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Zhang S, de Boer AH, van Duijn B. Auxin effects on ion transport in Chara corallina. JOURNAL OF PLANT PHYSIOLOGY 2016; 193:37-44. [PMID: 26943501 DOI: 10.1016/j.jplph.2016.02.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 02/17/2016] [Accepted: 02/18/2016] [Indexed: 05/26/2023]
Abstract
The plant hormone auxin has been widely studied with regard to synthesis, transport, signaling and functions among the land plants while there is still a lack of knowledge about the possible role for auxin regulation mechanisms in algae with "plant-like" structures. Here we use the alga Chara corallina as a model to study aspects of auxin signaling. In this respect we measured auxin on membrane potential changes and different ion fluxes (K(+), H(+)) through the plasma membrane. Results showed that auxin, mainly IAA, could hyperpolarize the membrane potential of C. corallina internodal cells. Ion flux measurements showed that the auxin-induced membrane potential change may be based on the change of K(+) permeability and/or channel activity rather than through the activation of proton pumps as known in land plants.
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Affiliation(s)
- Suyun Zhang
- Plant Biodynamics Laboratory, Institute Biology Leiden, Leiden University, Sylvius Laboratory, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Albertus H de Boer
- Department of Structural Biology, Faculty Earth and Life Sciences, Vrije Universiteit, De Boelelaan 1085-1087, 1081HV Amsterdam, The Netherlands
| | - Bert van Duijn
- Plant Biodynamics Laboratory, Institute Biology Leiden, Leiden University, Sylvius Laboratory, Sylviusweg 72, 2333 BE Leiden, The Netherlands; Fytagoras, Sylvius Laboratory, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
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2
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Pielot R, Kohl S, Manz B, Rutten T, Weier D, Tarkowská D, Rolčík J, Strnad M, Volke F, Weber H, Weschke W. Hormone-mediated growth dynamics of the barley pericarp as revealed by magnetic resonance imaging and transcript profiling. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:6927-43. [PMID: 26276866 PMCID: PMC4623697 DOI: 10.1093/jxb/erv397] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The shape of the maternal pericarp affects cereal grain mass and yield. Pericarp growth was analysed by magnetic resonance imaging (MRI), revealing topological maps of mobile water in developing pericarp of barley (Hordeum vulgare) and displaying tissue regions actively elongating in specific temporal-spatial patterns. Correlation analysis of MRI signals and growth rates reveals that growth in length is mediated by dorsal and also lateral rather than ventral regions. Growth in thickness is related to ventral regions. Switching from dorsal to ventral growth is associated with differential expression of axial regulators of the HD-ZipIII and Kanadi/Ettin types, and NPH3 photoreceptors, suggesting light-mediated auxin re-distribution. Auxin increases with the highest levels in the basal pericarp at 6 days after fertilization (DAF), together with transcriptionally up-regulated auxin transport and signalling. Gibberellin biosynthesis is transcriptionally up-regulated only later, and levels of bioactive gibberellins increase from 7 to 13 DAF, with higher levels in ventral than dorsal regions. Differential gene expression related to cell expansion indicates genes related to apoplast acidification, wall relaxation, sugar cleavage, water transport, and cell wall biosynthesis. Candidate genes potentially involved in pericarp extension are distinguished by their temporal expression, representing potential isoforms responsible for dorsal-mediated early growth in length or ventral-mediated late growth in thickness.
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Affiliation(s)
- Rainer Pielot
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung, D-06466 Gatersleben, Germany
| | - Stefan Kohl
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung, D-06466 Gatersleben, Germany
| | - Bertram Manz
- Fraunhofer Institut für Biomedizinische Technik (IBMT) Simulation, Visualization & Magnetic Resonance, Ensheimer Str. 48, D-66386 St. Ingbert, Germany
| | - Twan Rutten
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung, D-06466 Gatersleben, Germany
| | - Diana Weier
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung, D-06466 Gatersleben, Germany
| | - Danuše Tarkowská
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR and Palacký University, Šlechtitelů 11, CZ-78371, Olomouc, Czech Republic
| | - Jakub Rolčík
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR and Palacký University, Šlechtitelů 11, CZ-78371, Olomouc, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR and Palacký University, Šlechtitelů 11, CZ-78371, Olomouc, Czech Republic
| | - Frank Volke
- Fraunhofer Institut für Biomedizinische Technik (IBMT) Simulation, Visualization & Magnetic Resonance, Ensheimer Str. 48, D-66386 St. Ingbert, Germany
| | - Hans Weber
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung, D-06466 Gatersleben, Germany
| | - Winfriede Weschke
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung, D-06466 Gatersleben, Germany
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Anschütz U, Becker D, Shabala S. Going beyond nutrition: regulation of potassium homoeostasis as a common denominator of plant adaptive responses to environment. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:670-87. [PMID: 24635902 DOI: 10.1016/j.jplph.2014.01.009] [Citation(s) in RCA: 230] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 01/14/2014] [Accepted: 01/17/2014] [Indexed: 05/18/2023]
Abstract
Partially and fully completed plant genome sequencing projects in both lower and higher plants allow drawing a comprehensive picture of the molecular and structural diversities of plant potassium transporter genes and their encoded proteins. While the early focus of the research in this field was aimed on the structure-function studies and understanding of the molecular mechanisms underlying K(+) transport, availability of Arabidopsis thaliana mutant collections in combination with micro-array techniques have significantly advanced our understanding of K(+) channel physiology, providing novel insights into the transcriptional regulation of potassium homeostasis in plants. More recently, posttranslational regulation of potassium transport systems has moved into the center stage of potassium transport research. The current review is focused on the most exciting developments in this field. By summarizing recent work on potassium transporter regulation we show that potassium transport in general, and potassium channels in particular, represent important targets and are mediators of the cellular responses during different developmental stages in a plant's life cycle. We show that regulation of intracellular K(+) homeostasis is essential to mediate plant adaptive responses to a broad range of abiotic and biotic stresses including drought, salinity, and oxidative stress. We further link post-translational regulation of K(+) channels with programmed cell death and show that K(+) plays a critical role in controlling the latter process. Thus, is appears that K(+) is not just the essential nutrient required to support optimal plant growth and yield but is also an important signaling agent mediating a wide range of plant adaptive responses to environment.
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Affiliation(s)
- Uta Anschütz
- University of Wuerzburg, Plant Molecular Biology & Biophysics, Wuerzburg, Germany
| | - Dirk Becker
- University of Wuerzburg, Plant Molecular Biology & Biophysics, Wuerzburg, Germany.
| | - Sergey Shabala
- School of Agricultural Science, University of Tasmania, Hobart, Australia
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4
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Jahn L, Mucha S, Bergmann S, Horn C, Staswick P, Steffens B, Siemens J, Ludwig-Müller J. The Clubroot Pathogen (Plasmodiophora brassicae) Influences Auxin Signaling to Regulate Auxin Homeostasis in Arabidopsis. PLANTS 2013; 2:726-49. [PMID: 27137401 PMCID: PMC4844388 DOI: 10.3390/plants2040726] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 10/17/2013] [Accepted: 11/18/2013] [Indexed: 11/16/2022]
Abstract
The clubroot disease, caused by the obligate biotrophic protist Plasmodiophora brassicae, affects cruciferous crops worldwide. It is characterized by root swellings as symptoms, which are dependent on the alteration of auxin and cytokinin metabolism. Here, we describe that two different classes of auxin receptors, the TIR family and the auxin binding protein 1 (ABP1) in Arabidopsis thaliana are transcriptionally upregulated upon gall formation. Mutations in the TIR family resulted in more susceptible reactions to the root pathogen. As target genes for the different pathways we have investigated the transcriptional regulation of selected transcriptional repressors (Aux/IAA) and transcription factors (ARF). As the TIR pathway controls auxin homeostasis via the upregulation of some auxin conjugate synthetases (GH3), the expression of selected GH3 genes was also investigated, showing in most cases upregulation. A double gh3 mutant showed also slightly higher susceptibility to P. brassicae infection, while all tested single mutants did not show any alteration in the clubroot phenotype. As targets for the ABP1-induced cell elongation the effect of potassium channel blockers on clubroot formation was investigated. Treatment with tetraethylammonium (TEA) resulted in less severe clubroot symptoms. This research provides evidence for the involvement of two auxin signaling pathways in Arabidopsis needed for the establishment of the root galls by P. brassicae.
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Affiliation(s)
- Linda Jahn
- Institut für Botanik, Technische Universität Dresden, 01062 Dresden, Germany.
| | - Stefanie Mucha
- Institut für Botanik, Technische Universität Dresden, 01062 Dresden, Germany.
| | - Sabine Bergmann
- Institut für Botanik, Technische Universität Dresden, 01062 Dresden, Germany.
| | - Cornelia Horn
- Institut für Botanik, Technische Universität Dresden, 01062 Dresden, Germany.
| | - Paul Staswick
- Department of Agronomy and Horticulture, University of Nebraska, 379 Keim, Lincoln, NE 68521 USA.
| | - Bianka Steffens
- Botanisches Institut, Universität Kiel, Am Botanischen Garten 5, 24118 Kiel, Germany.
| | - Johannes Siemens
- Institut für Botanik, Technische Universität Dresden, 01062 Dresden, Germany.
| | - Jutta Ludwig-Müller
- Institut für Botanik, Technische Universität Dresden, 01062 Dresden, Germany.
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Remy E, Cabrito TR, Baster P, Batista RA, Teixeira MC, Friml J, Sá-Correia I, Duque P. A major facilitator superfamily transporter plays a dual role in polar auxin transport and drought stress tolerance in Arabidopsis. THE PLANT CELL 2013; 25:901-26. [PMID: 23524662 PMCID: PMC3634696 DOI: 10.1105/tpc.113.110353] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 02/01/2013] [Accepted: 03/05/2013] [Indexed: 05/18/2023]
Abstract
Many key aspects of plant development are regulated by the polarized transport of the phytohormone auxin. Cellular auxin efflux, the rate-limiting step in this process, has been shown to rely on the coordinated action of PIN-formed (PIN) and B-type ATP binding cassette (ABCB) carriers. Here, we report that polar auxin transport in the Arabidopsis thaliana root also requires the action of a Major Facilitator Superfamily (MFS) transporter, Zinc-Induced Facilitator-Like 1 (ZIFL1). Sequencing, promoter-reporter, and fluorescent protein fusion experiments indicate that the full-length ZIFL1.1 protein and a truncated splice isoform, ZIFL1.3, localize to the tonoplast of root cells and the plasma membrane of leaf stomatal guard cells, respectively. Using reverse genetics, we show that the ZIFL1.1 transporter regulates various root auxin-related processes, while the ZIFL1.3 isoform mediates drought tolerance by regulating stomatal closure. Auxin transport and immunolocalization assays demonstrate that ZIFL1.1 indirectly modulates cellular auxin efflux during shootward auxin transport at the root tip, likely by regulating plasma membrane PIN2 abundance. Finally, heterologous expression in yeast revealed that ZIFL1.1 and ZIFL1.3 share H(+)-coupled K(+) transport activity. Thus, by determining the subcellular and tissue distribution of two isoforms, alternative splicing dictates a dual function for the ZIFL1 transporter. We propose that this MFS carrier regulates stomatal movements and polar auxin transport by modulating potassium and proton fluxes in Arabidopsis cells.
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Affiliation(s)
- Estelle Remy
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal
| | - Tânia R. Cabrito
- Institute for Biotechnology and BioEngineering, Center for Biological and Chemical Engineering, Department of Bioengineering, Instituto Superior Técnico, Technical University of Lisbon, 1049-001 Lisbon, Portugal
| | - Pawel Baster
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), and Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | | | - Miguel C. Teixeira
- Institute for Biotechnology and BioEngineering, Center for Biological and Chemical Engineering, Department of Bioengineering, Instituto Superior Técnico, Technical University of Lisbon, 1049-001 Lisbon, Portugal
| | - Jiri Friml
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), and Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Isabel Sá-Correia
- Institute for Biotechnology and BioEngineering, Center for Biological and Chemical Engineering, Department of Bioengineering, Instituto Superior Técnico, Technical University of Lisbon, 1049-001 Lisbon, Portugal
| | - Paula Duque
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal
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Hohm T, Preuten T, Fankhauser C. Phototropism: translating light into directional growth. AMERICAN JOURNAL OF BOTANY 2013; 100:47-59. [PMID: 23152332 DOI: 10.3732/ajb.1200299] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Phototropism allows plants to align their photosynthetic tissues with incoming light. The direction of incident light is sensed by the phototropin family of blue light photoreceptors (phot1 and phot2 in Arabidopsis), which are light-activated protein kinases. The kinase activity of phototropins and phosphorylation of residues in the activation loop of their kinase domains are essential for the phototropic response. These initial steps trigger the formation of the auxin gradient across the hypocotyl that leads to asymmetric growth. The molecular events between photoreceptor activation and the growth response are only starting to be elucidated. In this review, we discuss the major steps leading from light perception to directional growth concentrating on Arabidopsis. In addition, we highlight links that connect these different steps enabling the phototropic response.
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Affiliation(s)
- Tim Hohm
- Department of Medical Genetics, Faculty of Biology and Medicine, University of Lausanne, Rue du Bugnon 27, CH-1005 Lausanne, Switzerland
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7
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Nitsch L, Kohlen W, Oplaat C, Charnikhova T, Cristescu S, Michieli P, Wolters-Arts M, Bouwmeester H, Mariani C, Vriezen WH, Rieu I. ABA-deficiency results in reduced plant and fruit size in tomato. JOURNAL OF PLANT PHYSIOLOGY 2012; 169:878-83. [PMID: 22424572 DOI: 10.1016/j.jplph.2012.02.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/15/2012] [Accepted: 02/16/2012] [Indexed: 05/08/2023]
Abstract
Abscisic acid (ABA) deficient mutants, such as notabilis and flacca, have helped elucidating the role of ABA during plant development and stress responses in tomato (Solanum lycopersicum L.). However, these mutants have only moderately decreased ABA levels. Here we report on plant and fruit development in the more strongly ABA-deficient notabilis/flacca (not/flc) double mutant. We observed that plant growth, leaf-surface area, drought-induced wilting and ABA-related gene expression in the different genotypes were strongly correlated with the ABA levels and thus most strongly affected in the not/flc double mutants. These mutants also had reduced fruit size that was caused by an overall smaller cell size. Lower ABA levels in fruits did not correlate with changes in auxin levels, but were accompanied by higher ethylene evolution rates. This suggests that in a wild-type background ABA stimulates cell enlargement during tomato fruit growth via a negative effect on ethylene synthesis.
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Affiliation(s)
- L Nitsch
- Radboud University Nijmegen, IWWR, Department of Molecular Plant Physiology, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
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8
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Lee Y, Park CH, Ram Kim A, Chang SC, Kim SH, Lee WS, Kim SK. The effect of ascorbic acid and dehydroascorbic acid on the root gravitropic response in Arabidopsis thaliana. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2011; 49:909-16. [PMID: 21696975 DOI: 10.1016/j.plaphy.2011.05.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 05/31/2011] [Indexed: 05/09/2023]
Abstract
The effects of ascorbic acid (AA) and dehydroascorbic acid (DHA), one of products of the disproportionation of monodehydroascorbate (MDHA) by AA oxidase (AAO, EC 1.10.3.3), on the gravitropic curvature of Arabidopsis roots were characterized by biochemical and genetic approaches. Exogenously applied AA and DHA both stimulated root gravitropic responses in a concentration-dependent fashion. AA also changed the Indole-3-acetic acid (IAA) distribution in the roots after gravistimulation. In an effort to determine the relationship between AA and DHA in the gravitropic response, changes in the amount of reduced AA were evaluated in Arabidopsis under a variety of conditions. The expression level of an AAO gene (AAO1) was increased upon gravistimulation. Brassinolide (BL), indole-3-acetic acid (IAA), and AA also increased the transcript levels of this gene. Root elongation and the gravitropic response were both suppressed in the AA biosynthesis mutant, vtc1, which has a greatly reduced level of total AA. Furthermore, the line of AAO double mutants (aao1-1 X aao3-1, 41-21) showed a reduced gravitropic response and reduced root elongation. Taken together, the results of this study imply that both AA and DHA help to determine the redox environment for the root gravitropic response, but DHA, rather than AA, is a major player in the regulation of the gravitropic response mediated by AA in the roots of Arabidopsis thaliana.
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Affiliation(s)
- Yew Lee
- Department of Life Science, Chung-Ang University, Seoul 156-756, Republic of Korea
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10
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Galon Y, Aloni R, Nachmias D, Snir O, Feldmesser E, Scrase-Field S, Boyce JM, Bouché N, Knight MR, Fromm H. Calmodulin-binding transcription activator 1 mediates auxin signaling and responds to stresses in Arabidopsis. PLANTA 2010; 232:165-78. [PMID: 20383645 DOI: 10.1007/s00425-010-1153-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 03/15/2010] [Indexed: 05/08/2023]
Abstract
Auxin is a key plant hormone that regulates various aspects of plant development. However, the mechanisms integrating auxin growth effects with stress responses are not fully understood. In this study, we investigated the possible role of calmodulin-binding transcription activator 1 (CAMTA1), an Arabidopsis thaliana calcium/calmodulin-binding transcription activator, in auxin signaling and its responses to different stresses. Plants harboring the AtCAMTA1 promoter fused to the GUS reporter gene revealed cell-specific expression patterns reminiscent of auxin responses. The responsiveness of CAMTA1 to auxin was further assessed by chemical disturbances in polar auxin transport, and by RT-PCR analysis of gene expression of dissected leaf sections from plants exposed to the auxin transport inhibitor NPA. Furthermore, the intensity and cell-specific expression patterns of CAMTA1 changed significantly and differentially on exposure to increasing salt concentrations and heat. Transcriptome analysis of a camta1 T-DNA insertion mutant revealed 63 up-regulated genes, of which 17 are associated with auxin signaling. Finally, analysis of hypocotyl elongation in the presence and absence of auxin revealed that camta1 T-DNA insertion mutants and CAMTA1-repressor lines are hyper-responsive to auxin compared to wild-type seedlings. Thus, CAMTA1 participates in auxin signaling and responds to abiotic stresses.
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Affiliation(s)
- Yael Galon
- Department of Plant Sciences, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
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11
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Sano T, Kutsuna N, Becker D, Hedrich R, Hasezawa S. Outward-rectifying K+ channel activities regulate cell elongation and cell division of tobacco BY-2 cells. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 57:55-64. [PMID: 18778403 DOI: 10.1111/j.1365-313x.2008.03672.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Potassium ions (K+) are required for plant growth and development, including cell division and cell elongation/expansion, which are mediated by the K+ transport system. In this study, we investigated the role of K+ in cell division using tobacco BY-2 protoplast cultures. Gene expression analysis revealed induction of the Shaker-like outward K+ channel gene, NTORK1, under cell-division conditions, whereas the inward K+ channel genes NKT1 and NtKC1 were induced under both cell-elongation and cell-division conditions. Repression of NTORK1 gene expression by expression of its antisense construct repressed cell division but accelerated cell elongation even under conditions promoting cell division. A decrease in the K+ content of cells and cellular osmotic pressure in dividing cells suggested that an increase in cell osmotic pressure by K+ uptake is not required for cell division. In contrast, K+ depletion, which reduced cell-division activity, decreased cytoplasmic pH as monitored using a fluorescent pH indicator, SNARF-1. Application of K+ or the cytoplasmic alkalizing reagent (NH(4))(2)SO(4) increased cytoplasmic pH and suppressed the reduction in cell-division activity. These results suggest that the K+ taken up into cells is used to regulate cytoplasmic pH during cell division.
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Affiliation(s)
- Toshio Sano
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan
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Fuchs I, Philippar K, Hedrich R. Ion channels meet auxin action. PLANT BIOLOGY (STUTTGART, GERMANY) 2006; 8:353-9. [PMID: 16807828 DOI: 10.1055/s-2006-924121] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The regulation of cell division and elongation in plants is accomplished by the action of different phytohormones. Auxin as one of these growth regulators is known to stimulate cell elongation growth in the aerial parts of the plant. Here, auxin enhances cell enlargement by increasing the extensibility of the cell wall and by facilitating the uptake of osmolytes such as potassium ions into the cell. Starting in the late 1990s, the auxin regulation of ion channels mediating K+ import into the cell has been studied in great detail. In this article we will focus on the molecular mechanisms underlying the modulation of K+ transport by auxin and present a model to explain how the regulation of K+ channels is involved in auxin-induced cell elongation growth.
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Affiliation(s)
- I Fuchs
- Julius-von-Sachs-Institute, Molecular Plant Physiology and Biophysics, Biocenter Würzburg University, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany
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13
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Christian M, Steffens B, Schenck D, Burmester S, Böttger M, Lüthen H. How does auxin enhance cell elongation? Roles of auxin-binding proteins and potassium channels in growth control. PLANT BIOLOGY (STUTTGART, GERMANY) 2006; 8:346-52. [PMID: 16807827 DOI: 10.1055/s-2006-923965] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Elongation growth and a several other phenomena in plant development are controlled by the plant hormone auxin. A number of recent discoveries shed light on one of the classical problems of plant physiology: the perception of the auxin signal. Two types of auxin receptors are currently known: the AFB/TIR family of F box proteins and ABP1. ABP1 appears to control membrane transport processes (H+ secretion, osmotic adjustment) while the TIR/AFBs have a role in auxin-induced gene expression. Models are proposed to explain how membrane transport (e.g., K+ and H+ fluxes) can act as a cross-linker for the control of more complex auxin responses such as the classical stimulation of cell elongation.
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Affiliation(s)
- M Christian
- Biozentrum Klein Flottbek, Physiologie, Universität Hamburg, Ohnhorststrasse 18, 22609 Hamburg, Germany
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