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Koyama T, Zaizen H, Takahashi I, Nakamura H, Nakajima M, Asami T. Small Molecules with Thiourea Skeleton Induce Ethylene Response in Arabidopsis. Int J Mol Sci 2023; 24:12420. [PMID: 37569795 PMCID: PMC10418922 DOI: 10.3390/ijms241512420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/01/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023] Open
Abstract
Ethylene is the only gaseous plant hormone that regulates several aspects of plant growth, from seedling morphogenesis to fruit ripening and organ senescence. Ethylene also stimulates the germination of Striga hermonthica, a root parasitic weed that severely damages crops in sub-Saharan Africa. Thus, ethylene response stimulants can be used as weed and crop control agents. Ethylene and ethephon, an ethylene-releasing compound, are currently used as ethylene response inducers. However, since ethylene is a gas, which limits its practical application, we targeted the development of a solid ethylene response inducer that could overcome this disadvantage. We performed chemical screening using Arabidopsis thaliana "triple response" as an indicator of ethylene response. After screening, we selected a compound with a thiourea skeleton and named it ZKT1. We then synthesized various derivatives of ZKT1 and evaluated their ethylene-like activities in Arabidopsis. Some derivatives showed considerably higher activity than ZKT1, and their activity was comparable to that of 1-aminocyclopropane-1-carboxylate. Mode of action analysis using chemical inhibitors and ethylene signaling mutants revealed that ZKT1 derivatives activate the ethylene signaling pathway through interactions with its upstream components. These thiourea derivatives can potentially be potent crop-controlling chemicals.
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Affiliation(s)
| | | | | | | | | | - Tadao Asami
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan; (T.K.); (I.T.); (H.N.); (M.N.)
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2
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Huang J, Zhao X, Bürger M, Chory J, Wang X. The role of ethylene in plant temperature stress response. TRENDS IN PLANT SCIENCE 2023; 28:808-824. [PMID: 37055243 DOI: 10.1016/j.tplants.2023.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 02/15/2023] [Accepted: 03/07/2023] [Indexed: 06/17/2023]
Abstract
Temperature influences the seasonal growth and geographical distribution of plants. Heat or cold stress occur when temperatures exceed or fall below the physiological optimum ranges, resulting in detrimental and irreversible damage to plant growth, development, and yield. Ethylene is a gaseous phytohormone with an important role in plant development and multiple stress responses. Recent studies have shown that, in many plant species, both heat and cold stress affect ethylene biosynthesis and signaling pathways. In this review, we summarize recent advances in understanding the role of ethylene in plant temperature stress responses and its crosstalk with other phytohormones. We also discuss potential strategies and knowledge gaps that need to be adopted and filled to develop temperature stress-tolerant crops by optimizing ethylene response.
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Affiliation(s)
- Jianyan Huang
- National Center for Tea Plant Improvement, Key Laboratory of Biology, Genetics and Breeding of Special Economic Animals and Plants, Ministry of Agriculture and Rural Affairs, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China.
| | - Xiaobo Zhao
- Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Rural Affairs and Zhejiang Province, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Marco Bürger
- Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Joanne Chory
- Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Xinchao Wang
- National Center for Tea Plant Improvement, Key Laboratory of Biology, Genetics and Breeding of Special Economic Animals and Plants, Ministry of Agriculture and Rural Affairs, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China.
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Singh D, Gupta P, Singla-Pareek SL, Siddique KHM, Pareek A. The Journey from Two-Step to Multi-Step Phosphorelay Signaling Systems. Curr Genomics 2021; 22:59-74. [PMID: 34045924 PMCID: PMC8142344 DOI: 10.2174/1389202921666210105154808] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/21/2020] [Accepted: 12/18/2020] [Indexed: 11/22/2022] Open
Abstract
Background The two-component signaling (TCS) system is an important signal transduction machinery in prokaryotes and eukaryotes, excluding animals, that uses a protein phosphorylation mechanism for signal transmission. Conclusion Prokaryotes have a primitive type of TCS machinery, which mainly comprises a membrane-bound sensory histidine kinase (HK) and its cognate cytoplasmic response regulator (RR). Hence, it is sometimes referred to as two-step phosphorelay (TSP). Eukaryotes have more sophisticated signaling machinery, with an extra component - a histidine-containing phosphotransfer (HPT) protein that shuttles between HK and RR to communicate signal baggage. As a result, the TSP has evolved from a two-step phosphorelay (His–Asp) in simple prokaryotes to a multi-step phosphorelay (MSP) cascade (His–Asp–His–Asp) in complex eukaryotic organisms, such as plants, to mediate the signaling network. This molecular evolution is also reflected in the form of considerable structural modifications in the domain architecture of the individual components of the TCS system. In this review, we present TCS system's evolutionary journey from the primitive TSP to advanced MSP type across the genera. This information will be highly useful in designing the future strategies of crop improvement based on the individual members of the TCS machinery.
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Affiliation(s)
- Deepti Singh
- 1Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India; 2Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India; 3The UWA Institute of Agriculture, The University of Western Australia, Perth WA 6001, Australia; 4National Agri-Food Biotechnology Institute, Punjab, Ajitgarh 140306, India
| | - Priyanka Gupta
- 1Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India; 2Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India; 3The UWA Institute of Agriculture, The University of Western Australia, Perth WA 6001, Australia; 4National Agri-Food Biotechnology Institute, Punjab, Ajitgarh 140306, India
| | - Sneh Lata Singla-Pareek
- 1Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India; 2Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India; 3The UWA Institute of Agriculture, The University of Western Australia, Perth WA 6001, Australia; 4National Agri-Food Biotechnology Institute, Punjab, Ajitgarh 140306, India
| | - Kadambot H M Siddique
- 1Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India; 2Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India; 3The UWA Institute of Agriculture, The University of Western Australia, Perth WA 6001, Australia; 4National Agri-Food Biotechnology Institute, Punjab, Ajitgarh 140306, India
| | - Ashwani Pareek
- 1Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India; 2Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India; 3The UWA Institute of Agriculture, The University of Western Australia, Perth WA 6001, Australia; 4National Agri-Food Biotechnology Institute, Punjab, Ajitgarh 140306, India
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Zhao H, Yin CC, Ma B, Chen SY, Zhang JS. Ethylene signaling in rice and Arabidopsis: New regulators and mechanisms. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2021; 63:102-125. [PMID: 33095478 DOI: 10.1111/jipb.13028] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/21/2020] [Indexed: 05/22/2023]
Abstract
Ethylene is a gaseous hormone which plays important roles in both plant growth and development and stress responses. Based on studies in the dicot model plant species Arabidopsis, a linear ethylene signaling pathway has been established, according to which ethylene is perceived by ethylene receptors and transduced through CONSTITUTIVE TRIPLE RESPONSE 1 (CTR1) and ETHYLENE-INSENSITIVE 2 (EIN2) to activate transcriptional reprogramming. In addition to this canonical signaling pathway, an alternative ethylene receptor-mediated phosphor-relay pathway has also been proposed to participate in ethylene signaling. In contrast to Arabidopsis, rice, a monocot, grows in semiaquatic environments and has a distinct plant structure. Several novel regulators and/or mechanisms of the rice ethylene signaling pathway have recently been identified, indicating that the ethylene signaling pathway in rice has its own unique features. In this review, we summarize the latest progress and compare the conserved and divergent aspects of the ethylene signaling pathway between Arabidopsis and rice. The crosstalk between ethylene and other plant hormones is also reviewed. Finally, we discuss how ethylene regulates plant growth, stress responses and agronomic traits. These analyses should help expand our knowledge of the ethylene signaling mechanism and could further be applied for agricultural purposes.
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Affiliation(s)
- He Zhao
- State Key Lab of Plant Genomics, Institute of Genetics & Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Cui-Cui Yin
- State Key Lab of Plant Genomics, Institute of Genetics & Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Biao Ma
- Biology and Agriculture Research Center, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100024, China
| | - Shou-Yi Chen
- State Key Lab of Plant Genomics, Institute of Genetics & Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jin-Song Zhang
- State Key Lab of Plant Genomics, Institute of Genetics & Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
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Skalak J, Nicolas KL, Vankova R, Hejatko J. Signal Integration in Plant Abiotic Stress Responses via Multistep Phosphorelay Signaling. FRONTIERS IN PLANT SCIENCE 2021; 12:644823. [PMID: 33679861 PMCID: PMC7925916 DOI: 10.3389/fpls.2021.644823] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 01/26/2021] [Indexed: 05/02/2023]
Abstract
Plants growing in any particular geographical location are exposed to variable and diverse environmental conditions throughout their lifespan. The multifactorial environmental pressure resulted into evolution of plant adaptation and survival strategies requiring ability to integrate multiple signals that combine to yield specific responses. These adaptive responses enable plants to maintain their growth and development while acquiring tolerance to a variety of environmental conditions. An essential signaling cascade that incorporates a wide range of exogenous as well as endogenous stimuli is multistep phosphorelay (MSP). MSP mediates the signaling of essential plant hormones that balance growth, development, and environmental adaptation. Nevertheless, the mechanisms by which specific signals are recognized by a commonly-occurring pathway are not yet clearly understood. Here we summarize our knowledge on the latest model of multistep phosphorelay signaling in plants and the molecular mechanisms underlying the integration of multiple inputs including both hormonal (cytokinins, ethylene and abscisic acid) and environmental (light and temperature) signals into a common pathway. We provide an overview of abiotic stress responses mediated via MSP signaling that are both hormone-dependent and independent. We highlight the mutual interactions of key players such as sensor kinases of various substrate specificities including their downstream targets. These constitute a tightly interconnected signaling network, enabling timely adaptation by the plant to an ever-changing environment. Finally, we propose possible future directions in stress-oriented research on MSP signaling and highlight its potential importance for targeted crop breeding.
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Affiliation(s)
- Jan Skalak
- CEITEC - Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno, Czechia
| | - Katrina Leslie Nicolas
- CEITEC - Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno, Czechia
| | - Radomira Vankova
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
| | - Jan Hejatko
- CEITEC - Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno, Czechia
- *Correspondence: Jan Hejatko,
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Abstract
Ethylene is a gaseous phytohormone and the first of this hormone class to be discovered. It is the simplest olefin gas and is biosynthesized by plants to regulate plant development, growth, and stress responses via a well-studied signaling pathway. One of the earliest reported responses to ethylene is the triple response. This response is common in eudicot seedlings grown in the dark and is characterized by reduced growth of the root and hypocotyl, an exaggerated apical hook, and a thickening of the hypocotyl. This proved a useful assay for genetic screens and enabled the identification of many components of the ethylene-signaling pathway. These components include a family of ethylene receptors in the membrane of the endoplasmic reticulum (ER); a protein kinase, called constitutive triple response 1 (CTR1); an ER-localized transmembrane protein of unknown biochemical activity, called ethylene-insensitive 2 (EIN2); and transcription factors such as EIN3, EIN3-like (EIL), and ethylene response factors (ERFs). These studies led to a linear model, according to which in the absence of ethylene, its cognate receptors signal to CTR1, which inhibits EIN2 and prevents downstream signaling. Ethylene acts as an inverse agonist by inhibiting its receptors, resulting in lower CTR1 activity, which releases EIN2 inhibition. EIN2 alters transcription and translation, leading to most ethylene responses. Although this canonical pathway is the predominant signaling cascade, alternative pathways also affect ethylene responses. This review summarizes our current understanding of ethylene signaling, including these alternative pathways, and discusses how ethylene signaling has been manipulated for agricultural and horticultural applications.
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Affiliation(s)
- Brad M Binder
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
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Hofmann A, Müller S, Drechsler T, Berleth M, Caesar K, Rohr L, Harter K, Groth G. High-Level Expression, Purification and Initial Characterization of Recombinant Arabidopsis Histidine Kinase AHK1. PLANTS 2020; 9:plants9030304. [PMID: 32121559 PMCID: PMC7154865 DOI: 10.3390/plants9030304] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/18/2020] [Accepted: 02/24/2020] [Indexed: 01/16/2023]
Abstract
Plants employ a number of phosphorylation cascades in response to a wide range of environmental stimuli. Previous studies in Arabidopsis and yeast indicate that histidine kinase AHK1 is a positive regulator of drought and osmotic stress responses. Based on these studies AHK1 was proposed a plant osmosensor, although the molecular basis of plant osmosensing still remains unknown. To understand the molecular role and signaling mechanism of AHK1 in osmotic stress, we have expressed and purified full-length AHK1 from Arabidopsis in a bacterial host to allow for studies on the isolated transmembrane receptor. Purification of the recombinant protein solubilized from the host membranes was achieved in a single step by metal-affinity chromatography. Analysis of the purified AHK1 by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting show a single band indicating that the preparation is highly pure and devoid of contaminants or degradation products. In addition, gel filtration experiments indicate that the preparation is homogenous and monodisperse. Finally, CD-spectroscopy, phosphorylation activity, dimerization studies, and protein–protein interaction with plant phosphorylation targeting AHP2 demonstrate that the purified protein is functionally folded and acts as phospho-His or phospho-Asp phosphatase. Hence, the expression and purification of recombinant AHK1 reported here provide a basis for further detailed functional and structural studies of the receptor, which might help to understand plant osmosensing and osmosignaling on the molecular level.
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Affiliation(s)
- Alexander Hofmann
- Institute of Biochemical Plant Physiology, Heinrich Heine University, Düsseldorf 40225, Germany; (A.H.); (S.M.); (M.B.)
| | - Sophia Müller
- Institute of Biochemical Plant Physiology, Heinrich Heine University, Düsseldorf 40225, Germany; (A.H.); (S.M.); (M.B.)
| | - Thomas Drechsler
- Center for Plant Molecular Biology (ZMBP), Eberhard Karls Universität Tübingen, Tübingen 72076, Germany; (T.D.); (K.C.); (L.R.); (K.H.)
| | - Mareike Berleth
- Institute of Biochemical Plant Physiology, Heinrich Heine University, Düsseldorf 40225, Germany; (A.H.); (S.M.); (M.B.)
| | - Katharina Caesar
- Center for Plant Molecular Biology (ZMBP), Eberhard Karls Universität Tübingen, Tübingen 72076, Germany; (T.D.); (K.C.); (L.R.); (K.H.)
| | - Leander Rohr
- Center for Plant Molecular Biology (ZMBP), Eberhard Karls Universität Tübingen, Tübingen 72076, Germany; (T.D.); (K.C.); (L.R.); (K.H.)
| | - Klaus Harter
- Center for Plant Molecular Biology (ZMBP), Eberhard Karls Universität Tübingen, Tübingen 72076, Germany; (T.D.); (K.C.); (L.R.); (K.H.)
| | - Georg Groth
- Institute of Biochemical Plant Physiology, Heinrich Heine University, Düsseldorf 40225, Germany; (A.H.); (S.M.); (M.B.)
- Correspondence: ; Tel.: +49-211-811-2822
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Tan S, Debellé F, Gamas P, Frugier F, Brault M. Diversification of cytokinin phosphotransfer signaling genes in Medicago truncatula and other legume genomes. BMC Genomics 2019; 20:373. [PMID: 31088345 PMCID: PMC6518804 DOI: 10.1186/s12864-019-5724-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 04/22/2019] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Legumes can establish on nitrogen-deprived soils a symbiotic interaction with Rhizobia bacteria, leading to the formation of nitrogen-fixing root nodules. Cytokinin phytohormones are critical for triggering root cortical cell divisions at the onset of nodule initiation. Cytokinin signaling is based on a Two-Component System (TCS) phosphorelay cascade, involving successively Cytokinin-binding Histidine Kinase receptors, phosphorelay proteins shuttling between the cytoplasm and the nucleus, and Type-B Response Regulator (RRB) transcription factors activating the expression of cytokinin primary response genes. Among those, Type-A Response Regulators (RRA) exert a negative feedback on the TCS signaling. To determine whether the legume plant nodulation capacity is linked to specific features of TCS proteins, a genome-wide identification was performed in six legume genomes (Cajanus cajan, pigeonpea; Cicer arietinum, chickpea; Glycine max, soybean; Phaseolus vulgaris, common bean; Lotus japonicus; Medicago truncatula). The diversity of legume TCS proteins was compared to the one found in two non-nodulating species, Arabidopsis thaliana and Vitis vinifera, which are references for functional analyses of TCS components and phylogenetic analyses, respectively. RESULTS A striking expansion of non-canonical RRBs was identified, notably leading to the emergence of proteins where the conserved phosphor-accepting aspartate residue is replaced by a glutamate or an asparagine. M. truncatula genome-wide expression datasets additionally revealed that only a limited subset of cytokinin-related TCS genes is highly expressed in different organs, namely MtCHK1/MtCRE1, MtHPT1, and MtRRB3, suggesting that this "core" module potentially acts in most plant organs including nodules. CONCLUSIONS Further functional analyses are required to determine the relevance of these numerous non-canonical TCS RRBs in symbiotic nodulation, as well as of canonical MtHPT1 and MtRRB3 core signaling elements.
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Affiliation(s)
- Sovanna Tan
- IPS2 (Institute of Plant Sciences Paris-Saclay), CNRS, Université Paris-Sud, Université Paris-Diderot, INRA, Université d’Evry, Université Paris-Saclay, Rue de Noetzlin, 91190 Gif-sur-Yvette, France
| | - Frédéric Debellé
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Pascal Gamas
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Florian Frugier
- IPS2 (Institute of Plant Sciences Paris-Saclay), CNRS, Université Paris-Sud, Université Paris-Diderot, INRA, Université d’Evry, Université Paris-Saclay, Rue de Noetzlin, 91190 Gif-sur-Yvette, France
| | - Mathias Brault
- IPS2 (Institute of Plant Sciences Paris-Saclay), CNRS, Université Paris-Sud, Université Paris-Diderot, INRA, Université d’Evry, Université Paris-Saclay, Rue de Noetzlin, 91190 Gif-sur-Yvette, France
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Piya S, Binder BM, Hewezi T. Canonical and noncanonical ethylene signaling pathways that regulate Arabidopsis susceptibility to the cyst nematode Heterodera schachtii. THE NEW PHYTOLOGIST 2019; 221:946-959. [PMID: 30136723 DOI: 10.1111/nph.15400] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 07/13/2018] [Indexed: 05/29/2023]
Abstract
Plant-parasitic cyst nematodes successfully exploit various phytohormone signaling pathways to establish a new hormonal equilibrium that facilitates nematode parasitism. Although it is largely accepted that ethylene regulates plant responses to nematode infection, a mechanistic understanding of how ethylene shapes plant-nematode interactions remains largely unknown. In this study, we examined the involvement of various components regulating ethylene perception and signaling in establishing Arabidopsis susceptibility to the cyst nematode Heterodera schachtii using a large set of well-characterized single and higher order mutants. Our analyses revealed the existence of two pathways that separately engage ethylene with salicylic acid (SA) and cytokinin signaling during plant response to nematode infection. One pathway involves the canonical ethylene signaling pathway in which activation of ethylene signaling results in suppression of SA-based immunity. The second pathway involves the ethylene receptor ETR1, which signals independently of SA acid to affect immunity, instead altering cytokinin-mediated regulation of downstream components. Our results reveal important mechanisms through which cyst nematodes exploit components of ethylene perception and signaling to affect the balance of hormonal signaling through ethylene interaction with SA and cytokinin networks. This hormonal interaction overcomes plant defense and provokes a susceptible response.
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Affiliation(s)
- Sarbottam Piya
- Department of Plant Sciences, University of Tennessee, Knoxville, TN, 37996, USA
| | - Brad M Binder
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Tarek Hewezi
- Department of Plant Sciences, University of Tennessee, Knoxville, TN, 37996, USA
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Binder BM, Kim HJ, Mathews DE, Hutchison CE, Kieber JJ, Schaller GE. A role for two-component signaling elements in the Arabidopsis growth recovery response to ethylene. PLANT DIRECT 2018; 2:e00058. [PMID: 31245724 PMCID: PMC6508545 DOI: 10.1002/pld3.58] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 05/29/2023]
Abstract
Previous studies indicate that the ability of Arabidopsis seedlings to recover normal growth following an ethylene treatment involves histidine kinase activity of the ethylene receptors. As histidine kinases can function as inputs for a two-component signaling system, we examined loss-of-function mutants involving two-component signaling elements. We find that mutants of phosphotransfer proteins and type-B response regulators exhibit a defect in their ethylene growth recovery response similar to that found with the loss-of-function ethylene receptor mutant etr1-7. The ability of two-component signaling elements to regulate the growth recovery response to ethylene functions independently from their well-characterized role in cytokinin signaling, based on the analysis of cytokinin receptor mutants as well as following chemical inhibition of cytokinin biosynthesis. Histidine kinase activity of the receptor ETR1 also facilitates growth recovery in the ethylene hypersensitive response, which is characterized by a transient decrease in growth rate when seedlings are treated continuously with a low dose of ethylene; however, this response was found to operate independently of the type-B response regulators. These results indicate that histidine kinase activity of the ethylene receptor ETR1 performs two independent functions: (a) regulating the growth recovery to ethylene through a two-component signaling system involving phosphotransfer proteins and type-B response regulators and (b) regulating the hypersensitive response to ethylene in a type-B response regulator independent manner.
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Affiliation(s)
- Brad M. Binder
- Department of Biochemistry and Cellular & Molecular BiologyUniversity of TennesseeKnoxvilleTennessee
| | - Hyo Jung Kim
- Department of Biological SciencesDartmouth CollegeHanoverNew Hampshire
- Center for Plant Aging ResearchInstitute for Basic Science (IBS)DaeguKorea
| | - Dennis E. Mathews
- Department of Molecular, Cellular, and Biomedical SciencesUniversity of New HampshireDurhamNew Hampshire
| | - Claire E. Hutchison
- Department of BiologyUniversity of North CarolinaChapel HillNorth Carolina
- Present address:
William Harvey Research InstituteQueen Mary University of LondonCharterhouse SquareLondonEC1M 6BQUK
| | - Joseph J. Kieber
- Department of BiologyUniversity of North CarolinaChapel HillNorth Carolina
| | - G. Eric Schaller
- Department of Biological SciencesDartmouth CollegeHanoverNew Hampshire
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Pan J, Wang G, Wen H, Du H, Lian H, He H, Pan J, Cai R. Differential Gene Expression Caused by the F and M Loci Provides Insight Into Ethylene-Mediated Female Flower Differentiation in Cucumber. FRONTIERS IN PLANT SCIENCE 2018; 9:1091. [PMID: 30154805 PMCID: PMC6102477 DOI: 10.3389/fpls.2018.01091] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/05/2018] [Indexed: 05/06/2023]
Abstract
In cucumber (Cucumis sativus L.), the differentiation and development of female flowers are important processes that directly affect the fruit yield and quality. Sex differentiation is mainly controlled by three ethylene synthase genes, F (CsACS1G), M (CsACS2), and A (CsACS11). Thus, ethylene plays a key role in the sex differentiation in cucumber. The "one-hormone hypothesis" posits that F and M regulate the ethylene levels and initiate female flower development in cucumber. Nonetheless, the precise molecular mechanism of this process remains elusive. To investigate the mechanism by which F and M regulate the sex phenotype, three cucumber near-isogenic lines, namely H34 (FFmmAA, hermaphroditic), G12 (FFMMAA, gynoecious), and M12 (ffMMAA, monoecious), with different F and M loci were generated. The transcriptomic analysis of the apical shoots revealed that the expression of the B-class floral homeotic genes, CsPI (Csa4G358770) and CsAP3 (Csa3G865440), was immensely suppressed in G12 (100% female flowers) but highly expressed in M12 (∼90% male flowers). In contrast, CAG2 (Csa1G467100), which is an AG-like C-class floral homeotic gene, was specifically highly expressed in G12. Thus, the initiation of female flowers is likely to be caused by the downregulation of B-class and upregulation of C-class genes by ethylene production in the floral primordium. Additionally, CsERF31, which was highly expressed in G12, showed temporal and spatial expression patterns similar to those of M and responded to the ethylene-related chemical treatments. The biochemical experiments further demonstrated that CsERF31 could directly bind the promoter of M and promote its expression. Thus, CsERF31 responded to the ethylene signal derived from F and mediated the positive feedback regulation of ethylene by activating M expression, which offers an extended "one-hormone hypothesis" of sex differentiation in cucumber.
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Affiliation(s)
| | | | | | | | | | | | | | - Run Cai
- *Correspondence: Junsong Pan, ; Run Cai,
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Light KM, Wisniewski JA, Vinyard WA, Kieber-Emmons MT. Perception of the plant hormone ethylene: known-knowns and known-unknowns. J Biol Inorg Chem 2016; 21:715-28. [DOI: 10.1007/s00775-016-1378-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 07/19/2016] [Indexed: 12/18/2022]
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13
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Bisson MMA, Groth G. Targeting Plant Ethylene Responses by Controlling Essential Protein-Protein Interactions in the Ethylene Pathway. MOLECULAR PLANT 2015; 8:1165-74. [PMID: 25843012 DOI: 10.1016/j.molp.2015.03.014] [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: 09/04/2014] [Revised: 03/09/2015] [Accepted: 03/30/2015] [Indexed: 05/13/2023]
Abstract
The gaseous plant hormone ethylene regulates many processes of high agronomic relevance throughout the life span of plants. A central element in ethylene signaling is the endoplasmic reticulum (ER)-localized membrane protein ethylene insensitive2 (EIN2). Recent studies indicate that in response to ethylene, the extra-membranous C-terminal end of EIN2 is proteolytically processed and translocated from the ER to the nucleus. Here, we report that the conserved nuclear localization signal (NLS) mediating nuclear import of the EIN2 C-terminus provides an important domain for complex formation with ethylene receptor ethylene response1 (ETR1). EIN2 lacking the NLS domain shows strongly reduced affinity for the receptor. Interaction of EIN2 and ETR1 is also blocked by a synthetic peptide of the NLS motif. The corresponding peptide substantially reduces ethylene responses in planta. Our results uncover a novel mechanism and type of inhibitor interfering with ethylene signal transduction and ethylene responses in plants. Disruption of essential protein-protein interactions in the ethylene signaling pathway as shown in our study for the EIN2-ETR1 complex has the potential to guide the development of innovative ethylene antagonists for modern agriculture and horticulture.
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Affiliation(s)
- Melanie M A Bisson
- Institute of Biochemical Plant Physiology, Heinrich-Heine University Düsseldorf, D-40204 Düsseldorf, Germany
| | - Georg Groth
- Institute of Biochemical Plant Physiology, Heinrich-Heine University Düsseldorf, D-40204 Düsseldorf, Germany.
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14
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Zdarska M, Dobisová T, Gelová Z, Pernisová M, Dabravolski S, Hejátko J. Illuminating light, cytokinin, and ethylene signalling crosstalk in plant development. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4913-31. [PMID: 26022257 DOI: 10.1093/jxb/erv261] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Integrating important environmental signals with intrinsic developmental programmes is a crucial adaptive requirement for plant growth, survival, and reproduction. Key environmental cues include changes in several light variables, while important intrinsic (and highly interactive) regulators of many developmental processes include the phytohormones cytokinins (CKs) and ethylene. Here, we discuss the latest discoveries regarding the molecular mechanisms mediating CK/ethylene crosstalk at diverse levels of biosynthetic and metabolic pathways and their complex interactions with light. Furthermore, we summarize evidence indicating that multiple hormonal and light signals are integrated in the multistep phosphorelay (MSP) pathway, a backbone signalling pathway in plants. Inter alia, there are strong overlaps in subcellular localizations and functional similarities in components of these pathways, including receptors and various downstream agents. We highlight recent research demonstrating the importance of CK/ethylene/light crosstalk in selected aspects of plant development, particularly seed germination and early seedling development. The findings clearly demonstrate the crucial integration of plant responses to phytohormones and adaptive responses to environmental cues. Finally, we tentatively identify key future challenges to refine our understanding of the molecular mechanisms mediating crosstalk between light and hormonal signals, and their integration during plant life cycles.
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Affiliation(s)
- Marketa Zdarska
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno 62500, Czech Republic
| | - Tereza Dobisová
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno 62500, Czech Republic
| | - Zuzana Gelová
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno 62500, Czech Republic
| | - Markéta Pernisová
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno 62500, Czech Republic
| | - Siarhei Dabravolski
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno 62500, Czech Republic
| | - Jan Hejátko
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno 62500, Czech Republic
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15
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Abstract
Ethylene is a hormone involved in numerous aspects of growth, development, and responses to biotic and abiotic stresses in plants. Ethylene is perceived through its binding to endoplasmic reticulum-localized receptors that function as negative regulators of ethylene signaling in the absence of the hormone. In Arabidopsis thaliana, five structurally and functionally different ethylene receptors are present. These differ in their primary sequence, in the domains present, and in the type of kinase activity exhibited, which may suggest functional differences among the receptors. Whereas ethylene receptors functionally overlap to suppress ethylene signaling, certain other responses are controlled by specific receptors. In this review, I examine the nature of these receptor differences, how the evolution of the ethylene receptor gene family may provide insight into their differences, and how expression of receptors or their accessory proteins may underlie receptor-specific responses.
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16
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Cao YR, Chen HW, Li ZG, Tao JJ, Ma B, Zhang WK, Chen SY, Zhang JS. Tobacco ankyrin protein NEIP2 interacts with ethylene receptor NTHK1 and regulates plant growth and stress responses. PLANT & CELL PHYSIOLOGY 2015; 56:803-18. [PMID: 25634961 DOI: 10.1093/pcp/pcv009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 01/18/2015] [Indexed: 12/16/2023]
Abstract
Ethylene is a gaseous hormone that regulates many processes involved in plant growth, development and stress responses. Previously, we found that the tobacco ethylene receptor NTHK1 (Nicotiana tabacum histidine kinase 1) promotes seedling growth and affects plant salt stress responses. In this study, NTHK1 ethylene receptor-interacting protein 2 (NEIP2) was identified and further characterized in relation to these processes. NEIP2 contains three ankyrin repeats that mediate an interaction with NTHK1 as demonstrated by yeast two-hybrid, glutathione S-transferase (GST) pull-down and co-immunoprecipitation assays. NTHK1 phosphorylates NEIP2 in vitro. Salt stress and ethylene treatment induce NEIP2 accumulation in the first few hours and then the NEIP2 can be phosphorylated in planta. The overexpression of NTHK1 enhances NEIP2 accumulation in the presence of ethylene and salt stress. NEIP2 overexpression promotes plant growth but reduces ethylene responses, which is consistent with the functions of NTHK1. Additionally, NEIP2 improves plant performance under salt and oxidative stress. These results suggest that ethylene-induced NEIP2 probably acts as a brake to reduce ethylene response but resumes growth through interaction with NTHK1. Manipulation of NEIP2 may be beneficial for crop improvement.
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Affiliation(s)
- Yang-Rong Cao
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China These authors contributed equally to this work. Present address: Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Hao-Wei Chen
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China These authors contributed equally to this work
| | - Zhi-Gang Li
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China These authors contributed equally to this work
| | - Jian-Jun Tao
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Biao Ma
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wan-Ke Zhang
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Shou-Yi Chen
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jin-Song Zhang
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
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17
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Zhang J, Yu J, Wen CK. An alternate route of ethylene receptor signaling. FRONTIERS IN PLANT SCIENCE 2014; 5:648. [PMID: 25477894 PMCID: PMC4238421 DOI: 10.3389/fpls.2014.00648] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 11/03/2014] [Indexed: 05/29/2023]
Abstract
The gaseous plant hormone ethylene is perceived by a family of ethylene receptors and mediates an array of ethylene responses. In the absence of ethylene, receptor signaling is conveyed via the C-terminal histidine kinase domain to the N-terminus of the CONSTITUTIVE TRIPLE RESPONSE1 (CTR1) protein kinase, which represses ethylene signaling mediated by ETHYLENE INSENSITIVE2 (EIN2) followed by EIN3. In the presence of ethylene, the receptors are inactivated when ethylene binds to their N-terminal domain, and consequently CTR1 is inactive, allowing EIN2 and EIN3 to activate ethylene signaling. Recent findings have shown that the ethylene receptor N-terminal portion can conditionally mediate the receptor signal output in mutants lacking CTR1, thus providing evidence of an alternative pathway from the ethylene receptors not involving CTR1. Here we highlight the evidence for receptor signaling to an alternative pathway and suggest that receptor signaling is coordinated via the N- and C-termini, as we address the biological significance of the negative regulation of ethylene signaling by the two pathways.
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Affiliation(s)
| | | | - Chi-Kuang Wen
- *Correspondence: Chi-Kuang Wen, National Key Laboratory of Plant Molecular Genetics and National Center for Plant Gene Research (Shanghai), Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China e-mail:
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18
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Wilson RL, Bakshi A, Binder BM. Loss of the ETR1 ethylene receptor reduces the inhibitory effect of far-red light and darkness on seed germination of Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2014; 5:433. [PMID: 25221561 PMCID: PMC4147998 DOI: 10.3389/fpls.2014.00433] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 08/13/2014] [Indexed: 05/18/2023]
Abstract
When exposed to far-red light followed by darkness, wild-type Arabidopsis thaliana seeds fail to germinate or germinate very poorly. We have previously shown that the ethylene receptor ETR1 (ETHYLENE RESPONSE1) inhibits and ETR2 stimulates seed germination of Arabidopsis during salt stress. This function of ETR1 requires the full-length receptor. These roles are independent of ethylene levels and sensitivity and are mainly mediated by a change in abscisic acid (ABA) sensitivity. In the current study we find that etr1-6 and etr1-7 loss-of-function mutant seeds germinate better than wild-type seeds after illumination with far-red light or when germinated in the dark indicating an inhibitory role for ETR1. Surprisingly, this function of ETR1 does not require the receiver domain. No differences between these mutants and wild-type are seen when germination proceeds after treatment with white, blue, green, or red light. Loss of any of the other four ethylene receptor isoforms has no measurable effect on germination after far-red light treatment. An analysis of the transcript abundance for genes encoding ABA and gibberellic acid (GA) metabolic enzymes indicates that etr1-6 mutants may produce more GA and less ABA than wild-type seeds after illumination with far-red light which correlates with the better germination of the mutants. Epistasis analysis suggests that ETR1 may genetically interact with the phytochromes (phy), PHYA and PHYB to control germination and growth. This study shows that of the five ethylene receptor isoforms in Arabidopsis, ETR1 has a unique role in modulating the effects of red and far-red light on plant growth and development.
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Affiliation(s)
| | | | - Brad M. Binder
- Department of Biochemistry, Cellular, and Molecular Biology, University of TennesseeKnoxville, TN, USA
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19
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Wilson RL, Kim H, Bakshi A, Binder BM. The Ethylene Receptors ETHYLENE RESPONSE1 and ETHYLENE RESPONSE2 Have Contrasting Roles in Seed Germination of Arabidopsis during Salt Stress. PLANT PHYSIOLOGY 2014; 165:1353-1366. [PMID: 24820022 PMCID: PMC4081342 DOI: 10.1104/pp.114.241695] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 05/12/2014] [Indexed: 05/18/2023]
Abstract
In Arabidopsis (Arabidopsis thaliana), ethylene responses are mediated by a family of five receptors that have both overlapping and nonoverlapping roles. In this study, we used loss-of-function mutants for each receptor isoform to determine the role of individual isoforms in seed germination under salt stress. From this analysis, we found subfunctionalization of the receptors in the control of seed germination during salt stress. Specifically, loss of ETHYLENE RESPONSE1 (ETR1) or ETHYLENE INSENSITIVE4 (EIN4) leads to accelerated germination, loss of ETR2 delays germination, and loss of either ETHYLENE RESPONSE SENSOR1 (ERS1) or ERS2 has no measurable effect on germination. Epistasis analysis indicates that ETR1 and EIN4 function additively with ETR2 to control this trait. Interestingly, regulation of germination by ETR1 requires the full-length receptor. The differences in germination between etr1 and etr2 loss-of-function mutants under salt stress could not be explained by differences in the production of or sensitivity to ethylene, gibberellin, or cytokinin. Instead, etr1 loss-of-function mutants have reduced sensitivity to abscisic acid (ABA) and germinate earlier than the wild type, whereas etr2 loss-of-function mutants have increased sensitivity to ABA and germinate slower than the wild type. Additionally, the differences in seed germination on salt between the two mutants and the wild type are eliminated by the ABA biosynthetic inhibitor norflurazon. These data suggest that ETR1 and ETR2 have roles independent of ethylene signaling that affect ABA signaling and result in altered germination during salt stress.
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Affiliation(s)
- Rebecca L Wilson
- Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Heejung Kim
- Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Arkadipta Bakshi
- Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Brad M Binder
- Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
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20
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How plants sense ethylene gas--the ethylene receptors. J Inorg Biochem 2014; 133:58-62. [PMID: 24485009 DOI: 10.1016/j.jinorgbio.2014.01.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/08/2014] [Accepted: 01/09/2014] [Indexed: 11/23/2022]
Abstract
Ethylene is a hormone that affects many processes important for plant growth, development, and responses to stresses. The first step in ethylene signal transduction is when ethylene binds to its receptors. Numerous studies have examined how these receptors function. In this review we summarize many of these studies and present our current understanding about how ethylene binds to the receptors. The biochemical output of the receptors is not known but current models predict that when ethylene binds to the receptors, the activity of the associated protein kinase, CTR1 (constitutive triple response1), is reduced. This results in downstream transcriptional changes leading to ethylene responses. We present a model where a copper cofactor is required and the binding of ethylene causes the receptor to pass through a transition state to become non-signaling leading to lower CTR1 activity.
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21
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Shakeel SN, Wang X, Binder BM, Schaller GE. Mechanisms of signal transduction by ethylene: overlapping and non-overlapping signalling roles in a receptor family. AOB PLANTS 2013; 5:plt010. [PMID: 23543258 PMCID: PMC3611092 DOI: 10.1093/aobpla/plt010] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Accepted: 02/05/2013] [Indexed: 05/17/2023]
Abstract
The plant hormone ethylene regulates growth and development as well as responses to biotic and abiotic stresses. Over the last few decades, key elements involved in ethylene signal transduction have been identified through genetic approaches, these elements defining a pathway that extends from initial ethylene perception at the endoplasmic reticulum to changes in transcriptional regulation within the nucleus. Here, we present our current understanding of ethylene signal transduction, focusing on recent developments that support a model with overlapping and non-overlapping roles for members of the ethylene receptor family. We consider the evidence supporting this model for sub-functionalization within the receptor family, and then discuss mechanisms by which such a sub-functionalization may occur. To this end, we consider the importance of receptor interactions in modulating their signal output and how such interactions vary in the receptor family. In addition, we consider evidence indicating that ethylene signal output by the receptors involves both phosphorylation-dependent and phosphorylation-independent mechanisms. We conclude with a current model for signalling by the ethylene receptors placed within the overall context of ethylene signal transduction.
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Affiliation(s)
- Samina N. Shakeel
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
- Department of Biochemistry, Quaid-i-azam University, Islamabad 45320, Pakistan
| | - Xiaomin Wang
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Brad M. Binder
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - G. Eric Schaller
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
- Corresponding author's e-mail address:
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22
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Kim J, Patterson SE, Binder BM. Reducing jasmonic acid levels causes ein2 mutants to become ethylene responsive. FEBS Lett 2012; 587:226-30. [PMID: 23219920 DOI: 10.1016/j.febslet.2012.11.030] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 11/26/2012] [Accepted: 11/27/2012] [Indexed: 11/28/2022]
Abstract
It has previously been shown that jasmonic acid affects the ethylene signaling pathway. EIN2 is a central component of ethylene signaling that is downstream of the receptors. EIN2 has previously been shown to be required for ethylene responses. We found that reducing jasmonic acid levels, either mutationally or chemically, caused ein2 ethylene-insensitive mutants to become ethylene responsive. This effect was not seen with the ethylene-insensitive etr1-1 mutants that affect receptor function. Based upon these results, we propose a model where jasmonic acid is inhibiting ethylene signal transduction down-stream of the ethylene receptors. This may involve an EIN2-independent pathway.
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Affiliation(s)
- Joonyup Kim
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37917, USA
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23
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Mira-Rodado V, Veerabagu M, Witthöft J, Teply J, Harter K, Desikan R. Identification of two-component system elements downstream of AHK5 in the stomatal closure response of Arabidopsis thaliana. PLANT SIGNALING & BEHAVIOR 2012; 7:1467-76. [PMID: 22951399 PMCID: PMC3548872 DOI: 10.4161/psb.21898] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
To optimize water use efficiency, plants regulate stomatal closure through a complex signaling process. Hydrogen peroxide (H₂O₂) is produced in response to several environmental stimuli, and has been identified as a key second messenger involved in the regulation of stomatal aperture. The Arabidopsis histidine kinase 5 (AHK5) has been shown to regulate stomatal closure in response to H₂O₂ and other stimuli that depend on H₂O₂. AHK5 is a member of the two-component system (TCS) in Arabidopsis. The plant TCS comprises three different protein types: the hybrid histidine kinases (HKs), the phosphotransfer proteins (HPs) and the response regulators (RRs). Here we determined TCS elements involved in H₂O₂- and ethylene-dependent stomatal closure downstream of AHK5. By yeast and in planta interaction assays and functional studies, AHP1, 2 and 5 as well as the response regulators ARR4 and ARR7 were identified acting downstream of AHK5 in the ethylene and H₂O₂ response pathways of guard cells. Furthermore, we demonstrate that aspartate phosphorylation of ARR4 is only required for the H₂O₂- but not for the ethylene-induced stomatal closure response. Our data suggest the presence of a complex TCS signaling network comprising of at least AHK5, several AHPs and response regulators, which modulate stomatal closure in response to H₂O₂ and ethylene.
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Affiliation(s)
- Virtudes Mira-Rodado
- Center for Plant Molecular Biology (ZMBP); Department of Plant Physiology; University of Tübingen; Tübingen, Germany
| | - Manikandan Veerabagu
- Center for Plant Molecular Biology (ZMBP); Department of Plant Physiology; University of Tübingen; Tübingen, Germany
| | - Janika Witthöft
- Center for Plant Molecular Biology (ZMBP); Department of Plant Physiology; University of Tübingen; Tübingen, Germany
| | - Julia Teply
- Center for Plant Molecular Biology (ZMBP); Department of Plant Physiology; University of Tübingen; Tübingen, Germany
| | - Klaus Harter
- Center for Plant Molecular Biology (ZMBP); Department of Plant Physiology; University of Tübingen; Tübingen, Germany
| | - Radhika Desikan
- Department of Life Sciences; Imperial College London, South Kensington; London; United Kingdom
- Correspondence to: Radhika Desikan,
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24
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Hall BP, Shakeel SN, Amir M, Haq NU, Qu X, Schaller GE. Histidine kinase activity of the ethylene receptor ETR1 facilitates the ethylene response in Arabidopsis. PLANT PHYSIOLOGY 2012; 159:682-95. [PMID: 22467798 PMCID: PMC3375934 DOI: 10.1104/pp.112.196790] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 03/29/2012] [Indexed: 05/18/2023]
Abstract
In Arabidopsis (Arabidopsis thaliana), ethylene is perceived by a receptor family consisting of five members. Subfamily 1 members ETHYLENE RESPONSE1 (ETR1) and ETHYLENE RESPONSE SENSOR1 (ERS1) have histidine kinase activity, unlike the subfamily 2 members ETR2, ERS2, and ETHYLENE INSENSITIVE4 (EIN4), which lack amino acid residues critical for this enzymatic activity. To resolve the role of histidine kinase activity in signaling by the receptors, we transformed an etr1-9;ers1-3 double mutant with wild-type and kinase-inactive versions of the receptor ETR1. Both wild-type and kinase-inactive ETR1 rescue the constitutive ethylene-response phenotype of etr1-9;ers1-3, restoring normal growth to the mutant in air. However, the lines carrying kinase-inactive ETR1 exhibit reduced sensitivity to ethylene based on several growth response assays. Microarray and real-time polymerase chain reaction analyses of gene expression support a role for histidine kinase activity in eliciting the ethylene response. In addition, protein levels of the Raf-like kinase CONSTITUTIVE TRIPLE RESPONSE1 (CTR1), which physically associates with the ethylene receptor ETR1, are less responsive to ethylene in lines containing kinase-inactive ETR1. These data indicate that the histidine kinase activity of ETR1 is not required for but plays a modulating role in the regulation of ethylene responses. Models for how enzymatic and nonenzymatic regulation may facilitate signaling from the ethylene receptors are discussed.
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25
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Morey KJ, Antunes MS, Barrow MJ, Solorzano FA, Havens KL, Smith JJ, Medford J. Crosstalk between endogenous and synthetic components--synthetic signaling meets endogenous components. Biotechnol J 2012; 7:846-55. [PMID: 22649041 DOI: 10.1002/biot.201100487] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/12/2012] [Accepted: 05/02/2012] [Indexed: 12/17/2022]
Abstract
Synthetic biology uses biological components to engineer new functionality in living organisms. We have used the tools of synthetic biology to engineer detector plants that can sense man-made chemicals, such as the explosive trinitrotoluene, and induce a response detectable by eye or instrumentation. A goal of this type of work is to make the designed system orthogonal, that is, able to function independently of systems in the host. In this review, the design and function of two partially synthetic signaling pathways for use in plants is discussed. We describe observed interactions (crosstalk) with endogenous signaling components. This crosstalk can be beneficial, allowing the creation of hybrid synthetic/endogenous signaling pathways, or detrimental, resulting in system noise and/or false positives. Current approaches in the field of synthetic biology applicable to the design of orthogonal signaling systems, including the design of synthetic components, partially synthetic systems that utilize crosstalk to signal through endogenous components, computational redesign of proteins, and the use of heterologous components, are discussed.
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Affiliation(s)
- Kevin J Morey
- Department of Biology, Colorado State University, Fort Collins, CO, USA
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26
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Cyanide is an adequate agonist of the plant hormone ethylene for studying signalling of sensor kinase ETR1 at the molecular level. Biochem J 2012; 444:261-7. [DOI: 10.1042/bj20111447] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The plant hormone ethylene is involved in many developmental processes and responses to environmental stresses in plants. Although the elements of the signalling cascade and the receptors operating the ethylene pathway have been identified, a detailed understanding of the molecular processes related to signal perception and transfer is still lacking. Analysis of these processes using purified proteins in physical, structural and functional studies is complicated by the gaseous character of the plant hormone. In the present study, we show that cyanide, a π-acceptor compound and structural analogue of ethylene, is a suitable substitute for the plant hormone for in vitro studies with purified proteins. Recombinant ethylene receptor protein ETR1 (ethylene-resistant 1) showed high level and selective binding of [14C]cyanide in the presence of copper, a known cofactor in ethylene binding. Replacement of Cys65 in the ethylene-binding domain by serine dramatically reduced binding of radiolabelled cyanide. In contrast with wild-type ETR1, autokinase activity of the receptor is not reduced in the ETR1-C65S mutant upon addition of cyanide. Additionally, protein–protein interaction with the ethylene signalling protein EIN2 (ethylene-insensitive 2) is considerably sustained by cyanide in wild-type ETR1, but is not affected in the mutant. Further evidence for the structural and functional equivalence of ethylene and cyanide is given by the fact that the ethylene-responsive antagonist silver, which is known to allow ligand binding but prevent intrinsic signal transduction, also allows specific binding of cyanide, but shows no effect on autokinase activity and ETR1–EIN2 interaction.
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27
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Shi X, Rashotte AM. Advances in upstream players of cytokinin phosphorelay: receptors and histidine phosphotransfer proteins. PLANT CELL REPORTS 2012; 31:789-99. [PMID: 22350315 DOI: 10.1007/s00299-012-1229-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 01/13/2012] [Accepted: 01/14/2012] [Indexed: 05/09/2023]
Abstract
Cytokinins are a class of plant hormones that have been linked to numerous growth and developmental aspects in plants. The cytokinin signal is perceived by sensor histidine kinase receptors and transmitted via histidine phosphotransfer proteins (HPts) to downstream response regulators. Since their discovery, cytokinin receptors have been a focus of interest for many researchers. Ongoing research on these transmembrane receptors has greatly broadened our knowledge in terms of cytokinin-receptor interaction, receptor specificity, receptor cellular localization, and receptor functions in cytokinin related growth and developmental processes. This review focuses on the recent advances on the cytokinin receptors and HPt proteins in Arabidopsis.
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Affiliation(s)
- Xiuling Shi
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
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28
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Ju C, Chang C. Advances in ethylene signalling: protein complexes at the endoplasmic reticulum membrane. AOB PLANTS 2012; 2012:pls031. [PMID: 23119138 PMCID: PMC3485614 DOI: 10.1093/aobpla/pls031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 09/25/2012] [Indexed: 05/21/2023]
Abstract
The gaseous plant hormone ethylene plays critical roles in plant responses to environmental and endogenous signals that modulate growth and development. Over the past 25 years, great progress has been made in elucidating the ethylene signalling pathway. Genetic studies in Arabidopsis thaliana have identified key components of the pathway, and subcellular localization studies have shown that most of these components, other than transcription factors and protein turnover machinery, are associated with or lie within the endoplasmic reticulum (ER) membrane. The ethylene receptors are found in high-molecular-mass protein complexes and interact with the CTR1 serine/threonine protein kinase and the genetically downstream EIN2 Nramp-like protein. To more fully understand the ethylene signalling pathway, recent research has focused on examining the molecular connections between these components and how they are regulated. Here, we review recent advances and remaining gaps in our understanding of the early steps in the ethylene signalling pathway taking place at the ER.
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Phosphorylation alters the interaction of the Arabidopsis phosphotransfer protein AHP1 with its sensor kinase ETR1. PLoS One 2011; 6:e24173. [PMID: 21912672 PMCID: PMC3166298 DOI: 10.1371/journal.pone.0024173] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 08/01/2011] [Indexed: 11/19/2022] Open
Abstract
The ethylene receptor ethylene response 1 (ETR1) and the Arabidopsis histidine-containing phosphotransfer protein 1 (AHP1) form a tight complex in vitro. According to our current model ETR1 and AHP1 together with a response regulator form a phosphorelay system controlling the gene expression response to the plant hormone ethylene, similar to the two-component signaling in bacteria. The model implies that ETR1 functions as a sensor kinase and is autophosphorylated in the absence of ethylene. The phosphoryl group is then transferred onto a histidine at the canonical phosphorylation site in AHP1. For phosphoryl group transfer both binding partners need to form a tight complex. After ethylene binding the receptor is switched to the non-phosphorylated state. This switch is accompanied by a conformational change that decreases the affinity to the phosphorylated AHP1. To test this model we used fluorescence polarization and examined how the phosphorylation status of the proteins affects formation of the suggested ETR1−AHP1 signaling complex. We have employed various mutants of ETR1 and AHP1 mimicking permanent phosphorylation or preventing phosphorylation, respectively. Our results show that phosphorylation plays an important role in complex formation as affinity is dramatically reduced when the signaling partners are either both in their non-phosphorylated form or both in their phosphorylated form. On the other hand, affinity is greatly enhanced when either protein is in the phosphorylated state and the corresponding partner in its non-phosphorylated form. Our results indicate that interaction of ETR1 and AHP1 requires that ETR1 is a dimer, as in its functional state as receptor in planta.
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Pekárová B, Klumpler T, Třísková O, Horák J, Jansen S, Dopitová R, Borkovcová P, Papoušková V, Nejedlá E, Sklenář V, Marek J, Zídek L, Hejátko J, Janda L. Structure and binding specificity of the receiver domain of sensor histidine kinase CKI1 from Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 67:827-839. [PMID: 21569135 DOI: 10.1111/j.1365-313x.2011.04637.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Multistep phosphorelay (MSP) signaling mediates responses to a variety of important stimuli in plants. In Arabidopsis MSP, the signal is transferred from sensor histidine kinase (HK) via histidine phosphotransfer proteins (AHP1-AHP5) to nuclear response regulators. In contrast to ancestral two-component signaling in bacteria, protein interactions in plant MSP are supposed to be rather nonspecific. Here, we show that the C-terminal receiver domain of HK CKI1 (CKI1(RD) ) is responsible for the recognition of CKI1 downstream signaling partners, and specifically interacts with AHP2, AHP3 and AHP5 with different affinities. We studied the effects of Mg²⁺, the co-factor necessary for signal transduction via MSP, and phosphorylation-mimicking BeF₃⁻ on CKI1(RD) in solution, and determined the crystal structure of free CKI1(RD) and CKI1(RD) in a complex with Mg²⁺. We found that the structure of CKI1(RD) shares similarities with the only known structure of plant HK, ETR1(RD) , with the main differences being in loop L3. Magnesium binding induces the rearrangement of some residues around the active site of CKI1(RD) , as was determined by both X-ray crystallography and NMR spectroscopy. Collectively, these results provide initial insights into the nature of molecular mechanisms determining the specificity of MSP signaling and MSP catalysis in plants.
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Affiliation(s)
- Blanka Pekárová
- Department of Functional Genomics and Proteomics, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic
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Dong CH, Jang M, Scharein B, Malach A, Rivarola M, Liesch J, Groth G, Hwang I, Chang C. Molecular association of the Arabidopsis ETR1 ethylene receptor and a regulator of ethylene signaling, RTE1. J Biol Chem 2010; 285:40706-13. [PMID: 20952388 PMCID: PMC3003370 DOI: 10.1074/jbc.m110.146605] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 10/11/2010] [Indexed: 11/06/2022] Open
Abstract
The plant hormone ethylene plays important roles in growth and development. Ethylene is perceived by a family of membrane-bound receptors that actively repress ethylene responses. When the receptors bind ethylene, their signaling is shut off, activating responses. REVERSION-TO-ETHYLENE SENSITIVITY (RTE1) encodes a novel membrane protein conserved in plants and metazoans. Genetic analyses in Arabidopsis thaliana suggest that RTE1 promotes the signaling state of the ethylene receptor ETR1 through the ETR1 N-terminal domain. RTE1 and ETR1 have been shown to co-localize to the endoplasmic reticulum (ER) and Golgi apparatus in Arabidopsis. Here, we demonstrate a physical association of RTE1 and ETR1 using in vivo and in vitro methods. Interaction of RTE1 and ETR1 was revealed in vivo by bimolecular fluorescence complementation (BiFC) in a tobacco cell transient assay and in stably transformed Arabidopsis. The association was also observed using a truncated version of ETR1 comprising the N terminus (amino acids 1-349). Interaction of RTE1 and ETR1 was confirmed by co-immunoprecipitation from Arabidopsis. The interaction occurs with high affinity (K(d), 117 nM) based on tryptophan fluorescence spectroscopy using purified recombinant RTE1 and a tryptophan-less version of purified recombinant ETR1. An amino acid substitution (C161Y) in RTE1 that is known to confer an ETR1 loss-of-function phenotype correspondingly gives a nearly 12-fold increase in the dissociation constant (K(d), 1.38 μM). These findings indicate that a high affinity association of RTE1 and ETR1 is important in the regulation of ETR1.
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Affiliation(s)
- Chun-Hai Dong
- From the Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742
| | - Mihue Jang
- the Division of Integrative Biosciences and Biotechnology and Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, 790-784 Korea, and
| | - Benjamin Scharein
- the Department of Plant Biochemistry, Heinrich-Heine Universität, 40225 Düsseldorf, Germany
| | - Anuschka Malach
- the Department of Plant Biochemistry, Heinrich-Heine Universität, 40225 Düsseldorf, Germany
| | - Maximo Rivarola
- From the Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742
| | - Jeff Liesch
- From the Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742
| | - Georg Groth
- the Department of Plant Biochemistry, Heinrich-Heine Universität, 40225 Düsseldorf, Germany
| | - Inhwan Hwang
- the Division of Integrative Biosciences and Biotechnology and Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, 790-784 Korea, and
| | - Caren Chang
- From the Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742
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Bisson MMA, Groth G. New insight in ethylene signaling: autokinase activity of ETR1 modulates the interaction of receptors and EIN2. MOLECULAR PLANT 2010; 3:882-9. [PMID: 20591837 DOI: 10.1093/mp/ssq036] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Ethylene insensitive 2 (EIN2), an integral membrane protein of the ER network, has been identified as the central regulator of the ethylene signaling pathway. Still, the mechanism by which the ethylene signal is transferred from the receptors to EIN2 has not been solved yet. Here, we show that protein phosphorylation is a key mechanism to control the interaction of EIN2 and the receptors. In vivo and in vitro fluorescence studies reveal that the kinase domain of the receptors is essential for the interaction. Cyanide, an ethylene agonist, which is known to reduce auto-phosphorylation of the ethylene receptor ethylene resistant 1 (ETR1) or a mutation in the kinase domain of ETR1 that prevents auto-phosphorylation (H353A), increases the affinity of the receptors for EIN2. On the other hand, mimicking permanent auto-phosphorylation of ETR1 as in the mutant H353E releases the EIN2-ETR1 interaction from the control by the plant hormone. Based on our data, we propose a novel model on the integration of EIN2 in the ethylene signaling cascade.
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Affiliation(s)
- Melanie M A Bisson
- Heinrich-Heine Universität Düsseldorf, Biochemie der Pflanzen, Universitätsstr. 1, 40225 Düsseldorf, Germany
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Bisson MMA, Bleckmann A, Allekotte S, Groth G. EIN2, the central regulator of ethylene signalling, is localized at the ER membrane where it interacts with the ethylene receptor ETR1. Biochem J 2009; 424:1-6. [PMID: 19769567 DOI: 10.1042/bj20091102] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Genetic studies have identified the membrane protein EIN2 (ethylene insensitive 2) as a central component of ethylene signalling in Arabidopsis. In addition, EIN2 might take part in multiple hormone signalling pathways and in response to pathogens as demonstrated by recent genetic and biochemical studies. Here we show, by an integrated approach using in vivo and in vitro fluorescence techniques, that EIN2 is localized at the ER (endoplasmic reticulum) membrane where it shows specific interaction with the ethylene receptor protein ETR1.
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Affiliation(s)
- Melanie M A Bisson
- Department of Plant Biochemistry, Heinrich-Heine University, 40225 Düsseldorf, Universitätsstrasse 1, Germany
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