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Li M, Sun X, Di D, Zhang A, Qing L, Zhou T, Miao H, Fan Z. Maize AKINβγ Proteins Interact with P8 of Rice Black Streaked Dwarf Virus and Inhibit Viral Infection. Viruses 2020; 12:v12121387. [PMID: 33291518 PMCID: PMC7761811 DOI: 10.3390/v12121387] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 11/27/2020] [Accepted: 11/28/2020] [Indexed: 01/23/2023] Open
Abstract
Rice black streaked dwarf virus (RBSDV) is an important agent causing maize rough dwarf disease, whereas the host factors responding to RBSDV infection are poorly understood. To uncover the molecular interactions between RBSDV and maize, a yeast two-hybrid screen of a maize cDNA library was carried out using the viral P8 protein as a bait. ZmAKINβγ-1 and ZmAKINβγ-2 (βγ subunit of Arabidopsis SNF1 kinase homolog in maize) possessing high sequence similarities (encoded by two gene copies) were identified as interaction partners. Their interactions with P8 were confirmed in both Nicotiana benthamiana cells and maize protoplasts by bimolecular fluorescence complementation assay. The accumulation levels of ZmAKINβγ mRNAs were upregulated at the stage of the viral symptoms beginning to appear and then downregulated. ZmAKINβγs are putative regulatory subunits of the SnRK1 complex, a core regulator for energy homeostasis. Knockdown of ZmAKINβγs in maize regulated the expression levels of the genes involved in sugar synthesis or degradation, and also the contents of both glucose and sucrose. Importantly, downregulation of ZmAKINβγs expressions facilitated the accumulation of RBSDV in maize. These results implicate a role of ZmAKINβγs in the regulation of primary carbohydrate metabolism, and in the defense against RBSDV infection.
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Affiliation(s)
- Mingjun Li
- State Key Laboratory of Agro-Biotechnology and Key Laboratory of Pest Monitoring and Green Management-MOA, China Agricultural University, Beijing 100193, China; (X.S.); (T.Z.)
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing 400716, China;
- Correspondence: (M.L.); (Z.F.); Tel.: +86-10-62732771 (Z.F.)
| | - Xi Sun
- State Key Laboratory of Agro-Biotechnology and Key Laboratory of Pest Monitoring and Green Management-MOA, China Agricultural University, Beijing 100193, China; (X.S.); (T.Z.)
| | - Dianping Di
- Plant Protection Institute, Hebei Academy of Agricultural and Forestry Sciences, Baoding 071000, China; (D.D.); (A.Z.); (H.M.)
| | - Aihong Zhang
- Plant Protection Institute, Hebei Academy of Agricultural and Forestry Sciences, Baoding 071000, China; (D.D.); (A.Z.); (H.M.)
| | - Ling Qing
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing 400716, China;
| | - Tao Zhou
- State Key Laboratory of Agro-Biotechnology and Key Laboratory of Pest Monitoring and Green Management-MOA, China Agricultural University, Beijing 100193, China; (X.S.); (T.Z.)
| | - Hongqin Miao
- Plant Protection Institute, Hebei Academy of Agricultural and Forestry Sciences, Baoding 071000, China; (D.D.); (A.Z.); (H.M.)
| | - Zaifeng Fan
- State Key Laboratory of Agro-Biotechnology and Key Laboratory of Pest Monitoring and Green Management-MOA, China Agricultural University, Beijing 100193, China; (X.S.); (T.Z.)
- Correspondence: (M.L.); (Z.F.); Tel.: +86-10-62732771 (Z.F.)
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Galic V, Mazur M, Brkic A, Brkic J, Jambrovic A, Zdunic Z, Simic D. Seed Weight as a Covariate in Association and Prediction Studies for Biomass Traits in Maize Seedlings. PLANTS (BASEL, SWITZERLAND) 2020; 9:E275. [PMID: 32093233 PMCID: PMC7076456 DOI: 10.3390/plants9020275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND The seedling stage has received little attention in maize breeding to identify genotypes tolerant to water deficit. The aim of this study is to evaluate incorporation of seed weight (expressed as hundred kernel weight, HKW) as a covariate into genomic association and prediction studies for three biomass traits in a panel of elite inbred lines challenged by water withholding at seedling stage. METHODS 109 genotyped-by-sequencing (GBS) elite maize inbreds were phenotyped for HKW and planted in controlled conditions (16/8 day/night, 25 °C, 50% RH, 200 µMol/m2/s) in trays filled with soil. Plants in control (C) were watered every two days, while watering was stopped for 10 days in water withholding (WW). Fresh weight (FW), dry weight (DW), and dry matter content (DMC) were measured. RESULTS Adding HKW as a covariate increased the power of detection of associations in FW and DW by 44% and increased genomic prediction accuracy in C and decreased in WW. CONCLUSIONS Seed weight was effectively incorporated into association studies for biomass traits in maize seedlings, whereas the incorporation into genomic predictions, particularly in water-stressed plants, was not worthwhile.
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Affiliation(s)
- Vlatko Galic
- Department of Maize Breeding and Genetics, Agricultural Institute Osijek, Južno predgrađe 17, HR31000 Osijek, Croatia
| | - Maja Mazur
- Department of Maize Breeding and Genetics, Agricultural Institute Osijek, Južno predgrađe 17, HR31000 Osijek, Croatia
| | - Andrija Brkic
- Department of Maize Breeding and Genetics, Agricultural Institute Osijek, Južno predgrađe 17, HR31000 Osijek, Croatia
| | - Josip Brkic
- Department of Maize Breeding and Genetics, Agricultural Institute Osijek, Južno predgrađe 17, HR31000 Osijek, Croatia
| | - Antun Jambrovic
- Department of Maize Breeding and Genetics, Agricultural Institute Osijek, Južno predgrađe 17, HR31000 Osijek, Croatia
- Centre of Excellence for Biodiversity and Molecular Plant Breeding (CroP-BioDiv), Svetošimunska cesta 25, HR10000 Zagreb, Croatia
| | - Zvonimir Zdunic
- Department of Maize Breeding and Genetics, Agricultural Institute Osijek, Južno predgrađe 17, HR31000 Osijek, Croatia
- Centre of Excellence for Biodiversity and Molecular Plant Breeding (CroP-BioDiv), Svetošimunska cesta 25, HR10000 Zagreb, Croatia
| | - Domagoj Simic
- Department of Maize Breeding and Genetics, Agricultural Institute Osijek, Južno predgrađe 17, HR31000 Osijek, Croatia
- Centre of Excellence for Biodiversity and Molecular Plant Breeding (CroP-BioDiv), Svetošimunska cesta 25, HR10000 Zagreb, Croatia
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Jamsheer K M, Jindal S, Laxmi A. Evolution of TOR-SnRK dynamics in green plants and its integration with phytohormone signaling networks. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2239-2259. [PMID: 30870564 DOI: 10.1093/jxb/erz107] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 02/26/2019] [Indexed: 05/07/2023]
Abstract
The target of rapamycin (TOR)-sucrose non-fermenting 1 (SNF1)-related protein kinase 1 (SnRK1) signaling is an ancient regulatory mechanism that originated in eukaryotes to regulate nutrient-dependent growth. Although the TOR-SnRK1 signaling cascade shows highly conserved functions among eukaryotes, studies in the past two decades have identified many important plant-specific innovations in this pathway. Plants also possess SnRK2 and SnRK3 kinases, which originated from the ancient SnRK1-related kinases and have specialized roles in controlling growth, stress responses and nutrient homeostasis in plants. Recently, an integrative picture has started to emerge in which different SnRKs and TOR kinase are highly interconnected to control nutrient and stress responses of plants. Further, these kinases are intimately involved with phytohormone signaling networks that originated at different stages of plant evolution. In this review, we highlight the evolution and divergence of TOR-SnRK signaling components in plants and their communication with each other as well as phytohormone signaling to fine-tune growth and stress responses in plants.
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Affiliation(s)
- Muhammed Jamsheer K
- Amity Food & Agriculture Foundation, Amity University Uttar Pradesh, Noida, India
| | - Sunita Jindal
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Ashverya Laxmi
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
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Blanco NE, Liebsch D, Guinea Díaz M, Strand Å, Whelan J. Dual and dynamic intracellular localization of Arabidopsis thaliana SnRK1.1. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2325-2338. [PMID: 30753728 DOI: 10.1093/jxb/erz023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 02/01/2019] [Indexed: 06/09/2023]
Abstract
Sucrose non-fermenting 1 (SNF1)-related protein kinase 1.1 (SnRK1.1; also known as KIN10 or SnRK1α) has been identified as the catalytic subunit of the complex SnRK1, the Arabidopsis thaliana homologue of a central integrator of energy and stress signalling in eukaryotes dubbed AMPK/Snf1/SnRK1. A nuclear localization of SnRK1.1 has been previously described and is in line with its function as an integrator of energy and stress signals. Here, using two biological models (Nicotiana benthamiana and Arabidopsis thaliana), native regulatory sequences, different microscopy techniques, and manipulations of cellular energy status, it was found that SnRK1.1 is localized dynamically between the nucleus and endoplasmic reticulum (ER). This distribution was confirmed at a spatial and temporal level by co-localization studies with two different fluorescent ER markers, one of them being the SnRK1.1 phosphorylation target HMGR. The ER and nuclear localization displayed a dynamic behaviour in response to perturbations of the plastidic electron transport chain. These results suggest that an ER-associated SnRK1.1 fraction might be sensing the cellular energy status, being a point of crosstalk with other ER stress regulatory pathways.
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Affiliation(s)
- Nicolás E Blanco
- Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario (CEFOBI-CONICET/UNR), Rosario, Argentina
- Umeå Plant Science Centre, Department of Plant Physiologyogy, Umeå University, Sweden
| | - Daniela Liebsch
- Umeå Plant Science Centre, Department of Plant Physiologyogy, Umeå University, Sweden
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Rosario, Argentina
| | - Manuel Guinea Díaz
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
| | - Åsa Strand
- Umeå Plant Science Centre, Department of Plant Physiologyogy, Umeå University, Sweden
| | - James Whelan
- Department of Animal, Plant and Soil Science, School of Life Sciences, Australian Research Council Centre of Excellence in Plant Energy Biology, La Trobe University, Bundoora, Victoria, Australia
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Identification of multiple genes encoding SnRK1 subunits in potato tuber. PLoS One 2018; 13:e0200321. [PMID: 29979765 PMCID: PMC6034879 DOI: 10.1371/journal.pone.0200321] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 06/23/2018] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Many studies have proven the importance of SnRK1 in the regulation of carbohydrate metabolism and plant development. Compared to Arabidopsis, much less is known about SnRK1 complexes in crop plants, and therefore, more work needs to be done to identify SnRK1 genes and to investigate their function in crop plants. METHODS In this study we identified five SnRK1-related genes in potato by analyzing the potato genome through BLAST, which encode one α-subunit isoform (stKIN), two β-subunit isoforms (stKINβ1 and stKINβ2) and two γ-subunit isoforms (stKINγ and stKINβγ). To investigate the functions of SnRK1 in the tuber development of potato, we further made overexpression and RNAi transgenic plants of these five genes. Based on these overexpression transgenic plants, the Fast protein liquid chromatography (FPLC) were employed to purify SnRK1 complexes, which were tracked by western-blot. RESULTS Experiments in vivo and in vitro showed that these five proteins in potato are functional SNF1/AMPK/SnRK1-related proteins. The SnRK1 activity decreased by 60% in the RNAi transgenic lines of stKIN; the starch content increased by 25% in the overexpression transgenic lines of stKIN, compared to that in the wild-type lines, whereas there is no significant difference in SnRK1 activity and starch content in the RNAi transgenic or overexpression lines of stKINβ1, stKINβ2, stKINγ and stKINβγ. In addition, we found that a few different SnRK1 complexes are present in potato by partially purifying SnRK1 complexes from these overexpression transgenic plants. CONCLUSIONS Five functional SnRK1-related genes were identified in potato, including three novel genes, which encode one α-subunit isoform (stKIN), two β-subunit isoforms (stKINβ1 and stKINβ2) and two γ-subunit isoforms (stKINγ and stKINβγ). We found that a few SnRK1 related genes are present in potato tuber, which form several different SnRK1 isoenzymes. We found that stKIN is the primary α subunit of SnRK1 in potato tuber and plays important roles in the development of potato tubers.
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Broeckx T, Hulsmans S, Rolland F. The plant energy sensor: evolutionary conservation and divergence of SnRK1 structure, regulation, and function. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:6215-6252. [PMID: 27856705 DOI: 10.1093/jxb/erw416] [Citation(s) in RCA: 151] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The SnRK1 (SNF1-related kinase 1) kinases are the plant cellular fuel gauges, activated in response to energy-depleting stress conditions to maintain energy homeostasis while also gatekeeping important developmental transitions for optimal growth and survival. Similar to their opisthokont counterparts (animal AMP-activated kinase, AMPK, and yeast Sucrose Non-Fermenting 1, SNF), they function as heterotrimeric complexes with a catalytic (kinase) α subunit and regulatory β and γ subunits. Although the overall configuration of the kinase complexes is well conserved, plant-specific structural modifications (including a unique hybrid βγ subunit) and associated differences in regulation reflect evolutionary divergence in response to fundamentally different lifestyles. While AMP is the key metabolic signal activating AMPK in animals, the plant kinases appear to be allosterically inhibited by sugar-phosphates. Their function is further fine-tuned by differential subunit expression, localization, and diverse post-translational modifications. The SnRK1 kinases act by direct phosphorylation of key metabolic enzymes and regulatory proteins, extensive transcriptional regulation (e.g. through bZIP transcription factors), and down-regulation of TOR (target of rapamycin) kinase signaling. Significant progress has been made in recent years. New tools and more directed approaches will help answer important fundamental questions regarding their structure, regulation, and function, as well as explore their potential as targets for selection and modification for improved plant performance in a changing environment.
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Affiliation(s)
- Tom Broeckx
- Laboratory for Molecular Plant Biology, Biology Department, University of Leuven-KU Leuven, Kasteelpark Arenberg 31, 3001 Heverlee-Leuven, Belgium
| | - Sander Hulsmans
- Laboratory for Molecular Plant Biology, Biology Department, University of Leuven-KU Leuven, Kasteelpark Arenberg 31, 3001 Heverlee-Leuven, Belgium
| | - Filip Rolland
- Laboratory for Molecular Plant Biology, Biology Department, University of Leuven-KU Leuven, Kasteelpark Arenberg 31, 3001 Heverlee-Leuven, Belgium
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Gao XQ, Liu CZ, Li DD, Zhao TT, Li F, Jia XN, Zhao XY, Zhang XS. The Arabidopsis KINβγ Subunit of the SnRK1 Complex Regulates Pollen Hydration on the Stigma by Mediating the Level of Reactive Oxygen Species in Pollen. PLoS Genet 2016; 12:e1006228. [PMID: 27472382 PMCID: PMC4966946 DOI: 10.1371/journal.pgen.1006228] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 07/08/2016] [Indexed: 12/25/2022] Open
Abstract
Pollen–stigma interactions are essential for pollen germination. The highly regulated process of pollen germination includes pollen adhesion, hydration, and germination on the stigma. However, the internal signaling of pollen that regulates pollen–stigma interactions is poorly understood. KINβγ is a plant-specific subunit of the SNF1-related protein kinase 1 complex which plays important roles in the regulation of plant development. Here, we showed that KINβγ was a cytoplasm- and nucleus-localized protein in the vegetative cells of pollen grains in Arabidopsis. The pollen of the Arabidopsis kinβγ mutant could not germinate on stigma, although it germinated normally in vitro. Further analysis revealed the hydration of kinβγ mutant pollen on the stigma was compromised. However, adding water to the stigma promoted the germination of the mutant pollen in vivo, suggesting that the compromised hydration of the mutant pollen led to its defective germination. In kinβγ mutant pollen, the structure of the mitochondria and peroxisomes was destroyed, and their numbers were significantly reduced compared with those in the wild type. Furthermore, we found that the kinβγ mutant exhibited reduced levels of reactive oxygen species (ROS) in pollen. The addition of H2O2in vitro partially compensated for the reduced water absorption of the mutant pollen, and reducing ROS levels in pollen by overexpressing Arabidopsis CATALASE 3 resulted in compromised hydration of pollen on the stigma. These results indicate that Arabidopsis KINβγ is critical for the regulation of ROS levels by mediating the biogenesis of mitochondria and peroxisomes in pollen, which is required for pollen–stigma interactions during pollination. After landing on the stigma, pollen grains germinate and create pollen tubes following adhesion and hydration processes, during which pollen–stigma interactions determine whether the pollen grains can germinate on the stigma. In recent years, the interaction mechanisms between the pollen and stigma have been studied extensively at the cellular and molecular level in self-incompatibility systems. However, few studies have focused on pollen–stigma interactions during self-compatible pollination. Arabidopsis thaliana provides an excellent system to study the interaction mechanisms between the pollen and stigma during self-compatible pollination. KINβγ is a plant-specific subunit of the SNF1-related protein kinase 1 complex. In this study, we identified an Arabidopsis kinβγ mutant showing defective pollen germination on the surface of the stigma but not on the culture medium, which resulted from the compromised hydration of pollen on the stigma. Further analysis revealed that the biogenesis of mitochondria and peroxisomes was impaired in this mutant, which reduced the levels of reactive oxygen species (ROS) in pollen. Application of H2O2 recovered the capability of pollen to undergo hydration in vitro. These results suggest that ROS signaling is involved in the regulation of pollen–stigma interactions during pollination. This study provides new insights into the mechanism underlying pollen–stigma interactions in self-compatible plant species.
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Affiliation(s)
- Xin-Qi Gao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Chang Zhen Liu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Dan Dan Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Ting Ting Zhao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Fei Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Xiao Na Jia
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Xin-Ying Zhao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Xian Sheng Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
- * E-mail:
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Emanuelle S, Doblin MS, Stapleton DI, Bacic A, Gooley PR. Molecular Insights into the Enigmatic Metabolic Regulator, SnRK1. TRENDS IN PLANT SCIENCE 2016; 21:341-353. [PMID: 26642889 DOI: 10.1016/j.tplants.2015.11.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 10/13/2015] [Accepted: 11/03/2015] [Indexed: 05/20/2023]
Abstract
Sucrose non-fermenting-1 (SNF1)-related kinase 1 (SnRK1) lies at the heart of metabolic homeostasis in plants and is crucial for normal development and response to stress. Evolutionarily related to SNF1 in yeast and AMP-activated kinase (AMPK) in mammals, SnRK1 acts protectively to maintain homeostasis in the face of fluctuations in energy status. Despite a conserved function, the structure and regulation of the plant kinase differ considerably from its relatively well-understood opisthokont orthologues. In this review, we highlight the known plant-specific modes of regulation involving SnRK1 together with new insights based on a 3D molecular model of the kinase. We also summarise how these differences from other orthologues may be specific adaptations to plant metabolism, and offer insights into possible avenues of future inquiry into this enigmatic enzyme.
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Affiliation(s)
- Shane Emanuelle
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Monika S Doblin
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - David I Stapleton
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Antony Bacic
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia.
| | - Paul R Gooley
- Department of Biochemistry & Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC 3010, Australia
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Plant SnRK1 Kinases: Structure, Regulation, and Function. EXPERIENTIA SUPPLEMENTUM 2016; 107:403-438. [DOI: 10.1007/978-3-319-43589-3_17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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O'Brien M, Kaplan-Levy RN, Quon T, Sappl PG, Smyth DR. PETAL LOSS, a trihelix transcription factor that represses growth in Arabidopsis thaliana, binds the energy-sensing SnRK1 kinase AKIN10. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:2475-85. [PMID: 25697797 PMCID: PMC4986862 DOI: 10.1093/jxb/erv032] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Organogenesis in plants involves differential growth. Rapidly growing primordia are distinguished from the meristem and each other by slower growing boundaries. PETAL LOSS (PTL) is a trihelix transcription factor of Arabidopsis that represses growth in boundaries between newly arising sepals. To identify partners involved in this growth limitation, a young inflorescence cDNA library was screened by yeast two-hybrid technology with PTL as bait. The most frequent prey identified was AKIN10, the catalytic α-subunit of the Snf1-related kinase1 (SnRK1). Interaction was mapped to the C-terminal (non-kinase) half of AKIN10 and the N-terminal portion of PTL. Binding of PTL was specific to AKIN10 as there was little binding to the related AKIN11. The interaction was confirmed by co-immunoprecipitation in vitro. Fluorescently tagged products of 35S:YFP-AKIN10 and 35S:CFP-PTL also interacted when transiently expressed together in leaf cells of Nicotiana benthamiana. In this case, most of the cytoplasmic AKIN10 was preferentially moved to the nucleus where PTL accumulated, possibly because a nuclear export sequence in AKIN10 was now masked. During these experiments, we observed that AKIN10 could variably accumulate in the Golgi, shown by its co-localization with a tagged Golgi marker and through its dispersal by brefeldin A. Tests of phosphorylation of PTL by AKIN10 gave negative results. The functional significance of the PTL-AKIN10 interaction remains open, although a testable hypothesis is that AKIN10 senses lower energy levels in inter-sepal zones and, in association with PTL, promotes reduced cell division.
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Affiliation(s)
- Martin O'Brien
- School of Biological Sciences, Monash University, Melbourne, Vic. 3800, Australia
| | - Ruth N Kaplan-Levy
- School of Biological Sciences, Monash University, Melbourne, Vic. 3800, Australia
| | - Tezz Quon
- School of Biological Sciences, Monash University, Melbourne, Vic. 3800, Australia
| | - Pia G Sappl
- School of Biological Sciences, Monash University, Melbourne, Vic. 3800, Australia
| | - David R Smyth
- School of Biological Sciences, Monash University, Melbourne, Vic. 3800, Australia
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Emanuelle S, Hossain MI, Moller IE, Pedersen HL, van de Meene AML, Doblin MS, Koay A, Oakhill JS, Scott JW, Willats WGT, Kemp BE, Bacic A, Gooley PR, Stapleton DI. SnRK1 from Arabidopsis thaliana is an atypical AMPK. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:183-92. [PMID: 25736509 DOI: 10.1111/tpj.12813] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 02/17/2015] [Accepted: 02/23/2015] [Indexed: 05/05/2023]
Abstract
SNF1-related protein kinase 1 (SnRK1) is the plant orthologue of the evolutionarily-conserved SNF1/AMPK/SnRK1 protein kinase family that contributes to cellular energy homeostasis. Functional as heterotrimers, family members comprise a catalytic α subunit and non-catalytic β and γ subunits; multiple isoforms of each subunit type exist, giving rise to various isoenzymes. The Arabidopsis thaliana genome contains homologues of each subunit type, and, in addition, two atypical subunits, β(3) and βγ, with unique domain architecture, that are found only amongst plants, suggesting atypical heterotrimers. The AtSnRK1 subunit structure was determined using recombinant protein expression and endogenous co-immunoprecipitation, and six unique isoenzyme combinations were identified. Each heterotrimeric isoenzyme comprises a catalytic α subunit together with the unique βγ subunit and one of three non-catalytic β subunits: β(1), β(2) or the plant-specific β(3) isoform. Thus, the AtSnRK1 heterotrimers contain the atypical βγ subunit rather than a conventional γ subunit. Mammalian AMPK heterotrimers are phosphorylated on the T-loop (pThr175/176) within both catalytic a subunits. However, AtSnRK1 is insensitive to AMP and ADP, and is resistant to T-loop dephosphorylation by protein phosphatases, a process that inactivates other SNF1/AMPK family members. In addition, we show that SnRK1 is inhibited by a heat-labile, >30 kDa, soluble proteinaceous factor that is present in the lysate of young rosette leaves. Finally, none of the three SnRK1 carbohydrate-binding modules, located in the β(1), β(2) and βγ subunits, associate with various carbohydrates, including starch, the plant analogue of glycogen to which AMPK binds in vitro. These data clearly demonstrate that AtSnRK1 is an atypical member of the SNF1/AMPK/SnRK1 family.
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Affiliation(s)
- Shane Emanuelle
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of Botany, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, 3010, Australia; Department of Biochemistry & Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, 3010, Australia
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Ávila-Castañeda A, Gutiérrez-Granados N, Ruiz-Gayosso A, Sosa-Peinado A, Martínez-Barajas E, Coello P. Structural and functional basis for starch binding in the SnRK1 subunits AKINβ2 and AKINβγ. FRONTIERS IN PLANT SCIENCE 2014; 5:199. [PMID: 24904601 PMCID: PMC4032982 DOI: 10.3389/fpls.2014.00199] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 04/24/2014] [Indexed: 05/20/2023]
Abstract
Specialized carbohydrate-binding domains, the Starch-Binding Domain (SBD) and the Glycogen Binding Domain (GBD), are motifs of approximately 100 amino acids directly or indirectly associated with starch or glycogen metabolism. Members of the regulatory β subunit of the heterotrimeric complex AMPK/SNF1/SnRK1 contain an SBD or GBD. In Arabidopsis thaliana, the β regulatory subunit AKINβ2 and a γ-type subunit, AKINβγ, also have an SBD. In this work, we compared the SBD of AKINβ2 and AKINβγ with the GBD present in rat AMPKβ1 and demonstrated that they conserved the same overall topology. The majority of the amino acids identified in the protein-carbohydrate interactions in the rat AMPKβ1 are conserved in the two plant proteins. In AKINβγ, there is an insertion of three amino acids that creates a loop adjacent to one of the conserved tryptophan residues. Functionally, the SBD from AKINβγ and AKINβ2 could bind starch, but there was an important difference in the association when an amylose/amylopectin (A/A) mixture was used. The physiological relevance of binding to starch was clear for AKINβγ, because immunolocalization experiments identified this protein inside the chloroplast. SnRK1 activity was not affected by the addition of A/A to the reaction mixture. However, addition of starch inhibited the activity 85%. Furthermore, proteins associated with A/A and starch in an in vitro-binding assay accounted for 10-20% of total SnRK1 kinase activity. Interestingly, the identification of the SnRK1 subunits associated to the protein-carbohydrate complex indicated that only the catalytic subunits, AKIN10 and AKIN11, and the regulatory subunit AKINβγ were present. These results suggest that a dimer formed between either catalytic subunit and AKINβγ could be associated with the A/A mixture in its active form but the same subunits are inactivated when binding to starch.
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Affiliation(s)
- Alejandra Ávila-Castañeda
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de MéxicoMéxico City, México
| | - Natalia Gutiérrez-Granados
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de MéxicoMéxico City, México
| | - Ana Ruiz-Gayosso
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de MéxicoMéxico City, México
| | - Alejandro Sosa-Peinado
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de MéxicoMéxico City, México
| | - Eleazar Martínez-Barajas
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de MéxicoMéxico City, México
| | - Patricia Coello
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de MéxicoMéxico City, México
- *Correspondence: Patricia Coello, Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, 04510 D.F., México e-mail:
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Williams SP, Rangarajan P, Donahue JL, Hess JE, Gillaspy GE. Regulation of Sucrose non-Fermenting Related Kinase 1 genes in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2014; 5:324. [PMID: 25071807 PMCID: PMC4090914 DOI: 10.3389/fpls.2014.00324] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 06/21/2014] [Indexed: 05/05/2023]
Abstract
The Sucrose non-Fermenting Related Kinase 1 (SnRK1) proteins have been linked to regulation of energy and stress signaling in eukaryotes. In plants, there is a small SnRK1 gene family. While the SnRK1.1 gene has been well studied, the role other SnRK1 isoforms play in energy or stress signaling is less well understood. We used promoter:GUS analysis and found SnRK1.1 is broadly expressed, while SnRK1.2 is spatially restricted. SnRK1.2 is expressed most abundantly in hydathodes, at the base of leaf primordia, and in vascular tissues within both shoots and roots. We examined the impact that sugars have on SnRK1 gene expression and found that trehalose induces SnRK1.2 expression. Given that the SnRK1.1 and SnRK1.2 proteins are very similar at the amino acid level, we sought to address whether SnRK1.2 is capable of re-programming growth and development as has been seen previously with SnRK1.1 overexpression. While gain-of-function transgenic plants overexpressing two different isoforms of SnRK1.1 flower late as seen previously in other SnRK1.1 overexpressors, SnRK1.2 overexpressors flower early. In addition, SnRK1.2 overexpressors have increased leaf size and rosette diameter during early development, which is the opposite of SnRK1.1 overexpressors. We also investigated whether SnRK1.2 was localized to similar subcellular compartments as SnRK1.1, and found that both accumulate in the nucleus and cytoplasm in transient expression assays. In addition, we found SnRK1.1 accumulates in small puncta that appear after a mechanical wounding stress. Together, these data suggest key differences in regulation of the SnRK1.1 and SnRK1.2 genes in plants, and highlights differences overexpression of each gene has on the development of Arabidopsis.
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Affiliation(s)
| | | | | | | | - Glenda E. Gillaspy
- Department of Biochemistry, Virginia TechBlacksburg, VA, USA
- *Correspondence: Glenda E. Gillaspy, Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA e-mail:
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14
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Crozet P, Margalha L, Confraria A, Rodrigues A, Martinho C, Adamo M, Elias CA, Baena-González E. Mechanisms of regulation of SNF1/AMPK/SnRK1 protein kinases. FRONTIERS IN PLANT SCIENCE 2014; 5:190. [PMID: 24904600 PMCID: PMC4033248 DOI: 10.3389/fpls.2014.00190] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/22/2014] [Indexed: 05/17/2023]
Abstract
The SNF1 (sucrose non-fermenting 1)-related protein kinases 1 (SnRKs1) are the plant orthologs of the budding yeast SNF1 and mammalian AMPK (AMP-activated protein kinase). These evolutionarily conserved kinases are metabolic sensors that undergo activation in response to declining energy levels. Upon activation, SNF1/AMPK/SnRK1 kinases trigger a vast transcriptional and metabolic reprograming that restores energy homeostasis and promotes tolerance to adverse conditions, partly through an induction of catabolic processes and a general repression of anabolism. These kinases typically function as a heterotrimeric complex composed of two regulatory subunits, β and γ, and an α-catalytic subunit, which requires phosphorylation of a conserved activation loop residue for activity. Additionally, SNF1/AMPK/SnRK1 kinases are controlled by multiple mechanisms that have an impact on kinase activity, stability, and/or subcellular localization. Here we will review current knowledge on the regulation of SNF1/AMPK/SnRK1 by upstream components, post-translational modifications, various metabolites, hormones, and others, in an attempt to highlight both the commonalities of these essential eukaryotic kinases and the divergences that have evolved to cope with the particularities of each one of these systems.
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Affiliation(s)
| | | | | | - Américo Rodrigues
- Instituto Gulbenkian de CiênciaOeiras, Portugal
- Escola Superior de Turismo e Tecnologia do Mar de Peniche, Instituto Politécnico de LeiriaPeniche, Portugal
| | | | | | | | - Elena Baena-González
- Instituto Gulbenkian de CiênciaOeiras, Portugal
- *Correspondence: Elena Baena-González, Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal e-mail:
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Ramon M, Ruelens P, Li Y, Sheen J, Geuten K, Rolland F. The hybrid four-CBS-domain KINβγ subunit functions as the canonical γ subunit of the plant energy sensor SnRK1. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 75:11-25. [PMID: 23551663 PMCID: PMC6599549 DOI: 10.1111/tpj.12192] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 03/15/2013] [Accepted: 03/26/2013] [Indexed: 05/17/2023]
Abstract
The AMPK/SNF1/SnRK1 protein kinases are a family of ancient and highly conserved eukaryotic energy sensors that function as heterotrimeric complexes. These typically comprise catalytic α subunits and regulatory β and γ subunits, the latter function as the energy-sensing modules of animal AMPK through adenosine nucleotide binding. The ability to monitor accurately and adapt to changing environmental conditions and energy supply is essential for optimal plant growth and survival, but mechanistic insight in the plant SnRK1 function is still limited. In addition to a family of γ-like proteins, plants also encode a hybrid βγ protein that combines the Four-Cystathionine β-synthase (CBS)-domain (FCD) structure in γ subunits with a glycogen-binding domain (GBD), typically found in β subunits. We used integrated functional analyses by ectopic SnRK1 complex reconstitution, yeast mutant complementation, in-depth phylogenetic reconstruction, and a seedling starvation assay to show that only the hybrid KINβγ protein that recruited the GBD around the emergence of the green chloroplast-containing plants, acts as the canonical γ subunit required for heterotrimeric complex formation. Mutagenesis and truncation analysis further show that complex interaction in plant cells and γ subunit function in yeast depend on both a highly conserved FCD and a pre-CBS domain, but not the GBD. In addition to novel insight into canonical AMPK/SNF/SnRK1 γ subunit function, regulation and evolution, we provide a new classification of plant FCD genes as a convenient and reliable tool to predict regulatory partners for the SnRK1 energy sensor and novel FCD gene functions.
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Affiliation(s)
- Matthew Ramon
- Laboratory of Molecular Plant Biology, KU Leuven Department of Biology, B-3001, Leuven, Belgium
| | - Philip Ruelens
- Laboratory of Molecular Plant Biology, KU Leuven Department of Biology, B-3001, Leuven, Belgium
| | - Yi Li
- Laboratory of Molecular Plant Biology, KU Leuven Department of Biology, B-3001, Leuven, Belgium
| | - Jen Sheen
- Department of Molecular Biology and Center for Computational and Integrative, Biology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Koen Geuten
- Laboratory of Molecular Plant Biology, KU Leuven Department of Biology, B-3001, Leuven, Belgium
| | - Filip Rolland
- Laboratory of Molecular Plant Biology, KU Leuven Department of Biology, B-3001, Leuven, Belgium
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Tsai AYL, Gazzarrini S. AKIN10 and FUSCA3 interact to control lateral organ development and phase transitions in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 69:809-21. [PMID: 22026387 DOI: 10.1111/j.1365-313x.2011.04832.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The Snf1 (sucrose non-fermenting-1)/AMPK (AMP-activated protein kinase)/SnRK1 (Snf1-related protein kinase 1) kinases act as sensors of energy status in eukaryotes. Despite the important role of these kinases in regulation of cellular responses to metabolic stress, only a few SnRK1 substrates have been identified. Using yeast two-hybrid screens, we isolated AKIN10 as an interactor of the B3-domain transcription factor FUSCA3 (FUS3), an essential regulator of seed maturation in Arabidopsis. Pull-down and bi-molecular fluorescence complementation (BiFC) assays confirm the interaction in vitro and in planta, respectively. In-gel kinase assays show that AKIN10 phosphorylates FUS3 and that the N-terminal domain of FUS3 is required for AKIN10 phosphorylation. Mutations of three serines (fus3(S55A/S56A/S57A) ) within a partial SnRK1 consensus sequence in the N-terminal region of FUS3 reduce greatly FUS3 phosphorylation by AKIN10, which indicates that these serines are the predominant AKIN10 target sites. In a cell-free system, AKIN10 positively regulates FUS3 stability, as overexpression of AKIN10 delayed the degradation of the recombinant FUS3. Plants over-expressing AKIN10 show delayed seed germination, vegetative growth and flowering time, indicating that AKIN10 antagonizes the embryonic-to-vegetative and vegetative-to-reproductive phase transitions. Furthermore, overexpression of AKIN10 alters cotyledon, silique and floral organ development, suggesting that AKIN10 regulates lateral organ development. Genetic interaction studies show that the fus3-3 mutation partially rescues the phase transition and organ development defects caused by AKIN10 overexpression. Taken together, these findings indicate that FUS3 and AKIN10 interact physically and share overlapping pathways to regulate developmental phase transitions and organogenesis in Arabidopsis.
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Affiliation(s)
- Allen Yi-Lun Tsai
- Department of Biological Sciences and Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
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17
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Janeček Š, Svensson B, MacGregor EA. Structural and evolutionary aspects of two families of non-catalytic domains present in starch and glycogen binding proteins from microbes, plants and animals. Enzyme Microb Technol 2011; 49:429-40. [DOI: 10.1016/j.enzmictec.2011.07.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 07/04/2011] [Accepted: 07/06/2011] [Indexed: 10/18/2022]
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18
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Lumbreras V, Vilela B, Irar S, Solé M, Capellades M, Valls M, Coca M, Pagès M. MAPK phosphatase MKP2 mediates disease responses in Arabidopsis and functionally interacts with MPK3 and MPK6. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 63:1017-30. [PMID: 20626661 DOI: 10.1111/j.1365-313x.2010.04297.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Mitogen-activated protein kinase (MAPK) cascades have important functions in plant stress responses and development and are key players in reactive oxygen species (ROS) signalling and in innate immunity. In Arabidopsis, the transmission of ROS and pathogen signalling by MAPKs involves the coordinated activation of MPK6 and MPK3; however, the specificity of their negative regulation by phosphatases is not fully known. Here, we present genetic analyses showing that MAPK phosphatase 2 (MKP2) regulates oxidative stress and pathogen defence responses and functionally interacts with MPK3 and MPK6. We show that plants lacking a functional MKP2 gene exhibit delayed wilting symptoms in response to Ralstonia solanacearum and, by contrast, acceleration of disease progression during Botrytis cinerea infection, suggesting that this phosphatase plays differential functions in biotrophic versus necrotrophic pathogen-induced responses. MKP2 function appears to be linked to MPK3 and MPK6 regulation, as indicated by BiFC experiments showing that MKP2 associates with MPK3 and MPK6 in vivo and that in response to fungal elicitors MKP2 exerts differential affinity versus both kinases. We also found that MKP2 interacts with MPK6 in HR-like responses triggered by fungal elicitors, suggesting that MPK3 and MPK6 are subject to differential regulation by MKP2 in this process. We propose that MKP2 is a key regulator of MPK3 and MPK6 networks controlling both abiotic and specific pathogen responses in plants.
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Affiliation(s)
- Victoria Lumbreras
- Departamento de Genética Molecular, CRAG (CSIC-IRTA-UAB), 18-26 Jordi Girona, 08034 Barcelona, Spain.
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