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Uzair M, Urquidi Camacho RA, Liu Z, Overholt AM, DeGennaro D, Zhang L, Herron BS, Hong T, Shpak ED. An updated model of shoot apical meristem regulation by ERECTA family and CLAVATA3 signaling pathways in Arabidopsis. Development 2024; 151:dev202870. [PMID: 38814747 PMCID: PMC11234387 DOI: 10.1242/dev.202870] [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: 03/15/2024] [Accepted: 05/16/2024] [Indexed: 06/01/2024]
Abstract
The shoot apical meristem (SAM) gives rise to the aboveground organs of plants. The size of the SAM is relatively constant due to the balance between stem cell replenishment and cell recruitment into new organs. In angiosperms, the transcription factor WUSCHEL (WUS) promotes stem cell proliferation in the central zone of the SAM. WUS forms a negative feedback loop with a signaling pathway activated by CLAVATA3 (CLV3). In the periphery of the SAM, the ERECTA family receptors (ERfs) constrain WUS and CLV3 expression. Here, we show that four ligands of ERfs redundantly inhibit the expression of these two genes. Transcriptome analysis confirmed that WUS and CLV3 are the main targets of ERf signaling and uncovered new ones. Analysis of promoter reporters indicated that the WUS expression domain mostly overlaps with the CLV3 domain and does not shift along the apical-basal axis in clv3 mutants. Our three-dimensional mathematical model captured gene expression distributions at the single-cell level under various perturbed conditions. Based on our findings, CLV3 regulates cellular levels of WUS mostly through autocrine signaling, and ERfs regulate the spatial expression of WUS, preventing its encroachment into the peripheral zone.
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Affiliation(s)
- Muhammad Uzair
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | | | - Ziyi Liu
- UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, USA
| | - Alex M. Overholt
- 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
| | - Liang Zhang
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Brittani S. Herron
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Tian Hong
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
- UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, USA
| | - Elena D. Shpak
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
- UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, USA
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2
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Capel-Timms I, Levinson D, Lahoorpoor B, Bonetti S, Manoli G. The angiogenic growth of cities. J R Soc Interface 2024; 21:20230657. [PMID: 38565159 PMCID: PMC10987239 DOI: 10.1098/rsif.2023.0657] [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: 11/08/2023] [Accepted: 03/04/2024] [Indexed: 04/04/2024] Open
Abstract
Describing the space-time evolution of urban population is a fundamental challenge in the science of cities, yet a complete theoretical treatment of the underlying dynamics is still missing. Here, we first reconstruct the evolution of London (UK) over 180 years and show that urban growth consists of an initial phase of diffusion-limited growth, followed by the development of the railway transport network and a consequential shift from central to suburban living. Such dynamics-which are analogous to angiogenesis in biological systems-can be described by a minimalist reaction-diffusion model coupled with economic constraints and an adaptive transport network. We then test the generality of our approach by reproducing the evolution of Sydney, Australia, from 1851 to 2011. We show that the rail system coevolves with urban population, displaying hierarchical characteristics that remain constant over time unless large-scale interventions are put in place to alter the modes of transport. These results demonstrate that transport schemes are first-order controls of long-term urbanization patterns and efforts aimed at creating more sustainable and healthier cities require careful consideration of population-transport feedbacks.
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Affiliation(s)
- Isabella Capel-Timms
- Department of Civil, Environmental and Geomatic Engineering, University College London, London, UK
| | - David Levinson
- School of Civil Engineering, University of Sydney, Sydney, Australia
| | - Bahman Lahoorpoor
- School of Civil Engineering, University of Sydney, Sydney, Australia
| | - Sara Bonetti
- Laboratory of Catchment Hydrology and Geomorphology, École Polytechnique Fédérale de Lausanne, Sion, Switzerland
| | - Gabriele Manoli
- Department of Civil, Environmental and Geomatic Engineering, University College London, London, UK
- Laboratory of Urban and Environmental Systems, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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3
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Coen E, Prusinkiewicz P. Developmental timing in plants. Nat Commun 2024; 15:2674. [PMID: 38531864 PMCID: PMC10965974 DOI: 10.1038/s41467-024-46941-1] [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: 10/31/2023] [Accepted: 03/13/2024] [Indexed: 03/28/2024] Open
Abstract
Plants exhibit reproducible timing of developmental events at multiple scales, from switches in cell identity to maturation of the whole plant. Control of developmental timing likely evolved for similar reasons that humans invented clocks: to coordinate events. However, whereas clocks are designed to run independently of conditions, plant developmental timing is strongly dependent on growth and environment. Using simplified models to convey key concepts, we review how growth-dependent and inherent timing mechanisms interact with the environment to control cyclical and progressive developmental transitions in plants.
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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.
| | - Przemyslaw Prusinkiewicz
- Department of Computer Science, University of Calgary, 2500 University Dr. N.W., Calgary, AB, T2N 1N4, Canada.
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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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Battogtokh D, Tyson JJ. Nucleation of stem cell domains in a bistable activator-inhibitor model of the shoot apical meristem. CHAOS (WOODBURY, N.Y.) 2022; 32:093117. [PMID: 36182391 DOI: 10.1063/5.0093841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/03/2022] [Indexed: 06/16/2023]
Abstract
Shoot apical meristems (SAMs) give rise to all above-ground tissues of a plant. Expansion of meristematic tissue is derived from the growth and division of stem cells that reside in a central zone of the SAM. This reservoir of stem cells is maintained by expression of a transcription factor WUSCHEL that is responsible for the development of stem cells in the central zone. WUSCHEL expression is self-activating and downregulated by a signaling pathway initiated by CLAVATA proteins, which are upregulated by WUSCHEL. This classic activator-inhibitor network can generate localized patterns of WUSCHEL activity by a Turing instability provided certain constraints on reaction rates and diffusion constants of WUSCHEL and CLAVATA are satisfied, and most existing mathematical models of nucleation and confinement of stem cells in the SAM rely on Turing's mechanism. However, Turing patterns have certain properties that are inconsistent with observed patterns of stem cell differentiation in the SAM. As an alternative mechanism, we propose a model for stem cell confinement based on a bistable-switch in WUSCHEL-CLAVATA interactions. We study the bistable-switch mechanism for pattern formation in a spatially continuous domain and in a discrete cellularized tissue in the presence of a non-uniform field of a rapidly diffusing hormone. By comparing domain formation by Turing and bistable-switch mechanisms in these contexts, we show that bistable switching provides a superior account of nucleation and confinement of the stem cell domain under reasonable assumptions on reaction rates and diffusion constants.
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Affiliation(s)
- Dorjsuren Battogtokh
- Department of Biological Sciences, Virginia Polytechnic Institute & State University, Blacksburg, Virginia 24061, USA
| | - John J Tyson
- Department of Biological Sciences, Virginia Polytechnic Institute & State University, Blacksburg, Virginia 24061, USA
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Tyson JJ, Csikasz-Nagy A, Gonze D, Kim JK, Santos S, Wolf J. Time-keeping and decision-making in living cells: Part II. Interface Focus 2022. [PMCID: PMC9184961 DOI: 10.1098/rsfs.2022.0024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- John J. Tyson
- Department of Biological Sciences, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, USA
| | - Attila Csikasz-Nagy
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, 1088 Budapest, Hungary
| | - Didier Gonze
- Unit of Theoretical Chronobiology, Université Libre de Bruxelles, 1050 Brussels, Belgium
| | - Jae Kyoung Kim
- Department of Mathematical Sciences, KAIST, Daejeon 34141, South Korea
- Biomedical Mathematics Group, Institute for Basic Science, Daejeon 34126, South Korea
| | - Silvia Santos
- Quantitative Stem Cell Biology Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Jana Wolf
- Mathematical Modeling of Cellular Processes, Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany
- Department of Mathematics and Computer Science, Free University, 14195 Berlin, Germany
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7
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Xu H, Giannetti A, Sugiyama Y, Zheng W, Schneider R, Watanabe Y, Oda Y, Persson S. Secondary cell wall patterning-connecting the dots, pits and helices. Open Biol 2022; 12:210208. [PMID: 35506204 PMCID: PMC9065968 DOI: 10.1098/rsob.210208] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 04/07/2022] [Indexed: 01/04/2023] Open
Abstract
All plant cells are encased in primary cell walls that determine plant morphology, but also protect the cells against the environment. Certain cells also produce a secondary wall that supports mechanically demanding processes, such as maintaining plant body stature and water transport inside plants. Both these walls are primarily composed of polysaccharides that are arranged in certain patterns to support cell functions. A key requisite for patterned cell walls is the arrangement of cortical microtubules that may direct the delivery of wall polymers and/or cell wall producing enzymes to certain plasma membrane locations. Microtubules also steer the synthesis of cellulose-the load-bearing structure in cell walls-at the plasma membrane. The organization and behaviour of the microtubule array are thus of fundamental importance to cell wall patterns. These aspects are controlled by the coordinated effort of small GTPases that probably coordinate a Turing's reaction-diffusion mechanism to drive microtubule patterns. Here, we give an overview on how wall patterns form in the water-transporting xylem vessels of plants. We discuss systems that have been used to dissect mechanisms that underpin the xylem wall patterns, emphasizing the VND6 and VND7 inducible systems, and outline challenges that lay ahead in this field.
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Affiliation(s)
- Huizhen Xu
- School of Biosciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Alessandro Giannetti
- Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
| | - Yuki Sugiyama
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK
| | - Wenna Zheng
- School of Biosciences, The University of Melbourne, Parkville, Victoria 3010, Australia
- Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
| | - René Schneider
- Institute of Biochemistry and Biology, Plant Physiology Department, University of Potsdam, 14476 Potsdam, Germany
| | - Yoichiro Watanabe
- Institute for Research Initiatives, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Yoshihisa Oda
- Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, The Graduate University for Advanced Studies, SOKENDAI, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Staffan Persson
- School of Biosciences, The University of Melbourne, Parkville, Victoria 3010, Australia
- Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
- Copenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
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8
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Yin X. Phyllotaxis: from classical knowledge to molecular genetics. JOURNAL OF PLANT RESEARCH 2021; 134:373-401. [PMID: 33550488 DOI: 10.1007/s10265-020-01247-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 12/18/2020] [Indexed: 06/12/2023]
Abstract
Plant organs are repetitively generated at the shoot apical meristem (SAM) in recognizable patterns. This phenomenon, known as phyllotaxis, has long fascinated scientists from different disciplines. While we have an enriched body of knowledge on phyllotactic patterns, parameters, and transitions, only in the past 20 years, however, have we started to identify genes and elucidate genetic pathways that involved in phyllotaxis. In this review, I first summarize the classical knowledge of phyllotaxis from a morphological perspective. I then discuss recent advances in the regulation of phyllotaxis, from a molecular genetics perspective. I show that the morphological beauty of phyllotaxis we appreciate is the manifestation of many regulators, in addition to the critical role of auxin as a patterning signal, exerting their respective effects in a coordinated fashion either directly or indirectly in the SAM.
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Affiliation(s)
- Xiaofeng Yin
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033, Japan.
- Japan Society for the Promotion of Science, Tokyo, Japan.
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9
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Kataoka K, Fujita H, Isa M, Gotoh S, Arasaki A, Ishida H, Kimura R. The human EDAR 370V/A polymorphism affects tooth root morphology potentially through the modification of a reaction-diffusion system. Sci Rep 2021; 11:5143. [PMID: 33664401 PMCID: PMC7933414 DOI: 10.1038/s41598-021-84653-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 02/15/2021] [Indexed: 01/31/2023] Open
Abstract
Morphological variations in human teeth have long been recognized and, in particular, the spatial and temporal distribution of two patterns of dental features in Asia, i.e., Sinodonty and Sundadonty, have contributed to our understanding of the human migration history. However, the molecular mechanisms underlying such dental variations have not yet been completely elucidated. Recent studies have clarified that a nonsynonymous variant in the ectodysplasin A receptor gene (EDAR 370V/A; rs3827760) contributes to crown traits related to Sinodonty. In this study, we examined the association between the EDAR polymorphism and tooth root traits by using computed tomography images and identified that the effects of the EDAR variant on the number and shape of roots differed depending on the tooth type. In addition, to better understand tooth root morphogenesis, a computational analysis for patterns of tooth roots was performed, assuming a reaction-diffusion system. The computational study suggested that the complicated effects of the EDAR polymorphism could be explained when it is considered that EDAR modifies the syntheses of multiple related molecules working in the reaction-diffusion dynamics. In this study, we shed light on the molecular mechanisms of tooth root morphogenesis, which are less understood in comparison to those of tooth crown morphogenesis.
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Affiliation(s)
- Keiichi Kataoka
- Department of Human Biology and Anatomy, Graduate School of Medicine, University of the Ryukyus, Okinawa, 903-0215, Japan
- Department of Oral and Maxillofacial Functional Rehabilitation, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Hironori Fujita
- Astrobiology Center, National Institutes of Natural Sciences, Tokyo, Japan
- National Institute for Basic Biology, National Institutes of Natural Sciences, Aichi, Japan
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate School for Advanced Studies), Aichi, Japan
| | - Mutsumi Isa
- Department of Human Biology and Anatomy, Graduate School of Medicine, University of the Ryukyus, Okinawa, 903-0215, Japan
| | - Shimpei Gotoh
- Department of Human Biology and Anatomy, Graduate School of Medicine, University of the Ryukyus, Okinawa, 903-0215, Japan
- Department of Oral and Maxillofacial Functional Rehabilitation, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Akira Arasaki
- Department of Oral and Maxillofacial Functional Rehabilitation, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Hajime Ishida
- Department of Human Biology and Anatomy, Graduate School of Medicine, University of the Ryukyus, Okinawa, 903-0215, Japan
| | - Ryosuke Kimura
- Department of Human Biology and Anatomy, Graduate School of Medicine, University of the Ryukyus, Okinawa, 903-0215, Japan.
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10
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McGuire MK, Fuller CA, Lindner JF, Manz N. Geographic tongue as a reaction-diffusion system. CHAOS (WOODBURY, N.Y.) 2021; 31:033118. [PMID: 33810753 DOI: 10.1063/5.0020906] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 11/04/2020] [Indexed: 06/12/2023]
Abstract
Geographic tongue or benign migratory glossitis is a condition of an unknown cause characterized by chronic lesions that slowly migrate across the surface of the tongue. The condition's characteristic wavefronts suggest that it can be modeled as a reaction-diffusion system. Here, we present a model for geographic tongue pattern evolution using reaction-diffusion equations applied to portions of spheroids and paraboloids that approximate a tongue shape. We demonstrate that the observed patterns of geographic tongue lesions can be explained by propagating reaction-diffusion waves on these variably curved surfaces.
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Affiliation(s)
| | - Chase A Fuller
- Department of Physics, The College of Wooster, Wooster, Ohio 44691, USA
| | - John F Lindner
- Department of Physics, The College of Wooster, Wooster, Ohio 44691, USA
| | - Niklas Manz
- Department of Physics, The College of Wooster, Wooster, Ohio 44691, USA
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11
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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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12
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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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13
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Fouracre JP, Poethig RS. Role for the shoot apical meristem in the specification of juvenile leaf identity in Arabidopsis. Proc Natl Acad Sci U S A 2019; 116:10168-10177. [PMID: 31023887 PMCID: PMC6525512 DOI: 10.1073/pnas.1817853116] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The extent to which the shoot apical meristem (SAM) controls developmental decisions, rather than interpreting them, is a longstanding issue in plant development. Previous work suggests that vegetative phase change is regulated by signals intrinsic and extrinsic to the SAM, but the relative importance of these signals for this process is unknown. We investigated this question by examining the effect of meristem-deficient mutations on vegetative phase change and on the expression of key regulators of this process, miR156 and its targets, SPL transcription factors. We found that the precocious phenotypes of meristem-deficient mutants are a consequence of reduced miR156 accumulation. Tissue-specific manipulation of miR156 levels revealed that the SAM functions as an essential pool of miR156 early in shoot development, but that its effect on leaf identity declines with age. We also found that SPL genes control meristem size by repressing WUSCHEL expression via a novel genetic pathway.
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Affiliation(s)
- Jim P Fouracre
- Biology Department, University of Pennsylvania, Philadelphia, PA 19104
| | - R Scott Poethig
- Biology Department, University of Pennsylvania, Philadelphia, PA 19104
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14
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Nakamasu A, Higaki T. Theoretical models for branch formation in plants. JOURNAL OF PLANT RESEARCH 2019; 132:325-333. [PMID: 31004242 PMCID: PMC7082385 DOI: 10.1007/s10265-019-01107-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023]
Abstract
Various branch architectures are observed in living organisms including plants. Branch formation has traditionally been an area of interest in the field of developmental biology, and theoretical approaches are now commonly used to understand the complex mechanisms involved. In this review article, we provide an overview of theoretical approaches including mathematical models and computer simulations for studying plant branch formation. These approaches cover a wide range of topics. In particular, we focus on the importance of positional information in branch formation, which has been especially revealed by theoretical research in plants including computations of developmental processes.
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Affiliation(s)
- Akiko Nakamasu
- International Research Organization for Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuou-ku, Kumamoto, 860-8555, Japan.
| | - Takumi Higaki
- International Research Organization for Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuou-ku, Kumamoto, 860-8555, Japan.
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15
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A Rho-based reaction-diffusion system governs cell wall patterning in metaxylem vessels. Sci Rep 2018; 8:11542. [PMID: 30069009 PMCID: PMC6070580 DOI: 10.1038/s41598-018-29543-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 07/12/2018] [Indexed: 12/21/2022] Open
Abstract
Rho GTPases play crucial roles in cell polarity and pattern formation. ROPs, Rho of plant GTPases, are widely involved in cell wall patterning in plants, yet the molecular mechanism underlying their action remains unknown. Arabidopsis ROP11 is locally activated to form plasma membrane domains, which direct formation of cell wall pits in metaxylem vessel cells through interaction with cortical microtubules. Here, we show that the pattern formation of cell wall pits is governed by ROP activation via a reaction-diffusion mechanism. Genetic analysis and reconstructive assays revealed that ROPGEF4/7 and ROPGAP3/4, which encode ROP activators and inactivators, respectively, regulated the formation of ROP-activated domains; these in turn determined the pattern of cell wall pits. Mathematical modelling showed that ROP-activation cycle generated ROP domains by reaction-diffusion mechanism. The model predicted that a positive feedback and slow diffusion of ROP11-ROPGEF4 complex were required to generate ROP-activated domains. ROPGEF4 formed a dimer that interacted with activated ROP11 in vivo, which could provide positive feedback for ROP activation. ROPGEF4 was highly stable on the plasma membrane and inhibited ROP11 diffusion. Our study indicated that ROP-based reaction-diffusion system self-organizes ROP-activated domains, thereby determines the pit pattern of metaxylem vessels.
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16
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Hashimoto A, Nagao A, Okuda S. Topological graph description of multicellular dynamics based on vertex model. J Theor Biol 2018; 437:187-201. [PMID: 29080778 DOI: 10.1016/j.jtbi.2017.10.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 10/16/2017] [Accepted: 10/20/2017] [Indexed: 11/16/2022]
Abstract
Vertex models are generally powerful tools for exploring biological insights into multicellular dynamics. In these models, a multicellular structure is represented by a network, which is dynamically rearranged using topological operations. Remarkably, the topological dynamics of the network are important in guaranteeing the results from the models and their biological implications. However, it remains unclear whether the entire pattern of multicellular topological dynamics can be accurately expressed by a set of operators in the models. Surprisingly, vertex models have been empirically used for several decades without any mathematical verification. In this study, we propose a rigorous two-/three-dimensional (2D/3D) vertex model to describe multicellular topological dynamics. To do this, we classify several types of vertex models from a graph-theoretic perspective. Based on the classification, mathematical analyses reveal several conditions that enable us to apply the operators accurately without topological errors. Under these conditions, the operators can completely express the entire pattern of multicellular topological dynamics. From these results, we newly propose rigorous 2D/3D vertex models that can be applied to general multicellular dynamics, and we clarify several points to verify the results obtained from previous models.
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Affiliation(s)
- Atsushi Hashimoto
- Graduate School of Education, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Atsuki Nagao
- Graduate School of Informatics and Engineering, University of Electro-Communication, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan
| | - Satoru Okuda
- RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
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17
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Snipes SA, Rodriguez K, DeVries AE, Miyawaki KN, Perales M, Xie M, Reddy GV. Cytokinin stabilizes WUSCHEL by acting on the protein domains required for nuclear enrichment and transcription. PLoS Genet 2018; 14:e1007351. [PMID: 29659567 PMCID: PMC5919686 DOI: 10.1371/journal.pgen.1007351] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 04/26/2018] [Accepted: 04/03/2018] [Indexed: 11/18/2022] Open
Abstract
Concentration-dependent transcriptional regulation and the spatial regulation of transcription factor levels are poorly studied in plant development. WUSCHEL, a stem cell-promoting homeodomain transcription factor, accumulates at a higher level in the rib meristem than in the overlying central zone, which harbors stem cells in the shoot apical meristems of Arabidopsis thaliana. The differential accumulation of WUSCHEL in adjacent cells is critical for the spatial regulation and levels of CLAVATA3, a negative regulator of WUSCHEL transcription. Earlier studies have revealed that DNA-dependent dimerization, subcellular partitioning and protein destabilization control WUSCHEL protein levels and spatial accumulation. Moreover, the destabilization of WUSCHEL may also depend on the protein concentration. However, the roles of extrinsic spatial cues in maintaining differential accumulation of WUS are not understood. Through transient manipulation of hormone levels, hormone response patterns and analysis of the receptor mutants, we show that cytokinin signaling in the rib meristem acts through the transcriptional regulatory domains, the acidic domain and the WUSCHEL-box, to stabilize the WUS protein. Furthermore, we show that the same WUSCHEL-box functions as a degron sequence in cytokinin deficient regions in the central zone, leading to the destabilization of WUSCHEL. The coupled functions of the WUSCHEL-box in nuclear retention as described earlier, together with cytokinin sensing, reinforce higher nuclear accumulation of WUSCHEL in the rib meristem. In contrast a sub-threshold level may expose the WUSCHEL-box to destabilizing signals in the central zone. Thus, the cytokinin signaling acts as an asymmetric spatial cue in stabilizing the WUSCHEL protein to lead to its differential accumulation in neighboring cells, which is critical for concentration-dependent spatial regulation of CLAVATA3 transcription and meristem maintenance. Furthermore, our work shows that cytokinin response is regulated independently of the WUSCHEL function which may provide robustness to the regulation of WUSCHEL concentration. Stem cell regulation is critical for the development of all organisms, and plants have particularly unique stem cell populations that are maintained throughout their lifespan at the tips of both the shoots and roots. Proper spatial and temporal regulation of gene expression by mobile proteins is essential for maintaining these stem cell populations. Here we show that in the shoot, the mobile stem cell promoting factor WUSCHEL is stabilized at the protein level by the plant hormone cytokinin. This stabilization occurs in a tightly restricted spatial context, and movement of WUSCHEL outside of this region results in WUSCHEL instability that leads to its degradation. The specific regions on the WUSCHEL protein that respond to the cytokinin signaling are the same regions that are essential for both proper WUSCHEL localization in the nucleus and regulation of its target genes. This spatially specific response to cytokinin results in differential accumulation of WUSCHEL in space, and reveals an intrinsic link between protein stability and the regulation of target genes to maintain a stable population of stem cells.
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Affiliation(s)
- Stephen A. Snipes
- Department of Botany and Plant Sciences, Center for Plant Cell Biology (CEPCEB), Institute of Integrative Genome Biology (IIGB), University of California, Riverside, California, United States of America
| | - Kevin Rodriguez
- Department of Botany and Plant Sciences, Center for Plant Cell Biology (CEPCEB), Institute of Integrative Genome Biology (IIGB), University of California, Riverside, California, United States of America
| | - Aaron E. DeVries
- Department of Botany and Plant Sciences, Center for Plant Cell Biology (CEPCEB), Institute of Integrative Genome Biology (IIGB), University of California, Riverside, California, United States of America
| | - Kaori N. Miyawaki
- Department of Botany and Plant Sciences, Center for Plant Cell Biology (CEPCEB), Institute of Integrative Genome Biology (IIGB), University of California, Riverside, California, United States of America
| | - Mariano Perales
- Department of Botany and Plant Sciences, Center for Plant Cell Biology (CEPCEB), Institute of Integrative Genome Biology (IIGB), University of California, Riverside, California, United States of America
| | - Mingtang Xie
- Department of Botany and Plant Sciences, Center for Plant Cell Biology (CEPCEB), Institute of Integrative Genome Biology (IIGB), University of California, Riverside, California, United States of America
| | - G. Venugopala Reddy
- Department of Botany and Plant Sciences, Center for Plant Cell Biology (CEPCEB), Institute of Integrative Genome Biology (IIGB), University of California, Riverside, California, United States of America
- * E-mail:
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18
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Holloway DM, Rozada I, Bray JJH. Two-stage patterning dynamics in conifer cotyledon whorl morphogenesis. ANNALS OF BOTANY 2018; 121:525-534. [PMID: 29309524 PMCID: PMC5838814 DOI: 10.1093/aob/mcx185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 09/16/2017] [Indexed: 06/03/2023]
Abstract
Background and Aims Conifer embryos, unlike those of monocots or dicots, have variable numbers of cotyledons, even within the same species. Cotyledons form in a single whorl on a dome-shaped embryo. The closely spaced cotyledons are not found outside this ring, indicating a radial control on where they can form. Polar transport of the hormone auxin affects outgrowth of distinct cotyledons, but not the radial aspect of the whorl or the within-whorl spacing between cotyledons. A quantitative model of plant growth regulator patterning is needed to understand the dynamics of this complex morphogenetic process. Methods A two-stage reaction-diffusion model is developed for the spatial patterning of growth regulators on the embryo surface, with a radial pattern (P1) constraining the shorter-wavelength cotyledon pattern (P2) to a whorl. These patterns drive three-dimensional (3-D) morphogenesis by catalysing local surface growth. Key Results Growth driven by P2 generates single whorls across the experimentally observed range of two to 11 cotyledons, as well as the circularly symmetric response to auxin transport interference. These computations are the first corroboration of earlier theoretical proposals for hierarchical control of whorl formation. The model generates the linear relationship between cotyledon number and embryo diameter observed experimentally. This accounts for normal integer cotyledon number selection, as well as the less common cotyledon fusings and splittings observed experimentally. Flattening of the embryo during development may affect the upward outgrowth angle of the cotyledons. Conclusions Cotyledon morphogenesis is more complex geometrically in conifers than in angiosperms, involving 2-D patterning which deforms a surface in three dimensions. This work develops a quantitative framework for understanding the growth and patterning dynamics involved in conifer cotyledon development, and applies more generally to the morphogenesis of whorls with many primordia.
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Affiliation(s)
- David M Holloway
- Mathematics Department, British Columbia Institute of Technology, Burnaby, B.C., Canada
- Biology Department, University of Victoria, Victoria, B.C., Canada
| | - Ignacio Rozada
- Mathematics Department, British Columbia Institute of Technology, Burnaby, B.C., Canada
| | - Joshua J H Bray
- Biotechnology Program, British Columbia Institute of Technology, Burnaby, B.C., Canada
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19
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Okuda S, Miura T, Inoue Y, Adachi T, Eiraku M. Combining Turing and 3D vertex models reproduces autonomous multicellular morphogenesis with undulation, tubulation, and branching. Sci Rep 2018; 8:2386. [PMID: 29402913 PMCID: PMC5799218 DOI: 10.1038/s41598-018-20678-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 01/19/2018] [Indexed: 01/13/2023] Open
Abstract
This study demonstrates computational simulations of multicellular deformation coupled with chemical patterning in the three-dimensional (3D) space. To address these aspects, we proposes a novel mathematical model, where a reaction–diffusion system is discretely expressed at a single cell level and combined with a 3D vertex model. To investigate complex phenomena emerging from the coupling of patterning and deformation, as an example, we employed an activator–inhibitor system and converted the activator concentration of individual cells into their growth rate. Despite the simplicity of the model, by growing a monolayer cell vesicle, the coupling system provided rich morphological dynamics such as undulation, tubulation, and branching. Interestingly, the morphological variety depends on the difference in time scales between patterning and deformation, and can be partially understood by the intrinsic hysteresis in the activator-inhibitor system with domain growth. Importantly, the model can be applied to 3D multicellular dynamics that couple the reaction–diffusion patterning with various cell behaviors, such as deformation, rearrangement, division, apoptosis, differentiation, and proliferation. Thus, the results demonstrate the significant advantage of the proposed model as well as the biophysical importance of exploring spatiotemporal dynamics of the coupling phenomena of patterning and deformation in 3D space.
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Affiliation(s)
- Satoru Okuda
- RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo, 650-0047, Japan. .,PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
| | - Takashi Miura
- Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Yasuhiro Inoue
- Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Taiji Adachi
- Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Mototsugu Eiraku
- RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo, 650-0047, Japan.,Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
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20
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Truskina J, Vernoux T. The growth of a stable stationary structure: coordinating cell behavior and patterning at the shoot apical meristem. CURRENT OPINION IN PLANT BIOLOGY 2018; 41:83-88. [PMID: 29073502 DOI: 10.1016/j.pbi.2017.09.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 09/27/2017] [Accepted: 09/27/2017] [Indexed: 05/23/2023]
Abstract
Plants are characterized by their ability to produce new organs post-embryonically throughout their entire life cycle. In particular development of all above-ground organs relies almost entirely on the function of the shoot apical meristem (SAM). The SAM performs a dual role by maintaining a pool of undifferentiated cells and simultaneously driving cell differentiation to initiate organogenesis. Both processes require strict coordination between individual cells which leads to formation of reproducible morphological and molecular patterns within SAM. The patterns are formed and maintained in large part due to spatio-temporal variation in signaling of plant hormones auxin and cytokinin resulting in tissue-specific transcriptional regulation. Integration of these mechanisms into computational models further identifies the key regulatory interactions involved in SAM function.
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Affiliation(s)
- Jekaterina Truskina
- Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342 Lyon, France; Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - Teva Vernoux
- Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342 Lyon, France.
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21
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Bucksch A, Atta-Boateng A, Azihou AF, Battogtokh D, Baumgartner A, Binder BM, Braybrook SA, Chang C, Coneva V, DeWitt TJ, Fletcher AG, Gehan MA, Diaz-Martinez DH, Hong L, Iyer-Pascuzzi AS, Klein LL, Leiboff S, Li M, Lynch JP, Maizel A, Maloof JN, Markelz RJC, Martinez CC, Miller LA, Mio W, Palubicki W, Poorter H, Pradal C, Price CA, Puttonen E, Reese JB, Rellán-Álvarez R, Spalding EP, Sparks EE, Topp CN, Williams JH, Chitwood DH. Morphological Plant Modeling: Unleashing Geometric and Topological Potential within the Plant Sciences. FRONTIERS IN PLANT SCIENCE 2017; 8:900. [PMID: 28659934 PMCID: PMC5465304 DOI: 10.3389/fpls.2017.00900] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 05/12/2017] [Indexed: 05/21/2023]
Abstract
The geometries and topologies of leaves, flowers, roots, shoots, and their arrangements have fascinated plant biologists and mathematicians alike. As such, plant morphology is inherently mathematical in that it describes plant form and architecture with geometrical and topological techniques. Gaining an understanding of how to modify plant morphology, through molecular biology and breeding, aided by a mathematical perspective, is critical to improving agriculture, and the monitoring of ecosystems is vital to modeling a future with fewer natural resources. In this white paper, we begin with an overview in quantifying the form of plants and mathematical models of patterning in plants. We then explore the fundamental challenges that remain unanswered concerning plant morphology, from the barriers preventing the prediction of phenotype from genotype to modeling the movement of leaves in air streams. We end with a discussion concerning the education of plant morphology synthesizing biological and mathematical approaches and ways to facilitate research advances through outreach, cross-disciplinary training, and open science. Unleashing the potential of geometric and topological approaches in the plant sciences promises to transform our understanding of both plants and mathematics.
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Affiliation(s)
- Alexander Bucksch
- Department of Plant Biology, University of Georgia, AthensGA, United States
- Warnell School of Forestry and Natural Resources, University of Georgia, AthensGA, United States
- Institute of Bioinformatics, University of Georgia, AthensGA, United States
| | | | - Akomian F. Azihou
- Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-CalaviCotonou, Benin
| | - Dorjsuren Battogtokh
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, BlacksburgVA, United States
| | - Aly Baumgartner
- Department of Geosciences, Baylor University, WacoTX, United States
| | - Brad M. Binder
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, KnoxvilleTN, United States
| | | | - Cynthia Chang
- Division of Biology, University of Washington, BothellWA, United States
| | - Viktoirya Coneva
- Donald Danforth Plant Science Center, St. LouisMO, United States
| | - Thomas J. DeWitt
- Department of Wildlife and Fisheries Sciences–Department of Plant Pathology and Microbiology, Texas A&M University, College StationTX, United States
| | - Alexander G. Fletcher
- School of Mathematics and Statistics and Bateson Centre, University of SheffieldSheffield, United Kingdom
| | - Malia A. Gehan
- Donald Danforth Plant Science Center, St. LouisMO, United States
| | | | - Lilan Hong
- Weill Institute for Cell and Molecular Biology and Section of Plant Biology, School of Integrative Plant Sciences, Cornell University, IthacaNY, United States
| | - Anjali S. Iyer-Pascuzzi
- Department of Botany and Plant Pathology, Purdue University, West LafayetteIN, United States
| | - Laura L. Klein
- Department of Biology, Saint Louis University, St. LouisMO, United States
| | - Samuel Leiboff
- School of Integrative Plant Science, Cornell University, IthacaNY, United States
| | - Mao Li
- Department of Mathematics, Florida State University, TallahasseeFL, United States
| | - Jonathan P. Lynch
- Department of Plant Science, The Pennsylvania State University, University ParkPA, United States
| | - Alexis Maizel
- Center for Organismal Studies, Heidelberg UniversityHeidelberg, Germany
| | - Julin N. Maloof
- Department of Plant Biology, University of California, Davis, DavisCA, United States
| | - R. J. Cody Markelz
- Department of Plant Biology, University of California, Davis, DavisCA, United States
| | - Ciera C. Martinez
- Department of Molecular and Cell Biology, University of California, Berkeley, BerkeleyCA, United States
| | - Laura A. Miller
- Program in Bioinformatics and Computational Biology, The University of North Carolina, Chapel HillNC, United States
| | - Washington Mio
- Department of Mathematics, Florida State University, TallahasseeFL, United States
| | - Wojtek Palubicki
- The Sainsbury Laboratory, University of CambridgeCambridge, United Kingdom
| | - Hendrik Poorter
- Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, JülichGermany
| | | | - Charles A. Price
- National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, KnoxvilleTN, United States
| | - Eetu Puttonen
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute, National Land Survey of FinlandMasala, Finland
- Centre of Excellence in Laser Scanning Research, National Land Survey of FinlandMasala, Finland
| | - John B. Reese
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, KnoxvilleTN, United States
| | - Rubén Rellán-Álvarez
- Unidad de Genómica Avanzada, Laboratorio Nacional de Genómica para la Biodiversidad, Center for Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV)Irapuato, Mexico
| | - Edgar P. Spalding
- Department of Botany, University of Wisconsin–Madison, MadisonWI, United States
| | - Erin E. Sparks
- Department of Plant and Soil Sciences and Delaware Biotechnology Institute, University of Delaware, NewarkDE, United States
| | | | - Joseph H. Williams
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, KnoxvilleTN, United States
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22
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Yin X, Meicenheimer RD. Anisotomous dichotomy results from an unequal bifurcation of the original shoot apical meristem in Diphasiastrum digitatum (Lycopodiaceae). AMERICAN JOURNAL OF BOTANY 2017; 104:782-786. [PMID: 28526723 DOI: 10.3732/ajb.1700021] [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: 01/17/2017] [Accepted: 04/18/2017] [Indexed: 06/07/2023]
Abstract
PREMISE OF THE STUDY Two types of dichotomy are recognized in Lycopodiaceae: isotomous (equal) and anisotomous (unequal). Anisotomous dichotomy (anisotomy) has been hypothesized to result from unequal growth of an equal bifurcation of the original shoot apical meristem (SAM). Diphasiastrum digitatum (Lycopodiaceae) exhibits anisotomy at various locations. We thus used D. digitatum to test this classic hypothesis about anisotomy. METHODS Transverse areas of original and derived SAMs of anisotomy exhibited by the rhizome and the vertical aerial vegetative stem were measured using scanning electron microscopy. The difference between half of the original SAM and one derived SAM in terms of transverse area were compared using paired t-tests. KEY RESULTS During the anisotomy exhibited by the rhizome SAM, 77.4% of the transverse area of the original rhizome SAM contributed to the derived rhizome SAM. During the first anisotomy exhibited by the vertical aerial vegetative stem SAM, 66.2% of the transverse area of the original vertical aerial vegetative stem SAM contributed to the derived vertical aerial vegetative stem SAM. During the second anisotomy exhibited by the vertical aerial vegetative stem SAM, 49.4% of the transverse area of the original vertical aerial vegetative stem SAM contributed to the derived vertical aerial vegetative stem SAM. Nonetheless, the shape of the two derived SAMs differed though they did not differ in size. CONCLUSIONS In D. digitatum, anisotomy results from an unequal bifurcation of the original SAM. This finding sheds light on plant body architecture evolution as well as plant organ (megaphyllous leaf) evolution.
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Affiliation(s)
- Xiaofeng Yin
- Department of Botany, Miami University, 316 Pearson Hall, Oxford, Ohio 45056 USA
| | - Roger D Meicenheimer
- Department of Botany, Miami University, 316 Pearson Hall, Oxford, Ohio 45056 USA
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23
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Bucksch A, Atta-Boateng A, Azihou AF, Battogtokh D, Baumgartner A, Binder BM, Braybrook SA, Chang C, Coneva V, DeWitt TJ, Fletcher AG, Gehan MA, Diaz-Martinez DH, Hong L, Iyer-Pascuzzi AS, Klein LL, Leiboff S, Li M, Lynch JP, Maizel A, Maloof JN, Markelz RJC, Martinez CC, Miller LA, Mio W, Palubicki W, Poorter H, Pradal C, Price CA, Puttonen E, Reese JB, Rellán-Álvarez R, Spalding EP, Sparks EE, Topp CN, Williams JH, Chitwood DH. Morphological Plant Modeling: Unleashing Geometric and Topological Potential within the Plant Sciences. FRONTIERS IN PLANT SCIENCE 2017. [PMID: 28659934 DOI: 10.3389/978-2-88945-297-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The geometries and topologies of leaves, flowers, roots, shoots, and their arrangements have fascinated plant biologists and mathematicians alike. As such, plant morphology is inherently mathematical in that it describes plant form and architecture with geometrical and topological techniques. Gaining an understanding of how to modify plant morphology, through molecular biology and breeding, aided by a mathematical perspective, is critical to improving agriculture, and the monitoring of ecosystems is vital to modeling a future with fewer natural resources. In this white paper, we begin with an overview in quantifying the form of plants and mathematical models of patterning in plants. We then explore the fundamental challenges that remain unanswered concerning plant morphology, from the barriers preventing the prediction of phenotype from genotype to modeling the movement of leaves in air streams. We end with a discussion concerning the education of plant morphology synthesizing biological and mathematical approaches and ways to facilitate research advances through outreach, cross-disciplinary training, and open science. Unleashing the potential of geometric and topological approaches in the plant sciences promises to transform our understanding of both plants and mathematics.
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Affiliation(s)
- Alexander Bucksch
- Department of Plant Biology, University of Georgia, AthensGA, United States
- Warnell School of Forestry and Natural Resources, University of Georgia, AthensGA, United States
- Institute of Bioinformatics, University of Georgia, AthensGA, United States
| | | | - Akomian F Azihou
- Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-CalaviCotonou, Benin
| | - Dorjsuren Battogtokh
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, BlacksburgVA, United States
| | - Aly Baumgartner
- Department of Geosciences, Baylor University, WacoTX, United States
| | - Brad M Binder
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, KnoxvilleTN, United States
| | | | - Cynthia Chang
- Division of Biology, University of Washington, BothellWA, United States
| | - Viktoirya Coneva
- Donald Danforth Plant Science Center, St. LouisMO, United States
| | - Thomas J DeWitt
- Department of Wildlife and Fisheries Sciences-Department of Plant Pathology and Microbiology, Texas A&M University, College StationTX, United States
| | - Alexander G Fletcher
- School of Mathematics and Statistics and Bateson Centre, University of SheffieldSheffield, United Kingdom
| | - Malia A Gehan
- Donald Danforth Plant Science Center, St. LouisMO, United States
| | | | - Lilan Hong
- Weill Institute for Cell and Molecular Biology and Section of Plant Biology, School of Integrative Plant Sciences, Cornell University, IthacaNY, United States
| | - Anjali S Iyer-Pascuzzi
- Department of Botany and Plant Pathology, Purdue University, West LafayetteIN, United States
| | - Laura L Klein
- Department of Biology, Saint Louis University, St. LouisMO, United States
| | - Samuel Leiboff
- School of Integrative Plant Science, Cornell University, IthacaNY, United States
| | - Mao Li
- Department of Mathematics, Florida State University, TallahasseeFL, United States
| | - Jonathan P Lynch
- Department of Plant Science, The Pennsylvania State University, University ParkPA, United States
| | - Alexis Maizel
- Center for Organismal Studies, Heidelberg UniversityHeidelberg, Germany
| | - Julin N Maloof
- Department of Plant Biology, University of California, Davis, DavisCA, United States
| | - R J Cody Markelz
- Department of Plant Biology, University of California, Davis, DavisCA, United States
| | - Ciera C Martinez
- Department of Molecular and Cell Biology, University of California, Berkeley, BerkeleyCA, United States
| | - Laura A Miller
- Program in Bioinformatics and Computational Biology, The University of North Carolina, Chapel HillNC, United States
| | - Washington Mio
- Department of Mathematics, Florida State University, TallahasseeFL, United States
| | - Wojtek Palubicki
- The Sainsbury Laboratory, University of CambridgeCambridge, United Kingdom
| | - Hendrik Poorter
- Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, JülichGermany
| | | | - Charles A Price
- National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, KnoxvilleTN, United States
| | - Eetu Puttonen
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute, National Land Survey of FinlandMasala, Finland
- Centre of Excellence in Laser Scanning Research, National Land Survey of FinlandMasala, Finland
| | - John B Reese
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, KnoxvilleTN, United States
| | - Rubén Rellán-Álvarez
- Unidad de Genómica Avanzada, Laboratorio Nacional de Genómica para la Biodiversidad, Center for Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV)Irapuato, Mexico
| | - Edgar P Spalding
- Department of Botany, University of Wisconsin-Madison, MadisonWI, United States
| | - Erin E Sparks
- Department of Plant and Soil Sciences and Delaware Biotechnology Institute, University of Delaware, NewarkDE, United States
| | | | - Joseph H Williams
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, KnoxvilleTN, United States
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Morales-Tapia A, Cruz-Ramírez A. Computational Modeling of Auxin: A Foundation for Plant Engineering. FRONTIERS IN PLANT SCIENCE 2016; 7:1881. [PMID: 28066453 PMCID: PMC5168462 DOI: 10.3389/fpls.2016.01881] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 11/29/2016] [Indexed: 05/29/2023]
Abstract
Since the development of agriculture, humans have relied on the cultivation of plants to satisfy our increasing demand for food, natural products, and other raw materials. As we understand more about plant development, we can better manipulate plants to fulfill our particular needs. Auxins are a class of simple metabolites that coordinate many developmental activities like growth and the appearance of functional structures in plants. Computational modeling of auxin has proven to be an excellent tool in elucidating many mechanisms that underlie these developmental events. Due to the complexity of these mechanisms, current modeling efforts are concerned only with single phenomena focused on narrow spatial and developmental contexts; but a general model of plant development could be assembled by integrating the insights from all of them. In this perspective, we summarize the current collection of auxin-driven computational models, focusing on how they could come together into a single model for plant development. A model of this nature would allow researchers to test hypotheses in silico and yield accurate predictions about the behavior of a plant under a given set of physical and biochemical constraints. It would also provide a solid foundation toward the establishment of plant engineering, a proposed discipline intended to enable the design and production of plants that exhibit an arbitrarily defined set of features.
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Adibi M, Yoshida S, Weijers D, Fleck C. Centering the Organizing Center in the Arabidopsis thaliana Shoot Apical Meristem by a Combination of Cytokinin Signaling and Self-Organization. PLoS One 2016; 11:e0147830. [PMID: 26872130 PMCID: PMC4752473 DOI: 10.1371/journal.pone.0147830] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 01/08/2016] [Indexed: 12/15/2022] Open
Abstract
Plants have the ability to continously generate new organs by maintaining populations of stem cells throught their lives. The shoot apical meristem (SAM) provides a stable environment for the maintenance of stem cells. All cells inside the SAM divide, yet boundaries and patterns are maintained. Experimental evidence indicates that patterning is independent of cell lineage, thus a dynamic self-regulatory mechanism is required. A pivotal role in the organization of the SAM is played by the WUSCHEL gene (WUS). An important question in this regard is that how WUS expression is positioned in the SAM via a cell-lineage independent signaling mechanism. In this study we demonstrate via mathematical modeling that a combination of an inhibitor of the Cytokinin (CK) receptor, Arabidopsis histidine kinase 4 (AHK4) and two morphogens originating from the top cell layer, can plausibly account for the cell lineage-independent centering of WUS expression within SAM. Furthermore, our laser ablation and microsurgical experiments support the hypothesis that patterning in SAM occurs at the level of CK reception and signaling. The model suggests that the interplay between CK signaling, WUS/CLV feedback loop and boundary signals can account for positioning of the WUS expression, and provides directions for further experimental investigation.
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Affiliation(s)
- Milad Adibi
- Laboratory of Systems and Synthetic Biology, Wageningen University, Wageningen, the Netherlands
- * E-mail: (MA); (CF)
| | - Saiko Yoshida
- Laboratory of Biochemistry, Wageningen University, Wageningen, the Netherlands
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Wageningen, the Netherlands
| | - Christian Fleck
- Laboratory of Systems and Synthetic Biology, Wageningen University, Wageningen, the Netherlands
- * E-mail: (MA); (CF)
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Battogtokh D, Tyson JJ. A Bistable Switch Mechanism for Stem Cell Domain Nucleation in the Shoot Apical Meristem. FRONTIERS IN PLANT SCIENCE 2016; 7:674. [PMID: 27242874 PMCID: PMC4876614 DOI: 10.3389/fpls.2016.00674] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 05/02/2016] [Indexed: 05/22/2023]
Affiliation(s)
- Dorjsuren Battogtokh
- Department of Theoretical Physics, The Institute of Physics and Technology, Mongolian Academy of SciencesUlaanbaatar, Mongolia
- Department of Biological Sciences, Virginia Polytechnic and State UniversityBlacksburg, VA, USA
- *Correspondence: Dorjsuren Battogtokh
| | - John J. Tyson
- Department of Biological Sciences, Virginia Polytechnic and State UniversityBlacksburg, VA, USA
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Okuda S, Inoue Y, Watanabe T, Adachi T. Coupling intercellular molecular signalling with multicellular deformation for simulating three-dimensional tissue morphogenesis. Interface Focus 2015; 5:20140095. [PMID: 25844156 PMCID: PMC4342952 DOI: 10.1098/rsfs.2014.0095] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
During morphogenesis, three-dimensional (3D) multicellular structures emerge from biochemical and mechanical interplays among cells. In particular, by organizing their gradient within tissues, the diffusible signalling molecules play an essential role in producing the spatio-temporal patterns of cell status such as the differentiation states. Notably, this biochemical patterning can be dynamically coupled with multicellular deformations by signal-dependent cell activities such as contraction, adhesion, migration, proliferation and apoptosis. However, the mechanism by which these cellular activities mediate the interactions between multicellular deformations and patterning is still unknown. Herein, we propose a novel framework of a 3D vertex model to express molecular signalling among the mechanically deforming cells. By specifying a density of signalling molecules for each cell, we express their transport between neighbouring cells. By simulating signal-dependent epithelial growth, we found various types of tissue morphogenesis such as arrest, expansion, invagination and evagination. In the expansion phase, growth molecules were widely diffused with increasing tissue volume, which diluted the growth molecules in order to support the autonomous suppression of tissue growth. These results indicate that the proposed model successfully expresses 3D multicellular deformations dynamically coupled with biochemical patterning. We expect our proposed model to be a useful tool for predicting new phenomena emerging from mechanochemical coupling in multicellular morphogenesis.
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Affiliation(s)
- Satoru Okuda
- Organogenesis and Neurogenesis Group, Center for Developmental Biology, RIKEN, 2–2–3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650–0047, Japan
- Department of Biomechanics, Institute for Frontier Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606–8507, Japan
| | - Yasuhiro Inoue
- Department of Biomechanics, Institute for Frontier Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606–8507, Japan
| | - Tadashi Watanabe
- Department of Biomechanics, Institute for Frontier Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606–8507, Japan
| | - Taiji Adachi
- Department of Biomechanics, Institute for Frontier Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606–8507, Japan
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Battogtokh D. Domain nucleation and confinement in agent-controlled bistable systems. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:032713. [PMID: 25871150 DOI: 10.1103/physreve.91.032713] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Indexed: 05/13/2023]
Abstract
We report a mechanism of pattern formation in growing bistable systems coupled indirectly. A modified Fujita et al. model is studied as an example of a reaction-diffusion system of nondiffusive activator and inhibitor molecules immersed in the medium of a fast diffusive agent. Here we show that, as the system grows, a new domain nucleates spontaneously in the area where the local level of the agent becomes critical. Newly nucleated domains are stable and the pattern formation is different from Turing's mechanism in monostable systems. Domains are spatially confined by the agent even if the activator and inhibitor molecules diffuse. With the spatial extension of the system, a larger domain may undergo a wave number instability, and the concentrations of active molecules within the neighboring elements of a domain can become sharply different. The mechanism reported in this work could be generic for pattern formation systems involving multistability, growth, and indirect coupling.
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Affiliation(s)
- Dorjsuren Battogtokh
- The Institute of Physics and Technology, Mongolian Academy of Sciences, Ulaanbaatar 51, Mongolia and Department of Biological Sciences, Virginia Polytechnic and State University, Blacksburg, Virginia 24061, USA
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Cartenì F, Giannino F, Schweingruber FH, Mazzoleni S. Modelling the development and arrangement of the primary vascular structure in plants. ANNALS OF BOTANY 2014; 114:619-27. [PMID: 24799440 PMCID: PMC4156123 DOI: 10.1093/aob/mcu074] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS The process of vascular development in plants results in the formation of a specific array of bundles that run throughout the plant in a characteristic spatial arrangement. Although much is known about the genes involved in the specification of procambium, phloem and xylem, the dynamic processes and interactions that define the development of the radial arrangement of such tissues remain elusive. METHODS This study presents a spatially explicit reaction-diffusion model defining a set of logical and functional rules to simulate the differentiation of procambium, phloem and xylem and their spatial patterns, starting from a homogeneous group of undifferentiated cells. KEY RESULTS Simulation results showed that the model is capable of reproducing most vascular patterns observed in plants, from primitive and simple structures made up of a single strand of vascular bundles (protostele), to more complex and evolved structures, with separated vascular bundles arranged in an ordered pattern within the plant section (e.g. eustele). CONCLUSIONS The results presented demonstrate, as a proof of concept, that a common genetic-molecular machinery can be the basis of different spatial patterns of plant vascular development. Moreover, the model has the potential to become a useful tool to test different hypotheses of genetic and molecular interactions involved in the specification of vascular tissues.
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Affiliation(s)
- Fabrizio Cartenì
- Dipartimento di Agraria, University of Naples Federico II, via Università 100, 80055 Portici (Na), Italy
- For correspondence. E-mail
| | - Francesco Giannino
- Dipartimento di Agraria, University of Naples Federico II, via Università 100, 80055 Portici (Na), Italy
| | - Fritz Hans Schweingruber
- Swiss Federal Institut of Forest, Snow and Landscape Research WSL, CH- 8903 Birmensdorf, Switzerland
| | - Stefano Mazzoleni
- Dipartimento di Agraria, University of Naples Federico II, via Università 100, 80055 Portici (Na), Italy
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30
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Gola EM. Dichotomous branching: the plant form and integrity upon the apical meristem bifurcation. FRONTIERS IN PLANT SCIENCE 2014; 5:263. [PMID: 24936206 PMCID: PMC4047680 DOI: 10.3389/fpls.2014.00263] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 05/21/2014] [Indexed: 05/05/2023]
Abstract
The division of the apical meristem into two independently functioning axes is defined as dichotomous branching. This type of branching typically occurs in non-vascular and non-seed vascular plants, whereas in seed plants it presents a primary growth form only in several taxa. Dichotomy is a complex process, which requires a re-organization of the meristem structure and causes changes in the apex geometry and activity. However, the mechanisms governing the repetitive apex divisions are hardly known. Here, an overview of dichotomous branching is presented, occurring in structurally different apices of phylogenetically distant plants, and in various organs (e.g., shoots, roots, rhizophores). Additionally, morphogenetic effects of dichotomy are reviewed, including its impact on organogenesis and mechanical constraints. At the end, the hormonal and genetic regulation of the dichotomous branching is discussed.
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Affiliation(s)
- Edyta M. Gola
- Department of Plant Developmental Biology, Institute of Experimental Biology, University of WrocławWrocław, Poland
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31
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Benítez M, Hejátko J. Dynamics of cell-fate determination and patterning in the vascular bundles of Arabidopsis thaliana. PLoS One 2013; 8:e63108. [PMID: 23723973 PMCID: PMC3664626 DOI: 10.1371/journal.pone.0063108] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 03/28/2013] [Indexed: 12/22/2022] Open
Abstract
Plant vascular meristems are sets of pluripotent cells that enable radial growth by giving rise to vascular tissues and are therefore crucial to plant development. However, the overall dynamics of cellular determination and patterning in and around vascular meristems is still unexplored. We study this process in the shoot vascular tissue of Arabidopsis thaliana, which is organized in vascular bundles that contain three basic cell types (procambium, xylem and phloem). A set of molecules involved in this process has now been identified and partially characterized, but it is not yet clear how the regulatory interactions among them, in conjunction with cellular communication processes, give rise to the steady patterns that accompany cell-fate determination and arrangement within vascular bundles. We put forward a dynamic model factoring in the interactions between molecules (genes, peptides, mRNA and hormones) that have been reported to be central in this process, as well as the relevant communication mechanisms. When a few proposed interactions (unverified, but based on related data) are postulated, the model reproduces the hormonal and molecular patterns expected for the three regions within vascular bundles. In order to test the model, we simulated mutant and hormone-depleted systems and compared the results with experimentally reported phenotypes. The proposed model provides a formal framework integrating a set of growing experimental data and renders a dynamic account of how the collective action of hormones, genes, and other molecules may result in the specification of the three main cell types within shoot vascular bundles. It also offers a tool to test the necessity and sufficiency of particular interactions and conditions for vascular patterning and yields novel predictions that may be experimentally tested. Finally, this model provides a reference for further studies comparing the overall dynamics of tissue organization and formation by meristems in other plant organs and species.
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Affiliation(s)
- Mariana Benítez
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, México DF, Mexico
- Centro de Ciencias de la Complejidad C3, Universidad Nacional Autónoma de México, México DF, Mexico
| | - Jan Hejátko
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology, Masaryk University, Brno, Czech Republic
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32
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Fujita H, Kawaguchi M. Pattern formation by two-layer Turing system with complementarysynthesis. J Theor Biol 2013; 322:33-45. [DOI: 10.1016/j.jtbi.2013.01.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 12/06/2012] [Accepted: 01/11/2013] [Indexed: 10/27/2022]
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Otsuka K, Sugiyama M. Tissue organization of fasciated lateral roots of Arabidopsis mutants suggestive of the robust nature of outer layer patterning. JOURNAL OF PLANT RESEARCH 2012; 125:547-554. [PMID: 22258701 DOI: 10.1007/s10265-011-0471-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 12/16/2011] [Indexed: 05/27/2023]
Abstract
In three temperature-sensitive mutants of Arabidopsis, root redifferentiation 1 (rrd1), rrd2, and root initiation defective 4 (rid4), formation of fasciated lateral roots was previously observed under high temperature conditions of 28°C. When lateral roots were induced from explants of very young seedlings of these mutants by culture with exogenously supplied auxin at 28°C, expansion of lateral root primordia leading to lateral root fasciation occurred reproducibly and semi-synchronously with a high frequency. This experimental system allowed us to examine how radial organization of root tissues is altered in association with expansion of primordia. Analysis with various tissue-specific reporter genes indicated that in the fasciated lateral roots, cell files of the stele are increased markedly while the numbers of cortical and epidermal cell layers are not changed. This suggests that radial organization during root primordium development involves a mechanism that makes outer layer patterning more robust than inner layer patterning against unusual enlargement of the morphogenetic field.
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Affiliation(s)
- Kurataka Otsuka
- Botanical Gardens, Graduate School of Science, The University of Tokyo, Hakusan 3-7-1, Bunkyo-ku, Tokyo 112-0001, Japan.
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34
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Harrison LG, Adams RJ, Holloway DM. Dynamic regulation of growing domains for elongating and branching morphogenesis in plants. Biosystems 2012; 109:488-97. [PMID: 22483851 DOI: 10.1016/j.biosystems.2012.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 03/06/2012] [Accepted: 03/21/2012] [Indexed: 11/19/2022]
Abstract
With their continuous growth, understanding how plant shapes form is fundamentally linked to understanding how growth rates are controlled across different regions of the plant. Much of a plant's architecture is generated in shoots and roots, where fast growth in tips contrasts with slow growth in supporting stalks. Shapes can be determined by where the boundaries between fast- and slow-growing regions are positioned, determining whether tips elongate, branch, or cease to grow. Across plants, there is a diversity in the cell wall chemistry through which growth operates. However, prototypical morphologies, such as tip growth and branching, suggest there are common dynamic constraints in localizing chemical growth catalysts. We have used Turing-type reaction-diffusion mechanisms to model this spatial localization and the resulting growth trajectories, characterizing the chemistry-growth feedback necessary for maintaining tip growth and for inducing branching. The mechanism defining the boundaries between fast- and slow-growing regions not only affects tip shape, it must be able to form new boundaries when the pattern-forming dynamics break symmetry, for instance in the branching of a tip. In previous work, we used an arbitrary concentration threshold to switch between two dynamic regimes of the growth catalyst in order to define growth boundaries. Here, we present a chemical dynamic basis for this threshold, in which feedback between two pattern-forming mechanisms controls the extent of the regions in which fast growth occurs. This provides a general self-contained mechanism for growth control in plant morphogenesis (not relying on external cues) which can account for both simple tip extension and symmetry-breaking branching phenomena.
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Affiliation(s)
- Lionel G Harrison
- Chemistry Department, University of British Columbia, Vancouver, B.C., Canada
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Cytokinin signaling as a positional cue for patterning the apical-basal axis of the growing Arabidopsis shoot meristem. Proc Natl Acad Sci U S A 2012; 109:4002-7. [PMID: 22345559 DOI: 10.1073/pnas.1200636109] [Citation(s) in RCA: 161] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The transcription factor WUSCHEL (WUS) acts from a well-defined domain within the Arabidopsis thaliana shoot apical meristem (SAM) to maintain a stem cell niche. A negative-feedback loop involving the CLAVATA (CLV) signaling pathway regulates the number of WUS-expressing cells and provides the current paradigm for the homeostatic maintenance of stem cell numbers. Despite the continual turnover of cells in the SAM during development, the WUS domain remains patterned at a fixed distance below the shoot apex. Recent work has uncovered a positive-feedback loop between WUS function and the plant hormone cytokinin. Furthermore, loss of function of the cytokinin biosynthetic gene, LONELY GUY (LOG), results in a wus-like phenotype in rice. Herein, we find the Arabidopsis LOG4 gene is expressed in the SAM epidermis. We use this to develop a computational model representing a growing SAM to suggest the plausibility that apically derived cytokinin and CLV signaling, together, act as positional cues for patterning the WUS domain within the stem cell niche. Furthermore, model simulations backed by experimental data suggest a previously unknown negative feedback between WUS function and cytokinin biosynthesis in the Arabidopsis SAM epidermis. These results suggest a plausible dynamic feedback principle by which the SAM stem cell niche is patterned.
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36
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Jönsson H, Gruel J, Krupinski P, Troein C. On evaluating models in Computational Morphodynamics. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:103-110. [PMID: 22000039 DOI: 10.1016/j.pbi.2011.09.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 09/21/2011] [Accepted: 09/23/2011] [Indexed: 05/31/2023]
Abstract
Recent advances in experimental plant biology have led to an increased potential to investigate plant development at a systems level. The emerging research field of Computational Morphodynamics has the aim to lead this development by combining dynamic spatial experimental data with computational models of molecular networks, growth, and mechanics in a multicellular context. The increased number of published models may lead to a diversification of our understanding of the systems, and methods for evaluating, comparing, and sharing models are main challenges for the future. We will discuss this problem using ideas originating from physics and use recent computational models of plant development as examples.
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Affiliation(s)
- Henrik Jönsson
- Computational Biology and Biological Physics, Lund University, Sweden.
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Azpeitia E, Benítez M, Padilla-Longoria P, Espinosa-Soto C, Alvarez-Buylla ER. Dynamic network-based epistasis analysis: boolean examples. FRONTIERS IN PLANT SCIENCE 2011; 2:92. [PMID: 22645556 PMCID: PMC3355816 DOI: 10.3389/fpls.2011.00092] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 11/17/2011] [Indexed: 05/21/2023]
Abstract
In this article we focus on how the hierarchical and single-path assumptions of epistasis analysis can bias the inference of gene regulatory networks. Here we emphasize the critical importance of dynamic analyses, and specifically illustrate the use of Boolean network models. Epistasis in a broad sense refers to gene interactions, however, as originally proposed by Bateson, epistasis is defined as the blocking of a particular allelic effect due to the effect of another allele at a different locus (herein, classical epistasis). Classical epistasis analysis has proven powerful and useful, allowing researchers to infer and assign directionality to gene interactions. As larger data sets are becoming available, the analysis of classical epistasis is being complemented with computer science tools and system biology approaches. We show that when the hierarchical and single-path assumptions are not met in classical epistasis analysis, the access to relevant information and the correct inference of gene interaction topologies is hindered, and it becomes necessary to consider the temporal dynamics of gene interactions. The use of dynamical networks can overcome these limitations. We particularly focus on the use of Boolean networks that, like classical epistasis analysis, relies on logical formalisms, and hence can complement classical epistasis analysis and relax its assumptions. We develop a couple of theoretical examples and analyze them from a dynamic Boolean network model perspective. Boolean networks could help to guide additional experiments and discern among alternative regulatory schemes that would be impossible or difficult to infer without the elimination of these assumption from the classical epistasis analysis. We also use examples from the literature to show how a Boolean network-based approach has resolved ambiguities and guided epistasis analysis. Our article complements previous accounts, not only by focusing on the implications of the hierarchical and single-path assumption, but also by demonstrating the importance of considering temporal dynamics, and specifically introducing the usefulness of Boolean network models and also reviewing some key properties of network approaches.
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Affiliation(s)
- Eugenio Azpeitia
- Instituto de Ecología, Universidad Nacional Autónoma de MexicoMexico D.F., Mexico
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de MexicoMexico D.F., Mexico
| | - Mariana Benítez
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de MexicoMexico D.F., Mexico
- Department of Functional Genomics and Proteomics, Masaryk UniversityBrno, Czech Republic
- Central European Institute of Technology, Masaryk UniversityBrno, Czech Republic
| | - Pablo Padilla-Longoria
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de MexicoMexico D.F., Mexico
- Instituto de Investigaciones en Matemáticas Aplicadas y en SistemasMexico D.F., Mexico
| | - Carlos Espinosa-Soto
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de MexicoMexico D.F., Mexico
- Cinvestav-IPNIrapuato, Mexico
| | - Elena R. Alvarez-Buylla
- Instituto de Ecología, Universidad Nacional Autónoma de MexicoMexico D.F., Mexico
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de MexicoMexico D.F., Mexico
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38
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Fujita H, Kawaguchi M. Strategy for shoot meristem proliferation in plants. PLANT SIGNALING & BEHAVIOR 2011; 6:1851-1854. [PMID: 22067107 PMCID: PMC3329367 DOI: 10.4161/psb.6.11.17656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Shoot apical meristem (SAM) of plants harbors stem cells capable of generating the aerial tissues including reproductive organs. Therefore, it is very important for plants to control SAM proliferation and its density as a survival strategy. The SAM is regulated by the dynamics of a specific gene network, such as the WUS-CLV interaction of A. thaliana. By using a mathematical model, we previously proposed six possible SAM patterns in terms of the manner and frequency of stem cell proliferation. Two of these SAM patterns are predicted to generate either dichotomous or axillary shoot branch. Dichotomous shoot branches caused by this mechanism are characteristic of the earliest vascular plants, such as Cooksonia and Rhynia, but are observed in only a small minority of plant species of the present day. On the other hand, axillary branches are observed in the majority of plant species and are induced by a different dynamics of the feedback regulation between auxin and the asymmetric distribution of PIN auxin efflux carriers. During evolution, some plants may have adopted this auxin-PIN system to more strictly control SAM proliferation.
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Affiliation(s)
- Hironori Fujita
- Division of Symbiotic Systems, National Institute for Basic Biology, Okazaki, Japan.
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39
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Betsuyaku S, Sawa S, Yamada M. The Function of the CLE Peptides in Plant Development and Plant-Microbe Interactions. THE ARABIDOPSIS BOOK 2011; 9:e0149. [PMID: 22303273 PMCID: PMC3268505 DOI: 10.1199/tab.0149] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The CLAVATA3 (CLV3)/ENDOSPERM SURROUNDING REGION (ESR) (CLE) peptides consist of 12 or 13 amino acids, including hydroxylated proline residues that may or may not contain sugar modifications, and function in a non-cell-autonomous fashion. The CLE gene was first reported in Zea mays (maize) as an endosperm-specific gene, ESR, in 1997 (Opsahl-Ferstad et al., 1997). CLE genes encode secreted peptides that function in the extracellular space as intercellular signaling molecules and bind to cellular surface receptor-like proteins to transmit a signal. CLE peptides regulate various physiological and developmental processes and its signaling pathway are conserved in diverse land plants. Recent CLE functional studies have pointed to their significance in regulating meristematic activity in plant meristems, through the CLE-receptor kinase-WOX signaling node. CLV3 and CLE40 are responsible for maintenance of shoot apical meristem (SAM) and root apical meristem (RAM) function, regulating homeodomain transcription factors, WUSCHEL (WUS) and WUSCHEL-related homeobox 5 (WOX5), respectively. CLE and WOX form an interconnected and self-correcting feedback loop to provide robustness to stem cell homeostasis. CLE peptides are required for certain plant-microbe interactions, such as those that occur during legume symbiosis and phytopathogenic nematode infection. Understanding the molecular properties of CLE peptides may provide insight into plant cell-cell communication, and therefore also into plant-microbe interactions.
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Affiliation(s)
- Shigeyuki Betsuyaku
- Division of Life Sciences, Komaba Organization for Educational Excellence, Graduate School of Arts and Sciences, University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shinichiro Sawa
- Graduate School of Science and Technology, Kumamoto University, Kurokami 2-39-1, 860-8555 Kumamoto Japan
| | - Masashi Yamada
- Department of Biology and Institute for Genome Science and Policy Center for Systems Biology, Duke University, Durham, NC 27708, USA
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