1
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Cowling CL, Dash L, Kelley DR. Roles of auxin pathways in maize biology. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:6989-6999. [PMID: 37493143 PMCID: PMC10690729 DOI: 10.1093/jxb/erad297] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 07/24/2023] [Indexed: 07/27/2023]
Abstract
Phytohormones play a central role in plant development and environmental responses. Auxin is a classical hormone that is required for organ formation, tissue patterning, and defense responses. Auxin pathways have been extensively studied across numerous land plant lineages, including bryophytes and eudicots. In contrast, our understanding of the roles of auxin in maize morphogenesis and immune responses is limited. Here, we review evidence for auxin-mediated processes in maize and describe promising areas for future research in the auxin field. Several recent transcriptomic and genetic studies have demonstrated that auxin is a key influencer of both vegetative and reproductive development in maize (namely roots, leaves, and kernels). Auxin signaling has been implicated in both maize shoot architecture and immune responses through genetic and molecular analyses of the conserved co-repressor RAMOSA ENHANCER LOCUS2. Polar auxin transport is linked to maize drought responses, root growth, shoot formation, and leaf morphogenesis. Notably, maize has been a key system for delineating auxin biosynthetic pathways and offers many opportunities for future investigations on auxin metabolism. In addition, crosstalk between auxin and other phytohormones has been uncovered through gene expression studies and is important for leaf and root development in maize. Collectively these studies point to auxin as a cornerstone for maize biology that could be leveraged for improved crop resilience and yield.
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Affiliation(s)
- Craig L Cowling
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011, USA
| | - Linkan Dash
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011, USA
| | - Dior R Kelley
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011, USA
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2
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Chettoor AM, Yang B, Evans MMS. Control of cellularization, nuclear localization, and antipodal cell cluster development in maize embryo sacs. Genetics 2023; 225:iyad101. [PMID: 37232380 DOI: 10.1093/genetics/iyad101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 03/30/2023] [Accepted: 05/15/2023] [Indexed: 05/27/2023] Open
Abstract
The maize female gametophyte contains four cell types: two synergids, an egg cell, a central cell, and a variable number of antipodal cells. In maize, these cells are produced after three rounds of free-nuclear divisions followed by cellularization, differentiation, and proliferation of the antipodal cells. Cellularization of the eight-nucleate syncytium produces seven cells with two polar nuclei in the central cell. Nuclear localization is tightly controlled in the embryo sac. This leads to precise allocation of the nuclei into the cells upon cellularization. Nuclear positioning within the syncytium is highly correlated with their identity after cellularization. Two mutants are described with extra polar nuclei, abnormal antipodal cell morphology, and reduced antipodal cell number, as well as frequent loss of antipodal cell marker expression. Mutations in one of these genes, indeterminate gametophyte2 encoding a MICROTUBULE ASSOCIATED PROTEIN65-3 homolog, shows a requirement for MAP65-3 in cellularization of the syncytial embryo sac as well as for normal seed development. The timing of the effects of ig2 suggests that the identity of the nuclei in the syncytial female gametophyte can be changed very late before cellularization.
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Affiliation(s)
- Antony M Chettoor
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Bing Yang
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
- Division of Plant Science and Technology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Matthew M S Evans
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
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3
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Robil JM, McSteen P. Hormonal control of medial-lateral growth and vein formation in the maize leaf. THE NEW PHYTOLOGIST 2023; 238:125-141. [PMID: 36404129 DOI: 10.1111/nph.18625] [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: 04/15/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
Parallel veins are characteristic of monocots, including grasses (Poaceae). Therefore, how parallel veins develop as the leaf grows in the medial-lateral (ML) dimension is a key question in grass leaf development. Using fluorescent protein reporters, we mapped auxin, cytokinin (CK), and gibberellic acid (GA) response patterns in maize (Zea mays) leaf primordia. We further defined the roles of these hormones in ML growth and vein formation through combinatorial genetic analyses and measurement of hormone concentrations. We discovered a novel pattern of auxin response in the adaxial protoderm that we hypothesize has important implications for the orderly formation of 3° veins early in leaf development. In addition, we found an auxin transport and response pattern in the margins that correlate with the transition from ML to proximal-distal growth. We present evidence that auxin efflux precedes CK response in procambial strand development. We also determined that GA plays an early role in the shoot apical meristem as well as a later role in the primordium to restrict ML growth. We propose an integrative model whereby auxin regulates ML growth and vein formation in the maize leaf through control of GA and CK.
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Affiliation(s)
- Janlo M Robil
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri, Columbia, MO, 65211, USA
- Department of Biology, School of Science and Engineering, Ateneo de Manila University, Loyola Heights, Quezon City, Metro Manila, 1108, Philippines
| | - Paula McSteen
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri, Columbia, MO, 65211, USA
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4
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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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5
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Doronina TV, Ashapkin VV, Lazareva EM. Wheat Antipodal Cells with Polytene Chromosomes in the Embryo Sac Are Key to Understanding the Formation of Grain in Cereals. BIOLOGY 2022; 11:biology11091340. [PMID: 36138819 PMCID: PMC9495325 DOI: 10.3390/biology11091340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/07/2022] [Accepted: 09/09/2022] [Indexed: 11/27/2022]
Abstract
Simple Summary The present work is devoted to the features of antipodal cells at the early stages of wheat seed development, ensuring the formation and protection of a full-fledged grain. Using the methods of cell and molecular biology, changes in the structure of these cells and their components during active functioning and death are shown. For the first time, data on the expression of some genes confirming the functions of antipodal cells were obtained. The characteristic features of cells at the stages of death were revealed. The data obtained indicate the key role of antipodal cells in the process of grain maturation and subsequently allow us to identify substances that ensure the formation of tissue, which is the food of the whole world. Abstract The ultrastructure of antipodal cells of the Triticum aestivum embryo sac was studied at different stages of differentiation and programmed cell death. The importance of cell function in the antipodal complex is evidenced by the fact that it is fully formed before double fertilization, past the stages of proliferation of three initial cells, and several rounds of genome endoreduplication during differentiation. In this study, we showed that the actively synthesizing organelles, the granular reticulum, and Golgi apparatus, alter their structure during differentiation and death. The polymorphism of the shape of the mitochondria and plastids was demonstrated. For the first time, the actin filaments of the cytoskeleton and numerous multivesicular bodies associated with the plasma membrane were detected in the cytoplasm. The transfer of cytoplasm and organelles between antipodal cells and into the coenocyte of the endosperm was confirmed. DNA breaks and the release of cytochrome c at various stages of death were revealed. To understand the function of the antipodal cells, a quantitative PCR analysis of the expression of wheat genes involved in protective, antistress, and metabolic processes was carried out. We found that gene expression in the antipodal cell fraction was increased compared with that in the whole embryo sac. On the basis of the data, we assume that antipodal cells produce both nutrients and numerous antistress factors that ensure the normal development of the endosperm of the grain, which, in turn, further ensures the development of the embryo.
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Affiliation(s)
- Tatiana V. Doronina
- Biology Faculty, Lomonosov Moscow State University, Moscow 119234, Russia
- Correspondence:
| | - Vasily V. Ashapkin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Elena M. Lazareva
- Biology Faculty, Lomonosov Moscow State University, Moscow 119234, Russia
- All-Russia Research Institute for Agricultural Biotechnology, Moscow 119234, Russia
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6
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Tang S, Shahriari M, Xiang J, Pasternak T, Igolkina A, Aminizade S, Zhi H, Gao Y, Roodbarkelari F, Sui Y, Jia G, Wu C, Zhang L, Zhao L, Li X, Meshcheryakov G, Samsonova M, Diao X, Palme K, Teale W. The role of AUX1 during lateral root development in the domestication of the model C4 grass Setaria italica. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2021-2034. [PMID: 34940828 DOI: 10.1093/jxb/erab556] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
C4 photosynthesis increases the efficiency of carbon fixation by spatially separating high concentrations of molecular oxygen from Rubisco. The specialized leaf anatomy required for this separation evolved independently many times. The morphology of C4 root systems is also distinctive and adapted to support high rates of photosynthesis; however, little is known about the molecular mechanisms that have driven the evolution of C4 root system architecture. Using a mutant screen in the C4 model plant Setaria italica, we identify Siaux1-1 and Siaux1-2 as root system architecture mutants. Unlike in S. viridis, AUX1 promotes lateral root development in S. italica. A cell by cell analysis of the Siaux1-1 root apical meristem revealed changes in the distribution of cell volumes in all cell layers and a dependence of the frequency of protophloem and protoxylem strands on SiAUX1. We explore the molecular basis of the role of SiAUX1 in seedling development using an RNAseq analysis of wild-type and Siaux1-1 plants and present novel targets for SiAUX1-dependent gene regulation. Using a selection sweep and haplotype analysis of SiAUX1, we show that Hap-2412TT in the promoter region of SiAUX1 is an allele which is associated with lateral root number and has been strongly selected for during Setaria domestication.
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Affiliation(s)
- Sha Tang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Mojgan Shahriari
- Institute of Biology II, University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
| | - Jishan Xiang
- Academy of Agricultural Sciences/Key Laboratory of Regional Ecological Protection & Agricultural and Animal Husbandry Development, Chifeng University, Chifeng, 024000, Inner Mongolia, China
| | - Taras Pasternak
- Institute of Biology II, University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
| | - Anna Igolkina
- Department of Computational Biology, Center for Advanced Studies, St. Petersburg State Polytechnic University, St. Petersburg, 195259, Russia
| | | | - Hui Zhi
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Yuanzhu Gao
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Farshad Roodbarkelari
- Institute of Biology III, University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
| | - Yi Sui
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Guanqing Jia
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Chuanyin Wu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Linlin Zhang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Lirong Zhao
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Xugang Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai'an, 271018, China
| | - Georgy Meshcheryakov
- Department of Computational Biology, Center for Advanced Studies, St. Petersburg State Polytechnic University, St. Petersburg, 195259, Russia
| | - Maria Samsonova
- Department of Computational Biology, Center for Advanced Studies, St. Petersburg State Polytechnic University, St. Petersburg, 195259, Russia
| | - Xianmin Diao
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Klaus Palme
- Institute of Biology II, University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
- Centre of Biological Systems Analysis and BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104 Freiburg, Germany
| | - William Teale
- Institute of Biology II, University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
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7
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Doronina TV, Lazareva EM. Structure of antipodal cells nuclei of wheat embryo sac during programmed cell death. PLANTA 2021; 254:48. [PMID: 34379202 DOI: 10.1007/s00425-021-03701-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 08/04/2021] [Indexed: 06/13/2023]
Abstract
During antipodal cells PCD, polytene chromosomes rearrangement, segregation of nucleoli components and extrusion of nuclear components occur, cytochrome c is released from the mitochondria and DNA breaks appear. We studied in detail the nuclei of cells of the antipodal complex of wheat embryo sac (Triticum aestivum L.) during programmed cell death (PCD). The antipodal complex has been reported to be formed before double fertilisation of the embryo sac. Polyploidisation leads to the formation of giant polytene chromosomes in the nuclei of antipodal cells. These chromosomes are involved in secretory functions and are important for the development of cellular endosperm. Terminal deoxynucleotidyl transferase dUTP nick end labelling assay and immunodetection revealed DNA breaks in the nuclei and release of cytochrome c from mitochondria into the cytoplasm of antipodal cells during PCD. We used transmission electron microscopy, immunodetection and histochemistry to analyse the characteristic structural changes in the nuclei of antipodal cells during PCD. These included sequential structural changes in the nuclei containing polytene chromosomes, segregation of some components of the nucleolus into the bodies of polytene chromosomes, extrusion of nucleolar components and parts of chromosomes into the cytoplasm of antipodal cells and then into the endosperm coenocyte. The obtained results expand the understanding of the structural changes of plant cells with giant polytene chromosomes during PCD.
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Affiliation(s)
- T V Doronina
- Biology Faculty, Lomonosov Moscow State University, Leninskie Gory, 1, Building 12, Moscow, 119992, Russia.
| | - E M Lazareva
- Biology Faculty, Lomonosov Moscow State University, Leninskie Gory, 1, Building 12, Moscow, 119992, Russia
- All-Russia Research Institute for Agricultural Biotechnology, Moscow, 127550, Russia
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8
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Wei H, Cheng Y, Sun Y, Zhang X, He H, Liu J. Genome-Wide Identification of the ARF Gene Family and ARF3 Target Genes Regulating Ovary Initiation in Hazel via ChIP Sequencing. FRONTIERS IN PLANT SCIENCE 2021; 12:715820. [PMID: 34447403 PMCID: PMC8382943 DOI: 10.3389/fpls.2021.715820] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/14/2021] [Indexed: 06/13/2023]
Abstract
Hazel (Corylus spp.) is an economically important nut species with a unique biological characteristic of ovary differentiation and development initiating from the ovary primordium after pollination. Auxin participates in ovary initiation and has an essential impact on hazel fruit yield and quality. The regulation of auxin in ovary development is thought to be related to auxin response factors (ARFs); however, its detailed regulatory mechanism remains unclear. The spatiotemporal expression pattern of C. heterophylla ARF3 (ChARF3) was accessed via ARF gene family member identification and expression abundance analysis as well as immunohistochemistry. ChARF3 target genes were identified via chromatin immunoprecipitation followed by next-generation sequencing (ChIP-Seq). In total, 14 ChARF members containing at least B3 and Auxin_resp domains were found to be distributed on 9 of 11 chromosomes, and the protein molecular weights were predicted to range from 70.93-139.22 kD. Among eight differentially expressed ChARFs, ChARF3 showed the most significant differences over four ovary developmental stages. Immunohistochemical analysis revealed that ChARF3 was expressed in the ovary primordium and funiculus, integument, endosperm, radicle, and cotyledon indicating its potential regulatory roles in ovary differentiation and development. In total, 3,167 ChARF3 target genes were identified through ChIP-Seq in four ovary developmental stages and were significantly enriched in the biosynthesis of secondary metabolites (ko01110), phenylpropanoid biosynthesis (ko00940), and phytohormone signal transduction (ko04075). ChARF3 was hypothesized to be involved in the regulation of auxin-induced genes and the transcription factors MADS, AP2/ERF, TCP, FT, and LFY. These results suggest that ChARF3 may regulate ovary initiation and ovule development by mediating genes related to auxin biosynthesis and transport, cell division and proliferation, and flower and fruit development. This study provides new insights into the molecular mechanism of hazel yield formation.
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Affiliation(s)
| | | | | | | | | | - Jianfeng Liu
- Jilin Provincial Key Laboratory of Plant Resource Science and Green Production, Jilin Normal University, Siping, China
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9
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Rudall PJ. Evolution and patterning of the ovule in seed plants. Biol Rev Camb Philos Soc 2021; 96:943-960. [PMID: 33432779 DOI: 10.1111/brv.12684] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/23/2020] [Accepted: 01/04/2021] [Indexed: 02/06/2023]
Abstract
The ovule and its developmental successor, the seed, together represent a highly characteristic feature of seed plants that has strongly enhanced the reproductive and dispersal potential of this diverse group of taxa. Ovules encompass multiple tissues that perform various roles within a highly constrained space, requiring a complex cascade of genes that generate localized cell proliferation and programmed cell death during different developmental stages. Many heritable morphological differences among lineages reflect relative displacement of these tissues, but others, such as the second (outer) integuments of angiosperms and Gnetales, represent novel and apparently profound and independent innovations. Recent studies, mostly on model taxa, have considerably enhanced our understanding of gene expression in the ovule. However, understanding its evolutionary history requires a comparative and phylogenetic approach that is problematic when comparing extant angiosperms not only with phylogenetically distant extant gymnosperms but also with taxa known only from fossils. This paper reviews ovule characters across a phylogenetically broad range of seed plants in a dynamic developmental context. It discusses both well-established and recent theories of ovule and seed evolution and highlights potential gaps in comparative data that will usefully enhance our understanding of evolutionary transitions and developmental mechanisms.
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Affiliation(s)
- Paula J Rudall
- Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, U.K
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10
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Hater F, Nakel T, Groß-Hardt R. Reproductive Multitasking: The Female Gametophyte. ANNUAL REVIEW OF PLANT BIOLOGY 2020; 71:517-546. [PMID: 32442389 DOI: 10.1146/annurev-arplant-081519-035943] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Fertilization of flowering plants requires the organization of complex tasks, many of which become integrated by the female gametophyte (FG). The FG is a few-celled haploid structure that orchestrates division of labor to coordinate successful interaction with the sperm cells and their transport vehicle, the pollen tube. As reproductive outcome is directly coupled to evolutionary success, the underlying mechanisms are under robust molecular control, including integrity check and repair mechanisms. Here, we review progress on understanding the development and function of the FG, starting with the functional megaspore, which represents the haploid founder cell of the FG. We highlight recent achievements that have greatly advanced our understanding of pollen tube attraction strategies and the mechanisms that regulate plant hybridization and gamete fusion. In addition, we discuss novel insights into plant polyploidization strategies that expand current concepts on the evolution of flowering plants.
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Affiliation(s)
- Friederike Hater
- Centre for Biomolecular Interactions, University of Bremen, 28359 Bremen, Germany;
| | - Thomas Nakel
- Centre for Biomolecular Interactions, University of Bremen, 28359 Bremen, Germany;
| | - Rita Groß-Hardt
- Centre for Biomolecular Interactions, University of Bremen, 28359 Bremen, Germany;
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11
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Zhao H, Guo M, Yan M, Cheng H, Liu Y, She Z, Lai L, Shi C, Zhang M, Li Y, Lin D, Qin Y. Comparative Expression Profiling Reveals Genes Involved in Megasporogenesis. PLANT PHYSIOLOGY 2020; 182:2006-2024. [PMID: 32054780 PMCID: PMC7140934 DOI: 10.1104/pp.19.01254] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 02/02/2020] [Indexed: 05/21/2023]
Abstract
Megasporogenesis is a key step during ovule development in angiosperms, but the small number and inaccessibility of these cells have hampered molecular and genome-wide studies. Thus, many questions remain regarding the molecular basis of cell specification, differentiation, and development in the female gametophyte. Here, taking advantage of the correlation between spikelet length and ovule development in rice (Oryza sativa), we studied the transcriptome dynamics of young ovules at three stages, the archesporial cell, the megaspore mother cell before meiosis, and the functional megaspore after meiosis, using expression profiling based on RNA sequencing. Our analysis showed that 5,274 genes were preferentially expressed in ovules during megasporogenesis as compared to ovules at the mature female gametophyte stage. Out of these, 958 (18.16%) genes were archesporial cell- and/or megaspore mother cell-preferential genes, and represent a significant enrichment of genes involved in hormone signal transduction and plant pathogen interaction pathways, as well as genes encoding transcription factors. The expression patterns of nine genes that were preferentially expressed in ovules of different developmental stages, including the OsERECTA2 (OsER2) receptor-like kinase gene, were confirmed by in situ hybridization. We further characterized the OsER2 loss-of-function mutant, which had an excessive number of female germline cells and an abnormal female gametophyte, suggesting that OsER2 regulates germline cell specification during megasporogenesis in rice. These results expand our understanding of the molecular control of megasporogenesis in rice and contribute to the functional studies of genes involved in megasporogenesis.
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Affiliation(s)
- Heming Zhao
- Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Mingliang Guo
- Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Maokai Yan
- Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning 530004, Guangxi, China
| | - Han Cheng
- Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yanhui Liu
- Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zeyuan She
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning 530004, Guangxi, China
| | - Linyi Lai
- Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Chao Shi
- Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Minqian Zhang
- Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yi Li
- Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Deshu Lin
- Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yuan Qin
- Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning 530004, Guangxi, China
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12
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Imaging of Embryo Sac and Early Seed Development in Maize after Feulgen Staining. Methods Mol Biol 2020; 2122:191-203. [PMID: 31975304 DOI: 10.1007/978-1-0716-0342-0_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
Abstract
Compared with small model plants like Arabidopsis containing ovules with few cell layers, embryo sac and embryo development of model crop plants such as maize and other grasses are difficult to image. Multiple layers of tissue usually surround the deeply embedded embryo sac and developing embryo. Moreover, reliable cell biological marker lines labeling, for example, nuclei, plasma membrane, cell walls, or cells of a specific identity are often not available. The introduction of markers to study mutants is difficult and time-consuming and may require several generations of backcrosses. In this chapter, we therefore present an easy protocol to image maize ovaries and developing embryo sacs before and after fertilization allowing also high-throughput mutant analysis. The laborious embedding of samples and preparation of thin sections are omitted in this fixing-Feulgen staining-clearing (FFC) method. Optical sectioning through multiple layers of tissue is possible allowing 3D reconstructions of the whole embryo sac if necessary. The advantage of staining cell nuclei using the FFC method described here compared, for example, with DAPI staining is a wide range of Schiff's type reagents available for the Feulgen reaction. Depending on the reagent of choice, various conditions such as different excitation/emission filters or even white light can be applied for imaging. Moreover, in order to better visualize cell division, nuclei polarity as well as cell extent and integrity, periodic acid staining (PAS) of cell walls can be combined with Feulgen staining.
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13
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Abstract
The plant haploid generation is specified late in higher plant development, and post-meiotic haploid plant cells divide mitotically to produce a haploid gametophyte, in which a subset of cells differentiates into the gametes. The immediate mother of the angiosperm seed is the female gametophyte, also called the embryo sac. In most flowering plants the embryo sac is comprised of two kinds of gametes (egg and central cell) and two kinds of subsidiary cells (antipodals and synergids) all of which descend from a single haploid spore produced by meiosis. The embryo sac develops within a specialized organ of the flower called the ovule, which supports and controls many steps in the development of both the embryo sac and the seed. Double fertilization of the central cell and egg cell by the two sperm cells of a pollen grain produce the endosperm and embryo of the seed, respectively. The endosperm and embryo develop under the influence of their precursor gametes and the surrounding tissues of the ovule and the gametophyte. The final size and pattern of the angiosperm seed then is the result of complex interactions across multiple tissues of three different generations (maternal sporophyte, maternal gametophyte, and the fertilization products) and three different ploidies (haploid gametophyte, diploid parental sporophyte and embryo, and triploid endosperm).
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14
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Brzezicka E, Kozieradzka-Kiszkurno M. Female gametophyte development in Sedum sediforme (Jacq.) Pau (Crassulaceae): an anatomical, cytochemical and ultrastructural analysis. PROTOPLASMA 2019; 256:537-553. [PMID: 30324403 PMCID: PMC6514081 DOI: 10.1007/s00709-018-1319-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/04/2018] [Indexed: 06/08/2023]
Abstract
Available documentation about the development of the female gametophyte of Crassulaceae is very limited. The aim of this study was to extend the embryological knowledge of Crassulaceae by analysing the development of the embryo sac in Sedum sediforme. Transmission electron microscopy and light microscopy including Nomarski optics (DIC) were used to observe individual stages of female gametophyte development. Cytochemical staining enabled detection of lipids, insoluble polysaccharides and proteins in gametophyte cells during their formation. Their increased accumulation was observed during nucellar cell and unfunctional cell degeneration in the embryo sac at the coenocytic and cellular stages (megagametogenesis). The female gametophyte develops in anatropous, bitegmic and crassinucellate ovules. The mature embryo sac is built of seven cells but after antipodes degeneration it is formed by the egg apparatus and a central cell. The monosporic Polygonum type was observed. One megaspore mother cell (MMC) formed three cells after meiosis. A triad was formed from a functional megaspore (placed chalazally), one uninucleate megaspore and a binucleate cell located at the micropylar end. Plasmodesmata with adhering electron-dense dome were noticed in walls of the coenocytic embryo sac and in the outer walls of ephemeral antipodes. Moreover, similar to synergids, antipodes form wall ingrowths. Here, we report new structural features of the antipodal cells (the presence of plasmodesmata with an electron-dense dome) which have not been described before. This new structural observation indicates that these cells participate in substance transport and that this process can probably be additionally regulated.
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Affiliation(s)
- Emilia Brzezicka
- Department of Plant Cytology and Embryology, Faculty of Biology, University of Gdańsk, 59 Wita Stwosza St., 80-308, Gdańsk, Poland
| | - Małgorzata Kozieradzka-Kiszkurno
- Department of Plant Cytology and Embryology, Faculty of Biology, University of Gdańsk, 59 Wita Stwosza St., 80-308, Gdańsk, Poland.
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15
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Shirley NJ, Aubert MK, Wilkinson LG, Bird DC, Lora J, Yang X, Tucker MR. Translating auxin responses into ovules, seeds and yield: Insight from Arabidopsis and the cereals. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2019; 61:310-336. [PMID: 30474296 DOI: 10.1111/jipb.12747] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 11/16/2018] [Indexed: 05/27/2023]
Abstract
Grain production in cereal crops depends on the stable formation of male and female gametes in the flower. In most angiosperms, the female gamete is produced from a germline located deep within the ovary, protected by several layers of maternal tissue, including the ovary wall, ovule integuments and nucellus. In the field, germline formation and floret fertility are major determinants of yield potential, contributing to traits such as seed number, weight and size. As such, stimuli affecting the timing and duration of reproductive phases, as well as the viability, size and number of cells within reproductive organs can significantly impact yield. One key stimulant is the phytohormone auxin, which influences growth and morphogenesis of female tissues during gynoecium development, gametophyte formation, and endosperm cellularization. In this review we consider the role of the auxin signaling pathway during ovule and seed development, first in the context of Arabidopsis and then in the cereals. We summarize the gene families involved and highlight distinct expression patterns that suggest a range of roles in reproductive cell specification and fate. This is discussed in terms of seed production and how targeted modification of different tissues might facilitate improvements.
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Affiliation(s)
- Neil J Shirley
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - Matthew K Aubert
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - Laura G Wilkinson
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - Dayton C Bird
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - Jorge Lora
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - Xiujuan Yang
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - Matthew R Tucker
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
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16
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Erbasol Serbes I, Palovaara J, Groß-Hardt R. Development and function of the flowering plant female gametophyte. Curr Top Dev Biol 2019; 131:401-434. [DOI: 10.1016/bs.ctdb.2018.11.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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17
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Abstract
The haploid female gametophyte (embryo sac) is an essential reproductive unit of flowering plants, usually comprising four specialized cell types, including the female gametes (egg cell and central cell). The differentiation of these cells relies on spatial signals which pattern the gametophyte along a proximal-distal axis, but the molecular and genetic mechanisms by which cell identities are determined in the embryo sac have long been a mystery. Recent identification of key genes for cell fate specification and their relationship to hormonal signaling pathways that act on positional cues has provided new insights into these processes. A model for differentiation can be devised with egg cell fate as a default state of the female gametophyte and with other cell types specified by the action of spatially regulated factors. Cell-to-cell communication within the gametophyte is also important for maintaining cell identity as well as facilitating fertilization of the female gametes by the male gametes (sperm cells).
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Affiliation(s)
- Debra J Skinner
- Department of Plant Biology, University of California-Davis, Davis, USA
| | - Venkatesan Sundaresan
- Department of Plant Biology, University of California-Davis, Davis, USA.,Department of Plant Sciences, University of California-Davis, Davis, USA
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18
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Live-Cell Imaging of Auxin and Cytokinin Signaling in Maize Female Gametophytes. Methods Mol Biol 2017; 1669:95-101. [PMID: 28936653 DOI: 10.1007/978-1-4939-7286-9_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
The plant life cycle is characterized by the alternation of generations between genetically active diploid sporophytes and haploid gametophytes. The gametophytes of flowering plants are sexually dimorphic. While the male gametophyte consists of only three cells (two sperm and a vegetative cell) and is released by the parent sporophyte, the female gametophyte (or embryo sac) is more complex and remains imbedded within diploid sporophyte tissues. In maize, the female gametophyte is embedded in a large ovule surrounded with multiple nucellar cell layers impeding live-cell imaging approaches to study embryo sac functions. Here, we describe a simple protocol to visualize embryo sacs with hormonal fluorescent reporters by increasing accessibility of the female gametophyte. The method described is applicable for visualization of any fluorescent embryo sac reporter. The embryo sacs visualization method developed for maize could be extended to facilitate visualization of embryos sac in other important cereals like wheat, rice, and oats.
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19
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Huang X, Peng X, Sun MX. OsGCD1 is essential for rice fertility and required for embryo dorsal-ventral pattern formation and endosperm development. THE NEW PHYTOLOGIST 2017; 215:1039-1058. [PMID: 28585692 DOI: 10.1111/nph.14625] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 04/25/2017] [Indexed: 05/20/2023]
Abstract
Rice fertility is critical for rice reproduction and is thus a focus of interest. Most studies have addressed male sterility and its relation to rice production. The mechanisms of regulation of embryogenesis and endosperm development are essential for rice reproduction, but remain largely unknown. Here, we report a functional analysis of the rice gene OsGCD1, which encodes a highly conserved homolog of Arabidopsis GCD1 (GAMETE CELLS DEFECTIVE1). OsGCD1 mutants were generated using the CRISPR/Cas9 system and subjected to functional analysis. The homozygote mutants cannot be obtained, whereas heterozygotes showed altered phenotypes. In the majority of aborted seeds, the endosperm nucleus divided a limited number of times. The free nuclei were distributed only at the micropylar end of embryo sacs, and their oriented positioning was blocked. In addition, aleurone differentiation was interrupted. The embryo developed slowly, and pattern formation, particularly the dorsal-ventral pattern and symmetry establishment, of embryos was disturbed. Thus, the embryos showed various morphological and structural dysplasias. Our findings reveal that OsGCD1 is essential for rice fertility and is required for dorsal-ventral pattern formation and endosperm free nucleus positioning, suggesting a critical role in sexual reproduction of both monocotyledon and dicotyledon plants.
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Affiliation(s)
- Xiaorong Huang
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Xiongbo Peng
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Meng-Xiang Sun
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
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20
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Ingram GC. Dying to live: cell elimination as a developmental strategy in angiosperm seeds. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:785-796. [PMID: 27702990 DOI: 10.1093/jxb/erw364] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The complete elimination of unwanted cells during development is a repeated theme in both multicellular animals and in plants. In plants, such events have been extensively studied and reviewed in terms of their molecular regulation, of marker genes and proteins expressed, and in terms of cellular changes associated with their progression. This review will take a slightly different view of developmental cell elimination and will concentrate specifically on the numerous elimination events that occur during ovule and seed development (here grouped together as seed development). It asks why this cell elimination occurs in specific seed tissues, in order to understand something about the commonalities underlying how seemingly disparate events are triggered and regulated. Finally, by placing the seed in its broader evolutionary context, the question of why cell elimination may have emerged as such a key component of the seed developmental toolbox will be considered.
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Affiliation(s)
- Gwyneth C Ingram
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, CNRS (UMR 5667), INRA (UMR 0879), UCB Lyon 1, Ecole Normale Supérieure de Lyon, F-69342 Lyon, France
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21
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Yang L, Wu Y, Yu M, Mao B, Zhao B, Wang J. Genome-wide transcriptome analysis of female-sterile rice ovule shed light on its abortive mechanism. PLANTA 2016; 244:1011-1028. [PMID: 27357232 DOI: 10.1007/s00425-016-2563-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 06/23/2016] [Indexed: 05/03/2023]
Abstract
The comprehensive transcriptome analysis of rice female-sterile line and wild-type line ovule provides an important clue for exploring the regulatory network of the formation of rice fertile female gametophyte. Ovules are the female reproductive tissues of rice (Oryza sativa L.) and play a major role in sexual reproduction. To investigate the potential mechanism of rice female gametophyte fertility, we used RNA sequencing, combined with genetic subtraction, to compare the transcriptome of the ovules of a high-frequency female-sterile line (fsv1) and a rice wild-type line (Gui 99) during ovule development. Ovules were harvested at three developmental stages: ovule containing megaspore mother cell in meiosis process (stage 1), ovule containing functional megaspore in mitosis process (stage 2), and ovule containing mature female gametophyte (stage 3). Six cDNA libraries generated a total of 42.2 million high-quality clean reads that aligned with 30,204 genes. The comparison between the fsv1 and Gui 99 ovules identified a large number of differentially expressed genes (DEGs), i.e., 45, 495, and 932 DEGs at the three ovule developmental stages, respectively. From the comparison of the two rice lines, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and MapMan analyses indicated that a large number of DEGs associated with starch and sucrose metabolism, plant hormone signal transduction, protein modification and degradation, oxidative phosphorylation, and receptor kinase. These DEGs might play roles in ovule development and fertile female gametophyte formation. Many transcription factor genes and epigenetic-related genes also exhibit different expression patterns and significantly different expression levels in two rice lines during ovule development, which might provide important information regarding the abortive mechanism of the female gametophyte in rice.
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Affiliation(s)
- Liyu Yang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Ya Wu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Meiling Yu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Bigang Mao
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, 410125, China
| | - Bingran Zhao
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, 410125, China.
| | - Jianbo Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
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22
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Hands P, Rabiger DS, Koltunow A. Mechanisms of endosperm initiation. PLANT REPRODUCTION 2016; 29:215-25. [PMID: 27450467 PMCID: PMC4978757 DOI: 10.1007/s00497-016-0290-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 07/14/2016] [Indexed: 05/21/2023]
Abstract
KEY MESSAGE Overview of developmental events and signalling during central cell maturation and early endosperm development with a focus on mechanisms of sexual and autonomous endosperm initiation. Endosperm is important for seed viability and global food supply. The mechanisms regulating the developmental transition between Female Gametophyte (FG) maturation and early endosperm development in angiosperms are difficult to study as they occur buried deep within the ovule. Knowledge of the molecular events underlying this developmental window of events has significantly increased with the combined use of mutants, cell specific markers, and plant hormone sensing reporters. Here, we review recent discoveries concerning the developmental events and signalling of FG maturation, fertilization, and endosperm development. We focus on the regulation of the initiation of endosperm development with and without fertilization in Arabidopsis and the apomict Hieracium, comparing this to what is known in monocots where distinct differences in developmental patterning may underlie alternative mechanisms of suppression and initiation. The Polycomb Repressive Complex 2 (PRC2), plant hormones, and transcription factors are iteratively involved in early fertilization-induced endosperm formation in Arabidopsis. Auxin increases and PRC2 complex inactivation can also induce fertilization-independent endosperm proliferation in Arabidopsis. Function of the PRC2 complex member FERTILIZATION-INDEPENDENT ENDOSPERM and two loci AutE and LOP are required for autonomous endosperm development in apomictic Hieracium. A comparative understanding of cues required for early endosperm development will facilitate genetic engineering approaches for the development of resilient seed crops, especially if an option for fertilization-independent endosperm formation was possible to combat stress-induced crop failure.
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Affiliation(s)
- Philip Hands
- CSIRO Agriculture and Food, Commonwealth Scientific and Industrial Research Organization, Private Bag 2, Glen Osmond, SA, 5064, Australia
| | - David S Rabiger
- CSIRO Agriculture and Food, Commonwealth Scientific and Industrial Research Organization, Private Bag 2, Glen Osmond, SA, 5064, Australia
| | - Anna Koltunow
- CSIRO Agriculture and Food, Commonwealth Scientific and Industrial Research Organization, Private Bag 2, Glen Osmond, SA, 5064, Australia.
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23
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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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24
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Cheng F, Lu J, Gao M, Shi K, Kong Q, Huang Y, Bie Z. Redox Signaling and CBF-Responsive Pathway Are Involved in Salicylic Acid-Improved Photosynthesis and Growth under Chilling Stress in Watermelon. FRONTIERS IN PLANT SCIENCE 2016; 7:1519. [PMID: 27777580 PMCID: PMC5056192 DOI: 10.3389/fpls.2016.01519] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/26/2016] [Indexed: 05/18/2023]
Abstract
Salicylic acid (SA) plays an important role in plant response to abiotic stresses. This study investigated the potential role of SA in alleviating the adverse effects of chilling stress on photosynthesis and growth in watermelon (Citrullus lanatus). Chilling stress induced the simultaneous accumulation of free and conjugated SA in watermelon plants, and the chilling-induced SA production was attributed to the phenylalanine ammonia-lyase pathway. Applying SA at moderate concentrations induced chilling tolerance, whereas inhibition of SA biosynthesis by L-α-aminooxy-β-phenylpropionic acid (AOPP) increased the photooxidation of PS II under chilling stress in watermelon, resulting in reduced photosynthesis and growth. Chilling induced a transient increase in the ratios of reduced to oxidized glutathione and reduced ascorbate to dehydroascorbate. Then, the expression of antioxidant genes was upregulated, and the activities of antioxidant enzymes were enhanced. Furthermore, SA-induced chilling tolerance was associated with cellular glutathione and ascorbate homeostasis, which served as redox signals to regulate antioxidant metabolism under chilling stress. AOPP treatment stimulated the chilling-induced expression of cold-responsive genes, particularly via C-repeat binding factors CBF3 and CBF4. These results confirm the synergistic role of SA signaling and the CBF-dependent responsive pathway during chilling stress in watermelon.
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Affiliation(s)
- Fei Cheng
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural UniversityWuhan, China
| | - Junyang Lu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural UniversityWuhan, China
| | - Min Gao
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural UniversityWuhan, China
| | - Kai Shi
- Department of Horticulture, Zhejiang UniversityHangzhou, China
| | - Qiusheng Kong
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural UniversityWuhan, China
| | - Yuan Huang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural UniversityWuhan, China
| | - Zhilong Bie
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural UniversityWuhan, China
- *Correspondence: Zhilong Bie,
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25
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Cheng F, Lu J, Gao M, Shi K, Kong Q, Huang Y, Bie Z. Redox Signaling and CBF-Responsive Pathway Are Involved in Salicylic Acid-Improved Photosynthesis and Growth under Chilling Stress in Watermelon. FRONTIERS IN PLANT SCIENCE 2016. [PMID: 27777580 DOI: 10.3389/fpls.2016.0151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Salicylic acid (SA) plays an important role in plant response to abiotic stresses. This study investigated the potential role of SA in alleviating the adverse effects of chilling stress on photosynthesis and growth in watermelon (Citrullus lanatus). Chilling stress induced the simultaneous accumulation of free and conjugated SA in watermelon plants, and the chilling-induced SA production was attributed to the phenylalanine ammonia-lyase pathway. Applying SA at moderate concentrations induced chilling tolerance, whereas inhibition of SA biosynthesis by L-α-aminooxy-β-phenylpropionic acid (AOPP) increased the photooxidation of PS II under chilling stress in watermelon, resulting in reduced photosynthesis and growth. Chilling induced a transient increase in the ratios of reduced to oxidized glutathione and reduced ascorbate to dehydroascorbate. Then, the expression of antioxidant genes was upregulated, and the activities of antioxidant enzymes were enhanced. Furthermore, SA-induced chilling tolerance was associated with cellular glutathione and ascorbate homeostasis, which served as redox signals to regulate antioxidant metabolism under chilling stress. AOPP treatment stimulated the chilling-induced expression of cold-responsive genes, particularly via C-repeat binding factors CBF3 and CBF4. These results confirm the synergistic role of SA signaling and the CBF-dependent responsive pathway during chilling stress in watermelon.
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Affiliation(s)
- Fei Cheng
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China
| | - Junyang Lu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China
| | - Min Gao
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China
| | - Kai Shi
- Department of Horticulture, Zhejiang University Hangzhou, China
| | - Qiusheng Kong
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China
| | - Yuan Huang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China
| | - Zhilong Bie
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China
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26
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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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