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Chen J, Yu R, Li N, Deng Z, Zhang X, Zhao Y, Qu C, Yuan Y, Pan Z, Zhou Y, Li K, Wang J, Chen Z, Wang X, Wang X, He SN, Dong J, Deng XW, Chen H. Amyloplast sedimentation repolarizes LAZYs to achieve gravity sensing in plants. Cell 2023; 186:4788-4802.e15. [PMID: 37741279 PMCID: PMC10615846 DOI: 10.1016/j.cell.2023.09.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 08/04/2023] [Accepted: 09/14/2023] [Indexed: 09/25/2023]
Abstract
Gravity controls directional growth of plants, and the classical starch-statolith hypothesis proposed more than a century ago postulates that amyloplast sedimentation in specialized cells initiates gravity sensing, but the molecular mechanism remains uncharacterized. The LAZY proteins are known as key regulators of gravitropism, and lazy mutants show striking gravitropic defects. Here, we report that gravistimulation by reorientation triggers mitogen-activated protein kinase (MAPK) signaling-mediated phosphorylation of Arabidopsis LAZY proteins basally polarized in root columella cells. Phosphorylation of LAZY increases its interaction with several translocons at the outer envelope membrane of chloroplasts (TOC) proteins on the surface of amyloplasts, facilitating enrichment of LAZY proteins on amyloplasts. Amyloplast sedimentation subsequently guides LAZY to relocate to the new lower side of the plasma membrane in columella cells, where LAZY induces asymmetrical auxin distribution and root differential growth. Together, this study provides a molecular interpretation for the starch-statolith hypothesis: the organelle-movement-triggered molecular polarity formation.
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Affiliation(s)
- Jiayue Chen
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Renbo Yu
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Key Laboratory of Vegetable Research Center, Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Na Li
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Zhaoguo Deng
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Xinxin Zhang
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Yaran Zhao
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Chengfu Qu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Yanfang Yuan
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Zhexian Pan
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Yangyang Zhou
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Kunlun Li
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Jiajun Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Zhiren Chen
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Xiaoyi Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Xiaolian Wang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Shu-Nan He
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Juan Dong
- The Waksman Institute of Microbiology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA; Department of Plant Biology, Rutgers, the State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Xing Wang Deng
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Haodong Chen
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China.
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García-González J, van Gelderen K. Bundling up the Role of the Actin Cytoskeleton in Primary Root Growth. FRONTIERS IN PLANT SCIENCE 2021; 12:777119. [PMID: 34975959 PMCID: PMC8716943 DOI: 10.3389/fpls.2021.777119] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/11/2021] [Indexed: 05/19/2023]
Abstract
Primary root growth is required by the plant to anchor in the soil and reach out for nutrients and water, while dealing with obstacles. Efficient root elongation and bending depends upon the coordinated action of environmental sensing, signal transduction, and growth responses. The actin cytoskeleton is a highly plastic network that constitutes a point of integration for environmental stimuli and hormonal pathways. In this review, we present a detailed compilation highlighting the importance of the actin cytoskeleton during primary root growth and we describe how actin-binding proteins, plant hormones, and actin-disrupting drugs affect root growth and root actin. We also discuss the feedback loop between actin and root responses to light and gravity. Actin affects cell division and elongation through the control of its own organization. We remark upon the importance of longitudinally oriented actin bundles as a hallmark of cell elongation as well as the role of the actin cytoskeleton in protein trafficking and vacuolar reshaping during this process. The actin network is shaped by a plethora of actin-binding proteins; however, there is still a large gap in connecting the molecular function of these proteins with their developmental effects. Here, we summarize their function and known effects on primary root growth with a focus on their high level of specialization. Light and gravity are key factors that help us understand root growth directionality. The response of the root to gravity relies on hormonal, particularly auxin, homeostasis, and the actin cytoskeleton. Actin is necessary for the perception of the gravity stimulus via the repositioning of sedimenting statoliths, but it is also involved in mediating the growth response via the trafficking of auxin transporters and cell elongation. Furthermore, auxin and auxin analogs can affect the composition of the actin network, indicating a potential feedback loop. Light, in its turn, affects actin organization and hence, root growth, although its precise role remains largely unknown. Recently, fundamental studies with the latest techniques have given us more in-depth knowledge of the role and organization of actin in the coordination of root growth; however, there remains a lot to discover, especially in how actin organization helps cell shaping, and therefore root growth.
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Affiliation(s)
- Judith García-González
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- *Correspondence: Judith García-González,
| | - Kasper van Gelderen
- Plant Ecophysiology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
- Kasper van Gelderen,
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Su SH, Keith MA, Masson PH. Gravity Signaling in Flowering Plant Roots. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1290. [PMID: 33003550 PMCID: PMC7601833 DOI: 10.3390/plants9101290] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/24/2020] [Accepted: 09/27/2020] [Indexed: 12/28/2022]
Abstract
Roots typically grow downward into the soil where they anchor the plant and take up water and nutrients necessary for plant growth and development. While the primary roots usually grow vertically downward, laterals often follow a gravity set point angle that allows them to explore the surrounding environment. These responses can be modified by developmental and environmental cues. This review discusses the molecular mechanisms that govern root gravitropism in flowering plant roots. In this system, the primary site of gravity sensing within the root cap is physically separated from the site of curvature response at the elongation zone. Gravity sensing involves the sedimentation of starch-filled plastids (statoliths) within the columella cells of the root cap (the statocytes), which triggers a relocalization of plasma membrane-associated PIN auxin efflux facilitators to the lower side of the cell. This process is associated with the recruitment of RLD regulators of vesicular trafficking to the lower membrane by LAZY proteins. PIN relocalization leads to the formation of a lateral gradient of auxin across the root cap. Upon transmission to the elongation zone, this auxin gradient triggers a downward curvature. We review the molecular mechanisms that control this process in primary roots and discuss recent insights into the regulation of oblique growth in lateral roots and its impact on root-system architecture, soil exploration and plant adaptation to stressful environments.
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Affiliation(s)
| | | | - Patrick H. Masson
- Laboratory of Genetics, University of Wisconsin-Madison, 425G Henry Mall, Madison, WI 53706, USA; (S.-H.S.); (M.A.K.)
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de Bang L, Paez-Garcia A, Cannon AE, Chin S, Kolape J, Liao F, Sparks JA, Jiang Q, Blancaflor EB. Brassinosteroids Inhibit Autotropic Root Straightening by Modifying Filamentous-Actin Organization and Dynamics. FRONTIERS IN PLANT SCIENCE 2020; 11:5. [PMID: 32117357 PMCID: PMC7010715 DOI: 10.3389/fpls.2020.00005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 01/06/2020] [Indexed: 05/12/2023]
Abstract
When positioned horizontally, roots grow down toward the direction of gravity. This phenomenon, called gravitropism, is influenced by most of the major plant hormones including brassinosteroids. Epi-brassinolide (eBL) was previously shown to enhance root gravitropism, a phenomenon similar to the response of roots exposed to the actin inhibitor, latrunculin B (LatB). This led us to hypothesize that eBL might enhance root gravitropism through its effects on filamentous-actin (F-actin). This hypothesis was tested by comparing gravitropic responses of maize (Zea mays) roots treated with eBL or LatB. LatB- and eBL-treated roots displayed similar enhanced downward growth compared with controls when vertical roots were oriented horizontally. Moreover, the effects of the two compounds on root growth directionality were more striking on a slowly-rotating two-dimensional clinostat. Both compounds inhibited autotropism, a process in which the root straightened after the initial gravistimulus was withdrawn by clinorotation. Although eBL reduced F-actin density in chemically-fixed Z. mays roots, the impact was not as strong as that of LatB. Modification of F-actin organization after treatment with both compounds was also observed in living roots of barrel medic (Medicago truncatula) seedlings expressing genetically encoded F-actin reporters. Like in fixed Z. mays roots, eBL effects on F-actin in living M. truncatula roots were modest compared with those of LatB. Furthermore, live cell imaging revealed a decrease in global F-actin dynamics in hypocotyls of etiolated M. truncatula seedlings treated with eBL compared to controls. Collectively, our data indicate that eBL-and LatB-induced enhancement of root gravitropism can be explained by inhibited autotropic root straightening, and that eBL affects this process, in part, by modifying F-actin organization and dynamics.
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Affiliation(s)
- Louise de Bang
- Noble Research Institute LLC, Ardmore, OK, United States
- Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Ashley E. Cannon
- Noble Research Institute LLC, Ardmore, OK, United States
- Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Sabrina Chin
- Noble Research Institute LLC, Ardmore, OK, United States
| | - Jaydeep Kolape
- Noble Research Institute LLC, Ardmore, OK, United States
- Center for Biotechnology, University of Nebraska—Lincoln, Lincoln, NE, United States
| | - Fuqi Liao
- Noble Research Institute LLC, Ardmore, OK, United States
| | - J. Alan Sparks
- Noble Research Institute LLC, Ardmore, OK, United States
| | - Qingzhen Jiang
- Noble Research Institute LLC, Ardmore, OK, United States
| | - Elison B. Blancaflor
- Noble Research Institute LLC, Ardmore, OK, United States
- *Correspondence: Elison B. Blancaflor,
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5
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Nakamura M, Nishimura T, Morita MT. Gravity sensing and signal conversion in plant gravitropism. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3495-3506. [PMID: 30976802 DOI: 10.1093/jxb/erz158] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 04/08/2019] [Indexed: 05/17/2023]
Abstract
Plant organs control their growth orientation in response to gravity. Within gravity-sensing cells, the input (gravity sensing) and signal conversion (gravity signalling) progress sequentially. The cells contain a number of high-density, starch-accumulating amyloplasts, which sense gravity when they reposition themselves by sedimentation to the bottom of the cell when the plant organ is re-orientated. This triggers the next step of gravity signalling, when the physical signal generated by the sedimentation of the amyloplasts is converted into a biochemical signal, which redirects auxin transport towards the lower flank of the plant organ. This review focuses on recent advances in our knowledge of the regulatory mechanisms that underlie amyloplast sedimentation and the system by which this is perceived, and on recent progress in characterising the factors that play significant roles in gravity signalling by which the sedimentation is linked to the regulation of directional auxin transport. Finally, we discuss the contribution of gravity signalling factors to the mechanisms that control the gravitropic set-point angle.
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Affiliation(s)
- Moritaka Nakamura
- Division of Plant Environmental Responses, National Institute for Basic Biology, Okazaki, Japan
| | - Takeshi Nishimura
- Division of Plant Environmental Responses, National Institute for Basic Biology, Okazaki, Japan
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
| | - Miyo Terao Morita
- Division of Plant Environmental Responses, National Institute for Basic Biology, Okazaki, Japan
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
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6
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Bérut A, Chauvet H, Legué V, Moulia B, Pouliquen O, Forterre Y. Gravisensors in plant cells behave like an active granular liquid. Proc Natl Acad Sci U S A 2018; 115:5123-5128. [PMID: 29712863 PMCID: PMC5960325 DOI: 10.1073/pnas.1801895115] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Plants are able to sense and respond to minute tilt from the vertical direction of the gravity, which is key to maintain their upright posture during development. However, gravisensing in plants relies on a peculiar sensor made of microsize starch-filled grains (statoliths) that sediment and form tiny granular piles at the bottom of the cell. How such a sensor can detect inclination is unclear, as granular materials like sand are known to display flow threshold and finite avalanche angle due to friction and interparticle jamming. Here, we address this issue by combining direct visualization of statolith avalanches in plant cells and experiments in biomimetic cells made of microfluidic cavities filled with a suspension of heavy Brownian particles. We show that, despite their granular nature, statoliths move and respond to the weakest angle, as a liquid clinometer would do. Comparison between the biological and biomimetic systems reveals that this liquid-like behavior comes from the cell activity, which agitates statoliths with an apparent temperature one order of magnitude larger than actual temperature. Our results shed light on the key role of active fluctuations of statoliths for explaining the remarkable sensitivity of plants to inclination. Our study also provides support to a recent scenario of gravity perception in plants, by bridging the active granular rheology of statoliths at the microscopic level to the macroscopic gravitropic response of the plant.
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Affiliation(s)
- Antoine Bérut
- Aix-Marseille Univ, CNRS, IUSTI (Institut Universitaire des Systèmes Thermiques Industriels), 13013 Marseille, France
| | - Hugo Chauvet
- Aix-Marseille Univ, CNRS, IUSTI (Institut Universitaire des Systèmes Thermiques Industriels), 13013 Marseille, France
- Université Clermont Auvergne, INRA, PIAF, F-63000 Clermont-Ferrand, France
| | - Valérie Legué
- Université Clermont Auvergne, INRA, PIAF, F-63000 Clermont-Ferrand, France
| | - Bruno Moulia
- Université Clermont Auvergne, INRA, PIAF, F-63000 Clermont-Ferrand, France
| | - Olivier Pouliquen
- Aix-Marseille Univ, CNRS, IUSTI (Institut Universitaire des Systèmes Thermiques Industriels), 13013 Marseille, France
| | - Yoël Forterre
- Aix-Marseille Univ, CNRS, IUSTI (Institut Universitaire des Systèmes Thermiques Industriels), 13013 Marseille, France;
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8
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Singh M, Gupta A, Laxmi A. Striking the Right Chord: Signaling Enigma during Root Gravitropism. FRONTIERS IN PLANT SCIENCE 2017; 8:1304. [PMID: 28798760 PMCID: PMC5529344 DOI: 10.3389/fpls.2017.01304] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/11/2017] [Indexed: 05/29/2023]
Abstract
Plants being sessile can often be judged as passive acceptors of their environment. However, plants are actually even more active in responding to the factors from their surroundings. Plants do not have eyes, ears or vestibular system like animals, still they "know" which way is up and which way is down? This is facilitated by receptor molecules within plant which perceive changes in internal and external conditions such as light, touch, obstacles; and initiate signaling pathways that enable the plant to react. Plant responses that involve a definite and specific movement are called "tropic" responses. Perhaps the best known and studied tropisms are phototropism, i.e., response to light, and geotropism, i.e., response to gravity. A robust root system is vital for plant growth as it can provide physical anchorage to soil as well as absorb water, nutrients and essential minerals from soil efficiently. Gravitropic responses of both primary as well as lateral root thus become critical for plant growth and development. The molecular mechanisms of root gravitropism has been delved intensively, however, the mechanism behind how the potential energy of gravity stimulus converts into a biochemical signal in vascular plants is still unknown, due to which gravity sensing in plants still remains one of the most fascinating questions in molecular biology. Communications within plants occur through phytohormones and other chemical substances produced in plants which have a developmental or physiological effect on growth. Here, we review current knowledge of various intrinsic signaling mechanisms that modulate root gravitropism in order to point out the questions and emerging developments in plant directional growth responses. We are also discussing the roles of sugar signals and their interaction with phytohormone machinery, specifically in context of root directional responses.
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Affiliation(s)
- Manjul Singh
- National Institute of Plant Genome ResearchNew Delhi, India
- Interdisciplinary Centre for Plant Genomics, University of Delhi South CampusNew Delhi, India
| | - Aditi Gupta
- National Institute of Plant Genome ResearchNew Delhi, India
- Interdisciplinary Centre for Plant Genomics, University of Delhi South CampusNew Delhi, India
| | - Ashverya Laxmi
- National Institute of Plant Genome ResearchNew Delhi, India
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Pouliquen O, Forterre Y, Bérut A, Chauvet H, Bizet F, Legué V, Moulia B. A new scenario for gravity detection in plants: the position sensor hypothesis. Phys Biol 2017; 14:035005. [PMID: 28535150 DOI: 10.1088/1478-3975/aa6876] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The detection of gravity plays a fundamental role during the growth and evolution of plants. Although progress has been made in our understanding of the molecular, cellular and physical mechanisms involved in the gravity detection, a coherent scenario consistent with all the observations is still lacking. In this special issue article, we discuss recent experiments showing that the response to inclination of shoots is independent of the gravity intensity, meaning that the gravity sensor detects an inclination and not a force. This result questions some of the commonly accepted hypotheses and leads to propose a new 'position sensor hypothesis'. The implications of this new scenario are discussed in light of the different observations available in the literature.
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Affiliation(s)
- O Pouliquen
- Aix Marseille University, CNRS, IUSTI, Marseille, France
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10
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Chauvet H, Pouliquen O, Forterre Y, Legué V, Moulia B. Inclination not force is sensed by plants during shoot gravitropism. Sci Rep 2016; 6:35431. [PMID: 27739470 PMCID: PMC5064399 DOI: 10.1038/srep35431] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 09/27/2016] [Indexed: 12/03/2022] Open
Abstract
Gravity perception plays a key role in how plants develop and adapt to environmental changes. However, more than a century after the pioneering work of Darwin, little is known on the sensing mechanism. Using a centrifugal device combined with growth kinematics imaging, we show that shoot gravitropic responses to steady levels of gravity in four representative angiosperm species is independent of gravity intensity. All gravitropic responses tested are dependent only on the angle of inclination from the direction of gravity. We thus demonstrate that shoot gravitropism is stimulated by sensing inclination not gravitational force or acceleration as previously believed. This contrasts with the otolith system in the internal ear of vertebrates and explains the robustness of the control of growth direction by plants despite perturbations like wind shaking. Our results will help retarget the search for the molecular mechanism linking shifting statoliths to signal transduction.
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Affiliation(s)
- Hugo Chauvet
- Aix-Marseille Univ., CNRS, IUSTI UMR 7343, 13453 Marseille Cedex 13, France.,Integrative Physics and Physiology of Trees (PIAF), INRA, Univ. Clermont-Auvergne, 63000 Clermont-Ferrand, France
| | - Olivier Pouliquen
- Aix-Marseille Univ., CNRS, IUSTI UMR 7343, 13453 Marseille Cedex 13, France
| | - Yoël Forterre
- Aix-Marseille Univ., CNRS, IUSTI UMR 7343, 13453 Marseille Cedex 13, France
| | - Valérie Legué
- Integrative Physics and Physiology of Trees (PIAF), INRA, Univ. Clermont-Auvergne, 63000 Clermont-Ferrand, France
| | - Bruno Moulia
- Integrative Physics and Physiology of Trees (PIAF), INRA, Univ. Clermont-Auvergne, 63000 Clermont-Ferrand, France
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11
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Zou JJ, Zheng ZY, Xue S, Li HH, Wang YR, Le J. The role of Arabidopsis Actin-Related Protein 3 in amyloplast sedimentation and polar auxin transport in root gravitropism. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:5325-5337. [PMID: 27473572 PMCID: PMC5049384 DOI: 10.1093/jxb/erw294] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Gravitropism is vital for shaping directional plant growth in response to the forces of gravity. Signals perceived in the gravity-sensing cells can be converted into biochemical signals and transmitted. Sedimentation of amyloplasts in the columella cells triggers asymmetric auxin redistribution in root tips, leading to downward root growth. The actin cytoskeleton is thought to play an important role in root gravitropism, although the molecular mechanism has not been resolved. DISTORTED1 (DIS1) encodes the ARP3 subunit of the Arabidopsis Actin-Related Protein 2/3 (ARP2/3) complex, and the ARP3/DIS1 mutant dis1-1 showed delayed root curvature after gravity stimulation. Microrheological analysis revealed that the high apparent viscosity within dis1-1 central columella cells is closely associated with abnormal movement trajectories of amyloplasts. Analysis using a sensitive auxin input reporter DII-VENUS showed that asymmetric auxin redistribution was reduced in the root tips of dis1-1, and the actin-disrupting drug Latrunculin B increased the asymmetric auxin redistribution. An uptake assay using the membrane-selective dye FM4-64 indicated that endocytosis was decelerated in dis1-1 root epidermal cells. Treatment and wash-out with Brefeldin A, which inhibits protein transport from the endoplasmic reticulum to the Golgi apparatus, showed that cycling of the auxin-transporter PIN-FORMED (PIN) proteins to the plasma membrane was also suppressed in dis1-1 roots. The results reveal that ARP3/DIS1 acts in root gravitropism by affecting amyloplast sedimentation and PIN-mediated polar auxin transport through regulation of PIN protein trafficking.
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Affiliation(s)
- Jun-Jie Zou
- Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Zhong-Yu Zheng
- Key Laboratory of Microgravity, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shan Xue
- Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Han-Hai Li
- Key Laboratory of Microgravity, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yu-Ren Wang
- Key Laboratory of Microgravity, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jie Le
- Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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12
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Wang HZ, Yang KZ, Zou JJ, Zhu LL, Xie ZD, Morita MT, Tasaka M, Friml J, Grotewold E, Beeckman T, Vanneste S, Sack F, Le J. Transcriptional regulation of PIN genes by FOUR LIPS and MYB88 during Arabidopsis root gravitropism. Nat Commun 2015; 6:8822. [PMID: 26578169 PMCID: PMC4673497 DOI: 10.1038/ncomms9822] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Accepted: 10/07/2015] [Indexed: 12/29/2022] Open
Abstract
PIN proteins are auxin export carriers that direct intercellular auxin flow and in turn regulate many aspects of plant growth and development including responses to environmental changes. The Arabidopsis R2R3-MYB transcription factor FOUR LIPS (FLP) and its paralogue MYB88 regulate terminal divisions during stomatal development, as well as female reproductive development and stress responses. Here we show that FLP and MYB88 act redundantly but differentially in regulating the transcription of PIN3 and PIN7 in gravity-sensing cells of primary and lateral roots. On the one hand, FLP is involved in responses to gravity stimulation in primary roots, whereas on the other, FLP and MYB88 function complementarily in establishing the gravitropic set-point angles of lateral roots. Our results support a model in which FLP and MYB88 expression specifically determines the temporal-spatial patterns of PIN3 and PIN7 transcription that are closely associated with their preferential functions during root responses to gravity. Plants respond to reorientation by altering the distribution of the plant hormone auxin causing roots to bend towards gravity. Here Wang et al. find that expression of the PIN3 and PIN7 auxin transporters in gravity sensing cells is controlled by concerted action of the FLP and MYB88 transcription factors.
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Affiliation(s)
- Hong-Zhe Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan (Fragrant Hill), Haidian, Beijing 100093, China.,University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Ke-Zhen Yang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan (Fragrant Hill), Haidian, Beijing 100093, China
| | - Jun-Jie Zou
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan (Fragrant Hill), Haidian, Beijing 100093, China
| | - Ling-Ling Zhu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan (Fragrant Hill), Haidian, Beijing 100093, China.,University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Zi Dian Xie
- Department of Molecular Genetics, Center for Applied Plant Sciences, The Ohio State University, Columbus, Ohio 43210, USA
| | - Miyo Terao Morita
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Masao Tasaka
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Jiří Friml
- Institute of Science and Technology of Austria, Am Campus 1, Klosterneuburg 3400, Austria
| | - Erich Grotewold
- Department of Molecular Genetics, Center for Applied Plant Sciences, The Ohio State University, Columbus, Ohio 43210, USA
| | - Tom Beeckman
- Department of Plant Systems Biology, VIB, Ghent B-9052, Belgium.,Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent B-9052, Belgium
| | - Steffen Vanneste
- Department of Plant Systems Biology, VIB, Ghent B-9052, Belgium.,Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent B-9052, Belgium
| | - Fred Sack
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Jie Le
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan (Fragrant Hill), Haidian, Beijing 100093, China
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