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Fukui K, Hayashi KI. Manipulation and Sensing of Auxin Metabolism, Transport and Signaling. PLANT & CELL PHYSIOLOGY 2018; 59:1500-1510. [PMID: 29668988 DOI: 10.1093/pcp/pcy076] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/09/2018] [Indexed: 05/26/2023]
Abstract
The plant hormone auxin is involved in virtually every aspect of plant growth and development. A chemical genetic approach has greatly contributed to the identification of important genes in auxin biosynthesis, transport and signaling. Molecular genetic technologies and structural information for auxin regulatory components have accelerated the identification and characterization of many novel small molecule modulators in auxin biology. These modulators have been widely utilized to dissect auxin responses. Here we provide an overview of the structure, primary target, in planta activity and application of small molecule modulators in auxin biology.
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Affiliation(s)
- Kosuke Fukui
- Department of Biochemistry, Okayama University of Science, Okayama City, Japan
| | - Ken-Ichiro Hayashi
- Department of Biochemistry, Okayama University of Science, Okayama City, Japan
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52
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Ishimaru Y, Hayashi K, Suzuki T, Fukaki H, Prusinska J, Meester C, Quareshy M, Egoshi S, Matsuura H, Takahashi K, Kato N, Kombrink E, Napier RM, Hayashi KI, Ueda M. Jasmonic Acid Inhibits Auxin-Induced Lateral Rooting Independently of the CORONATINE INSENSITIVE1 Receptor. PLANT PHYSIOLOGY 2018; 177:1704-1716. [PMID: 29934297 PMCID: PMC6084677 DOI: 10.1104/pp.18.00357] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 06/13/2018] [Indexed: 05/23/2023]
Abstract
Plant root systems are indispensable for water uptake, nutrient acquisition, and anchoring plants in the soil. Previous studies using auxin inhibitors definitively established that auxin plays a central role regulating root growth and development. Most auxin inhibitors affect all auxin signaling at the same time, which obscures an understanding of individual events. Here, we report that jasmonic acid (JA) functions as a lateral root (LR)-preferential auxin inhibitor in Arabidopsis (Arabidopsis thaliana) in a manner that is independent of the JA receptor, CORONATINE INSENSITIVE1 (COI1). Treatment of wild-type Arabidopsis with either (-)-JA or (+)-JA reduced primary root length and LR number; the reduction of LR number was also observed in coi1 mutants. Treatment of seedlings with (-)-JA or (+)-JA suppressed auxin-inducible genes related to LR formation, diminished accumulation of the auxin reporter DR5::GUS, and inhibited auxin-dependent DII-VENUS degradation. A structural mimic of (-)-JA and (+)-coronafacic acid also inhibited LR formation and stabilized DII-VENUS protein. COI1-independent activity was retained in the double mutant of transport inhibitor response1 and auxin signaling f-box protein2 (tir1 afb2) but reduced in the afb5 single mutant. These results reveal JAs and (+)-coronafacic acid to be selective counter-auxins, a finding that could lead to new approaches for studying the mechanisms of LR formation.
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Affiliation(s)
- Yasuhiro Ishimaru
- Department of Chemistry, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Kengo Hayashi
- Department of Chemistry, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Takeshi Suzuki
- Department of Chemistry, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Hidehiro Fukaki
- Department of Biology, Kobe University, Kobe 657-8501, Japan
| | - Justyna Prusinska
- School of Life Sciences, University of Warwick, Warwickshire CV4 7AS, United Kingdom
| | - Christian Meester
- Chemical Biology Laboratory, Max Planck Institute for Plant Breeding Research, D-50829 Cologne, Germany
| | - Mussa Quareshy
- School of Life Sciences, University of Warwick, Warwickshire CV4 7AS, United Kingdom
| | - Syusuke Egoshi
- Department of Chemistry, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Hideyuki Matsuura
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Kosaku Takahashi
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Nobuki Kato
- Department of Chemistry, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Erich Kombrink
- Chemical Biology Laboratory, Max Planck Institute for Plant Breeding Research, D-50829 Cologne, Germany
| | - Richard M Napier
- School of Life Sciences, University of Warwick, Warwickshire CV4 7AS, United Kingdom
| | - Ken-Ichiro Hayashi
- Department of Biochemistry, Okayama University of Science, Okayama 700-0005, Japan
| | - Minoru Ueda
- Department of Chemistry, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
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53
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Dyer WE. Stress-induced evolution of herbicide resistance and related pleiotropic effects. PEST MANAGEMENT SCIENCE 2018; 74:1759-1768. [PMID: 29688592 DOI: 10.1002/ps.5043] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 04/13/2018] [Accepted: 04/14/2018] [Indexed: 05/11/2023]
Abstract
Herbicide-resistant weeds, especially those with resistance to multiple herbicides, represent a growing worldwide threat to agriculture and food security. Natural selection for resistant genotypes may act on standing genetic variation, or on a genetic and physiological background that is fundamentally altered because of stress responses to sublethal herbicide exposure. Stress-induced changes include DNA mutations, epigenetic alterations, transcriptional remodeling, and protein modifications, all of which can lead to herbicide resistance and a wide range of pleiotropic effects. Resistance selected in this manner is termed systemic acquired herbicide resistance, and the associated pleiotropic effects are manifested as a suite of constitutive transcriptional and post-translational changes related to biotic and abiotic stress adaptation, representing the evolutionary signature of selection. This phenotype is being investigated in two multiple herbicide-resistant populations of the hexaploid, self-pollinating weedy monocot Avena fatua that display such changes as well as constitutive reductions in certain heat shock proteins and their transcripts, which are well known as global regulators of diverse stress adaptation pathways. Herbicide-resistant populations of most weedy plant species exhibit pleiotropic effects, and their association with resistance genes presents a fertile area of investigation. This review proposes that more detailed studies of resistant A. fatua and other species through the lens of plant evolution under stress will inform improved resistant weed prevention and management strategies. © 2018 Society of Chemical Industry.
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Affiliation(s)
- William Edward Dyer
- Department of Plant Sciences & Plant Pathology, Montana State University, Bozeman, MT, USA
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54
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Cross-resistance to dicamba, 2,4-D, and fluroxypyr in Kochia scoparia is endowed by a mutation in an AUX/IAA gene. Proc Natl Acad Sci U S A 2018. [PMID: 29531066 DOI: 10.1073/pnas.1712372115] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The understanding and mitigation of the appearance of herbicide-resistant weeds have come to the forefront of study in the past decade, as the number of weed species that are resistant to one or more herbicide modes of action is on the increase. Historically, weed resistance to auxin herbicides has been rare, but examples, such as Kochia scoparia L. Schrad (kochia), have appeared, posing a challenge to conventional agricultural practices. Reports of dicamba-resistant kochia populations began in the early 1990s in areas where auxin herbicides were heavily utilized for weed control in corn and wheat cropping systems, and some biotypes are resistant to other auxin herbicides as well. We have further characterized the auxin responses of one previously reported dicamba-resistant biotype isolated from western Nebraska and found that it is additionally cross-resistant to other auxin herbicides, including 2,4-dichlorophenoxyacetic acid (2,4-D) and fluroxypyr. We have utilized transcriptome sequencing and comparison to identify a 2-nt base change in this biotype, which results in a glycine to asparagine amino acid change within a highly conserved region of an AUX/indole-3-acetic acid (IAA) protein, KsIAA16. Through yeast two-hybrid analysis, characterization of F2 segregation, and heterologous expression and characterization of the gene in Arabidopsis thaliana, we show that that the single dominant KsIAA16R resistance allele is the causal basis for dicamba resistance in this population. Furthermore, we report the development of a molecular marker to identify this allele in populations and facilitate inheritance studies. We also report that the resistance allele confers a fitness penalty in greenhouse studies.
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55
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Ma Q, Grones P, Robert S. Auxin signaling: a big question to be addressed by small molecules. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:313-328. [PMID: 29237069 PMCID: PMC5853230 DOI: 10.1093/jxb/erx375] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 10/16/2017] [Indexed: 05/20/2023]
Abstract
Providing a mechanistic understanding of the crucial roles of the phytohormone auxin has been an important and coherent aspect of plant biology research. Since its discovery more than a century ago, prominent advances have been made in the understanding of auxin action, ranging from metabolism and transport to cellular and transcriptional responses. However, there is a long road ahead before a thorough understanding of its complex effects is achieved, because a lot of key information is still missing. The availability of an increasing number of technically advanced scientific tools has boosted the basic discoveries in auxin biology. A plethora of bioactive small molecules, consisting of the synthetic auxin-like herbicides and the more specific auxin-related compounds, developed as a result of the exploration of chemical space by chemical biology, have made the tool box for auxin research more comprehensive. This review mainly focuses on the compounds targeting the auxin co-receptor complex, demonstrates the various ways to use them, and shows clear examples of important basic knowledge obtained by their usage. Application of these precise chemical tools, together with an increasing amount of structural information for the major components in auxin action, will certainly aid in strengthening our insights into the complexity and diversity of auxin response.
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Affiliation(s)
- Qian Ma
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Sweden
| | - Peter Grones
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Sweden
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56
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Kato H, Nishihama R, Weijers D, Kohchi T. Evolution of nuclear auxin signaling: lessons from genetic studies with basal land plants. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:291-301. [PMID: 28992186 DOI: 10.1093/jxb/erx267] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Auxin plays critical roles in growth and development through the regulation of cell differentiation, cell expansion, and pattern formation. The auxin signal is mainly conveyed through a so-called nuclear auxin pathway involving the receptor TIR1/AFB, the transcriptional co-repressor AUX/IAA, and the transcription factor ARF with direct DNA-binding ability. Recent progress in sequence information and molecular genetics in basal plants has provided many insights into the evolutionary origin of the nuclear auxin pathway and its pleiotropic roles in land plant development. In this review, we summarize the latest knowledge of the nuclear auxin pathway gained from studies using basal plants, including charophycean green algae and two major model bryophytes, Marchantia polymorpha and Physcomitrella patens. In addition, we discuss the functional implication of the increase in genetic complexity of the nuclear auxin pathway during land plant evolution.
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Affiliation(s)
- Hirotaka Kato
- Laboratory of Biochemistry, Wageningen University, The Netherlands
| | | | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, The Netherlands
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57
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Abstract
Auxin triggers diverse responses in plants, and this is reflected in quantitative and qualitative diversity in the auxin signaling machinery.
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Affiliation(s)
- Ottoline Leyser
- Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, United Kingdom
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58
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Bagchi R, Melnyk CW, Christ G, Winkler M, Kirchsteiner K, Salehin M, Mergner J, Niemeyer M, Schwechheimer C, Calderón Villalobos LIA, Estelle M. The Arabidopsis ALF4 protein is a regulator of SCF E3 ligases. EMBO J 2017; 37:255-268. [PMID: 29233834 DOI: 10.15252/embj.201797159] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 11/10/2017] [Accepted: 11/16/2017] [Indexed: 12/21/2022] Open
Abstract
The cullin-RING E3 ligases (CRLs) regulate diverse cellular processes in all eukaryotes. CRL activity is controlled by several proteins or protein complexes, including NEDD8, CAND1, and the CSN Recently, a mammalian protein called Glomulin (GLMN) was shown to inhibit CRLs by binding to the RING BOX (RBX1) subunit and preventing binding to the ubiquitin-conjugating enzyme. Here, we show that Arabidopsis ABERRANT LATERAL ROOT FORMATION4 (ALF4) is an ortholog of GLMN The alf4 mutant exhibits a phenotype that suggests defects in plant hormone response. We show that ALF4 binds to RBX1 and inhibits the activity of SCFTIR1, an E3 ligase responsible for degradation of the Aux/IAA transcriptional repressors. In vivo, the alf4 mutation destabilizes the CUL1 subunit of the SCF Reduced CUL1 levels are associated with increased levels of the Aux/IAA proteins as well as the DELLA repressors, substrate of SCFSLY1 We propose that the alf4 phenotype is partly due to increased levels of the Aux/IAA and DELLA proteins.
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Affiliation(s)
- Rammyani Bagchi
- Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA, USA
| | | | - Gideon Christ
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry, Halle, Germany
| | - Martin Winkler
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry, Halle, Germany.,Institute of Biology, Structural Biology/Biochemistry, Humboldt-University Berlin, Berlin, Germany
| | - Kerstin Kirchsteiner
- Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA, USA
| | - Mohammad Salehin
- Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA, USA
| | - Julia Mergner
- Plant Systems Biology, Technische Universität München, Freising, Germany
| | - Michael Niemeyer
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry, Halle, Germany
| | | | | | - Mark Estelle
- Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA, USA
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59
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Ligerot Y, de Saint Germain A, Waldie T, Troadec C, Citerne S, Kadakia N, Pillot JP, Prigge M, Aubert G, Bendahmane A, Leyser O, Estelle M, Debellé F, Rameau C. The pea branching RMS2 gene encodes the PsAFB4/5 auxin receptor and is involved in an auxin-strigolactone regulation loop. PLoS Genet 2017; 13:e1007089. [PMID: 29220348 PMCID: PMC5738142 DOI: 10.1371/journal.pgen.1007089] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 12/20/2017] [Accepted: 10/30/2017] [Indexed: 12/31/2022] Open
Abstract
Strigolactones (SLs) are well known for their role in repressing shoot branching. In pea, increased transcript levels of SL biosynthesis genes are observed in stems of highly branched SL deficient (ramosus1 (rms1) and rms5) and SL response (rms3 and rms4) mutants indicative of negative feedback control. In contrast, the highly branched rms2 mutant has reduced transcript levels of SL biosynthesis genes. Grafting studies and hormone quantification led to a model where RMS2 mediates a shoot-to-root feedback signal that regulates both SL biosynthesis gene transcript levels and xylem sap levels of cytokinin exported from roots. Here we cloned RMS2 using synteny with Medicago truncatula and demonstrated that it encodes a putative auxin receptor of the AFB4/5 clade. Phenotypes similar to rms2 were found in Arabidopsis afb4/5 mutants, including increased shoot branching, low expression of SL biosynthesis genes and high auxin levels in stems. Moreover, afb4/5 and rms2 display a specific resistance to the herbicide picloram. Yeast-two-hybrid experiments supported the hypothesis that the RMS2 protein functions as an auxin receptor. SL root feeding using hydroponics repressed auxin levels in stems and down-regulated transcript levels of auxin biosynthesis genes within one hour. This auxin down-regulation was also observed in plants treated with the polar auxin transport inhibitor NPA. Together these data suggest a homeostatic feedback loop in which auxin up-regulates SL synthesis in an RMS2-dependent manner and SL down-regulates auxin synthesis in an RMS3 and RMS4-dependent manner.
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Affiliation(s)
- Yasmine Ligerot
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
- Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | | | - Tanya Waldie
- Sainsbury Laboratory Cambridge University, Bateman Street, Cambridge, United Kingdom
| | - Christelle Troadec
- Institute of Plant Sciences Paris-Saclay, INRA, CNRS, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Orsay, France
| | - Sylvie Citerne
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Nikita Kadakia
- Howard Hughes Medical Institute and Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California, United States of America
| | - Jean-Paul Pillot
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Michael Prigge
- Howard Hughes Medical Institute and Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California, United States of America
| | - Grégoire Aubert
- Agroécologie, AgroSup Dijon, INRA, Université Bourgogne Franche-Comté, Dijon, France
| | - Abdelhafid Bendahmane
- Institute of Plant Sciences Paris-Saclay, INRA, CNRS, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Orsay, France
| | - Ottoline Leyser
- Sainsbury Laboratory Cambridge University, Bateman Street, Cambridge, United Kingdom
| | - Mark Estelle
- Howard Hughes Medical Institute and Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California, United States of America
| | - Frédéric Debellé
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Catherine Rameau
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
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60
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Olatunji D, Geelen D, Verstraeten I. Control of Endogenous Auxin Levels in Plant Root Development. Int J Mol Sci 2017; 18:E2587. [PMID: 29194427 PMCID: PMC5751190 DOI: 10.3390/ijms18122587] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 11/26/2017] [Accepted: 11/28/2017] [Indexed: 12/24/2022] Open
Abstract
In this review, we summarize the different biosynthesis-related pathways that contribute to the regulation of endogenous auxin in plants. We demonstrate that all known genes involved in auxin biosynthesis also have a role in root formation, from the initiation of a root meristem during embryogenesis to the generation of a functional root system with a primary root, secondary lateral root branches and adventitious roots. Furthermore, the versatile adaptation of root development in response to environmental challenges is mediated by both local and distant control of auxin biosynthesis. In conclusion, auxin homeostasis mediated by spatial and temporal regulation of auxin biosynthesis plays a central role in determining root architecture.
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Affiliation(s)
- Damilola Olatunji
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Gent, Belgium.
| | - Danny Geelen
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Gent, Belgium.
| | - Inge Verstraeten
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Gent, Belgium.
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria.
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61
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Wright RC, Zahler ML, Gerben SR, Nemhauser JL. Insights into the Evolution and Function of Auxin Signaling F-Box Proteins in Arabidopsis thaliana Through Synthetic Analysis of Natural Variants. Genetics 2017; 207:583-591. [PMID: 28760746 PMCID: PMC5629325 DOI: 10.1534/genetics.117.300092] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 07/24/2017] [Indexed: 12/20/2022] Open
Abstract
The evolution of complex body plans in land plants has been paralleled by gene duplication and divergence within nuclear auxin-signaling networks. A deep mechanistic understanding of auxin signaling proteins therefore may allow rational engineering of novel plant architectures. Toward that end, we analyzed natural variation in the auxin receptor F-box family of wild accessions of the reference plant Arabidopsis thaliana and used this information to populate a structure/function map. We employed a synthetic assay to identify natural hypermorphic F-box variants and then assayed auxin-associated phenotypes in accessions expressing these variants. To more directly measure the impact of the strongest variant in our synthetic assay on auxin sensitivity, we generated transgenic plants expressing this allele. Together, our findings link evolved sequence variation to altered molecular performance and auxin sensitivity. This approach demonstrates the potential for combining synthetic biology approaches with quantitative phenotypes to harness the wealth of available sequence information and guide future engineering efforts of diverse signaling pathways.
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Affiliation(s)
- R Clay Wright
- Department of Biology, University of Washington, Seattle, Washington 98195-1800
| | - Mollye L Zahler
- Department of Biology, University of Washington, Seattle, Washington 98195-1800
| | - Stacey R Gerben
- Department of Biology, University of Washington, Seattle, Washington 98195-1800
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62
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Xu J, Li J, Cui L, Zhang T, Wu Z, Zhu PY, Meng YJ, Zhang KJ, Yu XQ, Lou QF, Chen JF. New insights into the roles of cucumber TIR1 homologs and miR393 in regulating fruit/seed set development and leaf morphogenesis. BMC PLANT BIOLOGY 2017; 17:130. [PMID: 28747179 PMCID: PMC5530481 DOI: 10.1186/s12870-017-1075-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 07/13/2017] [Indexed: 05/04/2023]
Abstract
BACKGROUND TIR1-like proteins act as auxin receptors and play essential roles in auxin-mediated plant development processes. The number of auxin receptor family members varies among species. While the functions of auxin receptor genes have been widely studied in Arabidopsis, the distinct functions of cucumber (Cucumis sativus L.) auxin receptors remains poorly understood. To further our understanding of their potential role in cucumber development, two TIR1-like genes were identified and designated CsTIR1 and CsAFB2. In the present study, tomato (Sonanum lycopersicum) was used as a model to investigate the phenotypic and molecular changes associated with the overexpression of CsTIR1 and CsAFB2. RESULTS Differences in the subcellular localizations of CsTIR1 and CsAFB2 were identified and both genes were actively expressed in leaf, female flower and young fruit tissues of cucumber. Moreover, CsTIR1- and CsAFB2-overexpressing lines exhibited pleotropic phenotypes ranging from leaf abnormalities to seed germination and parthenocarpic fruit compared with the wild-type plants. To further elucidate the regulation of CsTIR1 and CsAFB2, the role of the miR393/TIR1 module in regulating cucumber fruit set were investigated. Activation of miR393-mediated mRNA cleavage of CsTIR1 and CsAFB2 was revealed by qPCR and semi-qPCR, which highlighted the critical role of the miR393/TIR1 module in mediating fruit set development in cucumber. CONCLUSION Our results provide new insights into the involvement of CsTIR1 and CsAFB2 in regulating various phenotype alterations, and suggest that post-transcriptional regulation of CsTIR1 and CsAFB2 mediated by miR393 is essential for cucumber fruit set initiation. Collectively, these results further clarify the roles of cucumber TIR1 homologs and miR393 in regulating fruit/seed set development and leaf morphogenesis.
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Affiliation(s)
- Jian Xu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Ji Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Li Cui
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Ting Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Zhe Wu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Pin-Yu Zhu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Yong-Jiao Meng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Kai-Jing Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Xia-Qing Yu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Qun-Feng Lou
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Jin-Feng Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
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63
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Hu Y, Depaepe T, Smet D, Hoyerova K, Klíma P, Cuypers A, Cutler S, Buyst D, Morreel K, Boerjan W, Martins J, Petrášek J, Vandenbussche F, Van Der Straeten D. ACCERBATIN, a small molecule at the intersection of auxin and reactive oxygen species homeostasis with herbicidal properties. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:4185-4203. [PMID: 28922768 PMCID: PMC5853866 DOI: 10.1093/jxb/erx242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 06/22/2017] [Indexed: 05/30/2023]
Abstract
The volatile two-carbon hormone ethylene acts in concert with an array of signals to affect etiolated seedling development. From a chemical screen, we isolated a quinoline carboxamide designated ACCERBATIN (AEX) that exacerbates the 1-aminocyclopropane-1-carboxylic acid-induced triple response, typical for ethylene-treated seedlings in darkness. Phenotypic analyses revealed distinct AEX effects including inhibition of root hair development and shortening of the root meristem. Mutant analysis and reporter studies further suggested that AEX most probably acts in parallel to ethylene signaling. We demonstrated that AEX functions at the intersection of auxin metabolism and reactive oxygen species (ROS) homeostasis. AEX inhibited auxin efflux in BY-2 cells and promoted indole-3-acetic acid (IAA) oxidation in the shoot apical meristem and cotyledons of etiolated seedlings. Gene expression studies and superoxide/hydrogen peroxide staining further revealed that the disrupted auxin homeostasis was accompanied by oxidative stress. Interestingly, in light conditions, AEX exhibited properties reminiscent of the quinoline carboxylate-type auxin-like herbicides. We propose that AEX interferes with auxin transport from its major biosynthesis sites, either as a direct consequence of poor basipetal transport from the shoot meristematic region, or indirectly, through excessive IAA oxidation and ROS accumulation. Further investigation of AEX can provide new insights into the mechanisms connecting auxin and ROS homeostasis in plant development and provide useful tools to study auxin-type herbicides.
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Affiliation(s)
- Yuming Hu
- Laboratory of Functional Plant Biology, Department of Biology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat, Ghent, Belgium
| | - Thomas Depaepe
- Laboratory of Functional Plant Biology, Department of Biology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat, Ghent, Belgium
| | - Dajo Smet
- Laboratory of Functional Plant Biology, Department of Biology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat, Ghent, Belgium
| | - Klara Hoyerova
- Institute of Experimental Botany ASCR, Praha, Czech Republic
| | - Petr Klíma
- Institute of Experimental Botany ASCR, Praha, Czech Republic
| | - Ann Cuypers
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, Diepenbeek, Belgium
| | - Sean Cutler
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, USA
| | - Dieter Buyst
- NMR and Structure Analysis, Department of Organic Chemistry, Krijgslaan, Ghent, Belgium
| | - Kris Morreel
- Department of Plant Systems Biology, VIB (Flanders Institute for Biotechnology), Technologiepark, Ghent, Belgium
| | - Wout Boerjan
- Department of Plant Systems Biology, VIB (Flanders Institute for Biotechnology), Technologiepark, Ghent, Belgium
| | - José Martins
- NMR and Structure Analysis, Department of Organic Chemistry, Krijgslaan, Ghent, Belgium
| | - Jan Petrášek
- Institute of Experimental Botany ASCR, Praha, Czech Republic
| | - Filip Vandenbussche
- Laboratory of Functional Plant Biology, Department of Biology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat, Ghent, Belgium
| | - Dominique Van Der Straeten
- Laboratory of Functional Plant Biology, Department of Biology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat, Ghent, Belgium
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Miyakawa T, Tanokura M. Structural basis for the regulation of phytohormone receptors. Biosci Biotechnol Biochem 2017; 81:1261-1273. [PMID: 28417669 DOI: 10.1080/09168451.2017.1313696] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Phytohormones are central players in diverse plant physiological events, such as plant growth, development, and environmental stress and defense responses. The elucidation of their regulatory mechanisms through phytohormone receptors could facilitate the generation of transgenic crops with cultivation advantages and the rational design of growth control chemicals. During the last decade, accumulated structural data on phytohormone receptors have provided critical insights into the molecular mechanisms of phytohormone perception and signal transduction. Here, we review the structural bases of phytohormone recognition and receptor activation. As a common feature, phytohormones regulate the interaction between the receptors and their respective target proteins (also called co-receptors) by two types of regulatory mechanisms, acting as either "molecular glue" or an "allosteric regulator." However, individual phytohormone receptors adopt specific structural features that are essential for activation. In addition, recent studies have focused on the molecular diversity of redundant phytohormone receptors.
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Affiliation(s)
- Takuya Miyakawa
- a Department of Applied Biological Chemistry , Graduate School of Agricultural and Life Sciences, The University of Tokyo , Tokyo , Japan
| | - Masaru Tanokura
- a Department of Applied Biological Chemistry , Graduate School of Agricultural and Life Sciences, The University of Tokyo , Tokyo , Japan
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65
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Spartz AK, Lor VS, Ren H, Olszewski NE, Miller ND, Wu G, Spalding EP, Gray WM. Constitutive Expression of Arabidopsis SMALL AUXIN UP RNA19 (SAUR19) in Tomato Confers Auxin-Independent Hypocotyl Elongation. PLANT PHYSIOLOGY 2017; 173:1453-1462. [PMID: 27999086 PMCID: PMC5291034 DOI: 10.1104/pp.16.01514] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 12/18/2016] [Indexed: 05/18/2023]
Abstract
The plant hormone indole-3-acetic acid (IAA or auxin) mediates the elongation growth of shoot tissues by promoting cell expansion. According to the acid growth theory proposed in the 1970s, auxin activates plasma membrane H+-ATPases (PM H+-ATPases) to facilitate cell expansion by both loosening the cell wall through acidification and promoting solute uptake. Mechanistically, however, this process is poorly understood. Recent findings in Arabidopsis (Arabidopsis thaliana) have demonstrated that auxin-induced SMALL AUXIN UP RNA (SAUR) genes promote elongation growth and play a key role in PM H+-ATPase activation by inhibiting PP2C.D family protein phosphatases. Here, we extend these findings by demonstrating that SAUR proteins also inhibit tomato PP2C.D family phosphatases and that AtSAUR19 overexpression in tomato (Solanum lycopersicum) confers the same suite of phenotypes as previously reported for Arabidopsis. Furthermore, we employ a custom image-based method for measuring hypocotyl segment elongation with high resolution and a method for measuring cell wall mechanical properties, to add mechanistic details to the emerging description of auxin-mediated cell expansion. We find that constitutive expression of GFP-AtSAUR19 bypasses the normal requirement of auxin for elongation growth by increasing the mechanical extensibility of excised hypocotyl segments. In contrast, hypocotyl segments overexpressing a PP2C.D phosphatase are specifically impaired in auxin-mediated elongation. The time courses of auxin-induced SAUR expression and auxin-dependent elongation growth were closely correlated. These findings indicate that induction of SAUR expression is sufficient to elicit auxin-mediated expansion growth by activating PM H+-ATPases to facilitate apoplast acidification and mechanical wall loosening.
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Affiliation(s)
- Angela K Spartz
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108 (A.K.S., V.S.L., H.R., N.E.O., W.M.G.); and
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin 53706 (N.D.M., G.W., E.P.S.)
| | - Vai S Lor
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108 (A.K.S., V.S.L., H.R., N.E.O., W.M.G.); and
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin 53706 (N.D.M., G.W., E.P.S.)
| | - Hong Ren
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108 (A.K.S., V.S.L., H.R., N.E.O., W.M.G.); and
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin 53706 (N.D.M., G.W., E.P.S.)
| | - Neil E Olszewski
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108 (A.K.S., V.S.L., H.R., N.E.O., W.M.G.); and
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin 53706 (N.D.M., G.W., E.P.S.)
| | - Nathan D Miller
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108 (A.K.S., V.S.L., H.R., N.E.O., W.M.G.); and
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin 53706 (N.D.M., G.W., E.P.S.)
| | - Guosheng Wu
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108 (A.K.S., V.S.L., H.R., N.E.O., W.M.G.); and
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin 53706 (N.D.M., G.W., E.P.S.)
| | - Edgar P Spalding
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108 (A.K.S., V.S.L., H.R., N.E.O., W.M.G.); and
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin 53706 (N.D.M., G.W., E.P.S.)
| | - William M Gray
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108 (A.K.S., V.S.L., H.R., N.E.O., W.M.G.); and
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin 53706 (N.D.M., G.W., E.P.S.)
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66
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Fendrych M, Leung J, Friml J. TIR1/AFB-Aux/IAA auxin perception mediates rapid cell wall acidification and growth of Arabidopsis hypocotyls. eLife 2016; 5. [PMID: 27627746 PMCID: PMC5045290 DOI: 10.7554/elife.19048] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 09/13/2016] [Indexed: 12/28/2022] Open
Abstract
Despite being composed of immobile cells, plants reorient along directional stimuli. The hormone auxin is redistributed in stimulated organs leading to differential growth and bending. Auxin application triggers rapid cell wall acidification and elongation of aerial organs of plants, but the molecular players mediating these effects are still controversial. Here we use genetically-encoded pH and auxin signaling sensors, pharmacological and genetic manipulations available for Arabidopsis etiolated hypocotyls to clarify how auxin is perceived and the downstream growth executed. We show that auxin-induced acidification occurs by local activation of H+-ATPases, which in the context of gravity response is restricted to the lower organ side. This auxin-stimulated acidification and growth require TIR1/AFB-Aux/IAA nuclear auxin perception. In addition, auxin-induced gene transcription and specifically SAUR proteins are crucial downstream mediators of this growth. Our study provides strong experimental support for the acid growth theory and clarified the contribution of the upstream auxin perception mechanisms. DOI:http://dx.doi.org/10.7554/eLife.19048.001
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Affiliation(s)
- Matyáš Fendrych
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Jeffrey Leung
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, INRA - Centre de Versailles-Grignon, Saclay Plant Science, Versailles, France
| | - Jiří Friml
- Institute of Science and Technology Austria, Klosterneuburg, Austria
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67
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Fendrych M, Leung J, Friml J. TIR1/AFB-Aux/IAA auxin perception mediates rapid cell wall acidification and growth of Arabidopsis hypocotyls. eLife 2016; 5:e19048. [PMID: 27627746 DOI: 10.7554/elife.19048.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 09/13/2016] [Indexed: 05/24/2023] Open
Abstract
Despite being composed of immobile cells, plants reorient along directional stimuli. The hormone auxin is redistributed in stimulated organs leading to differential growth and bending. Auxin application triggers rapid cell wall acidification and elongation of aerial organs of plants, but the molecular players mediating these effects are still controversial. Here we use genetically-encoded pH and auxin signaling sensors, pharmacological and genetic manipulations available for Arabidopsis etiolated hypocotyls to clarify how auxin is perceived and the downstream growth executed. We show that auxin-induced acidification occurs by local activation of H+-ATPases, which in the context of gravity response is restricted to the lower organ side. This auxin-stimulated acidification and growth require TIR1/AFB-Aux/IAA nuclear auxin perception. In addition, auxin-induced gene transcription and specifically SAUR proteins are crucial downstream mediators of this growth. Our study provides strong experimental support for the acid growth theory and clarified the contribution of the upstream auxin perception mechanisms.
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Affiliation(s)
- Matyáš Fendrych
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Jeffrey Leung
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, INRA - Centre de Versailles-Grignon, Saclay Plant Science, Versailles, France
| | - Jiří Friml
- Institute of Science and Technology Austria, Klosterneuburg, Austria
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