1
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Flubacher N, Baltenweck R, Hugueney P, Fischer J, Thines E, Riemann M, Nick P, Khattab IM. The fungal metabolite 4-hydroxyphenylacetic acid from Neofusicoccum parvum modulates defence responses in grapevine. PLANT, CELL & ENVIRONMENT 2023; 46:3575-3591. [PMID: 37431974 DOI: 10.1111/pce.14670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 06/28/2023] [Accepted: 07/04/2023] [Indexed: 07/12/2023]
Abstract
In a consequence of global warming, grapevine trunk diseases (GTDs) have become a pertinent problem to viticulture, because endophytic fungi can turn necrotrophic upon host stress killing the plant. In Neofusicoccum parvum Bt-67, plant-derived ferulic acid makes the fungus release Fusicoccin aglycone triggering plant cell death. Now, we show that the absence of ferulic acid lets the fungus secrete 4-hydroxyphenylacetic acid (4-HPA), mimicking the effect of auxins on grapevine defence and facilitating fungal spread. Using Vitis suspension cells, we dissected the mode of action of 4-HPA during defence triggered by the bacterial cell-death elicitor, harpin. Early responses (cytoskeletal remodelling and calcium influx) are inhibited, as well as the expression of Stilbene Synthase 27 and phytoalexin accumulation. In contrast to other auxins, 4-HPA quells transcripts for the auxin conjugating GRETCHEN HAGEN 3. We suggest that 4-HPA is a key component of the endophytic phase of N. parvum Bt-67 preventing host cell death. Therefore, our study paves the way to understand how GTDs regulate their latent phase for successful colonisation, before turning necrotrophic and killing the vines.
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Affiliation(s)
- Noemi Flubacher
- Department of Molecular Cell Biology, Joseph Gottlieb Kölreuter Institute of Plant Science, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | | | | | - Jochen Fischer
- Institut für Biotechnologie und Wirkstoff-Forschung gGmbH, Mainz, Germany
| | - Eckhard Thines
- Institut für Biotechnologie und Wirkstoff-Forschung gGmbH, Mainz, Germany
| | - Michael Riemann
- Department of Molecular Cell Biology, Joseph Gottlieb Kölreuter Institute of Plant Science, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Peter Nick
- Department of Molecular Cell Biology, Joseph Gottlieb Kölreuter Institute of Plant Science, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Islam M Khattab
- Department of Molecular Cell Biology, Joseph Gottlieb Kölreuter Institute of Plant Science, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute for Biological Interfaces 5, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Department of Horticulture, Faculty of Agriculture, Damanhour University, Damanhour, Egypt
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2
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Cui X, Zou M, Li J. Basally distributed actin array drives embryonic hypocotyl elongation during the seed-to-seedling transition in Arabidopsis. THE NEW PHYTOLOGIST 2023; 240:191-206. [PMID: 37537721 DOI: 10.1111/nph.19149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 06/27/2023] [Indexed: 08/05/2023]
Abstract
Seed germination is a vital developmental transition for the production of progeny by sexual reproduction in spermatophytes. The seed-to-seedling transition is predominately driven by hypocotyl cell elongation. However, the mechanism that underlies hypocotyl growth remains largely unknown. In this study, we characterized the actin array reorganization in embryonic hypocotyl epidermal cells. Live-cell imaging revealed a basally organized actin array formed during hypocotyl cell elongation. This polarized actin assembly is a barrel-shaped network, which comprises a backbone of longitudinally aligned actin cables and a fine actin cap linking these cables. We provide genetic evidence that the basal actin array formation requires formin-mediated actin polymerization and directional movement of actin filaments powered by myosin XIs. In fh1-1 and xi3ko mutants, actin filaments failed to reorganize into the basal actin array, and the hypocotyl cell elongation was inhibited compared with wild-type plants. Collectively, our work uncovers the molecular mechanisms for basal actin array assembly and demonstrates the connection between actin polarization and hypocotyl elongation during seed-to-seedling transition.
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Affiliation(s)
- Xuan Cui
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Minxia Zou
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Jiejie Li
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing, 100875, China
- Key Laboratory of Cell Proliferation and Regulation of Ministry of Education, College of Life Science, Beijing Normal University, Beijing, 100875, China
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Kim H, Jang J, Seomun S, Yoon Y, Jang G. Division of cortical cells is regulated by auxin in Arabidopsis roots. FRONTIERS IN PLANT SCIENCE 2022; 13:953225. [PMID: 36186058 PMCID: PMC9515965 DOI: 10.3389/fpls.2022.953225] [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: 05/25/2022] [Accepted: 07/06/2022] [Indexed: 06/16/2023]
Abstract
The root cortex transports water and nutrients absorbed by the root epidermis into the vasculature and stores substances such as starch, resins, and essential oils. The cortical cells are also deeply involved in determining epidermal cell fate. In Arabidopsis thaliana roots, the cortex is composed of a single cell layer generated by a single round of periclinal division of the cortex/endodermis initials. To further explore cortex development, we traced the development of the cortex by counting cortical cells. Unlike vascular cells, whose number increased during the development of root apical meristem (RAM), the number of cortical cells did not change, indicating that cortical cells do not divide during RAM development. However, auxin-induced cortical cell division, and this finding was confirmed by treatment with the auxin transport inhibitor N-1-naphthylphthalamic acid (NPA) and examining transgenic plants harboring CO2::ΔARF5, in which cortical expression of truncated AUXIN RESPONSE FACTOR5 (ΔARF5) induces auxin responses. NPA-induced cortical auxin accumulation and CO2::ΔARF5-mediated cortical auxin response induced anticlinal and periclinal cell divisions, thus increasing the number of cortical cells. These findings reveal a tight link between auxin and cortical cell division, suggesting that auxin is a key player in determining root cortical cell division.
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Affiliation(s)
- Huijin Kim
- School of Biological Sciences and Technology, Chonnam National University, Gwangju, South Korea
| | - Jinwoo Jang
- School of Biological Sciences and Technology, Chonnam National University, Gwangju, South Korea
| | - Subhin Seomun
- School of Biological Sciences and Technology, Chonnam National University, Gwangju, South Korea
| | - Youngdae Yoon
- Department of Environmental Health Science, Konkuk University, Seoul, South Korea
| | - Geupil Jang
- School of Biological Sciences and Technology, Chonnam National University, Gwangju, South Korea
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Xu X, Hummel S, Harter K, Kolukisaoglu Ü, Riemann M, Nick P. The Minus-End-Directed Kinesin OsDLK Shuttles to the Nucleus and Modulates the Expression of Cold-Box Factor 4. Int J Mol Sci 2022; 23:ijms23116291. [PMID: 35682970 PMCID: PMC9181729 DOI: 10.3390/ijms23116291] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 02/04/2023] Open
Abstract
The transition to terrestrial plants was accompanied by a progressive loss of microtubule minus-end-directed dynein motors. Instead, the minus-end-directed class-XIV kinesins expanded considerably, likely related to novel functions. One of these motors, OsDLK (Dual Localisation Kinesin from rice), decorates cortical microtubules but moves into the nucleus in response to cold stress. This analysis of loss-of-function mutants in rice indicates that OsDLK participates in cell elongation during development. Since OsDLK harbours both a nuclear localisation signal and a putative leucin zipper, we asked whether the cold-induced import of OsDLK into the nucleus might correlate with specific DNA binding. Conducting a DPI-ELISA screen with recombinant OsDLKT (lacking the motor domain), we identified the Opaque2 motif as the most promising candidate. This motif is present in the promoter of NtAvr9/Cf9, the tobacco homologue of Cold-Box Factor 4, a transcription factor involved in cold adaptation. A comparative study revealed that the cold-induced accumulation of NtAvr9/Cfp9 was specifically quelled in transgenic BY-2 cells overexpressing OsDLK-GFP. These findings are discussed as a working model, where, in response to cold stress, OsDLK partitions from cortical microtubules at the plasma membrane into the nucleus and specifically modulates the expression of genes involved in cold adaptation.
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Affiliation(s)
- Xiaolu Xu
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, D-76131 Karlsruhe, Germany;
- Correspondence: (X.X.); (P.N.)
| | - Sabine Hummel
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, D-72076 Tübingen, Germany; (S.H.); (K.H.); (Ü.K.)
| | - Klaus Harter
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, D-72076 Tübingen, Germany; (S.H.); (K.H.); (Ü.K.)
| | - Üner Kolukisaoglu
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, D-72076 Tübingen, Germany; (S.H.); (K.H.); (Ü.K.)
| | - Michael Riemann
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, D-76131 Karlsruhe, Germany;
| | - Peter Nick
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, D-76131 Karlsruhe, Germany;
- Correspondence: (X.X.); (P.N.)
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Ruiz-Molina N, Parsons J, Schroeder S, Posten C, Reski R, Decker EL. Process Engineering of Biopharmaceutical Production in Moss Bioreactors via Model-Based Description and Evaluation of Phytohormone Impact. Front Bioeng Biotechnol 2022; 10:837965. [PMID: 35252145 PMCID: PMC8891706 DOI: 10.3389/fbioe.2022.837965] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/24/2022] [Indexed: 12/24/2022] Open
Abstract
The moss Physcomitrella is an interesting production host for recombinant biopharmaceuticals. Here we produced MFHR1, a synthetic complement regulator which has been proposed for the treatment of diseases associated to the complement system as part of human innate immunity. We studied the impact of different operation modes for the production process in 5 L stirred-tank photobioreactors. The total amount of recombinant protein was doubled by using fed-batch or batch compared to semi-continuous operation, although the maximum specific productivity (mg MFHR1/g FW) increased just by 35%. We proposed an unstructured kinetic model which fits accurately with the experimental data in batch and semi-continuous operation under autotrophic conditions with 2% CO2 enrichment. The model is able to predict recombinant protein production, nitrate uptake and biomass growth, which is useful for process control and optimization. We investigated strategies to further increase MFHR1 production. While mixotrophic and heterotrophic conditions decreased the MFHR1-specific productivity compared to autotrophic conditions, addition of the phytohormone auxin (NAA, 10 µM) to the medium enhanced it by 470% in shaken flasks and up to 230% and 260%, in batch and fed-batch bioreactors, respectively. Supporting this finding, the auxin-synthesis inhibitor L-kynurenine (100 µM) decreased MFHR1 production significantly by 110% and 580% at day 7 and 18, respectively. Expression analysis revealed that the MFHR1 transgene, driven by the Physcomitrella actin5 (PpAct5) promoter, was upregulated 16 h after NAA addition and remained enhanced over the whole process, whereas the auxin-responsive gene PpIAA1A was upregulated within the first 2 hours, indicating that the effect of auxin on PpAct5 promoter-driven expression is indirect. Furthermore, the day of NAA supplementation was crucial, leading to an up to 8-fold increase of MFHR1-specific productivity (0.82 mg MFHR1/g fresh weight, 150 mg accumulated over 7 days) compared to the productivity reported previously. Our findings are likely to be applicable to other plant-based expression systems to increase biopharmaceutical production and yields.
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Affiliation(s)
- Natalia Ruiz-Molina
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Juliana Parsons
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Sina Schroeder
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Clemens Posten
- Institute of Process Engineering in Life Sciences III Bioprocess Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Eva L. Decker
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- *Correspondence: Eva L. Decker,
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Jaeger R, Moody LA. A fundamental developmental transition in Physcomitrium patens is regulated by evolutionarily conserved mechanisms. Evol Dev 2021; 23:123-136. [PMID: 33822471 DOI: 10.1111/ede.12376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 03/09/2021] [Accepted: 03/11/2021] [Indexed: 01/15/2023]
Abstract
One of the most defining moments in history was the colonization of land by plants approximately 470 million years ago. The transition from water to land was accompanied by significant changes in the plant body plan, from those than resembled filamentous representatives of the charophytes, the sister group to land plants, to those that were morphologically complex and capable of colonizing harsher habitats. The moss Physcomitrium patens (also known as Physcomitrella patens) is an extant representative of the bryophytes, the earliest land plant lineage. The protonema of P. patens emerges from spores from a chloronemal initial cell, which can divide to self-renew to produce filaments of chloronemal cells. A chloronemal initial cell can differentiate into a caulonemal initial cell, which can divide and self-renew to produce filaments of caulonemal cells, which branch extensively and give rise to three-dimensional shoots. The process by which a chloronemal initial cell differentiates into a caulonemal initial cell is tightly regulated by auxin-induced remodeling of the actin cytoskeleton. Studies have revealed that the genetic mechanisms underpinning this transition also regulate tip growth and differentiation in diverse plant taxa. This review summarizes the known cellular and molecular mechanisms underpinning the chloronema to caulonema transition in P. patens.
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Affiliation(s)
- Richard Jaeger
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Laura A Moody
- Department of Plant Sciences, University of Oxford, Oxford, UK
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7
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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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Arieti RS, Staiger CJ. Auxin-induced actin cytoskeleton rearrangements require AUX1. THE NEW PHYTOLOGIST 2020; 226:441-459. [PMID: 31859367 PMCID: PMC7154765 DOI: 10.1111/nph.16382] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 12/10/2019] [Indexed: 05/06/2023]
Abstract
The actin cytoskeleton is required for cell expansion and implicated in cellular responses to the phytohormone auxin. However, the mechanisms that coordinate auxin signaling, cytoskeletal remodeling and cell expansion are poorly understood. Previous studies examined long-term actin cytoskeleton responses to auxin, but plants respond to auxin within minutes. Before this work, an extracellular auxin receptor - rather than the auxin transporter AUXIN RESISTANT 1 (AUX1) - was considered to precede auxin-induced cytoskeleton reorganization. In order to correlate actin array organization and dynamics with degree of cell expansion, quantitative imaging tools established baseline actin organization and illuminated individual filament behaviors in root epidermal cells under control conditions and after indole-3-acetic acid (IAA) application. We evaluated aux1 mutant actin organization responses to IAA and the membrane-permeable auxin 1-naphthylacetic acid (NAA). Cell length predicted actin organization and dynamics in control roots; short-term IAA treatments stimulated denser and more parallel, longitudinal arrays by inducing filament unbundling within minutes. Although AUX1 is necessary for full actin rearrangements in response to auxin, cytoplasmic auxin (i.e. NAA) stimulated a lesser response. Actin filaments became more 'organized' after IAA stopped elongation, refuting the hypothesis that 'more organized' actin arrays universally correlate with rapid growth. Short-term actin cytoskeleton response to auxin requires AUX1 and/or cytoplasmic auxin.
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Affiliation(s)
- Ruthie S. Arieti
- Department of Biological SciencesPurdue UniversityWest LafayetteIN47907‐2064USA
- Purdue University Interdisciplinary Life Sciences Graduate Program (PULSe)Purdue UniversityWest LafayetteIN47907USA
- Center for Plant BiologyPurdue UniversityWest LafayetteIN47907USA
| | - Christopher J. Staiger
- Department of Biological SciencesPurdue UniversityWest LafayetteIN47907‐2064USA
- Center for Plant BiologyPurdue UniversityWest LafayetteIN47907USA
- Department of Botany and Plant PathologyPurdue UniversityWest LafayetteIN47907USA
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9
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Winnicki K. The Winner Takes It All: Auxin-The Main Player during Plant Embryogenesis. Cells 2020; 9:E606. [PMID: 32138372 PMCID: PMC7140527 DOI: 10.3390/cells9030606] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 02/21/2020] [Accepted: 02/27/2020] [Indexed: 12/11/2022] Open
Abstract
In plants, the first asymmetrical division of a zygote leads to the formation of two cells with different developmental fates. The establishment of various patterns relies on spatial and temporal gene expression, however the precise mechanism responsible for embryonic patterning still needs elucidation. Auxin seems to be the main player which regulates embryo development and controls expression of various genes in a dose-dependent manner. Thus, local auxin maxima and minima which are provided by polar auxin transport underlie cell fate specification. Diverse auxin concentrations in various regions of an embryo would easily explain distinct cell identities, however the question about the mechanism of cellular patterning in cells exposed to similar auxin concentrations still remains open. Thus, specification of cell fate might result not only from the cell position within an embryo but also from events occurring before and during mitosis. This review presents the impact of auxin on the orientation of the cell division plane and discusses the mechanism of auxin-dependent cytoskeleton alignment. Furthermore, close attention is paid to auxin-induced calcium fluxes, which regulate the activity of MAPKs during postembryonic development and which possibly might also underlie cellular patterning during embryogenesis.
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Affiliation(s)
- Konrad Winnicki
- Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lódź, Poland
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10
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Awwad F, Bertrand G, Grandbois M, Beaudoin N. Auxin protects Arabidopsis thaliana cell suspension cultures from programmed cell death induced by the cellulose biosynthesis inhibitors thaxtomin A and isoxaben. BMC PLANT BIOLOGY 2019; 19:512. [PMID: 31752698 PMCID: PMC6873746 DOI: 10.1186/s12870-019-2130-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 11/11/2019] [Indexed: 05/22/2023]
Abstract
BACKGROUND Thaxtomin A (TA) is a natural cellulose biosynthesis inhibitor (CBI) synthesized by the potato common scab-causing pathogen Streptomyces scabies. Inhibition of cellulose synthesis by TA compromises cell wall organization and integrity, leading to the induction of an atypical program of cell death (PCD). These processes may facilitate S. scabies entry into plant tissues. To study the mechanisms that regulate the induction of cell death in response to inhibition of cellulose synthesis, we used Arabidopsis thaliana cell suspension cultures treated with two structurally different CBIs, TA and the herbicide isoxaben (IXB). RESULTS The induction of cell death by TA and IXB was abrogated following pretreatment with the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) and the natural auxin indole-3-acetic acid (IAA). The addition of auxin efflux inhibitors also inhibited the CBI-mediated induction of PCD. This effect may be due to intracellular accumulation of auxin. Auxin has a wide range of effects in plant cells, including a role in the control of cell wall composition and rigidity to facilitate cell elongation. Using Atomic Force Microscopy (AFM)-based force spectroscopy, we found that inhibition of cellulose synthesis by TA and IXB in suspension-cultured cells decreased cell wall stiffness to a level slightly different than that caused by auxin. However, the cell wall stiffness in cells pretreated with auxin prior to CBI treatment was equivalent to that of cells treated with auxin only. CONCLUSIONS Addition of auxin to Arabidopsis cell suspension cultures prevented the TA- and IXB-mediated induction of cell death. Cell survival was also stimulated by inhibition of polar auxin transport during CBI-treatment. Inhibition of cellulose synthesis perturbed cell wall mechanical properties of Arabidopsis cells. Auxin treatment alone or with CBI also decreased cell wall stiffness, showing that the mechanical properties of the cell wall perturbed by CBIs were not restored by auxin. However, since auxin's effects on the cell wall stiffness apparently overrode those induced by CBIs, we suggest that auxin may limit the impact of CBIs by restoring its own transport and/or by stabilizing the plasma membrane - cell wall - cytoskeleton continuum.
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Affiliation(s)
- Fatima Awwad
- Centre SÈVE, Département de biologie, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada
- Present address: Groupe de Recherche en Biologie végétale, Département de chimie, biochimie et physique, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, G9A 5H7, Canada
| | - Guillaume Bertrand
- Institut de Pharmacologie de Sherbrooke, Département de pharmacologie et physiologie, Université de Sherbrooke, Sherbrooke, Québec, J1H 5N4, Canada
| | - Michel Grandbois
- Institut de Pharmacologie de Sherbrooke, Département de pharmacologie et physiologie, Université de Sherbrooke, Sherbrooke, Québec, J1H 5N4, Canada
| | - Nathalie Beaudoin
- Centre SÈVE, Département de biologie, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada.
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11
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Rakusová H, Han H, Valošek P, Friml J. Genetic screen for factors mediating PIN polarization in gravistimulated Arabidopsis thaliana hypocotyls. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:1048-1059. [PMID: 30821050 PMCID: PMC6618169 DOI: 10.1111/tpj.14301] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 02/13/2019] [Accepted: 02/14/2019] [Indexed: 05/24/2023]
Abstract
Gravitropism is an adaptive response that orients plant growth parallel to the gravity vector. Asymmetric distribution of the phytohormone auxin is a necessary prerequisite to the tropic bending both in roots and shoots. During hypocotyl gravitropic response, the PIN3 auxin transporter polarizes within gravity-sensing cells to redirect intercellular auxin fluxes. First gravity-induced PIN3 polarization to the bottom cell membranes leads to the auxin accumulation at the lower side of the organ, initiating bending and, later, auxin feedback-mediated repolarization restores symmetric auxin distribution to terminate bending. Here, we performed a forward genetic screen to identify regulators of both PIN3 polarization events during gravitropic response. We searched for mutants with defective PIN3 polarizations based on easy-to-score morphological outputs of decreased or increased gravity-induced hypocotyl bending. We identified the number of hypocotyl reduced bending (hrb) and hypocotyl hyperbending (hhb) mutants, revealing that reduced bending correlated typically with defective gravity-induced PIN3 relocation whereas all analyzed hhb mutants showed defects in the second, auxin-mediated PIN3 relocation. Next-generation sequencing-aided mutation mapping identified several candidate genes, including SCARECROW and ACTIN2, revealing roles of endodermis specification and actin cytoskeleton in the respective gravity- and auxin-induced PIN polarization events. The hypocotyl gravitropism screen thus promises to provide novel insights into mechanisms underlying cell polarity and plant adaptive development.
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Affiliation(s)
- Hana Rakusová
- Institute of Science and Technology (IST) Austria3400KlosterneuburgAustria
| | - Huibin Han
- Institute of Science and Technology (IST) Austria3400KlosterneuburgAustria
| | - Petr Valošek
- Institute of Science and Technology (IST) Austria3400KlosterneuburgAustria
| | - Jiří Friml
- Institute of Science and Technology (IST) Austria3400KlosterneuburgAustria
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12
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Kućko A, Wilmowicz E, Ostrowski M. Spatio-temporal IAA gradient is determined by interactions with ET and governs flower abscission. JOURNAL OF PLANT PHYSIOLOGY 2019; 236:51-60. [PMID: 30878877 DOI: 10.1016/j.jplph.2019.02.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 02/10/2019] [Accepted: 02/26/2019] [Indexed: 06/09/2023]
Abstract
The abscission zone (AZ) is a specialized tissue that usually develops at the base of an organ and is highly sensitive to phytohormones, e.g., abscisic acid (ABA), ethylene (ET), and gibberellins (GAs). A current model of organ abscission assumes that the formation of an auxin gradient around the AZ area determines the time of shedding; however, that thesis is supported by studies that are primarily concerned with auxin transporters. To better understand the events underlying the progression of abscission, we focused for the first time on indole-3-acetic acid (IAA) distribution following AZ activation. We performed a series of immunolocalization studies in proximal and distal regions of floral AZ cells in yellow lupine, which is an agriculturally important legume. The examined phytohormone was abundant in natural active AZ cells, as well as above and below parts of this structure. A similar gradient of IAA was observed during the early steps of abscission, which was induced artificially by flower removal. Surprisingly, IAA was not detected in inactive AZ cells. This paper is also a consequence of our comprehensive studies concerning the phytohormonal regulation of flower abscission in yellow lupine. We present new data on interactions between IAA and ET, previously pointed out as a strong modulator of flower separation. The detailed analysis shows that disruption of the natural auxin gradient around the AZ area through the application of synthetic IAA had a positive effect on ET biosynthesis genes. We proved that these changes are accompanied by an accumulation of the ET precursor. On the other hand, exposure to ET significantly affected IAA localization in the whole AZ area in a time-dependent manner. Our results provide insight into the existence of a spatio-temporal sequential pattern of the IAA gradient related to the abscission process; this pattern is maintained by interactions with ET. We present new valuable evidence for the existence of conservative mechanisms that regulate generative organ separation and can help to improve the yield of agronomically significant species in the future.
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Affiliation(s)
- Agata Kućko
- Chair of Plant Physiology and Biotechnology, Nicolaus Copernicus University, 1 LwowskaStreet, 87-100, Toruń, Poland; Chair of Plant Physiology and Biotechnology, University of Gdańsk, 59 Wita Stwosza, 80-308 Gdańsk, Poland.
| | - Emilia Wilmowicz
- Chair of Plant Physiology and Biotechnology, Nicolaus Copernicus University, 1 LwowskaStreet, 87-100, Toruń, Poland.
| | - Maciej Ostrowski
- Department of Biochemistry, Nicolaus Copernicus University, 1 LwowskaStreet, 87-100, Toruń, Poland.
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Ojangu EL, Ilau B, Tanner K, Talts K, Ihoma E, Dolja VV, Paves H, Truve E. Class XI Myosins Contribute to Auxin Response and Senescence-Induced Cell Death in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2018; 9:1570. [PMID: 30538710 PMCID: PMC6277483 DOI: 10.3389/fpls.2018.01570] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 10/08/2018] [Indexed: 05/24/2023]
Abstract
The integrity and dynamics of actin cytoskeleton is necessary not only for plant cell architecture but also for membrane trafficking-mediated processes such as polar auxin transport, senescence, and cell death. In Arabidopsis, the inactivation of actin-based molecular motors, class XI myosins, affects the membrane trafficking and integrity of actin cytoskeleton, and thus causes defective plant growth and morphology, altered lifespan and reduced fertility. To evaluate the potential contribution of class XI myosins to the auxin response, senescence and cell death, we followed the flower and leaf development in the triple gene knockout mutant xi1 xi2 xik (3KO) and in rescued line stably expressing myosin XI-K:YFP (3KOR). Assessing the development of primary inflorescence shoots we found that the 3KO plants produced more axillary branches. Exploiting the auxin-dependent reporters DR5::GUS and IAA2::GUS, a significant reduction in auxin responsiveness was found throughout the development of the 3KO plants. Examination of the flower development of the plants stably expressing the auxin transporter PIN1::PIN1-GFP revealed partial loss of PIN1 polarization in developing 3KO pistils. Surprisingly, the stable expression of PIN1::PIN1-GFP significantly enhanced the semi-sterile phenotype of the 3KO plants. Further we investigated the localization of myosin XI-K:YFP in the 3KOR floral organs and revealed its expression pattern in floral primordia, developing pistils, and anther filaments. Interestingly, the XI-K:YFP and PIN1::PIN1-GFP shared partially overlapping but distinct expression patterns throughout floral development. Assessing the foliar development of the 3KO plants revealed increased rosette leaf production with signs of premature yellowing. Symptoms of the premature senescence correlated with massive loss of chlorophyll, increased cell death, early plasmolysis of epidermal cells, and strong up-regulation of the stress-inducible senescence-associated gene SAG13 in 3KO plants. Simultaneously, the reduced auxin responsiveness and premature leaf senescence were accompanied by significant anthocyanin accumulation in 3KO tissues. Collectively, our results provide genetic evidences that Arabidopsis class XI myosins arrange the flower morphogenesis and leaf longevity via contributing to auxin responses, leaf senescence, and cell death.
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Affiliation(s)
- Eve-Ly Ojangu
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Birger Ilau
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Krista Tanner
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Kristiina Talts
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Eliis Ihoma
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Valerian V. Dolja
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Heiti Paves
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Erkki Truve
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
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14
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Li J, Chen S, Wang X, Shi C, Liu H, Yang J, Shi W, Guo J, Jia H. Hydrogen Sulfide Disturbs Actin Polymerization via S-Sulfhydration Resulting in Stunted Root Hair Growth. PLANT PHYSIOLOGY 2018; 178:936-949. [PMID: 30166418 PMCID: PMC6181039 DOI: 10.1104/pp.18.00838] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 08/21/2018] [Indexed: 05/20/2023]
Abstract
Hydrogen sulfide (H2S) is an important signaling molecule in plants. Our previous report suggested that H2S signaling affects the actin cytoskeleton and root hair growth. However, the underlying mechanisms of its effects are not understood. S-Sulfhydration of proteins is regulated directly by H2S, which converts the thiol groups of cysteine (Cys) residues to persulfides and alters protein function. In this work, we studied the effects of S-sulfhydration on actin dynamics in Arabidopsis (Arabidopsis thaliana). We generated transgenic plants overexpressing the H2S biosynthesis-related genes l-CYSTEINE DESULFHYDRASE (LCD) and d-CYSTEINE DESULFHYDRASE in the O-acetylserine(thiol)lyase isoform a1 (oasa1) mutant and Columbia-0 backgrounds. The H2S content increased significantly in overexpressing LCD/oasa1 plants. The density of filamentous actin (F-actin) bundles and the F-actin/globular actin ratio decreased in overexpressing LCD/oasa1 plants. S-Sulfhydration also was enhanced in overexpressing LCD/oasa1 plants. An analysis of actin dynamics suggested that S-sulfhydration inhibited actin polymerization. We also found that ACTIN2 (ACT2) was S-sulfhydrated at Cys-287. Cys-287 is adjacent to the D-loop, which acts as a central region for hydrophobic and electrostatic interactions and stabilizes F-actin filaments. Overaccumulation of H2S caused the depolymerization of F-actin bundles and inhibited root hair growth. Introduction of ACT2 carrying a Cys-287-to-Ser mutation into an act2-1 mutant partially suppressed H2S-dependent inhibition of root hair growth. We conclude that H2S regulates actin dynamics and affects root hair growth.
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Affiliation(s)
- Jisheng Li
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
- Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Sisi Chen
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xiaofeng Wang
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Cong Shi
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Huaxin Liu
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Jun Yang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Wei Shi
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Junkang Guo
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Honglei Jia
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
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Novak S, Kalbakji N, Upthegrove K, Neher W, Jones J, de León J. Evidence for Brassinosteroid-Mediated PAT During Germination of Spathoglottis plicata (Orchidaceae). FRONTIERS IN PLANT SCIENCE 2018; 9:1215. [PMID: 30174682 PMCID: PMC6107755 DOI: 10.3389/fpls.2018.01215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/30/2018] [Indexed: 05/31/2023]
Abstract
Polar auxin transport (PAT) is facilitated by polar localization of PIN-FORMED (PIN) efflux carriers, which direct auxin flow and regulate developmental events. Brassinosteroids (BRs) and auxin work synergistically to promote growth, and in root geotropisms this cross-talk involves BR-directed polarization of PIN through the mobilization of F-actin. However, the role of BR in PAT during shoot growth, hair formation, and embryogenesis has not been well studied. Orchid seed are mature at a point in development that is analogous to the globular-stage of embryogenesis in typical angiosperms. Thus, this system provided a unique opportunity to study the effects of BR on PAT during embryogenesis-like events, including meristem/first leaf formation and protocorm/stem development, which is followed by protocorm hair formation. In this work, the degree to which BRs rescued embryo-like protocorms from the impact of PAT-disrupting agents, such as PAT inhibitors or high auxin levels, was determined based on growth responses. This study first established that auxin and BRs work together synergistically to promote seedling elongation in Spathoglottis. Repressed seedling growth caused by the PAT-disrupting agents was alleviated with eBL, suggesting that BRs enhance PAT in embryogenesis-like stages of young protocorms. However, similar responses were not evident in seed embryos. Results from this study also suggested that BRs may enhance orchid protocorm elongation by regulating auxin transport through an F-actin-mediated mechanism. With regard to protocorm hairs, increased eBL levels inhibited formation, whereas reduced BR biosynthesis altered hair patterning, and prevented outgrowth of auxin-stimulated hairs. Moreover, PAT inhibitors and repression of BR biosynthesis caused hair bud formation without hair outgrowth, suggesting a role for BR in PAT during protocorm hair development.
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Affiliation(s)
- Stacey Novak
- Department of Biology, University of La Verne, La Verne, CA, United States
| | - Nataly Kalbakji
- Department of Biology, University of La Verne, La Verne, CA, United States
- Southern California College of Optometry at Marshall B. Ketchum, Fullerton, CA, United States
| | - Kylie Upthegrove
- Department of Biology, University of La Verne, La Verne, CA, United States
| | - Wesley Neher
- Department of Biology, University of La Verne, La Verne, CA, United States
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, United States
| | - Jay Jones
- Department of Biology, University of La Verne, La Verne, CA, United States
| | - Jazmin de León
- Department of Biology, University of La Verne, La Verne, CA, United States
- Ross University School of Veterinary Medicine, Saint Kitts, West Indies
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16
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Wang C, Fu D. Virus-Induced Gene Silencing of the Eggplant Chalcone Synthase Gene during Fruit Ripening Modifies Epidermal Cells and Gravitropism. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:2623-2629. [PMID: 29494770 DOI: 10.1021/acs.jafc.7b05617] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Eggplant ( Solanum melongena L.) fruits accumulate flavonoids in their cuticle and epidermal cells during ripening. Although many mutants available in model plant species, such as Arabidopsis thaliana and Medicago truncatula, are enabling the intricacies of flavonoid-related physiology to be deduced, the mechanisms whereby flavonoids influence eggplant fruit physiology are unknown. Virus-induced gene silencing (VIGS) is a reliable tool for the study of flavonoid function in fruit, and in this study, we successfully applied this technique to downregulate S. melongena chalcone synthase gene ( SmCHS) expression during eggplant fruit ripening. In addition to the expected change in fruit color attributable to a lack of anthocyanins, several other modifications, including differences in epidermal cell size and shape, were observed in the different sectors. We also found that silencing of CHS gene expression was associated with a negative gravitropic response in eggplant fruits. These observations indicate that epidermal cell expansion during ripening is dependent upon CHS expression and that there may be a relationship between CHS expression and gravitropism during eggplant fruit ripening.
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Affiliation(s)
- Cuicui Wang
- Fruit Biology Laboratory, College of Food Science and Nutritional Engineering , China Agricultural University , Beijing 100083 , People's Republic of China
| | - Daqi Fu
- Fruit Biology Laboratory, College of Food Science and Nutritional Engineering , China Agricultural University , Beijing 100083 , People's Republic of China
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17
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Arabidopsis vegetative actin isoforms, AtACT2 and AtACT7, generate distinct filament arrays in living plant cells. Sci Rep 2018. [PMID: 29531328 PMCID: PMC5847576 DOI: 10.1038/s41598-018-22707-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Flowering plants express multiple actin isoforms. Previous studies suggest that individual actin isoforms have specific functions; however, the subcellular localization of actin isoforms in plant cells remains obscure. Here, we transiently expressed and observed major Arabidopsis vegetative actin isoforms, AtACT2 and AtACT7, as fluorescent-fusion proteins. By optimizing the linker sequence between fluorescent protein and actin, we succeeded in observing filaments that contained these expressed actin isoforms fused with green fluorescent protein (GFP) in Arabidopsis protoplasts. Different colored fluorescent proteins fused with AtACT2 and AtACT7 and co-expressed in Nicotiana benthamiana mesophyll cells co-polymerized in a segregated manner along filaments. In epidermal cells, surprisingly, AtACT2 and AtACT7 tended to polymerize into different types of filaments. AtACT2 was incorporated into thinner filaments, whereas AtACT7 was incorporated into thick bundles. We conclude that different actin isoforms are capable of constructing unique filament arrays, depending on the cell type or tissue. Interestingly, staining patterns induced by two indirect actin filament probes, Lifeact and mTalin1, were different between filaments containing AtACT2 and those containing AtACT7. We suggest that filaments containing different actin isoforms bind specific actin-binding proteins in vivo, since the two probes comprise actin-binding domains from different actin-binding proteins.
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18
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Paez-Garcia A, Sparks JA, de Bang L, Blancaflor EB. Plant Actin Cytoskeleton: New Functions from Old Scaffold. PLANT CELL MONOGRAPHS 2018. [DOI: 10.1007/978-3-319-69944-8_6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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19
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Huang X, Maisch J, Nick P. Sensory role of actin in auxin-dependent responses of tobacco BY-2. JOURNAL OF PLANT PHYSIOLOGY 2017; 218:6-15. [PMID: 28763708 DOI: 10.1016/j.jplph.2017.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 05/09/2023]
Abstract
Polar auxin transport depends on the polar localization of auxin-efflux carriers. The cycling of these carriers between cell interior and plasma membrane depends on actin. The dynamic of actin not only affects auxin transport, but also changes the auxin-responsiveness. To study the potential link between auxin responsiveness and actin dynamics, we investigated developmental responses of the non-transformed BY-2 (Nicotiana tabacum L. cv Bright Yellow 2) cell line and the transgenic BY-2 strain GF11 (stably transformed BY-2 cells with a GFP-fimbrin actin-binding domain 2 construct). The developmental process was divided into three distinct stages: cell cycling, cell elongation and file disintegration. Several phenotypes were measured to monitor the cellular responses to different concentrations of exogenous natural auxin (Indole-3-acetic acid, IAA). We found that auxin stimulated and prolonged the mitotic activity, and delayed the exit from the proliferation phase. However, both responses were suppressed in the GF11 line. At the stationary phase of the cultivation cycle, auxin strongly accelerated the cell file disintegration. Interestingly, it was not suppressed but progressed to a more complete disintegration in the GF11 line. During the cultivation cycle, we also followed the organization of actin in the GF11 line and did not detect any significant difference in actin organization from untreated control or exogenous IAA treatment. Therefore, our findings indicate that the specific differences observed in the GF11 line must be linked with a function of actin that is not structural. It means that there is a sensory role of actin for auxin signaling.
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Affiliation(s)
- Xiang Huang
- Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg. 4, Gbd. 30.43, (5. OG), 76131 Karlsruhe, Germany.
| | - Jan Maisch
- Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg. 4, Gbd. 30.43, (5. OG), 76131 Karlsruhe, Germany.
| | - Peter Nick
- Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg. 4, Gbd. 30.43, (5. OG), 76131 Karlsruhe, Germany.
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20
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Cheng ML, Lo SF, Hsiao AS, Hong YF, Yu SM, Ho THD. Ectopic Expression of WINDING 1 Leads to Asymmetrical Distribution of Auxin and a Spiral Phenotype in Rice. PLANT & CELL PHYSIOLOGY 2017; 58:1494-1506. [PMID: 28922746 DOI: 10.1093/pcp/pcx088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 06/19/2017] [Indexed: 06/07/2023]
Abstract
Ectopic expression of the rice WINDING 1 (WIN1) gene leads to a spiral phenotype only in shoots but not in roots. Rice WIN1 belongs to a specific class of proteins in cereal plants containing a Bric-a-Brac/Tramtrack/Broad (BTB) complex, a non-phototropic hypocotyl 3 (NPH3) domain and a coiled-coil motif. The WIN1 protein is predominantly localized to the plasma membrane, but is also co-localized to plasmodesmata, where it exhibits a punctate pattern. It is observed that WIN1 is normally expressed in roots and the shoot-root junction, but not in the rest of shoots. In roots, WIN1 is largely localized to the apical and basal sides of cells. However, upon ectopic expression, WIN1 appears on the longitudinal sides of leaf sheath cells, correlated with the appearance of a spiral phenotype in shoots. Despite the spiral phenotype, WIN1-overexpressing plants exhibit a normal phototropic response. Although treatments with exogenous auxins or a polar auxin transport inhibitor do not alter the spiral phenotype, the excurvature side has a higher auxin concentration than the incurvature side. Furthermore, actin filaments are more prominent in the excurvature side than in the incurvature side, which correlates with cell size differences between these two sides. Interestingly, ectopic expression of WIN1 does not cause either unequal auxin distribution or actin filament differences in roots, so a spiral phenotype is not observed in roots. The action of WIN1 appears to be different from that of other proteins causing a spiral phenotype, and it is likely that WIN1 is involved in 1-N-naphthylphthalamic acid-insensitive plasmodesmata-mediated auxin transport.
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Affiliation(s)
- Ming-Lung Cheng
- Department of Life Sciences, National Cheng Kung University, Tainan 701, Taiwan, ROC
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
| | - Shuen-Fang Lo
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
- Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan, ROC
| | - An-Shan Hsiao
- Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
| | - Ya-Fang Hong
- Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
| | - Su-May Yu
- Department of Life Sciences, National Cheng Kung University, Tainan 701, Taiwan, ROC
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
- Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan, ROC
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan, ROC
| | - Tuan-Hua David Ho
- Department of Life Sciences, National Cheng Kung University, Tainan 701, Taiwan, ROC
- Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan, ROC
- Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan, ROC
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21
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Tang LP, Li XM, Dong YX, Zhang XS, Su YH. Microfilament Depolymerization Is a Pre-requisite for Stem Cell Formation During In vitro Shoot Regeneration in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2017; 8:158. [PMID: 28261231 PMCID: PMC5306138 DOI: 10.3389/fpls.2017.00158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 01/25/2017] [Indexed: 05/23/2023]
Abstract
De novo shoot regeneration is widely used in fundamental studies and agricultural applications. Actin microfilaments are involved in many aspects of plant cell division, cell morphogenesis and cell signal transduction. However, the function of actin microfilaments during de novo shoot regeneration is poorly understood. Here, we investigated the organization of actin microfilaments during this process and found that stem cell formation was associated with microfilament depolymerization. Furthermore, inhibition of microfilament depolymerization by phalloidin treatment or downregulation of actin depolymerizing factors (ADFs) restrained stem cell initiation and shoot regeneration. Inhibition of ADF expression affected the architecture of microfilaments during stem cell formation, and the polar transport and distribution of auxin were also disrupted. Together, our results demonstrate that organization of the microfilament cytoskeleton play important roles in stem cell formation and shoot meristem induction during shoot regeneration.
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Affiliation(s)
- Li Ping Tang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural UniversityTaian, China
| | - Xiao Ming Li
- Shandong Provincial Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural UniversityTaian, China
| | - Yu Xiu Dong
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural UniversityTaian, China
| | - Xian Sheng Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural UniversityTaian, China
| | - Ying Hua Su
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural UniversityTaian, China
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22
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Eggenberger K, Sanyal P, Hundt S, Wadhwani P, Ulrich AS, Nick P. Challenge Integrity: The Cell-Penetrating Peptide BP100 Interferes with the Auxin-Actin Oscillator. PLANT & CELL PHYSIOLOGY 2017; 58:71-85. [PMID: 28173585 DOI: 10.1093/pcp/pcw161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 09/12/2016] [Indexed: 05/12/2023]
Abstract
Actin filaments are essential for the integrity of the cell membrane. In addition to this structural role, actin can modulate signaling by altering polar auxin flow. On the other hand, the organization of actin filaments is modulated by auxin constituting a self-referring signaling hub. Although the function of this auxin–actin oscillator is not clear, there is evidence for a functional link with stress signaling activated by the NADPH oxidase Respiratory burst oxidase Homolog (RboH). In the current work, we used the cell-penetrating peptide BP100 to induce a mild and transient perturbation of membrane integrity. We followed the response of actin to the BP100 uptake in a green fluorescent protein (GFP)-tagged actin marker line of tobacco Bright Yellow 2 (BY-2) cells by spinning disc confocal microscopy. We observed that BP100 enters in a stepwise manner and reduces the extent of actin remodeling. This actin ‘freezing’ can be rescued by the natural auxin IAA, and mimicked by the auxin-efflux inhibitor 1-napthylphthalamic acid (NPA). We further tested the role of the membrane-localized NADPH oxidase RboH using the specific inhibitor diphenyl iodonium (DPI), and found that DPI acts antagonistically to BP100, although DPI alone can induce a similar actin ‘freezing’ as well. We propose a working model, where the mild violation of membrane integrity by BP100 stimulates RboH, and the resulting elevated levels of reactive oxygen species interfere with actin dynamicity. The mitigating effect of auxin is explained by competition of auxin- and RboH-triggered signaling for superoxide anions. This self-referring auxin–actin–RboH hub might be essential for integrity sensing.
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Affiliation(s)
- Kai Eggenberger
- Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr, Karlsruhe, Germany
| | - Papia Sanyal
- Institute of Biological Interfaces (IBG-2) and DFG-Center of Functional Nanostructures (CFN), Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber Weg 6, Karlsruhe, Germany
| | - Svenja Hundt
- Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr, Karlsruhe, Germany
| | - Parvesh Wadhwani
- Institute of Biological Interfaces (IBG-2) and DFG-Center of Functional Nanostructures (CFN), Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber Weg 6, Karlsruhe, Germany
| | - Anne S Ulrich
- Institute of Biological Interfaces (IBG-2) and DFG-Center of Functional Nanostructures (CFN), Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber Weg 6, Karlsruhe, Germany
| | - Peter Nick
- Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr, Karlsruhe, Germany
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23
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Sandalio LM, Rodríguez-Serrano M, Romero-Puertas MC. Leaf epinasty and auxin: A biochemical and molecular overview. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 253:187-193. [PMID: 27968987 DOI: 10.1016/j.plantsci.2016.10.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 10/03/2016] [Accepted: 10/05/2016] [Indexed: 05/16/2023]
Abstract
Leaf epinasty involves the downward bending of leaves as a result of disturbances in their growth, with a greater expansion in adaxial cells as compared to abaxial surface cells. The co-ordinated anisotropy of growth in epidermal, palisade mesophyll and vascular tissues contributes to epinasty. This phenotype, which is regulated by auxin (indole-3-acetic acid, IAA), controls plant cell division and elongation by regulating the expression of a vast number of genes. Other plant hormones, such as ethylene, abscisic acid and brassinosteroids, also regulate epinasty and hyponasty. Reactive oxygen species (ROS) accumulation induced by auxins and 2,4-dichlorophenoxyacetic acid (2,4-D) triggers epinasty. The role of ROS and nitric oxide (NO) in the regulation of epinasty has recently been established. Thus, treatment with synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) induces disturbances in the actin cytoskeleton through ROS and NO-dependent post-translational modifications in actin by carbonylation and S-nitrosylation, which cause a reduction in the actin filament. Reorientation of microtubules has become a major feature of the response to auxin. The cytoskeleton is therefore a key player in epinastic development.
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Affiliation(s)
- Luisa M Sandalio
- Department of Biochemistry and Molecular and Cellular Biology of Plants, Estación Experimental del Zaidín, CSIC, Profesor Albareda 1, 18008, Granada, Spain.
| | - María Rodríguez-Serrano
- Department of Biochemistry and Molecular and Cellular Biology of Plants, Estación Experimental del Zaidín, CSIC, Profesor Albareda 1, 18008, Granada, Spain
| | - María C Romero-Puertas
- Department of Biochemistry and Molecular and Cellular Biology of Plants, Estación Experimental del Zaidín, CSIC, Profesor Albareda 1, 18008, Granada, Spain
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24
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Kühn N, Serrano A, Abello C, Arce A, Espinoza C, Gouthu S, Deluc L, Arce-Johnson P. Regulation of polar auxin transport in grapevine fruitlets (Vitis vinifera L.) and the proposed role of auxin homeostasis during fruit abscission. BMC PLANT BIOLOGY 2016; 16:234. [PMID: 27793088 PMCID: PMC5084367 DOI: 10.1186/s12870-016-0914-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 10/04/2016] [Indexed: 05/05/2023]
Abstract
BACKGROUND Indole-3-acetic acid (IAA), the most abundant auxin, is a growth promoter hormone involved in several developmental processes. Auxin homeostasis is very important to its function and this is achieved through the regulation of IAA biosynthesis, conjugation, degradation and transport. In grapevine, IAA plays an essential role during initial stages of berry development, since it delays fruitlet abscission by reducing the ethylene sensitivity in the abscission zone. For this reason, Continuous polar IAA transport to the pedicel is required. This kind of transport is controlled by IAA, which regulates its own movement by modifying the expression and localization of PIN-FORMED (PIN) auxin efflux facilitators that localize asymmetrically within the cell. On the other hand, the hormone gibberellin (GA) also activates the polar auxin transport by increasing PIN stability. In Vitis vinifera, fruitlet abscission occurs during the first two to three weeks after flowering. During this time, IAA and GA are present, however the role of these hormones in the control of polar auxin transport is unknown. RESULTS In this work, the use of radiolabeled IAA showed that auxin is basipetally transported during grapevine fruitlet abscission. This observation was further supported by immunolocalization of putative VvPIN proteins that display a basipetal distribution in pericarp cells. Polar auxin transport and transcripts of four putative VvPIN genes decreased in conjunction with increased abscission, and the inhibition of polar auxin transport resulted in fruit drop. GA3 and IAA treatments reduced polar auxin transport, but only GA3 treatment decreased VvPIN transcript abundance. When GA biosynthesis was blocked, IAA was capable to increase polar auxin transport, suggesting that its effect depends on GA content. Finally, we observed significant changes in the content of several IAA-related compounds during the abscission period. CONCLUSIONS These results provide evidence that auxin homeostasis plays a central role during grapevine initial fruit development and that GA and IAA controls auxin homeostasis by reducing polar auxin transport.
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Affiliation(s)
- Nathalie Kühn
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Alameda 340, PO Box 114-D, Santiago, Chile
| | - Alejandra Serrano
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Alameda 340, PO Box 114-D, Santiago, Chile
| | - Carlos Abello
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Alameda 340, PO Box 114-D, Santiago, Chile
| | - Aníbal Arce
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Alameda 340, PO Box 114-D, Santiago, Chile
| | - Carmen Espinoza
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Alameda 340, PO Box 114-D, Santiago, Chile
| | | | - Laurent Deluc
- Department of Horticulture, Oregon State University, Corvallis, OR 97331 USA
| | - Patricio Arce-Johnson
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Alameda 340, PO Box 114-D, Santiago, Chile
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25
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Kovaleva LV, Voronkov AS, Zakharova EV, Minkina YV, Timofeeva GV, Andreev IM. Exogenous IAA and ABA stimulate germination of petunia male gametophyte by activating Ca2+-dependent K+-channels and by modulating the activity of plasmalemma H+-ATPase and actin cytoskeleton. Russ J Dev Biol 2016. [DOI: 10.1134/s1062360416030036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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26
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Madmon O, Mazuz M, Kumari P, Dam A, Ion A, Mayzlish-Gati E, Belausov E, Wininger S, Abu-Abied M, McErlean CSP, Bromhead LJ, Perl-Treves R, Prandi C, Kapulnik Y, Koltai H. Expression of MAX2 under SCARECROW promoter enhances the strigolactone/MAX2 dependent response of Arabidopsis roots to low-phosphate conditions. PLANTA 2016; 243:1419-1427. [PMID: 26919985 DOI: 10.1007/s00425-016-2477-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 01/22/2016] [Indexed: 06/05/2023]
Abstract
MAX2/strigolactone signaling in the endodermis and/or quiescent center of the root is partially sufficient to exert changes in F-actin density and cellular trafficking in the root epidermis, and alter gene expression during plant response to low Pi conditions. Strigolactones (SLs) are a new group of plant hormones that regulate different developmental processes in the plant via MAX2, an F-box protein that interacts with their receptor. SLs and MAX2 are necessary for the marked increase in root-hair (RH) density in seedlings under conditions of phosphate (Pi) deprivation. This marked elevation was associated with an active reduction in actin-filament density and endosomal movement in root epidermal cells. Also, expression of MAX2 under the SCARECROW (SCR) promoter was sufficient to confer SL sensitivity in roots, suggesting that SL signaling pathways act through a root-specific, yet non-cell-autonomous regulatory mode of action. Here we show evidence for a non-cell autonomous signaling of SL/MAX2, originating from the root endodermis, and necessary for seedling response to conditions of Pi deprivation. SCR-derived expression of MAX2 in max2-1 mutant background promoted the root low Pi response, whereas supplementation of the synthetic SL GR24 to these SCR:MAX2 expressing lines further enhanced this response. Moreover, the SCR:MAX2 expression led to changes in actin density and endosome movement in epidermal cells and in TIR1 and PHO2 gene expression. These results demonstrate that MAX2 signaling in the endodermis and/or quiescent center is partially sufficient to exert changes in F-actin density and cellular trafficking in the epidermis, and alter gene expression under low Pi conditions.
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Affiliation(s)
- Ortal Madmon
- Institute of Plant Sciences, Agricultural Research Organization (ARO), The Volcani Center, 50250, Bet Dagan, Israel
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, 52900, Ramat-Gan, Israel
| | - Moran Mazuz
- Institute of Plant Sciences, Agricultural Research Organization (ARO), The Volcani Center, 50250, Bet Dagan, Israel
| | - Puja Kumari
- Institute of Plant Sciences, Agricultural Research Organization (ARO), The Volcani Center, 50250, Bet Dagan, Israel
| | - Anandamoy Dam
- Institute of Plant Sciences, Agricultural Research Organization (ARO), The Volcani Center, 50250, Bet Dagan, Israel
| | - Aurel Ion
- Institute of Plant Sciences, Agricultural Research Organization (ARO), The Volcani Center, 50250, Bet Dagan, Israel
| | - Einav Mayzlish-Gati
- Institute of Plant Sciences, Agricultural Research Organization (ARO), The Volcani Center, 50250, Bet Dagan, Israel
| | - Eduard Belausov
- Institute of Plant Sciences, Agricultural Research Organization (ARO), The Volcani Center, 50250, Bet Dagan, Israel
| | - Smadar Wininger
- Institute of Plant Sciences, Agricultural Research Organization (ARO), The Volcani Center, 50250, Bet Dagan, Israel
| | - Mohamad Abu-Abied
- Institute of Plant Sciences, Agricultural Research Organization (ARO), The Volcani Center, 50250, Bet Dagan, Israel
| | | | - Liam J Bromhead
- School of Chemistry, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Rafael Perl-Treves
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, 52900, Ramat-Gan, Israel
| | - Cristina Prandi
- Dipartimento di Chimica, Turin University, 10125, Turin, Italy
| | - Yoram Kapulnik
- Institute of Plant Sciences, Agricultural Research Organization (ARO), The Volcani Center, 50250, Bet Dagan, Israel
| | - Hinanit Koltai
- Institute of Plant Sciences, Agricultural Research Organization (ARO), The Volcani Center, 50250, Bet Dagan, Israel.
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27
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Zhu J, Bailly A, Zwiewka M, Sovero V, Di Donato M, Ge P, Oehri J, Aryal B, Hao P, Linnert M, Burgardt NI, Lücke C, Weiwad M, Michel M, Weiergräber OH, Pollmann S, Azzarello E, Mancuso S, Ferro N, Fukao Y, Hoffmann C, Wedlich-Söldner R, Friml J, Thomas C, Geisler M. TWISTED DWARF1 Mediates the Action of Auxin Transport Inhibitors on Actin Cytoskeleton Dynamics. THE PLANT CELL 2016; 28:930-48. [PMID: 27053424 PMCID: PMC4863381 DOI: 10.1105/tpc.15.00726] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 03/21/2016] [Accepted: 04/05/2016] [Indexed: 05/18/2023]
Abstract
Plant growth and architecture is regulated by the polar distribution of the hormone auxin. Polarity and flexibility of this process is provided by constant cycling of auxin transporter vesicles along actin filaments, coordinated by a positive auxin-actin feedback loop. Both polar auxin transport and vesicle cycling are inhibited by synthetic auxin transport inhibitors, such as 1-N-naphthylphthalamic acid (NPA), counteracting the effect of auxin; however, underlying targets and mechanisms are unclear. Using NMR, we map the NPA binding surface on the Arabidopsis thaliana ABCB chaperone TWISTED DWARF1 (TWD1). We identify ACTIN7 as a relevant, although likely indirect, TWD1 interactor, and show TWD1-dependent regulation of actin filament organization and dynamics and that TWD1 is required for NPA-mediated actin cytoskeleton remodeling. The TWD1-ACTIN7 axis controls plasma membrane presence of efflux transporters, and as a consequence act7 and twd1 share developmental and physiological phenotypes indicative of defects in auxin transport. These can be phenocopied by NPA treatment or by chemical actin (de)stabilization. We provide evidence that TWD1 determines downstream locations of auxin efflux transporters by adjusting actin filament debundling and dynamizing processes and mediating NPA action on the latter. This function appears to be evolutionary conserved since TWD1 expression in budding yeast alters actin polarization and cell polarity and provides NPA sensitivity.
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Affiliation(s)
- Jinsheng Zhu
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Aurelien Bailly
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland Department of Plant and Microbial Biology, University of Zurich, CH-8008 Zurich, Switzerland
| | - Marta Zwiewka
- CEITEC-Central European Institute of Technology, Masaryk University, CZ-625 00 Brno, Czech Republic
| | - Valpuri Sovero
- Department of Plant and Microbial Biology, University of Zurich, CH-8008 Zurich, Switzerland
| | - Martin Di Donato
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Pei Ge
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Jacqueline Oehri
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland Institute of Evolutionary Biology and Environmental Studies, University of Zurich, CH-8057 Zurich, Switzerland
| | - Bibek Aryal
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Pengchao Hao
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Miriam Linnert
- Max Planck Research Unit for Enzymology of Protein Folding, D-06099 Halle (Saale), Germany
| | - Noelia Inés Burgardt
- Max Planck Research Unit for Enzymology of Protein Folding, D-06099 Halle (Saale), Germany Institute of Biochemistry and Biophysics (IQUIFIB), School of Pharmacy and Biochemistry, University of Buenos Aires, C1113AAD Buenos Aires, Argentina
| | - Christian Lücke
- Max Planck Research Unit for Enzymology of Protein Folding, D-06099 Halle (Saale), Germany
| | - Matthias Weiwad
- Max Planck Research Unit for Enzymology of Protein Folding, D-06099 Halle (Saale), Germany Department of Enzymology, Martin-Luther-University Halle-Wittenberg, Institute of Biochemistry and Biotechnology, D-06099 Halle, Germany
| | - Max Michel
- Institute of Complex Systems, ICS-6: Structural Biochemistry, D-52425 Jülich, Germany
| | - Oliver H Weiergräber
- Institute of Complex Systems, ICS-6: Structural Biochemistry, D-52425 Jülich, Germany
| | - Stephan Pollmann
- Centro de Biotecnología y Genómica de Plantas, 28223 Pozuelo de Alarcón, Madrid, Spain
| | | | | | - Noel Ferro
- University of Bonn, Mulliken Center for Theoretical Chemistry, Institute for Physical and Theoretical Chemistry, D-53115 Bonn, Germany
| | - Yoichiro Fukao
- Plant Global Educational Project, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
| | - Céline Hoffmann
- Cytoskeleton and Cancer Progression, Laboratory of Experimental Cancer Research, Department of Oncology, Luxembourg Institute of Health, L-1526 Luxembourg, Luxembourg
| | | | - Jiří Friml
- Institute of Science and Technology Austria, A-3400 Klosterneuburg, Austria
| | - Clément Thomas
- Cytoskeleton and Cancer Progression, Laboratory of Experimental Cancer Research, Department of Oncology, Luxembourg Institute of Health, L-1526 Luxembourg, Luxembourg
| | - Markus Geisler
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland Department of Plant and Microbial Biology, University of Zurich, CH-8008 Zurich, Switzerland
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28
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Scheuring D, Löfke C, Krüger F, Kittelmann M, Eisa A, Hughes L, Smith RS, Hawes C, Schumacher K, Kleine-Vehn J. Actin-dependent vacuolar occupancy of the cell determines auxin-induced growth repression. Proc Natl Acad Sci U S A 2016; 113:452-7. [PMID: 26715743 PMCID: PMC4720293 DOI: 10.1073/pnas.1517445113] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The cytoskeleton is an early attribute of cellular life, and its main components are composed of conserved proteins. The actin cytoskeleton has a direct impact on the control of cell size in animal cells, but its mechanistic contribution to cellular growth in plants remains largely elusive. Here, we reveal a role of actin in regulating cell size in plants. The actin cytoskeleton shows proximity to vacuoles, and the phytohormone auxin not only controls the organization of actin filaments but also impacts vacuolar morphogenesis in an actin-dependent manner. Pharmacological and genetic interference with the actin-myosin system abolishes the effect of auxin on vacuoles and thus disrupts its negative influence on cellular growth. SEM-based 3D nanometer-resolution imaging of the vacuoles revealed that auxin controls the constriction and luminal size of the vacuole. We show that this actin-dependent mechanism controls the relative vacuolar occupancy of the cell, thus suggesting an unanticipated mechanism for cytosol homeostasis during cellular growth.
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Affiliation(s)
- David Scheuring
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Christian Löfke
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Falco Krüger
- Center for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Maike Kittelmann
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
| | - Ahmed Eisa
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Louise Hughes
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
| | - Richard S Smith
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Chris Hawes
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
| | - Karin Schumacher
- Center for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Jürgen Kleine-Vehn
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria;
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29
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Chen HW, Shao KH, Wang SJ. Light-modulated seminal wavy roots in rice mediated by nitric oxide-dependent signaling. PROTOPLASMA 2015; 252:1291-1304. [PMID: 25619895 DOI: 10.1007/s00709-015-0762-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 01/12/2015] [Indexed: 06/04/2023]
Abstract
Rice (Oryza sativa L.) seminal roots from germinated seeds help establish seedlings, but the seminal root growth and morphology are sensitive to environmental factors. Our previous research showed that several indica-type rice varieties such as Taichung native 1 (TCN1) showed light-induced wavy roots. Also, auxin and oxylipins are two signaling factors regulating the wavy root photomorphology. To investigate the signaling pathway, here, we found that nitric oxide (NO) was a second messenger triggering the signal transduction of light stimuli to induce the wavy morphology of seminal roots in rice. Moreover, interactions between oxylipins and phytohormones such as ethylene and auxin participating in the NO-dependent regulatory pathway of light-induced wavy roots were examined. The order of action of signaling components in the pathway was NO, oxylipins, ethylene, and auxin.
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Affiliation(s)
- Hsiang-Wen Chen
- Department of Agronomy, National Taiwan University, No. 1, Section 4, Roosevelt Rd., Taipei, 10617, Taiwan
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30
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Pesacreta TC. F-actin distribution in root primary tissues of several seed plant species. AMERICAN JOURNAL OF BOTANY 2015; 102:1422-1433. [PMID: 26391707 DOI: 10.3732/ajb.1500179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 08/13/2015] [Indexed: 06/05/2023]
Abstract
PREMISE OF THE STUDY Primary vascular tissues of angiosperm and gymnosperm roots have significant anatomical differences. In gymnosperms, lack of protophloem sieve elements indicates a lengthy parenchymatous pathway for nutrient transport to the root apical meristem (RAM). Because F-actin is an essential component of transport in parenchyma cells, the distribution of F-actin was determined and compared among roots of several angiosperm and gymnosperm species. METHODS Roots were chemically fixed and sectioned by hand to enable rapid production of many sections for labeling F-actin with phalloidin. KEY RESULTS In angiosperm and gymnosperm root tips, relative intensity of F-actin labeling was highest in primary vascular tissues. Parenchyma cells in and around protophloem tended to have more F-actin while cells in cortical and protoxylem tissues tended to have less. In gymnosperms, phloem parenchyma was intensely labeled for several millimeters distal to the root apical meristem (RAM), and the F-actin is mostly composed of bundles that lie parallel to the root longitudinal axis. This orientation differed from the multidirectional arrangement of F-actin filaments in cortical cells. In angiosperms, intense F-actin labeling of pericycle and phloem parenchyma cells occurred around the first mature sieve elements. CONCLUSIONS F-actin is concentrated in the vascular cylinder, commonly in primary phloem parenchyma. In gymnosperms, the absence of sieve elements suggests that cytoplasmic streaming has a role in some aspect of phloem transport or unloading. In angiosperms, the region of intense F-actin labeling in the phloem parenchyma is limited to the extreme terminal portion of primary phloem where unloading of the earliest mature sieve elements occurs.
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Affiliation(s)
- Thomas C Pesacreta
- Microscopy Center, University of Louisiana Lafayette, P.O. Box 42451, Lafayette, Louisiana 70504 USA
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31
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Activation of Big Grain1 significantly improves grain size by regulating auxin transport in rice. Proc Natl Acad Sci U S A 2015; 112:11102-7. [PMID: 26283354 DOI: 10.1073/pnas.1512748112] [Citation(s) in RCA: 202] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Grain size is one of the key factors determining grain yield. However, it remains largely unknown how grain size is regulated by developmental signals. Here, we report the identification and characterization of a dominant mutant big grain1 (Bg1-D) that shows an extra-large grain phenotype from our rice T-DNA insertion population. Overexpression of BG1 leads to significantly increased grain size, and the severe lines exhibit obviously perturbed gravitropism. In addition, the mutant has increased sensitivities to both auxin and N-1-naphthylphthalamic acid, an auxin transport inhibitor, whereas knockdown of BG1 results in decreased sensitivities and smaller grains. Moreover, BG1 is specifically induced by auxin treatment, preferentially expresses in the vascular tissue of culms and young panicles, and encodes a novel membrane-localized protein, strongly suggesting its role in regulating auxin transport. Consistent with this finding, the mutant has increased auxin basipetal transport and altered auxin distribution, whereas the knockdown plants have decreased auxin transport. Manipulation of BG1 in both rice and Arabidopsis can enhance plant biomass, seed weight, and yield. Taking these data together, we identify a novel positive regulator of auxin response and transport in a crop plant and demonstrate its role in regulating grain size, thus illuminating a new strategy to improve plant productivity.
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32
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Koltai H. Cellular events of strigolactone signalling and their crosstalk with auxin in roots. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4855-61. [PMID: 25900617 DOI: 10.1093/jxb/erv178] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Strigolactones are a new group of plant hormones that suppress shoot branching. In roots, they regulate primary-root growth and lateral-root formation and increase root-hair elongation. Reception of strigolactones occurs via a specific cellular system which includes a D14-like/MAX2-like/SCF complex that, upon perception of strigolactone signalling, leads to certain degradation of receptors and to the release of downstream targets. This signalling pathway may eventually result in changes in actin-filament bundling, cellular trafficking, and PIN localization in the plasma membrane. As a result, auxin flux may be regulated in the shoot or root. Strigolactones are also involved with the response to phosphate conditions in roots, acting by both dampening auxin transport via depletion of PIN2 from the plasma membrane and inducing TIR1 transcription to increase auxin perception. In these instances and, possibly, others, strigolactones manipulate the auxin pathway, affecting its transport, perception or both. However, other mechanisms for strigolactone-regulated plant development and the involvement of other plant hormones are evident.
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Affiliation(s)
- Hinanit Koltai
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Israel
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33
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Zhu J, Geisler M. Keeping it all together: auxin-actin crosstalk in plant development. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4983-98. [PMID: 26085676 DOI: 10.1093/jxb/erv308] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Polar auxin transport and the action of the actin cytoskeleton are tightly interconnected, which is documented by the finding that auxin transporters reach their final destination by active movement of secretory vesicles along F-actin tracks. Moreover, auxin transporter polarity and flexibility is thought to depend on transporter cycling that requires endocytosis and exocytosis of vesicles. In this context, we have reviewed the current literature on an involvement of the actin cytoskeleton in polar auxin transport and identify known similarities and differences in its structure, function and dynamics in comparison to non-plant organisms. By describing how auxin modulates actin expression and actin organization and how actin and its stability affects auxin-transporter endocytosis and recycling, we discuss the current knowledge on regulatory auxin-actin feedback loops. We focus on known effects of auxin and of auxin transport inhibitors on the stability and organization of actin and examine the functionality of auxin and/or auxin transport inhibitor-binding proteins with respect to their suitability to integrate auxin/auxin transport inhibitor action. Finally, we indicate current difficulties in the interpretation of organ, time and concentration-dependent auxin/auxin transport inhibitor treatments and formulate simple future experimental guidelines.
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Affiliation(s)
- Jinsheng Zhu
- University of Fribourg, Department of Biology-Plant Biology, CH-1700 Fribourg, Switzerland
| | - Markus Geisler
- University of Fribourg, Department of Biology-Plant Biology, CH-1700 Fribourg, Switzerland
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34
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Straltsova D, Chykun P, Subramaniam S, Sosan A, Kolbanov D, Sokolik A, Demidchik V. Cation channels are involved in brassinosteroid signalling in higher plants. Steroids 2015; 97:98-106. [PMID: 25449770 DOI: 10.1016/j.steroids.2014.10.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 10/06/2014] [Accepted: 10/21/2014] [Indexed: 11/27/2022]
Abstract
Brassinosteroids (BRs) are an important class of plant hormones with a multitude of functions. They have been intensively investigated for their biosynthesis, distribution and physiological functions. The aim of this study was to examine possible effects of BRs on the plant plasma membrane cation conductances and Ca(2+) signalling. The wheat root protoplasts (tested by patch-clamping) and excised arabidopsis roots (analysed by Ca(2+)-aequorin chemiluminometry), were used. In the whole-cell plasma membrane patches, 24-epibrassinolide, 28-homobrassionolide or 24-epicastasterone (1 μM) were applied exogenously. 24-Epicastasterone increased the activity of the K(+) efflux conductance in 50% of tested protoplasts while 24-epibrassonolide and 28-homobrassionolide did not modify the plasma membrane currents. Addition of 24-epicastasterone at the cytosolic side (to the pipette solution) resulted in dramatic stimulation of a time-dependent K(+) efflux current (in 30% of protoplasts) and an activation of Ca(2+) influx currents (in 30% of protoplasts). Gadolinium ions, which are blockers of cation channels, inhibited the 24-epicastasterone-induced cation channel activities. In Arabidopsis thaliana plants constitutively expressing aequorin, exogenous 24-epibrassonolide, 28-homobrassionolide and 24-epicastasterone induced a transient elevation of the cytosolic free Ca(2+), which was inhibited by Gd(3+) and mediated by Ca(2+) influx from the bathing solution. In Ca(2+)-aequorin tests, 10 μM of exogenous BRs was the minimal concentration at which statistically significant changes of the cytosolic Ca(2+) were observed. In conclusion, the obtained results suggest that the plasma membrane of root cells contains the brassinosteroid-activated cation-permeable channels, which can probably be involved in rapid regulation of the K(+) homeostasis and Ca(2+) signalling.
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Affiliation(s)
- Darya Straltsova
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Ave., Minsk 220030, Belarus.
| | - Palina Chykun
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Ave., Minsk 220030, Belarus.
| | - Sunitha Subramaniam
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, United Kingdom.
| | - Arifa Sosan
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, United Kingdom.
| | - Dmitriy Kolbanov
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Ave., Minsk 220030, Belarus.
| | - Anatoliy Sokolik
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Ave., Minsk 220030, Belarus.
| | - Vadim Demidchik
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Ave., Minsk 220030, Belarus.
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Actin as deathly switch? How auxin can suppress cell-death related defence. PLoS One 2015; 10:e0125498. [PMID: 25933033 PMCID: PMC4416736 DOI: 10.1371/journal.pone.0125498] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 03/17/2015] [Indexed: 11/19/2022] Open
Abstract
Plant innate immunity is composed of two layers--a basal immunity, and a specific effector-triggered immunity, which is often accompanied by hypersensitive cell death. Initiation of cell death depends on a complex network of signalling pathways. The phytohormone auxin as central regulator of plant growth and development represents an important component for the modulation of plant defence. In our previous work, we showed that cell death is heralded by detachment of actin from the membrane. Both, actin response and cell death, are triggered by the bacterial elicitor harpin in grapevine cells. In this study we investigated, whether harpin-triggered actin bundling is necessary for harpin-triggered cell death. Since actin organisation is dependent upon auxin, we used different auxins to suppress actin bundling. Extracellular alkalinisation and transcription of defence genes as the basal immunity were examined as well as cell death. Furthermore, organisation of actin was observed in response to pharmacological manipulation of reactive oxygen species and phospholipase D. We find that induction of defence genes is independent of auxin. However, auxin can suppress harpin-induced cell death and also counteract actin bundling. We integrate our findings into a model, where harpin interferes with an auxin dependent pathway that sustains dynamic cortical actin through the activity of phospholipase D. The antagonism between growth and defence is explained by mutual competition for signal molecules such as superoxide and phosphatidic acid. Perturbations of the auxin-actin pathway might be used to detect disturbed integrity of the plasma membrane and channel defence signalling towards programmed cell death.
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Kumar M, Pandya-Kumar N, Dam A, Haor H, Mayzlish-Gati E, Belausov E, Wininger S, Abu-Abied M, McErlean CSP, Bromhead LJ, Prandi C, Kapulnik Y, Koltai H. Arabidopsis response to low-phosphate conditions includes active changes in actin filaments and PIN2 polarization and is dependent on strigolactone signalling. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:1499-510. [PMID: 25609825 PMCID: PMC4339606 DOI: 10.1093/jxb/eru513] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Strigolactones (SLs) are plant hormones that regulate the plant response to phosphate (Pi) growth conditions. At least part of SL-signalling execution in roots involves MAX2-dependent effects on PIN2 polar localization in the plasma membrane (PM) and actin bundling and dynamics. We examined PIN2 expression, PIN2 PM localization, endosome trafficking, and actin bundling under low-Pi conditions: a MAX2-dependent reduction in PIN2 trafficking and polarization in the PM, reduced endosome trafficking, and increased actin-filament bundling were detected in root cells. The intracellular protein trafficking that is related to PIN proteins but unassociated with AUX1 PM localization was selectively inhibited. Exogenous supplementation of the synthetic SL GR24 to a SL-deficient mutant (max4) led to depletion of PIN2 from the PM under low-Pi conditions. Accordingly, roots of mutants in MAX2, MAX4, PIN2, TIR3, and ACTIN2 showed a reduced low-Pi response compared with the wild type, which could be restored by auxin (for all mutants) or GR24 (for all mutants except max2-1). Changes in PIN2 polarity, actin bundling, and vesicle trafficking may be involved in the response to low Pi in roots, dependent on SL/MAX2 signalling.
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Affiliation(s)
- Manoj Kumar
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan 50250, Israel
| | - Nirali Pandya-Kumar
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan 50250, Israel
| | - Anandamoy Dam
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan 50250, Israel
| | - Hila Haor
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan 50250, Israel
| | - Einav Mayzlish-Gati
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan 50250, Israel
| | - Eduard Belausov
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan 50250, Israel
| | - Smadar Wininger
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan 50250, Israel
| | - Mohamad Abu-Abied
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan 50250, Israel
| | | | - Liam J Bromhead
- School of Chemistry, the University of Sydney, NSW 2006, Australia
| | - Cristina Prandi
- Dipartimento di Chimica, Turin University, 10125 Torino, Italy
| | - Yoram Kapulnik
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan 50250, Israel
| | - Hinanit Koltai
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan 50250, Israel
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Kumar M, Pandya-Kumar N, Kapulnik Y, Koltai H. Strigolactone signaling in root development and phosphate starvation. PLANT SIGNALING & BEHAVIOR 2015; 10:e1045174. [PMID: 26251884 PMCID: PMC4622057 DOI: 10.1080/15592324.2015.1045174] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 04/22/2015] [Indexed: 05/22/2023]
Abstract
Strigolactones (SLs), have recently been recognized as phytohormone involve in orchestrating shoot and root architecture. In, roots SLs positively regulate root hair length and density, suppress lateral root formation and promote primary root meristem cell number. The biosynthesis and exudation of SLs increases under low phosphate level to regulate root responses. This hormonal response suggests an adaptation strategy of plant to optimize growth and development under nutrient limitations. However, little is known on signal-transduction pathways associated with SL activities. In this review, we outline the current knowledge on SL biology by describing their role in the regulation of root development. Also, we discuss the recent findings on the non-cell autonomous signaling of SLs, that involve PIN polarization, vesicle trafficking, changes in actin architecture and dynamic in response to phosphate starvation.
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Affiliation(s)
- Manoj Kumar
- Institute of Plant Sciences; Agricultural Research Organization (ARO); the Volcani Center; Bet Dagan, Israel
- Current address: Plant Functional Biology and Climate Change Cluster (C3); University of Technology Sydney (UTS); Sydney, Australia
- Correspondence to: Manoj Kumar;
| | - Nirali Pandya-Kumar
- Institute of Plant Sciences; Agricultural Research Organization (ARO); the Volcani Center; Bet Dagan, Israel
| | - Yoram Kapulnik
- Institute of Plant Sciences; Agricultural Research Organization (ARO); the Volcani Center; Bet Dagan, Israel
| | - Hinanit Koltai
- Institute of Plant Sciences; Agricultural Research Organization (ARO); the Volcani Center; Bet Dagan, Israel
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38
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Ruan Y, Wasteneys GO. CLASP: a microtubule-based integrator of the hormone-mediated transitions from cell division to elongation. CURRENT OPINION IN PLANT BIOLOGY 2014; 22:149-158. [PMID: 25460080 DOI: 10.1016/j.pbi.2014.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Revised: 10/18/2014] [Accepted: 11/01/2014] [Indexed: 05/17/2023]
Abstract
Plants use robust mechanisms to optimize organ size to prevailing conditions. Modulating the transition from cell division to elongation dramatically affects morphology and size. Although it is well established that auxin, cytokinin and brassinosteroid mediate these transitions, recent works show that the cytoskeleton, which is normally thought to act downstream of these hormones, plays a key role in this regulatory process. In particular, the microtubule-associated protein CLASP has a dual role in meristem maintenance. CLASP modulates levels of the auxin efflux carrier PIN2 by tethering SNX1 endosomes to cortical microtubules, which in turn fine tunes auxin maxima in the root apical meristem. CLASP is also required for transfacial microtubule bundle formation at the sharp cell edges, a feature strongly associated with maintaining the capacity for further cell division.
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Affiliation(s)
- Yuan Ruan
- The University of British Columbia, Department of Botany, 6270 University Blvd, Vancouver, BC V6T 1Z4, Canada
| | - Geoffrey O Wasteneys
- The University of British Columbia, Department of Botany, 6270 University Blvd, Vancouver, BC V6T 1Z4, Canada.
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39
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Kühn N, Abello C, Godoy F, Delrot S, Arce-Johnson P. Differential behavior within a grapevine cluster: decreased ethylene-related gene expression dependent on auxin transport is correlated with low abscission of first developed berries. PLoS One 2014; 9:e111258. [PMID: 25365421 PMCID: PMC4218718 DOI: 10.1371/journal.pone.0111258] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 09/22/2014] [Indexed: 11/20/2022] Open
Abstract
In grapevine, fruit abscission is known to occur within the first two to three weeks after flowering, but the reason why some berries in a cluster persist and others abscise is not yet understood. Ethylene sensitivity modulates abscission in several fruit species, based on a mechanism where continuous polar auxin transport across the pedicel results in a decrease in ethylene perception, which prevents abscission. In grapevine, flowering takes about four to seven days in a single cluster, thus while some flowers are developing into berries, others are just starting to open. So, in this work it was assessed whether uneven flowering accounted for differences in berry abscission dependent on polar auxin transport and ethylene-related gene expression. For this, flowers that opened in a cluster were tagged daily, which allowed to separately analyze berries, regarding their ability to persist. It was found that berries derived from flowers that opened the day that flowering started – named as “first berries” – had lower abscission rate than berries derived from flowers that opened during the following days – named as “late berries”. Use of radiolabeled auxin showed that “first berries” had higher polar auxin transport, correlated with lower ethylene content and lower ethylene-related transcript abundance than “late berries”. When “first berries” were treated with a polar auxin transport inhibitor they showed higher ethylene-related transcript abundance and were more prone to abscise than control berries. This study provides new insights on fruit abscission control. Our results indicate that polar auxin transport sustains the ability of “first berries” to persist in the cluster during grapevine abscission and also suggest that this could be associated with changes in ethylene-related gene expression.
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Affiliation(s)
- Nathalie Kühn
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carlos Abello
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Francisca Godoy
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Serge Delrot
- Université de Bordeaux, ISVV, INRA, EGFV, UMR 1287, Villenave d'Ornon, France
| | - Patricio Arce-Johnson
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, Chile
- * E-mail:
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40
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Koltai H. Receptors, repressors, PINs: a playground for strigolactone signaling. TRENDS IN PLANT SCIENCE 2014; 19:727-33. [PMID: 25037847 DOI: 10.1016/j.tplants.2014.06.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/13/2014] [Accepted: 06/20/2014] [Indexed: 05/20/2023]
Abstract
Strigolactones, previously identified as active stimuli of seed germination in parasitic plants, are now recognized as a new group of plant hormones that are active in both shoots and roots. Here, we review recent insights into the concepts of strigolactones-signal transduction and their mode of action. Although strigolactones are sensed via a cell-specific reception system, at least some aspects of their activity are conducted in a non-cell-autonomous fashion. Strigolactones also affect trafficking and plasma-membrane localization of the auxin transporter PIN, thereby regulating auxin flux. We present a model for strigolactone-signal transduction that might also explain the integration of strigolactones into other hormone-signaling pathways via the regulation of PIN auxin transporters.
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Affiliation(s)
- Hinanit Koltai
- Institute of Plant Sciences, ARO, Volcani Center, Bet-Dagan 50250, Israel.
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41
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Rodríguez-Serrano M, Pazmiño DM, Sparkes I, Rochetti A, Hawes C, Romero-Puertas MC, Sandalio LM. 2,4-Dichlorophenoxyacetic acid promotes S-nitrosylation and oxidation of actin affecting cytoskeleton and peroxisomal dynamics. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:4783-93. [PMID: 24913628 PMCID: PMC4144765 DOI: 10.1093/jxb/eru237] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
2,4-Dichlorophenoxyacetic acid (2,4-D) is a synthetic auxin used as a herbicide to control weeds in agriculture. A high concentration of 2,4-D promotes leaf epinasty and cell death. In this work, the molecular mechanisms involved in the toxicity of this herbicide are studied by analysing in Arabidopsis plants the accumulation of reactive oxygen species (ROS) and nitric oxide (NO), and their effect on cytoskeleton structure and peroxisome dynamics. 2,4-D (23 mM) promotes leaf epinasty, whereas this process was prevented by EDTA, which can reduce ·OH accumulation. The analysis of ROS accumulation by confocal microscopy showed a 2,4-D-dependent increase in both H2O2 and O2·(-), whereas total NO was not affected by the treatment. The herbicide promotes disturbances on the actin cytoskeleton structure as a result of post-translational modification of actin by oxidation and S-nitrosylation, which could disturb actin polymerization, as suggested by the reduction of the F-actin/G-actin ratio. These effects were reduced by EDTA, and the reduction of ROS production in Arabidopsis mutants deficient in xanthine dehydrogenase (Atxdh) gave rise to a reduction in actin oxidation. Also, 2,4-D alters the dynamics of the peroxisome, slowing the speed and shortening the distances by which these organelles are displaced. It is concluded that 2,4-D promotes oxidative and nitrosative stress, causing disturbances in the actin cytoskeleton, thereby affecting the dynamics of peroxisomes and some other organelles such as the mitochondria, with xanthine dehydrogenase being involved in ROS production under these conditions. These structural changes in turn appear to be responsible for the leaf epinasty.
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Affiliation(s)
- M Rodríguez-Serrano
- Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidín, CSIC, Apartado 419, 18080 Granada, Spain
| | - D M Pazmiño
- Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidín, CSIC, Apartado 419, 18080 Granada, Spain
| | - I Sparkes
- School of Biological & Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - A Rochetti
- School of Biological & Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - C Hawes
- School of Biological & Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - M C Romero-Puertas
- Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidín, CSIC, Apartado 419, 18080 Granada, Spain
| | - L M Sandalio
- Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidín, CSIC, Apartado 419, 18080 Granada, Spain
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42
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Etemadi M, Gutjahr C, Couzigou JM, Zouine M, Lauressergues D, Timmers A, Audran C, Bouzayen M, Bécard G, Combier JP. Auxin perception is required for arbuscule development in arbuscular mycorrhizal symbiosis. PLANT PHYSIOLOGY 2014; 166:281-92. [PMID: 25096975 PMCID: PMC4149713 DOI: 10.1104/pp.114.246595] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 08/04/2014] [Indexed: 05/02/2023]
Abstract
Most land plant species live in symbiosis with arbuscular mycorrhizal fungi. These fungi differentiate essential functional structures called arbuscules in root cortical cells from which mineral nutrients are released to the plant. We investigated the role of microRNA393 (miR393), an miRNA that targets several auxin receptors, in arbuscular mycorrhizal root colonization. Expression of the precursors of the miR393 was down-regulated during mycorrhization in three different plant species: Solanum lycopersicum, Medicago truncatula, and Oryza sativa. Treatment of S. lycopersicum, M. truncatula, and O. sativa roots with concentrations of synthetic auxin analogs that did not affect root development stimulated mycorrhization, particularly arbuscule formation. DR5-GUS, a reporter for auxin response, was preferentially expressed in root cells containing arbuscules. Finally, overexpression of miR393 in root tissues resulted in down-regulation of auxin receptor genes (transport inhibitor response1 and auxin-related F box) and underdeveloped arbuscules in all three plant species. These results support the conclusion that miR393 is a negative regulator of arbuscule formation by hampering auxin perception in arbuscule-containing cells.
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Affiliation(s)
- Mohammad Etemadi
- Université Paul Sabatier Toulouse, Unité Mixte de Recherche 5546, Laboratoire de Recherche en Sciences Végétales, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5546, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Institut National Polytechnique-Ecole Nationale Supérieure Agronomique Toulouse, Génomique et Biotechnologie des Fruits, F-31326 Castanet-Tolosan, France (M.E., M.Z., C.A., M.B.);Institut National de la Recherche Agronomique, Génomique et Biotechnologie des Fruits, F-52627 Auzeville, France (M.E., M.Z., C.A., M.B.);Faculty of Biology, Genetics, University of Munich, 82152 Martinsried, Germany (C.G.); andLaboratoire des Interactions Plantes-Microorganismes, Unité Mixte de Recherche 441/2594 Institut National de la Recherche Agronomique-Centre National de la Recherche Scientifique, F-31326 Castanet-Tolosan cedex, France (A.T.)
| | - Caroline Gutjahr
- Université Paul Sabatier Toulouse, Unité Mixte de Recherche 5546, Laboratoire de Recherche en Sciences Végétales, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5546, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Institut National Polytechnique-Ecole Nationale Supérieure Agronomique Toulouse, Génomique et Biotechnologie des Fruits, F-31326 Castanet-Tolosan, France (M.E., M.Z., C.A., M.B.);Institut National de la Recherche Agronomique, Génomique et Biotechnologie des Fruits, F-52627 Auzeville, France (M.E., M.Z., C.A., M.B.);Faculty of Biology, Genetics, University of Munich, 82152 Martinsried, Germany (C.G.); andLaboratoire des Interactions Plantes-Microorganismes, Unité Mixte de Recherche 441/2594 Institut National de la Recherche Agronomique-Centre National de la Recherche Scientifique, F-31326 Castanet-Tolosan cedex, France (A.T.)
| | - Jean-Malo Couzigou
- Université Paul Sabatier Toulouse, Unité Mixte de Recherche 5546, Laboratoire de Recherche en Sciences Végétales, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5546, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Institut National Polytechnique-Ecole Nationale Supérieure Agronomique Toulouse, Génomique et Biotechnologie des Fruits, F-31326 Castanet-Tolosan, France (M.E., M.Z., C.A., M.B.);Institut National de la Recherche Agronomique, Génomique et Biotechnologie des Fruits, F-52627 Auzeville, France (M.E., M.Z., C.A., M.B.);Faculty of Biology, Genetics, University of Munich, 82152 Martinsried, Germany (C.G.); andLaboratoire des Interactions Plantes-Microorganismes, Unité Mixte de Recherche 441/2594 Institut National de la Recherche Agronomique-Centre National de la Recherche Scientifique, F-31326 Castanet-Tolosan cedex, France (A.T.)
| | - Mohamed Zouine
- Université Paul Sabatier Toulouse, Unité Mixte de Recherche 5546, Laboratoire de Recherche en Sciences Végétales, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5546, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Institut National Polytechnique-Ecole Nationale Supérieure Agronomique Toulouse, Génomique et Biotechnologie des Fruits, F-31326 Castanet-Tolosan, France (M.E., M.Z., C.A., M.B.);Institut National de la Recherche Agronomique, Génomique et Biotechnologie des Fruits, F-52627 Auzeville, France (M.E., M.Z., C.A., M.B.);Faculty of Biology, Genetics, University of Munich, 82152 Martinsried, Germany (C.G.); andLaboratoire des Interactions Plantes-Microorganismes, Unité Mixte de Recherche 441/2594 Institut National de la Recherche Agronomique-Centre National de la Recherche Scientifique, F-31326 Castanet-Tolosan cedex, France (A.T.)
| | - Dominique Lauressergues
- Université Paul Sabatier Toulouse, Unité Mixte de Recherche 5546, Laboratoire de Recherche en Sciences Végétales, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5546, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Institut National Polytechnique-Ecole Nationale Supérieure Agronomique Toulouse, Génomique et Biotechnologie des Fruits, F-31326 Castanet-Tolosan, France (M.E., M.Z., C.A., M.B.);Institut National de la Recherche Agronomique, Génomique et Biotechnologie des Fruits, F-52627 Auzeville, France (M.E., M.Z., C.A., M.B.);Faculty of Biology, Genetics, University of Munich, 82152 Martinsried, Germany (C.G.); andLaboratoire des Interactions Plantes-Microorganismes, Unité Mixte de Recherche 441/2594 Institut National de la Recherche Agronomique-Centre National de la Recherche Scientifique, F-31326 Castanet-Tolosan cedex, France (A.T.)
| | - Antonius Timmers
- Université Paul Sabatier Toulouse, Unité Mixte de Recherche 5546, Laboratoire de Recherche en Sciences Végétales, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5546, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Institut National Polytechnique-Ecole Nationale Supérieure Agronomique Toulouse, Génomique et Biotechnologie des Fruits, F-31326 Castanet-Tolosan, France (M.E., M.Z., C.A., M.B.);Institut National de la Recherche Agronomique, Génomique et Biotechnologie des Fruits, F-52627 Auzeville, France (M.E., M.Z., C.A., M.B.);Faculty of Biology, Genetics, University of Munich, 82152 Martinsried, Germany (C.G.); andLaboratoire des Interactions Plantes-Microorganismes, Unité Mixte de Recherche 441/2594 Institut National de la Recherche Agronomique-Centre National de la Recherche Scientifique, F-31326 Castanet-Tolosan cedex, France (A.T.)
| | - Corinne Audran
- Université Paul Sabatier Toulouse, Unité Mixte de Recherche 5546, Laboratoire de Recherche en Sciences Végétales, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5546, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Institut National Polytechnique-Ecole Nationale Supérieure Agronomique Toulouse, Génomique et Biotechnologie des Fruits, F-31326 Castanet-Tolosan, France (M.E., M.Z., C.A., M.B.);Institut National de la Recherche Agronomique, Génomique et Biotechnologie des Fruits, F-52627 Auzeville, France (M.E., M.Z., C.A., M.B.);Faculty of Biology, Genetics, University of Munich, 82152 Martinsried, Germany (C.G.); andLaboratoire des Interactions Plantes-Microorganismes, Unité Mixte de Recherche 441/2594 Institut National de la Recherche Agronomique-Centre National de la Recherche Scientifique, F-31326 Castanet-Tolosan cedex, France (A.T.)
| | - Mondher Bouzayen
- Université Paul Sabatier Toulouse, Unité Mixte de Recherche 5546, Laboratoire de Recherche en Sciences Végétales, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5546, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Institut National Polytechnique-Ecole Nationale Supérieure Agronomique Toulouse, Génomique et Biotechnologie des Fruits, F-31326 Castanet-Tolosan, France (M.E., M.Z., C.A., M.B.);Institut National de la Recherche Agronomique, Génomique et Biotechnologie des Fruits, F-52627 Auzeville, France (M.E., M.Z., C.A., M.B.);Faculty of Biology, Genetics, University of Munich, 82152 Martinsried, Germany (C.G.); andLaboratoire des Interactions Plantes-Microorganismes, Unité Mixte de Recherche 441/2594 Institut National de la Recherche Agronomique-Centre National de la Recherche Scientifique, F-31326 Castanet-Tolosan cedex, France (A.T.)
| | - Guillaume Bécard
- Université Paul Sabatier Toulouse, Unité Mixte de Recherche 5546, Laboratoire de Recherche en Sciences Végétales, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5546, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Institut National Polytechnique-Ecole Nationale Supérieure Agronomique Toulouse, Génomique et Biotechnologie des Fruits, F-31326 Castanet-Tolosan, France (M.E., M.Z., C.A., M.B.);Institut National de la Recherche Agronomique, Génomique et Biotechnologie des Fruits, F-52627 Auzeville, France (M.E., M.Z., C.A., M.B.);Faculty of Biology, Genetics, University of Munich, 82152 Martinsried, Germany (C.G.); andLaboratoire des Interactions Plantes-Microorganismes, Unité Mixte de Recherche 441/2594 Institut National de la Recherche Agronomique-Centre National de la Recherche Scientifique, F-31326 Castanet-Tolosan cedex, France (A.T.)
| | - Jean-Philippe Combier
- Université Paul Sabatier Toulouse, Unité Mixte de Recherche 5546, Laboratoire de Recherche en Sciences Végétales, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5546, F-31326 Castanet-Tolosan cedex, France (M.E., J.-M.C., D.L., G.B., J.-P.C.);Institut National Polytechnique-Ecole Nationale Supérieure Agronomique Toulouse, Génomique et Biotechnologie des Fruits, F-31326 Castanet-Tolosan, France (M.E., M.Z., C.A., M.B.);Institut National de la Recherche Agronomique, Génomique et Biotechnologie des Fruits, F-52627 Auzeville, France (M.E., M.Z., C.A., M.B.);Faculty of Biology, Genetics, University of Munich, 82152 Martinsried, Germany (C.G.); andLaboratoire des Interactions Plantes-Microorganismes, Unité Mixte de Recherche 441/2594 Institut National de la Recherche Agronomique-Centre National de la Recherche Scientifique, F-31326 Castanet-Tolosan cedex, France (A.T.)
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Guan X, Buchholz G, Nick P. Actin marker lines in grapevine reveal a gatekeeper function of guard cells. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:1164-1173. [PMID: 24973589 DOI: 10.1016/j.jplph.2014.03.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Revised: 01/26/2014] [Accepted: 03/11/2014] [Indexed: 06/03/2023]
Abstract
Resistance to abiotic and biotic stress is a central topic for sustainable agriculture, especially in grapevine, one of the field crops with the highest economic output per acreage. As early cellular factors for plant defense, actin microfilaments (AF) are of high relevance. We therefore generated a transgenic actin marker line for grapevine by expressing a fusion protein between green fluorescent protein and the second actin-binding domain of Arabidopsis (Arabidopsis thaliana) fimbrin, AtFIM1. Based on this first cytoskeletal-marker line in grapevine, the response of AFs to phytopathogenic microorganisms could be followed in vivo. Upon inoculation with fluorescently labeled strains of phytopathogenic bacteria, actin responses were confined to the guard cells. In contrast, upon contact with zoospores of Plasmopara viticola, not only the guard cells, but also epidermal pavement cells, where no zoospores had attached responded with the formation of a perinuclear actin basket. Our data support the hypothesis that guard cells act as pacemakers of defense, dominating the responses of the remaining epidermal cells.
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Affiliation(s)
- Xin Guan
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstraße 2, D-76128 Karlsruhe, Germany; College of Horticulture and Landscape Architecture, Southwest University, 400716 Chongqing, China.
| | - Günther Buchholz
- RLP AgroScience/AlPlanta - Institute for Plant Research, Breitenweg 71, D-67435 Neustadt an der Weinstraße, Germany
| | - Peter Nick
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstraße 2, D-76128 Karlsruhe, Germany
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44
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Gutjahr C. Phytohormone signaling in arbuscular mycorhiza development. CURRENT OPINION IN PLANT BIOLOGY 2014; 20:26-34. [PMID: 24853646 DOI: 10.1016/j.pbi.2014.04.003] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/15/2014] [Accepted: 04/17/2014] [Indexed: 05/20/2023]
Abstract
To establish arbuscular mycorhiza (AM) symbiosis glomeromycotan fungi colonize the interior of roots. This process is associated with developmental changes of root cells as well as fungal hyphae. The formation of fungal colonization-structures and the extent of root colonization are largely under plant control, depending on environmental conditions and the resulting physiological state of the host. Phytohormone signaling pathways are currently emerging as important regulators of AM development. Root exuded strigolactones activate AM fungi before colonization and a host strigolactone receptor component is required for AM development. Auxin quantitatively influences AM colonization and might perform an additional cell-autonomous function in the promotion of arbuscule development. Gibberellin signaling inhibits AM and conversely DELLA proteins are required for AM formation. Given the importance of phytohormone signaling in plant developmental responses to the environment it can be predicted that elucidating how phytohormones regulate AM development will provide a lead into understanding how plants orchestrate AM symbiosis with their physiological needs under changing environmental conditions.
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Affiliation(s)
- Caroline Gutjahr
- Faculty of Biology, Genetics, University of Munich (LMU), Großhaderner Str. 2-4, 82152 Martinsried, Germany.
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45
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Zaban B, Liu W, Jiang X, Nick P. Plant cells use auxin efflux to explore geometry. Sci Rep 2014; 4:5852. [PMID: 25068254 PMCID: PMC5376164 DOI: 10.1038/srep05852] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 07/08/2014] [Indexed: 12/24/2022] Open
Abstract
Cell movement is the central mechanism for animal morphogenesis. Plant cell development rather relies on flexible alignment of cell axis adjusting cellular differentiation to directional cues. As central input, vectorial fields of mechanical stress and gradients of the phytohormone auxin have been discussed. In tissue contexts, mechanical and chemical signals will always act in concert; experimentally it is difficult to dissect their individual roles. We have designed a novel approach, based on cells, where directionality has been eliminated by removal of the cell wall. We impose a new axis using a microfluidic set-up to generate auxin gradients. Rectangular microvessels are integrated orthogonally with the gradient. Cells in these microvessels align their new axis with microvessel geometry before touching the wall. Auxin efflux is necessary for this touch-independent geometry exploration and we suggest a model, where auxin gradients can be used to align cell axis in tissues with minimized mechanical tensions.
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Affiliation(s)
- Beatrix Zaban
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstr. 2, D-76128 Karlsruhe, Germany
| | - Wenwen Liu
- CAS Key Lab for Biological Effects of Nanomaterials and Nanosafety, National Center for NanoScience and Technology, 11 Beiyitiao, ZhongGuanCun, Beijing, China
| | - Xingyu Jiang
- CAS Key Lab for Biological Effects of Nanomaterials and Nanosafety, National Center for NanoScience and Technology, 11 Beiyitiao, ZhongGuanCun, Beijing, China
| | - Peter Nick
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstr. 2, D-76128 Karlsruhe, Germany
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46
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Singh M, Gupta A, Laxmi A. Glucose control of root growth direction in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2981-93. [PMID: 24719453 PMCID: PMC4071822 DOI: 10.1093/jxb/eru146] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Directional growth of roots is a complex process that is modulated by various environmental signals. This work shows that presence of glucose (Glc) in the medium also extensively modulated seedling root growth direction. Glc modulation of root growth direction was dramatically enhanced by simultaneous brassinosteroid (BR) application. Glc enhanced BR receptor BRASSINOSTEROID INSENSITIVE1 (BRI1) endocytosis from plasma membrane to early endosomes. Glc-induced root deviation was highly enhanced in a PP2A-defective mutant, roots curl in naphthyl phthalamic acid 1-1 (rcn1-1) suggesting that there is a role of phosphatase in Glc-induced root-growth deviation. RCN1, therefore, acted as a link between Glc and the BR-signalling pathway. Polar auxin transport worked further downstream to BR in controlling Glc-induced root deviation response. Glc also affected other root directional responses such as root waving and coiling leading to altered root architecture. High light intensity mimicked the Glc-induced changes in root architecture that were highly reduced in Glc-signalling mutants. Thus, under natural environmental conditions, changing light flux in the environment may lead to enhanced Glc production/response and is a way to manipulate root architecture for optimized development via integrating several extrinsic and intrinsic signalling cues.
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Affiliation(s)
- Manjul Singh
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Aditi Gupta
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Ashverya Laxmi
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
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Rice actin-binding protein RMD is a key link in the auxin-actin regulatory loop that controls cell growth. Proc Natl Acad Sci U S A 2014; 111:10377-82. [PMID: 24982173 DOI: 10.1073/pnas.1401680111] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The plant hormone auxin plays a central role in plant growth and development. Auxin transport and signaling depend on actin organization. Despite its functional importance, the mechanistic link between actin filaments (F-actin) and auxin intracellular signaling remains unclear. Here, we report that the actin-organizing protein Rice Morphology Determinant (RMD), a type II formin from rice (Oryza sativa), provides a key link. Mutants lacking RMD display abnormal cell growth and altered configuration of F-actin array direction. The rmd mutants also exhibit an inhibition of auxin-mediated cell elongation, decreased polar auxin transport, altered auxin distribution gradients in root tips, and suppression of plasma membrane localization of auxin transporters O. sativa PIN-FORMED 1b (OsPIN1b) and OsPIN2 in root cells. We demonstrate that RMD is required for endocytosis, exocytosis, and auxin-mediated OsPIN2 recycling to the plasma membrane. Moreover, RMD expression is directly regulated by heterodimerized O. sativa auxin response factor 23 (OsARF23) and OsARF24, providing evidence that auxin modulates the orientation of F-actin arrays through RMD. In support of this regulatory loop, osarf23 and lines with reduced expression of both OsARF23 and OsARF24 display reduced RMD expression, disrupted F-actin organization and cell growth, less sensitivity to auxin response, and altered auxin distribution and OsPIN localization. Our findings establish RMD as a crucial component of the auxin-actin self-organizing regulatory loop from the nucleus to cytoplasm that controls rice cell growth and morphogenesis.
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Pandya-Kumar N, Shema R, Kumar M, Mayzlish-Gati E, Levy D, Zemach H, Belausov E, Wininger S, Abu-Abied M, Kapulnik Y, Koltai H. Strigolactone analog GR24 triggers changes in PIN2 polarity, vesicle trafficking and actin filament architecture. THE NEW PHYTOLOGIST 2014; 202:1184-1196. [PMID: 24571327 DOI: 10.1111/nph.12744] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 01/16/2014] [Indexed: 05/08/2023]
Abstract
Strigolactones (SLs) are plant hormones that regulate shoot and root development in a MAX2-dependent manner. The mechanism underlying SLs' effects on roots is unclear. We used root hair elongation to measure root response to SLs. We examined the effects of GR24 (a synthetic, biologically active SL analog) on localization of the auxin efflux transporter PIN2, endosomal trafficking, and F-actin architecture and dynamics in the plasma membrane (PM) of epidermal cells of the primary root elongation zone in wildtype (WT) Arabidopsis and the SL-insensitive mutant max2. We also recorded the response to GR24 of trafficking (tir3), actin (der1) and PIN2 (eir1) mutants. GR24 increased polar localization of PIN2 in the PM of epidermal cells and accumulation of PIN2-containing brefeldin A (BFA) bodies, increased ARA7-labeled endosomal trafficking, reduced F-actin bundling and enhanced actin dynamics, all in a MAX2-dependent manner. Most of the der1 and tir3 mutant lines also displayed reduced sensitivity to GR24 with respect to root hair elongation. We suggest that SLs increase PIN2 polar localization, PIN2 endocytosis, endosomal trafficking, actin debundling and actin dynamics in a MAX2-dependent fashion. This enhancement might underlie the WT root's response to SLs, and suggests noncell autonomous activity of SLs in roots.
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Affiliation(s)
- Nirali Pandya-Kumar
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, 50250, Israel
| | - Rony Shema
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, 50250, Israel
- The Robert H. Smith Faculty of Agriculture Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Manoj Kumar
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, 50250, Israel
| | - Einav Mayzlish-Gati
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, 50250, Israel
| | - Danny Levy
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, 50250, Israel
| | - Hanita Zemach
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, 50250, Israel
| | - Eduard Belausov
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, 50250, Israel
| | - Smadar Wininger
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, 50250, Israel
| | - Mohamad Abu-Abied
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, 50250, Israel
| | - Yoram Kapulnik
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, 50250, Israel
| | - Hinanit Koltai
- Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, 50250, Israel
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49
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Vondráková Z, Eliášová K, Vágner M. The anti-actin drugs latrunculin and cytochalasin affect the maturation of spruce somatic embryos in different ways. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 221-222:90-9. [PMID: 24656339 DOI: 10.1016/j.plantsci.2014.02.006] [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] [Received: 11/15/2013] [Revised: 01/24/2014] [Accepted: 02/19/2014] [Indexed: 05/13/2023]
Abstract
The role of the actin cytoskeleton in somatic embryo development was investigated using latrunculin B and cytochalasin D. Brief treatments (1h) with either drug at the start of maturation fragmented the actin in suspensor cells and/or depolymerized actin filaments in meristematic cells. The drugs targeted different cells: latB primarily affected the suspensor cells, but cchD damaged both suspensor and meristematic cells. Lethal damage to the meristematic and suspensor cells was observed when the drugs were applied throughout the maturation period, although the severity of this effect depended on their concentrations. The drugs' effects on the yield of mature somatic embryos were investigated by applying them to embryo cultures throughout the maturation period or for one week at three different points in the maturation process: immediately prior to the start of maturation, during the first week of maturation, and during the fourth week of maturation. The strongest effects were observed when the drugs were applied at the start of maturation. Under these conditions, latB destroyed the suspensors, eliminating the underdeveloped embryos that depend on them. This accelerated the development of embryos that were capable of separating from the suspensors. Thus, while the total number of embryos at the end of the maturation period was lower than in untreated control cultures, the surviving mature embryos were of high quality. cchD treatment at the start of maturation strongly inhibited embryo development. Drug treatment at the end of the maturation period did not significantly affect embryo development: latB caused no change in the yield of somatic embryos, but cchD treatment increased the number of malformed embryos compared to untreated controls.
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Affiliation(s)
- Zuzana Vondráková
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojová 263, CZ-16502 Prague 6, Czech Republic
| | - Kateřina Eliášová
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojová 263, CZ-16502 Prague 6, Czech Republic
| | - Martin Vágner
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojová 263, CZ-16502 Prague 6, Czech Republic.
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50
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Hoffmann C, Moes D, Dieterle M, Neumann K, Moreau F, Tavares Furtado A, Dumas D, Steinmetz A, Thomas C. Live cell imaging reveals actin-cytoskeleton-induced self-association of the actin-bundling protein WLIM1. J Cell Sci 2014; 127:583-98. [PMID: 24284066 DOI: 10.1242/jcs.134536] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Crosslinking of actin filaments into bundles is essential for the assembly and stabilization of specific cytoskeletal structures. However, relatively little is known about the molecular mechanisms underlying actin bundle formation. The two LIM-domain-containing proteins define a novel and evolutionarily conserved family of actin-bundling proteins whose actin-binding and -crosslinking activities primarily rely on their LIM domains. Using TIRF microscopy, we describe real-time formation of actin bundles induced by tobacco NtWLIM1 in vitro. We show that NtWLIM1 binds to single filaments and subsequently promotes their interaction and zippering into tight bundles of mixed polarity. NtWLIM1-induced bundles grew by both elongation of internal filaments and addition of preformed fragments at their extremities. Importantly, these data are highly consistent with the modes of bundle formation and growth observed in transgenic Arabidopsis plants expressing a GFP-fused Arabidopsis AtWLIM1 protein. Using two complementary live cell imaging approaches, a close relationship between NtWLIM1 subcellular localization and self-association was established. Indeed, both BiFC and FLIM-FRET data revealed that, although unstable NtWLIM1 complexes can sporadically form in the cytosol, stable complexes concentrate along the actin cytoskeleton. Remarkably, disruption of the actin cytoskeleton significantly impaired self-association of NtWLIM1. In addition, biochemical analyses support the idea that F-actin facilitates the switch of purified recombinant NtWLIM1 from a monomeric to a di- or oligomeric state. On the basis of our data, we propose a model in which actin binding promotes the formation and stabilization of NtWLIM1 complexes, which in turn might drive the crosslinking of actin filaments.
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Affiliation(s)
- Céline Hoffmann
- Centre de Recherche Public-Santé, 84 Val Fleuri, L-1526 Luxembourg, Luxembourg
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