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Jonsson K, Hamant O, Bhalerao RP. Plant cell walls as mechanical signaling hubs for morphogenesis. Curr Biol 2022; 32:R334-R340. [PMID: 35413265 DOI: 10.1016/j.cub.2022.02.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The instructive role of mechanical cues during morphogenesis is increasingly being recognized in all kingdoms. Patterns of mechanical stress depend on shape, growth and external factors. In plants, the cell wall integrates these three parameters to function as a hub for mechanical feedback. Plant cells are interconnected by cell walls that provide structural integrity and yet are flexible enough to act as both targets and transducers of mechanical cues. Such cues may act locally at the subcellular level or across entire tissues, requiring tight control of both cell-wall composition and cell-cell adhesion. Here we focus on how changes in cell-wall chemistry and mechanics act in communicating diverse cues to direct growth asymmetries required for plant morphogenesis. We explore the role of cellulose microfibrils, microtubule arrays and pectin methylesterification in the transduction of mechanical cues during morphogenesis. Plant hormones can affect the mechanochemical composition of the cell wall and, in turn, the cell wall can modulate hormone signaling pathways, as well as the tissue-level distribution of these hormones. This also leads us to revisit the position of biochemical growth factors, such as plant hormones, acting both upstream and downstream of mechanical signaling. Finally, while the structure of the cell wall is being elucidated with increasing precision, existing data clearly show that the integration of genetic, biochemical and theoretical studies will be essential for a better understanding of the role of the cell wall as a hub for the mechanical control of plant morphogenesis.
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Affiliation(s)
- Kristoffer Jonsson
- IRBV, Department of Biological Sciences, University of Montreal, 4101 Sherbrooke East, Montreal, QC H1X 2B2, Canada.
| | - Olivier Hamant
- Laboratoire Reproduction et Developpement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, 69364 Lyon, France
| | - Rishikesh P Bhalerao
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 90187 Umeå, Sweden.
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2
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Sakai Y, Higaki T, Ishizaki K, Nishihama R, Kohchi T, Hasezawa S. Migration of prospindle before the first asymmetric division in germinating spore of Marchantia polymorpha. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2022; 39:5-12. [PMID: 35800969 PMCID: PMC9200083 DOI: 10.5511/plantbiotechnology.21.1217b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/17/2021] [Indexed: 05/11/2023]
Abstract
The development of the plant body starts with spore germination in bryophytes. In many cases, the first division of the spore occurs after germination and cell elongation of the spore. In Marchantia polymorpha, asymmetric division occurs upon spore germination to generate two daughter cells: the larger one retains the ability to divide and develops into the thallus via sporeling or protonema, while the smaller one maintains tip growth and differentiates into the first rhizoid, providing a scaffold for initial development. Although spore germination of M. polymorpha was described in the 19th century, the intracellular processes of the first asymmetric division of the spore have not been well characterized. In this study, we used live-cell imaging analyses to elucidate microtubule dynamics during the first asymmetric division concomitantly with germination. In particular, we demonstrated that the preprophase band was not formed in the spore and that the bipolar prospindle, which is a microtubule structure surrounding the nucleus during prophase, migrated from the center to the periphery in the spore, suggesting that it was the earliest visible sign of cell polarity. We also showed that the occurrence of asymmetric division depended on actin filaments. Our findings regarding the first division of the spore in M. polymorpha will lead to a better model for cell-autonomous asymmetric division in plants.
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Affiliation(s)
- Yuuki Sakai
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan
- Graduate School of Sciences, Kobe University, Nada-ku, Kobe 657-8501, Japan
- E-mail: Tel: +81-78-803-5727
| | - Takumi Higaki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan
- Faculty of Advanced Science and Technology, Kumamoto University, Chuo-ku, Kumamoto 860-8555 Japan
| | - Kimitsune Ishizaki
- Graduate School of Sciences, Kobe University, Nada-ku, Kobe 657-8501, Japan
| | - Ryuichi Nishihama
- Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
- Faculty of Science and Technology, Department of Applied Biological Science, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - Takayuki Kohchi
- Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Seiichiro Hasezawa
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan
- Graduate School of Science and Engineering, Hosei University, Koganei, Tokyo 184-8584 Japan
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3
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Do Plasmodesmata Play a Prominent Role in Regulation of Auxin-Dependent Genes at Early Stages of Embryogenesis? Cells 2021; 10:cells10040733. [PMID: 33810252 PMCID: PMC8066550 DOI: 10.3390/cells10040733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/21/2021] [Accepted: 03/24/2021] [Indexed: 01/24/2023] Open
Abstract
Plasmodesmata form intercellular channels which ensure the transport of various molecules during embryogenesis and postembryonic growth. However, high permeability of plasmodesmata may interfere with the establishment of auxin maxima, which are required for cellular patterning and the development of distinct tissues. Therefore, diffusion through plasmodesmata is not always desirable and the symplastic continuum must be broken up to induce or accomplish some developmental processes. Many data show the role of auxin maxima in the regulation of auxin-responsive genes and the establishment of various cellular patterns. However, still little is known whether and how these maxima are formed in the embryo proper before 16-cell stage, that is, when there is still a nonpolar distribution of auxin efflux carriers. In this work, we focused on auxin-dependent regulation of plasmodesmata function, which may provide rapid and transient changes of their permeability, and thus take part in the regulation of gene expression.
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4
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Khanday I, Sundaresan V. Plant zygote development: recent insights and applications to clonal seeds. CURRENT OPINION IN PLANT BIOLOGY 2021; 59:101993. [PMID: 33422964 DOI: 10.1016/j.pbi.2020.101993] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/11/2020] [Accepted: 12/15/2020] [Indexed: 05/22/2023]
Abstract
In flowering plants, haploid gametes - an egg cell and a sperm cell fuse to form the first diploid cell - the zygote. The zygote is the progenitor stem cell that gives rise to all the embryonic and post embryonic tissues and organs. Unlike animals, both maternal and paternal gene products participate in the initial development of zygotes in plants. Here, we discuss recent advances in understanding of the zygotic transition and embryo initiation in angiosperms, including the role of parental contributions to gene expression in the zygote. We further discuss utilization of this knowledge in agricultural biotechnology through synthetic apomixis. Parthenogenesis obtained by manipulation of embryogenic factors, combined with mutations that bypass meiosis, enables clonal propagation of hybrid crops through seeds.
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Affiliation(s)
- Imtiyaz Khanday
- Department of Plant Biology, University of California, Davis, CA, USA; Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Venkatesan Sundaresan
- Department of Plant Biology, University of California, Davis, CA, USA; Innovative Genomics Institute, University of California, Berkeley, CA, USA; Department of Plant Sciences, University of California, Davis, CA, USA.
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5
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Winnicki K. The Winner Takes It All: Auxin-The Main Player during Plant Embryogenesis. Cells 2020; 9:E606. [PMID: 32138372 PMCID: PMC7140527 DOI: 10.3390/cells9030606] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 02/21/2020] [Accepted: 02/27/2020] [Indexed: 12/11/2022] Open
Abstract
In plants, the first asymmetrical division of a zygote leads to the formation of two cells with different developmental fates. The establishment of various patterns relies on spatial and temporal gene expression, however the precise mechanism responsible for embryonic patterning still needs elucidation. Auxin seems to be the main player which regulates embryo development and controls expression of various genes in a dose-dependent manner. Thus, local auxin maxima and minima which are provided by polar auxin transport underlie cell fate specification. Diverse auxin concentrations in various regions of an embryo would easily explain distinct cell identities, however the question about the mechanism of cellular patterning in cells exposed to similar auxin concentrations still remains open. Thus, specification of cell fate might result not only from the cell position within an embryo but also from events occurring before and during mitosis. This review presents the impact of auxin on the orientation of the cell division plane and discusses the mechanism of auxin-dependent cytoskeleton alignment. Furthermore, close attention is paid to auxin-induced calcium fluxes, which regulate the activity of MAPKs during postembryonic development and which possibly might also underlie cellular patterning during embryogenesis.
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Affiliation(s)
- Konrad Winnicki
- Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lódź, Poland
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6
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Li G, Zou W, Jian L, Qian J, Zhao J. AtNSE1 and AtNSE3 are required for embryo pattern formation and maintenance of cell viability during Arabidopsis embryogenesis. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:6229-6244. [PMID: 31408172 PMCID: PMC6859727 DOI: 10.1093/jxb/erz373] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 08/06/2019] [Indexed: 05/30/2023]
Abstract
Embryogenesis is an essential process during seed development in higher plants. It has previously been shown that mutation of the Arabidopsis non-SMC element genes AtNSE1 or AtNSE3 leads to early embryo abortion, and their proteins can interact with each other directly. However, the crucial regions of these proteins in this interaction and how the proteins are cytologically involved in Arabidopsis embryo development are unknown. In this study, we found that the C-terminal including the Ring-like motif of AtNSE1 can interact with the N-terminal of AtNSE3, and only the Ring-like motif is essential for binding with three α motifs of AtNSE2 (homologous to AtMMS21). Using genetic assays and by analysing molecular markers of cell fate decisions (STM, WOX5, and WOX8) in mutant nse1 and nse3 embryos, we found that AtNSE1 and AtNSE3 work non-redundantly in early embryo development, and that differentiation of the apical meristem and the hypophysis fails in the mutants, which have disrupted auxin transportation and responses. However, the upper cells of the suspensor in the mutants seem to have proper embryo cell identity. Cytological examination showed that cell death occurred from the early embryo stage, and that vacuolar programmed cell death and necrosis in the nse1 and nse3 mutant embryos led to ovule abortion. Thus, AtNSE1 and AtNSE3 are essential for maintaining cell viability and growth during early embryogenesis. Our results improve our understanding of the functions of SMC5/6 complex in early embryogenesis in Arabidopsis.
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Affiliation(s)
- Gang Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Wenxuan Zou
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Liufang Jian
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jie Qian
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jie Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
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7
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Elias RA, Lando AP, Viana WG, Ortiz J, da Costa CD, Schmidt ÉC, Souza LA, Guerra MP, Steiner N. Structural aspects of cypsela and seed development of Trichocline catharinensis (Cabrera): a Brazilian endemic species. PROTOPLASMA 2019; 256:1495-1506. [PMID: 31144034 DOI: 10.1007/s00709-019-01361-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 02/20/2019] [Indexed: 06/09/2023]
Abstract
This is the first study to describe in a timescale morphohistological and ultrastructural characteristics of fruit (cypsela) and seed development in Trichocline catharinensis, which was completed 21 days after anthesis (DAA). At anthesis, we identified an ovary with three differentiated regions, including the inner epidermis, inner part, and outer epidermis. The mature ovule showed an integument with the outer epidermis, integumentary parenchyma, and endothelium. Cells around the endothelium form the periendothelial zone with thick cell walls that showed Periodic acid-Schiff (PAS)-positive reaction. The periendothelial zone and endothelium showed degradation of the cells during embryogenesis. The main stages of embryo development from fecundation through mature seed were identified. The ripe cypsela showed the pericarp (exocarp), seed coat (exotesta), and remaining endosperm surrounding the embryo. Mature embryos were straight with shoot apical meristem (SAM), and root apical meristem (RAM) was separated by the hypocotyl. Light microscopy (LM) and transmission electron microscopy (TEM) analyses indicate cells with characteristics of meristem cells, as well as proteins and lipid bodies and mitochondria with few cristae in cotyledon cells. Our findings provide insight into taxonomic and physiological studies by detailing cypsela and seed ontogenesis from an endemic and vulnerable Asteraceae from southern Brazil. This study is also a starting point for establishing the biological criteria for seed harvesting and future studies of seed physiology and conservation of plant genetic resource.
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Affiliation(s)
- Rosa Angelica Elias
- Plant Physiology Laboratory, Department of Botany, Federal University of Santa Catarina, Florianópolis, SC, 88040-900, Brazil
| | - Ana Paula Lando
- Plant Physiology Laboratory, Department of Botany, Federal University of Santa Catarina, Florianópolis, SC, 88040-900, Brazil
| | - Willian G Viana
- Plant Physiology Laboratory, Department of Botany, Federal University of Santa Catarina, Florianópolis, SC, 88040-900, Brazil
| | - Jacqueline Ortiz
- Plant Physiology Laboratory, Department of Botany, Federal University of Santa Catarina, Florianópolis, SC, 88040-900, Brazil
| | - Cláudia Dias da Costa
- Plant Physiology Laboratory, Department of Botany, Federal University of Santa Catarina, Florianópolis, SC, 88040-900, Brazil
| | - Éder Carlos Schmidt
- Plant Cell Biology Laboratory, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, C.P. 476, Florianópolis, SC, 88049-900, Brazil
| | - Luiz Antônio Souza
- Department of Biology, State University of Maringá, Av. Colombo 5790, Zona 7, Maringá, Paraná, 87020-900, Brazil
| | - Miguel Pedro Guerra
- Plant Developmental Physiology and Genetics Laboratory, Department of Plant Science, Federal University of Santa Catarina, Florianópolis, SC, 88034-001, Brazil
| | - Neusa Steiner
- Plant Physiology Laboratory, Department of Botany, Federal University of Santa Catarina, Florianópolis, SC, 88040-900, Brazil.
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8
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Genes involved in the deformations of the shoot apical meristem in somatic embryos of Capsicum chinense Jacq. J Genet 2019. [DOI: 10.1007/s12041-019-1117-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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9
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Winnicki K, Żabka A, Polit JT, Maszewski J. Mitogen-activated protein kinases concentrate in the vicinity of chromosomes and may regulate directly cellular patterning in Vicia faba embryos. PLANTA 2018; 248:307-322. [PMID: 29721610 DOI: 10.1007/s00425-018-2905-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 04/26/2018] [Indexed: 06/08/2023]
Abstract
Mitogen-activated protein kinases seem to mark genes which are set up to be activated in daughter cells and thus they may play a direct role in cellular patterning during embryogenesis. Embryonic patterning starts very early and after the first division of zygote different genes are expressed in apical and basal cells. However, there is an ongoing debate about the way these different transcription patterns are established during embryogenesis. The presented data indicate that mitogen-activated protein kinases (MAPKs) concentrate in the vicinity of chromosomes and form visible foci there. Cells in the apical and basal regions differ in number of foci observed during the metaphase which suggests that cellular patterning may be determined by activation of diverse MAPK-dependent genes. Different number of foci in each group of separating chromatids and the specified direction of these mitoses in apical-basal axis indicate that the unilateral auxin accumulation in a single cell may regulate the number of foci in each group of chromatids. Thus, we put forward a hypothesis that MAPKs localized in the vicinity of chromosomes during mitosis mark those genes which are set up to be activated in daughter cells after division. It implies that the chromosomal localization of MAPKs may be one of the mechanisms involved in establishment of cellular patterns in some plant species.
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Affiliation(s)
- Konrad Winnicki
- Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Lodz, ul. Pomorska 141/143, 90-236, Lodz, Poland.
| | - Aneta Żabka
- Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Lodz, ul. Pomorska 141/143, 90-236, Lodz, Poland
| | - Justyna Teresa Polit
- Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Lodz, ul. Pomorska 141/143, 90-236, Lodz, Poland
| | - Janusz Maszewski
- Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Lodz, ul. Pomorska 141/143, 90-236, Lodz, Poland
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10
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Xie F, Yan H, Sun Y, Wang Y, Chen H, Mao W, Zhang L, Sun M, Peng X. RPL18aB helps maintain suspensor identity during early embryogenesis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2018; 60:266-269. [PMID: 29193792 DOI: 10.1111/jipb.12616] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 11/28/2017] [Indexed: 06/07/2023]
Abstract
During embryogenesis, plants are thought to use a mechanism that allows the suspensor to maintain its identity. Here, we reported that RPL18aB is involved in this mechanism in Arabidopsis thaliana. The suspensor cells proliferated in rpl18aB and formed a multicellular structure rather than undergo programmed cell death, as in wild type. Suspensors of rpl18aB expressed the embryo proper marker, DRN::GFP, but not the suspensor marker, WOX8::GFP. In addition, auxin accumulated throughout the suspensors of rpl18aB proembryos. Suspensor-specific expression of RPL18aB could rescue the cell proliferation defects in rpl18aB suspensors. These findings supported a role for RPL18aB in maintaining suspensor identity.
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Affiliation(s)
- Fei Xie
- State Key Laboratory for Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Hailong Yan
- State Key Laboratory for Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yang Sun
- State Key Laboratory for Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yameng Wang
- State Key Laboratory for Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Hong Chen
- State Key Laboratory for Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Wanying Mao
- State Key Laboratory for Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Liyao Zhang
- State Key Laboratory for Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Mengxiang Sun
- State Key Laboratory for Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiongbo Peng
- State Key Laboratory for Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
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11
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Peng X, Sun MX. The suspensor as a model system to study the mechanism of cell fate specification during early embryogenesis. PLANT REPRODUCTION 2018; 31:59-65. [PMID: 29473100 PMCID: PMC5845063 DOI: 10.1007/s00497-018-0326-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 02/14/2018] [Indexed: 05/24/2023]
Abstract
The advances in the suspensor. During early embryogenesis, the proembryo consists of two domains, the embryo proper and the suspensor. Unlike the embryo proper, which has been investigated extensively, research on the suspensor has been limited in past decades. Recent studies have revealed that the suspensor plays an important role in early embryogenesis and the process of suspensor formation and degeneration may provide a unique model for studies on cell division pattern, cell fate determination, and cell death. In this review, we briefly summarize the advances in research on the suspensor, which provide new insight in our understanding of the mechanism of early embryogenesis and show great potential for a unique model for future investigations.
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Affiliation(s)
- Xiongbo Peng
- State Key Laboratory of Hybrid Rice, College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Science, Wuhan University, Wuhan, 430072, China.
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12
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Larsson E, Vivian-Smith A, Offringa R, Sundberg E. Auxin Homeostasis in Arabidopsis Ovules Is Anther-Dependent at Maturation and Changes Dynamically upon Fertilization. FRONTIERS IN PLANT SCIENCE 2017; 8:1735. [PMID: 29067034 PMCID: PMC5641375 DOI: 10.3389/fpls.2017.01735] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 09/22/2017] [Indexed: 05/20/2023]
Abstract
The plant hormone auxin is a vital component for plant reproduction as it regulates the development of both male and female reproductive organs, including ovules and gynoecia. Furthermore, auxin plays important roles in the development and growth of seeds and fruits. Auxin responses can be detected in ovules shortly after fertilization, and it has been suggested that this accumulation is a prerequisite for the developmental reprogramming of the ovules to seeds, and of the gynoecium to a fruit. However, the roles of auxin at the final stages of ovule development, and the sources of auxin leading to the observed responses in ovules after fertilization have remained elusive. Here we have characterized the auxin readout in Arabidopsis ovules, at the pre-anthesis, anthesis and in the immediate post-fertilization stages, using the R2D2 auxin sensor. In addition we have mapped the expression of auxin biosynthesis and conjugation genes, as well as that of auxin transporting proteins, during the same developmental stages. These analyses reveal specific spatiotemporal patterns of the different auxin homeostasis regulators. Auxin biosynthesis genes and auxin transport proteins define a pre-patterning of vascular cell identity in the pre-anthesis funiculus. Furthermore, our data suggests that auxin efflux from the ovule is restricted in an anther-dependent manner, presumably to synchronize reproductive organ development and thereby optimizing the chances of successful fertilization. Finally, de novo auxin biosynthesis together with reduced auxin conjugation and transport result in an enhanced auxin readout throughout the sporophytic tissues of the ovules soon after fertilization. Together, our results suggest a sophisticated set of regulatory cascades that allow successful fertilization and the subsequent transition of the female reproductive structures into seeds and fruits.
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Affiliation(s)
- Emma Larsson
- Institute of Biology Leiden, Plant Developmental Genetics, Leiden University, Leiden, Netherlands
- Department of Plant Biology, BioCentre and Linnean Centre for Plant Biology in Uppsala, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
- *Correspondence: Emma Larsson, Eva Sundberg,
| | - Adam Vivian-Smith
- Forest Genetics and Biodiversity, Norwegian Institute of Bioeconomy Research, Ås, Norway
| | - Remko Offringa
- Institute of Biology Leiden, Plant Developmental Genetics, Leiden University, Leiden, Netherlands
| | - Eva Sundberg
- Department of Plant Biology, BioCentre and Linnean Centre for Plant Biology in Uppsala, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
- *Correspondence: Emma Larsson, Eva Sundberg,
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13
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Pillitteri LJ, Guo X, Dong J. Asymmetric cell division in plants: mechanisms of symmetry breaking and cell fate determination. Cell Mol Life Sci 2016; 73:4213-4229. [PMID: 27286799 PMCID: PMC5522748 DOI: 10.1007/s00018-016-2290-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 06/02/2016] [Accepted: 06/02/2016] [Indexed: 02/07/2023]
Abstract
Asymmetric cell division is a fundamental mechanism that generates cell diversity while maintaining self-renewing stem cell populations in multicellular organisms. Both intrinsic and extrinsic mechanisms underpin symmetry breaking and differential daughter cell fate determination in animals and plants. The emerging picture suggests that plants deal with the problem of symmetry breaking using unique cell polarity proteins, mobile transcription factors, and cell wall components to influence asymmetric divisions and cell fate. There is a clear role for altered auxin distribution and signaling in distinguishing two daughter cells and an emerging role for epigenetic modifications through chromatin remodelers and DNA methylation in plant cell differentiation. The importance of asymmetric cell division in determining final plant form provides the impetus for its study in the areas of both basic and applied science.
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Affiliation(s)
- Lynn Jo Pillitteri
- Department of Biology, Western Washington University, Bellingham, WA, 98225, USA
| | - Xiaoyu Guo
- Waksman Institute of Microbiology, Rutgers the State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Juan Dong
- Waksman Institute of Microbiology, Rutgers the State University of New Jersey, Piscataway, NJ, 08854, USA.
- Department of Plant Biology and Pathology, Rutgers the State University of New Jersey, New Brunswick, NJ, 08901, USA.
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14
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15
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Qin Y, Dong J. Focusing on the focus: what else beyond the master switches for polar cell growth? MOLECULAR PLANT 2015; 8:582-94. [PMID: 25744359 PMCID: PMC5124495 DOI: 10.1016/j.molp.2014.12.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 12/24/2014] [Accepted: 12/29/2014] [Indexed: 05/21/2023]
Abstract
Cell polarity, often associated with polarized cell expansion/growth in plants, describes the uneven distribution of cellular components, such as proteins, nucleic acids, signaling molecules, vesicles, cytoskeletal elements, and organelles, which may ultimately modulate cell shape, structure, and function. Pollen tubes and root hairs are model cell systems for studying the molecular mechanisms underlying sustained tip growth. The formation of intercalated epidermal pavement cells requires excitatory and inhibitory pathways to coordinate cell expansion within single cells and between cells in contact. Strictly controlled cell expansion is linked to asymmetric cell division in zygotes and stomatal lineages, which require integrated processes of pre-mitotic cellular polarization and division asymmetry. While small GTPase ROPs are recognized as fundamental signaling switches for cell polarity in various cellular and developmental processes in plants, the broader molecular machinery underpinning polarity establishment required for asymmetric division remains largely unknown. Here, we review the widely used ROP signaling pathways in cell polar growth and the recently discovered feedback loops with auxin signaling and PIN effluxers. We discuss the conserved phosphorylation and phospholipid signaling mechanisms for regulating uneven distribution of proteins, as well as the potential roles of novel proteins and MAPKs in the polarity establishment related to asymmetric cell division in plants.
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Affiliation(s)
- Yuan Qin
- Center for Genomics and Biotechnology, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian Province, China
| | - Juan Dong
- Waksman Institute of Microbiology, Rutgers the State University of New Jersey, Piscataway, NJ 08854, USA; The Department of Plant Biology and Pathology, Rutgers the State University of New Jersey, New Brunswick, NJ 08901, USA.
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16
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Radoeva T, Weijers D. A roadmap to embryo identity in plants. TRENDS IN PLANT SCIENCE 2014; 19:709-16. [PMID: 25017700 DOI: 10.1016/j.tplants.2014.06.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 06/17/2014] [Accepted: 06/20/2014] [Indexed: 05/19/2023]
Abstract
Although plant embryogenesis is usually studied in the context of seed development, there are many alternative roads to embryo initiation. These include somatic embryogenesis in tissue culture and microspore embryogenesis, both widely used in breeding and crop propagation, but also include other modes of ectopic embryo initiation. In the past decades several genes, mostly transcription factors, were identified that can induce embryogenesis in somatic cells. Because the genetic networks in which such regulators operate to promote embryogenesis are largely unknown, a key question is how their activity relates to zygotic and alternative embryo initiation. We describe here the many roads to plant embryo initiation and discuss a framework for defining the developmental roles and mechanisms of plant embryogenesis regulators.
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Affiliation(s)
- Tatyana Radoeva
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
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17
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Ohnishi Y, Hoshino R, Okamoto T. Dynamics of Male and Female Chromatin during Karyogamy in Rice Zygotes. PLANT PHYSIOLOGY 2014; 165:1533-1543. [PMID: 24948834 PMCID: PMC4119036 DOI: 10.1104/pp.114.236059] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 06/14/2014] [Indexed: 05/20/2023]
Abstract
In angiosperms, the conversion of an egg cell into a zygote involves two sequential gametic processes: plasmogamy, the fusion of the plasma membranes of male and female gametes, and karyogamy, the fusion of the gametic nuclei. In this study, the nuclei and nuclear membranes of rice (Oryza sativa) gametes were fluorescently labeled using histones 2B-green fluorescent protein/red fluorescent protein and Sad1/UNC-84-domain protein2-green fluorescent protein, respectively, which were heterologously expressed. These gametes were fused in vitro to produce zygotes, and the nuclei and nuclear membranes in the zygotes were observed during karyogamy. The results indicated that the sperm nucleus migrates adjacent to the egg nucleus 5 to 10 min after plasmogamy via an actin cytoskelton, and the egg chromatin then appears to move unidirectionally into the sperm nucleus through a possible nuclear connection. The enlargement of the sperm nucleus accompanies this possible chromatin remodeling. Then, 30 to 70 min after fusion, the sperm chromatin begins to decondense with the completion of karyogamy. Based on these observations, the development of early rice zygotes from plasmogamy to karyogamy was divided into eight stages, and using reverse transcription PCR analyses, paternal and de novo synthesized transcripts were separately detected in zygotes at early and late karyogamy stages, respectively.
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Affiliation(s)
- Yukinosuke Ohnishi
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Rina Hoshino
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Takashi Okamoto
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan
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18
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Kajala K, Ramakrishna P, Fisher A, C. Bergmann D, De Smet I, Sozzani R, Weijers D, Brady SM. Omics and modelling approaches for understanding regulation of asymmetric cell divisions in arabidopsis and other angiosperm plants. ANNALS OF BOTANY 2014; 113:1083-1105. [PMID: 24825294 PMCID: PMC4030820 DOI: 10.1093/aob/mcu065] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 03/06/2014] [Indexed: 05/23/2023]
Abstract
BACKGROUND Asymmetric cell divisions are formative divisions that generate daughter cells of distinct identity. These divisions are coordinated by either extrinsic ('niche-controlled') or intrinsic regulatory mechanisms and are fundamentally important in plant development. SCOPE This review describes how asymmetric cell divisions are regulated during development and in different cell types in both the root and the shoot of plants. It further highlights ways in which omics and modelling approaches have been used to elucidate these regulatory mechanisms. For example, the regulation of embryonic asymmetric divisions is described, including the first divisions of the zygote, formative vascular divisions and divisions that give rise to the root stem cell niche. Asymmetric divisions of the root cortex endodermis initial, pericycle cells that give rise to the lateral root primordium, procambium, cambium and stomatal cells are also discussed. Finally, a perspective is provided regarding the role of other hormones or regulatory molecules in asymmetric divisions, the presence of segregated determinants and the usefulness of modelling approaches in understanding network dynamics within these very special cells. CONCLUSIONS Asymmetric cell divisions define plant development. High-throughput genomic and modelling approaches can elucidate their regulation, which in turn could enable the engineering of plant traits such as stomatal density, lateral root development and wood formation.
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Affiliation(s)
- Kaisa Kajala
- Department of Plant Biology and Genome Center, UC Davis, Davis, CA 95616, USA
| | - Priya Ramakrishna
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, UK
| | - Adam Fisher
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Dominique C. Bergmann
- Howard Hughes Medical Institute and Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Ive De Smet
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, UK
- Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052 Ghent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, Technologiepark 927, B-9052 Ghent, Belgium
| | - Rosangela Sozzani
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703HA Wageningen, The Netherlands
| | - Siobhan M. Brady
- Department of Plant Biology and Genome Center, UC Davis, Davis, CA 95616, USA
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19
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Costa LM, Marshall E, Tesfaye M, Silverstein KAT, Mori M, Umetsu Y, Otterbach SL, Papareddy R, Dickinson HG, Boutiller K, VandenBosch KA, Ohki S, Gutierrez-Marcos JF. Central Cell-Derived Peptides Regulate Early Embryo Patterning in Flowering Plants. Science 2014; 344:168-72. [DOI: 10.1126/science.1243005] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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20
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Abstract
During early embryogenesis, flowering plants establish their principal body plan starting with an apical–basal axis. An asymmetric division of the zygote gives rise to apical and basal cells with different developmental fates. Besides WOX (WUSCHEL-RELATED HOMEOBOX) transcription factors and the plant hormone auxin, the YDA (YODA)/MAPK (mitogen-activated protein kinase) pathway plays a major role in establishing different cell fates after the first zygotic division. In the present review, we summarize the available data on YDA signalling during embryogenesis. The role of YDA in other developmental processes was taken into account to highlight possible implications for this pathway in the embryo.
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21
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Marzec M, Melzer M, Szarejko I. The evolutionary context of root epidermis cell patterning in grasses (Poaceae). PLANT SIGNALING & BEHAVIOR 2014; 9:e27972. [PMID: 24521825 PMCID: PMC4091389 DOI: 10.4161/psb.27972] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 01/22/2014] [Accepted: 01/23/2014] [Indexed: 05/18/2023]
Abstract
In the last century, the mechanism for establishing the root epidermal pattern in grasses was proposed as a differentiating trait that can be used in taxonomic studies and as a useful tool to indicate the relationships between genera. However, knowledge about root hair differentiation in monocots is still scarce. During the last few years, this process has been studied intensively, mainly based on genetics and histological studies. A histological analysis of the root epidermis pattern composed from root hairs (trichoblasts) and non-root hair cells (atrichoblasts), as well as observations of the mechanism of the establishment of this pattern allowed 2 different methods of epidermal cell specialization in monocots to be precisely described. Additionally, a recently published paper describing root hair development in barley shed new light on the evolutionary context of the mechanism of root epidermis cell specialization, which is discussed in the presented work.
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Affiliation(s)
- Marek Marzec
- Department of Genetics; Faculty of Biology and Environmental Protection; University of Silesia; Katowice, Poland
- Correspondence to: Marek Marzec,
| | - Michael Melzer
- Department of Physiology and Cell Biology; Leibniz Institute of Plant Genetics and Crop Plant Research (IPK); Gatersleben, Germany
| | - Iwona Szarejko
- Department of Genetics; Faculty of Biology and Environmental Protection; University of Silesia; Katowice, Poland
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22
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Luo A, Shi C, Zhang L, Sun MX. The expression and roles of parent-of-origin genes in early embryogenesis of angiosperms. FRONTIERS IN PLANT SCIENCE 2014; 5:729. [PMID: 25566300 PMCID: PMC4267172 DOI: 10.3389/fpls.2014.00729] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/01/2014] [Indexed: 05/03/2023]
Abstract
Uniparental transcripts during embryogenesis may arise due to gamete delivery during fertilization or genomic imprinting. Such transcripts have been found in a number of plant species and appear critical for the early development of embryo or endosperm in seeds. Although the regulatory expression mechanism and function of these genes in embryogenesis require further elucidation, recent studies suggest stage-specific and highly dynamic features that might be essential for critical developmental events such as zygotic division and cell fate determination during embryogenesis. Here, we summarize the current work in this field and discuss future research directions.
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Affiliation(s)
- An Luo
- State Key Laboratory of Hybrid Rice, Department of Cell and Developmental Biology, College of Life Sciences, Wuhan UniversityWuhan, China
- College of Life Sciences, Yangtze UniversityJingzhou, China
| | - Ce Shi
- State Key Laboratory of Hybrid Rice, Department of Cell and Developmental Biology, College of Life Sciences, Wuhan UniversityWuhan, China
| | - Liyao Zhang
- State Key Laboratory of Hybrid Rice, Department of Cell and Developmental Biology, College of Life Sciences, Wuhan UniversityWuhan, China
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, Department of Cell and Developmental Biology, College of Life Sciences, Wuhan UniversityWuhan, China
- *Correspondence: Meng-Xiang Sun, State Key Laboratory of Hybrid Rice, Department of Cell and Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, Hubei, China e-mail:
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23
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Robert HS, Grones P, Stepanova AN, Robles LM, Lokerse AS, Alonso JM, Weijers D, Friml J. Local auxin sources orient the apical-basal axis in Arabidopsis embryos. Curr Biol 2013; 23:2506-12. [PMID: 24291089 DOI: 10.1016/j.cub.2013.09.039] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 08/06/2013] [Accepted: 09/18/2013] [Indexed: 11/16/2022]
Abstract
Establishment of the embryonic axis foreshadows the main body axis of adults both in plants and in animals, but underlying mechanisms are considered distinct. Plants utilize directional, cell-to-cell transport of the growth hormone auxin to generate an asymmetric auxin response that specifies the embryonic apical-basal axis. The auxin flow directionality depends on the polarized subcellular localization of PIN-FORMED (PIN) auxin transporters. It remains unknown which mechanisms and spatial cues guide cell polarization and axis orientation in early embryos. Herein, we provide conceptually novel insights into the formation of embryonic axis in Arabidopsis by identifying a crucial role of localized tryptophan-dependent auxin biosynthesis. Local auxin production at the base of young embryos and the accompanying PIN7-mediated auxin flow toward the proembryo are required for the apical auxin response maximum and the specification of apical embryonic structures. Later in embryogenesis, the precisely timed onset of localized apical auxin biosynthesis mediates PIN1 polarization, basal auxin response maximum, and specification of the root pole. Thus, the tight spatiotemporal control of distinct local auxin sources provides a necessary, non-cell-autonomous trigger for the coordinated cell polarization and subsequent apical-basal axis orientation during embryogenesis and, presumably, also for other polarization events during postembryonic plant life.
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Affiliation(s)
- Hélène S Robert
- Mendel Centre for Genomics and Proteomics of Plants Systems, Central European Institute of Technology (CEITEC), Masaryk University, 625 00 Brno, Czech Republic; Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB) and Department of Plant Biotechnology and Genetics, Ghent University, 9052 Gent, Belgium
| | - Peter Grones
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB) and Department of Plant Biotechnology and Genetics, Ghent University, 9052 Gent, Belgium; Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Anna N Stepanova
- Department of Genetics, North Carolina State University, Raleigh, NC 27695, USA
| | - Linda M Robles
- Department of Genetics, North Carolina State University, Raleigh, NC 27695, USA
| | - Annemarie S Lokerse
- Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, the Netherlands
| | - Jose M Alonso
- Department of Genetics, North Carolina State University, Raleigh, NC 27695, USA
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, the Netherlands
| | - Jiří Friml
- Mendel Centre for Genomics and Proteomics of Plants Systems, Central European Institute of Technology (CEITEC), Masaryk University, 625 00 Brno, Czech Republic; Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB) and Department of Plant Biotechnology and Genetics, Ghent University, 9052 Gent, Belgium; Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria.
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24
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Leljak-Levanić D, Juranić M, Sprunck S. De novo zygotic transcription in wheat (Triticum aestivum L.) includes genes encoding small putative secreted peptides and a protein involved in proteasomal degradation. PLANT REPRODUCTION 2013; 26:267-85. [PMID: 23912470 DOI: 10.1007/s00497-013-0229-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 07/10/2013] [Indexed: 05/12/2023]
Abstract
Wheat is one of the world's most important crops, and increasing grain yield is a major challenge for the future. Still, our knowledge about the molecular machineries responsible for early post-fertilization events such as zygotic reprogramming, the initial cell-specification events during embryogenesis, and the intercellular communication between the early embryo and the developing endosperm is very limited. Here, we describe the identification of de novo transcribed genes in the wheat zygote. We used wheat ovaries of defined post-fertilization stages to isolate zygotes and early embryos, and identified genes that are specifically induced in these particular stages. Importantly, we observed that some of the zygotic-induced genes encode proteins with similarity to secreted signaling peptides such as TAPETUM DETERMINANT 1 and EGG APPARATUS 1, and to MATH-BTB proteins which are known substrate-binding adaptors for the Cullin3-based ubiquitin E3 ligase. This suggests that both cell-cell signaling and targeted proteasomal degradation may be important molecular events during zygote formation and the progression of early embryogenesis.
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Affiliation(s)
- Dunja Leljak-Levanić
- Department of Molecular Biology, Faculty of Science and Mathematics, University of Zagreb, Horvatovac 102a, 10000, Zagreb, Croatia
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25
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Soriano M, Li H, Boutilier K. Microspore embryogenesis: establishment of embryo identity and pattern in culture. PLANT REPRODUCTION 2013; 26:181-196. [PMID: 23852380 DOI: 10.1007/s00497-013-0226-227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 06/25/2013] [Indexed: 05/20/2023]
Abstract
The developmental plasticity of plants is beautifully illustrated by the competence of the immature male gametophyte to change its developmental fate from pollen to embryo development when exposed to stress treatments in culture. This process, referred to as microspore embryogenesis, is widely exploited in plant breeding, but also provides a unique system to understand totipotency and early cell fate decisions. We summarize the major concepts that have arisen from decades of cell and molecular studies on microspore embryogenesis and put these in the context of recent experiments, as well as results obtained from the study of pollen and zygotic embryo development.
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Affiliation(s)
- Mercedes Soriano
- Plant Research International, P.O. Box 619, 6700 AP, Wageningen, The Netherlands
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26
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Soriano M, Li H, Boutilier K. Microspore embryogenesis: establishment of embryo identity and pattern in culture. PLANT REPRODUCTION 2013; 26:181-96. [PMID: 23852380 PMCID: PMC3747321 DOI: 10.1007/s00497-013-0226-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 06/25/2013] [Indexed: 05/19/2023]
Abstract
The developmental plasticity of plants is beautifully illustrated by the competence of the immature male gametophyte to change its developmental fate from pollen to embryo development when exposed to stress treatments in culture. This process, referred to as microspore embryogenesis, is widely exploited in plant breeding, but also provides a unique system to understand totipotency and early cell fate decisions. We summarize the major concepts that have arisen from decades of cell and molecular studies on microspore embryogenesis and put these in the context of recent experiments, as well as results obtained from the study of pollen and zygotic embryo development.
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Affiliation(s)
- Mercedes Soriano
- Plant Research International, P.O. Box 619, 6700 AP Wageningen, The Netherlands
| | - Hui Li
- Plant Research International, P.O. Box 619, 6700 AP Wageningen, The Netherlands
| | - Kim Boutilier
- Plant Research International, P.O. Box 619, 6700 AP Wageningen, The Netherlands
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27
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Wendrich JR, Weijers D. The Arabidopsis embryo as a miniature morphogenesis model. THE NEW PHYTOLOGIST 2013; 199:14-25. [PMID: 23590679 DOI: 10.1111/nph.12267] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 03/12/2013] [Indexed: 05/06/2023]
Abstract
Four basic ingredients of morphogenesis, oriented cell division and expansion, cell-cell communication and cell fate specification allow plant cells to develop into a wide variety of organismal architectures. A central question in plant biology is how these cellular processes are regulated and orchestrated. Here, we present the advantages of the early Arabidopsis embryo as a model for studying the control of morphogenesis. All ingredients of morphogenesis converge during embryogenesis, and the highly predictable nature of embryo development offers unprecedented opportunities for understanding their regulation in time and space. In this review we describe the morphogenetic principles underlying embryo patterning and discuss recent advances in their regulation. Morphogenesis is under tight transcriptional control and most genes that were identified as important regulators of embryo patterning encode transcription factors or components of signaling pathways. There exists, therefore, a large gap between the transcriptional control of embryo morphogenesis and the cellular execution. We describe the first such connections, and propose future directions that should help bridge this gap and generate comprehensive understanding of the control of morphogenesis.
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Affiliation(s)
- Jos R Wendrich
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703HA, Wageningen, the Netherlands
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703HA, Wageningen, the Netherlands
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28
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Juranić M, Srilunchang KO, Krohn NG, Leljak-Levanić D, Sprunck S, Dresselhaus T. Germline-specific MATH-BTB substrate adaptor MAB1 regulates spindle length and nuclei identity in maize. THE PLANT CELL 2012; 24:4974-91. [PMID: 23250449 PMCID: PMC3556970 DOI: 10.1105/tpc.112.107169] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 11/05/2012] [Accepted: 11/28/2012] [Indexed: 05/03/2023]
Abstract
Germline and early embryo development constitute ideal model systems to study the establishment of polarity, cell identity, and asymmetric cell divisions (ACDs) in plants. We describe here the function of the MATH-BTB domain protein MAB1 that is exclusively expressed in the germ lineages and the zygote of maize (Zea mays). mab1 (RNA interference [RNAi]) mutant plants display chromosome segregation defects and short spindles during meiosis that cause insufficient separation and migration of nuclei. After the meiosis-to-mitosis transition, two attached nuclei of similar identity are formed in mab1 (RNAi) mutants leading to an arrest of further germline development. Transient expression studies of MAB1 in tobacco (Nicotiana tabacum) Bright Yellow-2 cells revealed a cell cycle-dependent nuclear localization pattern but no direct colocalization with the spindle apparatus. MAB1 is able to form homodimers and interacts with the E3 ubiquitin ligase component Cullin 3a (CUL3a) in the cytoplasm, likely as a substrate-specific adapter protein. The microtubule-severing subunit p60 of katanin was identified as a candidate substrate for MAB1, suggesting that MAB1 resembles the animal key ACD regulator Maternal Effect Lethal 26 (MEL-26). In summary, our findings provide further evidence for the importance of posttranslational regulation for asymmetric divisions and germline progression in plants and identified an unstable key protein that seems to be involved in regulating the stability of a spindle apparatus regulator(s).
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Affiliation(s)
- Martina Juranić
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany
- Department of Molecular Biology, Faculty of Science and Mathematics, University of Zagreb, 10000 Zagreb, Croatia
| | | | - Nádia Graciele Krohn
- Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirao Preto 14040-903, Brazil
| | - Dunja Leljak-Levanić
- Department of Molecular Biology, Faculty of Science and Mathematics, University of Zagreb, 10000 Zagreb, Croatia
| | - Stefanie Sprunck
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany
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29
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Ueda M, Laux T. The origin of the plant body axis. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:578-84. [PMID: 22921364 DOI: 10.1016/j.pbi.2012.08.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/01/2012] [Accepted: 08/07/2012] [Indexed: 05/11/2023]
Abstract
During embryogenesis, the basic body plan of an organism develops from a unicellular zygote. In most flowering plants, the polar zygote divides asymmetrically, making visible the apical-basal axis in the early embryo. The molecular mechanisms governing how the zygote polarizes and how this polarity is linked to embryo axis formation have been obscure, mainly owing to the difficulties to access the zygote that is deeply embedded in the maternal tissue. In this review, we summarize recent findings identifying key regulators in Arabidopsis and developing novel approaches in various plant species, which altogether set the stage for unraveling embryo axis formation.
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Affiliation(s)
- Minako Ueda
- Laboratory of Plant Growth Regulation, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Takayamacho 8916-5, Ikoma, Nara 630-0192, Japan.
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30
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Gu XL, Wang H, Huang H, Cui XF. SPT6L encoding a putative WG/GW-repeat protein regulates apical-basal polarity of embryo in Arabidopsis. MOLECULAR PLANT 2012; 5:249-259. [PMID: 21948524 DOI: 10.1093/mp/ssr073] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In eukaryotes, a protein motif consisting of WG/GW repeats, also called the Argonaute (AGO) hook, is thought to be essential for binding AGO proteins to fulfill their functions in RNA-mediated gene silencing. Although a number of WG/GW-containing proteins have been computationally identified in Arabidopsis, their roles in plant growth and development are unknown. Here, we show that the Arabidopsis Suppressor of Ty insertion 6-like (SPT6L) gene, which encodes a protein with C-terminal WG/GW repeats, plays critical roles in embryonic development. SPT6L is evolutionarily conserved only in vascular plants, with varying numbers of C-terminal WG/GW repeats, which are plant-species specific. spt6l mutants formed embryos with an aberrant apical-basal axis, showing insufficient development of the basal domain and embryonic lethality. Expression domains of the class-III homeodomain-leucine zipper (HD-ZIP III) genes PHABULOSA (PHB) and PHAVOLUTA (PHV) were expanded in the spt6l embryo. In contrast, the PLETHORA1 (PLT1) gene, which acts antagonistically to the HD-ZIP III genes in specification of basal fate, was severely down-regulated in the spt6l mutant. Furthermore, the phb phv double mutations partially rescued aberrant basal development in the spt6l background and restored PLT1 expression. Collectively, our results indicate that SPT6L is essential for specification of the apical-basal axis, partly by controlling the HD-ZIP III genes in embryos.
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Affiliation(s)
- Xiao-Lu Gu
- National Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
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31
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Plant germline development: a tale of cross-talk, signaling, and cellular interactions. ACTA ACUST UNITED AC 2011; 24:91-5. [PMID: 21590362 DOI: 10.1007/s00497-011-0170-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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32
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Boscá S, Knauer S, Laux T. Embryonic development in Arabidopsis thaliana: from the zygote division to the shoot meristem. FRONTIERS IN PLANT SCIENCE 2011; 2:93. [PMID: 22639618 PMCID: PMC3355580 DOI: 10.3389/fpls.2011.00093] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 11/20/2011] [Indexed: 05/19/2023]
Abstract
Postembryonic organ formation of plants is fueled with cells from the stem cell niches in the shoot and root meristems. During the last two decades many players that regulate stem cell maintenance have been identified. With these factors in hand, the mechanisms establishing stem cell niches during embryo development can be addressed. Here we discuss current models of how the shoot meristem stem cell niche arises during Arabidopsis embryo pattern formation.
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Affiliation(s)
- Sonia Boscá
- Faculty of Biology, BIOSS Centre for Biological Signalling Studies, University of FreiburgFreiburg, Germany
| | - Steffen Knauer
- Faculty of Biology, BIOSS Centre for Biological Signalling Studies, University of FreiburgFreiburg, Germany
| | - Thomas Laux
- Faculty of Biology, BIOSS Centre for Biological Signalling Studies, University of FreiburgFreiburg, Germany
- *Correspondence: Thomas Laux, Faculty of Biology, BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg, Germany. e-mail:
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