1
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Chien YC, Yoon GM. Subcellular dynamics of ethylene signaling drive plant plasticity to growth and stress: Spatiotemporal control of ethylene signaling in Arabidopsis. Bioessays 2024; 46:e2400043. [PMID: 38571390 DOI: 10.1002/bies.202400043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/15/2024] [Accepted: 03/19/2024] [Indexed: 04/05/2024]
Abstract
Volatile compounds, such as nitric oxide and ethylene gas, play a vital role as signaling molecules in organisms. Ethylene is a plant hormone that regulates a wide range of plant growth, development, and responses to stress and is perceived by a family of ethylene receptors that localize in the endoplasmic reticulum. Constitutive Triple Response 1 (CTR1), a Raf-like protein kinase and a key negative regulator for ethylene responses, tethers to the ethylene receptors, but undergoes nuclear translocation upon activation of ethylene signaling. This ER-to-nucleus trafficking transforms CTR1 into a positive regulator for ethylene responses, significantly enhancing stress resilience to drought and salinity. The nuclear trafficking of CTR1 demonstrates that the spatiotemporal control of ethylene signaling is essential for stress adaptation. Understanding the mechanisms governing the spatiotemporal control of ethylene signaling elements is crucial for unraveling the system-level regulatory mechanisms that collectively fine-tune ethylene responses to optimize plant growth, development, and stress adaptation.
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Affiliation(s)
- Yuan-Chi Chien
- Department of Botany and Plant Pathology and Center for Plant Biology, Purdue University, West Lafayette, Indiana, USA
| | - Gyeong Mee Yoon
- Department of Botany and Plant Pathology and Center for Plant Biology, Purdue University, West Lafayette, Indiana, USA
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2
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Liu H, Liu N, Peng C, Huang J, Hua W, Fu Z, Liu J. Two-Component System Genes in Brassica napus: Identification, Analysis, and Expression Patterns in Response to Abiotic and Biotic Stresses. Int J Mol Sci 2023; 24:17308. [PMID: 38139141 PMCID: PMC10743665 DOI: 10.3390/ijms242417308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
The two-component system (TCS), consisting of histidine kinases (HKs), histidine phosphotransfer proteins (HPs) and response regulators (RRs) in eukaryotes, plays pivotal roles in regulating plant growth, development, and responses to environment stimuli. However, the TCS genes were poorly characterized in rapeseed, which is an important tetraploid crop in Brassicaceae. In this work, a total of 182 BnaTCS genes were identified, including 43 HKs, 16 HPs, and 123 RRs, which was more than that in other crops due to segmental duplications during the process of polyploidization. It was significantly different in genetic diversity between the three subfamilies, and some members showed substantial genetic differentiation among the three rapeseed ecotypes. Several hormone- and stress-responsive cis-elements were identified in the putative promoter regions of BnaTCS genes. Furthermore, the expression of BnaTCS genes under abiotic stresses, exogenous phytohormone, and biotic stresses was analyzed, and numerous candidate stress-responsive genes were screened out. Meanwhile, using a natural population with 505 B. napus accessions, we explored the genetic effects of BnaTCS genes on salt tolerance by association mapping analysis and detected some significant association SNPs/genes. The result will help to further understand the functions of TCS genes in the developmental and stress tolerance improvement in B. napus.
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Affiliation(s)
- Hongfang Liu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan 430062, China; (H.L.)
| | - Nian Liu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan 430062, China; (H.L.)
| | - Chen Peng
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan 430062, China; (H.L.)
| | - Jiaquan Huang
- School of Breeding and Multiplication, Sanya Institute of Breeding and Multiplication, Hainan University, Sanya 570208, China
| | - Wei Hua
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan 430062, China; (H.L.)
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Zhengwei Fu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan 430062, China; (H.L.)
| | - Jing Liu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan 430062, China; (H.L.)
- Hubei Hongshan Laboratory, Wuhan 430070, China
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Paull RE, Ksouri N, Kantar M, Zerpa‐Catanho D, Chen NJ, Uruu G, Yue J, Guo S, Zheng Y, Wai CMJ, Ming R. Differential gene expression during floral transition in pineapple. PLANT DIRECT 2023; 7:e541. [PMID: 38028646 PMCID: PMC10644199 DOI: 10.1002/pld3.541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 09/20/2023] [Accepted: 09/26/2023] [Indexed: 12/01/2023]
Abstract
Pineapple (Ananas comosus var. comosus) and ornamental bromeliads are commercially induced to flower by treatment with ethylene or its analogs. The apex is transformed from a vegetative to a floral meristem and shows morphological changes in 8 to 10 days, with flowers developing 8 to 10 weeks later. During eight sampling stages ranging from 6 h to 8 days after treatment, 7961 genes were found to exhibit differential expression (DE) after the application of ethylene. In the first 3 days after treatment, there was little change in ethylene synthesis or in the early stages of the ethylene response. Subsequently, three ethylene response transcription factors (ERTF) were up-regulated and the potential gene targets were predicted to be the positive flowering regulator CONSTANS-like 3 (CO), a WUSCHEL gene, two APETALA1/FRUITFULL (AP1/FUL) genes, an epidermal patterning gene, and a jasmonic acid synthesis gene. We confirm that pineapple has lost the flowering repressor FLOWERING LOCUS C. At the initial stages, the SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) was not significantly involved in this transition. Another WUSCHEL gene and a PHD homeobox transcription factor, though not apparent direct targets of ERTF, were up-regulated within a day of treatment, their predicted targets being the up-regulated CO, auxin response factors, SQUAMOSA, and histone H3 genes with suppression of abscisic acid response genes. The FLOWERING LOCUS T (FT), TERMINAL FLOWER (TFL), AGAMOUS-like APETELAR (AP2), and SEPETALA (SEP) increased rapidly within 2 to 3 days after ethylene treatment. Two FT genes were up-regulated at the apex and not at the leaf bases after treatment, suggesting that transport did not occur. These results indicated that the ethylene response in pineapple and possibly most bromeliads act directly to promote the vegetative to flower transition via APETALA1/FRUITFULL (AP1/FUL) and its interaction with SPL, FT, TFL, SEP, and AP2. A model based on AP2/ERTF DE and predicted DE target genes was developed to give focus to future research. The identified candidate genes are potential targets for genetic manipulation to determine their molecular role in flower transition.
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Affiliation(s)
- Robert E. Paull
- Tropical Plant & Soil SciencesUniversity of Hawaii at ManoaHonoluluHawaiiUSA
| | - Najla Ksouri
- Laboratory of Genomics, Genetics and Breeding of Fruits and Grapevine, Experimental Aula Dei‐CSICZaragozaSpain
| | - Michael Kantar
- Tropical Plant & Soil SciencesUniversity of Hawaii at ManoaHonoluluHawaiiUSA
| | | | - Nancy Jung Chen
- Tropical Plant & Soil SciencesUniversity of Hawaii at ManoaHonoluluHawaiiUSA
| | - Gail Uruu
- Tropical Plant & Soil SciencesUniversity of Hawaii at ManoaHonoluluHawaiiUSA
| | - Jingjing Yue
- Center for Genomics and BiotechnologyFujian Agriculture and Forestry UniversityFuzhouChina
| | - Shiyong Guo
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational MedicineKunming University of Science and TechnologyKunmingYunnanChina
| | - Yun Zheng
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational MedicineKunming University of Science and TechnologyKunmingYunnanChina
| | | | - Ray Ming
- Department of Plant BiologyUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
- Center for Genomics and BiotechnologyFujian Agriculture and Forestry UniversityFuzhouChina
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4
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Brenya E, Dutta E, Herron B, Walden LH, Roberts DM, Binder BM. Ethylene-mediated metabolic priming increases photosynthesis and metabolism to enhance plant growth and stress tolerance. PNAS NEXUS 2023; 2:pgad216. [PMID: 37469928 PMCID: PMC10353721 DOI: 10.1093/pnasnexus/pgad216] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 06/13/2023] [Accepted: 06/20/2023] [Indexed: 07/21/2023]
Abstract
Enhancing crop yields is a major challenge because of an increasing human population, climate change, and reduction in arable land. Here, we demonstrate that long-lasting growth enhancement and increased stress tolerance occur by pretreatment of dark grown Arabidopsis seedlings with ethylene before transitioning into light. Plants treated this way had longer primary roots, more and longer lateral roots, and larger aerial tissue and were more tolerant to high temperature, salt, and recovery from hypoxia stress. We attributed the increase in plant growth and stress tolerance to ethylene-induced photosynthetic-derived sugars because ethylene pretreatment caused a 23% increase in carbon assimilation and increased the levels of glucose (266%), sucrose/trehalose (446%), and starch (87%). Metabolomic and transcriptomic analyses several days posttreatment showed a significant increase in metabolic processes and gene transcripts implicated in cell division, photosynthesis, and carbohydrate metabolism. Because of this large effect on metabolism, we term this "ethylene-mediated metabolic priming." Reducing photosynthesis with inhibitors or mutants prevented the growth enhancement, but this was partially rescued by exogenous sucrose, implicating sugars in this growth phenomenon. Additionally, ethylene pretreatment increased the levels of CINV1 and CINV2 encoding invertases that hydrolyze sucrose, and cinv1;cinv2 mutants did not respond to ethylene pretreatment with increased growth indicating increased sucrose breakdown is critical for this trait. A model is proposed where ethylene-mediated metabolic priming causes long-term increases in photosynthesis and carbohydrate utilization to increase growth. These responses may be part of the natural development of seedlings as they navigate through the soil to emerge into light.
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Affiliation(s)
- Eric Brenya
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Esha Dutta
- Genome Science and Technology Program, University of Tennessee, Knoxville, TN 37996, USA
| | - Brittani Herron
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Lauren H Walden
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Daniel M Roberts
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
- Genome Science and Technology Program, University of Tennessee, Knoxville, TN 37996, USA
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Azhar BJ, Abbas S, Aman S, Yamburenko MV, Chen W, Müller L, Uzun B, Jewell DA, Dong J, Shakeel SN, Groth G, Binder BM, Grigoryan G, Schaller GE. Basis for high-affinity ethylene binding by the ethylene receptor ETR1 of Arabidopsis. Proc Natl Acad Sci U S A 2023; 120:e2215195120. [PMID: 37253004 PMCID: PMC10266040 DOI: 10.1073/pnas.2215195120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 04/14/2023] [Indexed: 06/01/2023] Open
Abstract
The gaseous hormone ethylene is perceived in plants by membrane-bound receptors, the best studied of these being ETR1 from Arabidopsis. Ethylene receptors can mediate a response to ethylene concentrations at less than one part per billion; however, the mechanistic basis for such high-affinity ligand binding has remained elusive. Here we identify an Asp residue within the ETR1 transmembrane domain that plays a critical role in ethylene binding. Site-directed mutation of the Asp to Asn results in a functional receptor that has a reduced affinity for ethylene, but still mediates ethylene responses in planta. The Asp residue is highly conserved among ethylene receptor-like proteins in plants and bacteria, but Asn variants exist, pointing to the physiological relevance of modulating ethylene-binding kinetics. Our results also support a bifunctional role for the Asp residue in forming a polar bridge to a conserved Lys residue in the receptor to mediate changes in signaling output. We propose a new structural model for the mechanism of ethylene binding and signal transduction, one with similarities to that found in a mammalian olfactory receptor.
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Affiliation(s)
- Beenish J. Azhar
- Department of Biological Sciences, Dartmouth College, Hanover, NH03755
- Department of Biochemistry, Quaid-i-azam University, Islamabad45320, Pakistan
| | - Safdar Abbas
- Department of Biological Sciences, Dartmouth College, Hanover, NH03755
- Department of Biochemistry, Quaid-i-azam University, Islamabad45320, Pakistan
| | - Sitwat Aman
- Department of Biological Sciences, Dartmouth College, Hanover, NH03755
| | | | - Wei Chen
- Department of Biological Sciences, Dartmouth College, Hanover, NH03755
| | - Lena Müller
- Institute of Biochemical Plant Physiology, Heinrich Heine University Düsseldorf,40225Düsseldorf, Germany
| | - Buket Uzun
- Institute of Biochemical Plant Physiology, Heinrich Heine University Düsseldorf,40225Düsseldorf, Germany
| | - David A. Jewell
- Department of Computer Science, Dartmouth College, Hanover, NH03755
| | - Jian Dong
- Department of Biological Sciences, Dartmouth College, Hanover, NH03755
| | - Samina N. Shakeel
- Department of Biological Sciences, Dartmouth College, Hanover, NH03755
- Department of Biochemistry, Quaid-i-azam University, Islamabad45320, Pakistan
| | - Georg Groth
- Institute of Biochemical Plant Physiology, Heinrich Heine University Düsseldorf,40225Düsseldorf, Germany
| | - Brad M. Binder
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN37996
| | - Gevorg Grigoryan
- Department of Biological Sciences, Dartmouth College, Hanover, NH03755
- Department of Computer Science, Dartmouth College, Hanover, NH03755
| | - G. Eric Schaller
- Department of Biological Sciences, Dartmouth College, Hanover, NH03755
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Park HL, Seo DH, Lee HY, Bakshi A, Park C, Chien YC, Kieber JJ, Binder BM, Yoon GM. Ethylene-triggered subcellular trafficking of CTR1 enhances the response to ethylene gas. Nat Commun 2023; 14:365. [PMID: 36690618 PMCID: PMC9870993 DOI: 10.1038/s41467-023-35975-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 01/11/2023] [Indexed: 01/24/2023] Open
Abstract
The phytohormone ethylene controls plant growth and stress responses. Ethylene-exposed dark-grown Arabidopsis seedlings exhibit dramatic growth reduction, yet the seedlings rapidly return to the basal growth rate when ethylene gas is removed. However, the underlying mechanism governing this acclimation of dark-grown seedlings to ethylene remains enigmatic. Here, we report that ethylene triggers the translocation of the Raf-like protein kinase CONSTITUTIVE TRIPLE RESPONSE1 (CTR1), a negative regulator of ethylene signaling, from the endoplasmic reticulum to the nucleus. Nuclear-localized CTR1 stabilizes the ETHYLENE-INSENSITIVE3 (EIN3) transcription factor by interacting with and inhibiting EIN3-BINDING F-box (EBF) proteins, thus enhancing the ethylene response and delaying growth recovery. Furthermore, Arabidopsis plants with enhanced nuclear-localized CTR1 exhibited improved tolerance to drought and salinity stress. These findings uncover a mechanism of the ethylene signaling pathway that links the spatiotemporal dynamics of cellular signaling components to physiological responses.
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Affiliation(s)
- Hye Lin Park
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
- Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
| | - Dong Hye Seo
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
- Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
- Department of Systems Biology, Yonsei University, Seoul, 03722, Korea
| | - Han Yong Lee
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
- Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
- Department of Biology, Chosun University, Gwangju, 61452, Korea
| | - Arkadipta Bakshi
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
- Department of Botany, UW-Madison, Madison, WI, USA
| | - Chanung Park
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
- Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
| | - Yuan-Chi Chien
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
- Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
| | - Joseph J Kieber
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Brad M Binder
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Gyeong Mee Yoon
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA.
- Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA.
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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: 82] [Impact Index Per Article: 27.3] [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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Genome-Wide Characterization and Expression of Two-Component System Genes in Cytokinin-Regulated Gall Formation in Zizania latifolia. PLANTS 2020; 9:plants9111409. [PMID: 33105697 PMCID: PMC7690396 DOI: 10.3390/plants9111409] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/17/2020] [Accepted: 10/20/2020] [Indexed: 11/16/2022]
Abstract
The thickening of Zizania latifolia shoots, referred to as gall formation, depends on infection with the fungal endophyte Ustilago esculenta. The swollen and juicy shoots are a popular vegetable in Asia. A key role for cytokinin action in this process was postulated. Here, trans-zeatin stimulated swelling in fungi-infected Z. latifolia. A two-component system (TCS) linked cytokinin binding to receptors with transcriptional regulation in the nucleus and played important roles in diverse biological processes. We characterized 69 TCS genes encoding for 25 histidine kinase/histidine-kinase-like (HK(L)) (21 HKs and 4 HKLs), 8 histidine phosphotransfer proteins (HP) (5 authentic and 3 pseudo), and 36 response regulators (RR; 14 type A, 14 type B, 2 type C, and 6 pseudo) in the genome of Z. latifolia. These TCS genes have a close phylogenetic relationship with their rice counterparts. Nineteen duplicated TCS gene pairs were found and the ratio of nonsynonymous to synonymous mutations indicated that a strong purifying selection acted on these duplicated genes, leading to few mutations during evolution. Finally, ZlCHK1, ZlRRA5, ZIRRA9, ZlRRA10, ZlPRR1, and ZlPHYA expression was associated with gall formation. Among them, ARR5, ARR9, and ZlPHYA are quickly induced by trans-zeatin, suggesting a role for cytokinin signaling in shoot swelling of Z. latifolia.
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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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Chen Y, Rofidal V, Hem S, Gil J, Nosarzewska J, Berger N, Demolombe V, Bouzayen M, Azhar BJ, Shakeel SN, Schaller GE, Binder BM, Santoni V, Chervin C. Targeted Proteomics Allows Quantification of Ethylene Receptors and Reveals SlETR3 Accumulation in Never-Ripe Tomatoes. FRONTIERS IN PLANT SCIENCE 2019; 10:1054. [PMID: 31555314 PMCID: PMC6727826 DOI: 10.3389/fpls.2019.01054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 07/29/2019] [Indexed: 05/04/2023]
Abstract
Ethylene regulates fruit ripening and several plant functions (germination, plant growth, plant-microbe interactions). Protein quantification of ethylene receptors (ETRs) is essential to study their functions, but is impaired by low resolution tools such as antibodies that are mostly nonspecific, or the lack of sensitivity of shotgun proteomic approaches. We developed a targeted proteomic method, to quantify low-abundance proteins such as ETRs, and coupled this to mRNAs analyses, in two tomato lines: Wild Type (WT) and Never-Ripe (NR) which is insensitive to ethylene because of a gain-of-function mutation in ETR3. We obtained mRNA and protein abundance profiles for each ETR over the fruit development period. Despite a limiting number of replicates, we propose Pearson correlations between mRNA and protein profiles as interesting indicators to discriminate the two genotypes: such correlations are mostly positive in the WT and are affected by the NR mutation. The influence of putative post-transcriptional and post-translational changes are discussed. In NR fruits, the observed accumulation of the mutated ETR3 protein between ripening stages (Mature Green and Breaker + 8 days) may be a cause of NR tomatoes to stay orange. The label-free quantitative proteomics analysis of membrane proteins, concomitant to Parallel Reaction Monitoring analysis, may be a resource to study changes over tomato fruit development. These results could lead to studies about ETR subfunctions and interconnections over fruit development. Variations of RNA-protein correlations may open new fields of research in ETR regulation. Finally, similar approaches may be developed to study ETRs in whole plant development and plant-microorganism interactions.
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Affiliation(s)
- Yi Chen
- GBF, Université de Toulouse, INRA, Toulouse, France
| | - Valérie Rofidal
- BPMP, CNRS, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France
| | - Sonia Hem
- BPMP, CNRS, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France
| | - Julie Gil
- GBF, Université de Toulouse, INRA, Toulouse, France
- BPMP, CNRS, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France
| | | | - Nathalie Berger
- BPMP, CNRS, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France
| | - Vincent Demolombe
- BPMP, CNRS, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France
| | | | - Beenish J. Azhar
- Department of Biochemistry, Quaid-i-azam University, Islamabad, Pakistan
- Department of Biological Sciences, Dartmouth College, Hanover, NH, United States
| | - Samina N. Shakeel
- Department of Biochemistry, Quaid-i-azam University, Islamabad, Pakistan
- Department of Biological Sciences, Dartmouth College, Hanover, NH, United States
| | - G. Eric Schaller
- Department of Biological Sciences, Dartmouth College, Hanover, NH, United States
| | - Brad M. Binder
- Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, TN, United States
| | - Véronique Santoni
- BPMP, CNRS, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France
- *Correspondence: Véronique Santoni, ; Christian Chervin,
| | - Christian Chervin
- GBF, Université de Toulouse, INRA, Toulouse, France
- *Correspondence: Véronique Santoni, ; Christian Chervin,
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Harkey AF, Yoon GM, Seo DH, DeLong A, Muday GK. Light Modulates Ethylene Synthesis, Signaling, and Downstream Transcriptional Networks to Control Plant Development. FRONTIERS IN PLANT SCIENCE 2019; 10:1094. [PMID: 31572414 PMCID: PMC6751313 DOI: 10.3389/fpls.2019.01094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 08/09/2019] [Indexed: 05/17/2023]
Abstract
The inhibition of hypocotyl elongation by ethylene in dark-grown seedlings was the basis of elegant screens that identified ethylene-insensitive Arabidopsis mutants, which remained tall even when treated with high concentrations of ethylene. This simple approach proved invaluable for identification and molecular characterization of major players in the ethylene signaling and response pathway, including receptors and downstream signaling proteins, as well as transcription factors that mediate the extensive transcriptional remodeling observed in response to elevated ethylene. However, the dark-adapted early developmental stage used in these experiments represents only a small segment of a plant's life cycle. After a seedling's emergence from the soil, light signaling pathways elicit a switch in developmental programming and the hormonal circuitry that controls it. Accordingly, ethylene levels and responses diverge under these different environmental conditions. In this review, we compare and contrast ethylene synthesis, perception, and response in light and dark contexts, including the molecular mechanisms linking light responses to ethylene biology. One powerful method to identify similarities and differences in these important regulatory processes is through comparison of transcriptomic datasets resulting from manipulation of ethylene levels or signaling under varying light conditions. We performed a meta-analysis of multiple transcriptomic datasets to uncover transcriptional responses to ethylene that are both light-dependent and light-independent. We identified a core set of 139 transcripts with robust and consistent responses to elevated ethylene across three root-specific datasets. This "gold standard" group of ethylene-regulated transcripts includes mRNAs encoding numerous proteins that function in ethylene signaling and synthesis, but also reveals a number of previously uncharacterized gene products that may contribute to ethylene response phenotypes. Understanding these light-dependent differences in ethylene signaling and synthesis will provide greater insight into the roles of ethylene in growth and development across the entire plant life cycle.
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Affiliation(s)
- Alexandria F. Harkey
- Department of Biology and Center for Molecular Signaling, Wake Forest University, Winston-Salem, NC, United States
| | - Gyeong Mee Yoon
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, United States
| | - Dong Hye Seo
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, United States
| | - Alison DeLong
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, United States
| | - Gloria K. Muday
- Department of Biology and Center for Molecular Signaling, Wake Forest University, Winston-Salem, NC, United States
- *Correspondence: Gloria K. Muday,
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12
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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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13
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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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14
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Harkey AF, Watkins JM, Olex AL, DiNapoli KT, Lewis DR, Fetrow JS, Binder BM, Muday GK. Identification of Transcriptional and Receptor Networks That Control Root Responses to Ethylene. PLANT PHYSIOLOGY 2018; 176:2095-2118. [PMID: 29259106 PMCID: PMC5841720 DOI: 10.1104/pp.17.00907] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 12/17/2017] [Indexed: 05/20/2023]
Abstract
Transcriptomic analyses with high temporal resolution provide substantial new insight into hormonal response networks. This study identified the kinetics of genome-wide transcript abundance changes in response to elevated levels of the plant hormone ethylene in roots from light-grown Arabidopsis (Arabidopsis thaliana) seedlings, which were overlaid on time-matched developmental changes. Functional annotation of clusters of transcripts with similar temporal patterns revealed rapidly induced clusters with known ethylene function and more slowly regulated clusters with novel predicted functions linked to root development. In contrast to studies with dark-grown seedlings, where the canonical ethylene response transcription factor, EIN3, is central to ethylene-mediated development, the roots of ein3 and eil1 single and double mutants still respond to ethylene in light-grown seedlings. Additionally, a subset of these clusters of ethylene-responsive transcripts were enriched in targets of EIN3 and ERFs. These results are consistent with EIN3-independent developmental and transcriptional changes in light-grown roots. Examination of single and multiple gain-of-function and loss-of-function receptor mutants revealed that, of the five ethylene receptors, ETR1 controls lateral root and root hair initiation and elongation and the synthesis of other receptors. These results provide new insight into the transcriptional and developmental responses to ethylene in light-grown seedlings.
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Affiliation(s)
- Alexandria F Harkey
- Department of Biology and Center for Molecular Signaling, Wake Forest University, Winston-Salem, North Carolina 27109
| | - Justin M Watkins
- Department of Biology and Center for Molecular Signaling, Wake Forest University, Winston-Salem, North Carolina 27109
| | - Amy L Olex
- Department of Computer Science, Wake Forest University, Winston-Salem, North Carolina 27109
| | - Kathleen T DiNapoli
- Department of Biology and Center for Molecular Signaling, Wake Forest University, Winston-Salem, North Carolina 27109
| | - Daniel R Lewis
- Department of Biology and Center for Molecular Signaling, Wake Forest University, Winston-Salem, North Carolina 27109
| | - Jacquelyn S Fetrow
- Department of Computer Science, Wake Forest University, Winston-Salem, North Carolina 27109
| | - Brad M Binder
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Gloria K Muday
- Department of Biology and Center for Molecular Signaling, Wake Forest University, Winston-Salem, North Carolina 27109
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15
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Milić D, Dick M, Mulnaes D, Pfleger C, Kinnen A, Gohlke H, Groth G. Recognition motif and mechanism of ripening inhibitory peptides in plant hormone receptor ETR1. Sci Rep 2018; 8:3890. [PMID: 29497085 PMCID: PMC5832771 DOI: 10.1038/s41598-018-21952-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 02/13/2018] [Indexed: 12/21/2022] Open
Abstract
Synthetic peptides derived from ethylene-insensitive protein 2 (EIN2), a central regulator of ethylene signalling, were recently shown to delay fruit ripening by interrupting protein-protein interactions in the ethylene signalling pathway. Here, we show that the inhibitory peptide NOP-1 binds to the GAF domain of ETR1 - the prototype of the plant ethylene receptor family. Site-directed mutagenesis and computational studies reveal the peptide interaction site and a plausible molecular mechanism for the ripening inhibition.
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Affiliation(s)
- Dalibor Milić
- Institute of Biochemical Plant Physiology and Bioeconomy Science Center (BioSC), Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Markus Dick
- Institute of Pharmaceutical and Medicinal Chemistry and Bioeconomy Science Center (BioSC), Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | - Daniel Mulnaes
- Institute of Pharmaceutical and Medicinal Chemistry and Bioeconomy Science Center (BioSC), Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Christopher Pfleger
- Institute of Pharmaceutical and Medicinal Chemistry and Bioeconomy Science Center (BioSC), Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Anna Kinnen
- Institute of Biochemical Plant Physiology and Bioeconomy Science Center (BioSC), Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Holger Gohlke
- Institute of Pharmaceutical and Medicinal Chemistry and Bioeconomy Science Center (BioSC), Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
- John von Neumann Institute for Computing (NIC), Jülich Supercomputing Centre (JSC) & Institute for Complex Systems - Structural Biochemistry (ICS 6), Forschungszentrum Jülich GmbH, Jülich, Germany.
| | - Georg Groth
- Institute of Biochemical Plant Physiology and Bioeconomy Science Center (BioSC), Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
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16
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Bakshi A, Piya S, Fernandez JC, Chervin C, Hewezi T, Binder BM. Ethylene Receptors Signal via a Noncanonical Pathway to Regulate Abscisic Acid Responses. PLANT PHYSIOLOGY 2018; 176:910-929. [PMID: 29158332 PMCID: PMC5761792 DOI: 10.1104/pp.17.01321] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 11/17/2017] [Indexed: 05/04/2023]
Abstract
Ethylene is a gaseous plant hormone perceived by a family of receptors in Arabidopsis (Arabidopsis thaliana) including ETHYLENE RESPONSE1 (ETR1) and ETR2. Previously we showed that etr1-6 loss-of-function plants germinate better and etr2-3 loss-of-function plants germinate worse than wild-type under NaCl stress and in response to abscisic acid (ABA). In this study, we expanded these results by showing that ETR1 and ETR2 have contrasting roles in the control of germination under a variety of inhibitory conditions for seed germination such as treatment with KCl, CuSO4, ZnSO4, and ethanol. Pharmacological and molecular biology results support a model where ETR1 and ETR2 are indirectly affecting the expression of genes encoding ABA signaling proteins to affect ABA sensitivity. The receiver domain of ETR1 is involved in this function in germination under these conditions and controlling the expression of genes encoding ABA signaling proteins. Epistasis analysis demonstrated that these contrasting roles of ETR1 and ETR2 do not require the canonical ethylene signaling pathway. To explore the importance of receptor-protein interactions, we conducted yeast two-hybrid screens using the cytosolic domains of ETR1 and ETR2 as bait. Unique interacting partners with either ETR1 or ETR2 were identified. We focused on three of these proteins and confirmed the interactions with receptors. Loss of these proteins led to faster germination in response to ABA, showing that they are involved in ABA responses. Thus, ETR1 and ETR2 have both ethylene-dependent and -independent roles in plant cells that affect responses to ABA.
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Affiliation(s)
- Arkadipta Bakshi
- Genome Science and Technology Program, University of Tennessee, Knoxville, Tennessee, 37996
| | - Sarbottam Piya
- Department of Plant Sciences, University of Tennessee, Knoxville, Tennessee, 37996
| | - Jessica C Fernandez
- Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, Tennessee, 37996
| | - Christian Chervin
- Université de Toulouse, INP-ENSAT, INRA, UMR 990 Génomique et Biotechnologie des Fruits, F-31326 Castanet-Tolosan Cedex, France
| | - Tarek Hewezi
- Genome Science and Technology Program, University of Tennessee, Knoxville, Tennessee, 37996
- Department of Plant Sciences, University of Tennessee, Knoxville, Tennessee, 37996
| | - Brad M Binder
- Genome Science and Technology Program, University of Tennessee, Knoxville, Tennessee, 37996
- Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, Tennessee, 37996
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17
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Analysis of Ethylene Receptors: Assay for Histidine Kinase Activity. Methods Mol Biol 2017. [PMID: 28293842 DOI: 10.1007/978-1-4939-6854-1_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The ethylene receptors of plants exist in two subfamilies. Members of subfamily-1 have functional histidine kinase domains, whereas members of subfamily-2 have diverged histidine-kinase-like domains that in some cases have been shown to exhibit Ser/Thr kinase activity. Here, we describe a method to biochemically characterize the enzymatic activity of these kinase domains in vitro. For this purpose, the histidine kinase domain of the receptors is transgenically expressed in yeast as a fusion to glutathione-S-transferase (GST) for subsequent affinity purification. Autophosphorylation activity is assessed by the use of an in vitro kinase assay with the purified protein. Acid/base stability of the incorporated phosphate can then be used as a diagnostic for whether His, Asp, or Ser/Thr/Tyr is phosphorylated.
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18
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Tucker ML, Kim J, Wen CK. Treatment of Plants with Gaseous Ethylene and Gaseous Inhibitors of Ethylene Action. Methods Mol Biol 2017; 1573:27-39. [PMID: 28293837 DOI: 10.1007/978-1-4939-6854-1_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The gaseous nature of ethylene affects not only its role in plant biology but also how you treat plants with the hormone. In many ways, it simplifies the treatment problem. Other hormones have to be made up in solution and applied to some part of the plant hoping the hormone will be taken up into the plant and translocated throughout the plant at the desired concentration. Because all plant cells are connected by an intercellular gas space the ethylene concentration you treat with is relatively quickly reached throughout the plant. In some instances, like mature fruit, treatment with ethylene initiates autocatalytic synthesis of ethylene. However, in most experiments, the exogenous ethylene concentration is saturating, usually >1 μL L-1, and the synthesis of additional ethylene is inconsequential. Also facilitating ethylene research compared with other hormones is that there are inhibitors of ethylene action 1-MCP (1-methylcyclopropene) and 2,5-NBD (2,5-norbornadiene) that are also gases wherein you can achieve nearly 100% inhibition of ethylene action quickly and with few side effects. Inhibitors for other plant hormones are applied as a solution and their transport and concentration at the desired site is not always known and difficult to measure. Here, our focus is on how to treat plants and plant parts with the ethylene gas and the gaseous inhibitors of ethylene action.
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Affiliation(s)
- Mark L Tucker
- Soybean Genomics and Improvement Lab, USDA/ARS, Bldg 006, BARC-West, 10300 Baltimore Ave, Beltsville, MD, 20705, USA.
| | - Joonyup Kim
- Department of Cell Biology and Molecular Genetics, Biosciences Research Bldg, University of Maryland, College Park, MD, 20742, USA
| | - Chi-Kuang Wen
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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19
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Binder BM. Time-Lapse Imaging to Examine the Growth Kinetics of Arabidopsis Seedlings in Response to Ethylene. Methods Mol Biol 2017; 1573:211-222. [PMID: 28293848 DOI: 10.1007/978-1-4939-6854-1_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Ethylene is well known to inhibit the growth of dark-grown eudicot seedlings. Most studies examine this inhibition after several days of exposure to ethylene. However, such end-point analysis misses transient responses and the dynamic nature of growth regulation. Here, high-resolution, time-lapse imaging is described as a method to gather data about ethylene growth kinetics and movement responses of the hypocotyls of dark-grown seedlings of Arabidopsis thaliana. These methods allow for the characterization of short-term kinetic responses and can be modified for the analysis of roots and seedlings from other species.
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Affiliation(s)
- Brad M Binder
- Department of Biochemistry & Cellular and Molecular Biology, M407 Walters Life Sciences, University of Tennessee, 1414 Cumberland Avenue, Knoxville, TN, 37996, USA.
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20
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Le Deunff E, Lecourt J, Malagoli P. Fine-tuning of root elongation by ethylene: a tool to study dynamic structure-function relationships between root architecture and nitrate absorption. ANNALS OF BOTANY 2016; 118:607-620. [PMID: 27411681 PMCID: PMC5055632 DOI: 10.1093/aob/mcw123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 02/26/2016] [Accepted: 05/12/2016] [Indexed: 05/08/2023]
Abstract
Background Recently developed genetic and pharmacological approaches have been used to explore NO3-/ethylene signalling interactions and how the modifications in root architecture by pharmacological modulation of ethylene biosynthesis affect nitrate uptake. Key Results Structure-function studies combined with recent approaches to chemical genomics highlight the non-specificity of commonly used inhibitors of ethylene biosynthesis such as AVG (l-aminoethoxyvinylglycine). Indeed, AVG inhibits aminotransferases such as ACC synthase (ACS) and tryptophan aminotransferase (TAA) involved in ethylene and auxin biosynthesis but also some aminotransferases implied in nitrogen (N) metabolism. In this framework, it can be assumed that the products of nitrate assimilation and hormones may interact through a hub in carbon (C) and N metabolism to drive the root morphogenetic programme (RMP). Although ethylene/auxin interactions play a major role in cell division and elongation in root meristems, shaping of the root system depends also on energetic considerations. Based on this finding, the analysis is extended to nutrient ion-hormone interactions assuming a fractal or constructal model for root development. Conclusion Therefore, the tight control of root structure-function in the RMP may explain why over-expressing nitrate transporter genes to decouple structure-function relationships and improve nitrogen use efficiency (NUE) has been unsuccessful.
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Affiliation(s)
- Erwan Le Deunff
- Université de Caen Basse-Normandie, UMR Écophysiologie Végétale & Agronomie, Nutritions NCS, F-14032 Caen, France
- INRA, UMR 950, Écophysiologie Végétale & Agronomie, Nutritions NCS, F-14032 Caen, France
| | - Julien Lecourt
- East Malling Research, New Road, East Malling ME19 6BJ, Kent, UK
| | - Philippe Malagoli
- Université Blaise Pascal-INRA, 24, avenue des Landais, BP 80 006, F-63177 Aubière, France
- INRA, UMR 547 PIAF, Bâtiment Biologie Végétale Recherche, BP 80 006, F-63177 Aubière, France
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21
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Hung YL, Jiang I, Lee YZ, Wen CK, Sue SC. NMR Study Reveals the Receiver Domain of Arabidopsis ETHYLENE RESPONSE1 Ethylene Receptor as an Atypical Type Response Regulator. PLoS One 2016; 11:e0160598. [PMID: 27486797 PMCID: PMC4972365 DOI: 10.1371/journal.pone.0160598] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 07/21/2016] [Indexed: 11/26/2022] Open
Abstract
The gaseous plant hormone ethylene, recognized by plant ethylene receptors, plays a pivotal role in various aspects of plant growth and development. ETHYLENE RESPONSE1 (ETR1) is an ethylene receptor isolated from Arabidopsis and has a structure characteristic of prokaryotic two-component histidine kinase (HK) and receiver domain (RD), where the RD structurally resembles bacteria response regulators (RRs). The ETR1 HK domain has autophosphorylation activity, and little is known if the HK can transfer the phosphoryl group to the RD for receptor signaling. Unveiling the correlation of the receptor structure and phosphorylation status would advance the studies towards the underlying mechanisms of ETR1 receptor signaling. In this study, using the nuclear magnetic resonance technique, our data suggested that the ETR1-RD is monomeric in solution and the rigid structure of the RD prevents the conserved aspartate residue phosphorylation. Comparing the backbone dynamics with other RRs, we propose that backbone flexibility is critical to the RR phosphorylation. Besides the limited flexibility, ETR1-RD has a unique γ loop conformation of opposite orientation, which makes ETR1-RD unfavorable for phosphorylation. These two features explain why ETR1-RD cannot be phosphorylated and is classified as an atypical type RR. As a control, phosphorylation of the ETR1-RD was also impaired when the sequence was swapped to the fragment of the bacterial typical type RR, CheY. Here, we suggest a molecule insight that the ETR1-RD already exists as an active formation and executes its function through binding with the downstream factors without phosphorylation.
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Affiliation(s)
- Yi-Lin Hung
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
- Instrumentation Center, National Tsing Hua University, Hsinchu, Taiwan
| | - Ingjye Jiang
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Yi-Zong Lee
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Chi-Kuang Wen
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Shih-Che Sue
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
- Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan
- * E-mail:
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22
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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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23
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Li YH, Wu QS, Huang X, Liu SH, Zhang HN, Zhang Z, Sun GM. Molecular Cloning and Characterization of Four Genes Encoding Ethylene Receptors Associated with Pineapple (Ananas comosus L.) Flowering. FRONTIERS IN PLANT SCIENCE 2016; 7:710. [PMID: 27252725 PMCID: PMC4878293 DOI: 10.3389/fpls.2016.00710] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 05/09/2016] [Indexed: 05/29/2023]
Abstract
Exogenous ethylene, or ethephon, has been widely used to induce pineapple flowering, but the molecular mechanism behind ethephon induction is still unclear. In this study, we cloned four genes encoding ethylene receptors (designated AcERS1a, AcERS1b, AcETR2a, and AcETR2b). The 5' flanking sequences of these four genes were also cloned by self-formed adaptor PCR and SiteFinding-PCR, and a group of putative cis-acting elements was identified. Phylogenetic tree analysis indicated that AcERS1a, AcERS1b, AcETR2a, and AcETR2b belonged to the plant ERS1s and ETR2/EIN4-like groups. Quantitative real-time PCR showed that AcETR2a and AcETR2b (subfamily 2) were more sensitive to ethylene treatment compared with AcERS1a and AcERS1b (subfamily 1). The relative expression of AcERS1b, AcETR2a, and AcETR2b was significantly increased during the earlier period of pineapple inflorescence formation, especially at 1-9 days after ethylene treatment (DAET), whereas AcERS1a expression changed less than these three genes. In situ hybridization results showed that bract primordia (BP) and flower primordia (FP) appeared at 9 and 21 DAET, respectively, and flowers were formed at 37 DAET. AcERS1a, AcERS1b, AcETR2a, and AcETR2b were mainly expressed in the shoot apex at 1-4 DAET; thereafter, with the appearance of BP and FP, higher expression of these genes was found in these new structures. Finally, at 37 DAET, the expression of these genes was mainly focused in the flower but was also low in other structures. These findings indicate that these four ethylene receptor genes, especially AcERS1b, AcETR2a, and AcETR2b, play important roles during pineapple flowering induced by exogenous ethephon.
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Affiliation(s)
- Yun-He Li
- South Subtropical Crop Research Institute, Chinese Academy of Tropical Agricultural SciencesZhanjiang, China
- Key Laboratory of Tropical Fruit Biology, Ministry of AgricultureZhanjiang, China
| | - Qing-Song Wu
- South Subtropical Crop Research Institute, Chinese Academy of Tropical Agricultural SciencesZhanjiang, China
| | - Xia Huang
- The Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen UniversityGuangzhou, China
| | - Sheng-Hui Liu
- South Subtropical Crop Research Institute, Chinese Academy of Tropical Agricultural SciencesZhanjiang, China
| | - Hong-Na Zhang
- South Subtropical Crop Research Institute, Chinese Academy of Tropical Agricultural SciencesZhanjiang, China
| | - Zhi Zhang
- South Subtropical Crop Research Institute, Chinese Academy of Tropical Agricultural SciencesZhanjiang, China
| | - Guang-Ming Sun
- South Subtropical Crop Research Institute, Chinese Academy of Tropical Agricultural SciencesZhanjiang, China
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24
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Prescott AM, McCollough FW, Eldreth BL, Binder BM, Abel SM. Analysis of Network Topologies Underlying Ethylene Growth Response Kinetics. FRONTIERS IN PLANT SCIENCE 2016; 7:1308. [PMID: 27625669 PMCID: PMC5003821 DOI: 10.3389/fpls.2016.01308] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 08/16/2016] [Indexed: 05/04/2023]
Abstract
Most models for ethylene signaling involve a linear pathway. However, measurements of seedling growth kinetics when ethylene is applied and removed have resulted in more complex network models that include coherent feedforward, negative feedback, and positive feedback motifs. The dynamical responses of the proposed networks have not been explored in a quantitative manner. Here, we explore (i) whether any of the proposed models are capable of producing growth-response behaviors consistent with experimental observations and (ii) what mechanistic roles various parts of the network topologies play in ethylene signaling. To address this, we used computational methods to explore two general network topologies: The first contains a coherent feedforward loop that inhibits growth and a negative feedback from growth onto itself (CFF/NFB). In the second, ethylene promotes the cleavage of EIN2, with the product of the cleavage inhibiting growth and promoting the production of EIN2 through a positive feedback loop (PFB). Since few network parameters for ethylene signaling are known in detail, we used an evolutionary algorithm to explore sets of parameters that produce behaviors similar to experimental growth response kinetics of both wildtype and mutant seedlings. We generated a library of parameter sets by independently running the evolutionary algorithm many times. Both network topologies produce behavior consistent with experimental observations, and analysis of the parameter sets allows us to identify important network interactions and parameter constraints. We additionally screened these parameter sets for growth recovery in the presence of sub-saturating ethylene doses, which is an experimentally-observed property that emerges in some of the evolved parameter sets. Finally, we probed simplified networks maintaining key features of the CFF/NFB and PFB topologies. From this, we verified observations drawn from the larger networks about mechanisms underlying ethylene signaling. Analysis of each network topology results in predictions about changes that occur in network components that can be experimentally tested to give insights into which, if either, network underlies ethylene responses.
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Affiliation(s)
- Aaron M. Prescott
- Department of Chemical and Biomolecular Engineering, University of TennesseeKnoxville, TN, USA
| | - Forest W. McCollough
- Department of Biochemistry and Cellular and Molecular Biology, University of TennesseeKnoxville, TN, USA
| | - Bryan L. Eldreth
- Department of Chemical and Biomolecular Engineering, University of TennesseeKnoxville, TN, USA
| | - Brad M. Binder
- Department of Biochemistry and Cellular and Molecular Biology, University of TennesseeKnoxville, TN, USA
- *Correspondence: Brad M. Binder
| | - Steven M. Abel
- Department of Chemical and Biomolecular Engineering, University of TennesseeKnoxville, TN, USA
- National Institute for Mathematical and Biological Synthesis, University of TennesseeKnoxville, TN, USA
- Steven M. Abel
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Ju C, Chang C. Mechanistic Insights in Ethylene Perception and Signal Transduction. PLANT PHYSIOLOGY 2015; 169:85-95. [PMID: 26246449 PMCID: PMC4577421 DOI: 10.1104/pp.15.00845] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 08/05/2015] [Indexed: 05/04/2023]
Abstract
The gaseous hormone ethylene profoundly affects plant growth, development, and stress responses. Ethylene perception occurs at the endoplasmic reticulum membrane, and signal transduction leads to a transcriptional cascade that initiates diverse responses, often in conjunction with other signals. Recent findings provide a more complete picture of the components and mechanisms in ethylene signaling, now rendering a more dynamic view of this conserved pathway. This includes newly identified protein-protein interactions at the endoplasmic reticulum membrane, as well as the major discoveries that the central regulator ETHYLENE INSENSITIVE2 (EIN2) is the long-sought phosphorylation substrate for the CONSTITUTIVE RESPONSE1 protein kinase, and that cleavage of EIN2 transmits the signal to the nucleus. In the nucleus, hundreds of potential gene targets of the EIN3 master transcription factor have been identified and found to be induced in transcriptional waves, and transcriptional coregulation has been shown to be a mechanism of ethylene cross talk.
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Affiliation(s)
- Chuanli Ju
- College of Life Sciences, Capital Normal University, Beijing 100048, China (C.J.); andDepartment of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (C.J., C.C.)
| | - Caren Chang
- College of Life Sciences, Capital Normal University, Beijing 100048, China (C.J.); andDepartment of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (C.J., C.C.)
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Street IH, Aman S, Zubo Y, Ramzan A, Wang X, Shakeel SN, Kieber JJ, Schaller GE. Ethylene Inhibits Cell Proliferation of the Arabidopsis Root Meristem. PLANT PHYSIOLOGY 2015; 169:338-50. [PMID: 26149574 PMCID: PMC4577392 DOI: 10.1104/pp.15.00415] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 07/04/2015] [Indexed: 05/18/2023]
Abstract
The root system of plants plays a critical role in plant growth and survival, with root growth being dependent on both cell proliferation and cell elongation. Multiple phytohormones interact to control root growth, including ethylene, which is primarily known for its role in controlling root cell elongation. We find that ethylene also negatively regulates cell proliferation at the root meristem of Arabidopsis (Arabidopsis thaliana). Genetic analysis indicates that the inhibition of cell proliferation involves two pathways operating downstream of the ethylene receptors. The major pathway is the canonical ethylene signal transduction pathway that incorporates CONSTITUTIVE TRIPLE RESPONSE1, ETHYLENE INSENSITIVE2, and the ETHYLENE INSENSITIVE3 family of transcription factors. The secondary pathway is a phosphorelay based on genetic analysis of receptor histidine kinase activity and mutants involving the type B response regulators. Analysis of ethylene-dependent gene expression and genetic analysis supports SHORT HYPOCOTYL2, a repressor of auxin signaling, as one mediator of the ethylene response and furthermore, indicates that SHORT HYPOCOTYL2 is a point of convergence for both ethylene and cytokinin in negatively regulating cell proliferation. Additional analysis indicates that ethylene signaling contributes but is not required for cytokinin to inhibit activity of the root meristem. These results identify key elements, along with points of cross talk with cytokinin and auxin, by which ethylene negatively regulates cell proliferation at the root apical meristem.
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Affiliation(s)
- Ian H Street
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755 (I.H.S., S.A., Y.Z., A.R., X.W., G.E.S.); Department of Biochemistry, Quaid-i-azam University, Islamabad 45320, Pakistan (S.A., A.R., S.N.S.); and Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.)
| | - Sitwat Aman
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755 (I.H.S., S.A., Y.Z., A.R., X.W., G.E.S.); Department of Biochemistry, Quaid-i-azam University, Islamabad 45320, Pakistan (S.A., A.R., S.N.S.); and Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.)
| | - Yan Zubo
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755 (I.H.S., S.A., Y.Z., A.R., X.W., G.E.S.); Department of Biochemistry, Quaid-i-azam University, Islamabad 45320, Pakistan (S.A., A.R., S.N.S.); and Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.)
| | - Aleena Ramzan
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755 (I.H.S., S.A., Y.Z., A.R., X.W., G.E.S.); Department of Biochemistry, Quaid-i-azam University, Islamabad 45320, Pakistan (S.A., A.R., S.N.S.); and Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.)
| | - Xiaomin Wang
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755 (I.H.S., S.A., Y.Z., A.R., X.W., G.E.S.); Department of Biochemistry, Quaid-i-azam University, Islamabad 45320, Pakistan (S.A., A.R., S.N.S.); and Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.)
| | - Samina N Shakeel
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755 (I.H.S., S.A., Y.Z., A.R., X.W., G.E.S.); Department of Biochemistry, Quaid-i-azam University, Islamabad 45320, Pakistan (S.A., A.R., S.N.S.); and Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.)
| | - Joseph J Kieber
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755 (I.H.S., S.A., Y.Z., A.R., X.W., G.E.S.); Department of Biochemistry, Quaid-i-azam University, Islamabad 45320, Pakistan (S.A., A.R., S.N.S.); and Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.)
| | - G Eric Schaller
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755 (I.H.S., S.A., Y.Z., A.R., X.W., G.E.S.); Department of Biochemistry, Quaid-i-azam University, Islamabad 45320, Pakistan (S.A., A.R., S.N.S.); and Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.)
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Bakshi A, Wilson RL, Lacey RF, Kim H, Wuppalapati SK, Binder BM. Identification of Regions in the Receiver Domain of the ETHYLENE RESPONSE1 Ethylene Receptor of Arabidopsis Important for Functional Divergence. PLANT PHYSIOLOGY 2015; 169:219-32. [PMID: 26160962 PMCID: PMC4577405 DOI: 10.1104/pp.15.00626] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 07/09/2015] [Indexed: 05/08/2023]
Abstract
Ethylene influences the growth and development of Arabidopsis (Arabidopsis thaliana) via five receptor isoforms. However, the ETHYLENE RESPONSE1 (ETR1) ethylene receptor has unique, and sometimes contrasting, roles from the other receptor isoforms. Prior research indicates that the receiver domain of ETR1 is important for some of these noncanonical roles. We determined that the ETR1 receiver domain is not needed for ETR1's predominant role in mediating responses to the ethylene antagonist, silver. To understand the structure-function relationship underlying the unique roles of the ETR1 receiver domain in the control of specific traits, we performed alanine-scanning mutagenesis. We chose amino acids that are poorly conserved and are in regions predicted to have altered tertiary structure compared with the receiver domains of the other two receptors that contain a receiver domain, ETR2 and ETHYLENE INSENSITIVE4. The effects of these mutants on various phenotypes were examined in transgenic, receptor-deficient Arabidopsis plants. Some traits, such as growth in air and growth recovery after the removal of ethylene, were unaffected by these mutations. By contrast, three mutations on one surface of the receiver domain rendered the transgene unable to rescue ethylene-stimulated nutations. Additionally, several mutations on another surface altered germination on salt. Some of these mutations conferred hyperfunctionality to ETR1 in the context of seed germination on salt, but not for other traits, that correlated with increased responsiveness to abscisic acid. Thus, the ETR1 receiver domain has multiple functions where different surfaces are involved in the control of different traits. Models are discussed for these observations.
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Affiliation(s)
- Arkadipta Bakshi
- Genome Science and Technology Program (A.B., B.M.B.) and Department of Biochemistry, Cellular, and Molecular Biology (R.L.W., R.F.L., H.K., S.K.W., B.M.B.), University of Tennessee, Knoxville, Tennessee 37996
| | - Rebecca L Wilson
- Genome Science and Technology Program (A.B., B.M.B.) and Department of Biochemistry, Cellular, and Molecular Biology (R.L.W., R.F.L., H.K., S.K.W., B.M.B.), University of Tennessee, Knoxville, Tennessee 37996
| | - Randy F Lacey
- Genome Science and Technology Program (A.B., B.M.B.) and Department of Biochemistry, Cellular, and Molecular Biology (R.L.W., R.F.L., H.K., S.K.W., B.M.B.), University of Tennessee, Knoxville, Tennessee 37996
| | - Heejung Kim
- Genome Science and Technology Program (A.B., B.M.B.) and Department of Biochemistry, Cellular, and Molecular Biology (R.L.W., R.F.L., H.K., S.K.W., B.M.B.), University of Tennessee, Knoxville, Tennessee 37996
| | - Sai Keerthana Wuppalapati
- Genome Science and Technology Program (A.B., B.M.B.) and Department of Biochemistry, Cellular, and Molecular Biology (R.L.W., R.F.L., H.K., S.K.W., B.M.B.), University of Tennessee, Knoxville, Tennessee 37996
| | - Brad M Binder
- Genome Science and Technology Program (A.B., B.M.B.) and Department of Biochemistry, Cellular, and Molecular Biology (R.L.W., R.F.L., H.K., S.K.W., B.M.B.), University of Tennessee, Knoxville, Tennessee 37996
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28
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Rai MI, Wang X, Thibault DM, Kim HJ, Bombyk MM, Binder BM, Shakeel SN, Schaller GE. The ARGOS gene family functions in a negative feedback loop to desensitize plants to ethylene. BMC PLANT BIOLOGY 2015; 15:157. [PMID: 26105742 PMCID: PMC4478640 DOI: 10.1186/s12870-015-0554-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 06/15/2015] [Indexed: 05/21/2023]
Abstract
BACKGROUND Ethylene plays critical roles in plant growth and development, including the regulation of cell expansion, senescence, and the response to biotic and abiotic stresses. Elements of the initial signal transduction pathway have been determined, but we are still defining regulatory mechanisms by which the sensitivity of plants to ethylene is modulated. RESULTS We report here that members of the ARGOS gene family of Arabidopsis, previously implicated in the regulation of plant growth and biomass, function as negative feedback regulators of ethylene signaling. Expression of all four members of the ARGOS family is induced by ethylene, but this induction is blocked in ethylene-insensitive mutants. The dose dependence for ethylene induction varies among the ARGOS family members, suggesting that they could modulate responses across a range of ethylene concentrations. GFP-fusions of ARGOS and ARL localize to the endoplasmic reticulum, the same subcellular location as the ethylene receptors and other initial components of the ethylene signaling pathway. Seedlings with increased expression of ARGOS family members exhibit reduced ethylene sensitivity based on physiological and molecular responses. CONCLUSIONS These results support a model in which the ARGOS gene family functions as part of a negative feedback circuit to desensitize the plant to ethylene, thereby expanding the range of ethylene concentrations to which the plant can respond. These results also indicate that the effects of the ARGOS gene family on plant growth and biomass are mediated through effects on ethylene signal transduction.
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Affiliation(s)
- Muneeza Iqbal Rai
- 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.
| | - Derek M Thibault
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA.
| | - Hyo Jung Kim
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA.
| | - Matthew M Bombyk
- 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.
| | - Samina N Shakeel
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA.
- Department of Biochemistry, Quaid-i-azam University, Islamabad, 45320, Pakistan.
| | - G Eric Schaller
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA.
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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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30
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Shakeel SN, Gao Z, Amir M, Chen YF, Rai MI, Haq NU, Schaller GE. Ethylene Regulates Levels of Ethylene Receptor/CTR1 Signaling Complexes in Arabidopsis thaliana. J Biol Chem 2015; 290:12415-24. [PMID: 25814663 DOI: 10.1074/jbc.m115.652503] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Indexed: 11/06/2022] Open
Abstract
The plant hormone ethylene is perceived by a five-member family of receptors in Arabidopsis thaliana. The receptors function in conjunction with the Raf-like kinase CTR1 to negatively regulate ethylene signal transduction. CTR1 interacts with multiple members of the receptor family based on co-purification analysis, interacting more strongly with receptors containing a receiver domain. Levels of membrane-associated CTR1 vary in response to ethylene, doing so in a post-transcriptional manner that correlates with ethylene-mediated changes in levels of the ethylene receptors ERS1, ERS2, EIN4, and ETR2. Interactions between CTR1 and the receptor ETR1 protect ETR1 from ethylene-induced turnover. Kinetic and dose-response analyses support a model in which two opposing factors control levels of the ethylene receptor/CTR1 complexes. Ethylene stimulates the production of new complexes largely through transcriptional induction of the receptors. However, ethylene also induces turnover of receptors, such that levels of ethylene receptor/CTR1 complexes decrease at higher ethylene concentrations. Implications of this model for ethylene signaling are discussed.
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Affiliation(s)
- Samina N Shakeel
- From the Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, the Department of Biochemistry, Quaid-i-azam University, Islamabad, 45320, Pakistan, and
| | - Zhiyong Gao
- From the Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
| | - Madiha Amir
- From the Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, the Department of Biochemistry, Quaid-i-azam University, Islamabad, 45320, Pakistan, and
| | - Yi-Feng Chen
- From the Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, the Institute of Biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, People's Republic of China
| | - Muneeza Iqbal Rai
- From the Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, the Department of Biochemistry, Quaid-i-azam University, Islamabad, 45320, Pakistan, and
| | - Noor Ul Haq
- From the Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, the Department of Biochemistry, Quaid-i-azam University, Islamabad, 45320, Pakistan, and
| | - G Eric Schaller
- From the Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755,
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Kim J, Chang C, Tucker ML. To grow old: regulatory role of ethylene and jasmonic acid in senescence. FRONTIERS IN PLANT SCIENCE 2015; 6:20. [PMID: 25688252 PMCID: PMC4310285 DOI: 10.3389/fpls.2015.00020] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 01/10/2015] [Indexed: 05/18/2023]
Abstract
Senescence, the final stage in the development of an organ or whole plant, is a genetically programmed process controlled by developmental and environmental signals. Age-related signals underlie the onset of senescence in specific organs (leaf, flower, and fruit) as well as the whole plant (monocarpic senescence). Rudimentary to most senescence processes is the plant hormone ethylene, a small gaseous molecule critical to diverse processes throughout the life of the plant. The role of ethylene in senescence was discovered almost 100 years ago, but the molecular mechanisms by which ethylene regulates senescence have been deciphered more recently primarily through genetic and molecular studies in Arabidopsis. Jasmonic acid (JA), another plant hormone, is emerging as a key player in the control of senescence. The regulatory network of ethylene and JA involves the integration of transcription factors, microRNAs, and other hormones. In this review, we summarize the current understanding of ethylene's role in senescence, and discuss the interplay of ethylene with JA in the regulation of senescence.
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Affiliation(s)
- Joonyup Kim
- Soybean Genomics and Improvement Laboratory, United States Department of Agriculture–Agricultural Research Service, Beltsville, MD, USA
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
- *Correspondence: Joonyup Kim and Mark L. Tucker, Soybean Genomics and Improvement Laboratory, United States Department of Agriculture–Agricultural Research Service, 10300 Baltimore Avenue, Building 006, Room 212, BARC-WEST, Beltsville, MD 20705, USA e-mail: ;
| | - Caren Chang
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | - Mark L. Tucker
- Soybean Genomics and Improvement Laboratory, United States Department of Agriculture–Agricultural Research Service, Beltsville, MD, USA
- *Correspondence: Joonyup Kim and Mark L. Tucker, Soybean Genomics and Improvement Laboratory, United States Department of Agriculture–Agricultural Research Service, 10300 Baltimore Avenue, Building 006, Room 212, BARC-WEST, Beltsville, MD 20705, USA e-mail: ;
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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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33
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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: 81] [Impact Index Per Article: 8.1] [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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Kim HJ, Hong SH, Kim YW, Lee IH, Jun JH, Phee BK, Rupak T, Jeong H, Lee Y, Hong BS, Nam HG, Woo HR, Lim PO. Gene regulatory cascade of senescence-associated NAC transcription factors activated by ETHYLENE-INSENSITIVE2-mediated leaf senescence signalling in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:4023-36. [PMID: 24659488 PMCID: PMC4106440 DOI: 10.1093/jxb/eru112] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Leaf senescence is a finely tuned and genetically programmed degeneration process, which is critical to maximize plant fitness by remobilizing nutrients from senescing leaves to newly developing organs. Leaf senescence is a complex process that is driven by extensive reprogramming of global gene expression in a highly coordinated manner. Understanding how gene regulatory networks involved in controlling leaf senescence are organized and operated is essential to decipher the mechanisms of leaf senescence. It was previously reported that the trifurcate feed-forward pathway involving EIN2, ORE1, and miR164 in Arabidopsis regulates age-dependent leaf senescence and cell death. Here, new components of this pathway have been identified, which enhances knowledge of the gene regulatory networks governing leaf senescence. Comparative gene expression analysis revealed six senescence-associated NAC transcription factors (TFs) (ANAC019, AtNAP, ANAC047, ANAC055, ORS1, and ORE1) as candidate downstream components of ETHYLENE-INSENSITIVE2 (EIN2). EIN3, a downstream signalling molecule of EIN2, directly bound the ORE1 and AtNAP promoters and induced their transcription. This suggests that EIN3 positively regulates leaf senescence by activating ORE1 and AtNAP, previously reported as key regulators of leaf senescence. Genetic and gene expression analyses in the ore1 atnap double mutant revealed that ORE1 and AtNAP act in distinct and overlapping signalling pathways. Transient transactivation assays further demonstrated that ORE1 and AtNAP could activate common as well as differential NAC TF targets. Collectively, the data provide insight into an EIN2-mediated senescence signalling pathway that coordinates global gene expression during leaf senescence via a gene regulatory network involving EIN3 and senescence-associated NAC TFs.
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Affiliation(s)
- Hyo Jung Kim
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu 711-873, Republic of Korea
| | - Sung Hyun Hong
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu 711-873, Republic of Korea
| | - You Wang Kim
- Department of New Biology, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 711-873, Republic of Korea
| | - Il Hwan Lee
- Department of Life Sciences, POSTECH, Pohang, Gyeongbuk 790-784, Republic of Korea
| | - Ji Hyung Jun
- Department of Life Sciences, POSTECH, Pohang, Gyeongbuk 790-784, Republic of Korea
| | - Bong-Kwan Phee
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu 711-873, Republic of Korea
| | - Timilsina Rupak
- School of Interdisciplinary Bioscience and Bioengineering, POSTECH, Pohang, Gyeongbuk 790-784, Republic of Korea
| | - Hana Jeong
- Department of New Biology, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 711-873, Republic of Korea
| | - Yeonmi Lee
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu 711-873, Republic of Korea
| | - Byoung Seok Hong
- Department of New Biology, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 711-873, Republic of Korea
| | - Hong Gil Nam
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu 711-873, Republic of Korea Department of New Biology, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 711-873, Republic of Korea
| | - Hye Ryun Woo
- Department of New Biology, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 711-873, Republic of Korea
| | - Pyung Ok Lim
- Department of New Biology, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 711-873, Republic of Korea
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35
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Smet D, Žádníková P, Vandenbussche F, Benková E, Van Der Straeten D. Dynamic infrared imaging analysis of apical hook development in Arabidopsis: the case of brassinosteroids. THE NEW PHYTOLOGIST 2014; 202:1398-1411. [PMID: 24611517 DOI: 10.1111/nph.12751] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 02/03/2014] [Indexed: 05/06/2023]
Abstract
Germination of Arabidopsis seeds in darkness induces apical hook development, based on a tightly regulated differential growth coordinated by a multiple hormone cross-talk. Here, we endeavoured to clarify the function of brassinosteroids (BRs) and cross-talk with ethylene in hook development. An automated infrared imaging system was developed to study the kinetics of hook development in etiolated Arabidopsis seedlings. To ascertain the photomorphogenic control of hook opening, the system was equipped with an automatic light dimmer. We demonstrate that ethylene and BRs are indispensable for hook formation and maintenance. Ethylene regulation of hook formation functions partly through BRs, with BR feedback inhibition of ethylene action. Conversely, BR-mediated extension of hook maintenance functions partly through ethylene. Furthermore, we revealed that a short light pulse is sufficient to induce rapid hook opening. Our dynamic infrared imaging system allows high-resolution, kinetic imaging of up to 112 seedlings in a single experimental run. At this high throughput, it is ideally suited to rapidly gain insight in pathway networks. We demonstrate that BRs and ethylene cooperatively regulate apical hook development in a phase-dependent manner. Furthermore, we show that light is a predominant regulator of hook opening, inhibiting ethylene- and BR-mediated postponement of hook opening.
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Affiliation(s)
- Dajo Smet
- Laboratory of Functional Plant Biology, Department of Physiology, Ghent University, 9000, Gent, Belgium
| | - Petra Žádníková
- Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052, Gent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
| | - Filip Vandenbussche
- Laboratory of Functional Plant Biology, Department of Physiology, Ghent University, 9000, Gent, Belgium
| | - Eva Benková
- Institute of Science and Technology, 3400, Klosterneuburg, Austria
- Genomics and Proteomics of Plant Systems, Central European Institute of Technology, Masaryk University, 62500, Brno, Czech Republic
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36
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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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37
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Böttcher C, Burbidge CA, Boss PK, Davies C. Interactions between ethylene and auxin are crucial to the control of grape (Vitis vinifera L.) berry ripening. BMC PLANT BIOLOGY 2013; 13:222. [PMID: 24364881 PMCID: PMC3878033 DOI: 10.1186/1471-2229-13-222] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 12/20/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND Fruit development is controlled by plant hormones, but the role of hormone interactions during fruit ripening is poorly understood. Interactions between ethylene and the auxin indole-3-acetic acid (IAA) are likely to be crucial during the ripening process, since both hormones have been shown to be implicated in the control of ripening in a range of different fruit species. RESULTS Grapevine (Vitis vinifera L.) homologues of the TRYPTOPHAN AMINOTRANSFERASE RELATED (TAR) and YUCCA families, functioning in the only characterized pathway of auxin biosynthesis, were identified and the expression of several TAR genes was shown to be induced by the pre-ripening application of the ethylene-releasing compound Ethrel. The induction of TAR expression was accompanied by increased IAA and IAA-Asp concentrations, indicative of an upregulation of auxin biosynthesis and conjugation. Exposure of ex planta, pre-ripening berries to the ethylene biosynthesis inhibitor aminoethoxyvinylglycine resulted in decreased IAA and IAA-Asp concentrations. The delayed initiation of ripening observed in Ethrel-treated berries might therefore represent an indirect ethylene effect mediated by increased auxin concentrations. During berry development, the expression of three TAR genes and one YUCCA gene was upregulated at the time of ripening initiation and/or during ripening. This increase in auxin biosynthesis gene expression was preceded by high expression levels of the ethylene biosynthesis genes 1-aminocyclopropane-1-carboxylate synthase and 1-aminocyclopropane-1-carboxylate oxidase. CONCLUSIONS In grape berries, members of both gene families involved in the two-step pathway of auxin biosynthesis are expressed, suggesting that IAA is produced through the combined action of TAR and YUCCA proteins in developing berries. The induction of TAR expression by Ethrel applications and the developmental expression patterns of auxin and ethylene biosynthesis genes indicate that elevated concentrations of ethylene prior to the initiation of ripening might lead to an increased production of IAA, suggesting a complex involvement of this auxin and its conjugates in grape berry ripening.
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Affiliation(s)
| | | | - Paul K Boss
- CSIRO Plant Industry, PO Box 350, Glen Osmond, SA 5064, Australia
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38
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Markakis MN, Boron AK, Van Loock B, Saini K, Cirera S, Verbelen JP, Vissenberg K. Characterization of a small auxin-up RNA (SAUR)-like gene involved in Arabidopsis thaliana development. PLoS One 2013; 8:e82596. [PMID: 24312429 PMCID: PMC3842426 DOI: 10.1371/journal.pone.0082596] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 11/03/2013] [Indexed: 12/19/2022] Open
Abstract
The root of Arabidopsis thaliana is used as a model system to unravel the molecular nature of cell elongation and its arrest. From a micro-array performed on roots that were treated with aminocyclopropane-1-carboxylic acid (ACC), the precursor of ethylene, a Small auxin-up RNA (SAUR)-like gene was found to be up regulated. As it appeared as the 76th gene in the family, it was named SAUR76. Root and leaf growth of overexpression lines ectopically expressing SAUR76 indicated the possible involvement of the gene in the division process. Using promoter::GUS and GFP lines strong expression was seen in endodermal and pericycle cells at the end of the elongation zone and during several stages of lateral root primordia development. ACC and IAA/NAA were able to induce a strong up regulation of the gene and changed the expression towards cortical and even epidermal cells at the beginning of the elongation zone. Confirmation of this up regulation of expression was delivered using qPCR, which also indicated that the expression quickly returned to normal levels when the inducing IAA-stimulus was removed, a behaviour also seen in other SAUR genes. Furthermore, confocal analysis of protein-GFP fusions localized the protein in the nucleus, cytoplasm and plasma membrane. SAUR76 expression was quantified in several mutants in ethylene and auxin-related pathways, which led to the conclusion that the expression of SAUR76 is mainly regulated by the increase in auxin that results from the addition of ACC, rather than by ACC itself.
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Affiliation(s)
| | | | - Bram Van Loock
- Department of Biology, University of Antwerp, Antwerpen, Belgium
| | - Kumud Saini
- Department of Biology, University of Antwerp, Antwerpen, Belgium
| | - Susanna Cirera
- Department of Animal and Veterinary Basic Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | | | - Kris Vissenberg
- Department of Biology, University of Antwerp, Antwerpen, Belgium
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Ma B, He SJ, Duan KX, Yin CC, Chen H, Yang C, Xiong Q, Song QX, Lu X, Chen HW, Zhang WK, Lu TG, Chen SY, Zhang JS. Identification of rice ethylene-response mutants and characterization of MHZ7/OsEIN2 in distinct ethylene response and yield trait regulation. MOLECULAR PLANT 2013; 6:1830-48. [PMID: 23718947 DOI: 10.1093/mp/sst087] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Ethylene plays essential roles in adaptive growth of rice plants in water-saturating environment; however, ethylene signaling pathway in rice is largely unclear. In this study, we report identification and characterization of ethylene-response mutants based on the specific ethylene-response phenotypes of etiolated rice seedlings, including ethylene-inhibited root growth and ethylene-promoted coleoptile elongation, which is different from the ethylene triple-response phenotype in Arabidopsis. We establish an efficient system for screening and a set of rice mutants have been identified. Genetic analysis reveals that these mutants form eight complementation groups. All the mutants show insensitivity or reduced sensitivity to ethylene in root growth but exhibit differential responses in coleoptile growth. One mutant group mhz7 has insensitivity to ethylene in both root and coleoptile growth. We identified the corresponding gene by a map-based cloning method. MHZ7 encodes a membrane protein homologous to EIN2, a central component of ethylene signaling in Arabidopsis. Upon ethylene treatment, etiolated MHZ7-overexpressing seedlings exhibit enhanced coleoptile elongation, increased mesocotyl growth and extremely twisted short roots, featuring enhanced ethylene-response phenotypes in rice. Grain length was promoted in MHZ7-transgenic plants and 1000-grain weight was reduced in mhz7 mutants. Leaf senescent process was also affected by MHZ7 expression. Manipulation of ethylene signaling may improve adaptive growth and yield-related traits in rice.
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Affiliation(s)
- Biao Ma
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
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40
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Mayerhofer H, Mueller-Dieckmann J. Cloning, expression, purification and preliminary X-ray analysis of the dimerization domain of ethylene response sensor 1 (ERS1) from Arabidopsis thaliana. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:1029-32. [PMID: 23989156 PMCID: PMC3758156 DOI: 10.1107/s1744309113021751] [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: 06/27/2013] [Accepted: 08/04/2013] [Indexed: 11/10/2022]
Abstract
Ethylene signalling is initiated by a group of membrane-bound receptors with similarity to two-component systems. ERS1 belongs, together with ETR1, to subfamily 1, which plays a predominant role in ethylene signalling. The dimerization domain of ERS1 was crystallized in space groups C222(1) and P2(1)2(1)2, with two and four molecules per asymmetric unit, respectively. The crystals diffracted X-ray radiation to 1.9 Å resolution.
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Affiliation(s)
- Hubert Mayerhofer
- EMBL Hamburg Outstation, c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany
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41
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Wang F, Cui X, Sun Y, Dong CH. Ethylene signaling and regulation in plant growth and stress responses. PLANT CELL REPORTS 2013; 32:1099-109. [PMID: 23525746 DOI: 10.1007/s00299-013-1421-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Revised: 02/28/2013] [Accepted: 03/09/2013] [Indexed: 05/19/2023]
Abstract
Gaseous phytohormone ethylene affects many aspects of plant growth and development. The ethylene signaling pathway starts when ethylene binds to its receptors. Since the cloning of the first ethylene receptor ETR1 from Arabidopsis, a large number of studies have steadily improved our understanding of the receptors and downstream components in ethylene signal transduction pathway. This article reviews the regulation of ethylene receptors, signal transduction, and the posttranscriptional modulation of downstream components. Functional roles and importance of the ethylene signaling components in plant growth and stress responses are also discussed. Cross-reactions of ethylene with auxin and other phytohormones in plant organ growth will be analyzed. The studies of ethylene signaling in plant growth, development, and stress responses in the past decade greatly advanced our knowledge of how plants respond to endogenous signals and environmental factors.
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Affiliation(s)
- Feifei Wang
- College of Life Sciences, Qingdao Agricultural University, 266109 Qingdao, People's Republic of China
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42
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Chang KN, Zhong S, Weirauch MT, Hon G, Pelizzola M, Li H, Huang SSC, Schmitz RJ, Urich MA, Kuo D, Nery JR, Qiao H, Yang A, Jamali A, Chen H, Ideker T, Ren B, Bar-Joseph Z, Hughes TR, Ecker JR. Temporal transcriptional response to ethylene gas drives growth hormone cross-regulation in Arabidopsis. eLife 2013. [PMID: 23795294 DOI: 10.7554/elife.00675.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023] Open
Abstract
The gaseous plant hormone ethylene regulates a multitude of growth and developmental processes. How the numerous growth control pathways are coordinated by the ethylene transcriptional response remains elusive. We characterized the dynamic ethylene transcriptional response by identifying targets of the master regulator of the ethylene signaling pathway, ETHYLENE INSENSITIVE3 (EIN3), using chromatin immunoprecipitation sequencing and transcript sequencing during a timecourse of ethylene treatment. Ethylene-induced transcription occurs in temporal waves regulated by EIN3, suggesting distinct layers of transcriptional control. EIN3 binding was found to modulate a multitude of downstream transcriptional cascades, including a major feedback regulatory circuitry of the ethylene signaling pathway, as well as integrating numerous connections between most of the hormone mediated growth response pathways. These findings provide direct evidence linking each of the major plant growth and development networks in novel ways. DOI:http://dx.doi.org/10.7554/eLife.00675.001.
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Affiliation(s)
- Katherine Noelani Chang
- Plant Biology Laboratory, and Genomic Analysis Laboratory , The Salk Institute for Biological Studies , La Jolla , United States
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43
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Chang KN, Zhong S, Weirauch MT, Hon G, Pelizzola M, Li H, Huang SSC, Schmitz RJ, Urich MA, Kuo D, Nery JR, Qiao H, Yang A, Jamali A, Chen H, Ideker T, Ren B, Bar-Joseph Z, Hughes TR, Ecker JR. Temporal transcriptional response to ethylene gas drives growth hormone cross-regulation in Arabidopsis. eLife 2013; 2:e00675. [PMID: 23795294 DOI: 10.7554/elife.00675.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/08/2013] [Indexed: 05/25/2023] Open
Abstract
The gaseous plant hormone ethylene regulates a multitude of growth and developmental processes. How the numerous growth control pathways are coordinated by the ethylene transcriptional response remains elusive. We characterized the dynamic ethylene transcriptional response by identifying targets of the master regulator of the ethylene signaling pathway, ETHYLENE INSENSITIVE3 (EIN3), using chromatin immunoprecipitation sequencing and transcript sequencing during a timecourse of ethylene treatment. Ethylene-induced transcription occurs in temporal waves regulated by EIN3, suggesting distinct layers of transcriptional control. EIN3 binding was found to modulate a multitude of downstream transcriptional cascades, including a major feedback regulatory circuitry of the ethylene signaling pathway, as well as integrating numerous connections between most of the hormone mediated growth response pathways. These findings provide direct evidence linking each of the major plant growth and development networks in novel ways. DOI:http://dx.doi.org/10.7554/eLife.00675.001.
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Affiliation(s)
- Katherine Noelani Chang
- Plant Biology Laboratory, and Genomic Analysis Laboratory , The Salk Institute for Biological Studies , La Jolla , United States
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44
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Chang KN, Zhong S, Weirauch MT, Hon G, Pelizzola M, Li H, Huang SSC, Schmitz RJ, Urich MA, Kuo D, Nery JR, Qiao H, Yang A, Jamali A, Chen H, Ideker T, Ren B, Bar-Joseph Z, Hughes TR, Ecker JR. Temporal transcriptional response to ethylene gas drives growth hormone cross-regulation in Arabidopsis. eLife 2013; 2:e00675. [PMID: 23795294 PMCID: PMC3679525 DOI: 10.7554/elife.00675] [Citation(s) in RCA: 281] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/08/2013] [Indexed: 12/12/2022] Open
Abstract
The gaseous plant hormone ethylene regulates a multitude of growth and developmental processes. How the numerous growth control pathways are coordinated by the ethylene transcriptional response remains elusive. We characterized the dynamic ethylene transcriptional response by identifying targets of the master regulator of the ethylene signaling pathway, ETHYLENE INSENSITIVE3 (EIN3), using chromatin immunoprecipitation sequencing and transcript sequencing during a timecourse of ethylene treatment. Ethylene-induced transcription occurs in temporal waves regulated by EIN3, suggesting distinct layers of transcriptional control. EIN3 binding was found to modulate a multitude of downstream transcriptional cascades, including a major feedback regulatory circuitry of the ethylene signaling pathway, as well as integrating numerous connections between most of the hormone mediated growth response pathways. These findings provide direct evidence linking each of the major plant growth and development networks in novel ways. DOI:http://dx.doi.org/10.7554/eLife.00675.001 All multicellular organisms, including plants, produce hormones—chemical messengers that are released in one part of an organism but act in another. The binding of hormones to receptor proteins on the surface of target cells activates signal transduction cascades, leading ultimately to changes in the transcription and translation of genes. Ethylene is a gaseous plant hormone that acts at trace levels to stimulate or regulate a variety of processes, including the regulation of plant growth, the ripening of fruit and the shedding of leaves. Plants also produce ethylene in response to wounding, pathogen attack or exposure to environmental stresses, such as extreme temperatures or drought. Although the effects of ethylene on plants are well documented, much less is known about how its functions are controlled and coordinated at the molecular level. Here, Chang et al. reveal how ethylene alters the transcription of DNA into messenger DNA (mRNA) in the plant model organism, Arabidopsis thaliana. Ethylene is known to exert some of its effects via a protein called EIN3, which is a transcription factor that acts as the master regulator of the ethylene signaling pathway. To identify the targets of EIN3, Chang et al. exposed plants to ethylene and then used a technique called ChIP-Seq to identify those regions of the DNA that EIN3 binds to. At the same time, they used genome-wide mRNA sequencing to determine which genes showed altered transcription. Over the course of 24 hr, ethylene induced four distinct waves of transcription, suggesting that discrete layers of transcriptional control are present. EIN3 binding also controlled a multitude of downstream transcriptional cascades, including a major negative feedback loop. Surprisingly, many of the genes that showed altered expression in response to EIN3 binding were also influenced by hormones other than ethylene. In addition to extending our knowledge of the role of EIN3 in coordinating the effects of ethylene, the work of Chang et al. reveals the extensive connectivity between pathways regulated by distinct hormones in plants. The results may also make it easier to identify key players involved in hormone signaling pathways in other plant species. DOI:http://dx.doi.org/10.7554/eLife.00675.002
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Affiliation(s)
- Katherine Noelani Chang
- Plant Biology Laboratory, and Genomic Analysis Laboratory , The Salk Institute for Biological Studies , La Jolla , United States
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45
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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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46
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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 DOI: 10.1093/aobpla/plt01010.1093/aobpla/plt010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Accepted: 02/05/2013] [Indexed: 05/20/2023]
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
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47
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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 DOI: 10.1093/aobpla/plt010,1-16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [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
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48
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Kim J, Wilson RL, Case JB, Binder BM. A comparative study of ethylene growth response kinetics in eudicots and monocots reveals a role for gibberellin in growth inhibition and recovery. PLANT PHYSIOLOGY 2012; 160:1567-80. [PMID: 22977279 PMCID: PMC3490611 DOI: 10.1104/pp.112.205799] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Time-lapse imaging of dark-grown Arabidopsis (Arabidopsis thaliana) hypocotyls has revealed new aspects about ethylene signaling. This study expands upon these results by examining ethylene growth response kinetics of seedlings of several plant species. Although the response kinetics varied between the eudicots studied, all had prolonged growth inhibition for as long as ethylene was present. In contrast, with continued application of ethylene, white millet (Panicum miliaceum) seedlings had a rapid and transient growth inhibition response, rice (Oryza sativa 'Nipponbare') seedlings had a slow onset of growth stimulation, and barley (Hordeum vulgare) had a transient growth inhibition response followed, after a delay, by a prolonged inhibition response. Growth stimulation in rice correlated with a decrease in the levels of rice ETHYLENE INSENSTIVE3-LIKE2 (OsEIL2) and an increase in rice F-BOX DOMAIN AND LRR CONTAINING PROTEIN7 transcripts. The gibberellin (GA) biosynthesis inhibitor paclobutrazol caused millet seedlings to have a prolonged growth inhibition response when ethylene was applied. A transient ethylene growth inhibition response has previously been reported for Arabidopsis ethylene insensitive3-1 (ein3-1) eil1-1 double mutants. Paclobutrazol caused these mutants to have a prolonged response to ethylene, whereas constitutive GA signaling in this background eliminated ethylene responses. Sensitivity to paclobutrazol inversely correlated with the levels of EIN3 in Arabidopsis. Wild-type Arabidopsis seedlings treated with paclobutrazol and mutants deficient in GA levels or signaling had a delayed growth recovery after ethylene removal. It is interesting to note that ethylene caused alterations in gene expression that are predicted to increase GA levels in the ein3-1 eil1-1 seedlings. These results indicate that ethylene affects GA levels leading to modulation of ethylene growth inhibition kinetics.
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Bours R, Muthuraman M, Bouwmeester H, van der Krol A. OSCILLATOR: A system for analysis of diurnal leaf growth using infrared photography combined with wavelet transformation. PLANT METHODS 2012; 8:29. [PMID: 22867627 PMCID: PMC3489599 DOI: 10.1186/1746-4811-8-29] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 07/20/2012] [Indexed: 05/08/2023]
Abstract
BACKGROUND Quantification of leaf movement is an important tool for characterising the effects of environmental signals and the circadian clock on plant development. Analysis of leaf movement is currently restricted by the attachment of sensors to the plant or dependent upon visible light for time-lapse photography. The study of leaf growth movement rhythms in mature plants under biological relevant conditions, e.g. diurnal light and dark conditions, is therefore problematic. RESULTS Here we present OSCILLATOR, an affordable system for the analysis of rhythmic leaf growth movement in mature plants. The system contains three modules: (1) Infrared time-lapse imaging of growing mature plants (2) measurement of projected distances between leaf tip and plant apex (leaf tip tracking growth-curves) and (3) extraction of phase, period and amplitude of leaf growth oscillations using wavelet analysis. A proof-of-principle is provided by characterising parameters of rhythmic leaf growth movement of different Arabidopsis thaliana accessions as well as of Petunia hybrida and Solanum lycopersicum plants under diurnal conditions. The amplitude of leaf oscillations correlated to published data on leaf angles, while amplitude and leaf length did not correlate, suggesting a distinct leaf growth profile for each accession. Arabidopsis mutant accession Landsberg erecta displayed a late phase (timing of peak oscillation) compared to other accessions and this trait appears unrelated to the ERECTA locus. CONCLUSIONS OSCILLATOR is a low cost and easy to implement system that can accurately and reproducibly quantify rhythmic growth of mature plants for different species under diurnal light/dark cycling.
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Affiliation(s)
- Ralph Bours
- Laboratory of Plant Physiology, Wageningen University, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands
| | - Manickam Muthuraman
- Laboratory of Plant Physiology, Wageningen University, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands
| | - Harro Bouwmeester
- Laboratory of Plant Physiology, Wageningen University, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands
| | - Alexander van der Krol
- Laboratory of Plant Physiology, Wageningen University, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands
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McDaniel BK, Binder BM. ethylene receptor 1 (etr1) Is Sufficient and Has the Predominant Role in Mediating Inhibition of Ethylene Responses by Silver in Arabidopsis thaliana. J Biol Chem 2012; 287:26094-103. [PMID: 22692214 PMCID: PMC3406693 DOI: 10.1074/jbc.m112.383034] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 06/09/2012] [Indexed: 11/06/2022] Open
Abstract
Ethylene influences many processes in Arabidopsis thaliana through the action of five receptor isoforms. All five isoforms use copper as a cofactor for binding ethylene. Previous research showed that silver can substitute for copper as a cofactor for ethylene binding activity in the ETR1 ethylene receptor yet also inhibit ethylene responses in plants. End-point and rapid kinetic analyses of dark-grown seedling growth revealed that the effects of silver are mostly dependent upon ETR1, and ETR1 alone is sufficient for the effects of silver. Ethylene responses in etr1-6 etr2-3 ein4-4 triple mutants were not blocked by silver. Transformation of these triple mutants with cDNA for each receptor isoform under the promoter control of ETR1 revealed that the cETR1 transgene completely rescued responses to silver while the cETR2 transgene failed to rescue these responses. The other three isoforms partially rescued responses to silver. Ethylene binding assays on the binding domains of the five receptor isoforms expressed in yeast showed that silver supports ethylene binding to ETR1 and ERS1 but not the other isoforms. Thus, silver may have an effect on ethylene signaling outside of the ethylene binding pocket of the receptors. Ethylene binding to ETR1 with silver was ∼30% of binding with copper. However, alterations in the K(d) for ethylene binding to ETR1 and the half-time of ethylene dissociation from ETR1 do not underlie this lower binding. Thus, it is likely that the lower ethylene binding activity of ETR1 with silver is due to fewer ethylene binding sites generated with silver versus copper.
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Affiliation(s)
- Brittany K. McDaniel
- From the Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0849
| | - Brad M. Binder
- From the Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0849
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