertilization in H. orientalis induces the activation of the zygote and endosperm genomes.
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Affiliation(s)
- Katarzyna Niedojadło
- Department of Cell Biology, Institute of General and Molecular Biology, Nicolaus Copernicus University, Gagarina 9, 87-100 Toruń, Poland.
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32
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Fertilization Recovery after Defective Sperm Cell Release in Arabidopsis. Curr Biol 2012; 22:1084-9. [DOI: 10.1016/j.cub.2012.03.069] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 03/27/2012] [Accepted: 03/28/2012] [Indexed: 11/18/2022]
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Sánchez-León N, Arteaga-Vázquez M, Alvarez-Mejía C, Mendiola-Soto J, Durán-Figueroa N, Rodríguez-Leal D, Rodríguez-Arévalo I, García-Campayo V, García-Aguilar M, Olmedo-Monfil V, Arteaga-Sánchez M, de la Vega OM, Nobuta K, Vemaraju K, Meyers BC, Vielle-Calzada JP. Transcriptional analysis of the Arabidopsis ovule by massively parallel signature sequencing. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:3829-42. [PMID: 22442422 PMCID: PMC3388818 DOI: 10.1093/jxb/ers075] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The life cycle of flowering plants alternates between a predominant sporophytic (diploid) and an ephemeral gametophytic (haploid) generation that only occurs in reproductive organs. In Arabidopsis thaliana, the female gametophyte is deeply embedded within the ovule, complicating the study of the genetic and molecular interactions involved in the sporophytic to gametophytic transition. Massively parallel signature sequencing (MPSS) was used to conduct a quantitative large-scale transcriptional analysis of the fully differentiated Arabidopsis ovule prior to fertilization. The expression of 9775 genes was quantified in wild-type ovules, additionally detecting >2200 new transcripts mapping to antisense or intergenic regions. A quantitative comparison of global expression in wild-type and sporocyteless (spl) individuals resulted in 1301 genes showing 25-fold reduced or null activity in ovules lacking a female gametophyte, including those encoding 92 signalling proteins, 75 transcription factors, and 72 RNA-binding proteins not reported in previous studies based on microarray profiling. A combination of independent genetic and molecular strategies confirmed the differential expression of 28 of them, showing that they are either preferentially active in the female gametophyte, or dependent on the presence of a female gametophyte to be expressed in sporophytic cells of the ovule. Among 18 genes encoding pentatricopeptide-repeat proteins (PPRs) that show transcriptional activity in wild-type but not spl ovules, CIHUATEOTL (At4g38150) is specifically expressed in the female gametophyte and necessary for female gametogenesis. These results expand the nature of the transcriptional universe present in the ovule of Arabidopsis, and offer a large-scale quantitative reference of global expression for future genomic and developmental studies.
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Affiliation(s)
- Nidia Sánchez-León
- Laboratorio Nacional de Genómica para la Biodiversidad y Departamento de Ingeniería Genética de Plantas, Cinvestav Irapuato CP36821 México
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34
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Mizzotti C, Mendes MA, Caporali E, Schnittger A, Kater MM, Battaglia R, Colombo L. The MADS box genes SEEDSTICK and ARABIDOPSIS Bsister play a maternal role in fertilization and seed development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 70:409-20. [PMID: 22176531 DOI: 10.1111/j.1365-313x.2011.04878.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The haploid generation of flowering plants develops within the sporophytic tissues of the ovule. After fertilization, the maternal seed coat develops in a coordinated manner with formation of the embryo and endosperm. In the arabidopsis bsister (abs) mutant, the endothelium, which is the most inner cell layer of the integuments that surround the haploid embryo sac, does not accumulate proanthocyanidins and the cells have an abnormal morphology. However, fertility is not affected in abs single mutants. SEEDSTICK regulates ovule identity redundantly with SHATTERPROOF 1 (SHP1) and SHP2 while a role in the control of fertility was not reported previously. Here we describe the characterization of the abs stk double mutant. This double mutant develops very few seeds due to both a reduced number of fertilized ovules and seed abortions later during development. Morphological analysis revealed a total absence of endothelium in this double mutant. Additionally, massive starch accumulation was observed in the embryo sac. The phenotype of the abs stk double mutant highlights the importance of the maternal-derived tissues, particularly the endothelium, for the development of the next generation.
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Affiliation(s)
- Chiara Mizzotti
- Dipartimento di Biologia, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
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Wang SQ, Shi DQ, Long YP, Liu J, Yang WC. GAMETOPHYTE DEFECTIVE 1, a putative subunit of RNases P/MRP, is essential for female gametogenesis and male competence in Arabidopsis. PLoS One 2012; 7:e33595. [PMID: 22509260 PMCID: PMC3324470 DOI: 10.1371/journal.pone.0033595] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Accepted: 02/13/2012] [Indexed: 01/15/2023] Open
Abstract
RNA biogenesis, including biosynthesis and maturation of rRNA, tRNA and mRNA, is a fundamental process that is critical for cell growth, division and differentiation. Previous studies showed that mutations in components involved in RNA biogenesis resulted in abnormalities in gametophyte and leaf development in Arabidopsis. In eukaryotes, RNases P/MRP (RNase mitochondrial RNA processing) are important ribonucleases that are responsible for processing of tRNA, and transcription of small non-coding RNAs. Here we report that Gametophyte Defective 1 (GAF1), a gene encoding a predicted protein subunit of RNases P/MRP, AtRPP30, plays a role in female gametophyte development and male competence. Embryo sacs were arrested at stages ranging from FG1 to FG7 in gaf1 mutant, suggesting that the progression of the gametophytic division during female gametogenesis was impaired in gaf1 mutant. In contrast, pollen development was not affected in gaf1. However, the fitness of the mutant pollen tube was weaker than that of the wild-type, leading to reduced transmission through the male gametes. GAF1 is featured as a typical RPP30 domain protein and interacts physically with AtPOP5, a homologue of RNases P/MRP subunit POP5 of yeast. Together, our data suggest that components of the RNases P/MRP family, such as RPP30, play important roles in gametophyte development and function in plants.
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Affiliation(s)
- Si-Qi Wang
- State Key Laboratory of Molecular Developmental Biology, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Dong-Qiao Shi
- State Key Laboratory of Molecular Developmental Biology, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- * E-mail: (DQS); (WCY)
| | - Yan-Ping Long
- State Key Laboratory of Molecular Developmental Biology, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Jie Liu
- State Key Laboratory of Molecular Developmental Biology, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Wei-Cai Yang
- State Key Laboratory of Molecular Developmental Biology, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- * E-mail: (DQS); (WCY)
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Awasthi A, Paul P, Kumar S, Verma SK, Prasad R, Dhaliwal HS. Abnormal endosperm development causes female sterility in rice insertional mutant OsAPC6. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 183:167-174. [PMID: 22195590 DOI: 10.1016/j.plantsci.2011.08.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 08/18/2011] [Accepted: 08/19/2011] [Indexed: 05/28/2023]
Abstract
A T-DNA insertional mutant OsAPC6 of rice, with gibberellic acid insensitivity and reduced height, had up to 45% reduced seed set. The insertion occurred on chromosome 3 of rice in the gene encoding one of the subunits of anaphase promoting complex/Cyclosome APC6. The primary mother cells of the mutant plants had normal meiosis, male gametophyte development and pollen viability. Confocal laser scanning microscopic (CLSM) studies of megagametophyte development showed abnormal mitotic divisions with reduced number or total absence of polar nuclei in about 30-35% megagametophytes of OsAPC6 mutant leading to failure of endosperm and hence embryo and seed development. Abnormal female gametophyte development, high sterility and segregation of tall and gibberellic acid sensitive plants without selectable marker Hpt in the selfed progeny of OsAPC6 mutant plants indicate that the mutant could be maintained in heterozygous condition. The abnormal mitotic divisions during megagametogenesis could be attributed to the inactivation of the APC6/CDC16 of anaphase promoting complex of rice responsible for cell cycle progression during megagametogenesis. Functional validation of the candidate gene through transcriptome profiling and RNAi is in progress.
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Affiliation(s)
- Anjali Awasthi
- Department of Biotechnology, Indian Institute of Technology, Roorkee-247667 India
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Yoo CM, Quan L, Blancaflor EB. Divergence and Redundancy in CSLD2 and CSLD3 Function During Arabidopsis Thaliana Root Hair and Female Gametophyte Development. FRONTIERS IN PLANT SCIENCE 2012; 3:111. [PMID: 22661983 PMCID: PMC3361707 DOI: 10.3389/fpls.2012.00111] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 05/08/2012] [Indexed: 05/21/2023]
Abstract
The Arabidopsis cellulose synthase-like D (CSLD) 2 and 3 genes are known to function in root hair development. Here, we show that these genes also play a role in female gametophyte development because csld2 csld3 double mutants were observed to have low seed set that could be traced to defects in female transmission efficiency. Cell biological studies of csld2 csld3 ovules showed synergid cell degeneration during megagametogenesis and reduced pollen tube penetration during fertilization. Although CSLD2 and CSLD3 function redundantly in female gametophyte development, detailed analyses of root hair phenotypes of progeny from genetic crosses between csld2 and csld3, suggest that CSLD3 might play a more prominent role than CSLD2 in root hair development. Phylogenetic and gene duplication studies of CSLD2 and CSLD3 homologs in Arabidopsis lyrata, Populus, Medicago, maize, and Physcomitrella were further performed to investigate the course of evolution for these genes. Our analyses indicate that the ancestor of land plants possibly contained two copies of CSLD genes, one of which developed into the CSLD5 lineage in flowering plants, and the other formed the CSLD1/2/3/4 clade. In addition, CSLD2 and CSLD3 likely originated from a recent genome-wide duplication event explaining their redundancy. Moreover, sliding-window dN/dS analysis showed that most of the coding regions of CSLD2 and CSLD3 have been under strong purifying selection pressure. However, the region that encodes the N-terminus of CSLD3 has been under relatively relaxed selection pressure as indicated by its high dN/dS value, suggesting that CSLD3 might have gained additional functions through more frequent non-synonymous sequence changes at the N-terminus, which could partly explain the more prominent role of CSLD3 during root hair development compared to CSLD2.
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Affiliation(s)
- Cheol-Min Yoo
- Plant Biology Division, The Samuel Roberts Noble FoundationArdmore, OK, USA
| | - Li Quan
- Plant Biology Division, The Samuel Roberts Noble FoundationArdmore, OK, USA
| | - Elison B. Blancaflor
- Plant Biology Division, The Samuel Roberts Noble FoundationArdmore, OK, USA
- *Correspondence: Elison B. Blancaflor, Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, USA. e-mail:
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38
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Palanivelu R, Tsukamoto T. Pathfinding in angiosperm reproduction: pollen tube guidance by pistils ensures successful double fertilization. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2011; 1:96-113. [PMID: 23801670 DOI: 10.1002/wdev.6] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Sexual reproduction in flowering plants is unique in multiple ways. Distinct multicellular gametophytes contain either a pair of immotile, haploid male gametes (sperm cells) or a pair of female gametes (haploid egg cell and homodiploid central cell). After pollination, the pollen tube, a cellular extension of the male gametophyte, transports both male gametes at its growing tip and delivers them to the female gametes to affect double fertilization. The pollen tube travels a long path and sustains its growth over a considerable amount of time in the female reproductive organ (pistil) before it reaches the ovule, which houses the female gametophyte. The pistil facilitates the pollen tube's journey by providing multiple, stage-specific, nutritional, and guidance cues along its path. The pollen tube interacts with seven different pistil cell types prior to completing its journey. Consequently, the pollen tube has a dynamic gene expression program allowing it to continuously reset and be receptive to multiple pistil signals as it migrates through the pistil. Here, we review the studies, including several significant recent advances, that led to a better understanding of the multitude of cues generated by the pistil tissues to assist the pollen tube in delivering the sperm cells to the female gametophyte. We also highlight the outstanding questions, draw attention to opportunities created by recent advances and point to approaches that could be undertaken to unravel the molecular mechanisms underlying pollen tube-pistil interactions.
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Schmidt A, Wuest SE, Vijverberg K, Baroux C, Kleen D, Grossniklaus U. Transcriptome analysis of the Arabidopsis megaspore mother cell uncovers the importance of RNA helicases for plant germline development. PLoS Biol 2011; 9:e1001155. [PMID: 21949639 PMCID: PMC3176755 DOI: 10.1371/journal.pbio.1001155] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 08/05/2011] [Indexed: 01/23/2023] Open
Abstract
Germ line specification is a crucial step in the life cycle of all organisms. For sexual plant reproduction, the megaspore mother cell (MMC) is of crucial importance: it marks the first cell of the plant "germline" lineage that gets committed to undergo meiosis. One of the meiotic products, the functional megaspore, subsequently gives rise to the haploid, multicellular female gametophyte that harbours the female gametes. The MMC is formed by selection and differentiation of a single somatic, sub-epidermal cell in the ovule. The transcriptional network underlying MMC specification and differentiation is largely unknown. We provide the first transcriptome analysis of an MMC using the model plant Arabidopsis thaliana with a combination of laser-assisted microdissection and microarray hybridizations. Statistical analyses identified an over-representation of translational regulation control pathways and a significant enrichment of DEAD/DEAH-box helicases in the MMC transcriptome, paralleling important features of the animal germline. Analysis of two independent T-DNA insertion lines suggests an important role of an enriched helicase, MNEME (MEM), in MMC differentiation and the restriction of the germline fate to only one cell per ovule primordium. In heterozygous mem mutants, additional enlarged MMC-like cells, which sometimes initiate female gametophyte development, were observed at higher frequencies than in the wild type. This closely resembles the phenotype of mutants affected in the small RNA and DNA-methylation pathways important for epigenetic regulation. Importantly, the mem phenotype shows features of apospory, as female gametophytes initiate from two non-sister cells in these mutants. Moreover, in mem gametophytic nuclei, both higher order chromatin structure and the distribution of LIKE HETEROCHROMATIN PROTEIN1 were affected, indicating epigenetic perturbations. In summary, the MMC transcriptome sets the stage for future functional characterization as illustrated by the identification of MEM, a novel gene involved in the restriction of germline fate.
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Affiliation(s)
- Anja Schmidt
- Institute of Plant Biology & Zürich-Basel Plant Science Center, University of Zürich, Zürich, Switzerland
| | - Samuel E. Wuest
- Institute of Plant Biology & Zürich-Basel Plant Science Center, University of Zürich, Zürich, Switzerland
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Kitty Vijverberg
- Institute of Plant Biology & Zürich-Basel Plant Science Center, University of Zürich, Zürich, Switzerland
| | - Célia Baroux
- Institute of Plant Biology & Zürich-Basel Plant Science Center, University of Zürich, Zürich, Switzerland
| | - Daniela Kleen
- Institute of Plant Biology & Zürich-Basel Plant Science Center, University of Zürich, Zürich, Switzerland
| | - Ueli Grossniklaus
- Institute of Plant Biology & Zürich-Basel Plant Science Center, University of Zürich, Zürich, Switzerland
- * E-mail:
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Ueda M, Matsui K, Ishiguro S, Kato T, Tabata S, Kobayashi M, Seki M, Shinozaki K, Okada K. Arabidopsis RPT2a encoding the 26S proteasome subunit is required for various aspects of root meristem maintenance, and regulates gametogenesis redundantly with its homolog, RPT2b. PLANT & CELL PHYSIOLOGY 2011; 52:1628-40. [PMID: 21784786 DOI: 10.1093/pcp/pcr093] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The 26S proteasome plays fundamental roles in the degradation of short-lived regulatory proteins, thereby controlling diverse cellular processes. In Arabidopsis, the essential RPT2 subunit is encoded by two highly homologous genes: RPT2a and RPT2b. Currently, only RPT2a has been reported to regulate various developmental processes, including the maintenance of the root apical meristem (RAM), although the roles of RPT2a in the RAM are still obscure. Here, we analyzed the cell type-specific requirement for RPT2a. When RPT2a was expressed locally in the rpt2a mutant, pleiotropic defects in the RAM, such as cell death and distorted cellular organization, were rescued differently, suggesting that RPT2a regulates various specific activities, which converge to maintain the RAM. On the other hand, the homologous RPT2b was also expressed in meristems, and the expression of RPT2b protein under the control of the RPT2a promoter complemented the rpt2a RAM defects, although the rpt2b mutant showed no obvious defect in all developmental aspects we examined. These results show that RPT2b might work in the RAM, but is dispensable for RAM maintenance in the presence of RPT2a. In contrast, the rpt2a rpt2b double mutant was lethal in male and female gametophytes, suggesting that RPT2a and RPT2b are redundantly required for gametogenesis. Furthermore, we showed that similar meristematic and gametophytic defects were caused by mutations in other subunit genes, RPT5a and RPT5b, suggesting that proper activity of the proteasome, not an RPT2-specific function, is required. Taken together, our results suggest that RPT2a and RPT2b contribute differently to the proteasome activity required for each developmental context.
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Affiliation(s)
- Minako Ueda
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, Japan
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Complex genetic nature of sex-independent transmission ratio distortion in Asian rice species: the involvement of unlinked modifiers and sex-specific mechanisms. Heredity (Edinb) 2011; 108:242-7. [PMID: 21792227 DOI: 10.1038/hdy.2011.64] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Transmission ratio distortion (TRD), in which one allele is transmitted more frequently than the opposite allele, is presumed to act as a driving force in the emergence of a reproductive barrier. TRD acting in a sex-specific manner has been frequently observed in interspecific and intraspecific hybrids across a broad range of organisms. In contrast, sex-independent TRD (siTRD), which results from preferential transmission of one of the two alleles in the heterozygote through both sexes, has been detected in only a few plant species. We previously reported an S(6) locus-mediated siTRD, in which the S(6) allele from an Asian wild rice strain (Oryza rufipogon) was transmitted more frequently than the S(6)(a) allele from an Asian cultivated rice strain (O. sativa) through both male and female gametes in heterozygous plants. Here, we report on the effect of a difference in genetic background on S(6) locus-mediated siTRD, based on the analysis using near-isogenic lines and the original wild strain as a parental strain for crossing. We found that the degree of TRD through the male gametes varied depending on the genetic background of the female (pistil) plants. Despite the occurrence of TRD through both male and female gametes, abnormality was detected in ovules, but not in pollen grains, in the heterozygote. These results suggest the involvement of unlinked modifiers and developmentally distinct, sex-specific genetic mechanisms in S(6) locus-mediated siTRD, raising the possibility that siTRD driven by a single locus may be affected by multiple genetic factors harbored in natural populations.
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Rodrigo-Peiris T, Xu XM, Zhao Q, Wang HJ, Meier I. RanGAP is required for post-meiotic mitosis in female gametophyte development in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:2705-14. [PMID: 21282324 DOI: 10.1093/jxb/erq448] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
RanGAP is the GTPase-activating protein of the small GTPase Ran and is involved in nucleocytoplasmic transport in yeast and animals via the Ran cycle and in mitotic cell division. Arabidopsis thaliana has two copies of RanGAP, RanGAP1 and RanGAP2. To investigate the function of plant RanGAP, T-DNA insertional mutants were analysed. Arabidopsis plants with a null mutant of either RanGAP1 or RanGAP2 had no observable phenotype. Analysis of segregating progeny showed that double mutants in RanGAP1 and RanGAP2 are female gametophyte defective. Ovule clearing with differential interference contrast optics showed that mutant female gametophytes were arrested at interphase, predominantly after the first mitotic division following meiosis. In contrast, mutant pollen developed and functioned normally. These results show that the two RanGAPs are redundant and indispensable for female gametophyte development in Arabidopsis but dispensable for pollen development. Nuclear division arrest during a mitotic stage suggests a role for plant RanGAP in mitotic cell cycle progression during female gametophyte development.
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Affiliation(s)
- Thushani Rodrigo-Peiris
- Department of Plant Cellular and Molecular Biology, The Ohio State University, Columbus, OH 43210, USA
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Arabidopsis thaliana MIRO1 and MIRO2 GTPases are unequally redundant in pollen tube growth and fusion of polar nuclei during female gametogenesis. PLoS One 2011; 6:e18530. [PMID: 21494602 PMCID: PMC3073945 DOI: 10.1371/journal.pone.0018530] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 03/09/2011] [Indexed: 12/23/2022] Open
Abstract
MIRO GTPases have evolved to regulate mitochondrial trafficking and morphology in eukaryotic organisms. A previous study showed that T-DNA insertion in the Arabidopsis MIRO1 gene is lethal during embryogenesis and affects pollen tube growth and mitochondrial morphology in pollen, whereas T-DNA insertion in MIRO2 does not affect plant development visibly. Phylogenetic analysis of MIRO from plants revealed that MIRO 1 and 2 orthologs in dicots cluster in two separate groups due to a gene/genome duplication event, suggesting that functional redundancy may exists between the two MIRO genes. To investigate this possibility, we generated miro1(+/−)/miro2-2(−/−) plants. Compared to miro1(+/−)plants, the miro1(+/−)/miro2-2(−/−) plants showed increased segregation distortion. miro1(+/−)/miro2-2(−/−) siliques contained less aborted seeds, but more than 3 times the number of undeveloped ovules. In addition, reciprocal crosses showed that co-transmission through the male gametes was nearly absent, whereas co-transmission through the female gametes was severely reduced in miro1(+/−)/miro2-2(−/−) plants. Further investigations revealed that loss of MIRO2 (miro2(−/−)) function in the miro1(+/−) background enhanced pollen tube growth defects. In developing miro1(+/−)/miro2(−/−) embryo sacs, fusion of polar nuclei was further delayed or impaired compared to miro1 plants. This phenotype has not been reported previously for miro1 plants and coincides with studies showing that defects in some mitochondria-targeted genes results in the same phenotype. Our observations show that loss of function in MIRO2 in a miro1(+/−) background enhances the miro1(+/−) phenotype significantly, even though miro2(−/−) plants alone does not display any phenotypes. Based on these findings, we conclude that MIRO1 and MIRO2 are unequally redundant and that a proportion of the miro1(+/−)/miro2(−/−) plants haploid gametes displays the complete null phenotype of MIRO GTPase function at key developmental stages.
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Cross talk between the sporophyte and the megagametophyte during ovule development. ACTA ACUST UNITED AC 2011; 24:113-21. [PMID: 21298290 DOI: 10.1007/s00497-011-0162-3] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 01/19/2011] [Indexed: 10/18/2022]
Abstract
In seed plant ovules, the diploid maternal sporophytic generation embeds and sustains the haploid generation (the female gametophyte); thus, two independent generations coexist in a single organ. Many independent studies on Arabidopsis ovule mutants suggest that embryo sac development requires highly synchronized morphogenesis of the maternal sporophyte surrounding the gametophyte, since megagametogenesis is severely perturbed in most of the known sporophytic ovule development mutants. Which are the messenger molecules involved in the haploid-diploid dialogue? And furthermore, is this one way communication or is a feedback cross talk? In this review, we discuss genetic and molecular evidences supporting the presence of a cross talk between the two generations, starting from the first studies regarding ovule development and ending to the recently sporophytic identified genes whose expression is strictly controlled by the haploid gametophytic generation. We will mainly focus on Arabidopsis studies since it is the species more widely studied for this aspect. Furthermore, possible candidate molecules involved in the diploid-haploid generations dialogue will be presented and discussed.
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Abstract
The angiosperm female gametophyte is critical for plant reproduction. It contains the egg cell and central cell that become fertilized and give rise to the embryo and endosperm of the seed, respectively. Female gametophyte development begins early in ovule development with the formation of a diploid megaspore mother cell that undergoes meiosis. One resulting haploid megaspore then develops into the female gametophyte. Genetic and epigenetic processes mediate specification of megaspore mother cell identity and limit megaspore mother cell formation to a single cell per ovule. Auxin gradients influence female gametophyte polarity and a battery of transcription factors mediate female gametophyte cell specification and differentiation. The mature female gametophyte secretes peptides that guide the pollen tube to the embryo sac and contains protein complexes that prevent seed development before fertilization. Post-fertilization, the female gametophyte influences seed development through maternal-effect genes and by regulating parental contributions. Female gametophytes can form by an asexual process called gametophytic apomixis, which involves formation of a diploid female gametophyte and fertilization-independent development of the egg into the embryo. These functions collectively underscore the important role of the female gametophyte in seed and food production.
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Affiliation(s)
- Gary N. Drews
- Department of Biology, University of Utah, Salt Lake City, UT 84112
- Address correspondence to
| | - Anna M.G Koltunow
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Waite Campus, South Australia 5064, Australia
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Ingram GC. Family life at close quarters: communication and constraint in angiosperm seed development. PROTOPLASMA 2010; 247:195-214. [PMID: 20661606 DOI: 10.1007/s00709-010-0184-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 07/12/2010] [Indexed: 05/05/2023]
Abstract
The formation of viable angiosperm seeds involves the co-ordinated growth and development of three genetically distinct organisms, the maternally derived seed coat and the zygotic embryo and endosperm. The physical relationships of these tissues are initially established during the specification and differentiation of the female gametophyte within the tissues of the developing ovule. The molecular programmes implicated in both ovule and seed development involve elements of globally important pathways (such as auxin signalling), as well as ovule- and seed-specific pathways. Recurrent themes, such as the precisely controlled death of specific cell types and the regulation of cell-cell communication and nutrition by the selective establishment of symplastic and apoplastic barriers, appear to play key roles in both pre- and post-fertilization seed development. Much of post-fertilization seed growth occurs during a key developmental window shortly after fertilization and involves the dramatic expansion of the young endosperm, constrained by surrounding maternal tissues. The complex tissue-specific regulation of carbohydrate metabolism in specific seed compartments has been shown to provide a driving force for this early seed expansion. The embryo, which is arguably the most important component of the seed, appears to be only minimally involved in early seed development. Given the evolutionary and agronomic importance of angiosperm seeds, the complex combination of communication pathways which co-ordinate their growth and development remains remarkably poorly understood.
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Liu M, Shi DQ, Yuan L, Liu J, Yang WC. SLOW WALKER3, encoding a putative DEAD-box RNA helicase, is essential for female gametogenesis in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2010; 52:817-28. [PMID: 20738726 DOI: 10.1111/j.1744-7909.2010.00972.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
RNA helicases are adenosine tri-phosphatases that unwind the secondary structures of RNAs and are required in almost any aspect of RNA metabolism. They are highly conserved from prokaryotic to eukaryotic organisms. However, their precise roles in plant physiology and development remain to be clarified. Here we report that the mutation in the gene SLOW WALKER3 (SWA3) results in the slow and retarded progression of mitosis during megagametogenesis in Arabidopsis. SWA3 is a putative RNA helicase of the DEAD-box subfamily. Mutant megagametophyte development is arrested at four- or eight-nucleate stages, furthermore, one of the synergids in about half of the mutant embryo sacs displays abnormal polarity, with its nucleus locating at the chalazal end, instead of the micropylar end in the wild-type. Transmission of the mutation through female gametophytes is severely reduced in swa3. However, a small portion of mutant embryo sacs are able to develop into mature and functional female gametophytes when pollination was postponed. The SWA3 in Arabidopsis is a homolog of Dbp8 in yeast. Dbp8 interacts with Efs2 and is essential for biogenesis of 18S rRNA in yeast. Our data suggest that SWA3 may form a complex with AtEfs2 and take roles in ribosomal biogenesis as RNA helicase during megagametogenesis in Arabidopsis.
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Affiliation(s)
- Man Liu
- Key Laboratory of Molecular and Developmental Biology, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing, China
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Li HJ, Liu NY, Shi DQ, Liu J, Yang WC. YAO is a nucleolar WD40-repeat protein critical for embryogenesis and gametogenesis in Arabidopsis. BMC PLANT BIOLOGY 2010; 10:169. [PMID: 20699009 PMCID: PMC3095302 DOI: 10.1186/1471-2229-10-169] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Accepted: 08/11/2010] [Indexed: 05/18/2023]
Abstract
BACKGROUND In flowering plants, gametogenesis generates multicellular male and female gametophytes. In the model system Arabidopsis, the male gametophyte or pollen grain contains two sperm cells and a vegetative cell. The female gametophyte or embryo sac contains seven cells, namely one egg, two synergids, one central cell and three antipodal cells. Double fertilization of the central cell and egg produces respectively a triploid endosperm and a diploid zygote that develops further into an embryo. The genetic control of the early embryo patterning, especially the initiation of the first zygotic division and the positioning of the cell plate, is largely unknown. RESULTS Here we report the characterization of a mutation, yaozhe (yao), that causes zygote arrest and misplacement of cell plate of the zygote, leading to early embryo lethality. In addition, gametophyte development is partially impaired. A small portion of the mutant embryo sacs are arrested at four-nucleate stage with aberrant nuclear positioning. Furthermore, the competence of male gametophytes is also compromised. YAO encodes a nucleolar protein with seven WD-repeats. Its homologues in human and yeast have been shown to be components of the U3 snoRNP complex and function in 18S rRNA processing. YAO is expressed ubiquitously, with high level of expression in tissues under active cell divisions, including embryo sacs, pollen, embryos, endosperms and root tips. CONCLUSIONS Phenotypic analysis indicated that YAO is required for the correct positioning of the first zygotic division plane and plays a critical role in gametogenesis in Arabidopsis. Since YAO is a nucleolar protein and its counterparts in yeast and human are components of the U3 snoRNP complex, we therefore postulate that YAO is most likely involved in rRNA processing in plants as well.
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Affiliation(s)
- Hong-Ju Li
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
- Gradute University, the Chinese Academy of Sciences, Beijing 100049, China
| | - Nai-You Liu
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
| | - Dong-Qiao Shi
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
| | - Jie Liu
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
| | - Wei-Cai Yang
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
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Tan XY, Liu XL, Wang W, Jia DJ, Chen LQ, Zhang XQ, Ye D. Mutations in the Arabidopsis nuclear-encoded mitochondrial phage-type RNA polymerase gene RPOTm led to defects in pollen tube growth, female gametogenesis and embryogenesis. PLANT & CELL PHYSIOLOGY 2010; 51:635-49. [PMID: 20231244 DOI: 10.1093/pcp/pcq029] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The mitochondrial genes in Arabidopsis thaliana are transcribed by a small family of nuclear-encoded T3/T7 phage-type RNA polymerases (RPOTs). At least two nuclear-encoded RPOTs (RPOTm and RPOTmp) are located in mitochondria in A. thaliana. Their genetic roles are largely unknown. Here we report the characterization of novel mutations in the A. thaliana RPOTm gene. The mutations did not affect pollen formation, but significantly retarded the growth of the rpoTm mutant pollen tubes and had an impact on the fusion of the polar nuclei in the rpoTm mutant embryo sacs. Moreover, development of the rpoTm/- mutant embryo was arrested at the globular stage. The rpoTm rpoTmp double mutation could enhance the rpoTm mutant phenotype. Expression of RPOTmp under control of the RPOTm promoter could not complement the phenotype of the rpoTm mutations. All these data indicate that RPOTm is important for normal pollen tube growth, female gametogenesis and embryo development, and has distinct genetic and molecular roles in plant development, which cannot be replaced by RPOTmp.
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Affiliation(s)
- Xiao-Yun Tan
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
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