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Cell lineage-specific transcriptome analysis for interpreting cell fate specification of proembryos. Nat Commun 2020; 11:1366. [PMID: 32170064 PMCID: PMC7070050 DOI: 10.1038/s41467-020-15189-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/24/2020] [Indexed: 12/17/2022] Open
Abstract
In Arabidopsis, a zygote undergoes asymmetrical cell division that establishes the first two distinct cell types of early proembryos, apical and basal cells. However, the genome-wide transcriptional activities that guide divergence of apical and basal cell development remain unknown. Here, we present a comprehensive transcriptome analysis of apical and basal cell lineages, uncovering distinct molecular pathways during cell lineage specification. Selective deletion of inherited transcripts and specific de novo transcription contribute to the establishment of cell lineage-specific pathways for cell fate specification. Embryo-related pathways have been specifically activated in apical cell lineage since 1-cell embryo stage, but quick transcriptome remodeling toward suspensor-specific pathways are found in basal cell lineage. Furthermore, long noncoding RNAs and alternative splicing isoforms may be involved in cell lineage specification. This work also provides a valuable lineage-specific transcriptome resource to elucidate the molecular pathways for divergence of apical and basal cell lineages at genome-wide scale. Asymmetric division of the Arabidopsis zygote produces apical and basal cells that mainly develop into embryo and suspensor, respectively. Here, Zhou et al. show that de novo transcription and selective RNA turnover establish distinct apical and basal transcriptomes as early as the 1-cell stage of embryo development.
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Zhou X, Shi C, Zhao P, Sun M. Isolation of living apical and basal cell lineages of early proembryos for transcriptome analysis. PLANT REPRODUCTION 2019; 32:105-111. [PMID: 30547251 DOI: 10.1007/s00497-018-00353-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 11/24/2018] [Indexed: 06/09/2023]
Abstract
Plant zygotes usually undergo asymmetrical cell division, giving rise to the formation of two daughter cells with distinct developmental cell fate. The small apical cell will develop into the major part of embryo proper, whereas the larger basal cell will divide to form a transient suspensor. Thus, the apical and basal cell lineages are an excellent model to study cell fate determination in relation to zygote polarity. However, the molecular mechanism underlying the differentiation of two distinct cell lineages is not yet understood, possibly due to the technique limitations. Previously, we have established a protocol for isolating apical cell and basal cell for cDNA library construction in tobacco. However, the method for isolating tiny Arabidopsis embryos has long been considered much more difficult. Here, we present a detailed protocol for isolating early Arabidopsis proembryos and separating apical and basal cell lineages of proembryos, which allow us to establish cell lineage-specific transcriptomes of early proembryos.
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Affiliation(s)
- Xuemei Zhou
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Ce Shi
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
| | - Mengxiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
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Dresselhaus T, Weijers D. Special issue: cellular omics methods in plant reproduction research. PLANT REPRODUCTION 2019; 32:1-3. [PMID: 30805715 DOI: 10.1007/s00497-019-00366-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708WE, Wageningen, The Netherlands.
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Wang W, Zhou XM, Xiong HX, Mao WY, Zhao P, Sun MX. Papain-like and legumain-like proteases in rice: genome-wide identification, comprehensive gene feature characterization and expression analysis. BMC PLANT BIOLOGY 2018; 18:87. [PMID: 29764367 PMCID: PMC5952849 DOI: 10.1186/s12870-018-1298-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 04/26/2018] [Indexed: 05/23/2023]
Abstract
BACKGROUND Papain-like and legumain-like proteases are proteolytic enzymes which play key roles in plant development, senescence and defense. The activities of proteases in both families could be inhibited by a group of small proteins called cystatin. Cystatin family genes have been well characterized both in tobacco and rice, suggesting their potential roles in seed development. However, their potential targets, papain-like and legumain-like proteases, have not been well characterized in plants, especially in rice, a model plant for cereal biology. RESULTS Here, 33 papain-like and 5 legumain-like proteases have been identified in rice genome, respectively. Gene structure, distribution in rice chromosome, and evolutionary relationship to their counterparts in other plants have been well characterized. Comprehensive expression profile analysis revealed that two family genes display divergent expression pattern, which are regulated temporally and spatially during the process of seed development and germination. Our experiments also revealed that the expression of most genes in these two families is sensitively responsive to plant hormones and different abiotic stresses. CONCLUSIONS Genome-wide identification and comprehensive gene expression pattern analysis of papain-like and legumain-like proteases in rice suggests their multiple and cooperative roles in seed development and response to environmental variations, which provides several useful cues for further in-depth study.
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Affiliation(s)
- Wei Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Xue-Mei Zhou
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Han-Xian Xiong
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Wan-Ying Mao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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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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Zhou X, Guo Y, Zhao P, Sun MX. Comparative Analysis of WUSCHEL-Related Homeobox Genes Revealed Their Parent-of-Origin and Cell Type-Specific Expression Pattern During Early Embryogenesis in Tobacco. FRONTIERS IN PLANT SCIENCE 2018; 9:311. [PMID: 29662495 PMCID: PMC5890105 DOI: 10.3389/fpls.2018.00311] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 02/22/2018] [Indexed: 05/05/2023]
Abstract
WUSCHEL-related homeobox (WOX) gene is a plant-specific clade of homeobox transcription factors. Increasing evidences reveal that WOXs play critical roles in early embryogenesis, which involves zygote development, initiation of zygote division, and apical or basal cell lineage establishment. However, how WOXs regulate these developmental events remains largely unknown, and even detailed expression pattern in gametes and early proembryos is not yet available. Here, 13 WOX family genes were identified in Nicotiana tabacum genome. Comparative analysis of 13 WOX family genes with their homologs in Arabidopsis thaliana reveals relatively conserved expression pattern of WUS and WOX5 in shoot/root apical meristem. Whereas variations were also found, e.g., lacking homolog of WOX8 (a marker for suspensor cell) in tobacco genome and the expression of WOX2/WOX9 in both apical cell and basal cell. Transient transcriptional activity analysis revealed that WOXs in WUS clade have repressive activities for their target's transcription, whereas WOXs in ancient and intermediate clade have activation activities, giving a molecular basis for the phylogenetic classification of tobacco WOXs into three major clades. Expression pattern analysis revealed that some WOXs (e.g., WOX 13a) expressed in both male and female gametes and some WOXs (e.g., WOX 11 and WOX 13b) displayed the characteristics of parent-of-origin genes. Interestingly, some WOXs (e.g., WOX2 and WOX9), which are essential for early embryo patterning, were de novo transcribed in zygote, indicating relevant mechanism for embryo pattern formation is only established in zygote right after fertilization and not carried in by gametes. We also found that most WOXs displayed a stage-specific and cell type-specific expression pattern. Taken together, this work provides a detailed landscape of WOXs in tobacco during fertilization and early embryogenesis, which will facilitate the understanding of their specific roles in these critical developmental processes of embryogenesis.
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Qu LH, Zhou X, Li X, Li SS, Zhao J, Zhao P, Liu Y, Sun MX. The autonomous cell fate specification of basal cell lineage: the initial round of cell fate specification occurs at the two-celled proembryo stage. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:1051-1063. [PMID: 28671744 DOI: 10.1111/tpj.13629] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 06/16/2017] [Accepted: 06/23/2017] [Indexed: 06/07/2023]
Abstract
In angiosperms, the first zygotic division usually gives rise to two daughter cells with distinct morphologies and developmental fates, which is critical for embryo pattern formation; however, it is still unclear when and how these distinct cell fates are specified, and whether the cell specification is related to cytoplasmic localization or polarity. Here, we demonstrated that when isolated from both maternal tissues and the apical cell, a single basal cell could only develop into a typical suspensor, but never into an embryo in vitro. Morphological, cytological and gene expression analyses confirmed that the resulting suspensor in vitro is highly similar to its undisturbed in vivo counterpart. We also demonstrated that the isolated apical cell could develop into a small globular embryo, both in vivo and in vitro, after artificial dysfunction of the basal cell; however, these growing apical cell lineages could never generate a new suspensor. These findings suggest that the initial round of cell fate specification occurs at the two-celled proembryo stage, and that the basal cell lineage is autonomously specified towards the suspensor, implying a polar distribution of cytoplasmic contents in the zygote. The cell fate transition of the basal cell lineage to the embryo in vivo is actually a conditional cell specification process, depending on the developmental signals from both the apical cell lineage and maternal tissues connected to the basal cell lineage.
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Affiliation(s)
- Liang-Huan Qu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xuemei Zhou
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Xinbo Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Shi-Sheng Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Jing Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Yuan Liu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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Zhao P, Begcy K, Dresselhaus T, Sun MX. Does Early Embryogenesis in Eudicots and Monocots Involve the Same Mechanism and Molecular Players? PLANT PHYSIOLOGY 2017; 173:130-142. [PMID: 27909044 PMCID: PMC5210740 DOI: 10.1104/pp.16.01406] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/30/2016] [Indexed: 05/18/2023]
Abstract
A comparison of eudicot and monocot model plants explores recent advances and open questions on gene regulatory networks during zygote development, parental influences on early embryogenesis, zygotic genome activation, and cell fate determination.
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Affiliation(s)
- Peng Zhao
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China (P.Z., M.-X.S.); and
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany (K.B., T.D.)
| | - Kevin Begcy
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China (P.Z., M.-X.S.); and
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany (K.B., T.D.)
| | - Thomas Dresselhaus
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China (P.Z., M.-X.S.); and
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany (K.B., T.D.)
| | - Meng-Xiang Sun
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China (P.Z., M.-X.S.); and
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany (K.B., T.D.)
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9
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Zhao J, Sun MX. Asymmetric zygote division: A mystery starting point of embryogenesis. PLANT SIGNALING & BEHAVIOR 2016; 11:e1238546. [PMID: 27662512 PMCID: PMC5257166 DOI: 10.1080/15592324.2016.1238546] [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: 09/06/2016] [Revised: 09/08/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
In angiosperm, asymmetric zygote division is critical for embryogenesis. The molecular mechanism underlying this process has gained a great attention recently. Some players involve in the control of both accurate position and correct orientation of zygote division plane have been found, which provide useful clues for the extensive investigations. It is getting clear that both internal and external factors are involved in this complex regulatory mechanism and the asymmetric zygote division seems with great impact in cell fate determination and embryo pattern formation.
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Affiliation(s)
- Jing Zhao
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, China
| | - Meng-Xiang Sun
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, China
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10
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Wang W, Zhao P, Zhou XM, Xiong HX, Sun MX. Genome-wide identification and characterization of cystatin family genes in rice (Oryza sativa L.). PLANT CELL REPORTS 2015; 34:1579-92. [PMID: 26007238 DOI: 10.1007/s00299-015-1810-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 05/04/2015] [Accepted: 05/13/2015] [Indexed: 05/26/2023]
Abstract
11 Cystatin genes in rice were identified, and their expression patterns were comprehensively analyzed, which reveals multiple roles in both seed development and plant response to environmental variations. Cystatin is a group of small proteins and known to inhibit the activities of cysteine proteases in the papain C1A and legumain C13 peptidase families in plants. Cystatin family genes have only been well characterized recently in a few plant species such as Hordeum vulgare and Nicotiana tabacum, which show their critical roles in programmed cell death and responses to biotic stresses. Up to now, little is known about cystatin family genes and their roles in Oryza sativa, a model plant for cereal biology study. Here, we identified 11 cystatin genes in rice genome. Comprehensive expression profile analysis reveals that cystatin family genes in rice display diverse expression pattern. They are temporally regulated at different developmental stages during the process of seed production and germination. Our experiments also reveal that the majority of cystatin genes are responsive to plant hormones and different environmental cues including cold, drought and other abiotic stresses, while some others are very stable under different stresses, indicating their fundamental roles in normal plant development. In addition, their distribution in rice chromosomes and their evolutionary relation to the members of Cystatin family in A. thaliana and N. tabacum have also been analyzed. These works suggest multiple roles of cystatin family genes in both seed development and plant response to environmental variations.
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Affiliation(s)
- Wei Wang
- State Key Laboratory of Hybrid Rice, Department of Cell and Developmental Biology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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11
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Zhao P, Sun MX. The Maternal-to-Zygotic Transition in Higher Plants: Available Approaches, Critical Limitations, and Technical Requirements. Curr Top Dev Biol 2015; 113:373-98. [PMID: 26358879 DOI: 10.1016/bs.ctdb.2015.06.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Fertilization marks the turnover from the gametophyte to sporophyte generation in higher plants. After fertilization, sporophytic development undergoes genetic turnover from maternal to zygotic control: the maternal-to-zygotic transition (MZT). The MZT is thought to be critical for early embryogenesis; however, little is known about the time course or developmental impact of the MZT in higher plants. Here, we discuss what is known in the field and focus on techniques used in relevant studies and their limitations. Some significant questions and technical requirements for further investigations are also discussed.
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Affiliation(s)
- Peng Zhao
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, China
| | - Meng-Xiang Sun
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, China.
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12
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Kuang Q, Yu X, Peng X, Sun MX. The isolation of early nuclear endosperm of Oryza sativa to facilitate gene expression analysis and screening imprinted genes. PLANT METHODS 2015; 11:49. [PMID: 26500689 PMCID: PMC4618753 DOI: 10.1186/s13007-015-0092-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 10/13/2015] [Indexed: 05/16/2023]
Abstract
BACKGROUND Since the quality and yield of rice production depends on endosperm development, previous studies have focused on the molecular mechanism that regulates this developmental process. Recently, how this process is epigenetically regulated has become an important topic. However, the gene expression analysis and screening imprinted genes during early endosperm development remain challenging since the isolation of early endosperm has not been possible. Here, we report a procedure for the isolation of endosperm at 24 or 48 HAP (hours after pollination) during the free nuclear stage of endosperm development. RESULTS This technique allows for rapid and convenient collection of pure free nuclear endosperm. Early endosperm RNA can then be extracted from the isolated endosperm cells using dynabeads. Our results showed that the quality of RNA is satisfactory for gene expression analysis and screening the parental-of-origin specific genes in early endosperm. CONCLUSIONS Thus, we offer a reliable method to overcome one of the major obstacles in the investigation of the molecular mechanisms of early endosperm development. Our approach can be used for accurate gene expression analysis and screening of imprinted genes, and facilitates the confirmation of endosperm-specific gene expression at the very early stages of endosperm development. This method could also be used in other species to collect early free nuclear endosperm.
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Affiliation(s)
- Quan Kuang
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072 China
| | - Xiaobo Yu
- 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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Zhao P, Zhou XM, Zou J, Wang W, Wang L, Peng XB, Sun MX. Comprehensive analysis of cystatin family genes suggests their putative functions in sexual reproduction, embryogenesis, and seed formation. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:5093-107. [PMID: 24996653 PMCID: PMC4144781 DOI: 10.1093/jxb/eru274] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Cystatins are tightly bound and reversible inhibitors of cysteine proteases in C1A and C13 peptidase families, which have been identified in several species and shown to function in vegetative development and response to biotic/abiotic stresses in plants. Recent work revealed their critical role in regulating programmed cell death during embryogenesis in tobacco and suggested their more comprehensive roles in the process of sexual plant reproduction, although little is known about cystatin family genes in the processes. Here, 10 cystatin family genes in Nicotiana tabacum were identified using an expressed sequence tag (EST)-based gene clone strategy. Analysis of their biochemical properties showed that nine of them have the potency to inhibit the activities of both commercial cathepsin L-like proteases and extracted cysteine proteases from seeds, but with different K i values depending on the types of proteases and the developmental stages of the seed tested. This suggests that cystatin-dependent cathepsin L-like proteolytic pathways are probably important for early seed development. Comprehensive expression profile analysis revealed that cystatin family genes showed manifold variations in their transcription levels in different plant cell types, including the sperm, egg, and zygote, especially in the embryo and seed at different developmental stages. More interestingly, intracellular localization analysis of each cystatin revealed that most members of cystatin families are recognized as secretory proteins with signal peptides that direct them to the endoplasmic reticulum. These results suggest their widespread roles in cell fate determination and cell-cell communication in the process of sexual reproduction, especially in gamete and embryo development, as well as in seed formation.
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Affiliation(s)
- Peng Zhao
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Plant Hybrid rice, Wuhan University, Wuhan 430072, China
| | - Xue-mei Zhou
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Plant Hybrid rice, Wuhan University, Wuhan 430072, China
| | - Jie Zou
- Molecular Genetics Key Laboratory of China Tobacco, Guizhou Academy of Tobacco Science, Guiyang 550081, China
| | - Wei Wang
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Plant Hybrid rice, Wuhan University, Wuhan 430072, China
| | - Lu Wang
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden of the Chinese Academy of Sciences, Wuhan 430074, China
| | - Xiong-bo Peng
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Plant Hybrid rice, Wuhan University, Wuhan 430072, China
| | - Meng-xiang Sun
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Plant Hybrid rice, Wuhan University, Wuhan 430072, China
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14
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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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Palovaara J, Saiga S, Weijers D. Transcriptomics approaches in the early Arabidopsis embryo. TRENDS IN PLANT SCIENCE 2013; 18:514-21. [PMID: 23726727 DOI: 10.1016/j.tplants.2013.04.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 04/24/2013] [Accepted: 04/30/2013] [Indexed: 05/20/2023]
Abstract
Early plant embryogenesis condenses the fundamental processes underlying plant development into a short sequence of predictable steps. The main tissues, as well as stem cells for their post-embryonic maintenance, are specified through genetic control networks. A key question is how cell fates are instructed by unique cellular transcriptomes, and important insights have recently been gained through cell type-specific transcriptomics during post-embryonic development. However, the poor accessibility and small size of Arabidopsis (Arabidopsis thaliana) embryos have obstructed similar progress during embryogenesis. Here, we review the current situation in plant embryo transcriptomics, and discuss how the recent development of novel cell-specific analysis technologies will enable the identification of cellular transcriptomes in the early Arabidopsis embryo.
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Affiliation(s)
- Joakim Palovaara
- Laboratory of Biochemistry, Wageningen University, The Netherlands
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Zhao P, Zhou XM, Zhang LY, Wang W, Ma LG, Yang LB, Peng XB, Bozhkov PV, Sun MX. A bipartite molecular module controls cell death activation in the Basal cell lineage of plant embryos. PLoS Biol 2013; 11:e1001655. [PMID: 24058297 PMCID: PMC3769231 DOI: 10.1371/journal.pbio.1001655] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Accepted: 08/01/2013] [Indexed: 11/19/2022] Open
Abstract
Plant zygote divides asymmetrically into an apical cell that develops into the embryo proper and a basal cell that generates the suspensor, a vital organ functioning as a conduit of nutrients and growth factors to the embryo proper. After the suspensor has fulfilled its function, it is removed by programmed cell death (PCD) at the late stages of embryogenesis. The molecular trigger of this PCD is unknown. Here we use tobacco (Nicotiana tabacum) embryogenesis as a model system to demonstrate that the mechanism triggering suspensor PCD is based on the antagonistic action of two proteins: a protease inhibitor, cystatin NtCYS, and its target, cathepsin H-like protease NtCP14. NtCYS is expressed in the basal cell of the proembryo, where encoded cystatin binds to and inhibits NtCP14, thereby preventing precocious onset of PCD. The anti-cell death effect of NtCYS is transcriptionally regulated and is repressed at the 32-celled embryo stage, leading to increased NtCP14 activity and initiation of PCD. Silencing of NtCYS or overexpression of NtCP14 induces precocious cell death in the basal cell lineage causing embryonic arrest and seed abortion. Conversely, overexpression of NtCYS or silencing of NtCP14 leads to profound delay of suspensor PCD. Our results demonstrate that NtCYS-mediated inhibition of NtCP14 protease acts as a bipartite molecular module to control initiation of PCD in the basal cell lineage of plant embryos.
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Affiliation(s)
- Peng Zhao
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Xue-mei Zhou
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Li-yao Zhang
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Wei Wang
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Li-gang Ma
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Li-bo Yang
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Xiong-bo Peng
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Peter V. Bozhkov
- Department of Plant Biology and Forest Genetics, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Meng-xiang Sun
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
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Li S, He Y, Zhao J, Zhang L, Sun MX. Polar protein transport between apical and basal cells during tobacco early embryogenesis. PLANT CELL REPORTS 2013; 32:285-91. [PMID: 23124803 DOI: 10.1007/s00299-012-1362-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 09/25/2012] [Accepted: 10/21/2012] [Indexed: 06/01/2023]
Abstract
KEY MESSAGE : We found that protein trafficking between apical and basal cell can be unidirectional, which reveals the different roles of the two cells in the cell-to-cell communication between them during early embryogenesis. In most angiosperm species, asymmetric zygote division results in an apical cell and a basal cell that have distinct cell fates. Much has been speculated about possible communication between these cell types in relation to their cell fate determination. Here, we report on the use of photoactivatable green fluorescent protein (PA-GFP) in tobacco to trace intercellular communication between apical and basal cells during early embryogenesis. We found that PA-GFP was transported between apical and basal cells of a two-celled proembryo, and that protein trafficking was unidirectional toward the apical cell, highlighting different cell communication roles. Further ultrastructural analysis showed numerous plasmodesmata in the walls connecting the apical and basal cells, which may provide channels for protein trafficking. Our data show a possible unique method of cell-to-cell communication between apical and basal cells during early embryogenesis.
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Affiliation(s)
- Shisheng Li
- State Key Laboratory of Hybrid Rice, College of Life Science, Wuhan University, Wuhan 430072, China
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Tang X, Liu Y, He Y, Ma L, Sun MX. Exine dehiscing induces rape microspore polarity, which results in different daughter cell fate and fixes the apical-basal axis of the embryo. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:215-28. [PMID: 23162119 PMCID: PMC3528033 DOI: 10.1093/jxb/ers327] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The roles of cell polarity and the first asymmetric cell division during early embryogenesis in apical-basal cell fate determination remain unclear. Previously, a novel Brassica napus microspore embryogenesis system was established, by which rape exine-dehisced microspores were induced by physical stress. Unlike traditional microspore culture, cell polarity and subsequent asymmetric division appeared in the exine-dehisced microspore, which finally developed into a typical embryo with a suspensor. Further studies indicated that polarity is critical for apical-basal cell fate determination and suspensor formation. However, the pattern of the first division was not only determined by cell polarity but was also regulated by the position of the ruptured exine. The first division could be equal or unequal, with its orientation essentially perpendicular to the polar axis. In both types of cell division, the two daughter cells could have different cell fates and give rise to an embryo with a suspensor, similar to zygotic apical-basal cell differentiation. The alignment of the two daughter cells is consistent with the orientation of the apical-basal axis of future embryonic development. Thus, the results revealed that exine dehiscing induces rape microspore polarization, and this polarity results in a different cell fate and fixes the apical-basal axis of embryogenesis, but is uncoupled from cell asymmetric division. The present study demonstrated the relationships among cell polarity, asymmetric cell division, and cell fate determination in early embryogenesis.
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Affiliation(s)
- Xingchun Tang
- Department of Cell and Developmental Biology, College of Life Science and State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
- College of Life and Science, Hubei University, Wuhan 430062, China
| | - Yuan Liu
- Department of Cell and Developmental Biology, College of Life Science and State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Yuqing He
- Department of Cell and Developmental Biology, College of Life Science and State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Ligang Ma
- Department of Cell and Developmental Biology, College of Life Science and State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Meng-xiang Sun
- Department of Cell and Developmental Biology, College of Life Science and State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
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Yu M, Zhao J. The cytological changes of tobacco zygote and proembryo cells induced by beta-glucosyl Yariv reagent suggest the involvement of arabinogalactan proteins in cell division and cell plate formation. BMC PLANT BIOLOGY 2012; 12:126. [PMID: 22853005 PMCID: PMC3487971 DOI: 10.1186/1471-2229-12-126] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 07/12/2012] [Indexed: 05/21/2023]
Abstract
BACKGROUND In dicotyledonous plant, the first asymmetric zygotic division and subsequent several cell divisions are crucial for proembryo pattern formation and later embryo development. Arabinogalactan proteins (AGPs) are a family of extensively glycosylated cell surface proteins that are thought to have important roles in various aspects of plant growth and development, including embryogenesis. Previous results from our laboratory show that AGPs are concerned with tobacco egg cell fertilization and zygotic division. However, how AGPs interact with other factors involved in zygotic division and proembryo development remains unknown. RESULTS In this study, we used the tobacco in vitro zygote culture system and series of meticulous cell biology techniques to investigate the roles of AGPs in zygote and proembryo cell division. For the first time, we examined tobacco proembryo division patterns detailed to every cell division. The bright-field images and statistical results both revealed that with the addition of an exogenous AGPs inhibitor, beta-glucosyl Yariv (beta-GlcY) reagent, the frequency of aberrant division increased remarkably in cultured tobacco zygotes and proembryos, and the cell plate specific locations of AGPs were greatly reduced after beta-GlcY treatment. In addition, the accumulations of new cell wall materials were also significantly affected by treating with beta-GlcY. Detection of cellulose components by Calcofluor white stain showed that strong fluorescence was located in the newly formed wall of daughter cells after the zygotic division of in vivo samples and the control samples from in vitro culture without beta-GlcY treatment; while there was only weak fluorescence in the newly formed cell walls with beta-GlcY treatment. Immunocytochemistry examination with JIM5 and JIM7 respectively against the low- and high-esterified pectins displayed that these two pectins located in opposite positions of zygotes and proembryos in vivo and the polarity was not affected by beta-GlcY. Furthermore, FM4-64 staining revealed that endosomes were distributed in the cell plates of proembryos, and the localization pattern was also affected by beta-GlcY treatment. These results were further confirmed by subsequent observation with transmission electron microscopy. Moreover, the changes to proembryo cell-organelles induced by beta-GlcY reagent were also observed using fluorescent dye staining technique. CONCLUSIONS These results imply that AGPs may not only relate to cell plate position decision, but also to the location of new cell wall components. Correlated with other factors, AGPs further influence the zygotic division and proembryo pattern establishment in tobacco.
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Affiliation(s)
- Miao Yu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Jie Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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Hu TX, Yu M, Zhao J. Comparative transcriptional analysis reveals differential gene expression between asymmetric and symmetric zygotic divisions in tobacco. PLoS One 2011; 6:e27120. [PMID: 22069495 PMCID: PMC3206072 DOI: 10.1371/journal.pone.0027120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 10/11/2011] [Indexed: 11/24/2022] Open
Abstract
Asymmetric cell divisions occur widely during many developmental processes in plants. In most angiosperms, the first zygotic cell division is asymmetric resulting in two daughter cells of unequal size and with distinct fates. However, the critical molecular mechanisms regulating this division remain unknown. Previously we showed that treatment of tobacco zygotes with beta-glucosyl Yariv (βGlcY) could dramatically alter the first zygotic asymmetric division to produce symmetric two-celled proembryos. In the present study, we isolated zygotes and two-celled asymmetric proembryos in vivo by micromanipulation, and obtained symmetric, two-celled proembryos by in vitro cell cultures. Using suppression-subtractive hybridization (SSH) and macroarray analysis differential gene expression between the zygote and the asymmetric and symmetric two-celled proembryos was investigated. After sequencing of the differentially expressed clones, a total of 1610 EST clones representing 685 non-redundant transcripts were obtained. Gene ontology (GO) term analysis revealed that these transcripts include those involved in physiological processes such as response to stimulus, regulation of gene expression, and localization and formation of anatomical structures. A homology search against known genes from Arabidopsis indicated that some of the above transcripts are involved in asymmetric cell division and embryogenesis. Quantitative real-time PCR confirmed the up- or down-regulation of the selected candidate transcripts during zygotic division. A few of these transcripts were expressed exclusively in the zygote, or in either type of the two-celled proembryos. Expression analyses of select genes in different tissues and organs also revealed potential roles of these transcripts in fertilization, seed maturation and organ development. The putative roles of few of the identified transcripts in the regulation of zygotic division are discussed. Further functional work on these candidate transcripts will provide important information for understanding asymmetric zygotic division, generation of apical-basal polarity and cell fate decisions during early embryogenesis.
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Affiliation(s)
- Tian-Xiang Hu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Miao Yu
- 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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