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Hu ZL, Wilson-Sánchez D, Bhatia N, Rast-Somssich MI, Wu A, Vlad D, McGuire L, Nikolov LA, Laufs P, Gan X, Laurent S, Runions A, Tsiantis M. A CUC1/auxin genetic module links cell polarity to patterned tissue growth and leaf shape diversity in crucifer plants. Proc Natl Acad Sci U S A 2024; 121:e2321877121. [PMID: 38905239 PMCID: PMC11214078 DOI: 10.1073/pnas.2321877121] [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: 12/22/2023] [Accepted: 05/08/2024] [Indexed: 06/23/2024] Open
Abstract
How tissue-level information encoded by fields of regulatory gene activity is translated into the patterns of cell polarity and growth that generate the diverse shapes of different species remains poorly understood. Here, we investigate this problem in the case of leaf shape differences between Arabidopsis thaliana, which has simple leaves, and its relative Cardamine hirsuta that has complex leaves divided into leaflets. We show that patterned expression of the transcription factor CUP-SHAPED COTYLEDON1 in C. hirsuta (ChCUC1) is a key determinant of leaf shape differences between the two species. Through inducible genetic perturbations, time-lapse imaging of growth, and computational modeling, we find that ChCUC1 provides instructive input into auxin-based leaf margin patterning. This input arises via transcriptional regulation of multiple auxin homeostasis components, including direct activation of WAG kinases that are known to regulate the polarity of PIN-FORMED auxin transporters. Thus, we have uncovered a mechanism that bridges biological scales by linking spatially distributed and species-specific transcription factor expression to cell-level polarity and growth, to shape diverse leaf forms.
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Affiliation(s)
- Zi-Liang Hu
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne50829, Germany
| | - David Wilson-Sánchez
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne50829, Germany
| | - Neha Bhatia
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne50829, Germany
| | - Madlen I. Rast-Somssich
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne50829, Germany
| | - Anhui Wu
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne50829, Germany
| | - Daniela Vlad
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne50829, Germany
| | - Liam McGuire
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne50829, Germany
| | - Lachezar A. Nikolov
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne50829, Germany
| | - Patrick Laufs
- Université Paris-Saclay, Institut national de recherche pour l’agriculture, l’alimentation et l’environnement, AgroParisTech, Institut Jean-Pierre Bourgin, Versailles78000, France
| | - Xiangchao Gan
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne50829, Germany
| | - Stefan Laurent
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne50829, Germany
| | - Adam Runions
- Department of Computer Science, University of Calgary, Calgary, ABT2N 1N4, Canada
| | - Miltos Tsiantis
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne50829, Germany
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2
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Sessa G, Carabelli M, Sassi M. The Ins and Outs of Homeodomain-Leucine Zipper/Hormone Networks in the Regulation of Plant Development. Int J Mol Sci 2024; 25:5657. [PMID: 38891845 PMCID: PMC11171833 DOI: 10.3390/ijms25115657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 05/20/2024] [Accepted: 05/21/2024] [Indexed: 06/21/2024] Open
Abstract
The generation of complex plant architectures depends on the interactions among different molecular regulatory networks that control the growth of cells within tissues, ultimately shaping the final morphological features of each structure. The regulatory networks underlying tissue growth and overall plant shapes are composed of intricate webs of transcriptional regulators which synergize or compete to regulate the expression of downstream targets. Transcriptional regulation is intimately linked to phytohormone networks as transcription factors (TFs) might act as effectors or regulators of hormone signaling pathways, further enhancing the capacity and flexibility of molecular networks in shaping plant architectures. Here, we focus on homeodomain-leucine zipper (HD-ZIP) proteins, a class of plant-specific transcriptional regulators, and review their molecular connections with hormonal networks in different developmental contexts. We discuss how HD-ZIP proteins emerge as key regulators of hormone action in plants and further highlight the fundamental role that HD-ZIP/hormone networks play in the control of the body plan and plant growth.
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Affiliation(s)
| | | | - Massimiliano Sassi
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, 00185 Rome, Italy; (G.S.); (M.C.)
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Choudury SG, Husbands AY. Pick a side: Integrating gene expression and mechanical forces to polarize aerial organs. CURRENT OPINION IN PLANT BIOLOGY 2023; 76:102460. [PMID: 37775406 DOI: 10.1016/j.pbi.2023.102460] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/25/2023] [Accepted: 09/01/2023] [Indexed: 10/01/2023]
Abstract
How organs acquire their shapes is a central question in developmental biology. In plants, aerial lateral organs such as leaves initiate at the flanks of the growing meristem as dome-shaped primordia. These simple structures then grow out along multiple polarity axes to achieve a dizzying array of final shapes. Many of the hormone signaling pathways and genetic interactions that influence growth along these axes have been identified in the past few decades. Open questions include how and when initial gene expression patterns are set in organ primordia, and how these patterns are translated into the physical outcomes observed at the cellular and tissue levels. In this review, we highlight recent studies into the auxin signaling and gene expression dynamics that govern adaxial-abaxial patterning, and the contributions of mechanical forces to the development of flattened structures.
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Affiliation(s)
- Sarah G Choudury
- Department of Biology, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Aman Y Husbands
- Department of Biology, University of Pennsylvania, Philadelphia PA 19104, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia PA 19104, USA.
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Holloway DM, Saunders R, Wenzel CL. Size regulation of the lateral organ initiation zone and its role in determining cotyledon number in conifers. FRONTIERS IN PLANT SCIENCE 2023; 14:1166226. [PMID: 37265639 PMCID: PMC10230826 DOI: 10.3389/fpls.2023.1166226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/03/2023] [Indexed: 06/03/2023]
Abstract
Introduction Unlike monocots and dicots, many conifers, particularly Pinaceae, form three or more cotyledons. These are arranged in a whorl, or ring, at a particular distance from the embryo tip, with cotyledons evenly spaced within the ring. The number of cotyledons, nc, varies substantially within species, both in clonal cultures and in seed embryos. nc variability reflects embryo size variability, with larger diameter embryos having higher nc. Correcting for growth during embryo development, we extract values for the whorl radius at each nc. This radius, corresponding to the spatial pattern of cotyledon differentiation factors, varies over three-fold for the naturally observed range of nc. The current work focuses on factors in the patterning mechanism that could produce such a broad variability in whorl radius. Molecularly, work in Arabidopsis has shown that the initiation zone for leaf primordia occurs at a minimum between inhibitor zones of HD-ZIP III at the shoot apical meristem (SAM) tip and KANADI (KAN) encircling this farther from the tip. PIN1-auxin dynamics within this uninhibited ring form auxin maxima, specifying primordia initiation sites. A similar mechanism is indicated in conifer embryos by effects on cotyledon formation with overexpression of HD-ZIP III inhibitors and by interference with PIN1-auxin patterning. Methods We develop a mathematical model for HD-ZIP III/KAN spatial localization and use this to characterize the molecular regulation that could generate (a) the three-fold whorl radius variation (and associated nc variability) observed in conifer cotyledon development, and (b) the HD-ZIP III and KAN shifts induced experimentally in conifer embryos and in Arabidopsis. Results This quantitative framework indicates the sensitivity of mechanism components for positioning lateral organs closer to or farther from the tip. Positional shifting is most readily driven by changes to the extent of upstream (meristematic) patterning and changes in HD-ZIP III/KAN mutual inhibition, and less efficiently driven by changes in upstream dosage or the activation of HD-ZIP III. Sharper expression boundaries can also be more resistant to shifting than shallower expression boundaries. Discussion The strong variability seen in conifer nc (commonly from 2 to 10) may reflect a freer variation in regulatory interactions, whereas monocot (nc = 1) and dicot (nc = 2) development may require tighter control of such variation. These results provide direction for future quantitative experiments on the positional control of lateral organ initiation, and consequently on plant phyllotaxy and architecture.
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Affiliation(s)
- David M. Holloway
- Mathematics Department, British Columbia Institute of Technology, Burnaby, BC, Canada
| | - Rebecca Saunders
- Biotechnology Department, British Columbia Institute of Technology, Burnaby, BC, Canada
| | - Carol L. Wenzel
- Biotechnology Department, British Columbia Institute of Technology, Burnaby, BC, Canada
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Fujiwara M, Imamura M, Matsushita K, Roszak P, Yamashino T, Hosokawa Y, Nakajima K, Fujimoto K, Miyashima S. Patterned proliferation orients tissue-wide stress to control root vascular symmetry in Arabidopsis. Curr Biol 2023; 33:886-898.e8. [PMID: 36787744 DOI: 10.1016/j.cub.2023.01.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 11/24/2022] [Accepted: 01/18/2023] [Indexed: 02/16/2023]
Abstract
Symmetric tissue alignment is pivotal to the functions of plant vascular tissue, such as long-distance molecular transport and lateral organ formation. During the vascular development of the Arabidopsis roots, cytokinins initially determine cell-type boundaries among vascular stem cells and subsequently promote cell proliferation to establish vascular tissue symmetry. Although it is unknown whether and how the symmetry of initially defined boundaries is progressively refined under tissue growth in plants, such boundary shapes in animal tissues are regulated by cell fluidity, e.g., cell migration and intercalation, lacking in plant tissues. Here, we uncover that cell proliferation during vascular development produces anisotropic compressive stress, smoothing, and symmetrizing cell arrangement of the vascular-cell-type boundary. Mechanistically, the GATA transcription factor HANABA-TARANU cooperates with the type-B Arabidopsis response regulators to form an incoherent feedforward loop in cytokinin signaling. The incoherent feedforward loop fine-tunes the position and frequency of vascular cell proliferation, which in turn restricts the source of mechanical stress to the position distal and symmetric to the boundary. By combinatorial analyses of mechanical simulations and laser cell ablation, we show that the spatially constrained environment of vascular tissue efficiently entrains the stress orientation among the cells to produce a tissue-wide stress field. Together, our data indicate that the localized proliferation regulated by the cytokinin signaling circuit is decoded into a globally oriented mechanical stress to shape the vascular tissue symmetry, representing a reasonable mechanism controlling the boundary alignment and symmetry in tissue lacking cell fluidity.
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Affiliation(s)
- Motohiro Fujiwara
- Department of Biological Sciences, Graduate School of Science, Osaka University, Machikaneyama-cho, Toyonaka 560-0043, Japan
| | - Miyu Imamura
- Laboratory of Molecular and Functional Genomics, Graduate School of Bioagricultural Sciences, Nagoya University, Furocho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Katsuyoshi Matsushita
- Department of Biological Sciences, Graduate School of Science, Osaka University, Machikaneyama-cho, Toyonaka 560-0043, Japan
| | - Pawel Roszak
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, United Kingdom; Faculty of Biological and Environmental Sciences, University of Helsinki 00014, Helsinki, Finland
| | - Takafumi Yamashino
- Laboratory of Molecular and Functional Genomics, Graduate School of Bioagricultural Sciences, Nagoya University, Furocho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Yoichiroh Hosokawa
- Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Keiji Nakajima
- Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Koichi Fujimoto
- Department of Biological Sciences, Graduate School of Science, Osaka University, Machikaneyama-cho, Toyonaka 560-0043, Japan.
| | - Shunsuke Miyashima
- Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan.
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Morphogenesis of leaves: from initiation to the production of diverse shapes. Biochem Soc Trans 2023; 51:513-525. [PMID: 36876869 DOI: 10.1042/bst20220678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 02/04/2023] [Accepted: 02/16/2023] [Indexed: 03/07/2023]
Abstract
The manner by which plant organs gain their shape is a longstanding question in developmental biology. Leaves, as typical lateral organs, are initiated from the shoot apical meristem that harbors stem cells. Leaf morphogenesis is accompanied by cell proliferation and specification to form the specific 3D shapes, with flattened lamina being the most common. Here, we briefly review the mechanisms controlling leaf initiation and morphogenesis, from periodic initiation in the shoot apex to the formation of conserved thin-blade and divergent leaf shapes. We introduce both regulatory gene patterning and biomechanical regulation involved in leaf morphogenesis. How phenotype is determined by genotype remains largely unanswered. Together, these new insights into leaf morphogenesis resolve molecular chains of events to better aid our understanding.
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Abstract
Understanding the mechanism by which patterned gene activity leads to mechanical deformation of cells and tissues to create complex forms is a major challenge for developmental biology. Plants offer advantages for addressing this problem because their cells do not migrate or rearrange during morphogenesis, which simplifies analysis. We synthesize results from experimental analysis and computational modeling to show how mechanical interactions between cellulose fibers translate through wall, cell, and tissue levels to generate complex plant tissue shapes. Genes can modify mechanical properties and stresses at each level, though the values and pattern of stresses differ from one level to the next. The dynamic cellulose network provides elastic resistance to deformation while allowing growth through fiber sliding, which enables morphogenesis while maintaining mechanical strength.
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Affiliation(s)
- Enrico Coen
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Colney Lane, Norwich NR4 7UH, UK
| | - Daniel J Cosgrove
- Department of Biology, Pennsylvania State University, University Park, PA 16870, USA
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Perico C, Tan S, Langdale JA. Developmental regulation of leaf venation patterns: monocot versus eudicots and the role of auxin. THE NEW PHYTOLOGIST 2022; 234:783-803. [PMID: 35020214 PMCID: PMC9994446 DOI: 10.1111/nph.17955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Organisation and patterning of the vascular network in land plants varies in different taxonomic, developmental and environmental contexts. In leaves, the degree of vascular strand connectivity influences both light and CO2 harvesting capabilities as well as hydraulic capacity. As such, developmental mechanisms that regulate leaf venation patterning have a direct impact on physiological performance. Development of the leaf venation network requires the specification of procambial cells within the ground meristem of the primordium and subsequent proliferation and differentiation of the procambial lineage to form vascular strands. An understanding of how diverse venation patterns are manifest therefore requires mechanistic insight into how procambium is dynamically specified in a growing leaf. A role for auxin in this process was identified many years ago, but questions remain. In this review we first provide an overview of the diverse venation patterns that exist in land plants, providing an evolutionary perspective. We then focus on the developmental regulation of leaf venation patterns in angiosperms, comparing patterning in eudicots and monocots, and the role of auxin in each case. Although common themes emerge, we conclude that the developmental mechanisms elucidated in eudicots are unlikely to fully explain how parallel venation patterns in monocot leaves are elaborated.
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Affiliation(s)
- Chiara Perico
- Department of Plant SciencesUniversity of OxfordSouth Parks RdOxfordOX1 3RBUK
| | - Sovanna Tan
- Department of Plant SciencesUniversity of OxfordSouth Parks RdOxfordOX1 3RBUK
| | - Jane A. Langdale
- Department of Plant SciencesUniversity of OxfordSouth Parks RdOxfordOX1 3RBUK
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