1
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The SV, Santiago JP, Pappenberger C, Hammes UZ, Tegeder M. UMAMIT44 is a key player in glutamate export from Arabidopsis chloroplasts. Plant Cell 2024; 36:1119-1139. [PMID: 38092462 PMCID: PMC10980354 DOI: 10.1093/plcell/koad310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 11/15/2023] [Indexed: 04/01/2024]
Abstract
Selective partitioning of amino acids among organelles, cells, tissues, and organs is essential for cellular metabolism and plant growth. Nitrogen assimilation into glutamine and glutamate and de novo biosynthesis of most protein amino acids occur in chloroplasts; therefore, various transport mechanisms must exist to accommodate their directional efflux from the stroma to the cytosol and feed the amino acids into the extraplastidial metabolic and long-distance transport pathways. Yet, Arabidopsis (Arabidopsis thaliana) transporters functioning in plastidial export of amino acids remained undiscovered. Here, USUALLY MULTIPLE ACIDS MOVE IN AND OUT TRANSPORTER 44 (UMAMIT44) was identified and shown to function in glutamate export from Arabidopsis chloroplasts. UMAMIT44 controls glutamate homeostasis within and outside of chloroplasts and influences nitrogen partitioning from leaves to sinks. Glutamate imbalances in chloroplasts and leaves of umamit44 mutants impact cellular redox state, nitrogen and carbon metabolism, and amino acid (AA) and sucrose supply of growing sinks, leading to negative effects on plant growth. Nonetheless, the mutant lines adjust to some extent by upregulating alternative pathways for glutamate synthesis outside the plastids and by mitigating oxidative stress through the production of other amino acids and antioxidants. Overall, this study establishes that the role of UMAMIT44 in glutamate export from chloroplasts is vital for controlling nitrogen availability within source leaf cells and for sink nutrition, with an impact on growth and seed yield.
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Affiliation(s)
- Samantha Vivia The
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - James P Santiago
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Clara Pappenberger
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
| | - Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
| | - Mechthild Tegeder
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
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2
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Roth O, Yechezkel S, Serero O, Eliyahu A, Vints I, Tzeela P, Carignano A, Janacek DP, Peters V, Kessel A, Dwivedi V, Carmeli-Weissberg M, Shaya F, Faigenboim-Doron A, Ung KL, Pedersen BP, Riov J, Klavins E, Dawid C, Hammes UZ, Ben-Tal N, Napier R, Sadot E, Weinstain R. Slow release of a synthetic auxin induces formation of adventitious roots in recalcitrant woody plants. Nat Biotechnol 2024:10.1038/s41587-023-02065-3. [PMID: 38267759 DOI: 10.1038/s41587-023-02065-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 11/15/2023] [Indexed: 01/26/2024]
Abstract
Clonal propagation of plants by induction of adventitious roots (ARs) from stem cuttings is a requisite step in breeding programs. A major barrier exists for propagating valuable plants that naturally have low capacity to form ARs. Due to the central role of auxin in organogenesis, indole-3-butyric acid is often used as part of commercial rooting mixtures, yet many recalcitrant plants do not form ARs in response to this treatment. Here we describe the synthesis and screening of a focused library of synthetic auxin conjugates in Eucalyptus grandis cuttings and identify 4-chlorophenoxyacetic acid-L-tryptophan-OMe as a competent enhancer of adventitious rooting in a number of recalcitrant woody plants, including apple and argan. Comprehensive metabolic and functional analyses reveal that this activity is engendered by prolonged auxin signaling due to initial fast uptake and slow release and clearance of the free auxin 4-chlorophenoxyacetic acid. This work highlights the utility of a slow-release strategy for bioactive compounds for more effective plant growth regulation.
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Affiliation(s)
- Ohad Roth
- School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Sela Yechezkel
- The Institute of Plant Sciences, The Volcani Center, Ministry of Agriculture and Rural Development, Rishon LeZion, Israel
| | - Ori Serero
- The Institute of Plant Sciences, The Volcani Center, Ministry of Agriculture and Rural Development, Rishon LeZion, Israel
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Avi Eliyahu
- The Institute of Plant Sciences, The Volcani Center, Ministry of Agriculture and Rural Development, Rishon LeZion, Israel
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Inna Vints
- School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Pan Tzeela
- The Institute of Plant Sciences, The Volcani Center, Ministry of Agriculture and Rural Development, Rishon LeZion, Israel
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Alberto Carignano
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA
| | - Dorina P Janacek
- Chair of Plant Systems Biology, Technical University of Munich, Freising, Germany
| | - Verena Peters
- Chair of Food Chemistry and Molecular and Sensory Science, Technical University of Munich, Freising, Germany
| | - Amit Kessel
- Department of Biochemistry and Molecular BiologySchool of Neurobiology, Biochemistry & Biophysics, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Vikas Dwivedi
- The Institute of Plant Sciences, The Volcani Center, Ministry of Agriculture and Rural Development, Rishon LeZion, Israel
| | - Mira Carmeli-Weissberg
- The Institute of Plant Sciences, The Volcani Center, Ministry of Agriculture and Rural Development, Rishon LeZion, Israel
| | - Felix Shaya
- The Institute of Plant Sciences, The Volcani Center, Ministry of Agriculture and Rural Development, Rishon LeZion, Israel
| | - Adi Faigenboim-Doron
- The Institute of Plant Sciences, The Volcani Center, Ministry of Agriculture and Rural Development, Rishon LeZion, Israel
| | - Kien Lam Ung
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | | | - Joseph Riov
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Eric Klavins
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA
| | - Corinna Dawid
- Chair of Food Chemistry and Molecular and Sensory Science, Technical University of Munich, Freising, Germany
| | - Ulrich Z Hammes
- Chair of Plant Systems Biology, Technical University of Munich, Freising, Germany
| | - Nir Ben-Tal
- Department of Biochemistry and Molecular BiologySchool of Neurobiology, Biochemistry & Biophysics, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Richard Napier
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Einat Sadot
- The Institute of Plant Sciences, The Volcani Center, Ministry of Agriculture and Rural Development, Rishon LeZion, Israel.
| | - Roy Weinstain
- School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
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3
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Hammes UZ, Pedersen BP. Structure and Function of Auxin Transporters. Annu Rev Plant Biol 2024; 75. [PMID: 38211951 DOI: 10.1146/annurev-arplant-070523-034109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Auxins, a group of central hormones in plant growth and development, are transported by a diverse range of transporters with distinct biochemical and structural properties. This review summarizes the current knowledge on all known auxin transporters with respect to their biochemical and biophysical properties and the methods used to characterize them. In particular, we focus on the recent advances that were made concerning the PIN-FORMED family of auxin exporters. Insights derived from solving their structures have improved our understanding of the auxin export process, and we discuss the current state of the art on PIN-mediated auxin transport, including the use of biophysical methods to examine their properties. Understanding the mechanisms of auxin transport is crucial for understanding plant growth and development, as well as for the development of more effective strategies for crop production and plant biotechnology. Expected final online publication date for the Annual Review of Plant Biology, Volume 75 is May 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany;
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4
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Ung KL, Schulz L, Kleine-Vehn J, Pedersen BP, Hammes UZ. Auxin transport at the endoplasmic reticulum: roles and structural similarity of PIN-FORMED and PIN-LIKES. J Exp Bot 2023; 74:6893-6903. [PMID: 37279330 DOI: 10.1093/jxb/erad192] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 06/02/2023] [Indexed: 06/08/2023]
Abstract
Auxin is a crucial plant hormone that controls a multitude of developmental processes. The directional movement of auxin between cells is largely facilitated by canonical PIN-FORMED proteins in the plasma membrane. In contrast, non-canonical PIN-FORMED proteins and PIN-LIKES proteins appear to reside mainly in the endoplasmic reticulum. Despite recent progress in identifying the roles of the endoplasmic reticulum in cellular auxin responses, the transport dynamics of auxin at the endoplasmic reticulum are not well understood. PIN-LIKES are structurally related to PIN-FORMED proteins, and recently published structures of these transporters have provided new insights into PIN-FORMED proteins and PIN-LIKES function. In this review, we summarize current knowledge on PIN-FORMED proteins and PIN-LIKES in intracellular auxin transport. We discuss the physiological properties of the endoplasmic reticulum and the consequences for transport processes across the ER membrane. Finally, we highlight the emerging role of the endoplasmic reticulum in the dynamics of cellular auxin signalling and its impact on plant development.
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Affiliation(s)
- Kien Lam Ung
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Lukas Schulz
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
| | - Jürgen Kleine-Vehn
- Institute of Biology II, Department of Molecular Plant Physiology (MoPP), University of Freiburg, 79104 Freiburg, Germany
- Center for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, 79104 Freiburg, Germany
| | | | - Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
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5
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Ung KL, Schulz L, Stokes DL, Hammes UZ, Pedersen BP. Substrate recognition and transport mechanism of the PIN-FORMED auxin exporters. Trends Biochem Sci 2023; 48:937-948. [PMID: 37574372 PMCID: PMC10592131 DOI: 10.1016/j.tibs.2023.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/30/2023] [Accepted: 07/17/2023] [Indexed: 08/15/2023]
Abstract
Auxins are pivotal plant hormones that regulate plant growth and transmembrane polar auxin transport (PAT) direct patterns of development. The PIN-FORMED (PIN) family of membrane transporters mediate auxin export from the plant cell and play crucial roles in PAT. Here we describe the recently solved structures of PIN transporters, PIN1, PIN3, and PIN8, and also their mechanisms of substrate recognition and transport of auxin. We compare structures of PINs in both inward- and outward-facing conformations, as well as PINs with different binding configurations for auxin. By this comparative analysis, a model emerges for an elevator transport mechanism. Central structural elements necessary for function are identified, and we show that these are shared with other distantly related protein families.
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Affiliation(s)
- Kien Lam Ung
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Lukas Schulz
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
| | - David L Stokes
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, NY 10016, USA
| | - Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
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6
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Wuest SE, Schulz L, Rana S, Frommelt J, Ehmig M, Pires ND, Grossniklaus U, Hardtke CS, Hammes UZ, Schmid B, Niklaus PA. Single-gene resolution of diversity-driven overyielding in plant genotype mixtures. Nat Commun 2023; 14:3379. [PMID: 37291153 PMCID: PMC10250416 DOI: 10.1038/s41467-023-39130-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 05/30/2023] [Indexed: 06/10/2023] Open
Abstract
In plant communities, diversity often increases productivity and functioning, but the specific underlying drivers are difficult to identify. Most ecological theories attribute positive diversity effects to complementary niches occupied by different species or genotypes. However, the specific nature of niche complementarity often remains unclear, including how it is expressed in terms of trait differences between plants. Here, we use a gene-centred approach to study positive diversity effects in mixtures of natural Arabidopsis thaliana genotypes. Using two orthogonal genetic mapping approaches, we find that between-plant allelic differences at the AtSUC8 locus are strongly associated with mixture overyielding. AtSUC8 encodes a proton-sucrose symporter and is expressed in root tissues. Genetic variation in AtSUC8 affects the biochemical activities of protein variants and natural variation at this locus is associated with different sensitivities of root growth to changes in substrate pH. We thus speculate that - in the particular case studied here - evolutionary divergence along an edaphic gradient resulted in the niche complementarity between genotypes that now drives overyielding in mixtures. Identifying genes important for ecosystem functioning may ultimately allow linking ecological processes to evolutionary drivers, help identify traits underlying positive diversity effects, and facilitate the development of high-performance crop variety mixtures.
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Affiliation(s)
- Samuel E Wuest
- Department of Evolutionary Biology and Environmental Studies and Zurich-Basel Plant Science Center, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
- Department of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland.
- Department of Geography, Remote Sensing Laboratories, University of Zurich, 8057, Zurich, Switzerland.
- Agroscope, Group Breeding Research, Mueller-Thurgau-Strasse 29, 8820, Waedenswil, Switzerland.
| | - Lukas Schulz
- Plant Systems Biology, School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Surbhi Rana
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne, 1015, Switzerland
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Colney Ln, Norwich, NR4 7UH, United Kingdom
| | - Julia Frommelt
- Department of Evolutionary Biology and Environmental Studies and Zurich-Basel Plant Science Center, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Merten Ehmig
- Department of Systematic and Evolutionary Botany, University of Zurich, Zollikerstrasse 107, 8008, Zürich, Switzerland
| | - Nuno D Pires
- Department of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland
| | - Christian S Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne, 1015, Switzerland
| | - Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Bernhard Schmid
- Department of Evolutionary Biology and Environmental Studies and Zurich-Basel Plant Science Center, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
- Department of Geography, Remote Sensing Laboratories, University of Zurich, 8057, Zurich, Switzerland
| | - Pascal A Niklaus
- Department of Evolutionary Biology and Environmental Studies and Zurich-Basel Plant Science Center, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
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7
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Yang S, de Haan M, Mayer J, Janacek DP, Hammes UZ, Poppenberger B, Sieberer T. A novel chemical inhibitor of polar auxin transport promotes shoot regeneration by local enhancement of HD-ZIP III transcription. New Phytol 2022; 235:1111-1128. [PMID: 35491431 DOI: 10.1111/nph.18196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
De novo shoot organogenesis is a prerequisite for numerous applications in plant research and breeding but is often a limiting factor, for example, in genome editing approaches. Class III homeodomain-leucine zipper (HD-ZIP III) transcription factors have been characterized as crucial regulators of shoot specification, however up-stream components controlling their activity during shoot regeneration are only partially identified. In a chemical genetic screen, we isolated ZIC2, a novel activator of HD-ZIP III activity. Using molecular, physiological and hormone transport analyses in Arabidopsis and sunflower (Helianthus annuus), we examined the molecular mechanism by which the drug promotes HD-ZIP III expression. ZIC2-dependent upregulation of HD-ZIP III transcription promotes shoot regeneration in Arabidopsis and is accompanied by the induction of shoot specifying factors WUS and RAP2.6L and a subset of cytokinin biosynthesis enzymes. ZIC2's effect on HD-ZIP III expression and regeneration is based on its ability to limit polar auxin transport. We further provide evidence that chemical modulation of auxin efflux can enhance de novo shoot formation in the regeneration recalcitrant species sunflower. Activation of HD-ZIP III transcription during shoot regeneration depends on the local distribution of auxin and chemical modulation of auxin transport can be used to overcome poor shoot organogenesis in tissue culture.
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Affiliation(s)
- Saiqi Yang
- Research Unit Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Marjolein de Haan
- Research Unit Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Julius Mayer
- Research Unit Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Dorina P Janacek
- Plant Systems Biology, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Ulrich Z Hammes
- Plant Systems Biology, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Tobias Sieberer
- Research Unit Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
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8
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Ung KL, Winkler M, Schulz L, Kolb M, Janacek DP, Dedic E, Stokes DL, Hammes UZ, Pedersen BP. Structures and mechanism of the plant PIN-FORMED auxin transporter. Nature 2022; 609:605-610. [PMID: 35768502 PMCID: PMC9477730 DOI: 10.1038/s41586-022-04883-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 05/19/2022] [Indexed: 11/15/2022]
Abstract
Auxins are hormones that have central roles and control nearly all aspects of growth and development in plants1–3. The proteins in the PIN-FORMED (PIN) family (also known as the auxin efflux carrier family) are key participants in this process and control auxin export from the cytosol to the extracellular space4–9. Owing to a lack of structural and biochemical data, the molecular mechanism of PIN-mediated auxin transport is not understood. Here we present biophysical analysis together with three structures of Arabidopsis thaliana PIN8: two outward-facing conformations with and without auxin, and one inward-facing conformation bound to the herbicide naphthylphthalamic acid. The structure forms a homodimer, with each monomer divided into a transport and scaffold domain with a clearly defined auxin binding site. Next to the binding site, a proline–proline crossover is a pivot point for structural changes associated with transport, which we show to be independent of proton and ion gradients and probably driven by the negative charge of the auxin. The structures and biochemical data reveal an elevator-type transport mechanism reminiscent of bile acid/sodium symporters, bicarbonate/sodium symporters and sodium/proton antiporters. Our results provide a comprehensive molecular model for auxin recognition and transport by PINs, link and expand on a well-known conceptual framework for transport, and explain a central mechanism of polar auxin transport, a core feature of plant physiology, growth and development. Structural and biophysical analysis of the Arabidopsis thaliana auxin transporter PIN8 reveal that PIN transporters export auxin using an elevator mechanism.
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Affiliation(s)
- Kien Lam Ung
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Mikael Winkler
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Lukas Schulz
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Martina Kolb
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Dorina P Janacek
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Emil Dedic
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - David L Stokes
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York University School of Medicine, New York, NY, USA
| | - Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.
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9
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Abstract
From embryogenesis to fruit formation, almost every aspect of plant development and differentiation is controlled by the cellular accumulation or depletion of auxin from cells and tissues. The respective auxin maxima and minima are generated by cell-to-cell auxin transport via transporter proteins. Differential auxin accumulation as a result of such transport processes dynamically regulates auxin distribution during differentiation. In this review, we introduce all auxin transporter (families) identified to date and discuss the knowledge on prominent family members, namely, the PIN-FORMED exporters, ATP-binding cassette B (ABCB)-type transporters, and AUX1/LAX importers. We then concentrate on the biochemical features of these transporters and their regulation by posttranslational modifications and interactors.
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Affiliation(s)
- Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences, Technical University of Munich, 85354 Freising, Germany
| | - Angus S Murphy
- Department of Plant Science and Landscape Architecture
- Agriculture Biotechnology Center, University of Maryland, College Park, Maryland 20742, USA
| | - Claus Schwechheimer
- Plant Systems Biology, School of Life Sciences, Technical University of Munich, 85354 Freising, Germany
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10
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Koh SWH, Marhava P, Rana S, Graf A, Moret B, Bassukas AEL, Zourelidou M, Kolb M, Hammes UZ, Schwechheimer C, Hardtke CS. Mapping and engineering of auxin-induced plasma membrane dissociation in BRX family proteins. Plant Cell 2021; 33:1945-1960. [PMID: 33751121 PMCID: PMC8290284 DOI: 10.1093/plcell/koab076] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 03/03/2021] [Indexed: 05/04/2023]
Abstract
Angiosperms have evolved the phloem for the long-distance transport of metabolites. The complex process of phloem development involves genes that only occur in vascular plant lineages. For example, in Arabidopsis thaliana, the BREVIS RADIX (BRX) gene is required for continuous root protophloem differentiation, together with PROTEIN KINASE ASSOCIATED WITH BRX (PAX). BRX and its BRX-LIKE (BRXL) homologs are composed of four highly conserved domains including the signature tandem BRX domains that are separated by variable spacers. Nevertheless, BRX family proteins have functionally diverged. For instance, BRXL2 can only partially replace BRX in the root protophloem. This divergence is reflected in physiologically relevant differences in protein behavior, such as auxin-induced plasma membrane dissociation of BRX, which is not observed for BRXL2. Here we dissected the differential functions of BRX family proteins using a set of amino acid substitutions and domain swaps. Our data suggest that the plasma membrane-associated tandem BRX domains are both necessary and sufficient to convey the biological outputs of BRX function and therefore constitute an important regulatory entity. Moreover, PAX target phosphosites in the linker between the two BRX domains mediate the auxin-induced plasma membrane dissociation. Engineering these sites into BRXL2 renders this modified protein auxin-responsive and thereby increases its biological activity in the root protophloem context.
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Affiliation(s)
- Samuel W H Koh
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Petra Marhava
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Surbhi Rana
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Alina Graf
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Bernard Moret
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | | | - Melina Zourelidou
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Martina Kolb
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Ulrich Z Hammes
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Claus Schwechheimer
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Christian S Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
- Author for correspondence:
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11
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Abas L, Kolb M, Stadlmann J, Janacek DP, Lukic K, Schwechheimer C, Sazanov LA, Mach L, Friml J, Hammes UZ. Naphthylphthalamic acid associates with and inhibits PIN auxin transporters. Proc Natl Acad Sci U S A 2021; 118:e2020857118. [PMID: 33443187 PMCID: PMC7817115 DOI: 10.1073/pnas.2020857118] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 11/12/2020] [Indexed: 12/22/2022] Open
Abstract
N-1-naphthylphthalamic acid (NPA) is a key inhibitor of directional (polar) transport of the hormone auxin in plants. For decades, it has been a pivotal tool in elucidating the unique polar auxin transport-based processes underlying plant growth and development. Its exact mode of action has long been sought after and is still being debated, with prevailing mechanistic schemes describing only indirect connections between NPA and the main transporters responsible for directional transport, namely PIN auxin exporters. Here we present data supporting a model in which NPA associates with PINs in a more direct manner than hitherto postulated. We show that NPA inhibits PIN activity in a heterologous oocyte system and that expression of NPA-sensitive PINs in plant, yeast, and oocyte membranes leads to specific saturable NPA binding. We thus propose that PINs are a bona fide NPA target. This offers a straightforward molecular basis for NPA inhibition of PIN-dependent auxin transport and a logical parsimonious explanation for the known physiological effects of NPA on plant growth, as well as an alternative hypothesis to interpret past and future results. We also introduce PIN dimerization and describe an effect of NPA on this, suggesting that NPA binding could be exploited to gain insights into structural aspects of PINs related to their transport mechanism.
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Affiliation(s)
- Lindy Abas
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), 1190 Vienna, Austria;
| | - Martina Kolb
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
| | - Johannes Stadlmann
- Department of Chemistry, University of Natural Resources and Life Sciences (BOKU), 1190 Vienna, Austria
| | - Dorina P Janacek
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
| | - Kristina Lukic
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Claus Schwechheimer
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
| | - Leonid A Sazanov
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Lukas Mach
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), 1190 Vienna, Austria
| | - Jiří Friml
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany;
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12
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Marhava P, Aliaga Fandino AC, Koh SW, Jelínková A, Kolb M, Janacek DP, Breda AS, Cattaneo P, Hammes UZ, Petrášek J, Hardtke CS. Plasma Membrane Domain Patterning and Self-Reinforcing Polarity in Arabidopsis. Dev Cell 2020; 52:223-235.e5. [DOI: 10.1016/j.devcel.2019.11.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/08/2019] [Accepted: 11/21/2019] [Indexed: 10/25/2022]
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13
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Skokan R, Medvecká E, Viaene T, Vosolsobě S, Zwiewka M, Müller K, Skůpa P, Karady M, Zhang Y, Janacek DP, Hammes UZ, Ljung K, Nodzyński T, Petrášek J, Friml J. PIN-driven auxin transport emerged early in streptophyte evolution. Nat Plants 2019; 5:1114-1119. [PMID: 31712756 DOI: 10.1038/s41477-019-0542-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 10/07/2019] [Indexed: 05/27/2023]
Abstract
PIN-FORMED (PIN) transporters mediate directional, intercellular movement of the phytohormone auxin in land plants. To elucidate the evolutionary origins of this developmentally crucial mechanism, we analysed the single PIN homologue of a simple green alga Klebsormidium flaccidum. KfPIN functions as a plasma membrane-localized auxin exporter in land plants and heterologous models. While its role in algae remains unclear, PIN-driven auxin export is probably an ancient and conserved trait within streptophytes.
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Affiliation(s)
- Roman Skokan
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
- The Czech Academy of Sciences, Institute of Experimental Botany, Prague, Czech Republic
| | - Eva Medvecká
- CEITEC, Masaryk University, Mendel Centre for Genomics and Proteomics of Plants Systems, Brno, Czech Republic
| | - Tom Viaene
- Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Stanislav Vosolsobě
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Marta Zwiewka
- CEITEC, Masaryk University, Mendel Centre for Genomics and Proteomics of Plants Systems, Brno, Czech Republic
| | - Karel Müller
- The Czech Academy of Sciences, Institute of Experimental Botany, Prague, Czech Republic
| | - Petr Skůpa
- The Czech Academy of Sciences, Institute of Experimental Botany, Prague, Czech Republic
| | - Michal Karady
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, Sweden
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc, Czech Republic
| | | | - Dorina P Janacek
- School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Ulrich Z Hammes
- School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Karin Ljung
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Tomasz Nodzyński
- CEITEC, Masaryk University, Mendel Centre for Genomics and Proteomics of Plants Systems, Brno, Czech Republic
| | - Jan Petrášek
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
- The Czech Academy of Sciences, Institute of Experimental Botany, Prague, Czech Republic
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Höwing T, Dann M, Müller B, Helm M, Scholz S, Schneitz K, Hammes UZ, Gietl C. The role of KDEL-tailed cysteine endopeptidases of Arabidopsis (AtCEP2 and AtCEP1) in root development. PLoS One 2018; 13:e0209407. [PMID: 30576358 PMCID: PMC6303060 DOI: 10.1371/journal.pone.0209407] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 12/05/2018] [Indexed: 12/17/2022] Open
Abstract
Plants encode a unique group of papain-type cysteine endopeptidases (CysEP) characterized by a C-terminal KDEL endoplasmic reticulum retention signal (KDEL-CysEP) and an unusually broad substrate specificity. The three Arabidopsis KDEL-CysEPs (AtCEP1, AtCEP2, and AtCEP3) are differentially expressed in vegetative and generative tissues undergoing programmed cell death (PCD). While KDEL-CysEPs have been shown to be implicated in the collapse of tissues during PCD, roles of these peptidases in processes other than PCD are unknown. Using mCherry-AtCEP2 and EGFP-AtCEP1 reporter proteins in wild type versus atcep2 or atcep1 mutant plants, we explored the participation of AtCEP in young root development. Loss of AtCEP2, but not AtCEP1 resulted in shorter primary roots due to a decrease in cell length in the lateral root (LR) cap, and impairs extension of primary root epidermis cells such as trichoblasts in the elongation zone. AtCEP2 was localized to root cap corpses adherent to epidermal cells in the rapid elongation zone. AtCEP1 and AtCEP2 are expressed in root epidermis cells that are separated for LR emergence. Loss of AtCEP1 or AtCEP2 caused delayed emergence of LR primordia. KDEL-CysEPs might be involved in developmental tissue remodeling by supporting cell wall elongation and cell separation.
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Affiliation(s)
- Timo Höwing
- Lehrstuhl für Botanik, Center of Life and Food Sciences Weihenstephan, Technische Universitaet Muenchen, Freising, Germany
| | - Marcel Dann
- Lehrstuhl für Botanik, Center of Life and Food Sciences Weihenstephan, Technische Universitaet Muenchen, Freising, Germany
| | - Benedikt Müller
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Regensburg, Germany
| | - Michael Helm
- Lehrstuhl für Botanik, Center of Life and Food Sciences Weihenstephan, Technische Universitaet Muenchen, Freising, Germany
| | - Sebastian Scholz
- Plant Developmental Biology, Center of Life and Food Sciences Weihenstephan, Technische Universitaet Muenchen, Freising, Germany
| | - Kay Schneitz
- Plant Developmental Biology, Center of Life and Food Sciences Weihenstephan, Technische Universitaet Muenchen, Freising, Germany
| | - Ulrich Z. Hammes
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Regensburg, Germany
| | - Christine Gietl
- Lehrstuhl für Botanik, Center of Life and Food Sciences Weihenstephan, Technische Universitaet Muenchen, Freising, Germany
- * E-mail:
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15
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Karmann J, Müller B, Hammes UZ. The long and winding road: transport pathways for amino acids in Arabidopsis seeds. Plant Reprod 2018; 31:253-261. [PMID: 29549431 DOI: 10.1007/s00497-018-0334-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 03/07/2018] [Indexed: 05/02/2023]
Abstract
Pathways for assimilates. During their life cycle, plants alternate between a haploid stage, the gametophyte, and a diploid stage, the sporophyte. In higher plants, meiosis generates the gametophyte deeply embedded in the maternal tissue of the flower. The megaspore mother cell undergoes meiosis, and then, the surviving megaspore of the four megaspores produced undergoes mitotic divisions and finally gives rise to the female gametophyte, consisting of the egg cell, two synergids, the central cell, which due to the fusion of two nuclei is diploid (double haploid) in Arabidopsis and most angiosperms and the antipods, whose number is not fixed and varies significantly between species (Yadegari and Drews in Plant Cell 16(Suppl):S133-S141, 2004). The maternal tissues that harbor the female gametophyte and the female gametophyte are referred to as the ovule (Fig. 1). Double fertilization of the egg cell and the central cell by the two generative nuclei of the pollen leads to the diploid embryo and the endosperm, respectively (Hamamura et al. in Curr Opin Plant Biol 15:70-77, 2012). Upon fertilization, the ovule is referred to as the seed. Seeds combine two purposes: to harbor storage compounds for use by the embryo upon germination and to protect the embryo until the correct conditions for germination are encountered. As a consequence, seeds are the plant tissue that is of highest nutritional value and the human diet, by a considerable amount, consists of seeds or seed-derived products. Amino acids are of special interest, because plants serve as the main source for the so-called essential amino acids, that animals cannot synthesize de novo and are therefore often a limiting factor for human growth and development (WHO in Protein and amino acid requirements in human nutrition. WHO technical report series, WHO, Geneva, 2007). The plant embryo needs amino acids for general protein synthesis, and additionally they are used to synthesize storage proteins in the seeds of certain plants, e.g., legumes as a resource to support the growth of the seedling after germination. The support of the embryo depends on transport processes that occur between the mother plant and the seed tissues including the embryo. In this review, we will focus on the processes of unloading amino acids from the phloem and their post-phloem transport. We will further highlight similarities between amino acid transport and the transport of the main assimilate and osmolyte, sucrose. Finally, we will discuss similarities and differences between different plant species in terms of structural aspects but for the molecular aspects we are almost exclusively focusing on Arabidopsis. Fig. 1 Vascularization of the Arabidopsis ovule and seed. Plants expressing ER-localized mCherry under control of the companion cell-specific SUC2 promoter and ER-localized GFP under control of the sieve element marker PD1 as described (Müller et al. 2015) are shown to visualize the phloem in the funiculus and the chalazal regions. a Overview over an ovule. FG: female gametophyte. b A magnification of the region marked by a square in panel a. c Overview over a seed. ES: endosperm; E: embryo. d A magnification of the region marked by a square in panel c. The arrows in b and d point to the terminal companion cell and arrowheads to terminal sieve elements.
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Affiliation(s)
- Julia Karmann
- Chair of Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, Emil-Ramann-Strasse 8, 85354, Freising, Germany
| | - Benedikt Müller
- Chair of Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, Emil-Ramann-Strasse 8, 85354, Freising, Germany
| | - Ulrich Z Hammes
- Chair of Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, Emil-Ramann-Strasse 8, 85354, Freising, Germany.
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16
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Barbosa ICR, Hammes UZ, Schwechheimer C. Activation and Polarity Control of PIN-FORMED Auxin Transporters by Phosphorylation. Trends Plant Sci 2018; 23:523-538. [PMID: 29678589 DOI: 10.1016/j.tplants.2018.03.009] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 03/11/2018] [Accepted: 03/14/2018] [Indexed: 05/09/2023]
Abstract
Auxin controls almost every aspect of plant development. Auxin is distributed within the plant by passive diffusion and active cell-to-cell transport. PIN-FORMED (PIN) auxin efflux transporters are polarly distributed in the plasma membranes of many cells, and knowledge about their distribution can predict auxin transport and explain auxin distribution patterns, even in complex tissues. Recent studies have revealed that phosphorylation is essential for PIN activation, suggesting that PIN phosphorylation needs to be taken into account in understanding auxin transport. These findings also ask for a re-examination of previously proposed mechanisms for phosphorylation-dependent PIN polarity control. We provide a comprehensive summary of the current knowledge on PIN regulation by phosphorylation, and discuss possible mechanisms of PIN polarity control in the context of recent findings.
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Affiliation(s)
- Inês C R Barbosa
- Department of Plant Molecular Biology, Biophore Building, Unil-Sorge, Université de Lausanne, 1015 Lausanne, Switzerland; These authors contributed equally to this review article and are listed in alphabetical order
| | - Ulrich Z Hammes
- Plant Systems Biology, Technical University Munich, Emil-Ramann-Strasse 8, 85354 Freising, Germany; These authors contributed equally to this review article and are listed in alphabetical order
| | - Claus Schwechheimer
- Plant Systems Biology, Technical University Munich, Emil-Ramann-Strasse 8, 85354 Freising, Germany; These authors contributed equally to this review article and are listed in alphabetical order.
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17
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Tegeder M, Hammes UZ. The way out and in: phloem loading and unloading of amino acids. Curr Opin Plant Biol 2018; 43:16-21. [PMID: 29278790 DOI: 10.1016/j.pbi.2017.12.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/06/2017] [Accepted: 12/11/2017] [Indexed: 05/03/2023]
Abstract
Amino acids represent the major transport form of reduced nitrogen in plants. Long-distance transport of amino acids occurs in the xylem and the phloem. However, the phloem is the main transport route for bulk flow of the organic nitrogen from source leaves to sink tissues. Phloem loading in leaves of most annual plant species follows an apoplasmic transport path and requires the coordinated activity of transport protein mediating cellular export or import of amino acids. Phloem unloading of amino acids is generally a symplasmic process but apoplasmic transport is additionally required for efficient post-phloem nitrogen transport. In this review we summarize the current data on the physiology of amino acid phloem loading and unloading, and the molecular players involved. We discuss the implications of amino acid transporters in nitrogen signaling and highlight the necessity to investigate the coordination of symplasmic and apoplasmic transport processes.
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Affiliation(s)
- Mechthild Tegeder
- School of Biological Sciences, Washington State University, Pullman, WA, USA.
| | - Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, Germany
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18
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Abstract
Xenopus laevis oocytes are an expression system that is particularly well suited for the characterization of membrane transporters. Oocytes possess only very little endogenous transport systems and therefore transporters can be studied with a high signal-to-noise ratio. This book chapter provides the basic methods to use Xenopus oocytes for the characterization of transporters by radiotracer experiments. While the methods described here were established to study auxin transport they can easily be adapted to study other hormone transporters and their substrates.
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Affiliation(s)
- Astrid Fastner
- Cell Biology and Plant Biochemistry, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Birgit Absmanner
- Cell Biology and Plant Biochemistry, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Ulrich Z Hammes
- Cell Biology and Plant Biochemistry, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
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19
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Ge Y, Yan F, Zourelidou M, Wang M, Ljung K, Fastner A, Hammes UZ, Di Donato M, Geisler M, Schwechheimer C, Tao Y. SHADE AVOIDANCE 4 Is Required for Proper Auxin Distribution in the Hypocotyl. Plant Physiol 2017; 173:788-800. [PMID: 27872246 PMCID: PMC5210748 DOI: 10.1104/pp.16.01491] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 11/17/2016] [Indexed: 05/25/2023]
Abstract
The phytohormone auxin is involved in virtually every aspect of plant growth and development. Through polar auxin transport, auxin gradients can be established, which then direct plant differentiation and growth. Shade avoidance responses are well-known processes that require polar auxin transport. In this study, we have identified a mutant, shade avoidance 4 (sav4), defective in shade-induced hypocotyl elongation and basipetal auxin transport. SAV4 encodes an unknown protein with armadillo repeat- and tetratricopeptide repeat-like domains known to provide protein-protein interaction surfaces. C terminally yellow fluorescent protein-tagged SAV4 localizes to both the plasma membrane and the nucleus. Membrane-localized SAV4 displays a polar association with the shootward plasma membrane domain in hypocotyl and root cells, which appears to be necessary for its function in hypocotyl elongation. Cotransfection of SAV4 and ATP-binding cassette B1 (ABCB1) auxin transporter in tobacco (Nicotiana benthamiana) revealed that SAV4 blocks ABCB1-mediated auxin efflux. We thus propose that polarly localized SAV4 acts to inhibit ABCB-mediated auxin efflux toward shoots and facilitates the establishment of proper auxin gradients.
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Affiliation(s)
- Yanhua Ge
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory (Y.G., F.Y., M.W., Y.T.), and State Key Laboratory of Cellular Stress Biology (Y.G., Y.T.), Xiamen University, Xiamen 361102, China
- Department of Plant Systems Biology, Technische Universität München, Freising 85354, Germany (M.Z., C.S.)
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden (K.L.)
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg 93047, Germany (A.F., U.Z.H.); and
- Department of Biology-Plant Biology, University of Fribourg, CH-1700 Fribourg, Switzerland (M.D.D., M.G.)
| | - Fenglian Yan
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory (Y.G., F.Y., M.W., Y.T.), and State Key Laboratory of Cellular Stress Biology (Y.G., Y.T.), Xiamen University, Xiamen 361102, China
- Department of Plant Systems Biology, Technische Universität München, Freising 85354, Germany (M.Z., C.S.)
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden (K.L.)
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg 93047, Germany (A.F., U.Z.H.); and
- Department of Biology-Plant Biology, University of Fribourg, CH-1700 Fribourg, Switzerland (M.D.D., M.G.)
| | - Melina Zourelidou
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory (Y.G., F.Y., M.W., Y.T.), and State Key Laboratory of Cellular Stress Biology (Y.G., Y.T.), Xiamen University, Xiamen 361102, China
- Department of Plant Systems Biology, Technische Universität München, Freising 85354, Germany (M.Z., C.S.)
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden (K.L.)
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg 93047, Germany (A.F., U.Z.H.); and
- Department of Biology-Plant Biology, University of Fribourg, CH-1700 Fribourg, Switzerland (M.D.D., M.G.)
| | - Meiling Wang
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory (Y.G., F.Y., M.W., Y.T.), and State Key Laboratory of Cellular Stress Biology (Y.G., Y.T.), Xiamen University, Xiamen 361102, China
- Department of Plant Systems Biology, Technische Universität München, Freising 85354, Germany (M.Z., C.S.)
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden (K.L.)
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg 93047, Germany (A.F., U.Z.H.); and
- Department of Biology-Plant Biology, University of Fribourg, CH-1700 Fribourg, Switzerland (M.D.D., M.G.)
| | - Karin Ljung
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory (Y.G., F.Y., M.W., Y.T.), and State Key Laboratory of Cellular Stress Biology (Y.G., Y.T.), Xiamen University, Xiamen 361102, China
- Department of Plant Systems Biology, Technische Universität München, Freising 85354, Germany (M.Z., C.S.)
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden (K.L.)
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg 93047, Germany (A.F., U.Z.H.); and
- Department of Biology-Plant Biology, University of Fribourg, CH-1700 Fribourg, Switzerland (M.D.D., M.G.)
| | - Astrid Fastner
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory (Y.G., F.Y., M.W., Y.T.), and State Key Laboratory of Cellular Stress Biology (Y.G., Y.T.), Xiamen University, Xiamen 361102, China
- Department of Plant Systems Biology, Technische Universität München, Freising 85354, Germany (M.Z., C.S.)
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden (K.L.)
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg 93047, Germany (A.F., U.Z.H.); and
- Department of Biology-Plant Biology, University of Fribourg, CH-1700 Fribourg, Switzerland (M.D.D., M.G.)
| | - Ulrich Z Hammes
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory (Y.G., F.Y., M.W., Y.T.), and State Key Laboratory of Cellular Stress Biology (Y.G., Y.T.), Xiamen University, Xiamen 361102, China
- Department of Plant Systems Biology, Technische Universität München, Freising 85354, Germany (M.Z., C.S.)
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden (K.L.)
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg 93047, Germany (A.F., U.Z.H.); and
- Department of Biology-Plant Biology, University of Fribourg, CH-1700 Fribourg, Switzerland (M.D.D., M.G.)
| | - Martin Di Donato
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory (Y.G., F.Y., M.W., Y.T.), and State Key Laboratory of Cellular Stress Biology (Y.G., Y.T.), Xiamen University, Xiamen 361102, China
- Department of Plant Systems Biology, Technische Universität München, Freising 85354, Germany (M.Z., C.S.)
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden (K.L.)
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg 93047, Germany (A.F., U.Z.H.); and
- Department of Biology-Plant Biology, University of Fribourg, CH-1700 Fribourg, Switzerland (M.D.D., M.G.)
| | - Markus Geisler
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory (Y.G., F.Y., M.W., Y.T.), and State Key Laboratory of Cellular Stress Biology (Y.G., Y.T.), Xiamen University, Xiamen 361102, China
- Department of Plant Systems Biology, Technische Universität München, Freising 85354, Germany (M.Z., C.S.)
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden (K.L.)
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg 93047, Germany (A.F., U.Z.H.); and
- Department of Biology-Plant Biology, University of Fribourg, CH-1700 Fribourg, Switzerland (M.D.D., M.G.)
| | - Claus Schwechheimer
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory (Y.G., F.Y., M.W., Y.T.), and State Key Laboratory of Cellular Stress Biology (Y.G., Y.T.), Xiamen University, Xiamen 361102, China
- Department of Plant Systems Biology, Technische Universität München, Freising 85354, Germany (M.Z., C.S.)
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden (K.L.)
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg 93047, Germany (A.F., U.Z.H.); and
- Department of Biology-Plant Biology, University of Fribourg, CH-1700 Fribourg, Switzerland (M.D.D., M.G.)
| | - Yi Tao
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory (Y.G., F.Y., M.W., Y.T.), and State Key Laboratory of Cellular Stress Biology (Y.G., Y.T.), Xiamen University, Xiamen 361102, China;
- Department of Plant Systems Biology, Technische Universität München, Freising 85354, Germany (M.Z., C.S.);
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden (K.L.);
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg 93047, Germany (A.F., U.Z.H.); and
- Department of Biology-Plant Biology, University of Fribourg, CH-1700 Fribourg, Switzerland (M.D.D., M.G.)
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Zhou LZ, Höwing T, Müller B, Hammes UZ, Gietl C, Dresselhaus T. Expression analysis of KDEL-CysEPs programmed cell death markers during reproduction in Arabidopsis. Plant Reprod 2016; 29:265-72. [PMID: 27349421 DOI: 10.1007/s00497-016-0288-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 06/14/2016] [Indexed: 05/23/2023]
Abstract
CEP cell death markers. Programmed cell death (PCD) is essential for proper plant growth and development. Plant-specific papain-type KDEL-tailed cysteine endopeptidases (KDEL-CysEPs or CEPs) have been shown to be involved in PCD during vegetative development as executors for the last step in the process. The Arabidopsis genome encodes three KDEL-CysEPs: AtCEP1, AtCEP2 and AtCEP3. With the help of fluorescent fusion reporter lines, we report here a detailed expression analysis of KDEL-CysEP (pro)proteins during reproductive processes, including flower organ and germline development, fertilization and seed development. AtCEP1 is highly expressed in different reproductive tissues including nucellus cells of mature ovule and the connecting edge of anther and filament. After fertilization, AtCEP1 marks integument cell layers of the seeds coat as well as suspensor and columella cells of the developing embryo. Promoter activity of AtCEP2 is detected in the style of immature and mature pistils, in other floral organs including anther, sepal and petal. AtCEP2 mainly localizes to parenchyma cells next to xylem vessels. Although there is no experimental evidence to demonstrate that KDEL-CysEPs are involved in PCD during fertilization, the expression pattern of AtCEPs, which were previously shown to represent cell death markers during vegetative development, opens up new avenues to investigate PCD in plant reproduction.
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Affiliation(s)
- Liang-Zi Zhou
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93040, Regensburg, Germany
| | - Timo Höwing
- Center of Life and Food Sciences Weihenstephan, Lehrstuhl für Botanik, Technische Universität München, Emil-Ramann-Str. 4, 85350, Freising, Germany
| | - Benedikt Müller
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93040, Regensburg, Germany
| | - Ulrich Z Hammes
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93040, Regensburg, Germany
| | - Christine Gietl
- Center of Life and Food Sciences Weihenstephan, Lehrstuhl für Botanik, Technische Universität München, Emil-Ramann-Str. 4, 85350, Freising, Germany
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93040, Regensburg, Germany.
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21
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Hammes UZ. Under pressure. eLife 2016; 5. [PMID: 27417294 PMCID: PMC4946877 DOI: 10.7554/elife.18435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 07/08/2016] [Indexed: 12/02/2022] Open
Abstract
The movement of water by osmosis causes pressure differences that drive the transport of sugars over long distances in plants.
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Affiliation(s)
- Ulrich Z Hammes
- Department of Cell Biology and Plant Biochemistry, Regensburg University, Regensburg, Germany
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22
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Hammes UZ. Novel roles for phytosulfokine signalling in plant-pathogen interactions. Plant Cell Environ 2016; 39:1393-1395. [PMID: 26574181 DOI: 10.1111/pce.12679] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 11/10/2015] [Indexed: 06/05/2023]
Abstract
This article comments on: Evolutionarily distant pathogens require the Arabidopsis phytosulfokine signalling pathway to establish disease.
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Affiliation(s)
- Ulrich Z Hammes
- Cell Biology and Plant Biochemistry, University of Regensburg, 93053, Regensburg, Germany.
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23
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Vaddepalli P, Herrmann A, Fulton L, Oelschner M, Hillmer S, Stratil TF, Fastner A, Hammes UZ, Ott T, Robinson DG, Schneitz K. The C2-domain protein QUIRKY and the receptor-like kinase STRUBBELIG localize to plasmodesmata and mediate tissue morphogenesis in Arabidopsis thaliana. Development 2014; 141:4139-48. [DOI: 10.1242/dev.113878] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Tissue morphogenesis in plants requires communication between cells, a process involving the trafficking of molecules through plasmodesmata (PD). PD conductivity is regulated by endogenous and exogenous signals. However, the underlying signaling mechanisms remain enigmatic. In Arabidopsis, signal transduction mediated by the receptor-like kinase STRUBBELIG (SUB) contributes to inter-cell layer signaling during tissue morphogenesis. Previous analysis has revealed that SUB acts non-cell-autonomously suggesting that SUB controls tissue morphogenesis by participating in the formation or propagation of a downstream mobile signal. A genetic screen identified QUIRKY (QKY), encoding a predicted membrane-anchored C2-domain protein, as a component of SUB signaling. Here, we provide further insight into the role of QKY in this process. We show that like SUB, QKY exhibits non-cell-autonomy when expressed in a tissue-specific manner and that non-autonomy of QKY extends across several cells. In addition, we report on localization studies indicating that QKY and SUB localize to PD but independently of each other. FRET-FLIM analysis suggests that SUB and QKY are in close contact at PD in vivo. We propose a model where SUB and QKY interact at PD to promote tissue morphogenesis, thereby linking RLK-dependent signal transduction and intercellular communication mediated by PD.
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Affiliation(s)
- Prasad Vaddepalli
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Emil-Ramann-Strasse 4, Freising 85354, Germany
| | - Anja Herrmann
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Emil-Ramann-Strasse 4, Freising 85354, Germany
| | - Lynette Fulton
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Emil-Ramann-Strasse 4, Freising 85354, Germany
| | - Maxi Oelschner
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Emil-Ramann-Strasse 4, Freising 85354, Germany
| | - Stefan Hillmer
- Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, Heidelberg 69120, Germany
| | - Thomas F. Stratil
- Institute of Genetics, Faculty of Biology, Ludwig-Maximilians-University of Munich, Grosshaderner Strasse 2-4, Martinsried 82152, Germany
| | - Astrid Fastner
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstrasse 31, Regensburg 93053, Germany
| | - Ulrich Z. Hammes
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstrasse 31, Regensburg 93053, Germany
| | - Thomas Ott
- Institute of Genetics, Faculty of Biology, Ludwig-Maximilians-University of Munich, Grosshaderner Strasse 2-4, Martinsried 82152, Germany
| | - David G. Robinson
- Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, Heidelberg 69120, Germany
| | - Kay Schneitz
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Emil-Ramann-Strasse 4, Freising 85354, Germany
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24
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Zourelidou M, Absmanner B, Weller B, Barbosa ICR, Willige BC, Fastner A, Streit V, Port SA, Colcombet J, de la Fuente van Bentem S, Hirt H, Kuster B, Schulze WX, Hammes UZ, Schwechheimer C. Auxin efflux by PIN-FORMED proteins is activated by two different protein kinases, D6 PROTEIN KINASE and PINOID. eLife 2014; 3. [PMID: 24948515 DOI: 10.7554/elife.02860.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 06/17/2014] [Indexed: 05/27/2023] Open
Abstract
The development and morphology of vascular plants is critically determined by synthesis and proper distribution of the phytohormone auxin. The directed cell-to-cell distribution of auxin is achieved through a system of auxin influx and efflux transporters. PIN-FORMED (PIN) proteins are proposed auxin efflux transporters, and auxin fluxes can seemingly be predicted based on the--in many cells--asymmetric plasma membrane distribution of PINs. Here, we show in a heterologous Xenopus oocyte system as well as in Arabidopsis thaliana inflorescence stems that PIN-mediated auxin transport is directly activated by D6 PROTEIN KINASE (D6PK) and PINOID (PID)/WAG kinases of the Arabidopsis AGCVIII kinase family. At the same time, we reveal that D6PKs and PID have differential phosphosite preferences. Our study suggests that PIN activation by protein kinases is a crucial component of auxin transport control that must be taken into account to understand auxin distribution within the plant.
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Affiliation(s)
- Melina Zourelidou
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
| | - Birgit Absmanner
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg, Germany
| | - Benjamin Weller
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
| | - Inês C R Barbosa
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
| | - Björn C Willige
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
| | - Astrid Fastner
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg, Germany
| | - Verena Streit
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
| | - Sarah A Port
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
| | - Jean Colcombet
- Unité de Recherche en Génomique Végétale, Université Evry, Evry, France
| | | | - Heribert Hirt
- Unité de Recherche en Génomique Végétale, Université Evry, Evry, France
| | - Bernhard Kuster
- Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
| | | | - Ulrich Z Hammes
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg, Germany
| | - Claus Schwechheimer
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
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25
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Zourelidou M, Absmanner B, Weller B, Barbosa ICR, Willige BC, Fastner A, Streit V, Port SA, Colcombet J, de la Fuente van Bentem S, Hirt H, Kuster B, Schulze WX, Hammes UZ, Schwechheimer C. Auxin efflux by PIN-FORMED proteins is activated by two different protein kinases, D6 PROTEIN KINASE and PINOID. eLife 2014; 3. [PMID: 24948515 PMCID: PMC4091124 DOI: 10.7554/elife.02860] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 06/17/2014] [Indexed: 12/20/2022] Open
Abstract
The development and morphology of vascular plants is critically determined by synthesis and proper distribution of the phytohormone auxin. The directed cell-to-cell distribution of auxin is achieved through a system of auxin influx and efflux transporters. PIN-FORMED (PIN) proteins are proposed auxin efflux transporters, and auxin fluxes can seemingly be predicted based on the—in many cells—asymmetric plasma membrane distribution of PINs. Here, we show in a heterologous Xenopus oocyte system as well as in Arabidopsis thaliana inflorescence stems that PIN-mediated auxin transport is directly activated by D6 PROTEIN KINASE (D6PK) and PINOID (PID)/WAG kinases of the Arabidopsis AGCVIII kinase family. At the same time, we reveal that D6PKs and PID have differential phosphosite preferences. Our study suggests that PIN activation by protein kinases is a crucial component of auxin transport control that must be taken into account to understand auxin distribution within the plant. DOI:http://dx.doi.org/10.7554/eLife.02860.001 In plants, a hormone called auxin controls the growth of the stems and roots. This chemical is transported from cell to cell, and its flow though the plant is redirected continuously as the plant is developing. Auxin is pumped out of cells by proteins in the cell membrane called ‘auxin efflux carriers’. These proteins are usually found on one side of each cell and this is what gives the direction to auxin transport. Zourelidou, Absmanner et al. now report that being positioned on the correct side of a plant cell is not enough to enable an efflux carrier to do its job—it must also be turned on by kinases before it can pump auxin out of cells. Kinases are enzymes that add phosphate groups to specific sites on other proteins, and plants without certain kinases are unable to transport auxin. When Zourelidou, Absmanner et al. produced the efflux carrier and a plant kinase—which turns the efflux carrier on—in immature egg cells from frogs, auxin was rapidly pumped out of the cells. However, cells that contained the efflux carrier but not the kinase could not transport the hormone. Importantly egg cells from frogs do not normally transport auxin, but these cells are commonly used in experiments because they are large, which makes them easier to work with in the lab. One of at least two kinases must tag a number of sites on the efflux carrier to ensure that it is switched on. It was already known that some of these sites are involved in making sure that the efflux carrier is located on the correct side of the cell. Zourelidou, Absmanner et al. also found that auxin itself encourages the addition of phosphate groups onto the efflux carrier. Though it was thought that knowing where the auxin transporters are was enough to explain the direction of auxin transport in plants, it is now clear that activation by the kinases needs to be taken into account too. And since these kinases may activate the transporters to different extents, identifying how these proteins are controlled, for example by auxin itself, will be the next challenge in the field. DOI:http://dx.doi.org/10.7554/eLife.02860.002
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Affiliation(s)
- Melina Zourelidou
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
| | - Birgit Absmanner
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg, Germany
| | - Benjamin Weller
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
| | - Inês C R Barbosa
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
| | - Björn C Willige
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
| | - Astrid Fastner
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg, Germany
| | - Verena Streit
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
| | - Sarah A Port
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
| | - Jean Colcombet
- Unité de Recherche en Génomique Végétale, Université Evry, Evry, France
| | | | - Heribert Hirt
- Unité de Recherche en Génomique Végétale, Université Evry, Evry, France
| | - Bernhard Kuster
- Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
| | | | - Ulrich Z Hammes
- Department of Cell Biology and Plant Biochemistry, Universität Regensburg, Regensburg, Germany
| | - Claus Schwechheimer
- Department of Plant Systems Biology, Technische Universität München, Freising, Germany
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26
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Abstract
Plants are constantly challenged by pathogens and pests, which can have a profound impact on the yield and quality of produce in agricultural systems. The vascular system of higher plants is critical for growth and for their ability to counteract changing external conditions, serving as a distribution network for water, nutrients, and photosynthates from the source organs to regions where they are in demand. Unfortunately, these features also make it an attractive target for pathogens and pests that demand access to a reliable supply of host resources. The vascular tissue of plants therefore often plays a central role in pathogen and parasite interactions. One of the more striking rearrangements of the host vascular system occurs during root-knot nematode infestation of plant roots. These sedentary endoparasites induce permanent feeding sites that are comprised of 'giant cells' and are subject to extensive changes in vascularization, resulting in the giant cells being encaged within a network of de novo formed xylem and phloem cells. Despite being considered critical to the function of the feeding site, the mechanisms underlying this vascularization have received surprisingly little attention when compared with the amount of research on giant cell development and function. An overview of the current knowledge on vascularization of root-knot nematode feeding sites is provided here and recent advances in our understanding of the transport mechanisms involved in nutrient delivery to these parasite-induced sinks are described.
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Affiliation(s)
- Derek G Bartlem
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
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27
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Absmanner B, Stadler R, Hammes UZ. Phloem development in nematode-induced feeding sites: the implications of auxin and cytokinin. Front Plant Sci 2013; 4:241. [PMID: 23847644 PMCID: PMC3703529 DOI: 10.3389/fpls.2013.00241] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 06/17/2013] [Indexed: 05/18/2023]
Abstract
Sedentary plant parasitic nematodes such as root-knot nematodes and cyst nematodes induce giant cells or syncytia, respectively, in their host plant's roots. These highly specialized structures serve as feeding sites from which exclusively the nematodes withdraw nutrients. While giant cells are symplastically isolated and obtain assimilates by transporter-mediated processes syncytia are massively connected to the phloem by plasmodesmata. To support the feeding sites and the nematode during their development, phloem is induced around syncytia and giant cells. In the case of syncytia the unloading phloem consists of sieve elements and companion cells and in the case of root knots it consists exclusively of sieve elements. We applied immunohistochemistry to identify the cells within the developing phloem that responded to auxin and cytokinin. Both feeding sites themselves did not respond to either hormone. We were able to show that in root knots an auxin response precedes the differentiation of these auxin responsive cells into phloem elements. This process appears to be independent of B-type Arabidopsis response regulators. Using additional markers for tissue identity we provide evidence that around giant cells protophloem is formed and proliferates dramatically. In contrast, the phloem around syncytia responded to both hormones. The presence of companion cells as well as hormone-responsive sieve elements suggests that metaphloem development occurs. The implication of auxin and cytokinin in the further development of the metaphloem is discussed.
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Affiliation(s)
- Birgit Absmanner
- Cell biology and plant biochemistry, University RegensburgRegensburg, Germany
| | - Ruth Stadler
- Molecular Plant Physiology, Friedrich Alexander University Erlangen NürnbergErlangen, Germany
| | - Ulrich Z. Hammes
- Cell biology and plant biochemistry, University RegensburgRegensburg, Germany
- *Correspondence: Ulrich Z. Hammes, Cell biology and plant biochemistry, University Regensburg, Universitaetsstrasse 31, 93053 Regensburg, Germany e-mail:
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Schönberger J, Hammes UZ, Dresselhaus T. In vivo visualization of RNA in plants cells using the λN₂₂ system and a GATEWAY-compatible vector series for candidate RNAs. Plant J 2012; 71:173-81. [PMID: 22268772 DOI: 10.1111/j.1365-313x.2012.04923.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The past decade has seen a tremendous increase in RNA research, which has demonstrated that RNAs are involved in many more processes than were previously thought. The dynamics of RNA synthesis towards their regulated activity requires the interplay of RNAs with numerous RNA binding proteins (RBPs). The localization of RNA, a mechanism for controlling translation in a spatial and temporal fashion, requires processing and assembly of RNA into transport granules in the nucleus, transport towards cytoplasmic destinations and regulation of its activity. Compared with animal model systems little is known about RNA dynamics and motility in plants. Commonly used methods to study RNA transport and localization are time-consuming, and require expensive equipment and a high level of experimental skill. Here, we introduce the λN₂₂ RNA stem-loop binding system for the in vivo visualization of RNA in plant cells. The λN₂₂ system consists of two components: the λN₂₂ RNA binding peptide and the corresponding box-B stem loops. We generated fusions of λN₂₂ to different fluorophores and a GATEWAY vector series for the simple fusion of any target RNA 5' or 3' to box-B stem loops. We show that the λN₂₂ system can be used to detect RNAs in transient expression assays, and that it offers advantages compared with the previously described MS2 system. Furthermore, the λN₂₂ system can be used in combination with the MS2 system to visualize different RNAs simultaneously in the same cell. The toolbox of vectors generated for both systems is easy to use and promises significant progress in our understanding of RNA transport and localization in plant cells.
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Affiliation(s)
- Johannes Schönberger
- Cell Biology and Plant Biochemistry, University of Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
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29
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Ladwig F, Stahl M, Ludewig U, Hirner AA, Hammes UZ, Stadler R, Harter K, Koch W. Siliques are Red1 from Arabidopsis acts as a bidirectional amino acid transporter that is crucial for the amino acid homeostasis of siliques. Plant Physiol 2012; 158:1643-55. [PMID: 22312005 PMCID: PMC3320175 DOI: 10.1104/pp.111.192583] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Many membrane proteins are involved in the transport of nutrients in plants. While the import of amino acids into plant cells is, in principle, well understood, their export has been insufficiently described. Here, we present the identification and characterization of the membrane protein Siliques Are Red1 (SIAR1) from Arabidopsis (Arabidopsis thaliana) that is able to translocate amino acids bidirectionally into as well as out of the cell. Analyses in yeast and oocytes suggest a SIAR1-mediated export of amino acids. In Arabidopsis, SIAR1 localizes to the plasma membrane and is expressed in the vascular tissue, in the pericycle, in stamen, and in the chalazal seed coat of ovules and developing seeds. Mutant alleles of SIAR1 accumulate anthocyanins as a symptom of reduced amino acid content in the early stages of silique development. Our data demonstrate that the SIAR1-mediated export of amino acids plays an important role in organic nitrogen allocation and particularly in amino acid homeostasis in developing siliques.
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Affiliation(s)
- Friederike Ladwig
- Zentrum für Molekularbiologie der Pflanzen, Plant Physiology, D-72076 Tuebingen, Germany.
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Hammes UZ, Meier S, Dietrich D, Ward JM, Rentsch D. Functional properties of the Arabidopsis peptide transporters AtPTR1 and AtPTR5. J Biol Chem 2010; 285:39710-7. [PMID: 20937801 DOI: 10.1074/jbc.m110.141457] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Arabidopsis di- and tripeptide transporters AtPTR1 and AtPTR5 were expressed in Xenopus laevis oocytes, and their selectivity and kinetic properties were determined by voltage clamping and by radioactive uptake. Dipeptide transport by AtPTR1 and AtPTR5 was found to be electrogenic and dependent on protons but not sodium. In the absence of dipeptides, both transporters showed proton-dependent leak currents that were inhibited by Phe-Ala (AtPTR5) and Phe-Ala, Trp-Ala, and Phe-Phe (AtPTR1). Phe-Ala was shown to reduce leak currents by binding to the substrate-binding site with a high apparent affinity. Inhibition of leak currents was only observed when the aromatic amino acids were present at the N-terminal position. AtPTR1 and AtPTR5 transport activity was voltage-dependent, and currents increased supralinearly with more negative membrane potentials and did not saturate. The voltage dependence of the apparent affinities differed between Ala-Ala, Ala-Lys, and Ala-Asp and was not conserved between the two transporters. The apparent affinity of AtPTR1 for these dipeptides was pH-dependent and decreased with decreasing proton concentration. In contrast to most proton-coupled transporters characterized so far, -I(max) increased at high pH, indicating that regulation of the transporter by pH overrides the importance of protons as co-substrate.
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Affiliation(s)
- Ulrich Z Hammes
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013 Bern, Switzerland
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31
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Bartetzko V, Sonnewald S, Vogel F, Hartner K, Stadler R, Hammes UZ, Börnke F. The Xanthomonas campestris pv. vesicatoria type III effector protein XopJ inhibits protein secretion: evidence for interference with cell wall-associated defense responses. Mol Plant Microbe Interact 2009; 22:655-64. [PMID: 19445590 DOI: 10.1094/mpmi-22-6-0655] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria uses the type III secretion system (T3SS) to inject effector proteins into cells of its Solanaceous host plants. It is generally assumed that these effectors manipulate host pathways to favor bacterial replication and survival. However, the molecular mechanisms by which type III effectors suppress host defense responses are far from being understood. Based on sequence similarity, Xanthomonas outer protein J (XopJ) is a member of the YopJ/AvrRxv family of SUMO peptidases and acetyltranferases, although its biochemical activity has not yet been demonstrated. Confocal laser scanning microscopy revealed that green fluorescent protein (GFP) fusions of XopJ are targeted to the plasma membrane when expressed in plant cells, which most likely involves N-myristoylation. In contrast to a XopJ(C235A) mutant disrupted in the catalytic triad sequence, the wild-type effector GFP fusion protein was also localized in vesicle-like structures colocalizing together with a Golgi marker protein, suggesting an effect of XopJ on vesicle trafficking. To explore an effect of XopJ on protein secretion, we used a GFP-based secretion assay. When a secreted (sec)GFP marker was coexpressed with XopJ in leaves of Nicotiana benthamiana, GFP fluorescence was retained in reticulate structures. In contrast, in plant cells expressing secGFP alone or along with the XopJ(C235A) mutant, no GFP fluorescence accumulated within the cells. Moreover, coexpressing secGFP together with XopJ led to a reduced accumulation of secGFP within the apoplastic fluid of N. benthamiana leaves, further showing that XopJ affects protein secretion. Transgenic expression of XopJ in Arabidopsis suppressed callose deposition elicited by a T3SS-negative mutant of Pseudomonas syringae pv. tomato DC3000. A role of XopJ in the inhibition of cell wall-based defense responses is discussed.
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Affiliation(s)
- Verena Bartetzko
- Institut für Biologie, Lehrstuhl für Biochemie, Friedrich Alexander Universität Erlangen-Nürnberg, Staudtstr. 5, 91058 Erlangen, Germany
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32
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Abstract
Amino acids represent the major form of reduced nitrogen that is transported in plants. Amino acid transporters in plants often show tissue-specific expression patterns and are used by plants to transport these metabolites from source to sink during development and under changing environmental conditions. We identified one amino acid transporter, AtCAT6, which is expressed in sink tissues such as lateral root primordia, flowers and seeds. Additionally AtCAT6 was induced during infestation of roots by the plant-parasitic root-knot nematode, Meloidogyne incognita. Quantitative reverse-transcriptase PCR revealed nematode inducibility throughout the duration of nematode infestation and in nematode-induced feeding sites. Promoter analyses confirmed expression in endogenous sink tissues and nematode-induced feeding sites. In Xenopus oocytes, AtCAT6 mediated electrogenic transport of proteinogenic as well as non-proteinogenic amino acids with moderate affinity. AtCAT6 transported large, neutral and cationic amino acids in preference to other amino acids. Knockout mutants of this transporter failed to grow on medium containing l-glutamine as the sole nitrogen source. Our data suggest that AtCAT6 plays a role in supplying amino acids to sink tissues of plants and nematode-induced feeding structures.
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Affiliation(s)
- Ulrich Z Hammes
- Donald Danforth Plant Science Center, 975 North Warson Road, St Louis, MO 63122, USA.
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Yang Y, Hammes UZ, Taylor CG, Schachtman DP, Nielsen E. High-affinity auxin transport by the AUX1 influx carrier protein. Curr Biol 2006; 16:1123-7. [PMID: 16677815 DOI: 10.1016/j.cub.2006.04.029] [Citation(s) in RCA: 261] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 04/11/2006] [Accepted: 04/12/2006] [Indexed: 12/27/2022]
Abstract
In plants, auxin is a key regulator of development and is unique among plant hormones in that its function requires polarized transport between neighboring cells to form concentration gradients across various plant tissues. Although putative auxin-influx and -efflux transporters have been identified by using molecular genetic approaches, a detailed functional understanding for many of these transporters remains undetermined. Here we present the functional characterization of the auxin-influx carrier AUX1. Upon expression of AUX1 in Xenopus oocytes, saturable, pH-dependent uptake of 3H-IAA was measured. Mutations in AUX1 that abrogate physiological responses to IAA in planta resulted in loss or reduction of 3H-IAA uptake in AUX1-expressing oocytes. AUX1-mediated uptake of 3H-IAA was reduced by the IAA analogs 2,4-D and 1-NOA, but not by other auxin analogs. The measured Km for AUX1-mediated uptake of 3H-IAA was at concentrations at which physiological responses are observed for exogenously added IAA and 2,4-D. This is the first report demonstrating detailed functional characteristics of a plant auxin-influx transporter. This biochemical characterization provides new insights and a novel tool for studying auxin entry into cells and its pivotal roles in plant growth and development.
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Affiliation(s)
- Yaodong Yang
- Donald Danforth Plant Science Center, 975 North Warson Road, Saint Louis, Missouri 63132, USA
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Hammes UZ, Schachtman DP, Berg RH, Nielsen E, Koch W, McIntyre LM, Taylor CG. Nematode-induced changes of transporter gene expression in Arabidopsis roots. Mol Plant Microbe Interact 2005; 18:1247-57. [PMID: 16478044 DOI: 10.1094/mpmi-18-1247] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Root-knot plant-parasitic nematodes (Meloidogyne spp.) account for much of the damage inflicted to plants by nematodes. The feeding sites of these nematodes consist of "giant" cells, which have characteristics of transfer cells found in other parts of plants. Increased transport activity across the plasma membrane is a hallmark of transfer cells, and giant cells provide nutrition for nematodes; therefore, we initiated a study to identify the transport processes that contribute to the development and function of nematode-induced feeding sites. The study was conducted over a 4-week period, during which time the large changes in the development of giant cells were documented. The Arabidopsis ATH1 GeneChip was used to identify the many transporter genes that were regulated by nematode infestation. Expression of 50 transporter genes from 18 different gene families was significantly changed upon nematode infestation. Sixteen transporter genes were studied in more detail using real-time reverse-transcriptase polymerase chain reaction to determine transcript abundance in nematode-induced galls that contain giant cells and uninfested regions of the root. Certain genes were expressed primarily in galls whereas others were expressed primarily in the uninfested regions of the root, and a third group was expressed evenly throughout the root. Multiple transport processes are regulated and these may play important roles in nematode feeding-site establishment and maintenance.
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Affiliation(s)
- Ulrich Z Hammes
- Donald Danforth Plant Science Center, 975 N. Warson Rd., St. Louis, MO 63132, USA
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