1
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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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2
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Rojek J, Ohad N. The phenomenon of autonomous endosperm in sexual and apomictic plants. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4324-4348. [PMID: 37155961 PMCID: PMC10433939 DOI: 10.1093/jxb/erad168] [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: 01/18/2023] [Accepted: 05/04/2023] [Indexed: 05/10/2023]
Abstract
Endosperm is a key nutritive tissue that supports the developing embryo or seedling, and serves as a major nutritional source for human and livestock feed. In sexually-reproducing flowering plants, it generally develops after fertilization. However, autonomous endosperm (AE) formation (i.e. independent of fertilization) is also possible. Recent findings of AE loci/ genes and aberrant imprinting in native apomicts, together with a successful initiation of parthenogenesis in rice and lettuce, have enhanced our understanding of the mechanisms bridging sexual and apomictic seed formation. However, the mechanisms driving AE development are not well understood. This review presents novel aspects related to AE development in sexual and asexual plants underlying stress conditions as the primary trigger for AE. Both application of hormones to unfertilized ovules and mutations that impair epigenetic regulation lead to AE development in sexual Arabidopsis thaliana, which may point to a common pathway for both phenomena. Apomictic-like AE development under experimental conditions can take place due to auxin-dependent gene expression and/or DNA methylation.
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Affiliation(s)
- Joanna Rojek
- Department of Plant Cytology and Embryology, Faculty of Biology, University of Gdansk, Gdansk, Poland
| | - Nir Ohad
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
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3
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Shin JM, Yuan L, Kawashima T. Live-cell imaging reveals the cellular dynamics in seed development. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 325:111485. [PMID: 36206961 DOI: 10.1016/j.plantsci.2022.111485] [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: 05/06/2022] [Revised: 09/28/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Seed development in flowering plants is highly complex and governed by three genetically distinct tissues: the fertilization products, the diploid embryo and triploid endosperm, as well as the seed coat that has maternal origin. There are diverse cellular dynamics such as nuclear movement in gamete cells for fertilization, cell polarity establishment for embryo development, and multinuclear endosperm formation. These tissues also coordinate and synchronize the developmental timing for proper seed formation through cell-to-cell communications. Live-cell imaging using advanced microscopy techniques enables us to decipher the dynamics of these events. Especially, the establishment of a less-invasive semi-in vivo live-cell imaging approach has allowed us to perform time-lapse analyses for long period observation of Arabidopsis thaliana intact seed development dynamics. Here we highlight the recent trends of live-cell imaging for seed development and discuss where we are heading.
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Affiliation(s)
- Ji Min Shin
- Department of Plant and Soil Sciences, University of Kentucky, KY, USA; Kentucky Tobacco Research and Development Center, University of Kentucky, KY, USA
| | - Ling Yuan
- Department of Plant and Soil Sciences, University of Kentucky, KY, USA; Kentucky Tobacco Research and Development Center, University of Kentucky, KY, USA
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4
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Zheng Y. Molecular mechanisms of maize endosperm transfer cell development. PLANT CELL REPORTS 2022; 41:1171-1180. [PMID: 34689216 DOI: 10.1007/s00299-021-02807-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/14/2021] [Indexed: 05/12/2023]
Abstract
Endosperm transfer cells function as the nutrient transporter, antimicrobic barrier, and signal mediator between filial and maternal tissues. Sugar supply of maternal tissues, sugar demand of filial tissues, and requirement for defence against pathogens are three elemental factors inducing differentiation of endosperm transfer cells. Epigenetic factors, especially MEG1, moderate the key genetic factor ZmMRP-1 to activate endosperm transfer cell-specific genes that control the flange wall ingrowth formation and defensin-like protein secretion in maize. Auxin and cytokinin are primary hormones involved in development of maize endosperm transfer cells. Crosstalk between glucose and hormone signaling regulates endosperm transfer cell development via modifying ZmMRP-1 expression. This review summarizes the current knowledge on maize endosperm transfer cell development, and discusses its potential molecular mechanisms. It is expected to strengthen the theoretical basis for structural and functional optimization of endosperm transfer cells, and yield improvement of kernels in maize.
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Affiliation(s)
- Yankun Zheng
- School of Life Sciences, Anqing Normal University, Anqing, 246133, Anhui, China.
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5
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Wu H, Becraft PW, Dannenhoffer JM. Maize Endosperm Development: Tissues, Cells, Molecular Regulation and Grain Quality Improvement. FRONTIERS IN PLANT SCIENCE 2022; 13:852082. [PMID: 35330868 PMCID: PMC8940253 DOI: 10.3389/fpls.2022.852082] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 02/11/2022] [Indexed: 05/12/2023]
Abstract
Maize endosperm plays important roles in human diet, animal feed and industrial applications. Knowing the mechanisms that regulate maize endosperm development could facilitate the improvement of grain quality. This review provides a detailed account of maize endosperm development at the cellular and histological levels. It features the stages of early development as well as developmental patterns of the various individual tissues and cell types. It then covers molecular genetics, gene expression networks, and current understanding of key regulators as they affect the development of each tissue. The article then briefly considers key changes that have occurred in endosperm development during maize domestication. Finally, it considers prospects for how knowledge of the regulation of endosperm development could be utilized to enhance maize grain quality to improve agronomic performance, nutrition and economic value.
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Affiliation(s)
- Hao Wu
- Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, United States
| | - Philip W. Becraft
- Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, United States
- *Correspondence: Philip W. Becraft,
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6
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Gu W, Yu D, Guan Y, Wang H, Qin T, Sun P, Hu Y, Wei J, Zheng H. The dynamic transcriptome of waxy maize (Zea mays L. sinensis Kulesh) during seed development. Genes Genomics 2020; 42:997-1010. [PMID: 32676852 DOI: 10.1007/s13258-020-00967-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/03/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND Waxy maize (Zea mays L. sinensis Kulesh) is a mutant of maize (Zea mays L.) with a mutation at Waxy1 (Wx1) gene locus. The seed of waxy maize has higher viscosity compared to regular maize. By now, we know little about the expression patterns of genes that involved in the seed development of waxy maize. OBJECTIVE By analyzing the transcriptome data during waxy maize seed development, we attempt to dig out the genes that may influence the seed development of waxy maize. METHODS The seeds of waxy maize inbred line SWL01 from six phases after pollination were used to do RNA-seq. Bioinformatics methods were used to analyze the expression patterns of the expressed genes, to identify the genes involved in waxy maize seed development. RESULTS A total of 24,546 genes including 1611 transcription factors (TFs) were detected during waxy maize seed development. Coexpression analysis of expressed genes revealed the dynamic processes of waxy maize seed development. Particularly, 2457 genes including 177 TFs were specially expressed in waxy maize seed, some of which mainly involved in the process of seed dormancy and maturation. In addition, 2681, 5686, 4491, 4386, 3669 and 4624 genes were identified to be differential expressed genes (DEGs) at six phases compared to regular maize B73, and 113 DEGs among them may be key genes that lead the difference of seed development between waxy and regular maizes in milk stage. CONCLUSION In summary, we elucidated the expression patterns of expressed genes during waxy maize seed development globally. A series of genes that associated with seed development were identified in our research, which may provide an important resource for functional study of waxy maize seed development to help molecular assisted breeding.
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Affiliation(s)
- Wei Gu
- Crop Breeding and Cultivation Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.,CIMMYT-China Specialty Maize Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China
| | - Diansi Yu
- Crop Breeding and Cultivation Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.,CIMMYT-China Specialty Maize Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China
| | - Yuan Guan
- Crop Breeding and Cultivation Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.,CIMMYT-China Specialty Maize Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China
| | - Hui Wang
- Crop Breeding and Cultivation Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.,CIMMYT-China Specialty Maize Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China
| | - Tao Qin
- Crop Breeding and Cultivation Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.,CIMMYT-China Specialty Maize Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China
| | - Pingdong Sun
- Crop Breeding and Cultivation Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.,CIMMYT-China Specialty Maize Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China
| | - Yingxiong Hu
- Crop Breeding and Cultivation Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.,CIMMYT-China Specialty Maize Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China
| | - Jihui Wei
- Crop Breeding and Cultivation Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.,CIMMYT-China Specialty Maize Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China
| | - Hongjian Zheng
- Crop Breeding and Cultivation Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China. .,CIMMYT-China Specialty Maize Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.
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7
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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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8
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Qu Y, Wu P, Ren J, Liu Z, Tang J, Lübberstedt T, Li H, Chen S. Mapping of QTL for kernel abortion caused by in vivo haploid induction in maize (Zea mays L.). PLoS One 2020; 15:e0228411. [PMID: 32023320 PMCID: PMC7001950 DOI: 10.1371/journal.pone.0228411] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 01/14/2020] [Indexed: 01/01/2023] Open
Abstract
Kernel abortion is common phenomenon in vivo haploid induction and closely linked with haploid induction rate, but little information of kernel abortion is available and its genetic basis still unclear. We used two mapping populations including 186 and 263 F2.3 family lines to analyze the different degree of kernel abortion and identify quantitative trait loci (QTL) responsible for kernel abortion during haploid induction. In total 62 putative QTL, accounting for 3.27-14.70% of the phenotypic variation in kernel abortion traits, were detected across all 10 chromosomes. Ten QTL with over 10% contribution to phenotypic variation were affecting the fifth level of endosperm abortion (EnA5th), endosperm abortion (EnA) and total abortion (TA). Co-localization among kernel abortion traits QTL was observed in both populations and among different kernel abortion types. Five overlaps were indentified in the QTL for kernel abortion traits and HIR traits. Maize chromosome bins 3.01-3.02, 3.04-3.06, 4.05-4.06, 5.03-5.04, 8.06 were QTL hotspots for three or four traits related to the kernel abortion during haploid induction. Total kernel abortion rate (TAR) and HIR showed highly significant positive correlation. These findings may help to reveal haploid induction mechanisms and improve haploid production efficiency.
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Affiliation(s)
- Yanzhi Qu
- College of Agronomy, National Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou, China
| | - Penghao Wu
- National Maize Improvement Center, China Agricultural University, Beijing, China
- College of Agronomy, Xinjiang Agricultural University, Urumuqi, China
| | - Jiaojiao Ren
- National Maize Improvement Center, China Agricultural University, Beijing, China
- College of Agronomy, Xinjiang Agricultural University, Urumuqi, China
| | - Zonghua Liu
- College of Agronomy, National Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou, China
| | - Jihua Tang
- College of Agronomy, National Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou, China
| | - Thomas Lübberstedt
- Department of Agronomy, Iowa State University, Ames, Iowa, United States of America
| | - Haochuan Li
- College of Agronomy, National Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou, China
- National Maize Improvement Center, China Agricultural University, Beijing, China
- * E-mail: (HL); (SC)
| | - Shaojiang Chen
- National Maize Improvement Center, China Agricultural University, Beijing, China
- * E-mail: (HL); (SC)
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9
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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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10
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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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11
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Bai F, Corll J, Shodja DN, Davenport R, Feng G, Mudunkothge J, Brigolin CJ, Martin F, Spielbauer G, Tseung CW, Siebert AE, Barbazuk WB, Lal S, Settles AM. RNA Binding Motif Protein 48 Is Required for U12 Splicing and Maize Endosperm Differentiation. THE PLANT CELL 2019; 31:715-733. [PMID: 30760564 PMCID: PMC6482629 DOI: 10.1105/tpc.18.00754] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/11/2019] [Accepted: 02/13/2019] [Indexed: 05/19/2023]
Abstract
The last eukaryotic common ancestor had two classes of introns that are still found in most eukaryotic lineages. Common U2-type and rare U12-type introns are spliced by the major and minor spliceosomes, respectively. Relatively few splicing factors have been shown to be specific to the minor spliceosome. We found that the maize (Zea mays) RNA binding motif protein 48 (RBM48) is a U12 splicing factor that functions to promote cell differentiation and repress cell proliferation. RBM48 is coselected with the U12 splicing factor, zinc finger CCCH-type, RNA binding motif, and Ser/Arg rich 2/Rough endosperm 3 (RGH3). Protein-protein interactions between RBM48, RGH3, and U2 Auxiliary Factor (U2AF) subunits suggest major and minor spliceosome factors required for intron recognition form complexes with RBM48. Human RBM48 interacts with armadillo repeat containing 7 (ARMC7). Maize RBM48 and ARMC7 have a conserved protein-protein interaction. These data predict that RBM48 is likely to function in U12 splicing throughout eukaryotes and that U12 splicing promotes endosperm cell differentiation in maize.
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Affiliation(s)
- Fang Bai
- Horticultural Sciences Department, and Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611
| | - Jacob Corll
- Department of Biological Sciences, Oakland University, Rochester, Michigan 48309
| | - Donya N Shodja
- Department of Biological Sciences, Oakland University, Rochester, Michigan 48309
| | - Ruth Davenport
- Department of Biology and Genetics Institute, University of Florida, Gainesville, Florida 32611
| | - Guanqiao Feng
- Department of Biology and Genetics Institute, University of Florida, Gainesville, Florida 32611
| | - Janaki Mudunkothge
- Horticultural Sciences Department, and Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611
| | - Christian J Brigolin
- Department of Biological Sciences, Oakland University, Rochester, Michigan 48309
| | - Federico Martin
- Horticultural Sciences Department, and Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611
| | - Gertraud Spielbauer
- Horticultural Sciences Department, and Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611
| | - Chi-Wah Tseung
- Horticultural Sciences Department, and Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611
| | - Amy E Siebert
- Department of Biological Sciences, Oakland University, Rochester, Michigan 48309
| | - W Brad Barbazuk
- Department of Biology and Genetics Institute, University of Florida, Gainesville, Florida 32611
| | - Shailesh Lal
- Department of Biological Sciences, Oakland University, Rochester, Michigan 48309
| | - A Mark Settles
- Horticultural Sciences Department, and Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611
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12
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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: 22] [Impact Index Per Article: 3.1] [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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13
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Li J, Fu J, Chen Y, Fan K, He C, Zhang Z, Li L, Liu Y, Zheng J, Ren D, Wang G. The U6 Biogenesis-Like 1 Plays an Important Role in Maize Kernel and Seedling Development by Affecting the 3' End Processing of U6 snRNA. MOLECULAR PLANT 2017; 10:470-482. [PMID: 27825944 DOI: 10.1016/j.molp.2016.10.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 10/29/2016] [Accepted: 10/30/2016] [Indexed: 05/09/2023]
Abstract
Regulation of gene expression at the post-transcriptional level is of crucial importance in the development of an organism. Here we present the characterization of a maize gene, U6 biogenesis-like 1 (UBL1), which plays an important role in kernel and seedling development by influencing pre-mRNA splicing. The ubl1 mutant, exhibiting small kernel and weak seedling, was isolated from a Mutator-tagged population. Transgenic complementation and three independent mutant alleles confirmed that UBL1, which encodes a putative RNA exonuclease belonging to the 2H phosphodiesterase superfamily, is responsible for the phenotype of ubl1. We demonstrated that UBL1 possess the RNA exonuclease activity in vitro and found that loss of UBL1 function in ubl1 causes decreased level and abnormal 3' end constitution of snRNA U6, resulting in splicing defect of mRNAs. Through the in vitro and in vivo studies replacing two histidines with alanines in the H-X-T/S-X (X is a hydrophobic residue) motifs we demonstrated that these two motifs are essential for the normal function of UBL1. We further showed that the function of UBL1 may be conserved across a wide phylogenetic distance as the heterologous expression of maize UBL1 could complement the Arabidopsis ubl1 mutant.
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Affiliation(s)
- Jiankun Li
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China; State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences
| | - Junjie Fu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yan Chen
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Kaijian Fan
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Cheng He
- Center of Seed Science and Technology, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China
| | - Zhiqiang Zhang
- Center of Seed Science and Technology, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China
| | - Li Li
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yunjun Liu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jun Zheng
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Dongtao Ren
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences
| | - Guoying Wang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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14
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Zhou LZ, Juranić M, Dresselhaus T. Germline Development and Fertilization Mechanisms in Maize. MOLECULAR PLANT 2017; 10:389-401. [PMID: 28267957 DOI: 10.1016/j.molp.2017.01.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 01/29/2017] [Accepted: 01/31/2017] [Indexed: 05/06/2023]
Abstract
Maize is the most important agricultural crop used for food, feed, and biofuel as well as a raw material for industrial products such as packaging material. To increase yield and to overcome hybridization barriers, studies of maize gamete development, the pollen tube journey, and fertilization mechanisms were initiated more than a century ago. In this review, we summarize and discuss our current understanding of the regulatory components for germline development including sporogenesis and gametogenesis, the progamic phase of pollen germination and pollen tube growth and guidance, as well as fertilization mechanisms consisting of pollen tube arrival and reception, sperm cell release, fusion with the female gametes, and egg cell activation. Mechanisms of asexual seed development are not considered here. While only a few molecular players involved in these processes have been described to date and the underlying mechanisms are far from being understood, maize now represents a spearhead of reproductive research for all grass species. Recent development of essentially improved transformation and gene-editing systems may boost research in this area in the near future.
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Affiliation(s)
- Liang-Zi Zhou
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Martina Juranić
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.
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15
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Yang M, Gao X, Dong J, Gandhi N, Cai H, von Wettstein DH, Rustgi S, Wen S. Pattern of Protein Expression in Developing Wheat Grains Identified through Proteomic Analysis. FRONTIERS IN PLANT SCIENCE 2017; 8:962. [PMID: 28649254 PMCID: PMC5465268 DOI: 10.3389/fpls.2017.00962] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Accepted: 05/22/2017] [Indexed: 05/20/2023]
Abstract
Grain development is one of the biological processes, which contributes to the final grain yield. To understand the molecular changes taking place during the early grain development, we profiled proteomes of two common wheat cultivars P271 and Chinese Spring (CS) with large and small grains, respectively at three grain developmental stages (4, 8, and 12 days post anthesis). An iTRAQ (isobaric tags for relative and absolute quantitation) based proteomics approach was used for this purpose. More than 3,600 proteins were reported to accumulate during early grain development in both wheat cultivars. Of these 3,600 proteins, 130 expressed differentially between two wheat cultivars, and 306 exhibited developmental stage-specific accumulation in either or both genotypes. Detailed bioinformatic analyses of differentially expressed proteins (DEPs) from the large- and small-grain wheat cultivars underscored the developmental differences observed between them and shed light on the molecular and cellular processes contributing to these differences. In silico localization of either or both sets of DEPs to wheat chromosomes exhibited a biased genomic distribution with chromosome 4D contributing largely to it. These results corresponded well with the earlier studies, performed in common wheat, where chromosome 4D was reported to harbor QTLs for yield contributing traits specifically grain length. Collectively, our results provide insight into the molecular processes taking place during early grain development, a knowledge, which may prove useful in improving wheat grain yield in the future.
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Affiliation(s)
- Mingming Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F UniversityYangling, China
- Wheat Engineering Research Center of Shaanxi Province, Northwest A&F UniversityYangling, China
| | - Xiang Gao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F UniversityYangling, China
- Wheat Engineering Research Center of Shaanxi Province, Northwest A&F UniversityYangling, China
- *Correspondence: Xiang Gao
| | - Jian Dong
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F UniversityYangling, China
- Wheat Engineering Research Center of Shaanxi Province, Northwest A&F UniversityYangling, China
| | - Nitant Gandhi
- Department of Plant and Environmental Sciences, Clemson University Pee Dee Research and Education CenterFlorence, SC, United States
| | - Huanjie Cai
- Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F UniversityYangling, China
- Institute of Water Saving Agriculture in Arid Regions of China, Northwest A&F UniversityYangling, China
| | - Diter H. von Wettstein
- Department of Crop and Soil Sciences, Washington State UniversityPullman, WA, United States
| | - Sachin Rustgi
- Department of Plant and Environmental Sciences, Clemson University Pee Dee Research and Education CenterFlorence, SC, United States
- Department of Crop and Soil Sciences, Washington State UniversityPullman, WA, United States
- Sachin Rustgi
| | - Shanshan Wen
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F UniversityYangling, China
- Shanshan Wen
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16
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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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17
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Parent-of-Origin-Effect rough endosperm Mutants in Maize. Genetics 2016; 204:221-31. [PMID: 27440865 DOI: 10.1534/genetics.116.191775] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/12/2016] [Indexed: 01/06/2023] Open
Abstract
Parent-of-origin-effect loci have non-Mendelian inheritance in which phenotypes are determined by either the maternal or paternal allele alone. In angiosperms, parent-of-origin effects can be caused by loci required for gametophyte development or by imprinted genes needed for seed development. Few parent-of-origin-effect loci have been identified in maize (Zea mays) even though there are a large number of imprinted genes known from transcriptomics. We screened rough endosperm (rgh) mutants for parent-of-origin effects using reciprocal crosses with inbred parents. Six maternal rough endosperm (mre) and three paternal rough endosperm (pre) mutants were identified with three mre loci mapped. When inherited from the female parent, mre/+ seeds reduce grain fill with a rough, etched, or pitted endosperm surface. Pollen transmission of pre mutants results in rgh endosperm as well as embryo lethality. Eight of the mutants had significant distortion from the expected one-to-one ratio for parent-of-origin effects. Linked markers for mre1, mre2, and mre3 indicated that the mutant alleles have no bias in transmission. Histological analysis of mre1, mre2, mre3, and pre*-949 showed altered timing of starch grain accumulation and basal endosperm transfer cell layer (BETL) development. The mre1 locus delays BETL and starchy endosperm development, while mre2 and pre*-949 cause ectopic starchy endosperm differentiation. We conclude that many parent-of-origin effects in maize have incomplete penetrance of kernel phenotypes and that there is a large diversity of endosperm developmental roles for parent-of-origin-effect loci.
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Yang H, Liu X, Xin M, Du J, Hu Z, Peng H, Rossi V, Sun Q, Ni Z, Yao Y. Genome-Wide Mapping of Targets of Maize Histone Deacetylase HDA101 Reveals Its Function and Regulatory Mechanism during Seed Development. THE PLANT CELL 2016; 28:629-45. [PMID: 26908760 PMCID: PMC4826005 DOI: 10.1105/tpc.15.00691] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 02/21/2016] [Indexed: 05/03/2023]
Abstract
Histone deacetylases (HDACs) regulate histone acetylation levels by removing the acetyl group from lysine residues. The maize (Zea mays) HDACHDA101 influences several aspects of development, including kernel size; however, the molecular mechanism by which HDA101 affects kernel development remains unknown. In this study, we find that HDA101 regulates the expression of transfer cell-specific genes, suggesting that their misregulation may be associated with the defects in differentiation of endosperm transfer cells and smaller kernels observed in hda101 mutants. To investigate HDA101 function during the early stages of seed development, we performed genome-wide mapping of HDA101 binding sites. We observed that, like mammalian HDACs, HDA101 mainly targets highly and intermediately expressed genes. Although loss of HDA101 can induce histone hyperacetylation of its direct targets, this often does not involve variation in transcript levels. A small subset of inactive genes that must be negatively regulated during kernel development is also targeted by HDA101 and its loss leads to hyperacetylation and increased expression of these inactive genes. Finally, we report that HDA101 interacts with members of different chromatin remodeling complexes, such as NFC103/MSI1 and SNL1/SIN3-like protein corepressors. Taken together, our results reveal a complex genetic network regulated by HDA101 during seed development and provide insight into the different mechanisms of HDA101-mediated regulation of transcriptionally active and inactive genes.
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Affiliation(s)
- Hua Yang
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, PR China
| | - Xinye Liu
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, PR China
| | - Mingming Xin
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, PR China
| | - Jinkun Du
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, PR China
| | - Zhaorong Hu
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, PR China
| | - HuiRu Peng
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, PR China
| | - Vincenzo Rossi
- Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria, Unità di Ricerca per la Maiscoltura, I-24126 Bergamo, Italy
| | - Qixin Sun
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, PR China
| | - Zhongfu Ni
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, PR China
| | - Yingyin Yao
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, PR China
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19
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Chettoor AM, Yi G, Gomez E, Hueros G, Meeley RB, Becraft PW. A putative plant organelle RNA recognition protein gene is essential for maize kernel development. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:236-46. [PMID: 24985738 DOI: 10.1111/jipb.12234] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 06/29/2014] [Indexed: 05/29/2023]
Abstract
Basal endosperm transfer layer (BETL) cells are responsible for transferring apoplastic solutes from the maternal pedicel into the endosperm, supplying the grain with compounds required for embryo development and storage reserve accumulation. Here, we analyze the maize (Zea mays L.) empty pericarp6 (emp6) mutant, which causes early arrest in grain development. The Emp6+gene function is required independently in both the embryo and endosperm. The emp6 mutant causes a notable effect on the differentiation of BETL cells; the extensive cell wall ingrowths that distinguish BETL cells are diminished and BETL marker gene expression is compromised in mutant kernels. Transposon tagging identified the emp6 locus as encoding a putative plant organelle RNA recognition (PORR) protein, 1 of 15 PORR family members in maize. The emp6 transcript is widely detected in plant tissues with highest levels in embryos and developing kernels. EMP6-green fluorescent protein (GFP) fusion proteins transiently expressed in Nicotiana benthamiana leaves were targeted specifically to mitochondria. These results suggest that BETL cell differentiation might be particularly energy intensive, or alternatively, that mitochondria might confer a developmental function.
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Affiliation(s)
- Antony M Chettoor
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, 50011, USA
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20
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Radchuk V, Borisjuk L. Physical, metabolic and developmental functions of the seed coat. FRONTIERS IN PLANT SCIENCE 2014; 5:510. [PMID: 25346737 PMCID: PMC4193196 DOI: 10.3389/fpls.2014.00510] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 09/11/2014] [Indexed: 05/04/2023]
Abstract
The conventional understanding of the role of the seed coat is that it provides a protective layer for the developing zygote. Recent data show that the picture is more nuanced. The seed coat certainly represents a first line of defense against adverse external factors, but it also acts as channel for transmitting environmental cues to the interior of the seed. The latter function primes the seed to adjust its metabolism in response to changes in its external environment. The purpose of this review is to provide the reader with a comprehensive view of the structure and functionality of the seed coat, and to expose its hidden interaction with both the endosperm and embryo. Any breeding and/or biotechnology intervention seeking to increase seed size or modify seed features will have to consider the implications on this tripartite interaction.
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Affiliation(s)
| | - Ljudmilla Borisjuk
- Heterosis, Molecular Genetics, Leibniz-Institut für Pflanzengenetik und KulturpflanzenforschungGatersleben, Germany
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21
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Leroux BM, Goodyke AJ, Schumacher KI, Abbott CP, Clore AM, Yadegari R, Larkins BA, Dannenhoffer JM. Maize early endosperm growth and development: from fertilization through cell type differentiation. AMERICAN JOURNAL OF BOTANY 2014; 101:1259-74. [PMID: 25104551 DOI: 10.3732/ajb.1400083] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
UNLABELLED • PREMISE OF THE STUDY Given the worldwide economic importance of maize endosperm, it is surprising that its development is not the most comprehensively studied of the cereals. We present detailed morphometric and cytological descriptions of endosperm development in the maize inbred line B73, for which the genome has been sequenced, and compare its growth with four diverse Nested Association Mapping (NAM) founder lines.• METHODS The first 12 d of B73 endosperm development were described using semithin sections of plastic-embedded kernels and confocal microscopy. Longitudinal sections were used to compare endosperm length, thickness, and area.• KEY RESULTS Morphometric comparison between Arizona- and Michigan-grown B73 showed a common pattern. Early endosperm development was divided into four stages: coenocytic, cellularization through alveolation, cellularization through partitioning, and differentiation. We observed tightly synchronous nuclear divisions in the coenocyte, elucidated that the onset of cellularization was coincident with endosperm size, and identified a previously undefined cell type (basal intermediate zone, BIZ). NAM founders with small mature kernels had larger endosperms (0-6 d after pollination) than lines with large mature kernels.• CONCLUSIONS Our B73-specific model of early endosperm growth links developmental events to relative endosperm size, while accounting for diverse growing conditions. Maize endosperm cellularizes through alveolation, then random partitioning of the central vacuole. This unique cellularization feature of maize contrasts with the smaller endosperms of Arabidopsis, barley, and rice that strictly cellularize through repeated alveolation. NAM analysis revealed differences in endosperm size during early development, which potentially relates to differences in timing of cellularization across diverse lines of maize.
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Affiliation(s)
- Brian M Leroux
- Department of Biology, Central Michigan University, Mount Pleasant, Michigan 48859 USA
| | - Austin J Goodyke
- Department of Biology, Central Michigan University, Mount Pleasant, Michigan 48859 USA
| | - Katelyn I Schumacher
- Department of Biology, Central Michigan University, Mount Pleasant, Michigan 48859 USA
| | - Chelsi P Abbott
- Department of Biology, Central Michigan University, Mount Pleasant, Michigan 48859 USA
| | - Amy M Clore
- Division of Natural Sciences, New College of Florida, Sarasota, Florida 34243 USA
| | - Ramin Yadegari
- School of Plant Sciences, University of Arizona, Tucson, Arizona 85721 USA
| | - Brian A Larkins
- School of Plant Sciences, University of Arizona, Tucson, Arizona 85721 USA
| | - Joanne M Dannenhoffer
- Department of Biology, Central Michigan University, Mount Pleasant, Michigan 48859 USA
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22
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Zheng Y, Wang Z, Gu Y. Development and function of caryopsis transport tissues in maize, sorghum and wheat. PLANT CELL REPORTS 2014; 33:1023-31. [PMID: 24652624 DOI: 10.1007/s00299-014-1593-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 02/26/2014] [Indexed: 05/26/2023]
Abstract
Cereal caryopsis transport tissues are essential channels via which nutrients are transported into the embryo and endosperm. There are differences and similarities between caryopsis transport tissues of maize, sorghum and wheat. Vascular bundle, endosperm transfer cells, endosperm conducting cells and embryo surrounding region are common in maize, sorghum and wheat. Placentochalaza is special in maize and sorghum, while chalaza and nucellar projection transfer cells are special in wheat. There is an obvious apoplastic cavity between maternal and filial tissues in sorghum and wheat caryopses, but there is no obvious apoplastic cavity in maize caryopsis. Based on the latest research, the development and function of the three cereal caryopsis transport tissues are discussed and investigated in this paper.
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Affiliation(s)
- Yankun Zheng
- College of Agriculture, Yangzhou University, Yangzhou, 225009, Jiangsu, China,
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23
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She W, Grimanelli D, Baroux C. An efficient method for quantitative, single-cell analysis of chromatin modification and nuclear architecture in whole-mount ovules in Arabidopsis. J Vis Exp 2014:e51530. [PMID: 24998753 PMCID: PMC4195603 DOI: 10.3791/51530] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
In flowering plants, the somatic-to-reproductive cell fate transition is marked by the specification of spore mother cells (SMCs) in floral organs of the adult plant. The female SMC (megaspore mother cell, MMC) differentiates in the ovule primordium and undergoes meiosis. The selected haploid megaspore then undergoes mitosis to form the multicellular female gametophyte, which will give rise to the gametes, the egg cell and central cell, together with accessory cells. The limited accessibility of the MMC, meiocyte and female gametophyte inside the ovule is technically challenging for cytological and cytogenetic analyses at single cell level. Particularly, direct or indirect immunodetection of cellular or nuclear epitopes is impaired by poor penetration of the reagents inside the plant cell and single-cell imaging is demised by the lack of optical clarity in whole-mount tissues. Thus, we developed an efficient method to analyze the nuclear organization and chromatin modification at high resolution of single cell in whole-mount embedded Arabidopsis ovules. It is based on dissection and embedding of fixed ovules in a thin layer of acrylamide gel on a microscopic slide. The embedded ovules are subjected to chemical and enzymatic treatments aiming at improving tissue clarity and permeability to the immunostaining reagents. Those treatments preserve cellular and chromatin organization, DNA and protein epitopes. The samples can be used for different downstream cytological analyses, including chromatin immunostaining, fluorescence in situ hybridization (FISH), and DNA staining for heterochromatin analysis. Confocal laser scanning microscopy (CLSM) imaging, with high resolution, followed by 3D reconstruction allows for quantitative measurements at single-cell resolution.
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Affiliation(s)
- Wenjing She
- Institute of Plant Biology and Zürich-Basel Plant Science Center, University of Zürich
| | - Daniel Grimanelli
- Institut de Recherche pour le Développement (UMR 232), Centre National de la Recherche Scientifique (ERL 5300), Université de Montpellier II
| | - Célia Baroux
- Institute of Plant Biology and Zürich-Basel Plant Science Center, University of Zürich;
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24
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Muñiz LM, Gómez E, Guyon V, López M, Khbaya B, Sellam O, Peréz P, Hueros G. A PCR-based forward genetics screening, using expression domain-specific markers, identifies mutants in endosperm transfer cell development. FRONTIERS IN PLANT SCIENCE 2014; 5:158. [PMID: 24808899 PMCID: PMC4009440 DOI: 10.3389/fpls.2014.00158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 04/06/2014] [Indexed: 05/07/2023]
Abstract
Mutant collections are an invaluable source of material on which forward genetic approaches allow the identification of genes affecting a wide variety of biological processes. However, some particular developmental stages and morphological structures may resist analysis due to their physical inaccessibility or to deleterious effects associated to their modification. Furthermore, lethal mutations acting early in development may escape detection. We have approached the characterization of 101 maize seed mutants, selected from a collection of 27,500 visually screened Mu-insertion lines, using a molecular marker approach based on a set of genes previously ascribed to different tissue compartments within the early developing kernel. A streamlined combination of qRT-PCR assays has allowed us to preliminary pinpoint the affected compartment, establish developmental comparisons to WT siblings and select mutant lines with alterations in the different compartments. Furthermore, clusters of markers co-affected by the underlying mutation were identified. We have analyzed more extensively a set of lines presenting significant variation in transfer cell-associated expression markers, and have performed morphological observations, and immunolocalization experiments to confirm the results, validating this approach as an efficient mutant description tool.
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Affiliation(s)
- Luis M. Muñiz
- Departamento Biomedicina and Biotecnología (Genética), Universidad de AlcaláAlcalá de Henares, Spain
| | - Elisa Gómez
- Departamento Biomedicina and Biotecnología (Genética), Universidad de AlcaláAlcalá de Henares, Spain
| | - Virginie Guyon
- GM Trait Discovery, Biogemma, Centre de Recherche de ChappesChappes, France
| | - Maribel López
- Departamento Biomedicina and Biotecnología (Genética), Universidad de AlcaláAlcalá de Henares, Spain
| | - Bouchaib Khbaya
- GM Trait Discovery, Biogemma, Centre de Recherche de ChappesChappes, France
| | - Olivier Sellam
- GM Trait Discovery, Biogemma, Centre de Recherche de ChappesChappes, France
| | - Pascual Peréz
- GM Trait Discovery, Biogemma, Centre de Recherche de ChappesChappes, France
| | - Gregorio Hueros
- Departamento Biomedicina and Biotecnología (Genética), Universidad de AlcaláAlcalá de Henares, Spain
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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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Andriunas FA, Zhang HM, Xia X, Patrick JW, Offler CE. Intersection of transfer cells with phloem biology-broad evolutionary trends, function, and induction. FRONTIERS IN PLANT SCIENCE 2013; 4:221. [PMID: 23847631 PMCID: PMC3696738 DOI: 10.3389/fpls.2013.00221] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 06/07/2013] [Indexed: 05/18/2023]
Abstract
Transfer cells (TCs) are ubiquitous throughout the plant kingdom. Their unique ingrowth wall labyrinths, supporting a plasma membrane enriched in transporter proteins, provides these cells with an enhanced membrane transport capacity for resources. In certain plant species, TCs have been shown to function to facilitate phloem loading and/or unloading at cellular sites of intense resource exchange between symplasmic/apoplasmic compartments. Within the phloem, the key cellular locations of TCs are leaf minor veins of collection phloem and stem nodes of transport phloem. In these locations, companion and phloem parenchyma cells trans-differentiate to a TC morphology consistent with facilitating loading and re-distribution of resources, respectively. At a species level, occurrence of TCs is significantly higher in transport than in collection phloem. TCs are absent from release phloem, but occur within post-sieve element unloading pathways and particularly at interfaces between generations of developing Angiosperm seeds. Experimental accessibility of seed TCs has provided opportunities to investigate their inductive signaling, regulation of ingrowth wall formation and membrane transport function. This review uses this information base to explore current knowledge of phloem transport function and inductive signaling for phloem-associated TCs. The functional role of collection phloem and seed TCs is supported by definitive evidence, but no such information is available for stem node TCs that present an almost intractable experimental challenge. There is an emerging understanding of inductive signals and signaling pathways responsible for initiating trans-differentiation to a TC morphology in developing seeds. However, scant information is available to comment on a potential role for inductive signals (auxin, ethylene and reactive oxygen species) that induce seed TCs, in regulating induction of phloem-associated TCs. Biotic phloem invaders have been used as a model to speculate on involvement of these signals.
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Affiliation(s)
| | | | | | | | - Christina E. Offler
- Department of Biological Sciences, School of Environmental and Life Sciences, The University of NewcastleCallaghan, NSW, Australia
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Spielbauer G, Li L, Römisch-Margl L, Do PT, Fouquet R, Fernie AR, Eisenreich W, Gierl A, Settles AM. Chloroplast-localized 6-phosphogluconate dehydrogenase is critical for maize endosperm starch accumulation. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:2231-42. [PMID: 23530131 PMCID: PMC3654415 DOI: 10.1093/jxb/ert082] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plants have duplicate versions of the oxidative pentose phosphate pathway (oxPPP) enzymes with a subset localized to the chloroplast. The chloroplast oxPPP provides NADPH and pentose sugars for multiple metabolic pathways. This study identified two loss-of-function alleles of the Zea mays (maize) chloroplast-localized oxPPP enzyme 6-phosphogluconate dehydrogenase (6PGDH). These mutations caused a rough endosperm seed phenotype with reduced embryo oil and endosperm starch. Genetic translocation experiments showed that pgd3 has separate, essential roles in both endosperm and embryo development. Endosperm metabolite profiling experiments indicated that pgd3 shifts redox-related metabolites and increases reducing sugars similar to starch-biosynthetis mutants. Heavy isotope-labelling experiments indicates that carbon flux into starch is altered in pgd3 mutants. Labelling experiments with a loss of cytosolic 6PGDH did not affect flux into starch. These results support the known role for plastid-localized oxPPP in oil synthesis and argue that amyloplast-localized oxPPP reactions are integral to endosperm starch accumulation in maize kernels.
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Affiliation(s)
- Gertraud Spielbauer
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA
| | - Li Li
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA
| | - Lilla Römisch-Margl
- Lehrstuhl für Genetik, Technische Universität München, 85354 Freising, Germany
| | - Phuc Thi Do
- Max-Planck-Institut für Molekulare Pflanzenphysiologie; Potsdam-Golm, Germany
| | - Romain Fouquet
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA
| | - Alisdair R. Fernie
- Max-Planck-Institut für Molekulare Pflanzenphysiologie; Potsdam-Golm, Germany
| | - Wolfgang Eisenreich
- Lehrstuhl für Biochemie, Technische Universität München, 85747 Garching, Germany
| | - Alfons Gierl
- Lehrstuhl für Genetik, Technische Universität München, 85354 Freising, Germany
| | - A. Mark Settles
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA
- * To whom correspondence should be addressed. E-mail:
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Ngo QA, Baroux C, Guthörl D, Mozerov P, Collinge MA, Sundaresan V, Grossniklaus U. The Armadillo repeat gene ZAK IXIK promotes Arabidopsis early embryo and endosperm development through a distinctive gametophytic maternal effect. THE PLANT CELL 2012; 24:4026-43. [PMID: 23064319 PMCID: PMC3517234 DOI: 10.1105/tpc.112.102384] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The proper balance of parental genomic contributions to the fertilized embryo and endosperm is essential for their normal growth and development. The characterization of many gametophytic maternal effect (GME) mutants affecting seed development indicates that there are certain classes of genes with a predominant maternal contribution. We present a detailed analysis of the GME mutant zak ixik (zix), which displays delayed and arrested growth at the earliest stages of embryo and endosperm development. ZIX encodes an Armadillo repeat (Arm) protein highly conserved across eukaryotes. Expression studies revealed that ZIX manifests a GME through preferential maternal expression in the early embryo and endosperm. This parent-of-origin-dependent expression is regulated by neither the histone and DNA methylation nor the DNA demethylation pathways known to regulate some other GME mutants. The ZIX protein is localized in the cytoplasm and nucleus of cells in reproductive tissues and actively dividing root zones. The maternal ZIX allele is required for the maternal expression of miniseed3. Collectively, our results reveal a reproductive function of plant Arm proteins in promoting early seed growth, which is achieved through a distinct GME of ZIX that involves mechanisms for maternal allele-specific expression that are independent of the well-established pathways.
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Affiliation(s)
- Quy A. Ngo
- Institute of Plant Biology and Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zurich, Switzerland
- Section of Plant Biology, University of California, Davis, California 95616
- Address correspondence to
| | - Celia Baroux
- Institute of Plant Biology and Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zurich, Switzerland
| | - Daniela Guthörl
- Institute of Plant Biology and Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zurich, Switzerland
| | - Peter Mozerov
- Institute of Plant Biology and Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zurich, Switzerland
| | - Margaret A. Collinge
- Institute of Plant Biology and Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zurich, Switzerland
| | - Venkatesan Sundaresan
- Section of Plant Biology, University of California, Davis, California 95616
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Ueli Grossniklaus
- Institute of Plant Biology and Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zurich, Switzerland
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Becraft PW, Gutierrez-Marcos J. Endosperm development: dynamic processes and cellular innovations underlying sibling altruism. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2012; 1:579-93. [PMID: 23801534 DOI: 10.1002/wdev.31] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The endosperm is a product of fertilization that evolved to support and nourish its genetic twin sibling embryo. Cereal endosperm accumulates starch and protein stores, which later support the germinating seedling. These nutritional stores prompted the domestication of cereals and are the focus of ongoing efforts for crop improvement and biotechnological innovations. Endosperm development entails several novel modifications to basic cellular and developmental processes. Cereals display nuclear endosperm development, which begins with a period of free nuclear division to generate a coenocyte. Cytoskeletal arrays distribute nuclei around the periphery of the cytoplasm and direct the subsequent deposition of cell wall material during cellularization. Positional cues and signaling systems function dynamically in the specification of the four major cell types: transfer cells, embryo-surrounding cells, starchy endosperm (SE), and aleurone. Genome balance, epigenetic gene regulation, and parent-of-origin effects are essential for directing these processes. Transfer cells transport solutes, including sugars and amino acids, from the maternal plant tissues into the developing grain where they are partitioned between embryo and SE cells. Cells of the embryo-surrounding region appear to coordinate development of the embryo and endosperm. As the seed matures, SE cells assimilate starch and protein stores, undergo DNA endoreduplication, and finally undergo programmed cell death. In contrast, aleurone cells follow a maturation program similar to the embryo, allowing them to survive desiccation. At germination, the aleurone cells secrete amylases and proteases that hydrolyze the storage products of the SE to nourish the germinating seedling.
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Affiliation(s)
- Philip W Becraft
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA.
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Maternal control of nutrient allocation in plant seeds by genomic imprinting. Curr Biol 2012; 22:160-5. [PMID: 22245001 DOI: 10.1016/j.cub.2011.11.059] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 10/25/2011] [Accepted: 11/28/2011] [Indexed: 11/20/2022]
Abstract
Imprinted genes are commonly expressed in mammalian placentas and in plant seed endosperms, where they exhibit preferential uniparental allelic expression. In mammals, imprinted genes directly regulate placental function and nutrient distribution from mother to fetus; however, none of the >60 imprinted genes thus far reported in plants have been demonstrated to play an equivalent role in regulating the flow of resources to the embryo. Here we show that imprinted Maternally expressed gene1 (Meg1) in maize is both necessary and sufficient for the establishment and differentiation of the endosperm nutrient transfer cells located at the mother:seed interface. Consistent with these findings, Meg1 also regulates maternal nutrient uptake, sucrose partitioning, and seed biomass yield. In addition, we generated an imprinted and nonimprinted synthetic Meg1 ((syn)Meg1) dosage series whereby increased dosage and absence of imprinting both resulted in an unequal investment of maternal resources into the endosperm. These findings highlight dosage regulation by genomic imprinting as being critical for maintaining a balanced distribution of maternal nutrients to filial tissues in plants, as in mammals. However, unlike in mammals, Meg1 is a maternally expressed imprinted gene that surprisingly acts to promote rather than restrict nutrient allocation to the offspring.
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31
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Fouquet R, Martin F, Fajardo DS, Gault CM, Gómez E, Tseung CW, Policht T, Hueros G, Settles AM. Maize rough endosperm3 encodes an RNA splicing factor required for endosperm cell differentiation and has a nonautonomous effect on embryo development. THE PLANT CELL 2011; 23:4280-97. [PMID: 22138152 PMCID: PMC3269866 DOI: 10.1105/tpc.111.092163] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 09/30/2011] [Accepted: 11/18/2011] [Indexed: 05/18/2023]
Abstract
Endosperm and embryo development are coordinated via epigenetic regulation and signaling between these tissues. In maize (Zea mays), the endosperm-embryo signals are not known, but endosperm cellularization is a key event for embryos to form shoots and roots. We screened seed mutants for nonautonomous functions in endosperm and embryo development with genetically nonconcordant seeds and identified the recessive mutant rough endosperm3 (rgh3). The wild-type Rgh3 allele is required in the endosperm for embryos to develop and has an autonomous role in embryo and seedling development. Endosperm cell differentiation is defective in rgh3. Results from endosperm cell culture indicate that rgh3 mutants remain in a proliferative state through mid-seed development. Rgh3 encodes the maize U2AF(35) Related Protein (URP), an RNA splicing factor involved in both U2 and U12 splicing. The Rgh3 allele produces at least 19 alternative splice variants with only one isoform encoding a full-length ortholog to URP. The full-length RGH3α isoform localizes to the nucleolus and displays a speckled pattern within the nucleoplasm, and RGH3α colocalizes with U2AF(65). A survey of alternatively spliced transcripts found that, in the rgh3 mutant, a fraction of noncanonical splicing events are altered. Our findings suggest that differentiation of maize endosperm cell types is necessary for embryos to develop. The molecular cloning of Rgh3 suggests that alternative RNA splicing is needed for cell differentiation, development, and plant viability.
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Affiliation(s)
- Romain Fouquet
- Plant Molecular and Cellular Biology Program, Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611
| | - Federico Martin
- Plant Molecular and Cellular Biology Program, Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611
| | - Diego S. Fajardo
- Plant Molecular and Cellular Biology Program, Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611
| | - Christine M. Gault
- Plant Molecular and Cellular Biology Program, Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611
| | - Elisa Gómez
- Departamento de Biología Celular y Genética, Universidad de Alcalá, 28871 Alcalá de Henares (Madrid), Spain
| | - Chi-Wah Tseung
- Plant Molecular and Cellular Biology Program, Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611
| | - Tyler Policht
- Plant Molecular and Cellular Biology Program, Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611
| | - Gregorio Hueros
- Departamento de Biología Celular y Genética, Universidad de Alcalá, 28871 Alcalá de Henares (Madrid), Spain
| | - A. Mark Settles
- Plant Molecular and Cellular Biology Program, Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611
- Address correspondence to
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32
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Nuclear behavior, cell polarity, and cell specification in the female gametophyte. ACTA ACUST UNITED AC 2011; 24:123-36. [PMID: 21336612 DOI: 10.1007/s00497-011-0161-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2010] [Accepted: 01/15/2011] [Indexed: 12/18/2022]
Abstract
In flowering plants, the haploid gamete-forming generation comprises only a few cells and develops within the reproductive organs of the flower. The female gametophyte has become an attractive model system to study the genetic and molecular mechanisms involved in pattern formation and gamete specification. It originates from a single haploid spore through three free nuclear division cycles, giving rise to four different cell types. Research over recent years has allowed to catch a glimpse of the mechanisms that establish the distinct cell identities and suggests dynamic cell-cell communication to orchestrate not only development among the cells of the female gametophyte but also the interaction between male and female gametophytes. Additionally, cytological observations and mutant studies have highlighted the importance of nuclei migration- and positioning for patterning the female gametophyte. Here we review current knowledge on the mechanisms of cell specification in the female gametophyte, emphasizing the importance of positional cues for the establishment of distinct molecular profiles.
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Analysis of stunter1, a maize mutant with reduced gametophyte size and maternal effects on seed development. Genetics 2011; 187:1085-97. [PMID: 21270392 DOI: 10.1534/genetics.110.125286] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Many higher eukaryotes have evolved strategies for the maternal control of growth and development of their offspring. In higher plants this is achieved in part by postmeiotic gene activity controlling the development of the haploid female gametophyte. stunter1 (stt1) is a novel, recessive, maternal effect mutant in maize that displays viable, miniature kernels. Maternal inheritance of stt1 results in seeds with reduced but otherwise normal endosperms and embryos. The stt1 mutation displays reduced transmission through the male and female parents and causes significant changes in the sizes of both male and female gametophytes. stt1 pollen grains are smaller than wild type, have reduced germination efficiency, and reduced pollen tube growth. stt1 embryo sacs have smaller central cells and abnormal antipodal cells that are larger, more vacuolated, and fewer in number than wild type. Embryos and endosperms produced by fertilization of stt1 embryo sacs develop and grow more slowly than wild type. The data suggest that the morphology of mutant embryo sacs influences endosperm development, leading to the production of miniature kernels in stt1. Analysis of seeds carrying a mutant maternal allele of stt1 over a deletion of the paternal allele demonstrates that both parental alleles are active after fertilization in both the endosperm and embryo. This analysis also indicates that embryo development until the globular stage in maize can proceed without endosperm development and is likely supported directly by the diploid mother plant.
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34
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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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35
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Zheng Y, Wang Z. Current opinions on endosperm transfer cells in maize. PLANT CELL REPORTS 2010; 29:935-942. [PMID: 20585949 DOI: 10.1007/s00299-010-0891-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 06/16/2010] [Accepted: 06/17/2010] [Indexed: 05/29/2023]
Abstract
Endosperm transfer cells (ETC) mainly occur in the endosperm epithelial layer near the pedicel. They transport the nutrient unloaded by the maternal vascular tissue to filial tissues. Wall ingrowths of ETC can facilitate solute transportation. Sugar, especially glucose, is found to modulate the promoter activity of ZmMRP-1, a determinant of transfer cell-specific expression. The ZmMRP-1-encoded protein can transactivate the promoters of transfer cell-specific genes. Signalling and early events leading to wall ingrowth formation depend upon gene expression. Sucrose synthase and the cytoskeleton probably play a primary role in the wall ingrowth formation. The major solutes transferred by ETC are amino acids, sucrose, and monosaccharides, which is consistent with the expression of their transporters and transport-associated genes. In this paper, we review current opinions on the differentiation, wall ingrowth formation, and function of ETC in maize. According to the experimental materials provided by predecessors, we also give some speculations about the differentiation mechanisms of ETC and process of wall ingrowth formation.
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Affiliation(s)
- Yankun Zheng
- The Key Laboratory of Crop Physiology and Genetics of Yangzhou University, Yangzhou, Jiangsu, China.
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36
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Nadaud I, Girousse C, Debiton C, Chambon C, Bouzidi MF, Martre P, Branlard G. Proteomic and morphological analysis of early stages of wheat grain development. Proteomics 2010; 10:2901-10. [DOI: 10.1002/pmic.200900792] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kang BH, Xiong Y, Williams DS, Pozueta-Romero D, Chourey PS. Miniature1-encoded cell wall invertase is essential for assembly and function of wall-in-growth in the maize endosperm transfer cell. PLANT PHYSIOLOGY 2009; 151:1366-76. [PMID: 19759348 PMCID: PMC2773079 DOI: 10.1104/pp.109.142331] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Accepted: 09/14/2009] [Indexed: 05/18/2023]
Abstract
The miniature1 (mn1) seed phenotype in maize (Zea mays) is due to a loss-of-function mutation at the Mn1 locus that encodes a cell wall invertase (INCW2) that localizes exclusively to the basal endosperm transfer cells (BETCs) of developing seeds. A common feature of all transfer cells is the labyrinth-like wall-in-growth (WIG) that increases the plasma membrane area, thereby enhancing transport capacity in these cells. To better understand WIG formation and roles of INCW2 in the BETC development, we examined wild-type and mn1 mutant developing kernels by cryofixation and electron microscopy. In Mn1 seeds, WIGs developed uniformly in the BETC layer during 7 to 17 d after pollination, and the secretory/endocytic organelles proliferated in the BETCs. Mitochondria accumulated in the vicinity of WIGs, suggesting a functional link between them. In the mn1 BETCs, WIGs were stunted and their endoplasmic reticulum was swollen; Golgi density in the mutant BETCs was 51% of the Mn1 Golgi density. However, the polarized distribution of mitochondria was not affected. INCW2-specific immunogold particles were detected in WIGs, the endoplasmic reticulum, Golgi stacks, and the trans-Golgi network in the Mn1 BETCs, while immunogold particles were extremely rare in the mutant BETCs. Levels of WIG development in the empty pericarp4 mutant was heterogeneous among BETCs, and INCW2 immunogold particles were approximately four times more abundant in the larger WIGs than in the stunted WIGs. These results indicate that polarized secretion is activated during WIG formation and that INCW2 is required for normal development of WIGs to which INCW2 is localized.
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Affiliation(s)
- Byung-Ho Kang
- Department of Microbiology, University of Florida, Gainesville, Florida 32611, USA.
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Dermastia M, Kladnik A, Dolenc Koce J, Chourey PS. A cellular study of teosinte Zea mays subsp. parviglumis (Poaceae) caryopsis development showing several processes conserved in maize. AMERICAN JOURNAL OF BOTANY 2009; 96:1798-807. [PMID: 21622300 DOI: 10.3732/ajb.0900059] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The evolutionary history of maize (Zea mays subsp. mays) is of general interest because of its economic and scientific importance. Here we show that many cellular traits described previously in developing caryopses of maize are also seen in its wild progenitor teosinte (Zea mays subsp. parviglumis). These features, each with a possible role in development, include (1) an early programmed cell death in the maternal placento-chalazal (P-C) layer that may lead to increased hydrolytic conductance to the developing seed; (2) accumulation of phenolics and flavonoids in the P-C layer that may be related to antimicrobial activity; (3) formation of wall ingrowths in the basal endosperm transfer layer (BETL); (4) localization of cell wall invertase in the BETL, which is attributed to the increased transport capacity of photosynthates to the sink; and (5) endoreduplication in endosperm nuclei suggested to contribute to increased gene expression and greater sink capacity of the developing seed. In maize caryopsis, these cellular traits have been previously attributed to domestication and selection for larger seed size and vigor. Given the conservation of the entire cellular program in developing teosinte caryopses described here, we suggest that these traits evolved independently of domestication and predate human selection pressure.
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Affiliation(s)
- Marina Dermastia
- National Institute of Biology, Vecna pot 111, 1000 Ljubljana, Slovenia
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39
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Calixto CPG, Goldman GH, Goldman MHS. Analyses of sexual reproductive success in transgenic and/or mutant plants. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2009; 51:719-26. [PMID: 19686369 DOI: 10.1111/j.1744-7909.2009.00845.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The pistil, the female reproductive organ of plants, is a key player in the success of sexual plant reproduction. Ultimately, the production of fruits and seeds depends on the proper pistil development and function. Therefore, the identification and characterization of pistil expressed genes is essential for a better understanding and manipulation of the plant reproduction process. For studying the function of pistil expressed genes, transgenic and/or mutant plants for the genes of interest are used. The present article provides a review of methods already exploited to analyze sexual reproductive success. We intend to supply useful information and to guide future experiments in the study of genes affecting pistil development and function.
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Affiliation(s)
- Cristiane P G Calixto
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Brazil
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40
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Sabelli PA, Larkins BA. The development of endosperm in grasses. PLANT PHYSIOLOGY 2009; 149:14-26. [PMID: 19126691 PMCID: PMC2613697 DOI: 10.1104/pp.108.129437] [Citation(s) in RCA: 264] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Accepted: 10/18/2008] [Indexed: 05/18/2023]
Affiliation(s)
- Paolo A Sabelli
- Department of Plant Sciences, University of Arizona, Tucson, Arizona 85721, USA
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41
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Pennington PD, Costa LM, Gutierrez-Marcos JF, Greenland AJ, Dickinson HG. When genomes collide: aberrant seed development following maize interploidy crosses. ANNALS OF BOTANY 2008; 101:833-43. [PMID: 18276791 PMCID: PMC2710208 DOI: 10.1093/aob/mcn017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
BACKGROUND AND AIMS The results of wide- or interploidy crosses in angiosperms are unpredictable and often lead to seed abortion. The consequences of reciprocal interploidy crosses have been explored in maize in detail, focusing on alterations to tissue domains in the maize endosperm, and changes in endosperm-specific gene expression. METHODS Following reciprocal interploidy crosses between diploid and tetraploid maize lines, development of endosperm domains was studied using GUS reporter lines, and gene expression in resulting kernels was investigated using semi-quantitative RT-PCR on endosperms isolated at different stages of development. KEY RESULTS Reciprocal interploidy crosses result in very small, largely infertile seeds with defective endosperms. Seeds with maternal genomic excess are smaller than those with paternal genomic excess, their endosperms cellularize earlier and they accumulate significant quantities of starch. Endosperms from the reciprocal cross undergo an extended period of cell proliferation, and accumulate little starch. Analysis of reporter lines and gene expression studies confirm that functional domains of the endosperm are severely disrupted, and are modified differently according to the direction of the interploidy cross. CONCLUSIONS Interploidy crosses affect factors which regulate the balance between cell proliferation and cell differentiation within the endosperm. In particular, unbalanced crosses in maize affect transfer cell differentiation, and lead to the temporal deregulation of the ontogenic programme of endosperm development.
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42
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Genome-wide analysis of gene expression profiles during the kernel development of maize (Zea mays L.). Genomics 2008; 91:378-87. [PMID: 18280698 DOI: 10.1016/j.ygeno.2007.12.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Revised: 10/26/2007] [Accepted: 12/05/2007] [Indexed: 11/23/2022]
Abstract
Maize kernel is an important source of food, feed, and industrial raw materials. The elucidation of the molecular mechanisms of maize kernel development will be helpful for the manipulation of maize improvements. A microarray with approximately 58,000 probes was used to study dynamic gene expression during kernel development from fertilization to physiological maturity. By comparing six consecutive time points, 3445 differentially expressed genes were identified. These genes were then grouped into 10 clusters showing specific expression patterns using a K-means clustering algorithm. An investigation of function and expression patterns of genes elucidate the regulation mechanism underlying the important developmental processes cell division and kernel filling. The differential expression of genes involved in plant hormone signaling pathways suggested that phytohormone might play a critical role in the kernel developmental process. Moreover, regulation of some transcription factors and protein kinases might be involved in the whole developmental process.
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Berger F, Grini PE, Schnittger A. Endosperm: an integrator of seed growth and development. CURRENT OPINION IN PLANT BIOLOGY 2006; 9:664-70. [PMID: 17011228 DOI: 10.1016/j.pbi.2006.09.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2006] [Accepted: 09/20/2006] [Indexed: 05/08/2023]
Abstract
Plant reproduction relies on interactions between parental and zygotic components. Elaborate reciprocal signaling pathways enable coordination of the genetic programs between these components. A first and important step in this communication is the tight control of cell cycle events in the gametes prior to fertilization. This prepares for coordinated fertilization and the initiation of seed development. The dialog between the various actors of reproduction extends after fertilization, with the endosperm taking a central role. Importantly, the endosperm mediates a maternal input that is based on memory of the transcriptional states of imprinted genes, which is crucial for harmonious seed growth. Our current knowledge suggests that the endosperm is an integrator of the different components and genetic programs that are involved in seed development.
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Affiliation(s)
- Frédéric Berger
- Temasek Lifescience Laboratory, 1 Research Link, National University of Singapore, 117604, Singapore.
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