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Ma X, Zhao X, Zhang H, Zhang Y, Sun S, Li Y, Long Z, Liu Y, Zhang X, Li R, Tan L, Jiang L, Zhu JK, Li L. MAG2 and MAL Regulate Vesicle Trafficking and Auxin Homeostasis With Functional Redundancy. FRONTIERS IN PLANT SCIENCE 2022; 13:849532. [PMID: 35371137 PMCID: PMC8966843 DOI: 10.3389/fpls.2022.849532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
Auxin is a central phytohormone and controls almost all aspects of plant development and stress response. Auxin homeostasis is coordinately regulated by biosynthesis, catabolism, transport, conjugation, and deposition. Endoplasmic reticulum (ER)-localized MAIGO2 (MAG2) complex mediates tethering of arriving vesicles to the ER membrane, and it is crucial for ER export trafficking. Despite important regulatory roles of MAG2 in vesicle trafficking, the mag2 mutant had mild developmental abnormalities. MAG2 has one homolog protein, MAG2-Like (MAL), and the mal-1 mutant also had slight developmental phenotypes. In order to investigate MAG2 and MAL regulatory function in plant development, we generated the mag2-1 mal-1 double mutant. As expected, the double mutant exhibited serious developmental defects and more alteration in stress response compared with single mutants and wild type. Proteomic analysis revealed that signaling, metabolism, and stress response in mag2-1 mal-1 were affected, especially membrane trafficking and auxin biosynthesis, signaling, and transport. Biochemical and cell biological analysis indicated that the mag2-1 mal-1 double mutant had more serious defects in vesicle transport than the mag2-1 and mal-1 single mutants. The auxin distribution and abundance of auxin transporters were altered significantly in the mag2-1 and mal-1 single mutants and mag2-1 mal-1 double mutant. Our findings suggest that MAG2 and MAL regulate plant development and auxin homeostasis by controlling membrane trafficking, with functional redundancy.
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Affiliation(s)
- Xiaohui Ma
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Xiaonan Zhao
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Hailong Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Yiming Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Shanwen Sun
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Ying Li
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Zhengbiao Long
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Yuqi Liu
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Xiaomeng Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Rongxia Li
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Li Tan
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lixi Jiang
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lixin Li
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
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Abstract
Auxin biology as a field has been at the forefront of advances in delineating the structures, dynamics, and control of plant growth networks. Advances have been enabled by combining the complementary fields of top-down, holistic systems biology and bottom-up, build-to-understand synthetic biology. Continued collaboration between these approaches will facilitate our understanding of and ability to engineer auxin's control of plant growth, development, and physiology. There is a need for the application of similar complementary approaches to improving equity and justice through analysis and redesign of the human systems in which this research is undertaken.
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Affiliation(s)
- R Clay Wright
- Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia 24061, USA
| | - Britney L Moss
- Department of Biology, Whitman College, Walla Walla, Washington 99362, USA
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3
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Auxin Metabolome Profiling in the Arabidopsis Endoplasmic Reticulum Using an Optimised Organelle Isolation Protocol. Int J Mol Sci 2021; 22:ijms22179370. [PMID: 34502279 PMCID: PMC8431077 DOI: 10.3390/ijms22179370] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 08/20/2021] [Accepted: 08/25/2021] [Indexed: 11/17/2022] Open
Abstract
The endoplasmic reticulum (ER) is an extensive network of intracellular membranes. Its major functions include proteosynthesis, protein folding, post-transcriptional modification and sorting of proteins within the cell, and lipid anabolism. Moreover, several studies have suggested that it may be involved in regulating intracellular auxin homeostasis in plants by modulating its metabolism. Therefore, to study auxin metabolome in the ER, it is necessary to obtain a highly enriched (ideally, pure) ER fraction. Isolation of the ER is challenging because its biochemical properties are very similar to those of other cellular endomembranes. Most published protocols for ER isolation use density gradient ultracentrifugation, despite its suboptimal resolving power. Here we present an optimised protocol for ER isolation from Arabidopsis thaliana seedlings for the subsequent mass spectrometric determination of ER-specific auxin metabolite profiles. Auxin metabolite analysis revealed highly elevated levels of active auxin form (IAA) within the ER compared to whole plants. Moreover, samples prepared using our optimised isolation ER protocol are amenable to analysis using various “omics” technologies including analyses of both macromolecular and low molecular weight compounds from the same sample.
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Gómez-Soto D, Ramos-Sánchez JM, Alique D, Conde D, Triozzi PM, Perales M, Allona I. Overexpression of a SOC1-Related Gene Promotes Bud Break in Ecodormant Poplars. FRONTIERS IN PLANT SCIENCE 2021; 12:670497. [PMID: 34113369 PMCID: PMC8185274 DOI: 10.3389/fpls.2021.670497] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 04/06/2021] [Indexed: 05/04/2023]
Abstract
Perennial species in the boreal and temperate regions are subject to extreme annual variations in light and temperature. They precisely adapt to seasonal changes by synchronizing cycles of growth and dormancy with external cues. Annual dormancy-growth transitions and flowering involve factors that integrate environmental and endogenous signals. MADS-box transcription factors have been extensively described in the regulation of Arabidopsis flowering. However, their participation in annual dormancy-growth transitions in trees is minimal. In this study, we investigate the function of MADS12, a Populus tremula × alba SUPPRESSOR OF CONSTANS OVEREXPRESSION 1 (SOC1)-related gene. Our gene expression analysis reveals that MADS12 displays lower mRNA levels during the winter than during early spring and mid-spring. Moreover, MADS12 activation depends on the fulfillment of the chilling requirement. Hybrid poplars overexpressing MADS12 show no differences in growth cessation and bud set, while ecodormant plants display an early bud break, indicating that MADS12 overexpression promotes bud growth reactivation. Comparative expression analysis of available bud break-promoting genes reveals that MADS12 overexpression downregulates the GIBBERELLINS 2 OXIDASE 4 (GA2ox4), a gene involved in gibberellin catabolism. Moreover, the mid-winter to mid-spring RNAseq profiling indicates that MADS12 and GA2ox4 show antagonistic expression during bud dormancy release. Our results support MADS12 participation in the reactivation of shoot meristem growth during ecodormancy and link MADS12 activation and GA2ox4 downregulation within the temporal events that lead to poplar bud break.
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Affiliation(s)
- Daniela Gómez-Soto
- Centro de Biotecnología y Genómica de Plantas, Instituto de Investigación y Tecnología Agraria y Alimentaria, Universidad Politécnica de Madrid, Madrid, Spain
| | - José M. Ramos-Sánchez
- Centro de Biotecnología y Genómica de Plantas, Instituto de Investigación y Tecnología Agraria y Alimentaria, Universidad Politécnica de Madrid, Madrid, Spain
| | - Daniel Alique
- Centro de Biotecnología y Genómica de Plantas, Instituto de Investigación y Tecnología Agraria y Alimentaria, Universidad Politécnica de Madrid, Madrid, Spain
| | - Daniel Conde
- Centro de Biotecnología y Genómica de Plantas, Instituto de Investigación y Tecnología Agraria y Alimentaria, Universidad Politécnica de Madrid, Madrid, Spain
| | - Paolo M. Triozzi
- Centro de Biotecnología y Genómica de Plantas, Instituto de Investigación y Tecnología Agraria y Alimentaria, Universidad Politécnica de Madrid, Madrid, Spain
| | - Mariano Perales
- Centro de Biotecnología y Genómica de Plantas, Instituto de Investigación y Tecnología Agraria y Alimentaria, Universidad Politécnica de Madrid, Madrid, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, Spain
| | - Isabel Allona
- Centro de Biotecnología y Genómica de Plantas, Instituto de Investigación y Tecnología Agraria y Alimentaria, Universidad Politécnica de Madrid, Madrid, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, Spain
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D E Lima CFF, Kleine-Vehn J, De Smet I, Feraru E. Getting to the Root of Belowground High Temperature Responses in Plants. JOURNAL OF EXPERIMENTAL BOTANY 2021:erab202. [PMID: 33970267 DOI: 10.1093/jxb/erab202] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Indexed: 06/12/2023]
Abstract
The environment is continuously challenging plants. As a response, plants use various coping strategies, such as adaptation of their growth. Thermomorphogenesis is a specific growth adaptation that promotes organ growth in response to moderately high temperature. This would eventually enable plants to cool down by dissipating the heat. Although well understood for shoot organs, the thermomorphogenesis response in roots only recently obtained increasing research attention. Accordingly, in the last few years, the hormonal responses and underlying molecular players important for root thermomorphogenesis were revealed. Other responses triggered by high temperature in the root encompass modifications of overall root architecture and interactions with the soil environment, with consequences on the whole plant. Here, we review the scientific knowledge and highlight the current understanding on roots responding to moderately high and extreme temperature.
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Affiliation(s)
- Cassio Flavio Fonseca D E Lima
- Ghent University, Department of Plant Biotechnology and Bioinformatics, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
| | - Jürgen Kleine-Vehn
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), Muthgasse 18, 1190 Vienna, Austria
- Faculty of Biology, 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
| | - Ive De Smet
- Ghent University, Department of Plant Biotechnology and Bioinformatics, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
| | - Elena Feraru
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), Muthgasse 18, 1190 Vienna, Austria
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6
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Root System Architecture Plasticity of Bread Wheat in Response to Oxidative Burst under Extended Osmotic Stress. PLANTS 2021; 10:plants10050939. [PMID: 34066687 PMCID: PMC8151492 DOI: 10.3390/plants10050939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/01/2021] [Accepted: 05/03/2021] [Indexed: 11/29/2022]
Abstract
There is a demand for an increase in crop production because of the growing population, but water shortage hinders the expansion of wheat cultivation, one of the most important crops worldwide. Polyethylene glycol (PEG) was used to mimic drought stress due to its high osmotic potentials generated in plants subjected to it. This study aimed to determine the root system architecture (RSA) plasticity of eight bread wheat genotypes under osmotic stress in relation to the oxidative status and mitochondrial membrane potential of their root tips. Osmotic stress application resulted in differences in the RSA between the eight genotypes, where genotypes were divided into adapted genotypes that have non-significant decreased values in lateral roots number (LRN) and total root length (TRL), while non-adapted genotypes have a significant decrease in LRN, TRL, root volume (RV), and root surface area (SA). Accumulation of intracellular ROS formation in root tips and elongation zone was observed in the non-adapted genotypes due to PEG-induced oxidative stress. Mitochondrial membrane potential (∆Ψm) was measured for both stress and non-stress treatments in the eight genotypes as a biomarker for programmed cell death as a result of induced osmotic stress, in correlation with RSA traits. PEG treatment increased scavenging capacity of the genotypes from 1.4-fold in the sensitive genotype Gemmiza 7 to 14.3-fold in the adapted genotype Sakha 94. The adapted genotypes showed greater root trait values, ∆Ψm plasticity correlated with high scavenging capacity, and less ROS accumulation in the root tissue, while the non-adapted genotypes showed little scavenging capacity in both treatments, accompanied by mitochondrial membrane permeability, suggesting mitochondrial dysfunction as a result of oxidative stress.
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Herud-Sikimić O, Stiel AC, Kolb M, Shanmugaratnam S, Berendzen KW, Feldhaus C, Höcker B, Jürgens G. A biosensor for the direct visualization of auxin. Nature 2021; 592:768-772. [PMID: 33828298 PMCID: PMC8081663 DOI: 10.1038/s41586-021-03425-2] [Citation(s) in RCA: 82] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 03/05/2021] [Indexed: 01/03/2023]
Abstract
One of the most important regulatory small molecules in plants is indole-3-acetic acid, also known as auxin. Its dynamic redistribution has an essential role in almost every aspect of plant life, ranging from cell shape and division to organogenesis and responses to light and gravity1,2. So far, it has not been possible to directly determine the spatial and temporal distribution of auxin at a cellular resolution. Instead it is inferred from the visualization of irreversible processes that involve the endogenous auxin-response machinery3-7; however, such a system cannot detect transient changes. Here we report a genetically encoded biosensor for the quantitative in vivo visualization of auxin distribution. The sensor is based on the Escherichia coli tryptophan repressor8, the binding pocket of which is engineered to be specific to auxin. Coupling of the auxin-binding moiety with selected fluorescent proteins enables the use of a fluorescence resonance energy transfer signal as a readout. Unlike previous systems, this sensor enables direct monitoring of the rapid uptake and clearance of auxin by individual cells and within cell compartments in planta. By responding to the graded spatial distribution along the root axis and its perturbation by transport inhibitors-as well as the rapid and reversible redistribution of endogenous auxin in response to changes in gravity vectors-our sensor enables real-time monitoring of auxin concentrations at a (sub)cellular resolution and their spatial and temporal changes during the lifespan of a plant.
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Affiliation(s)
| | - Andre C Stiel
- Max Planck Institute for Developmental Biology, Tübingen, Germany
- Institute for Biological and Medical Imaging, Helmholtz Zentrum Munich, German Research Center for Environmental Health, Munich, Germany
| | - Martina Kolb
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Sooruban Shanmugaratnam
- Max Planck Institute for Developmental Biology, Tübingen, Germany
- Department of Biochemistry, University of Bayreuth, Bayreuth, Germany
| | - Kenneth W Berendzen
- Centre for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
| | | | - Birte Höcker
- Max Planck Institute for Developmental Biology, Tübingen, Germany.
- Department of Biochemistry, University of Bayreuth, Bayreuth, Germany.
| | - Gerd Jürgens
- Max Planck Institute for Developmental Biology, Tübingen, Germany.
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8
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Geisler MM. A Retro-Perspective on Auxin Transport. FRONTIERS IN PLANT SCIENCE 2021; 12:756968. [PMID: 34675956 PMCID: PMC8524130 DOI: 10.3389/fpls.2021.756968] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 09/08/2021] [Indexed: 05/13/2023]
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9
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Abstract
Auxin is an endogenous small molecule with an incredibly large impact on growth and development in plants. Movement of auxin between cells, due to its negative charge at most physiological pHs, strongly relies on families of active transporters. These proteins import auxin from the extracellular space or export it into the same. Mutations in these components have profound impacts on biological processes. Another transport route available to auxin, once the substance is inside the cell, are plasmodesmata connections. These small channels connect the cytoplasms of neighbouring plant cells and enable flow between them. Interestingly, the biological significance of this latter mode of transport is only recently starting to emerge with examples from roots, hypocotyls and leaves. The existence of two transport systems provides opportunities for reciprocal cross-regulation. Indeed, auxin levels influence proteins controlling plasmodesmata permeability, while cell-cell communication affects auxin biosynthesis and transport. In an evolutionary context, transporter driven cell-cell auxin movement and plasmodesmata seem to have evolved around the same time in the green lineage. This highlights a co-existence from early on and a likely functional specificity of the systems. Exploring more situations where auxin movement via plasmodesmata has relevance for plant growth and development, and clarifying the regulation of such transport, will be key aspects in coming years.This article has an associated Future Leader to Watch interview with the author of the paper.
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Affiliation(s)
- Andrea Paterlini
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1 LR, UK
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Abdollahi Sisi N, Růžička K. ER-Localized PIN Carriers: Regulators of Intracellular Auxin Homeostasis. PLANTS 2020; 9:plants9111527. [PMID: 33182545 PMCID: PMC7697564 DOI: 10.3390/plants9111527] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 10/31/2020] [Accepted: 11/04/2020] [Indexed: 12/30/2022]
Abstract
The proper distribution of the hormone auxin is essential for plant development. It is channeled by auxin efflux carriers of the PIN family, typically asymmetrically located on the plasma membrane (PM). Several studies demonstrated that some PIN transporters are also located at the endoplasmic reticulum (ER). From the PM-PINs, they differ in a shorter internal hydrophilic loop, which carries the most important structural features required for their subcellular localization, but their biological role is otherwise relatively poorly known. We discuss how ER-PINs take part in maintaining intracellular auxin homeostasis, possibly by modulating the internal levels of IAA; it seems that the exact identity of the metabolites downstream of ER-PINs is not entirely clear as well. We further review the current knowledge about their predicted structure, evolution and localization. Finally, we also summarize their role in plant development.
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Affiliation(s)
- Nayyer Abdollahi Sisi
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, 16502 Prague, Czech Republic;
- Department of Experimental Plant Biology, Faculty of Science, Charles University, 12844 Prague, Czech Republic
| | - Kamil Růžička
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, 16502 Prague, Czech Republic;
- Correspondence: ; Tel.: +420-225-106-429
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11
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Kroll CK, Brenner WG. Cytokinin Signaling Downstream of the His-Asp Phosphorelay Network: Cytokinin-Regulated Genes and Their Functions. FRONTIERS IN PLANT SCIENCE 2020; 11:604489. [PMID: 33329676 PMCID: PMC7718014 DOI: 10.3389/fpls.2020.604489] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 10/26/2020] [Indexed: 05/17/2023]
Abstract
The plant hormone cytokinin, existing in several molecular forms, is perceived by membrane-localized histidine kinases. The signal is transduced to transcription factors of the type-B response regulator family localized in the nucleus by a multi-step histidine-aspartate phosphorelay network employing histidine phosphotransmitters as shuttle proteins across the nuclear envelope. The type-B response regulators activate a number of primary response genes, some of which trigger in turn further signaling events and the expression of secondary response genes. Most genes activated in both rounds of transcription were identified with high confidence using different transcriptomic toolkits and meta analyses of multiple individual published datasets. In this review, we attempt to summarize the existing knowledge about the primary and secondary cytokinin response genes in order to try connecting gene expression with the multitude of effects that cytokinin exerts within the plant body and throughout the lifespan of a plant.
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12
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Sauer M, Kleine-Vehn J. PIN-FORMED and PIN-LIKES auxin transport facilitators. Development 2019; 146:146/15/dev168088. [PMID: 31371525 DOI: 10.1242/dev.168088] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The phytohormone auxin influences virtually all aspects of plant growth and development. Auxin transport across membranes is facilitated by, among other proteins, members of the PIN-FORMED (PIN) and the structurally similar PIN-LIKES (PILS) families, which together govern directional cell-to-cell transport and intracellular accumulation of auxin. Canonical PIN proteins, which exhibit a polar localization in the plasma membrane, determine many patterning and directional growth responses. Conversely, the less-studied non-canonical PINs and PILS proteins, which mostly localize to the endoplasmic reticulum, attenuate cellular auxin responses. Here, and in the accompanying poster, we provide a brief summary of current knowledge of the structure, evolution, function and regulation of these auxin transport facilitators.
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Affiliation(s)
- Michael Sauer
- Institute for Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany
| | - Jürgen Kleine-Vehn
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences Vienna (BOKU), Muthgasse 18, 1190 Vienna, Austria
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13
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Zwiewka M, Bilanovičová V, Seifu YW, Nodzyński T. The Nuts and Bolts of PIN Auxin Efflux Carriers. FRONTIERS IN PLANT SCIENCE 2019; 10:985. [PMID: 31417597 PMCID: PMC6685051 DOI: 10.3389/fpls.2019.00985] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 07/12/2019] [Indexed: 05/20/2023]
Abstract
The plant-specific proteins named PIN-FORMED (PIN) efflux carriers facilitate the direction of auxin flow and thus play a vital role in the establishment of local auxin maxima within plant tissues that subsequently guide plant ontogenesis. They are membrane integral proteins with two hydrophobic regions consisting of alpha-helices linked with a hydrophilic loop, which is usually longer for the plasma membrane-localized PINs. The hydrophilic loop harbors molecular cues important for the subcellular localization and thus auxin efflux function of those transporters. The three-dimensional structure of PIN has not been solved yet. However, there are scattered but substantial data concerning the functional characterization of amino acid strings that constitute these carriers. These sequences include motifs vital for vesicular trafficking, residues regulating membrane diffusion, cellular polar localization, and activity of PINs. Here, we summarize those bits of information striving to provide a reference to structural motifs that have been investigated experimentally hoping to stimulate the efforts toward unraveling of PIN structure-function connections.
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Affiliation(s)
| | | | | | - Tomasz Nodzyński
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czechia
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Wang M, Qiao J, Yu C, Chen H, Sun C, Huang L, Li C, Geisler M, Qian Q, Jiang DA, Qi Y. The auxin influx carrier, OsAUX3, regulates rice root development and responses to aluminium stress. PLANT, CELL & ENVIRONMENT 2019; 42:1125-1138. [PMID: 30399648 DOI: 10.1111/pce.13478] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 10/25/2018] [Indexed: 05/06/2023]
Abstract
In rice, there are five members of the auxin carrier AUXIN1/LIKE AUX1 family; however, the biological functions of the other four members besides OsAUX1 remain unknown. Here, by using CRISPR/Cas9, we constructed two independent OsAUX3 knock-down lines, osaux3-1 and osaux3-2, in wild-type rice, Hwayoung (WT/HY) and Dongjin (WT/DJ). osaux3-1 and osaux3-2 have shorter primary roots (PRs), decreased lateral root (LR) density, and longer root hairs (RHs) compared with their WT. OsAUX3 expression in PRs, LRs, and RHs further supports that OsAUX3 plays a critical role in the regulation of root development. OsAUX3 locates at the plasma membrane and functions as an auxin influx carrier affecting acropetal auxin transport. OsAUX3 is up-regulated in the root apex under aluminium (Al) stress, and osaux3-2 is insensitive to Al treatments. Furthermore, 1-naphthylacetic acid accented the sensitivity of WT/DJ and osaux3-2 to respond to Al stress. Auxin concentrations, Al contents, and Al-induced reactive oxygen species-mediated damage in osaux3-2 under Al stress are lower than in WT, indicating that OsAUX3 is involved in Al-induced inhibition of root growth. This study uncovers a novel pathway alleviating Al-induced oxidative damage by inhibition of acropetal auxin transport and provides a new option for engineering Al-tolerant rice species.
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Affiliation(s)
- Mei Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - JiYue Qiao
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - ChenLiang Yu
- Vegetable Research Institute, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Hao Chen
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - ChenDong Sun
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - LinZhou Huang
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - ChuanYou Li
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Markus Geisler
- Department of Biology, University of Fribourg, Fribourg, CH-1700, Switzerland
| | - Qian Qian
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310006, China
| | - De An Jiang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - YanHua Qi
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
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15
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Di Mambro R, Svolacchia N, Dello Ioio R, Pierdonati E, Salvi E, Pedrazzini E, Vitale A, Perilli S, Sozzani R, Benfey PN, Busch W, Costantino P, Sabatini S. The Lateral Root Cap Acts as an Auxin Sink that Controls Meristem Size. Curr Biol 2019; 29:1199-1205.e4. [PMID: 30880016 DOI: 10.1016/j.cub.2019.02.022] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 12/27/2018] [Accepted: 02/06/2019] [Indexed: 12/28/2022]
Abstract
Plant developmental plasticity relies on the activities of meristems, regions where stem cells continuously produce new cells [1]. The lateral root cap (LRC) is the outermost tissue of the root meristem [1], and it is known to play an important role during root development [2-6]. In particular, it has been shown that mechanical or genetic ablation of LRC cells affect meristem size [7, 8]; however, the molecular mechanisms involved are unknown. Root meristem size and, consequently, root growth depend on the position of the transition zone (TZ), a boundary that separates dividing from differentiating cells [9, 10]. The interaction of two phytohormones, cytokinin and auxin, is fundamental in controlling the position of the TZ [9, 10]. Cytokinin via the ARABIDOPSIS RESPONSE REGULATOR 1 (ARR1) control auxin distribution within the meristem, generating an instructive auxin minimum that positions the TZ [10]. We identify a cytokinin-dependent molecular mechanism that acts in the LRC to control the position of the TZ and meristem size. We show that auxin levels within the LRC cells depends on PIN-FORMED 5 (PIN5), a cytokinin-activated intracellular transporter that pumps auxin from the cytoplasm into the endoplasmic reticulum, and on irreversible auxin conjugation mediated by the IAA-amino synthase GRETCHEN HAGEN 3.17 (GH3.17). By titrating auxin in the LRC, the PIN5 and the GH3.17 genes control auxin levels in the entire root meristem. Overall, our results indicate that the LRC serves as an auxin sink that, under the control of cytokinin, regulates meristem size and root growth.
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Affiliation(s)
- Riccardo Di Mambro
- Department of Biology, University of Pisa - via L. Ghini, 13 - 56126 Pisa, Italy.
| | - Noemi Svolacchia
- Dipartimento di Biologia e Biotecnologie, Laboratory of Functional Genomics and Proteomics of Model Systems, Università di Roma, Sapienza - via dei Sardi, 70 - 00185 Rome, Italy
| | - Raffaele Dello Ioio
- Dipartimento di Biologia e Biotecnologie, Laboratory of Functional Genomics and Proteomics of Model Systems, Università di Roma, Sapienza - via dei Sardi, 70 - 00185 Rome, Italy
| | - Emanuela Pierdonati
- Dipartimento di Biologia e Biotecnologie, Laboratory of Functional Genomics and Proteomics of Model Systems, Università di Roma, Sapienza - via dei Sardi, 70 - 00185 Rome, Italy
| | - Elena Salvi
- Dipartimento di Biologia e Biotecnologie, Laboratory of Functional Genomics and Proteomics of Model Systems, Università di Roma, Sapienza - via dei Sardi, 70 - 00185 Rome, Italy
| | - Emanuela Pedrazzini
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche - Via Alfonso Corti, 12 - 20133 Milano, Italy
| | - Alessandro Vitale
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche - Via Alfonso Corti, 12 - 20133 Milano, Italy
| | - Serena Perilli
- Dipartimento di Biologia e Biotecnologie, Laboratory of Functional Genomics and Proteomics of Model Systems, Università di Roma, Sapienza - via dei Sardi, 70 - 00185 Rome, Italy
| | - Rosangela Sozzani
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States
| | - Philip N Benfey
- Department of Biology and Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA
| | - Wolfgang Busch
- Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Paolo Costantino
- Dipartimento di Biologia e Biotecnologie, Laboratory of Functional Genomics and Proteomics of Model Systems, Università di Roma, Sapienza - via dei Sardi, 70 - 00185 Rome, Italy
| | - Sabrina Sabatini
- Dipartimento di Biologia e Biotecnologie, Laboratory of Functional Genomics and Proteomics of Model Systems, Università di Roma, Sapienza - via dei Sardi, 70 - 00185 Rome, Italy.
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16
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Feraru E, Feraru MI, Barbez E, Waidmann S, Sun L, Gaidora A, Kleine-Vehn J. PILS6 is a temperature-sensitive regulator of nuclear auxin input and organ growth in Arabidopsis thaliana. Proc Natl Acad Sci U S A 2019; 116:3893-3898. [PMID: 30755525 PMCID: PMC6397578 DOI: 10.1073/pnas.1814015116] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Temperature modulates growth and development throughout the entire lifecycle of a plant. High temperature (HT) triggers the auxin biosynthesis-dependent growth in aerial tissues. On the other hand, the contribution of auxin to HT-induced root growth is currently under debate. Here we show that the putative intracellular auxin carrier PIN-LIKES 6 (PILS6) is a negative regulator of organ growth and that its abundance is highly sensitive to HT. PILS6 localizes to the endoplasmic reticulum and limits the nuclear availability of auxin, consequently reducing the auxin signaling output. HT represses the PILS6 protein abundance, which impacts on PILS6-dependent auxin signaling in roots and root expansion. Accordingly, we hypothesize that PILS6 is part of an alternative mechanism linking HT to auxin responses in roots.
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Affiliation(s)
- Elena Feraru
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Mugurel I Feraru
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Elke Barbez
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Sascha Waidmann
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Lin Sun
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Angelika Gaidora
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Jürgen Kleine-Vehn
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
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17
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Skalický V, Kubeš M, Napier R, Novák O. Auxins and Cytokinins-The Role of Subcellular Organization on Homeostasis. Int J Mol Sci 2018; 19:E3115. [PMID: 30314316 PMCID: PMC6213326 DOI: 10.3390/ijms19103115] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/05/2018] [Accepted: 10/09/2018] [Indexed: 12/18/2022] Open
Abstract
Plant hormones are master regulators of plant growth and development. Better knowledge of their spatial signaling and homeostasis (transport and metabolism) on the lowest structural levels (cellular and subcellular) is therefore crucial to a better understanding of developmental processes in plants. Recent progress in phytohormone analysis at the cellular and subcellular levels has greatly improved the effectiveness of isolation protocols and the sensitivity of analytical methods. This review is mainly focused on homeostasis of two plant hormone groups, auxins and cytokinins. It will summarize and discuss their tissue- and cell-type specific distributions at the cellular and subcellular levels.
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Affiliation(s)
- Vladimír Skalický
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany of the Czech Academy of Sciences & Faculty of Science of Palacký University, Šlechtitelů 27, 78371 Olomouc, Czech Republic.
| | - Martin Kubeš
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science of Palacký University, Šlechtitelů 27, 78371 Olomouc, Czech Republic.
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK.
| | - Richard Napier
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK.
| | - Ondřej Novák
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany of the Czech Academy of Sciences & Faculty of Science of Palacký University, Šlechtitelů 27, 78371 Olomouc, Czech Republic.
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18
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Hu Y, Vandenbussche F, Van Der Straeten D. Regulation of seedling growth by ethylene and the ethylene-auxin crosstalk. PLANTA 2017; 245:467-489. [PMID: 28188422 DOI: 10.1007/s00425-017-2651-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 01/08/2017] [Indexed: 05/06/2023]
Abstract
This review highlights that the auxin gradient, established by local auxin biosynthesis and transport, can be controlled by ethylene, and steers seedling growth. A better understanding of the mechanisms in Arabidopsis will increase potential applications in crop species. In dark-grown Arabidopsis seedlings, exogenous ethylene treatment triggers an exaggeration of the apical hook, the inhibition of both hypocotyl and root elongation, and radial swelling of the hypocotyl. These features are predominantly based on the differential cell elongation in different cells/tissues mediated by an auxin gradient. Interestingly, the physiological responses regulated by ethylene and auxin crosstalk can be either additive or synergistic, as in primary root and root hair elongation, or antagonistic, as in hypocotyl elongation. This review focuses on the crosstalk of these two hormones at the seedling stage. Before illustrating the crosstalk, ethylene and auxin biosynthesis, metabolism, transport and signaling are briefly discussed.
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Affiliation(s)
- Yuming Hu
- Laboratory of Functional Plant Biology, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium
| | - Filip Vandenbussche
- Laboratory of Functional Plant Biology, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium
| | - Dominique Van Der Straeten
- Laboratory of Functional Plant Biology, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium.
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19
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Abstract
Microscope images of plant specimens showing expression of GUS markers, besides being very beautiful, provide useful information regarding various biological processes. However, the information extracted from these images is often purely qualitative, and in many publications is not subjected to quantification. Here, we describe a very simple quantification method for GUS histochemical staining that enables detection of subtle differences in gene expression at cellular, tissue, or organ level. The quantification method described is based on the freely available image analysis software ImageJ that is widely used by the scientific community. We exemplify the method by quantifying small and precise changes (at the cellular level) as well as broad changes (at the organ level) in the expression of two previously published reporter lines, such as the pPILS2::GUS and pPILS5::GUS. The method presented here represents an easy tool for converting visual information from GUS histochemical staining images into quantifiable data and is of general importance for plant biologists performing GUS activity-based evaluation of reporter genes.
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20
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Abstract
Glycosylation is essential for all trees of life. N-glycosylation is one of the most common covalent protein modifications and influences a large variety of cellular processes including protein folding, quality control and protein-receptor interactions. Despite recent progress in understanding of N-glycan biosynthesis, our knowledge of N-glycan function on individual plant proteins is still very limited. In this respect, plant hormone receptors are an interesting group of proteins as several of these proteins are present at distinct sites in the secretory pathway or at the plasma membrane and have numerous potential N-glycosylation sites. Identifying and characterization of N-glycan structures on these proteins is essential to investigate the functional role of this abundant protein modification. Here, a straightforward immunoblot-based approach is presented that enables the analysis of N-glycosylation on endogenous hormone receptors like the brassinosteroid receptor BRI1.
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Affiliation(s)
- Ulrike Vavra
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, BOKU, Muthgasse 18, 1190, Vienna, Austria
| | - Christiane Veit
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, BOKU, Muthgasse 18, 1190, Vienna, Austria
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, BOKU, Muthgasse 18, 1190, Vienna, Austria.
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21
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Liu F, Zhang L, Luo Y, Xu M, Fan Y, Wang L. Interactions of Oryza sativa OsCONTINUOUS VASCULAR RING-LIKE 1 (OsCOLE1) and OsCOLE1-INTERACTING PROTEIN reveal a novel intracellular auxin transport mechanism. THE NEW PHYTOLOGIST 2016; 212:96-107. [PMID: 27265035 DOI: 10.1111/nph.14021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 04/16/2016] [Indexed: 06/05/2023]
Abstract
Little is known about the transport mechanism of intracellular auxin. Here, we report two vacuole-localized proteins, Oryza sativa OsCONTINUOUS VASCULAR RING-LIKE 1 (OsCOLE1) and OsCOLE1-INTERACTING PROTEIN (OsCLIP), that regulate intracellular auxin transport and homoeostasis. Overexpression of OsCOLE1 markedly increased the internode length and auxin content of the stem base, whereas these parameters were decreased in RNA interference (RNAi) plants. OsCOLE1 was localized on the tonoplast and preferentially expressed in mature tissues. We further identified its interacting protein OsCLIP, which was co-localized on the tonoplast. Protein-protein binding assays demonstrated that the N-terminus of OsCOLE1 directly interacted with OsCLIP in yeast cells and the rice protoplast. Furthermore, (3) H-indole-3-acetic acid ((3) H-IAA) transport assays revealed that OsCLIP transported IAA into yeast cells, which was promoted by OsCOLE1. The results indicate that OsCOLE1 affects rice development by regulating intracellular auxin transport through interaction with OsCLIP, which provides a new insight into the regulatory mechanism of intracellular transport of auxin and the roles of vacuoles in plant development.
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Affiliation(s)
- Fei Liu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Haidian District, Beijing, China
| | - Lan Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Haidian District, Beijing, China
| | - Yanzhong Luo
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Haidian District, Beijing, China
| | - Miaoyun Xu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Haidian District, Beijing, China
| | - Yunliu Fan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Haidian District, Beijing, China
| | - Lei Wang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Haidian District, Beijing, China
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22
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Sanchez Carranza AP, Singh A, Steinberger K, Panigrahi K, Palme K, Dovzhenko A, Dal Bosco C. Hydrolases of the ILR1-like family of Arabidopsis thaliana modulate auxin response by regulating auxin homeostasis in the endoplasmic reticulum. Sci Rep 2016; 6:24212. [PMID: 27063913 PMCID: PMC4827090 DOI: 10.1038/srep24212] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 03/22/2016] [Indexed: 12/21/2022] Open
Abstract
Amide-linked conjugates of indole-3-acetic acid (IAA) have been identified in most plant species. They function in storage, inactivation or inhibition of the growth regulator auxin. We investigated how the major known endogenous amide-linked IAA conjugates with auxin-like activity act in auxin signaling and what role ILR1-like proteins play in this process in Arabidopsis. We used a genetically encoded auxin sensor to show that IAA-Leu, IAA-Ala and IAA-Phe act through the TIR1-dependent signaling pathway. Furthermore, by using the sensor as a free IAA reporter, we followed conjugate hydrolysis mediated by ILR1, ILL2 and IAR3 in plant cells and correlated the activity of the hydrolases with a modulation of auxin response. The conjugate preferences that we observed are in agreement with available in vitro data for ILR1. Moreover, we identified IAA-Leu as an additional substrate for IAR3 and showed that ILL2 has a more moderate kinetic performance than observed in vitro. Finally, we proved that IAR3, ILL2 and ILR1 reside in the endoplasmic reticulum, indicating that in this compartment the hydrolases regulate the rates of amido-IAA hydrolysis which results in activation of auxin signaling.
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Affiliation(s)
- Ana Paula Sanchez Carranza
- Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
| | - Aparajita Singh
- Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
| | - Karoline Steinberger
- Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
| | - Kishore Panigrahi
- National Institute of Science Education and Research, Institute of Physics Campus, Bhubaneswar, Odisha 751005, India
| | - Klaus Palme
- Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.,Freiburg Institute for Advanced Sciences (FRIAS), University of Freiburg, 79104 Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), University of Freiburg, 79104 Freiburg, Germany
| | - Alexander Dovzhenko
- Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
| | - Cristina Dal Bosco
- Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
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23
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Mittag J, Gabrielyan A, Ludwig-Müller J. Knockout of GH3 genes in the moss Physcomitrella patens leads to increased IAA levels at elevated temperature and in darkness. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2015; 97:339-49. [PMID: 26520677 DOI: 10.1016/j.plaphy.2015.10.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 10/05/2015] [Accepted: 10/07/2015] [Indexed: 05/21/2023]
Abstract
Two proteins of the GRETCHEN HAGEN3 (GH3) family of acyl acid amido synthetases from the moss Physcomitrella patens conjugate indole-3-acetic acid (IAA) to a series of amino acids. The possible function of altered auxin levels in the moss in response to two different growth perturbations, elevated temperatures and darkness, was analyzed using a) the recently described double knockout lines in both P. patens GH3 genes (GH3-doKO) and b) a previously characterized line harboring an auxin-inducible soybean GH3 promoter::reporter fused to β-glucuronidase (G1-GUS). The GUS activity as marker of the auxin response increased at higher temperatures and after cultivation in the darkness for a period of up to four weeks. Generally, the double knockout plants grew more slowly than the wild type (WT). The altered growth conditions influenced the phenotypes of the double knockout lines differently from that of WT moss. Higher temperatures negatively affected GH3-doKO plants compared to WT which was shown by stronger loss of chlorophyll. On the other hand, a positive effect was found on the concentrations of free IAA which increased at 28 °C in the GH3-doKO lines compared to WT plants. A different factor, namely darkness vs. a light/dark cycle caused the adverse phenotype concerning chlorophyll concentrations. Mutant moss plants showed higher chlorophyll concentrations than WT and these correlated with higher free IAA in the plant population that was classified as green. Our data show that growth perturbations result in higher free IAA levels in the GH3-doKO mutants, but in one case - growth in darkness - the mutants could cope better with the condition, whereas at elevated temperatures the mutants were more sensitive than WT. Thus, GH3 function in P. patens WT could lie in the regulation of IAA concentrations under unfavorable environmental conditions.
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Affiliation(s)
- Jennifer Mittag
- Institute of Botany, Technische Universität Dresden, 01062 Dresden, Germany
| | | | - Jutta Ludwig-Müller
- Institute of Botany, Technische Universität Dresden, 01062 Dresden, Germany.
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24
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Kriechbaumer V, Seo H, Park WJ, Hawes C. Endoplasmic reticulum localization and activity of maize auxin biosynthetic enzymes. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:6009-6020. [PMID: 26139824 DOI: 10.1093/jxb/erv314] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Auxin is a major growth hormone in plants and the first plant hormone to be discovered and studied. Active research over >60 years has shed light on many of the molecular mechanisms of its action including transport, perception, signal transduction, and a variety of biosynthetic pathways in various species, tissues, and developmental stages. The complexity and redundancy of the auxin biosynthetic network and enzymes involved raises the question of how such a system, producing such a potent agent as auxin, can be appropriately controlled at all. Here it is shown that maize auxin biosynthesis takes place in microsomal as well as cytosolic cellular fractions from maize seedlings. Most interestingly, a set of enzymes shown to be involved in auxin biosynthesis via their activity and/or mutant phenotypes and catalysing adjacent steps in YUCCA-dependent biosynthesis are localized to the endoplasmic reticulum (ER). Positioning of auxin biosynthetic enzymes at the ER could be necessary to bring auxin biosynthesis in closer proximity to ER-localized factors for transport, conjugation, and signalling, and allow for an additional level of regulation by subcellular compartmentation of auxin action. Furthermore, it might provide a link to ethylene action and be a factor in hormonal cross-talk as all five ethylene receptors are ER localized.
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Affiliation(s)
- Verena Kriechbaumer
- Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Hyesu Seo
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Yongin-si 448-701, South Korea
| | - Woong June Park
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Yongin-si 448-701, South Korea
| | - Chris Hawes
- Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
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25
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Robert HS, Crhak Khaitova L, Mroue S, Benková E. The importance of localized auxin production for morphogenesis of reproductive organs and embryos in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:5029-42. [PMID: 26019252 DOI: 10.1093/jxb/erv256] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Plant sexual reproduction involves highly structured and specialized organs: stamens (male) and gynoecia (female, containing ovules). These organs synchronously develop within protective flower buds, until anthesis, via tightly coordinated mechanisms that are essential for effective fertilization and production of viable seeds. The phytohormone auxin is one of the key endogenous signalling molecules controlling initiation and development of these, and other, plant organs. In particular, its uneven distribution, resulting from tightly controlled production, metabolism and directional transport, is an important morphogenic factor. In this review we discuss how developmentally controlled and localized auxin biosynthesis and transport contribute to the coordinated development of plants' reproductive organs, and their fertilized derivatives (embryos) via the regulation of auxin levels and distribution within and around them. Current understanding of the links between de novo local auxin biosynthesis, auxin transport and/or signalling is presented to highlight the importance of the non-cell autonomous action of auxin production on development and morphogenesis of reproductive organs and embryos. An overview of transcription factor families, which spatiotemporally define local auxin production by controlling key auxin biosynthetic enzymes, is also presented.
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Affiliation(s)
- Hélène S Robert
- Mendel Centre for Genomics and Proteomics of Plants Systems, CEITEC MU - Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic
| | - Lucie Crhak Khaitova
- Mendel Centre for Genomics and Proteomics of Plants Systems, CEITEC MU - Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic
| | - Souad Mroue
- Mendel Centre for Genomics and Proteomics of Plants Systems, CEITEC MU - Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic
| | - Eva Benková
- Institute of Science and Technology Austria (IST Austria), 3400 Klosterneuburg, Austria
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26
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Konrad SSA, Ott T. Molecular principles of membrane microdomain targeting in plants. TRENDS IN PLANT SCIENCE 2015; 20:351-61. [PMID: 25936559 DOI: 10.1016/j.tplants.2015.03.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 03/24/2015] [Accepted: 03/26/2015] [Indexed: 05/19/2023]
Abstract
Plasma membranes (PMs) are heterogeneous lipid bilayers comprising diverse subdomains. These sites can be labeled by various proteins in vivo and may serve as hotspots for signal transduction. They are found at apical, basal, and lateral membranes of polarized cells, at cell equatorial planes, or almost isotropically distributed throughout the PM. Recent advances in imaging technologies and understanding of mechanisms that allow proteins to target specific sites in PMs have provided insights into the dynamics and complexity of their specific segregation. Here we present a comprehensive overview of the different types of membrane microdomain and describe the molecular modes that determine site-directed targeting of membrane-resident proteins at the PM.
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Affiliation(s)
- Sebastian S A Konrad
- Ludwig-Maximilians-Universität München, Genetics, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
| | - Thomas Ott
- Ludwig-Maximilians-Universität München, Genetics, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany.
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27
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Feraru MI, Kleine-Vehn J, Feraru E. Auxin carrier and signaling dynamics during gravitropic root growth. Methods Mol Biol 2015; 1309:71-80. [PMID: 25981769 DOI: 10.1007/978-1-4939-2697-8_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Plant growth relates to gravity, ensuring that roots grow downwards into the soil and shoots expand aerially. The phytohormone auxin mediates tropistic growth responses, such as root gravitropism. Gravity perception in the very tip of the roots triggers carrier-dependent, asymmetric redistribution of auxin, leading to differential auxin responses and growth regulation at the upper and lower root flanks. This cellular, asymmetry-breaking event will eventually lead to root bending towards the gravity vector. Here, we show how to investigate auxin signaling and auxin carrier dynamics during root gravitropic response, using a chambered cover glass in combination with a confocal live cell imaging approach. To exemplify this method, we used established lines expressing transcriptional and translational green fluorescent protein (GFP) fusions to the auxin responsive promoter element DR5rev and the prominent auxin carrier PIN-FORMED2 (PIN2), respectively. Transgenic seedlings were placed and grown in the chambered cover glasses, enabling defined gravitropic stimulations prior to imaging. This method is optimal for inverted microscopes and significantly reduces stressful manipulations during specimen preparation.
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Affiliation(s)
- Mugurel I Feraru
- Department of Applied Genetics and Cell Biology (DAGZ), BOKU - University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190, Vienna, Austria
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28
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Abstract
Plants are permanently situated in a fixed location and thus are well adapted to sense and respond to environmental stimuli and developmental cues. At the cellular level, several of these responses require delicate adjustments that affect the activity and steady-state levels of plasma membrane proteins. These adjustments involve both vesicular transport to the plasma membrane and protein internalization via endocytic sorting. A substantial part of our current knowledge of plant plasma membrane protein sorting is based on studies of PIN-FORMED (PIN) auxin transport proteins, which are found at distinct plasma membrane domains and have been implicated in directional efflux of the plant hormone auxin. Here, we discuss the mechanisms involved in establishing such polar protein distributions, focusing on PINs and other key plant plasma membrane proteins, and we highlight the pathways that allow for dynamic adjustments in protein distribution and turnover, which together constitute a versatile framework that underlies the remarkable capabilities of plants to adjust growth and development in their ever-changing environment.
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Affiliation(s)
- Christian Luschnig
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, Vienna 1190, Austria
| | - Grégory Vert
- Institut des Sciences du Végétal, CNRS UPR 2355, 1 Avenue de la Terrasse, Bâtiment 23A, Gif-sur-Yvette 91190, France
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Balzan S, Johal GS, Carraro N. The role of auxin transporters in monocots development. FRONTIERS IN PLANT SCIENCE 2014; 5:393. [PMID: 25177324 PMCID: PMC4133927 DOI: 10.3389/fpls.2014.00393] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 07/23/2014] [Indexed: 05/04/2023]
Abstract
Auxin is a key regulator of plant growth and development, orchestrating cell division, elongation and differentiation, embryonic development, root and stem tropisms, apical dominance, and transition to flowering. Auxin levels are higher in undifferentiated cell populations and decrease following organ initiation and tissue differentiation. This differential auxin distribution is achieved by polar auxin transport (PAT) mediated by auxin transport proteins. There are four major families of auxin transporters in plants: PIN-FORMED (PIN), ATP-binding cassette family B (ABCB), AUXIN1/LIKE-AUX1s, and PIN-LIKES. These families include proteins located at the plasma membrane or at the endoplasmic reticulum (ER), which participate in auxin influx, efflux or both, from the apoplast into the cell or from the cytosol into the ER compartment. Auxin transporters have been largely studied in the dicotyledon model species Arabidopsis, but there is increasing evidence of their role in auxin regulated development in monocotyledon species. In monocots, families of auxin transporters are enlarged and often include duplicated genes and proteins with high sequence similarity. Some of these proteins underwent sub- and neo-functionalization with substantial modification to their structure and expression in organs such as adventitious roots, panicles, tassels, and ears. Most of the present information on monocot auxin transporters function derives from studies conducted in rice, maize, sorghum, and Brachypodium, using pharmacological applications (PAT inhibitors) or down-/up-regulation (over-expression and RNA interference) of candidate genes. Gene expression studies and comparison of predicted protein structures have also increased our knowledge of the role of PAT in monocots. However, knockout mutants and functional characterization of single genes are still scarce and the future availability of such resources will prove crucial to elucidate the role of auxin transporters in monocots development.
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Affiliation(s)
- Sara Balzan
- Department of Agronomy, Animals, Food, Natural Resources and Environment, Agripolis, University of PadovaPadova, Italy
| | - Gurmukh S. Johal
- Department of Botany and Plant Pathology, Purdue UniversityWest Lafayette, IN, USA
| | - Nicola Carraro
- Department of Agronomy, Purdue UniversityWest Lafayette, IN, USA
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Auxin transport sites are visualized in planta using fluorescent auxin analogs. Proc Natl Acad Sci U S A 2014; 111:11557-62. [PMID: 25049419 DOI: 10.1073/pnas.1408960111] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The plant hormone auxin is a key morphogenetic signal that controls many aspects of plant growth and development. Cellular auxin levels are coordinately regulated by multiple processes, including auxin biosynthesis and the polar transport and metabolic pathways. The auxin concentration gradient determines plant organ positioning and growth responses to environmental cues. Auxin transport systems play crucial roles in the spatiotemporal regulation of the auxin gradient. This auxin gradient has been analyzed using SCF-type E3 ubiquitin-ligase complex-based auxin biosensors in synthetic auxin-responsive reporter lines. However, the contributions of auxin biosynthesis and metabolism to the auxin gradient have been largely elusive. Additionally, the available information on subcellular auxin localization is still limited. Here we designed fluorescently labeled auxin analogs that remain active for auxin transport but are inactive for auxin signaling and metabolism. Fluorescent auxin analogs enable the selective visualization of the distribution of auxin by the auxin transport system. Together with auxin biosynthesis inhibitors and an auxin biosensor, these analogs indicated a substantial contribution of local auxin biosynthesis to the formation of auxin maxima at the root apex. Moreover, fluorescent auxin analogs mainly localized to the endoplasmic reticulum in cultured cells and roots, implying the presence of a subcellular auxin gradient in the cells. Our work not only provides a useful tool for the plant chemical biology field but also demonstrates a new strategy for imaging the distribution of small-molecule hormones.
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Retzer K, Butt H, Korbei B, Luschnig C. The far side of auxin signaling: fundamental cellular activities and their contribution to a defined growth response in plants. PROTOPLASMA 2014; 251:731-46. [PMID: 24221297 PMCID: PMC4059964 DOI: 10.1007/s00709-013-0572-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 10/15/2013] [Indexed: 05/04/2023]
Abstract
Recent years have provided us with spectacular insights into the biology of the plant hormone auxin, leaving the impression of a highly versatile molecule involved in virtually every aspect of plant development. A combination of genetics, biochemistry, and cell biology has established auxin signaling pathways, leading to the identification of two distinct modes of auxin perception and downstream regulatory cascades. Major targets of these signaling modules are components of the polar auxin transport machinery, mediating directional distribution of the phytohormone throughout the plant body, and decisively affecting plant development. Alterations in auxin transport, metabolism, or signaling that occur as a result of intrinsic as well as environmental stimuli, control adjustments in morphogenetic programs, giving rise to defined growth responses attributed to the activity of the phytohormone. Some of the results obtained from the analysis of auxin, however, do not fit coherently into a picture of highly specific signaling events, but rather suggest mutual interactions between auxin and fundamental cellular pathways, like the control of intracellular protein sorting or translation. Crosstalk between auxin and these basic determinants of cellular activity and how they might shape auxin effects in the control of morphogenesis are the subject of this review.
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Affiliation(s)
- Katarzyna Retzer
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, BOKU, Wien Muthgasse 18, 1190 Wien, Austria
| | - Haroon Butt
- Department of Biological Sciences, Forman Christian College, Ferozepur Road, Lahore, 54600 Pakistan
| | - Barbara Korbei
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, BOKU, Wien Muthgasse 18, 1190 Wien, Austria
| | - Christian Luschnig
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, BOKU, Wien Muthgasse 18, 1190 Wien, Austria
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Ranocha P, Dima O, Nagy R, Felten J, Corratgé-Faillie C, Novák O, Morreel K, Lacombe B, Martinez Y, Pfrunder S, Jin X, Renou JP, Thibaud JB, Ljung K, Fischer U, Martinoia E, Boerjan W, Goffner D. Arabidopsis WAT1 is a vacuolar auxin transport facilitator required for auxin homoeostasis. Nat Commun 2014; 4:2625. [PMID: 24129639 PMCID: PMC3826630 DOI: 10.1038/ncomms3625] [Citation(s) in RCA: 186] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 09/17/2013] [Indexed: 01/24/2023] Open
Abstract
The plant hormone auxin (indole-3-acetic acid, IAA) has a crucial role in plant development. Its spatiotemporal distribution is controlled by a combination of biosynthetic, metabolic and transport mechanisms. Four families of auxin transporters have been identified that mediate transport across the plasma or endoplasmic reticulum membrane. Here we report the discovery and the functional characterization of the first vacuolar auxin transporter. We demonstrate that WALLS ARE THIN1 (WAT1), a plant-specific protein that dictates secondary cell wall thickness of wood fibres, facilitates auxin export from isolated Arabidopsis vacuoles in yeast and in Xenopus oocytes. We unambiguously identify IAA and related metabolites in isolated Arabidopsis vacuoles, suggesting a key role for the vacuole in intracellular auxin homoeostasis. Moreover, local auxin application onto wat1 mutant stems restores fibre cell wall thickness. Our study provides new insight into the complexity of auxin transport in plants and a means to dissect auxin function during fibre differentiation.
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Affiliation(s)
- Philippe Ranocha
- 1] Université de Toulouse; UPS; UMR 5546, Laboratoire de Recherche en Sciences Végétales; BP 42617, F-31326, Castanet-Tolosan, France [2] Centre National de la Recherche Scientifique; CNRS; UMR5546; Laboratoire de Recherche en Sciences Végétales; BP 42617, F-31326, Castanet-Tolosan, France
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Pattison RJ, Csukasi F, Catalá C. Mechanisms regulating auxin action during fruit development. PHYSIOLOGIA PLANTARUM 2014; 151:62-72. [PMID: 24329770 DOI: 10.1111/ppl.12142] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 12/06/2013] [Accepted: 12/11/2013] [Indexed: 05/22/2023]
Abstract
Auxin controls many aspects of fruit development, including fruit set and growth, ripening and abscission. However, the mechanisms by which auxin regulates these processes are still poorly understood. While it is generally agreed that precise spatial and temporal control of auxin distribution and signaling are required for fruit development, the dynamics of auxin biosynthesis and the mechanisms for its transport to different fruit tissues are mostly unknown. Despite major advances in elucidating many aspects of auxin biology in vegetative tissues, until recently, the nature and importance of auxin metabolism, transport and signaling during fruit ontogeny remained obscure. In this review, we summarize recent research that has started to elucidate the molecular mechanisms by which auxin is produced and transported in the fruit and to unravel the complexity of auxin signaling during fruit development. We also discuss recent approaches used to reveal the genes and regulatory networks that mediate cell and tissue-specific control of auxin levels in the developing fruit.
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Ma Q, Robert S. Auxin biology revealed by small molecules. PHYSIOLOGIA PLANTARUM 2014; 151:25-42. [PMID: 24252105 DOI: 10.1111/ppl.12128] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 11/07/2013] [Accepted: 11/08/2013] [Indexed: 05/08/2023]
Abstract
The plant hormone auxin regulates virtually every aspect of plant growth and development and unraveling its molecular and cellular modes of action is fundamental for plant biology research. Chemical genomics is the use of small molecules to modify protein functions. This approach currently rises as a powerful technology for basic research. Small compounds with auxin-like activities or affecting auxin-mediated biological processes have been widely used in auxin research. They can serve as a tool complementary to genetic and genomic methods, facilitating the identification of an array of components modulating auxin metabolism, transport and signaling. The employment of high-throughput screening technologies combined with informatics-based chemical design and organic chemical synthesis has since yielded many novel small molecules with more instantaneous, precise and specific functionalities. By applying those small molecules, novel molecular targets can be isolated to further understand and dissect auxin-related pathways and networks that otherwise are too complex to be elucidated only by gene-based methods. Here, we will review examples of recently characterized molecules used in auxin research, highlight the strategies of unraveling the mechanisms of these small molecules and discuss future perspectives of small molecule applications in auxin biology.
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Affiliation(s)
- Qian Ma
- Umeå Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden
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35
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Nisar N, Cuttriss AJ, Pogson BJ, Cazzonelli CI. The promoter of the Arabidopsis PIN6 auxin transporter enabled strong expression in the vasculature of roots, leaves, floral stems and reproductive organs. PLANT SIGNALING & BEHAVIOR 2014; 9:e27898. [PMID: 24487186 PMCID: PMC4091377 DOI: 10.4161/psb.27898] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Cellular auxin homeostasis controls many aspects of plant growth, organogenesis and development. The existence of intracellular auxin transport mediated by endoplasmic reticulum (ER)-localized PIN5, PIN6 and PIN8 proteins is a relatively recent discovery shaping a new era in understanding auxin-mediated growth processes. Here we summarize the importance of PIN6 in mediating intracellular auxin transport during root formation, leaf vein patterning and nectary production. While, it was previously shown that PIN6 was strongly expressed in rosette leaf cell types important in vein formation, here we demonstrate by use a PIN6 promoter-reporter fusion, that PIN6 is also preferentially expressed in the vasculature of the primary root, cotyledons, cauline leaves, floral stem, sepals and the main transmitting tract of the reproductive silique. The strong, vein- specific reporter gene expression patterns enabled by the PIN6 promoter emphasizes that transcriptional control is likely to be a major regulator of PIN6 protein levels, during vasculature formation, and supports the need for ER-localized PIN proteins in selecting specialized cells for vascular function in land plants.
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36
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Morozov SY, Makarova SS, Erokhina TN, Kopertekh L, Schiemann J, Owens RA, Solovyev AG. Plant 4/1 protein: potential player in intracellular, cell-to-cell and long-distance signaling. FRONTIERS IN PLANT SCIENCE 2014; 5:26. [PMID: 24611067 PMCID: PMC3933784 DOI: 10.3389/fpls.2014.00026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 01/22/2014] [Indexed: 05/09/2023]
Abstract
Originally isolated as a result of its ability to interact with the movement protein of Tomato spotted wilt virus in a yeast two-hybrid system, the 4/1 protein is proving to be an excellent tool for studying intracellular protein trafficking and intercellular communication. Expression of 4/1 in vivo is tightly regulated, first appearing in the veins of the cotyledon and later in the vasculature of the leaf and stem in association with the xylem parenchyma and phloem parenchyma. Structural studies indicate that 4/1 proteins contain as many as five coiled-coil (CC) domains; indeed, the highest level of sequence identity among 4/1 proteins involves their C-terminal CC domains, suggesting that protein-protein interaction is important for biological function. Recent data predict that the tertiary structure of this C-terminal CC domain is strikingly similar to that of yeast protein She2p; furthermore, like She2p, 4/1 protein exhibits RNA-binding activity, and mutational analysis has shown that the C-terminal CC domain is responsible for RNA binding. The 4/1 protein contains a nuclear export signal. Additional microscopy studies involving leptomycin and computer prediction suggest the presence of a nuclear localization signal as well.
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Affiliation(s)
- Sergey Y. Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State UniversityMoscow, Russia
- *Correspondence: Sergey Y. Morozov, A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia e-mail:
| | - Svetlana S. Makarova
- Department of Virology, Faculty of Biology, Moscow State UniversityMoscow, Russia
| | - Tatyana N. Erokhina
- M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of SciencesMoscow, Russia
| | - Lilya Kopertekh
- Biosafety in Plant Biotechnology, Julius Kühn Institute – Federal Research Centre for Cultivated PlantsQuedlinburg, Germany
| | - Joachim Schiemann
- Biosafety in Plant Biotechnology, Julius Kühn Institute – Federal Research Centre for Cultivated PlantsQuedlinburg, Germany
| | | | - Andrey G. Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State UniversityMoscow, Russia
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37
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Abstract
Auxin is a plant hormone involved in an extraordinarily broad variety of biological mechanisms. These range from basic cellular processes, such as endocytosis, cell polarity, and cell cycle control over localized responses such as cell elongation and differential growth, to macroscopic phenomena such as embryogenesis, tissue patterning, and de novo formation of organs. Even though the history of auxin research reaches back more than a hundred years, we are still far from a comprehensive understanding of how auxin governs such a wide range of responses. Some answers to this question may lie in the auxin molecule itself. Naturally occurring auxin-like substances have been found and they may play roles in specific developmental and cellular processes. The molecular mode of auxin action can be further explored by the utilization of synthetic auxin-like molecules. A second area is the perception of auxin, where we know of three seemingly independent receptors and signalling systems, some better understood than others, but each of them probably involved in distinct physiological processes. Lastly, auxin is actively modified, metabolized, and intracellularly compartmentalized, which can have a great impact on its availability and activity. In this review, we will give an overview of these rather recent and emerging areas of auxin research and try to formulate some of the open questions. Without doubt, the manifold facets of auxin biology will not cease to amaze us for a long time to come.
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Affiliation(s)
- Michael Sauer
- Centro Nacional de Biotecnología-CNB-CSIC, Darwin 3, 28049 Madrid, Spain
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Barbez E, Laňková M, Pařezová M, Maizel A, Zažímalová E, Petrášek J, Friml J, Kleine-Vehn J. Single-cell-based system to monitor carrier driven cellular auxin homeostasis. BMC PLANT BIOLOGY 2013; 13:20. [PMID: 23379388 PMCID: PMC3598821 DOI: 10.1186/1471-2229-13-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 01/31/2013] [Indexed: 05/06/2023]
Abstract
BACKGROUND Abundance and distribution of the plant hormone auxin play important roles in plant development. Besides other metabolic processes, various auxin carriers control the cellular level of active auxin and, hence, are major regulators of cellular auxin homeostasis. Despite the developmental importance of auxin transporters, a simple medium-to-high throughput approach to assess carrier activities is still missing. Here we show that carrier driven depletion of cellular auxin correlates with reduced nuclear auxin signaling in tobacco Bright Yellow-2 (BY-2) cell cultures. RESULTS We developed an easy to use transient single-cell-based system to detect carrier activity. We use the relative changes in signaling output of the auxin responsive promoter element DR5 to indirectly visualize auxin carrier activity. The feasibility of the transient approach was demonstrated by pharmacological and genetic interference with auxin signaling and transport. As a proof of concept, we provide visual evidence that the prominent auxin transport proteins PIN-FORMED (PIN)2 and PIN5 regulate cellular auxin homeostasis at the plasma membrane and endoplasmic reticulum (ER), respectively. Our data suggest that PIN2 and PIN5 have different sensitivities to the auxin transport inhibitor 1-naphthylphthalamic acid (NPA). Also the putative PIN-LIKES (PILS) auxin carrier activity at the ER is insensitive to NPA in our system, indicating that NPA blocks intercellular, but not intracellular auxin transport. CONCLUSIONS This single-cell-based system is a useful tool by which the activity of putative auxin carriers, such as PINs, PILS and WALLS ARE THIN1 (WAT1), can be indirectly visualized in a medium-to-high throughput manner. Moreover, our single cell system might be useful to investigate also other hormonal signaling pathways, such as cytokinin.
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Affiliation(s)
- Elke Barbez
- Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and Genetics, Ghent University, 9052, Gent, Belgium
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), 1190, Vienna, Austria
| | - Martina Laňková
- Institute of Experimental Botany, The Academy of Sciences of the Czech Republic, 16502, Praha 6, Czech Republic
| | - Markéta Pařezová
- Institute of Experimental Botany, The Academy of Sciences of the Czech Republic, 16502, Praha 6, Czech Republic
| | - Alexis Maizel
- Department of Stem Cell Biology, Center for Organismal Studies, University of Heidelberg, 69120, Heidelberg, Germany
| | - Eva Zažímalová
- Institute of Experimental Botany, The Academy of Sciences of the Czech Republic, 16502, Praha 6, Czech Republic
| | - Jan Petrášek
- Institute of Experimental Botany, The Academy of Sciences of the Czech Republic, 16502, Praha 6, Czech Republic
| | - Jiří Friml
- Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and Genetics, Ghent University, 9052, Gent, Belgium
- Department of Functional Genomics and Proteomics, Faculty of Science, and CEITEC, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Jürgen Kleine-Vehn
- Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and Genetics, Ghent University, 9052, Gent, Belgium
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), 1190, Vienna, Austria
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