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Demesa-Arevalo E, Narasimhan M, Simon R. Intercellular Communication in Shoot Meristems. ANNUAL REVIEW OF PLANT BIOLOGY 2024; 75:319-344. [PMID: 38424066 DOI: 10.1146/annurev-arplant-070523-035342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
The shoot meristem of land plants maintains the capacity for organ generation throughout its lifespan due to a group of undifferentiated stem cells. Most meristems are shaped like a dome with a precise spatial arrangement of functional domains, and, within and between these domains, cells interact through a network of interconnected signaling pathways. Intercellular communication in meristems is mediated by mobile transcription factors, small RNAs, hormones, and secreted peptides that are perceived by membrane-localized receptors. In recent years, we have gained deeper insight into the underlying molecular processes of the shoot meristem, and we discuss here how plants integrate internal and external inputs to control shoot meristem activities.
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Affiliation(s)
- Edgar Demesa-Arevalo
- Institute for Developmental Genetics, Heinrich Heine University, Düsseldorf, Germany;
| | - Madhumitha Narasimhan
- Institute for Developmental Genetics, Heinrich Heine University, Düsseldorf, Germany;
| | - Rüdiger Simon
- Institute for Developmental Genetics, Heinrich Heine University, Düsseldorf, Germany;
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2
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Han L, Huang Y, Li C, Tian D, She D, Li M, Wang Z, Chen J, Liu L, Wang S, Song W, Wang L, Gu C, Wu T, Zhao J, Zhou Z, Zhang X. Heterotrimeric Gα-subunit regulates flower and fruit development in CLAVATA signaling pathway in cucumber. HORTICULTURE RESEARCH 2024; 11:uhae110. [PMID: 38898960 PMCID: PMC11186068 DOI: 10.1093/hr/uhae110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 04/07/2024] [Indexed: 06/21/2024]
Abstract
Flowers and fruits are the reproductive organs in plants and play essential roles in natural beauty and the human diet. CLAVATA (CLV) signaling has been well characterized as regulating floral organ development by modulating shoot apical meristem (SAM) size; however, the signaling molecules downstream of the CLV pathway remain largely unknown in crops. Here, we found that functional disruption of CsCLV3 peptide and its receptor CsCLV1 both resulted in flowers with extra organs and stumpy fruits in cucumber. A heterotrimeric G protein α-subunit (CsGPA1) was shown to interact with CsCLV1. Csgpa1 mutant plants derived from gene editing displayed significantly increased floral organ numbers and shorter and wider fruits, a phenotype resembling that of Csclv mutants in cucumber. Moreover, the SAM size was enlarged and the longitudinal cell size of fruit was decreased in Csgpa1 mutants. The expression of the classical stem cell regulator WUSCHEL (WUS) was elevated in the SAM, while the expression of the fruit length stimulator CRABS CLAW (CRC) was reduced in the fruit of Csgpa1 mutants. Therefore, the Gα-subunit CsGPA1 protein interacts with CsCLV1 to inhibit floral organ numbers but promote fruit elongation, via repressing CsWUS expression and activating CsCRC transcription in cucumber. Our findings identified a new player in the CLV signaling pathway during flower and fruit development in dicots, increasing the number of target genes for precise manipulation of fruit shape during crop breeding.
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Affiliation(s)
- Lijie Han
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Yafei Huang
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Chuang Li
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Di Tian
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Daixi She
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Min Li
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Zhongyi Wang
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Jiacai Chen
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Liu Liu
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Shaoyun Wang
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Weiyuan Song
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Liming Wang
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Chaoheng Gu
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Tao Wu
- College of Horticulture/Yuelu Mountain Laboratory of Hunan Province, Hunan Agricultural University, Changsha 410128, China
| | - Jianyu Zhao
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Zhaoyang Zhou
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Xiaolan Zhang
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
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Rambaud-Lavigne L, Chatterjee A, Bovio S, Battu V, Lavigne Q, Gundiah N, Boudaoud A, Das P. Heterogeneous identity, stiffness and growth characterise the shoot apex of Arabidopsis stem cell mutants. Development 2024; 151:dev202810. [PMID: 38752444 DOI: 10.1242/dev.202810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 05/07/2024] [Indexed: 06/11/2024]
Abstract
Stem cell homeostasis in the shoot apical meristem involves a core regulatory feedback loop between the signalling peptide CLAVATA3 (CLV3), produced in stem cells, and the transcription factor WUSCHEL, expressed in the underlying organising centre. clv3 mutant meristems display massive overgrowth, which is thought to be caused by stem cell overproliferation, although it is unknown how uncontrolled stem cell divisions lead to this altered morphology. Here, we reveal local buckling defects in mutant meristems, and use analytical models to show how mechanical properties and growth rates may contribute to the phenotype. Indeed, clv3 mutant meristems are mechanically more heterogeneous than the wild type, and also display regional growth heterogeneities. Furthermore, stereotypical wild-type meristem organisation, in which cells simultaneously express distinct fate markers, is lost in mutants. Finally, cells in mutant meristems are auxin responsive, suggesting that they are functionally distinguishable from wild-type stem cells. Thus, all benchmarks show that clv3 mutant meristem cells are different from wild-type stem cells, suggesting that overgrowth is caused by the disruption of a more complex regulatory framework that maintains distinct genetic and functional domains in the meristem.
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Affiliation(s)
- Léa Rambaud-Lavigne
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, 69364 Lyon Cedex 07, France
| | - Aritra Chatterjee
- Centre for BioSystems Science and Engineering, Indian Institute of Science, 560012 Bengaluru, India
| | - Simone Bovio
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, 69364 Lyon Cedex 07, France
- PLATIM-LyMIC, Université de Lyon, ENS de Lyon, Inserm, CNRS, SFR Biosciences US8 UAR3444, UCB Lyon 1, 69364 Lyon Cedex 07, France
| | - Virginie Battu
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, 69364 Lyon Cedex 07, France
| | - Quentin Lavigne
- Physikalisches Institut, Rheinische Friedrich-Wilhelms-Universität, 53115 Bonn, Germany
| | - Namrata Gundiah
- Department of Mechanical Engineering, Indian Institute of Science, 560012 Bengaluru, India
| | - Arezki Boudaoud
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, 69364 Lyon Cedex 07, France
| | - Pradeep Das
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, 69364 Lyon Cedex 07, France
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Wu H, Jia Y, Chen X, Jiang N, Zhang Z, Chai S. Novel Allelic Gene Variations in CmCLAVATA3 ( CmCLV3) Were Identified in a Genetic Population of Melon ( Cucumis melo L.). Int J Mol Sci 2024; 25:6011. [PMID: 38892198 PMCID: PMC11173160 DOI: 10.3390/ijms25116011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 05/20/2024] [Accepted: 05/27/2024] [Indexed: 06/21/2024] Open
Abstract
Carpel number (CN) is an important trait affecting the fruit size and shape of melon, which plays a crucial role in determining the overall appearance and market value. A unique non-synonymous single nucleotide polymorphism (SNP) in CmCLAVATA3 (CmCLV3) is responsible for the variation of CN in C. melo ssp. agrestis (hereafter agrestis), but it has been unclear in C. melo ssp. melo (hereafter melo). In this study, one major locus controlling the polymorphism of 5-CN (multi-CN) and 3-CN (normal-CN) in melo was identified using bulked segregant analysis (BSA-seq). This locus was then fine-mapped to an interval of 1.8 Mb on chromosome 12 using a segregating population containing 1451 progeny. CmCLV3 is still present in the candidate region. A new allele of CmCLV3, which contains five other nucleotide polymorphisms, including a non-synonymous SNP in coding sequence (CDS), except the SNP reported in agrestis, was identified in melo. A cis-trans test confirmed that the candidate gene, CmCLV3, contributes to the variation of CNs in melo. The qRT-PCR results indicate that there is no significant difference in the expression level of CmCLV3 in the apical stem between the multi-CN plants and the normal-CN plants. Overall, this study provides a genetic resource for melon fruit development research and molecular breeding. Additionally, it suggests that melo has undergone similar genetic selection but evolved into an independent allele.
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Affiliation(s)
| | | | | | | | | | - Sen Chai
- Engineering Laboratory of Genetic Improvement of Horticultural Crops of Shandong Province, College of Horticulture, Qingdao Agricultural University, Qingdao 266109, China; (H.W.); (Y.J.); (X.C.); (N.J.); (Z.Z.)
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5
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Chen Z, Cortes L, Gallavotti A. Genetic dissection of cis-regulatory control of ZmWUSCHEL1 expression by type B RESPONSE REGULATORS. PLANT PHYSIOLOGY 2024; 194:2240-2248. [PMID: 38060616 PMCID: PMC10980522 DOI: 10.1093/plphys/kiad652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 11/06/2023] [Indexed: 04/01/2024]
Abstract
Mutations in cis-regulatory regions play an important role in the domestication and improvement of crops by altering gene expression. However, assessing the in vivo impact of cis-regulatory elements (CREs) on transcriptional regulation and phenotypic outcomes remains challenging. Previously, we showed that the dominant Barren inflorescence3 (Bif3) mutant of maize (Zea mays) contains a duplicated copy of the homeobox transcription factor gene ZmWUSCHEL1 (ZmWUS1), named ZmWUS1-B. ZmWUS1-B is controlled by a spontaneously generated novel promoter region that dramatically increases its expression and alters patterning and development of young ears. Overexpression of ZmWUS1-B is caused by a unique enhancer region containing multimerized binding sites for type B RESPONSE REGULATORs (RRs), key transcription factors in cytokinin signaling. To better understand how the enhancer increases the expression of ZmWUS1 in vivo, we specifically targeted the ZmWUS1-B enhancer region by CRISPR-Cas9-mediated editing. A series of deletion events with different numbers of type B RR DNA binding motifs (AGATAT) enabled us to determine how the number of AGATAT motifs impacts in vivo expression of ZmWUS1-B and consequently ear development. In combination with dual-luciferase assays in maize protoplasts, our analysis reveals that AGATAT motifs have an additive effect on ZmWUS1-B expression, while the distance separating AGATAT motifs does not appear to have a meaningful impact, indicating that the enhancer activity derives from the sum of individual CREs. These results also suggest that in maize inflorescence development, there is a threshold of buffering capacity for ZmWUS1 overexpression.
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Affiliation(s)
- Zongliang Chen
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854-8020, USA
| | - Liz Cortes
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854-8020, USA
| | - Andrea Gallavotti
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854-8020, USA
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA
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Hong L, Fletcher JC. Stem Cells: Engines of Plant Growth and Development. Int J Mol Sci 2023; 24:14889. [PMID: 37834339 PMCID: PMC10573764 DOI: 10.3390/ijms241914889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 09/30/2023] [Accepted: 10/03/2023] [Indexed: 10/15/2023] Open
Abstract
The development of both animals and plants relies on populations of pluripotent stem cells that provide the cellular raw materials for organ and tissue formation. Plant stem cell reservoirs are housed at the shoot and root tips in structures called meristems, with the shoot apical meristem (SAM) continuously producing aerial leaf, stem, and flower organs throughout the life cycle. Thus, the SAM acts as the engine of plant development and has unique structural and molecular features that allow it to balance self-renewal with differentiation and act as a constant source of new cells for organogenesis while simultaneously maintaining a stem cell reservoir for future organ formation. Studies have identified key roles for intercellular regulatory networks that establish and maintain meristem activity, including the KNOX transcription factor pathway and the CLV-WUS stem cell feedback loop. In addition, the plant hormones cytokinin and auxin act through their downstream signaling pathways in the SAM to integrate stem cell activity and organ initiation. This review discusses how the various regulatory pathways collectively orchestrate SAM function and touches on how their manipulation can alter stem cell activity to improve crop yield.
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Affiliation(s)
- Liu Hong
- Plant Gene Expression Center, United States Department of Agriculture—Agricultural Research Service, Albany, CA 94710, USA;
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Jennifer C. Fletcher
- Plant Gene Expression Center, United States Department of Agriculture—Agricultural Research Service, Albany, CA 94710, USA;
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA 94720, USA
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Wenzl C, Lohmann JU. 3D imaging reveals apical stem cell responses to ambient temperature. Cells Dev 2023; 175:203850. [PMID: 37182581 DOI: 10.1016/j.cdev.2023.203850] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/04/2023] [Accepted: 05/09/2023] [Indexed: 05/16/2023]
Abstract
Plant growth is driven by apical meristems at the shoot and root growth points, which comprise continuously active stem cell populations. While many of the key factors involved in homeostasis of the shoot apical meristem (SAM) have been extensively studied under artificial constant growth conditions, only little is known how variations in the environment affect the underlying regulatory network. To shed light on the responses of the SAM to ambient temperature, we combined 3D live imaging of fluorescent reporter lines that allowed us to monitor the activity of two key regulators of stem cell homeostasis in the SAM namely CLAVATA3 (CLV3) and WUSCHEL (WUS), with computational image analysis to derive morphological and cellular parameters of the SAM. Whereas CLV3 expression marks the stem cell population, WUS promoter activity is confined to the organizing center (OC), the niche cells adjacent to the stem cells, hence allowing us to record on the two central cell populations of the SAM. Applying an integrated computational analysis of our data we found that variations in ambient temperature not only led to specific changes in spatial expression patterns of key regulators of SAM homeostasis, but also correlated with modifications in overall cellular organization and shoot meristem morphology.
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Affiliation(s)
- Christian Wenzl
- Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, D-69120 Heidelberg, Germany
| | - Jan U Lohmann
- Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, D-69120 Heidelberg, Germany.
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Wang Y, Jiao Y. Cell signaling in the shoot apical meristem. PLANT PHYSIOLOGY 2023; 193:70-82. [PMID: 37224874 DOI: 10.1093/plphys/kiad309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/24/2023] [Accepted: 05/10/2023] [Indexed: 05/26/2023]
Abstract
Distinct from animals, plants maintain organogenesis from specialized tissues termed meristems throughout life. In the shoot apex, the shoot apical meristem (SAM) produces all aerial organs, such as leaves, from its periphery. For this, the SAM needs to precisely balance stem cell renewal and differentiation, which is achieved through dynamic zonation of the SAM, and cell signaling within functional domains is key for SAM functions. The WUSCHEL-CLAVATA feedback loop plays a key role in SAM homeostasis, and recent studies have uncovered new components, expanding our understanding of the spatial expression and signaling mechanism. Advances in polar auxin transport and signaling have contributed to knowledge of the multifaceted roles of auxin in the SAM and organogenesis. Finally, single-cell techniques have expanded our understanding of the cellular functions within the shoot apex at single-cell resolution. In this review, we summarize the most up-to-date understanding of cell signaling in the SAM and focus on the multiple levels of regulation of SAM formation and maintenance.
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Affiliation(s)
- Ying Wang
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuling Jiao
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences in Weifang, Weifang, Shandong 261325, China
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Minow MAA, Coneva V, Lesy V, Misyura M, Colasanti J. Plant gene silencing signals move from the phloem to influence gene expression in shoot apical meristems. BMC PLANT BIOLOGY 2022; 22:606. [PMID: 36550422 PMCID: PMC9783409 DOI: 10.1186/s12870-022-03998-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND Small RNAs (sRNA) are potent regulators of gene expression that can diffuse short distances between cells and move long distances through plant vasculature. However, the degree to which sRNA silencing signals can move from the phloem to the shoot apical meristem (SAM) remains unclear. RESULTS Two independent transgenic approaches were used to examine whether phloem sRNA silencing can reach different domains of the SAM and silence SAM-expressed genes. First, the phloem companion-cell specific SUCROSE-PROTON SYMPORTER2 (SUC2) promoter was used to drive expression of an inverted repeat to target the FD gene, an exclusively SAM-localized floral regulator. Second, the SUC2 promoter was used to express an artificial microRNA (aMiR) designed to target a synthetic CLAVATA3 (CLV3) transgene in SAM stem cells. Both phloem silencing signals phenocopied the loss of function of their targets and altered target gene expression suggesting that a phloem-to-SAM silencing communication axis exists, connecting distal regions of the plant to SAM stem cells. CONCLUSIONS Demonstration of phloem-to-SAM silencing reveals a regulatory link between somatic sRNA expressed in distal regions of the plant and the growing shoot. Since the SAM stem cells ultimately produce the gametes, we discuss the intriguing possibility that phloem-to-SAM sRNA trafficking could allow transient somatic sRNA expression to manifest stable, transgenerational epigenetic changes.
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Affiliation(s)
- Mark A. A. Minow
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East Guelph, Ontario, Canada
| | - Viktoriya Coneva
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East Guelph, Ontario, Canada
| | - Victoria Lesy
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East Guelph, Ontario, Canada
| | - Max Misyura
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East Guelph, Ontario, Canada
| | - Joseph Colasanti
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East Guelph, Ontario, Canada
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Min Y, Ballerini ES, Edwards MB, Hodges SA, Kramer EM. Genetic architecture underlying variation in floral meristem termination in Aquilegia. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:6241-6254. [PMID: 35731618 PMCID: PMC9756955 DOI: 10.1093/jxb/erac277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Floral organs are produced by floral meristems (FMs), which harbor stem cells in their centers. Since each flower only has a finite number of organs, the stem cell activity of an FM will always terminate at a specific time point, a process termed floral meristem termination (FMT). Variation in the timing of FMT can give rise to floral morphological diversity, but how this process is fine-tuned at a developmental and evolutionary level is poorly understood. Flowers from the genus Aquilegia share identical floral organ arrangement except for stamen whorl number (SWN), making Aquilegia a well-suited system for investigation of this process: differences in SWN between species represent differences in the timing of FMT. By crossing A. canadensis and A. brevistyla, quantitative trait locus (QTL) mapping has revealed a complex genetic architecture with seven QTL. We explored potential candidate genes under each QTL and characterized novel expression patterns of select loci of interest using in situ hybridization. To our knowledge, this is the first attempt to dissect the genetic basis of how natural variation in the timing of FMT is regulated, and our results provide insight into how floral morphological diversity can be generated at the meristematic level.
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Affiliation(s)
| | - Evangeline S Ballerini
- Department of Biological Sciences, California State University, Sacramento, Sacramento, CA, USA
| | - Molly B Edwards
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Scott A Hodges
- Department of Ecology & Marine Biology, University of California, Santa Barbara, CA, USA
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11
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Nosaka-Takahashi M, Kato M, Kumamaru T, Sato Y. Measurements of the number of specified and unspecified cells in the shoot apical meristem during a plastochron in rice (Oryza sativa) reveal the robustness of cellular specification process in plant development. PLoS One 2022; 17:e0269374. [PMID: 35657937 PMCID: PMC9165865 DOI: 10.1371/journal.pone.0269374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 05/19/2022] [Indexed: 12/04/2022] Open
Abstract
The shoot apical meristem (SAM) is composed of a population of stem cells giving rise to the aboveground parts of plants. It maintains itself by controlling the balance of cell proliferation and specification. Although knowledge of the mechanisms maintaining the SAM has been accumulating, the processes of cellular specification to form leaves and replenishment of unspecified cells in the SAM during a plastochron (the time interval between which two successive leaf primordia are formed) is still obscure. In this study, we developed a method to quantify the number of specified and unspecified cells in the SAM and used it to elucidate the dynamics of cellular specification in the SAM during a plastochron in rice. OSH1 is a KNOX (KNOTTED1-like homeobox) gene in rice that is expressed in the unspecified cells in the SAM, but not in specified cells. Thus, we could visualize and count the nuclei of unspecified cells by fluorescent immunohistochemical staining with an anti-OSH1 antibody followed by fluorescein isothiocyanate detection. By double-staining with propidium iodide (which stains all nuclei) and then overlaying the images, we could also detect and count the specified cells. By using these measurements in combination with morphological observation, we defined four developmental stages of SAM that portray cellular specification and replenishment of unspecified cells in the SAM during a plastochron. In addition, through the analysis of mutant lines with altered size and shape of the SAM, we found that the number of specified cells destined to form a leaf primordium is not affected by mild perturbations of meristem size and shape. Our study highlights the dynamism and flexibility in stem cell maintenance in the SAM during a plastochron and the robustness of plant development.
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Affiliation(s)
- Misuzu Nosaka-Takahashi
- National Institute of Genetics, Shizuoka, Japan
- Department of Genetics, School of Life Science, Sokendai (Graduate University for Advanced Studies), Shizuoka, Japan
- * E-mail:
| | - Makio Kato
- Graduate School of Bioagricultural Sciences, Nagoya University, Aichi, Japan
| | - Toshihiro Kumamaru
- Faculty of Agriculture, Institute of Genetic Resources, Kyushu University, Fukuoka, Japan
| | - Yutaka Sato
- National Institute of Genetics, Shizuoka, Japan
- Department of Genetics, School of Life Science, Sokendai (Graduate University for Advanced Studies), Shizuoka, Japan
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12
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Müller-Xing R, Ardiansyah R, Xing Q, Faivre L, Tian J, Wang G, Zheng Y, Wang X, Jing T, de Leau E, Chen S, Chen S, Schubert D, Goodrich J. Polycomb proteins control floral determinacy by H3K27me3-mediated repression of pluripotency genes in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2385-2402. [PMID: 35045165 DOI: 10.1093/jxb/erac013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
Polycomb group (PcG) protein-mediated histone methylation (H3K27me3) controls the correct spatiotemporal expression of numerous developmental regulators in Arabidopsis. Epigenetic silencing of the stem cell factor gene WUSCHEL (WUS) in floral meristems (FMs) depends on H3K27me3 deposition by PcG proteins. However, the role of H3K27me3 in silencing of other meristematic regulator and pluripotency genes during FM determinacy has not yet been studied. To this end, we report the genome-wide dynamics of H3K27me3 levels during FM arrest and the consequences of strongly depleted PcG activity on early flower morphogenesis including enlarged and indeterminate FMs. Strong depletion of H3K27me3 levels results in misexpression of the FM identity gene AGL24, which partially causes floral reversion leading to ap1-like flowers and indeterminate FMs ectopically expressing WUS and SHOOT MERISTEMLESS (STM). Loss of STM can rescue supernumerary floral organs and FM indeterminacy in H3K27me3-deficient flowers, indicating that the hyperactivity of the FMs is at least partially a result of ectopic STM expression. Nonetheless, WUS remained essential for the FM activity. Our results demonstrate that PcG proteins promote FM determinacy at multiple levels of the floral gene regulatory network, silencing initially floral regulators such as AGL24 that promotes FM indeterminacy and, subsequently, meristematic pluripotency genes such as WUS and STM during FM arrest.
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Affiliation(s)
- Ralf Müller-Xing
- Lushan Botanical Garden, Chinese Academy of Sciences, Jiujiang, China
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration (Northeast Forestry University), Ministry of Education, Harbin, China
- Plant Epigenetics and Development, Institute of Genetics, College of Life Science, Northeast Forestry University, Harbin, China
- Institute of Molecular Plant Sciences, The University of Edinburgh, Edinburgh, UK
| | - Rhomi Ardiansyah
- Lushan Botanical Garden, Chinese Academy of Sciences, Jiujiang, China
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration (Northeast Forestry University), Ministry of Education, Harbin, China
- Plant Epigenetics and Development, Institute of Genetics, College of Life Science, Northeast Forestry University, Harbin, China
| | - Qian Xing
- Lushan Botanical Garden, Chinese Academy of Sciences, Jiujiang, China
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration (Northeast Forestry University), Ministry of Education, Harbin, China
- Plant Epigenetics and Development, Institute of Genetics, College of Life Science, Northeast Forestry University, Harbin, China
- Institute of Molecular Plant Sciences, The University of Edinburgh, Edinburgh, UK
| | - Léa Faivre
- Epigenetics of Plants, Freie Universität Berlin, Berlin, Germany
| | - Jingjing Tian
- Lushan Botanical Garden, Chinese Academy of Sciences, Jiujiang, China
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration (Northeast Forestry University), Ministry of Education, Harbin, China
- Plant Epigenetics and Development, Institute of Genetics, College of Life Science, Northeast Forestry University, Harbin, China
| | - Guohua Wang
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, China
- Information and Computer Engineering College, Northeast Forestry University, Harbin, China
| | - Yucai Zheng
- Lushan Botanical Garden, Chinese Academy of Sciences, Jiujiang, China
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration (Northeast Forestry University), Ministry of Education, Harbin, China
- Plant Epigenetics and Development, Institute of Genetics, College of Life Science, Northeast Forestry University, Harbin, China
| | - Xue Wang
- Plant Epigenetics and Development, Institute of Genetics, College of Life Science, Northeast Forestry University, Harbin, China
| | - Tingting Jing
- Lushan Botanical Garden, Chinese Academy of Sciences, Jiujiang, China
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration (Northeast Forestry University), Ministry of Education, Harbin, China
- Plant Epigenetics and Development, Institute of Genetics, College of Life Science, Northeast Forestry University, Harbin, China
| | - Erica de Leau
- Institute of Molecular Plant Sciences, The University of Edinburgh, Edinburgh, UK
| | - Song Chen
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, China
| | - Su Chen
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, China
| | - Daniel Schubert
- Epigenetics of Plants, Freie Universität Berlin, Berlin, Germany
| | - Justin Goodrich
- Institute of Molecular Plant Sciences, The University of Edinburgh, Edinburgh, UK
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13
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CLAVATA3 mediated simultaneous control of transcriptional and post-translational processes provides robustness to the WUSCHEL gradient. Nat Commun 2021; 12:6361. [PMID: 34737298 PMCID: PMC8569176 DOI: 10.1038/s41467-021-26586-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 10/12/2021] [Indexed: 11/08/2022] Open
Abstract
Regulation of the homeodomain transcription factor WUSCHEL concentration is critical for stem cell homeostasis in Arabidopsis shoot apical meristems. WUSCHEL regulates the transcription of CLAVATA3 through a concentration-dependent activation-repression switch. CLAVATA3, a secreted peptide, activates receptor kinase signaling to repress WUSCHEL transcription. Considering the revised regulation, CLAVATA3 mediated repression of WUSCHEL transcription alone will lead to an unstable system. Here we show that CLAVATA3 signaling regulates nuclear-cytoplasmic partitioning of WUSCHEL to control nuclear levels and its diffusion into adjacent cells. Our work also reveals that WUSCHEL directly interacts with EXPORTINS via EAR-like domain which is also required for destabilizing WUSCHEL in the cytoplasm. We develop a combined experimental and computational modeling approach that integrates CLAVATA3-mediated transcriptional repression of WUSCHEL and post-translational control of nuclear levels with the WUSCHEL concentration-dependent regulation of CLAVATA3. We show that the dual control by the same signal forms a seamless connection between de novo WUSCHEL synthesis and sub-cellular partitioning in providing robustness to the WUSCHEL gradient.
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14
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Schlegel J, Denay G, Wink R, Pinto KG, Stahl Y, Schmid J, Blümke P, Simon RGW. Control of Arabidopsis shoot stem cell homeostasis by two antagonistic CLE peptide signalling pathways. eLife 2021; 10:e70934. [PMID: 34643181 PMCID: PMC8594942 DOI: 10.7554/elife.70934] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/30/2021] [Indexed: 11/28/2022] Open
Abstract
Stem cell homeostasis in plant shoot meristems requires tight coordination between stem cell proliferation and cell differentiation. In Arabidopsis, stem cells express the secreted dodecapeptide CLAVATA3 (CLV3), which signals through the leucine-rich repeat (LRR)-receptor kinase CLAVATA1 (CLV1) and related CLV1-family members to downregulate expression of the homeodomain transcription factor WUSCHEL (WUS). WUS protein moves from cells below the stem cell domain to the meristem tip and promotes stem cell identity, together with CLV3 expression, generating a negative feedback loop. How stem cell activity in the meristem centre is coordinated with organ initiation and cell differentiation at the periphery is unknown. We show here that the CLE40 gene, encoding a secreted peptide closely related to CLV3, is expressed in the SAM in differentiating cells in a pattern complementary to that of CLV3. CLE40 promotes WUS expression via BAM1, a CLV1-family receptor, and CLE40 expression is in turn repressed in a WUS-dependent manner. Together, CLE40-BAM1-WUS establish a second negative feedback loop. We propose that stem cell homeostasis is achieved through two intertwined pathways that adjust WUS activity and incorporate information on the size of the stem cell domain, via CLV3-CLV1, and on cell differentiation via CLE40-BAM1.
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Affiliation(s)
- Jenia Schlegel
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorfGermany
| | - Gregoire Denay
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorfGermany
| | - Rene Wink
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorfGermany
| | - Karine Gustavo Pinto
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorfGermany
| | - Yvonne Stahl
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorfGermany
| | - Julia Schmid
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorfGermany
| | - Patrick Blümke
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorfGermany
| | - Rüdiger GW Simon
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorfGermany
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15
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Leonardo B, Emanuela T, Letizia MM, Antonella M, Marco M, Fabrizio A, Beatrice BM, Adriana C. Cadmium affects cell niches maintenance in Arabidopsis thaliana post-embryonic shoot and root apical meristem by altering the expression of WUS/WOX homolog genes and cytokinin accumulation. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 167:785-794. [PMID: 34530323 DOI: 10.1016/j.plaphy.2021.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/08/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
Cadmium (Cd) is one of the most widespread polluting heavy metals in both terrestrial and aquatic environments and represents an extremely significant pollutant causing severe environmental and social problems due to its high toxicity and large solubility in water. In plants, the root is the first organ that get in contact with Cd. It is absorbed by the root system and translocated to the shoot and leaves through xylem loading, causing a variety of genetic, biochemical, and physiological damages. Cd inhibits both the root and shoot growth, but the mechanisms underlying this inhibition remain elusive. In this context in the present work we focused the attention on the effects of Cd on meristem size and organization of both shoot and root. To this aim morpho-histological and molecular analyses were carried out on 5 days old seedlings exposed or not to Cd (100 μM and 150 μM for 24) of wild type and transgenic lines expressing molecular markers with an important role in shoot and root pattern organization. More precisely, we monitored the expression pattern of WUS/CLV3 and WOX5 transcription factors involved in the establishment and maintenance of stem cell niche and the control of meristem size and of TCSn::GFP cytokinin-sensitive sensor as relevant components of hormone circuit controlling shoot and root growth. The results highlighted that the treatments with Cd impacts shoot and root size and shape by altering the paralogous WOX genes expression via cytokinin accumulation.
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Affiliation(s)
- Bruno Leonardo
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy.
| | - Talarico Emanuela
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy
| | - Madeo Maria Letizia
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy
| | - Muto Antonella
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy
| | - Minervino Marco
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy
| | - Araniti Fabrizio
- Dipartimento di Scienze Agrarie e Ambientali - Produzione, Territorio, Agroenergia, Università Statale di Milano, Via Celoria n°2, 20133, Milano, Italy
| | - Bitonti Maria Beatrice
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy
| | - Chiappetta Adriana
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy
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16
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Robust control of floral meristem determinacy by position-specific multifunctions of KNUCKLES. Proc Natl Acad Sci U S A 2021; 118:2102826118. [PMID: 34462349 DOI: 10.1073/pnas.2102826118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Floral organs are properly developed on the basis of timed floral meristem (FM) termination in Arabidopsis In this process, two known regulatory pathways are involved. The WUSCHEL (WUS)-CLAVATA3 (CLV3) feedback loop is vital for the spatial establishment and maintenance of the FM, while AGAMOUS (AG)-WUS transcriptional cascades temporally repress FM. At stage 6 of flower development, a C2H2-type zinc finger repressor that is a target of AG, KNUCKLES (KNU), directly represses the stem cell identity gene WUS in the organizing center for FM termination. However, how the robust FM activity is fully quenched within a limited time frame to secure carpel development is not fully understood. Here, we demonstrate that KNU directly binds to the CLV1 locus and the cis-regulatory element on CLV3 promoter and represses their expression during FM determinacy control. Furthermore, KNU physically interacts with WUS, and this interaction inhibits WUS from sustaining CLV3 in the central zone. The KNU-WUS interaction also interrupts the formation of WUS homodimers and WUS-HAIRYMERISTEM 1 heterodimers, both of which are required for FM maintenance. Overall, our findings describe a regulatory framework in which KNU plays a position-specific multifunctional role for the tightly controlled FM determinacy.
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17
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Hirakawa Y. CLAVATA3, a plant peptide controlling stem cell fate in the meristem. Peptides 2021; 142:170579. [PMID: 34033873 DOI: 10.1016/j.peptides.2021.170579] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 10/21/2022]
Abstract
CLAVATA3 (CLV3) is a peptide signal initially identified in the analysis of clv mutants in the model plant Arabidopsis thaliana, as a regulator of meristem homeostasis and floral organ numbers. CLV3 homologs are widely conserved in land plants, collectively called CLV3/ESR-related (CLE) genes. A 12-amino acid CLE peptide with hydroxyproline residues was identified in Zinnia elegans cell culture system, in which cells secrete a CLE peptide called tracheary element differentiation factor (TDIF) into the culture medium. Mature CLV3 peptide is also a post-translationally modified short peptide containing additional triarabinosylation on a hydroxyproline residue. Genetic studies have revealed the involvement of leucin-rich repeat receptor-like kinases (LRR-RLKs) in CLV3 signaling, including CLV1/BAM-CIK, CLV2-CRN and RPK2, although the mechanisms of signal transduction and integration via crosstalk is still largely unknown. Recent studies on bryophyte model species provided a clue to understand evolution and ancestral function of CLV signaling in land plants. Fundamental understanding on CLV signaling provided an opportunity to optimize the crop yield traits using a novel breeding technology with CRISPR/Cas genome editing.
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Affiliation(s)
- Yuki Hirakawa
- Department of Life Science, Faculty of Science, Gakushuin University, Tokyo, Japan.
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18
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Kitazawa MS. Developmental stochasticity and variation in floral phyllotaxis. JOURNAL OF PLANT RESEARCH 2021; 134:403-416. [PMID: 33821352 PMCID: PMC8106590 DOI: 10.1007/s10265-021-01283-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
Floral phyllotaxis is a relatively robust phenotype; trimerous and pentamerous arrangements are widely observed in monocots and core eudicots. Conversely, it also shows variability in some angiosperm clades such as 'ANA' grade (Amborellales, Nymphaeales, and Austrobaileyales), magnoliids, and Ranunculales. Regardless of the phylogenetic relationship, however, phyllotactic pattern formation appears to be a common process. What are the causes of the variability in floral phyllotaxis and how has the variation of floral phyllotaxis contributed to floral diversity? In this review, I summarize recent progress in studies on two related fields to develop answers to these questions. First, it is known that molecular and cellular stochasticity are inevitably found in biological systems, including plant development. Organisms deal with molecular stochasticity in several ways, such as dampening noise through gene networks or maintaining function through cellular redundancy. Recent studies on molecular and cellular stochasticity suggest that stochasticity is not always detrimental to plants and that it is also essential in development. Second, studies on vegetative and inflorescence phyllotaxis have shown that plants often exhibit variability and flexibility in phenotypes. Three types of phyllotaxis variations are observed, namely, fluctuation around the mean, transition between regular patterns, and a transient irregular organ arrangement called permutation. Computer models have demonstrated that stochasticity in the phyllotactic pattern formation plays a role in pattern transitions and irregularities. Variations are also found in the number and positioning of floral organs, although it is not known whether such variations provide any functional advantages. Two ways of diversification may be involved in angiosperm floral evolution: precise regulation of organ position and identity that leads to further specialization of organs and organ redundancy that leads to flexibility in floral phyllotaxis.
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Affiliation(s)
- Miho S Kitazawa
- Center for Education in Liberal Arts and Sciences, Osaka University, 1-16 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan.
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19
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Zhang L, DeGennaro D, Lin G, Chai J, Shpak ED. ERECTA family signaling constrains CLAVATA3 and WUSCHEL to the center of the shoot apical meristem. Development 2021; 148:dev.189753. [PMID: 33593817 DOI: 10.1242/dev.189753] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 02/08/2021] [Indexed: 12/12/2022]
Abstract
The shoot apical meristem (SAM) is a reservoir of stem cells that gives rise to all post-embryonic above-ground plant organs. The size of the SAM remains stable over time owing to a precise balance of stem cell replenishment versus cell incorporation into organ primordia. The WUSCHEL (WUS)/CLAVATA (CLV) negative feedback loop is central to SAM size regulation. Its correct function depends on accurate spatial expression of WUS and CLV3 A signaling pathway, consisting of ERECTA family (ERf) receptors and EPIDERMAL PATTERNING FACTOR LIKE (EPFL) ligands, restricts SAM width and promotes leaf initiation. Although ERf receptors are expressed throughout the SAM, EPFL ligands are expressed in its periphery. Our genetic analysis of Arabidopsis demonstrated that ERfs and CLV3 synergistically regulate the size of the SAM, and wus is epistatic to ERf genes. Furthermore, activation of ERf signaling with exogenous EPFLs resulted in a rapid decrease of CLV3 and WUS expression. ERf-EPFL signaling inhibits expression of WUS and CLV3 in the periphery of the SAM, confining them to the center. These findings establish the molecular mechanism for stem cell positioning along the radial axis.
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Affiliation(s)
- Liang Zhang
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Daniel DeGennaro
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Guangzhong Lin
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jijie Chai
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China.,Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany.,Institute of Biochemistry, University of Cologne, Zuelpicher Strasse 47, 50674 Cologne, Germany
| | - Elena D Shpak
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
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20
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Lopes FL, Galvan-Ampudia C, Landrein B. WUSCHEL in the shoot apical meristem: old player, new tricks. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:1527-1535. [PMID: 33332559 DOI: 10.1093/jxb/eraa572] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 12/01/2020] [Indexed: 05/21/2023]
Abstract
The maintenance of the stem cell niche in the shoot apical meristem, the structure that generates all of the aerial organs of the plant, relies on a canonical feedback loop between WUSCHEL (WUS) and CLAVATA3 (CLV3). WUS is a homeodomain transcription factor expressed in the organizing centre that moves to the central zone to promote stem cell fate. CLV3 is a peptide whose expression is induced by WUS in the central zone and that can move back to the organizing centre to inhibit WUS expression. Within the past 20 years since the initial formulation of the CLV-WUS feedback loop, the mechanisms of stem cell maintenance have been intensively studied and the function of WUS has been redefined. In this review, we highlight the most recent advances in our comprehension of the molecular mechanisms of WUS function, of its interaction with other transcription factors and hormonal signals, and of its connection to environmental signals. Through this, we will show how WUS can integrate both internal and external cues to adapt meristem function to the plant environment.
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Affiliation(s)
- Filipa Lara Lopes
- Plant Stress Signaling, Instituto Gulbenkian de Ciência, Rua da Quinta Grande, Oeiras, Portugal
| | - Carlos Galvan-Ampudia
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS, INRAE, Lyon Cedex, France
| | - Benoit Landrein
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS, INRAE, Lyon Cedex, France
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21
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Liu Z, Shpak ED, Hong T. A mathematical model for understanding synergistic regulations and paradoxical feedbacks in the shoot apical meristem. Comput Struct Biotechnol J 2020; 18:3877-3889. [PMID: 33335685 PMCID: PMC7720093 DOI: 10.1016/j.csbj.2020.11.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 01/22/2023] Open
Abstract
The shoot apical meristem (SAM) is the primary stem cell niche in plant shoots. Stem cells in the SAM are controlled by an intricate regulatory network, including negative feedback between WUSCHEL (WUS) and CLAVATA3 (CLV3). Recently, we identified a group of signals, Epidermal Patterning Factor-Like (EPFL) proteins, that are produced at the peripheral region and are important for SAM homeostasis. Here, we present a mathematical model for the SAM regulatory network. The model revealed that the SAM uses EPFL and signals such as HAIRY MERISTEM from the middle in a synergistic manner to constrain both WUS and CLV3. We found that interconnected negative and positive feedbacks between WUS and CLV3 ensure stable WUS expression in the SAM when facing perturbations, and the positive feedback loop also maintains distinct cell populations containing WUS on and CLV3 on cells in the apical-basal direction. Furthermore, systematic perturbations of the parameters revealed a tradeoff between optimizations of multiple patterning features. Our results provide a holistic view of the regulation of SAM patterning in multiple dimensions. They give insights into how Arabidopsis integrates signals from lateral and apical-basal axes to control the SAM patterning, and they shed light into design principles that may be widely useful for understanding regulatory networks of stem cell niche.
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Affiliation(s)
- Ziyi Liu
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN, United States
| | - Elena D. Shpak
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, United States
| | - Tian Hong
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, United States
- National Institute for Mathematical and Biological Synthesis, Knoxville, TN, United States
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22
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Klawe FZ, Stiehl T, Bastian P, Gaillochet C, Lohmann JU, Marciniak-Czochra A. Mathematical modeling of plant cell fate transitions controlled by hormonal signals. PLoS Comput Biol 2020; 16:e1007523. [PMID: 32687508 PMCID: PMC7392350 DOI: 10.1371/journal.pcbi.1007523] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 07/30/2020] [Accepted: 06/12/2020] [Indexed: 02/08/2023] Open
Abstract
Coordination of fate transition and cell division is crucial to maintain the plant architecture and to achieve efficient production of plant organs. In this paper, we analysed the stem cell dynamics at the shoot apical meristem (SAM) that is one of the plant stem cells locations. We designed a mathematical model to elucidate the impact of hormonal signaling on the fate transition rates between different zones corresponding to slowly dividing stem cells and fast dividing transit amplifying cells. The model is based on a simplified two-dimensional disc geometry of the SAM and accounts for a continuous displacement towards the periphery of cells produced in the central zone. Coupling growth and hormonal signaling results in a nonlinear system of reaction-diffusion equations on a growing domain with the growth rate depending on the model components. The model is tested by simulating perturbations in the level of key transcription factors that maintain SAM homeostasis. The model provides new insights on how the transcription factor HECATE is integrated in the regulatory network that governs stem cell differentiation.
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Affiliation(s)
- Filip Z. Klawe
- Institute of Applied Mathematics, Heidelberg University, Heidelberg, Germany
| | - Thomas Stiehl
- Institute of Applied Mathematics, Heidelberg University, Heidelberg, Germany
- Interdisciplinary Center for Scientific Computing, Heidelberg University, Heidelberg, Germany
- Bioquant Center, Heidelberg University, Heidelberg, Germany
| | - Peter Bastian
- Interdisciplinary Center for Scientific Computing, Heidelberg University, Heidelberg, Germany
| | | | - Jan U. Lohmann
- Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Anna Marciniak-Czochra
- Institute of Applied Mathematics, Heidelberg University, Heidelberg, Germany
- Interdisciplinary Center for Scientific Computing, Heidelberg University, Heidelberg, Germany
- Bioquant Center, Heidelberg University, Heidelberg, Germany
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23
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Fuchs M, Lohmann JU. Aiming for the top: non-cell autonomous control of shoot stem cells in Arabidopsis. JOURNAL OF PLANT RESEARCH 2020; 133:297-309. [PMID: 32146616 PMCID: PMC7214502 DOI: 10.1007/s10265-020-01174-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 02/27/2020] [Indexed: 05/13/2023]
Abstract
In multicellular organisms, not all cells are created equal. Instead, organismal complexity is achieved by specialisation and division of labour between distinct cell types. Therefore, the organism depends on the presence, correct proportion and function of all cell types. It follows that early development is geared towards setting up the basic body plan and to specify cell lineages. Since plants employ a post-embryonic mode of development, the continuous growth and addition of new organs require a source of new cells, as well as a strict regulation of cellular composition throughout the entire life-cycle. To meet these demands, evolution has brought about complex regulatory systems to maintain and control continuously active stem cell systems. Here, we review recent work on the mechanisms of non cell-autonomous control of shoot stem cells in the model plant Arabidopsis thaliana with a strong focus on the cell-to-cell mobility and function of the WUSCHEL homeodomain transcription factor.
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Affiliation(s)
- Michael Fuchs
- Department of Stem Cell Biology, Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120, Heidelberg, Germany
| | - Jan U Lohmann
- Department of Stem Cell Biology, Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120, Heidelberg, Germany.
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24
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Che G, Gu R, Zhao J, Liu X, Song X, Zi H, Cheng Z, Shen J, Wang Z, Liu R, Yan L, Weng Y, Zhang X. Gene regulatory network controlling carpel number variation in cucumber. Development 2020; 147:dev.184788. [PMID: 32165491 DOI: 10.1242/dev.184788] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 02/26/2020] [Indexed: 01/09/2023]
Abstract
The WUSCHEL-CLAVATA3 pathway genes play an essential role in shoot apical meristem maintenance and floral organ development, and under intense selection during crop domestication. The carpel number is an important fruit trait that affects fruit shape, size and internal quality in cucumber, but the molecular mechanism remains elusive. Here, we found that CsCLV3 expression was negatively correlated with carpel number in cucumber cultivars. CsCLV3-RNAi led to increased number of petals and carpels, whereas overexpression of CsWUS resulted in more sepals, petals and carpels, suggesting that CsCLV3 and CsWUS function as a negative and a positive regulator for carpel number variation, respectively. Biochemical analyses indicated that CsWUS directly bound to the promoter of CsCLV3 and activated its expression. Overexpression of CsFUL1A , a FRUITFULL-like MADS-box gene, resulted in more petals and carpels. CsFUL1A can directly bind to the CsWUS promoter to stimulate its expression. Furthermore, we found that auxin participated in carpel number variation in cucumber through interaction of CsARF14 with CsWUS. Therefore, we have identified a gene regulatory pathway involving CsCLV3, CsWUS, CsFUL1A and CsARF14 in determining carpel number variation in an important vegetable crop - cucumber.
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Affiliation(s)
- Gen Che
- State Key Laboratories of Agrobiotechnology, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Ran Gu
- State Key Laboratories of Agrobiotechnology, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Jianyu Zhao
- State Key Laboratories of Agrobiotechnology, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Xiaofeng Liu
- State Key Laboratories of Agrobiotechnology, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Xiaofei Song
- Analysis and Testing Centre, Hebei Normal University of Science and Technology, Qinhuangdao 066004, China
| | - Hailing Zi
- Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
| | - Zhihua Cheng
- State Key Laboratories of Agrobiotechnology, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Junjun Shen
- State Key Laboratories of Agrobiotechnology, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Zhongyi Wang
- State Key Laboratories of Agrobiotechnology, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Renyi Liu
- Center for Agroforestry Mega Data Science and FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Liying Yan
- College of Horticulture Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao 066004, China
| | - Yiqun Weng
- USDA-ARS, Vegetable Crops Research Unit, Horticulture Department, University of Wisconsin-Madison, 1575 Linden Drive, Madison, WI 53706, USA
| | - Xiaolan Zhang
- State Key Laboratories of Agrobiotechnology, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
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25
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Han H, Liu X, Zhou Y. Transcriptional circuits in control of shoot stem cell homeostasis. CURRENT OPINION IN PLANT BIOLOGY 2020; 53:50-56. [PMID: 31766002 DOI: 10.1016/j.pbi.2019.10.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 10/16/2019] [Accepted: 10/17/2019] [Indexed: 05/02/2023]
Abstract
Plant shoot apical meristems (SAMs) play essential roles in plant growth and development. Located at the growing tip of a plant stem, these dome-like structures contain stem cells, which serve to perpetuate themselves in an undifferentiated state while continually adding new cells that differentiate and eventually form all above-ground tissues. In a SAM, the pool of stem cells is dynamically maintained through a balance between cell division (self-renewal) and differentiation (loss of stem-cell identity). In the model plant Arabidopsis thaliana, a negative feedback loop between WUSCHEL (WUS) and the CLAVATA3 (CLV3) plays important roles in maintaining the stem cell population. In this review, we highlight recent findings mainly from studies in Arabidopsis, and summarize the research progress on understanding how multiple transcriptional circuits integrate and function at different cell layers to control the WUS-CLV3 loop and stem cell homeostasis.
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Affiliation(s)
- Han Han
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, United States; Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, United States
| | - Xing Liu
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, United States; Department of Biochemistry, Purdue University, West Lafayette, IN 47907, United States
| | - Yun Zhou
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, United States; Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, United States.
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26
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Li S, Zhu Y, Varshney RK, Zhan J, Zheng X, Shi J, Wang X, Liu G, Wang H. A systematic dissection of the mechanisms underlying the natural variation of silique number in rapeseed (Brassica napus L.) germplasm. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:568-580. [PMID: 31368615 PMCID: PMC6953207 DOI: 10.1111/pbi.13224] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 07/02/2019] [Accepted: 07/17/2019] [Indexed: 05/12/2023]
Abstract
Silique number is the most important component of yield in rapeseed (Brassica napus L.). To dissect the mechanism underlying the natural variation of silique number in rapeseed germplasm, a series of studies were performed. A panel of 331 core lines was employed to genome-wide association study (GWAS), and 27 loci (including 20 novel loci) were identified. The silique number difference between the more- and fewer-silique lines can be attributed to the accumulative differences in flower number and silique setting rate. Each of them accounted for 75.2% and 24.8%, respectively. The silique number was highly associated with the total photosynthesis and biomass. Microscopic analysis showed that the difference between extremely more- and fewer-silique lines normally occurred at the amount of flower bud but not morphology. Transcriptome analysis of shoot apical meristem (SAM) suggested that most of enriched groups were associated with the auxin biosynthesis/metabolism, vegetative growth and nutrition/energy accumulation. By integrating GWAS and RNA-seq results, six promising candidate genes were identified, and some of them were related to biomass accumulation. In conclusion, the natural variation of silique number is largely affected by the biomass and nutrition accumulation, which essentially reflects the positive regulatory relationship between the source and sink. Our study provides a comprehensive and systematic explanation for natural variation of silique number in rapeseed, which provides a foundation for its improvement.
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Affiliation(s)
- Shuyu Li
- Oil Crops Research Institute of the Chinese Academy of Agricultural SciencesKey Laboratory of Biology and Genetic Improvement of Oil CropsMinistry of AgricultureWuhanChina
- Crop Research InstituteJiangxi Academy of Agricultural SciencesNanchangChina
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanChina
| | - Yaoyao Zhu
- Oil Crops Research Institute of the Chinese Academy of Agricultural SciencesKey Laboratory of Biology and Genetic Improvement of Oil CropsMinistry of AgricultureWuhanChina
| | - Rajeev Kumar Varshney
- Center of Excellence in Genomics & Systems BiologyInternational Crops Research Institute for the Semi‐Arid Tropics (ICRISAT)PatancheruIndia
| | - Jiepeng Zhan
- Oil Crops Research Institute of the Chinese Academy of Agricultural SciencesKey Laboratory of Biology and Genetic Improvement of Oil CropsMinistry of AgricultureWuhanChina
| | - Xiaoxiao Zheng
- Oil Crops Research Institute of the Chinese Academy of Agricultural SciencesKey Laboratory of Biology and Genetic Improvement of Oil CropsMinistry of AgricultureWuhanChina
| | - Jiaqin Shi
- Oil Crops Research Institute of the Chinese Academy of Agricultural SciencesKey Laboratory of Biology and Genetic Improvement of Oil CropsMinistry of AgricultureWuhanChina
| | - Xinfa Wang
- Oil Crops Research Institute of the Chinese Academy of Agricultural SciencesKey Laboratory of Biology and Genetic Improvement of Oil CropsMinistry of AgricultureWuhanChina
| | - Guihua Liu
- Oil Crops Research Institute of the Chinese Academy of Agricultural SciencesKey Laboratory of Biology and Genetic Improvement of Oil CropsMinistry of AgricultureWuhanChina
| | - Hanzhong Wang
- Oil Crops Research Institute of the Chinese Academy of Agricultural SciencesKey Laboratory of Biology and Genetic Improvement of Oil CropsMinistry of AgricultureWuhanChina
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27
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Shimotohno A, Scheres B. Topology of regulatory networks that guide plant meristem activity: similarities and differences. CURRENT OPINION IN PLANT BIOLOGY 2019; 51:74-80. [PMID: 31102928 DOI: 10.1016/j.pbi.2019.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/07/2019] [Accepted: 04/12/2019] [Indexed: 06/09/2023]
Abstract
Plants adapt their morphology in response to variable environmental conditions such as nitrate availability, drought, and temperature shifts. Three crucial aspects to this developmental plasticity are the control of initiation, identity and activity of meristems. At the cellular level, the activity of meristems is controlled by balancing self-renewal in stem cells, amplifying divisions in their daughter cells, and cell differentiation. Recent studies in plants have uncovered transcription factors regulating meristem activity at cellular resolution, and regulatory networks that couple these factors with phytohormone signalling for global plant growth regulation. Here, we highlight selected recent advances in our understanding of the multidimensional transcriptional networks that regulate meristem activity and discuss emerging insights on how a selection of environmental cues impinges on these networks.
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Affiliation(s)
- Akie Shimotohno
- Department of Biological Science, The University of Tokyo, Tokyo 113-0033, Japan.
| | - Ben Scheres
- Department of Plant Sciences, Wageningen University and Research, Wageningen 6708PB, The Netherlands; Rijk Zwaan Research and Development, Fijnaart 4793 RS, The Netherlands.
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28
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Zhao W, Chao H, Zhang L, Ta N, Zhao Y, Li B, Zhang K, Guan Z, Hou D, Chen K, Li H, Zhang L, Wang H, Li M. Integration of QTL Mapping and Gene Fishing Techniques to Dissect the Multi-Main Stem Trait in Rapeseed ( Brassica napus L.). FRONTIERS IN PLANT SCIENCE 2019; 10:1152. [PMID: 31616451 PMCID: PMC6764107 DOI: 10.3389/fpls.2019.01152] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 08/23/2019] [Indexed: 05/31/2023]
Abstract
Rapeseed is one of the most important oilseed crops in the world. Improving the production of rapeseed is beneficial to relieve the shortage of edible vegetable oil. As the organ of support and transport, the main stem of rapeseed controls the plant architecture, transports the water and nutrients, and determines the number of inflorescence. Increasing the number of main stems would be helpful for the yield improvement in Brassica napus (B. napus). This attractive multi-main stem (MMS) trait was observed in the KN DH population. We investigated not only the frequency of MMS traits but also dissected the genetic basis with QTL mapping analysis and Gene-Fishing technique. A total of 43 QTLs were identified for MMS based on high-density linkage map, which explained 2.95-14.9% of the phenotypic variation, among which two environmental stable QTLs (cqMMS.A3-2 and cqMMS.C3-5) were identified in winter and semi-winter environments. Epistatic interaction analysis indicated cqMMS.C3-5 was an important loci for MMS. According to the functional annotation, 159 candidate genes within QTL confidence intervals, corresponding to 148 Arabidopsis thaliana (A. thaliana) homologous genes, were identified, which regulated lateral bud development and tiller of stem, such as shoot meristemless (STM), WUSCHEL-regulated-related genes, cytokinin response factors (CRF5), cytokinin oxidase (CKX4), gibberellin-regulated (RDK1), auxin-regulated gene (ARL, IAR4), and auxin-mediated signaling gene (STV1). Based on Gene-Fishing analysis between the natural plants and the double-main stem (DMS) plant, 31 differentially expressed genes (DEGs) were also obtained, which were related to differentiation and formation of lateral buds, biotic stimulus, defense response, drought and salt-stress responses, as well as cold-response functional genes. In addition, by combining the candidate genes in QTL regions with the DEGs that were obtained by Gene-Fishing technique, six common candidate genes (RPT2A, HLR, CRK, LRR-RLK, AGL79, and TCTP) were identified, which might probably be related to the formation of MMS phenotype. The present results not only would give a new insight into the genetic basis underlying the regulation of MMS but also would provide clues for plant architecture breeding in rapeseed.
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Affiliation(s)
- Weiguo Zhao
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
- Hybrid Rape Research Center of Shaanxi Province, Shaanxi Rapeseed Branch of National Centre for Oil Crops Genetic Improvement, Yangling, China
| | - Hongbo Chao
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Lina Zhang
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Na Ta
- Hybrid Rape Research Center of Shaanxi Province, Shaanxi Rapeseed Branch of National Centre for Oil Crops Genetic Improvement, Yangling, China
| | - Yajun Zhao
- Hybrid Rape Research Center of Shaanxi Province, Shaanxi Rapeseed Branch of National Centre for Oil Crops Genetic Improvement, Yangling, China
| | - Baojun Li
- Hybrid Rape Research Center of Shaanxi Province, Shaanxi Rapeseed Branch of National Centre for Oil Crops Genetic Improvement, Yangling, China
| | - Kai Zhang
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Zhoubo Guan
- Hybrid Rape Research Center of Shaanxi Province, Shaanxi Rapeseed Branch of National Centre for Oil Crops Genetic Improvement, Yangling, China
| | - Dalin Hou
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Kang Chen
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Huaixin Li
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Libin Zhang
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Hao Wang
- Hybrid Rape Research Center of Shaanxi Province, Shaanxi Rapeseed Branch of National Centre for Oil Crops Genetic Improvement, Yangling, China
| | - Maoteng Li
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
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29
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Sun B, Zhou Y, Cai J, Shang E, Yamaguchi N, Xiao J, Looi LS, Wee WY, Gao X, Wagner D, Ito T. Integration of Transcriptional Repression and Polycomb-Mediated Silencing of WUSCHEL in Floral Meristems. THE PLANT CELL 2019; 31:1488-1505. [PMID: 31068455 PMCID: PMC6635863 DOI: 10.1105/tpc.18.00450] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 03/19/2019] [Accepted: 05/01/2019] [Indexed: 05/21/2023]
Abstract
Arabidopsis (Arabidopsis thaliana) floral meristems terminate after the carpel primordia arise. This is achieved through the temporal repression of WUSCHEL (WUS), which is essential for stem cell maintenance. At floral stage 6, WUS is repressed by KNUCKLES (KNU), a repressor directly activated by AGAMOUS. KNU was suggested to repress WUS through histone deacetylation; however, how the changes in the chromatin state of WUS are initiated and maintained to terminate the floral meristem remains elusive. Here, we show that KNU integrates initial transcriptional repression with polycomb-mediated stable silencing of WUS After KNU is induced, it binds to the WUS promoter and causes eviction of SPLAYED, which is a known activator of WUS and can oppose polycomb repression. KNU also physically interacts with FERTILIZATION-INDEPENDENT ENDOSPERM, a key polycomb repressive complex2 component, and mediates the subsequent deposition of the repressive histone H3 lysine 27 trimethylation for stable silencing of WUS This multi-step silencing of WUS leads to the termination of floral stem cells, ensuring proper carpel development. Thus, our work describes a detailed mechanism for heritable floral stem cell termination in a precise spatiotemporal manner.
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Affiliation(s)
- Bo Sun
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Yingying Zhou
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Jie Cai
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Erlei Shang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Nobutoshi Yamaguchi
- Biological Science, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, 630-0192, Japan
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, 4-1-8, Honcho, Kawaguchi-shi, Saitama, 332-0012, Japan
| | - Jun Xiao
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6084
| | - Liang-Sheng Looi
- Biological Science, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, 630-0192, Japan
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, 117604, Singapore
| | - Wan-Yi Wee
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, 117604, Singapore
| | - Xiuying Gao
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Doris Wagner
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6084
| | - Toshiro Ito
- Biological Science, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, 630-0192, Japan
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, 117604, Singapore
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30
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Abstract
A fascinating feature of plant growth and development is that plants initiate organs continually throughout their lifespan. The ability to do this relies on specialized groups of pluripotent stem cells termed meristems, which allow for the elaboration of the shoot, root, and vascular systems. We now have a deep understanding of the genetic networks that control meristem initiation and stem cell maintenance, including the roles of receptors and their ligands, transcription factors, and integrated hormonal and chromatin control. This review describes these networks and discusses how this knowledge is being applied to improve crop productivity by increasing fruit size and seed number.
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Affiliation(s)
- Munenori Kitagawa
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA;
| | - David Jackson
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA;
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31
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Rodriguez-Leal D, Xu C, Kwon CT, Soyars C, Demesa-Arevalo E, Man J, Liu L, Lemmon ZH, Jones DS, Van Eck J, Jackson DP, Bartlett ME, Nimchuk ZL, Lippman ZB. Evolution of buffering in a genetic circuit controlling plant stem cell proliferation. Nat Genet 2019; 51:786-792. [PMID: 30988512 DOI: 10.1038/s41588-019-0389-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 03/07/2019] [Indexed: 01/19/2023]
Abstract
Precise control of plant stem cell proliferation is necessary for the continuous and reproducible development of plant organs1,2. The peptide ligand CLAVATA3 (CLV3) and its receptor protein kinase CLAVATA1 (CLV1) maintain stem cell homeostasis within a deeply conserved negative feedback circuit1,2. In Arabidopsis, CLV1 paralogs also contribute to homeostasis, by compensating for the loss of CLV1 through transcriptional upregulation3. Here, we show that compensation4,5 operates in diverse lineages for both ligands and receptors, but while the core CLV signaling module is conserved, compensation mechanisms have diversified. Transcriptional compensation between ligand paralogs operates in tomato, facilitated by an ancient gene duplication that impacted the domestication of fruit size. In contrast, we found little evidence for transcriptional compensation between ligands in Arabidopsis and maize, and receptor compensation differs between tomato and Arabidopsis. Our findings show that compensation among ligand and receptor paralogs is critical for stem cell homeostasis, but that diverse genetic mechanisms buffer conserved developmental programs.
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Affiliation(s)
- Daniel Rodriguez-Leal
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.,Inari Agriculture, Cambridge, MA, USA
| | - Cao Xu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.,State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Choon-Tak Kwon
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Cara Soyars
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - Jarrett Man
- Biology Department, University of Massachusetts Amherst, Amherst, MA, USA
| | - Lei Liu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Zachary H Lemmon
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.,Inari Agriculture, Cambridge, MA, USA
| | - Daniel S Jones
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Joyce Van Eck
- Boyce Thompson Institute for Plant Science, Ithaca, NY, USA.,Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | | | | | - Zachary L Nimchuk
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Zachary B Lippman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA. .,Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
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32
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McKim SM. How plants grow up. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2019; 61:257-277. [PMID: 30697935 DOI: 10.1111/jipb.12786] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 01/21/2019] [Indexed: 05/27/2023]
Abstract
A plant's lateral structures, such as leaves, branches and flowers, literally hinge on the shoot axis, making its integrity and growth fundamental to plant form. In all plants, subapical proliferation within the shoot tip displaces cells downward to extrude the cylindrical stem. Following the transition to flowering, many plants show extensive axial elongation associated with increased subapical proliferation and expansion. However, the cereal grasses also elongate their stems, called culms, due to activity within detached intercalary meristems which displaces cells upward, elevating the grain-bearing inflorescence. Variation in culm length within species is especially relevant to cereal crops, as demonstrated by the high-yielding semi-dwarfed cereals of the Green Revolution. Although previously understudied, recent renewed interest the regulation of subapical and intercalary growth suggests that control of cell division planes, boundary formation and temporal dynamics of differentiation, are likely critical mechanisms coordinating axial growth and development in plants.
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Affiliation(s)
- Sarah M McKim
- Division of Plant Sciences, University of Dundee at The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
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33
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Site-specific manipulation of Arabidopsis loci using CRISPR-Cas9 SunTag systems. Nat Commun 2019; 10:729. [PMID: 30760722 PMCID: PMC6374409 DOI: 10.1038/s41467-019-08736-7] [Citation(s) in RCA: 172] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 01/23/2019] [Indexed: 01/10/2023] Open
Abstract
Understanding genomic functions requires site-specific manipulation of loci via efficient protein effector targeting systems. However, few approaches for targeted manipulation of the epigenome are available in plants. Here, we adapt the dCas9-SunTag system to engineer targeted gene activation and DNA methylation in Arabidopsis. We demonstrate that a dCas9-SunTag system utilizing the transcriptional activator VP64 drives robust and specific activation of several loci, including protein coding genes and transposable elements, in diverse chromatin contexts. In addition, we present a CRISPR-based methylation targeting system for plants, utilizing a SunTag system with the catalytic domain of the Nicotiana tabacum DRM methyltransferase, which efficiently targets DNA methylation to specific loci, including the FWA promoter, triggering a developmental phenotype, and the SUPERMAN promoter. These SunTag systems represent valuable tools for the site-specific manipulation of plant epigenomes.
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34
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Cell-Based Model of the Generation and Maintenance of the Shape and Structure of the Multilayered Shoot Apical Meristem of Arabidopsis thaliana. Bull Math Biol 2018; 81:3245-3281. [PMID: 30552627 DOI: 10.1007/s11538-018-00547-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 11/28/2018] [Indexed: 01/28/2023]
Abstract
One of the central problems in animal and plant developmental biology is deciphering how chemical and mechanical signals interact within a tissue to produce organs of defined size, shape, and function. Cell walls in plants impose a unique constraint on cell expansion since cells are under turgor pressure and do not move relative to one another. Cell wall extensibility and constantly changing distribution of stress on the wall are mechanical properties that vary between individual cells and contribute to rates of expansion and orientation of cell division. How exactly cell wall mechanical properties influence cell behavior is still largely unknown. To address this problem, a novel, subcellular element computational model of growth of stem cells within the multilayered shoot apical meristem (SAM) of Arabidopsis thaliana is developed and calibrated using experimental data. Novel features of the model include separate, detailed descriptions of cell wall extensibility and mechanical stiffness, deformation of the middle lamella, and increase in cytoplasmic pressure generating internal turgor pressure. The model is used to test novel hypothesized mechanisms of formation of the shape and structure of the growing, multilayered SAM based on WUS concentration of individual cells controlling cell growth rates and layer-dependent anisotropic mechanical properties of subcellular components of individual cells determining anisotropic cell expansion directions. Model simulations also provide a detailed prediction of distribution of stresses in the growing tissue which can be tested in future experiments.
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35
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Kuluev B, Avalbaev A, Nikonorov Y, Ermoshin A, Yuldashev R, Akhiarova G, Shakirova F, Chemeris A. Effect of constitutive expression of Arabidopsis CLAVATA3 on cell growth and possible role of cytokinins in leaf size control in transgenic tobacco plants. JOURNAL OF PLANT PHYSIOLOGY 2018; 231:244-250. [PMID: 30317073 DOI: 10.1016/j.jplph.2018.09.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 09/17/2018] [Accepted: 09/18/2018] [Indexed: 06/08/2023]
Abstract
We generated transgenic tobacco plants (Nicotiana tabacum L.) with overexpression of the Arabidopsis thaliana CLAVATA3 (CLV3) gene which is known to be a negative regulator of cell division. Surprisingly, most of the 35S::CLV3 transgenic plants showed no phenotypic differences with the wild type plants. However, there were considerable changes in the morphological parameters between 35S::CLV3 overexpressors and wild type plants. As expected, the number of meristematic cells in the shoot apical meristem was reduced in 35S::CLV3 plants as compared to the wild type plants. Moreover, overexpression of CLV3 exerted morphological changes not only to shoot apical meristem but also to leaves and flowers. Thus, transgenic plants were characterized by reduced number of epidermal and mesophyll cells as well as stomatal pores in mature leaves. However, there was a compensatory increase in leaf cell size of 35S::CLV3 plants that contributed to maintenance of organ size within the normal range. We observed that expression of cell expansion-promoted genes, expansin NtEXPA4 and endo-xyloglucan transferase NtEXGT, were elevated in mature leaves. In contrast, there was a decrease in the transcript level of the cell division-related AINTEGUMENTA-like (NtANTL) gene in 35S::CLV3 transgenic plants. In addition, we detected an increase in cytokinin level without any changes in the contents of IAA and ABA in 35S::CLV3 overexpressors. Interestingly, cytokinin treatment was shown to stimulate the expression of NtEXPA4 and NtEXGT genes in 35S::CLV3 transgenic plants. We propose that observed compensatory cell expansion in leaves of 35S::CLV3 transgenic plants may be due, at least in part, to a possible link between cytokinin signalling and cell expansion-related genes.
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Affiliation(s)
- Bulat Kuluev
- Institute of Biochemistry and Genetics - Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, 450054 Ufa, Russia.
| | - Azamat Avalbaev
- Institute of Biochemistry and Genetics - Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, 450054 Ufa, Russia.
| | - Yuri Nikonorov
- Institute of Biochemistry and Genetics - Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, 450054 Ufa, Russia
| | - Alexander Ermoshin
- Institute of Natural Sciences, Ural Federal University, 620002, Yekaterinburg, Russia
| | - Ruslan Yuldashev
- Institute of Biochemistry and Genetics - Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, 450054 Ufa, Russia
| | - Guzel Akhiarova
- Ufa Institute of Biology - Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, 450054, Ufa, Russia
| | - Farida Shakirova
- Institute of Biochemistry and Genetics - Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, 450054 Ufa, Russia
| | - Aleksey Chemeris
- Institute of Biochemistry and Genetics - Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, 450054 Ufa, Russia
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Gruel J, Deichmann J, Landrein B, Hitchcock T, Jönsson H. The interaction of transcription factors controls the spatial layout of plant aerial stem cell niches. NPJ Syst Biol Appl 2018; 4:36. [PMID: 30210806 PMCID: PMC6127332 DOI: 10.1038/s41540-018-0072-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 07/25/2018] [Accepted: 07/31/2018] [Indexed: 12/31/2022] Open
Abstract
The plant shoot apical meristem holds a stem cell niche from which all aerial organs originate. Using a computational approach we show that a mixture of monomers and heterodimers of the transcription factors WUSCHEL and HAIRY MERISTEM is sufficient to pattern the stem cell niche, and predict that immobile heterodimers form a regulatory "pocket" surrounding the stem cells. The model achieves to reproduce an array of perturbations, including mutants and tissue size modifications. We also show its ability to reproduce the recently observed dynamical shift of the stem cell niche during the development of an axillary meristem. The work integrates recent experimental results to answer the longstanding question of how the asymmetry of expression between the stem cell marker CLAVATA3 and its activator WUSCHEL is achieved, and recent findings of plasticity in the system.
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Affiliation(s)
- Jérémy Gruel
- 1Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR UK
| | - Julia Deichmann
- 1Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR UK
| | - Benoit Landrein
- 1Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR UK
| | - Thomas Hitchcock
- 1Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR UK
| | - Henrik Jönsson
- 1Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR UK.,2Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, CB3 0DZ UK.,3Computational Biology and Biological Physics, Lund University, 223 62 Lund, Sweden
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Zhou Y, Yan A, Han H, Li T, Geng Y, Liu X, Meyerowitz EM. HAIRY MERISTEM with WUSCHEL confines CLAVATA3 expression to the outer apical meristem layers. Science 2018; 361:502-506. [PMID: 30072538 PMCID: PMC6095697 DOI: 10.1126/science.aar8638] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 06/19/2018] [Indexed: 12/29/2022]
Abstract
The control of the location and activity of stem cells depends on spatial regulation of gene activities in the stem cell niche. Using computational and experimental approaches, we have tested and found support for a hypothesis for gene interactions that specify the Arabidopsis apical stem cell population. The hypothesis explains how the WUSCHEL gene product, synthesized basally in the meristem, induces CLAVATA3-expressing stem cells in the meristem apex but, paradoxically, not in the basal domain where WUSCHEL itself is expressed. The answer involves the activity of the small family of HAIRY MERISTEM genes, which prevent the activation of CLAVATA3 and which are expressed basally in the shoot meristem.
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Affiliation(s)
- Yun Zhou
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - An Yan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Han Han
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Ting Li
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Yuan Geng
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Xing Liu
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Elliot M Meyerowitz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
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Shi B, Guo X, Wang Y, Xiong Y, Wang J, Hayashi KI, Lei J, Zhang L, Jiao Y. Feedback from Lateral Organs Controls Shoot Apical Meristem Growth by Modulating Auxin Transport. Dev Cell 2018; 44:204-216.e6. [PMID: 29401419 DOI: 10.1016/j.devcel.2017.12.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 10/31/2017] [Accepted: 12/20/2017] [Indexed: 12/23/2022]
Abstract
Stem cells must balance self-renewal and differentiation; thus, their activities are precisely controlled. In plants, the control circuits that underlie division and differentiation within meristems have been well studied, but those that underlie feedback on meristems from lateral organs remain largely unknown. Here we show that long-distance auxin transport mediates this feedback in a non-cell-autonomous manner. A low-auxin zone is associated with the shoot apical meristem (SAM) organization center, and auxin levels negatively affect SAM size. Using computational model simulations, we show that auxin transport from lateral organs can inhibit auxin transport from the SAM through an auxin transport switch and thus maintain SAM auxin homeostasis and SAM size. Genetic and microsurgical analyses confirmed the model's predictions. In addition, the model explains temporary change in SAM size of yabby mutants. Our study suggests that the canalization-based auxin flux can be widely adapted as a feedback control mechanism in plants.
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Affiliation(s)
- Bihai Shi
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaolu Guo
- Beijing International Center for Mathematical Research, Peking University, Beijing 100871, China
| | - Ying Wang
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuanyuan Xiong
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jin Wang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ken-Ichiro Hayashi
- Department of Biochemistry, Okayama University of Science, Okayama 700-0005, Japan
| | - Jinzhi Lei
- Zhou Pei-Yuan Center for Applied Mathematics, Tsinghua University, Beijing 100084, China
| | - Lei Zhang
- Beijing International Center for Mathematical Research, Peking University, Beijing 100871, China; Center for Quantitative Biology, Peking University, Beijing 100871, China.
| | - Yuling Jiao
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
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Abstract
In contrast to animals, plants maintain life-long post-embryonic organogenesis from specialized tissues termed meristems. Shoot meristems give rise to all aerial tissues and are precisely regulated to balance stem cell renewal and differentiation. The phytohormone auxin has a dynamic and differential distribution within shoot meristems and during shoot meristem formation. Polar auxin transport and local auxin biosynthesis lead to auxin maxima and minima to direct cell fate specification, which are critical for meristem formation, lateral organ formation, and lateral organ patterning. In recent years, feedback regulatory loops of auxin transport and signaling have emerged as major determinants of the self-organizing properties of shoot meristems. Systems biology approaches, which involve molecular genetics, live imaging, and computational modeling, have become increasingly important to unravel the function of auxin signaling in shoot meristems.
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Affiliation(s)
- Ying Wang
- College of Life Sciences, University of Chinese Academy of Sciences, China
| | - Yuling Jiao
- College of Life Sciences, University of Chinese Academy of Sciences, China
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, China
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Abstract
Shoot meristems are maintained by pluripotent stem cells that are controlled by CLAVATA-WUSCHEL feedback signaling. This pathway, which coordinates stem cell proliferation with differentiation, was first identified in Arabidopsis, but appears to be conserved in diverse higher plant species. In this Review, we highlight the commonalities and differences between CLAVATA-WUSCHEL pathways in different species, with an emphasis on Arabidopsis, maize, rice and tomato. We focus on stem cell control in shoot meristems, but also briefly discuss the role of these signaling components in root meristems.
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Affiliation(s)
- Marc Somssich
- Heinrich-Heine-University, Düsseldorf D-40225, Germany
| | - Byoung Il Je
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Rüdiger Simon
- Heinrich-Heine-University, Düsseldorf D-40225, Germany
| | - David Jackson
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
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Bakshi A, Moin M, Datla R, Kirti PB. Expression profiling of development related genes in rice plants ectopically expressing AtTOR. PLANT SIGNALING & BEHAVIOR 2017; 12:e1362519. [PMID: 28816596 PMCID: PMC5640186 DOI: 10.1080/15592324.2017.1362519] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 07/27/2017] [Indexed: 05/19/2023]
Abstract
Expression analysis of genes associated with development at different growth stages such as shoot apical meristem (SAM), root apical meristem (RAM), shoot and root tissues 10 DAG, flowers and grains of 2 high expression transgenic lines of rice ectopically expressing AtTOR revealed the involvement of AtTOR in transcriptional regulation of these genes. We have observed that in the SAM of these 2 selected lines, TR-2.24 and TR-15.1, OsFON1 and OsFON4 (orthologs of AtCLV1 and AtCLV3, respectively), OsKNOX2, OsKNOX3 and OsWOX3 became upregulated. The upregulation of OsFON1 and OsFON4 is likely to be involved in the maintenance of effective meristem size of the inflorescence and phyllotaxis. The grains and spikes of transgenic plants exhibited enhanced transcript levels of OsMADS1, OsMADS6, and OsMADS29 further implicating the role of TOR in modulating the expression of the genes in rice grain formation and development. Moreover, the upregulation of auxin transporter, PIN1c in RAM and roots derived from seedlings 10 DAG showed the involvement of TOR in root development. The seeds of 2 high expression lines also showed increased expression of OSE2 and GAMYB transcription factors involved in seed development. In summary, the present study, by heterologous expression of AtTOR in rice, demonstrated the involvement of TOR in regulating genes involved in various growth and developmental stages of rice plant and also in photosynthesis, productivity related functions and water-use efficiency.
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Affiliation(s)
- Achala Bakshi
- Department of Plant Sciences, University of Hyderabad, Hyderabad
| | - Mazahar Moin
- Department of Plant Sciences, University of Hyderabad, Hyderabad
| | - Raju Datla
- National Research Council of Canada, Saskatoon, Saskatchewan, Canada
| | - P. B. Kirti
- Department of Plant Sciences, University of Hyderabad, Hyderabad
- CONTECT P. B. Kirti Department of Plant Sciences, University of Hyderabad, Hyderabad-500046, TelanganaIndia
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Ye S, Yang W, Zhai R, Lu Y, Wang J, Zhang X. Mapping and application of the twin-grain1 gene in rice. PLANTA 2017; 245:707-716. [PMID: 27999987 DOI: 10.1007/s00425-016-2627-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 11/28/2016] [Indexed: 06/06/2023]
Abstract
The map-based cloning and application of a flower organ number gene twin - grain1 provide great potential for improving seed production in hybrid rice. A new germplasm for high-yield rice breeding, the twin-grain1 (tg1) mutant with more than one grain in a glume, was obtained from the Zhejing 22 rice variety via physical mutagenesis. The mapping results showed that TG1 is allelic to FLORAL ORGAN NUMBER2 (FON2)/FLORAL ORGAN NUMBER4 (FON4), a flower organ number gene located at 88.7 cM on chromosome 11. The novel tg1 gene allele was introgressed into the cytoplasmic male sterility (CMS) line Zhejing 22A, giving rise to a new CMS line Zhejing 22-tg1A. The Zhejing 22-tg1A line showed enhanced glume opening and stigma exsertion, which increased the outcrossing rate in hybrid rice. A small-scale hybrid rice seed production test demonstrated that the grain yield of the Zhejing 22-tg1A/Zhejinghui 5 line was significantly increased compared to that of the Zhejing 22A/Zhejinghui 5 line. The plot yield evaluation of the F1 hybrid lines showed a higher yield for the Zhejing 22-tg1A/Zhejinghui 5 line than that of the Zhejing 22A/Zhejinghui 5 line. The results implied great potentials for the tg1 gene in hybrid rice breeding.
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Affiliation(s)
- Shenghai Ye
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Weibing Yang
- Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Rongrong Zhai
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Yanting Lu
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Junmei Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Xiaoming Zhang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
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Nimchuk ZL. CLAVATA1 controls distinct signaling outputs that buffer shoot stem cell proliferation through a two-step transcriptional compensation loop. PLoS Genet 2017; 13:e1006681. [PMID: 28355208 PMCID: PMC5371295 DOI: 10.1371/journal.pgen.1006681] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/09/2017] [Indexed: 02/07/2023] Open
Abstract
The regulation of stem cell proliferation in plants is controlled by intercellular signaling pathways driven by the diffusible CLAVATA3 (CLV3p) peptide. CLV3p perception is thought to be mediated by an overlapping array of receptors in the stem cell niche including the transmembrane receptor kinase CLV1, Receptor-Like Protein Kinase 2 (RPK2), and a dimer of the receptor-like protein CLV2 and the CORYNE (CRN) pseudokinase. Mutations in these receptors have qualitatively similar effects on stem cell function but it is unclear if this represents common or divergent signaling outputs. Previous work in heterologous systems has suggested that CLV1, RPK2 and CLV2/CRN could form higher order complexes but it is also unclear what relevance these putative complexes have to in vivo receptor functions. Here I use the in vivo regulation of a specific transcriptional target of CLV1 signaling in Arabidopsis to demonstrate that, despite the phenotypic similarities between the different receptor mutants, CLV1 controls distinct signaling outputs in living stem cell niches independent of other receptors. This regulation is separable from stem cell proliferation driven by WUSCHEL, a proposed common transcriptional target of CLV3p signaling. In addition, in the absence of CLV1, CLV1-related receptor kinases are ectopically expressed but also buffer stem cell proliferation through the auto-repression of their own expression. Collectively these data reveal a unique in vivo role for CLV1 separable from other stem cell receptors and provides a framework for dissecting the signaling outputs in stem cell regulation. The proliferation of plant stem cells in above ground tissues is controlled by a suite of receptors in response to the CLAVATA3 peptide ligand. Receptor signaling in response to CLAVATA3 prevents over-proliferation of stem cells. It is unclear what the functional relationship is between the proposed CLAVATA3 receptors or if they impact common signaling outputs. Here I demonstrate that CLAVATA1 signals independently of the other receptors kinases to control distinct transcriptional outputs independent of stem cell proliferation. Stem cell proliferation is buffered by a two-step mechanism which transcriptionally regulates receptor levels in the stem cell niche. This mechanism helps explain the strict control of stem cell proliferation and could provide new avenues for improving plant growth.
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Affiliation(s)
- Zachary L. Nimchuk
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
- * E-mail:
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44
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Threshold-dependent transcriptional discrimination underlies stem cell homeostasis. Proc Natl Acad Sci U S A 2016; 113:E6298-E6306. [PMID: 27671653 DOI: 10.1073/pnas.1607669113] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Transcriptional mechanisms that underlie the dose-dependent regulation of gene expression in animal development have been studied extensively. However, the mechanisms of dose-dependent transcriptional regulation in plant development have not been understood. In Arabidopsis shoot apical meristems, WUSCHEL (WUS), a stem cell-promoting transcription factor, accumulates at a higher level in the rib meristem and at a lower level in the central zone where it activates its own negative regulator, CLAVATA3 (CLV3). How WUS regulates CLV3 levels has not been understood. Here we show that WUS binds a group of cis-elements, cis- regulatory module, in the CLV3-regulatory region, with different affinities and conformations, consisting of monomers at lower concentration and as dimers at a higher level. By deleting cis elements, manipulating the WUS-binding affinity and the homodimerization threshold of cis elements, and manipulating WUS levels, we show that the same cis elements mediate both the activation and repression of CLV3 at lower and higher WUS levels, respectively. The concentration-dependent transcriptional discrimination provides a mechanistic framework to explain the regulation of CLV3 levels that is critical for stem cell homeostasis.
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45
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DNA-dependent homodimerization, sub-cellular partitioning, and protein destabilization control WUSCHEL levels and spatial patterning. Proc Natl Acad Sci U S A 2016; 113:E6307-E6315. [PMID: 27671631 DOI: 10.1073/pnas.1607673113] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The homeodomain transcription factor WUSCHEL (WUS) promotes stem cell maintenance in inflorescence meristems of Arabidopsis thaliana WUS, which is synthesized in the rib meristem, migrates and accumulates at lower levels in adjacent cells. Maintenance of WUS protein levels and spatial patterning distribution is not well-understood. Here, we show that the last 63-aa stretch of WUS is necessary for maintaining different levels of WUS protein in the rib meristem and adjacent cells. The 63-aa region contains the following transcriptional regulatory domains: the acidic region, the WUS-box, which is conserved in WUS-related HOMEOBOX family members, and the ethylene-responsive element binding factor-associated amphiphilic repression (EAR-like) domain. Our analysis reveals that the opposing functions of WUS-box, which is required for nuclear retention, and EAR-like domain, which participates in nuclear export, are necessary to maintain higher nuclear levels of WUS in cells of the rib meristem and lower nuclear levels in adjacent cells. We also show that the N-terminal DNA binding domain, which is required for both DNA binding and homodimerization, along with the homodimerization sequence located in the central part of the protein, restricts WUS from spreading excessively and show that the homodimerization is critical for WUS function. Our analysis also reveals that a higher level of WUS outside the rib meristem leads to protein destabilization, suggesting a new tier of regulation in WUS protein regulation. Taken together our data show that processes that influence WUS protein levels and spatial distribution are highly coupled to its transcriptional activity.
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46
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Pandey DK, Chaudhary B. Domestication-driven Gossypium profilin 1 (GhPRF1) gene transduces early flowering phenotype in tobacco by spatial alteration of apical/floral-meristem related gene expression. BMC PLANT BIOLOGY 2016; 16:112. [PMID: 27177585 PMCID: PMC4866011 DOI: 10.1186/s12870-016-0798-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 05/02/2016] [Indexed: 05/26/2023]
Abstract
BACKGROUND Plant profilin genes encode core cell-wall structural proteins and are evidenced for their up-regulation under cotton domestication. Notwithstanding striking discoveries in the genetics of cell-wall organization in plants, little is explicit about the manner in which profilin-mediated molecular interplay and corresponding networks are altered, especially during cellular signalling of apical meristem determinacy and flower development. RESULTS Here we show that the ectopic expression of GhPRF1 gene in tobacco resulted in the hyperactivation of apical meristem and early flowering phenotype with increased flower number in comparison to the control plants. Spatial expression alteration in CLV1, a key meristem-determinacy gene, is induced by the GhPRF1 overexpression in a WUS-dependent manner and mediates cell signalling to promote flowering. But no such expression alterations are recorded in the GhPRF1-RNAi lines. The GhPRF1 transduces key positive flowering regulator AP1 gene via coordinated expression of FT4, SOC1, FLC1 and FT1 genes involved in the apical-to-floral meristem signalling cascade which is consistent with our in silico profilin interaction data. Remarkably, these positive and negative flowering regulators are spatially controlled by the Actin-Related Protein (ARP) genes, specifically ARP4 and ARP6 in proximate association with profilins. This study provides a novel and systematic link between GhPRF1 gene expression and the flower primordium initiation via up-regulation of the ARP genes, and an insight into the functional characterization of GhPRF1 gene acting upstream to the flowering mechanism. Also, the transgenic plants expressing GhPRF1 gene show an increase in the plant height, internode length, leaf size and plant vigor. CONCLUSIONS Overexpression of GhPRF1 gene induced early and increased flowering in tobacco with enhanced plant vigor. During apical meristem determinacy and flower development, the GhPRF1 gene directly influences key flowering regulators through ARP-genes, indicating for its role upstream in the apical-to-floral meristem signalling cascade.
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Affiliation(s)
- Dhananjay K Pandey
- School of Biotechnology, Gautam Buddha University, Greater Noida, 201310, UP, India
| | - Bhupendra Chaudhary
- School of Biotechnology, Gautam Buddha University, Greater Noida, 201310, UP, India.
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Li S, Pan Y, Wen C, Li Y, Liu X, Zhang X, Behera TK, Xing G, Weng Y. Integrated analysis in bi-parental and natural populations reveals CsCLAVATA3 (CsCLV3) underlying carpel number variations in cucumber. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2016; 129:1007-22. [PMID: 26883041 DOI: 10.1007/s00122-016-2679-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Accepted: 01/23/2016] [Indexed: 05/26/2023]
Abstract
Carpel number variation in cucumber was controlled by a single gene, Cn . Linkage and association analysis revealed CsCLV3 as the candidate gene of the Cn locus. Carpel number (CN) is an important fruit quality trait of cucumber, but the genetic basis of CN variations is largely unknown. In the present study, segregating analysis in multiple bi-parental mapping populations (F2, F3, and RILs) derived from WI2757 (CN = 3) × True Lemon (CN = 5) suggested that CN is controlled by a simply inherited gene, Cn, with CN = 3 being incompletely dominant to CN = 5. Initial linkage mapping located Cn in a 1.9-Mb region of cucumber chromosome 1. Exploration of DNA sequence variations in this region with in silico bulked segregant analysis among eight re-sequenced lines allowed delimiting the Cn locus to a 16-kb region with five predicted genes including CsCLV3, a homolog of the Arabidopsis gene CLAVATA3. Fine genetic mapping in F2 and RIL populations and association analysis in natural populations confirmed CsCLV3 as the candidate gene for Cn, which was further evidenced from gene expression analysis and microscopic examination of floral meristem size in the two parent lines. This study highlights the importance of integrated use of linkage and association analysis as well as next-gen high-throughput sequencing in mapping and cloning genes that are difficult in accurate genotyping. The results provide new insights into the genetic control of CN variations in cucumber, which were discussed in the context of the well-characterized CLAVATA pathway for stem cell homeostasis and regulation of meristem sizes in plants. The associations of carpel number with fruit shape, size, and weight in cucumber and melon are also discussed.
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Affiliation(s)
- Sen Li
- Horticulture College, Shanxi Agricultural University, Taigu, 030801, China
- Horticulture Department, University of Wisconsin, Madison, WI, 53706, USA
| | - Yupeng Pan
- Horticulture Department, University of Wisconsin, Madison, WI, 53706, USA
- Horticulture College, Northwest A&F University, Yangling, 712100, China
| | - Changlong Wen
- Horticulture Department, University of Wisconsin, Madison, WI, 53706, USA
- Beijing Vegetable Research Center and National Engineering Research Center for Vegetables, Beijing Academy of Agricultural and Forestry Sciences, Beijing, 100097, China
| | - Yuhong Li
- Horticulture Department, University of Wisconsin, Madison, WI, 53706, USA
- Horticulture College, Northwest A&F University, Yangling, 712100, China
| | - Xiaofeng Liu
- Department of Vegetable Sciences, China Agricultural University, Beijing, 100193, China
| | - Xiaolan Zhang
- Department of Vegetable Sciences, China Agricultural University, Beijing, 100193, China
| | - Tusar K Behera
- Division of Vegetable Science, Indian Agricultural Research Institute, New Delhi, 10012, India
| | - Guoming Xing
- Horticulture College, Shanxi Agricultural University, Taigu, 030801, China
| | - Yiqun Weng
- Horticulture Department, University of Wisconsin, Madison, WI, 53706, USA.
- USDA-ARS, Vegetable Crops Research Unit, 1575 Linden Drive, Madison, WI, 53706, USA.
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48
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Galli M, Gallavotti A. Expanding the Regulatory Network for Meristem Size in Plants. Trends Genet 2016; 32:372-383. [PMID: 27129984 DOI: 10.1016/j.tig.2016.04.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 04/01/2016] [Indexed: 11/18/2022]
Abstract
The remarkable plasticity of post-embryonic plant development is due to groups of stem-cell-containing structures called meristems. In the shoot, meristems continuously produce organs such as leaves, flowers, and stems. Nearly two decades ago the WUSCHEL/CLAVATA (WUS/CLV) negative feedback loop was established as being essential for regulating the size of shoot meristems by maintaining a delicate balance between stem cell proliferation and cell recruitment for the differentiation of lateral primordia. Recent research in various model species (Arabidopsis, tomato, maize, and rice) has led to discoveries of additional components that further refine and improve the current model of meristem regulation, adding new complexity to a vital network for plant growth and productivity.
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Affiliation(s)
- Mary Galli
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854-8020, USA
| | - Andrea Gallavotti
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854-8020, USA; Department of Plant Biology and Pathology, Rutgers University, New Brunswick, NJ, 08901, USA.
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49
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Liu Y, Yang S, Song Y, Men S, Wang J. Gain-of-function analysis of poplar CLE genes in Arabidopsis by exogenous application and over-expression assays. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:2309-24. [PMID: 26912800 DOI: 10.1093/jxb/erw045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Among 50 CLE gene family members in the Populus trichocarpa genome, three and six PtCLE genes encode a CLE motif sequence highly homologous to Arabidopsis CLV3 and TDIF peptides, respectively, which potentially make them functional equivalents. To test and compare their biological activity, we first chemically synthesized each dodecapeptide and analysed itsi n vitro bioactivity on Arabidopsis seedlings. Similarly, but to a different extent, three types of poplar CLV3-related peptides caused root meristem consumption, phyllotaxis disorder, anthocyanin accumulation and failure to enter the bolting stage. In comparison, application of two poplar TDIF-related peptides led to root length promotion in a dose-dependent manner with an even stronger effect observed for poplar TDIF-like peptide than TDIF. Next, we constructed CaMV35S:PtCLE transgenic plants for each of the nine PtCLE genes. Phenotypic abnormalities exemplified by arrested shoot apical meristem and abnormal flower structure were found to be more dominant and severe in 35S:PtCLV3 and 35S:PtCLV3-like2 lines than in the 35S:PtCLV3-like line. Disordered vasculature was detected in both stem and hypocotyl cross-sections in Arabidopsis plants over-expressing poplar TDIF-related genes with the most defective vascular patterning observed for TDIF2 and two TDIF-like genes. Phenotypic difference consistently observed in peptide application assay and transgenic analysis indicated the functional diversity of nine poplar PtCLE genes under investigation. This work represents the first report on the functional analysis of CLE genes in a tree species and constitutes a basis for further study of the CLE peptide signalling pathway in tree development.
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Affiliation(s)
- Yisen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Shaohui Yang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yingjin Song
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Shuzhen Men
- College of Life Sciences, Nankai University, Tianjin 300072, China
| | - Jiehua Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
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50
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Mestek Boukhibar L, Barkoulas M. The developmental genetics of biological robustness. ANNALS OF BOTANY 2016; 117:699-707. [PMID: 26292993 PMCID: PMC4845795 DOI: 10.1093/aob/mcv128] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 05/07/2015] [Accepted: 06/29/2015] [Indexed: 05/10/2023]
Abstract
BACKGROUND Living organisms are continuously confronted with perturbations, such as environmental changes that include fluctuations in temperature and nutrient availability, or genetic changes such as mutations. While some developmental systems are affected by such challenges and display variation in phenotypic traits, others continue consistently to produce invariable phenotypes despite perturbation. This ability of a living system to maintain an invariable phenotype in the face of perturbations is termed developmental robustness. Biological robustness is a phenomenon observed across phyla, and studying its mechanisms is central to deciphering the genotype-phenotype relationship. Recent work in yeast, animals and plants has shown that robustness is genetically controlled and has started to reveal the underlying mechinisms behind it. SCOPE AND CONCLUSIONS Studying biological robustness involves focusing on an important property of developmental traits, which is the phenotypic distribution within a population. This is often neglected because the vast majority of developmental biology studies instead focus on population aggregates, such as trait averages. By drawing on findings in animals and yeast, this Viewpoint considers how studies on plant developmental robustness may benefit from strict definitions of what is the developmental system of choice and what is the relevant perturbation, and also from clear distinctions between gene effects on the trait mean and the trait variance. Recent advances in quantitative developmental biology and high-throughput phenotyping now allow the design of targeted genetic screens to identify genes that amplify or restrict developmental trait variance and to study how variation propagates across different phenotypic levels in biological systems. The molecular characterization of more quantitative trait loci affecting trait variance will provide further insights into the evolution of genes modulating developmental robustness. The study of robustness mechanisms in closely related species will address whether mechanisms of robustness are evolutionarily conserved.
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Affiliation(s)
- Lamia Mestek Boukhibar
- Imperial College London, Department of Life Sciences, Sir Alexander Fleming Building, South Kensington Campus, London SW7 2AZ, UK
| | - Michalis Barkoulas
- Imperial College London, Department of Life Sciences, Sir Alexander Fleming Building, South Kensington Campus, London SW7 2AZ, UK
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