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Blanford J, Zhai Z, Baer MD, Guo G, Liu H, Liu Q, Raugei S, Shanklin J. Molecular mechanism of trehalose 6-phosphate inhibition of the plant metabolic sensor kinase SnRK1. SCIENCE ADVANCES 2024; 10:eadn0895. [PMID: 38758793 PMCID: PMC11100557 DOI: 10.1126/sciadv.adn0895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 04/15/2024] [Indexed: 05/19/2024]
Abstract
SUCROSE-NON-FERMENTING1-RELATED PROTEIN KINASE1 (SnRK1), a central plant metabolic sensor kinase, phosphorylates its target proteins, triggering a global shift from anabolism to catabolism. Molecular modeling revealed that upon binding of KIN10 to GEMINIVIRUS REP-INTERACTING KINASE1 (GRIK1), KIN10's activation T-loop reorients into GRIK1's active site, enabling its phosphorylation and activation. Trehalose 6-phosphate (T6P) is a proxy for cellular sugar status and a potent inhibitor of SnRK1. T6P binds to KIN10, a SnRK1 catalytic subunit, weakening its affinity for GRIK1. Here, we investigate the molecular details of T6P inhibition of KIN10. Molecular dynamics simulations and in vitro phosphorylation assays identified and validated the T6P binding site on KIN10. Under high-sugar conditions, T6P binds to KIN10, blocking the reorientation of its activation loop and preventing its phosphorylation and activation by GRIK1. Under these conditions, SnRK1 maintains only basal activity levels, minimizing phosphorylation of its target proteins, thereby facilitating a general shift from catabolism to anabolism.
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Affiliation(s)
- Jantana Blanford
- Department of Biology, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Zhiyang Zhai
- Department of Biology, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Marcel D. Baer
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Gongrui Guo
- Department of Biology, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Hui Liu
- Department of Biology, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Qun Liu
- Department of Biology, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Simone Raugei
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - John Shanklin
- Department of Biology, Brookhaven National Laboratory, Upton, NY 11973, USA
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Sun J, Liu H, Blanford JK, Cai Y, Zhai Z, Shanklin J. GRIK phosphorylates and activates KIN10 which also promotes its degradation. FRONTIERS IN PLANT SCIENCE 2024; 15:1375471. [PMID: 38590740 PMCID: PMC10999582 DOI: 10.3389/fpls.2024.1375471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 03/11/2024] [Indexed: 04/10/2024]
Abstract
The sensor kinase Sucrose Non-fermenting-1-Related Kinase 1 (SnRK1) plays a central role in energy and metabolic homeostasis. KIN10 is a major catalytic (α) kinase subunit of SnRK1 regulated by transcription, posttranslational modification, targeted protein degradation, and its subcellular localization. Geminivirus Rep Interacting Kinase 1 and 2 (GRIK1 and 2) are immediate upstream kinases of KIN10. In the transient protein expression assays carried out in Nicotiana benthamiana (N. benthamiana) leaves, GRIK1 not only phosphorylates KIN10 but also simultaneously initiates its degradation. Posttranslational GRIK-mediated KIN10 degradation is dependent on both GRIK kinase activity and phosphorylation of the KIN10 T-loop. KIN10 proteins are significantly enriched in the grik1-1 grik2-1 double mutant, consistent with the transient assays in N. benthamiana. Interestingly. Among the enriched KIN10 proteins from grik1-1 grik2-1, is a longer isoform, putatively derived by alternative splicing which is barely detectable in wild-type plants. The reduced stability of KIN10 upon phosphorylation and activation by GRIK represents a mechanism that enables the KIN10 activity to be rapidly reduced when the levels of intracellular sugar/energy are restored to their set point, representing an important homeostatic control that prevents a metabolic overreaction to low-sugar conditions. Since GRIKs are activating kinases of KIN10, KIN10s in the grik1 grik2 double null mutant background remain un-phosphorylated, with only their basal level of activity, are more stable, and therefore increase in abundance, which also explains the longer isoform KIN10L which is a minor isoform in wild type is clearly detected in the grik1 grik2 double mutant.
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Kumar P, Madhawan A, Sharma A, Sharma V, Das D, Parveen A, Fandade V, Sharma D, Roy J. A sucrose non-fermenting-1-related protein kinase 1 gene from wheat, TaSnRK1α regulates starch biosynthesis by modulating AGPase activity. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 207:108407. [PMID: 38340690 DOI: 10.1016/j.plaphy.2024.108407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 01/27/2024] [Indexed: 02/12/2024]
Abstract
Major portion of wheat grain consist of carbohydrate, mainly starch. The proportion of amylose and amylopectin in starch greatly influence the end product quality. Advancement in understanding starch biosynthesis pathway and modulating key genes has enabled the genetic modification of crops resulting in enhanced starch quality. However, the regulation of starch biosynthesis genes still remains unexplored. So, to expand the limited knowledge, here, we characterized a Ser/Thr kinase, SnRK1α in wheat and determined its role in regulating starch biosynthesis. SnRK1 is an evolutionary conserved protein kinase and share homology to yeast SNF1. Yeast complementation assay suggests TaSnRK1α restores growth defect and promotes glycogen accumulation. Domain analysis and complementation assay with truncated domain proteins suggest the importance of ATP-binding and UBA domain in TaSnRK1α activity. Sub-cellular localization identified nuclear and cytoplasmic localization of TaSnRK1α in tobacco leaves. Further, heterologous over-expression (O/E) of TaSnRK1α in Arabidopsis not only led to increase in starch content but also enlarges the starch granules. TaSnRK1α was found to restore starch accumulation in Arabidopsis kin10. Remarkably, TaSnRK1α O/E increases the AGPase activity suggesting the direct regulation of rate limiting enzyme AGPase involved in starch biosynthesis. Furthermore, in vitro and in vivo interaction assay reveal that TaSnRK1α interacts with AGPase large sub-unit. Overall, our findings indicate that TaSnRK1α plays a role in starch biosynthesis by regulating AGPase activity.
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Affiliation(s)
- Prashant Kumar
- Agri-Food Biotechnology Division, National Agri-Food Biotechnology Institute, Mohali, 140306, Punjab, India; Regional Centre for Biotechnology (RCB), NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon 8 Expressway, Faridabad, Haryana, 121001, India.
| | - Akansha Madhawan
- Agri-Food Biotechnology Division, National Agri-Food Biotechnology Institute, Mohali, 140306, Punjab, India; Regional Centre for Biotechnology (RCB), NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon 8 Expressway, Faridabad, Haryana, 121001, India.
| | - Akshya Sharma
- Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India.
| | - Vinita Sharma
- Agri-Food Biotechnology Division, National Agri-Food Biotechnology Institute, Mohali, 140306, Punjab, India.
| | - Deepak Das
- Agri-Food Biotechnology Division, National Agri-Food Biotechnology Institute, Mohali, 140306, Punjab, India; Regional Centre for Biotechnology (RCB), NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon 8 Expressway, Faridabad, Haryana, 121001, India.
| | - Afsana Parveen
- Agri-Food Biotechnology Division, National Agri-Food Biotechnology Institute, Mohali, 140306, Punjab, India.
| | - Vikas Fandade
- Agri-Food Biotechnology Division, National Agri-Food Biotechnology Institute, Mohali, 140306, Punjab, India; Regional Centre for Biotechnology (RCB), NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon 8 Expressway, Faridabad, Haryana, 121001, India.
| | - Deepak Sharma
- Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India.
| | - Joy Roy
- Agri-Food Biotechnology Division, National Agri-Food Biotechnology Institute, Mohali, 140306, Punjab, India.
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Yang C, Li X, Yang L, Chen S, Liao J, Li K, Zhou J, Shen W, Zhuang X, Bai M, Bassham DC, Gao C. A positive feedback regulation of SnRK1 signaling by autophagy in plants. MOLECULAR PLANT 2023; 16:1192-1211. [PMID: 37408307 DOI: 10.1016/j.molp.2023.07.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 06/02/2023] [Accepted: 07/01/2023] [Indexed: 07/07/2023]
Abstract
SnRK1, an evolutionarily conserved heterotrimeric kinase complex that acts as a key metabolic sensor in maintaining energy homeostasis in plants, is an important upstream activator of autophagy that serves as a cellular degradation mechanism for the healthy growth of plants. However, whether and how the autophagy pathway is involved in regulating SnRK1 activity remains unknown. In this study, we identified a clade of plant-specific and mitochondria-localized FCS-like zinc finger (FLZ) proteins as currently unknown ATG8-interacting partners that actively inhibit SnRK1 signaling by repressing the T-loop phosphorylation of the catalytic α subunits of SnRK1, thereby negatively modulating autophagy and plant tolerance to energy deprivation caused by long-term carbon starvation. Interestingly, these AtFLZs are transcriptionally repressed by low-energy stress, and AtFLZ proteins undergo a selective autophagy-dependent pathway to be delivered to the vacuole for degradation, thereby constituting a positive feedback regulation to relieve their repression of SnRK1 signaling. Bioinformatic analyses show that the ATG8-FLZ-SnRK1 regulatory axis first appears in gymnosperms and seems to be highly conserved during the evolution of seed plants. Consistent with this, depletion of ATG8-interacting ZmFLZ14 confers enhanced tolerance, whereas overexpression of ZmFLZ14 leads to reduced tolerance to energy deprivation in maize. Collectively, our study reveals a previously unknown mechanism by which autophagy contributes to the positive feedback regulation of SnRK1 signaling, thereby enabling plants to better adapt to stressful environments.
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Affiliation(s)
- Chao Yang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, Ministry of Education & Guangdong Provincial Key Laboratory of Laser Life Science, School of Life Sciences, South China Normal University, Guangzhou 510631, China; Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Xibao Li
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, Ministry of Education & Guangdong Provincial Key Laboratory of Laser Life Science, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Lianming Yang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, Ministry of Education & Guangdong Provincial Key Laboratory of Laser Life Science, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Shunquan Chen
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, Ministry of Education & Guangdong Provincial Key Laboratory of Laser Life Science, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Jun Liao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, Ministry of Education & Guangdong Provincial Key Laboratory of Laser Life Science, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Kailin Li
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, Ministry of Education & Guangdong Provincial Key Laboratory of Laser Life Science, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Jun Zhou
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, Ministry of Education & Guangdong Provincial Key Laboratory of Laser Life Science, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Wenjin Shen
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, Ministry of Education & Guangdong Provincial Key Laboratory of Laser Life Science, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Xiaohong Zhuang
- Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Mingyi Bai
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Diane C Bassham
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Caiji Gao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, Ministry of Education & Guangdong Provincial Key Laboratory of Laser Life Science, School of Life Sciences, South China Normal University, Guangzhou 510631, China.
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Hung CY, Kittur FS, Wharton KN, Umstead ML, Burwell DB, Thomas M, Qi Q, Zhang J, Oldham CE, Burkey KO, Chen J, Xie J. A Rapid Alkalinization Factor-like Peptide EaF82 Impairs Tapetum Degeneration during Pollen Development through Induced ATP Deficiency. Cells 2023; 12:1542. [PMID: 37296662 PMCID: PMC10252199 DOI: 10.3390/cells12111542] [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: 04/24/2023] [Revised: 05/24/2023] [Accepted: 06/01/2023] [Indexed: 06/12/2023] Open
Abstract
In plants, the timely degeneration of tapetal cells is essential for providing nutrients and other substances to support pollen development. Rapid alkalinization factors (RALFs) are small, cysteine-rich peptides known to be involved in various aspects of plant development and growth, as well as defense against biotic and abiotic stresses. However, the functions of most of them remain unknown, while no RALF has been reported to involve tapetum degeneration. In this study, we demonstrated that a novel cysteine-rich peptide, EaF82, isolated from shy-flowering 'Golden Pothos' (Epipremnum aureum) plants, is a RALF-like peptide and displays alkalinizing activity. Its heterologous expression in Arabidopsis delayed tapetum degeneration and reduced pollen production and seed yields. RNAseq, RT-qPCR, and biochemical analyses showed that overexpression of EaF82 downregulated a group of genes involved in pH changes, cell wall modifications, tapetum degeneration, and pollen maturation, as well as seven endogenous Arabidopsis RALF genes, and decreased proteasome activity and ATP levels. Yeast two-hybrid screening identified AKIN10, a subunit of energy-sensing SnRK1 kinase, as its interacting partner. Our study reveals a possible regulatory role for RALF peptide in tapetum degeneration and suggests that EaF82 action may be mediated through AKIN10 leading to the alteration of transcriptome and energy metabolism, thereby causing ATP deficiency and impairing pollen development.
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Affiliation(s)
- Chiu-Yueh Hung
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA; (C.-Y.H.); (F.S.K.); (J.Z.); (C.E.O.)
| | - Farooqahmed S. Kittur
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA; (C.-Y.H.); (F.S.K.); (J.Z.); (C.E.O.)
| | - Keely N. Wharton
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA; (C.-Y.H.); (F.S.K.); (J.Z.); (C.E.O.)
| | - Makendra L. Umstead
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA; (C.-Y.H.); (F.S.K.); (J.Z.); (C.E.O.)
| | - D’Shawna B. Burwell
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA; (C.-Y.H.); (F.S.K.); (J.Z.); (C.E.O.)
| | - Martinique Thomas
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA; (C.-Y.H.); (F.S.K.); (J.Z.); (C.E.O.)
| | - Qi Qi
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA; (C.-Y.H.); (F.S.K.); (J.Z.); (C.E.O.)
| | - Jianhui Zhang
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA; (C.-Y.H.); (F.S.K.); (J.Z.); (C.E.O.)
| | - Carla E. Oldham
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA; (C.-Y.H.); (F.S.K.); (J.Z.); (C.E.O.)
| | - Kent O. Burkey
- USDA-ARS Plant Science Research Unit and Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC 27695, USA;
| | - Jianjun Chen
- Mid-Florida Research and Education Center, Environmental Horticulture Department, Institute of Food and Agricultural Sciences, University of Florida, Apopka, FL 32703, USA
| | - Jiahua Xie
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA; (C.-Y.H.); (F.S.K.); (J.Z.); (C.E.O.)
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Yang C, Shi G, Li Y, Luo M, Wang H, Wang J, Yuan L, Wang Y, Li Y. Genome-Wide Identification of SnRK1 Catalytic α Subunit and FLZ Proteins in Glycyrrhiza inflata Bat. Highlights Their Potential Roles in Licorice Growth and Abiotic Stress Responses. Int J Mol Sci 2022; 24:ijms24010121. [PMID: 36613561 PMCID: PMC9820696 DOI: 10.3390/ijms24010121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/04/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
Sucrose non-fermenting-1-related protein kinase-1 (SnRK1) and its scaffolding proteins, FCS-like zinc finger proteins (FLZs), are well conserved in land plants and involved in various processes of plant growth and stress responses. Glycyrrhiza inflata Bat. is a widely used licorice species with strong abiotic stress resistance, in which terpenoids and flavonoids are the major bioactive components. Here, we identified 2 SnRK1 catalytic α subunit encoding genes (GiSnRK1α1 and GiSnRK1α2) and 21 FLZ genes in G. inflata. Polygenetic analysis showed that the 21 GiFLZs could be divided into three groups. A total of 10 representative GiFLZ proteins interact with GiSnRK1α1, and they display overlapped subcellular localization (mainly in the nucleus and the cytoplasm) when transiently expressed in Nicotiana benthamiana leaf cells. Coinciding with the existence of various phytohormone-responsive and stress-responsive cis-regulatory elements in the GiSnRK1α and GiFLZ gene promoters, GiFLZs are actively responsive to methyl jasmonic acid (MeJA) and abscisic acid (ABA) treatments, and several GiFLZs and GiSnRK1α1 are regulated by drought and saline-alkaline stresses. Interestingly, GiSnRK1α and 20 of 21 GiFLZs (except for GiFLZ2) show higher expression in the roots than in the leaves. These data provide comprehensive information on the SnRK1 catalytic α subunit and the FLZ proteins in licorice for future functional characterization.
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Affiliation(s)
- Chao Yang
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guangyu Shi
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuping Li
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ming Luo
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongxia Wang
- Shanghai Key Laboratory of Plant Functional Genomics and Resources, Shanghai Chenshan Botanical Garden, Shanghai 201602, China
| | - Jihua Wang
- Key Laboratory of Crops Genetic Improvement of Guangdong, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Ling Yuan
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40506, USA
| | - Ying Wang
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Guangdong Provincial Key Laboratory of Digital Botanical Garden, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Correspondence: (Y.W.); (Y.L.)
| | - Yongqing Li
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: (Y.W.); (Y.L.)
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Ruiz-Gayosso A, Rodríguez-Cruz I, Martínez-Barajas E, Coello P. Phosphorylation of DPE2 at S786 partially regulates starch degradation. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 193:70-77. [PMID: 36335878 DOI: 10.1016/j.plaphy.2022.10.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/10/2022] [Accepted: 10/22/2022] [Indexed: 06/16/2023]
Abstract
In plants, transitory starch is synthetized during the day and degraded at night to provide the continuous carbon needed for growth and development. Starch metabolism is highly coordinated, as the starch degradation rate must be coupled to the amount of starch synthetized during the day. Maltose is one of the chloroplastic products obtained from starch degradation, and maltose is exported to the cytosol where disproportionating enzyme-2 (DPE2) is responsible for its metabolism. The amount of DPE2 remained unchanged throughout the day, but its activity notably increased at the end of the day (7 p.m.), suggesting that posttranslational modification drives the mechanism underlying the regulatory activity of this enzyme. Sucrose nonfermenting-related kinase-1 (SnRK1), a protein kinase that controls the activity of several metabolic enzymes, was able to interact and phosphorylate DPE2 at three different residues localized in the α-glucanotransferase domain. This phosphorylation acts as a positive regulator of DPE2, increasing its activity. Complementation of dpe2-deficient mutants with the wild-type (WT) and S786A forms of DPE2 showed that the nonphosphorylated form of DPE2 only partially restored starch degradation, suggesting that phosphorylation at S786 is involved in enzyme regulation.
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Affiliation(s)
- A Ruiz-Gayosso
- Departamento de Bioquímica, Facultad de Química, UNAM, Cd. Mx, 04510, Mexico
| | - I Rodríguez-Cruz
- Departamento de Bioquímica, Facultad de Química, UNAM, Cd. Mx, 04510, Mexico
| | - E Martínez-Barajas
- Departamento de Bioquímica, Facultad de Química, UNAM, Cd. Mx, 04510, Mexico
| | - P Coello
- Departamento de Bioquímica, Facultad de Química, UNAM, Cd. Mx, 04510, Mexico.
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Gutierrez-Beltran E, Crespo JL. Compartmentalization, a key mechanism controlling the multitasking role of the SnRK1 complex. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:7055-7067. [PMID: 35861169 PMCID: PMC9664234 DOI: 10.1093/jxb/erac315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
SNF1-related protein kinase 1 (SnRK1), the plant ortholog of mammalian AMP-activated protein kinase/fungal (yeast) Sucrose Non-Fermenting 1 (AMPK/SNF1), plays a central role in metabolic responses to reduced energy levels in response to nutritional and environmental stresses. SnRK1 functions as a heterotrimeric complex composed of a catalytic α- and regulatory β- and βγ-subunits. SnRK1 is a multitasking protein involved in regulating various cellular functions, including growth, autophagy, stress response, stomatal development, pollen maturation, hormone signaling, and gene expression. However, little is known about the mechanism whereby SnRK1 ensures differential execution of downstream functions. Compartmentalization has been recently proposed as a new key mechanism for regulating SnRK1 signaling in response to stimuli. In this review, we discuss the multitasking role of SnRK1 signaling associated with different subcellular compartments.
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Affiliation(s)
| | - Jose L Crespo
- Instituto de Bioquimica Vegetal y Fotosintesis, Consejo Superior de Investigaciones Cientificas (CSIC)-Universidad de Sevilla, Sevilla, Spain
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9
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Zacharaki V, Ponnu J, Crepin N, Langenecker T, Hagmann J, Skorzinski N, Musialak‐Lange M, Wahl V, Rolland F, Schmid M. Impaired KIN10 function restores developmental defects in the Arabidopsis trehalose 6-phosphate synthase1 (tps1) mutant. THE NEW PHYTOLOGIST 2022; 235:220-233. [PMID: 35306666 PMCID: PMC9320823 DOI: 10.1111/nph.18104] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 03/09/2022] [Indexed: 05/19/2023]
Abstract
Sensing carbohydrate availability is essential for plants to coordinate their growth and development. In Arabidopsis thaliana, TREHALOSE 6-PHOSPHATE SYNTHASE 1 (TPS1) and its product, trehalose 6-phosphate (T6P), are important for the metabolic control of development. tps1 mutants are embryo-lethal and unable to flower when embryogenesis is rescued. T6P regulates development in part through inhibition of SUCROSE NON-FERMENTING1 RELATED KINASE1 (SnRK1). Here, we explored the role of SnRK1 in T6P-mediated plant growth and development using a combination of a mutant suppressor screen and genetic, cellular and transcriptomic approaches. We report nonsynonymous amino acid substitutions in the catalytic KIN10 and regulatory SNF4 subunits of SnRK1 that can restore both embryogenesis and flowering of tps1 mutant plants. The identified SNF4 point mutations disrupt the interaction with the catalytic subunit KIN10. Contrary to the common view that the two A. thaliana SnRK1 catalytic subunits act redundantly, we found that loss-of-function mutations in KIN11 are unable to restore embryogenesis and flowering, highlighting the important role of KIN10 in T6P signalling.
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Affiliation(s)
- Vasiliki Zacharaki
- Department of Plant PhysiologyUmeå Plant Science CentreUmeå UniversitySE‐901 87UmeåSweden
| | - Jathish Ponnu
- Department of Molecular BiologyMax Planck Institute for Developmental BiologySpemannstr. 3572076TübingenGermany
- Institute for Plant SciencesCologne BiocenterUniversität zu KölnZülpicher Straße 47b50674KölnGermany
| | - Nathalie Crepin
- Laboratory for Molecular Plant BiologyBiology DepartmentUniversity of Leuven–KU LeuvenKasteelpark Arenberg 313001Heverlee‐LeuvenBelgium
- KU Leuven Plant Institute (LPI)3001Heverlee‐LeuvenBelgium
| | - Tobias Langenecker
- Department of Molecular BiologyMax Planck Institute for Developmental BiologySpemannstr. 3572076TübingenGermany
| | - Jörg Hagmann
- Department of Molecular BiologyMax Planck Institute for Developmental BiologySpemannstr. 3572076TübingenGermany
| | - Noemi Skorzinski
- Department of Plant PhysiologyUmeå Plant Science CentreUmeå UniversitySE‐901 87UmeåSweden
- Department of Molecular BiologyMax Planck Institute for Developmental BiologySpemannstr. 3572076TübingenGermany
| | - Magdalena Musialak‐Lange
- Department of Plant Reproductive Biology and EpigeneticsMax Planck Institute of Molecular Plant PhysiologyAm Mühlenberg 114476PotsdamGermany
| | - Vanessa Wahl
- Department of Plant Reproductive Biology and EpigeneticsMax Planck Institute of Molecular Plant PhysiologyAm Mühlenberg 114476PotsdamGermany
| | - Filip Rolland
- Laboratory for Molecular Plant BiologyBiology DepartmentUniversity of Leuven–KU LeuvenKasteelpark Arenberg 313001Heverlee‐LeuvenBelgium
- KU Leuven Plant Institute (LPI)3001Heverlee‐LeuvenBelgium
| | - Markus Schmid
- Department of Plant PhysiologyUmeå Plant Science CentreUmeå UniversitySE‐901 87UmeåSweden
- Department of Molecular BiologyMax Planck Institute for Developmental BiologySpemannstr. 3572076TübingenGermany
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10
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Yang F, Miao Y, Liu Y, Botella JR, Li W, Li K, Song CP. Function of Protein Kinases in Leaf Senescence of Plants. FRONTIERS IN PLANT SCIENCE 2022; 13:864215. [PMID: 35548290 PMCID: PMC9083415 DOI: 10.3389/fpls.2022.864215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/14/2022] [Indexed: 06/15/2023]
Abstract
Leaf senescence is an evolutionarily acquired process and it is critical for plant fitness. During senescence, macromolecules and nutrients are disassembled and relocated to actively growing organs. Plant leaf senescence process can be triggered by developmental cues and environmental factors, proper regulation of this process is essential to improve crop yield. Protein kinases are enzymes that modify their substrates activities by changing the conformation, stability, and localization of those proteins, to play a crucial role in the leaf senescence process. Impressive progress has been made in understanding the role of different protein kinases in leaf senescence recently. This review focuses on the recent progresses in plant leaf senescence-related kinases. We summarize the current understanding of the function of kinases on senescence signal perception and transduction, to help us better understand how the orderly senescence degeneration process is regulated by kinases, and how the kinase functions in the intricate integration of environmental signals and leaf age information.
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Affiliation(s)
- Fengbo Yang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Yuchen Miao
- State Key Laboratory of Cotton Biology, Henan Joint International Laboratory for Crop Multi-Omics Research, School of Life Sciences, Henan University, Kaifeng, China
| | - Yuyue Liu
- State Key Laboratory of Cotton Biology, Henan Joint International Laboratory for Crop Multi-Omics Research, School of Life Sciences, Henan University, Kaifeng, China
| | - Jose R. Botella
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD, Australia
| | - Weiqiang Li
- State Key Laboratory of Cotton Biology, Henan Joint International Laboratory for Crop Multi-Omics Research, School of Life Sciences, Henan University, Kaifeng, China
| | - Kun Li
- State Key Laboratory of Cotton Biology, Henan Joint International Laboratory for Crop Multi-Omics Research, School of Life Sciences, Henan University, Kaifeng, China
| | - Chun-Peng Song
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
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11
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Peixoto B, Moraes TA, Mengin V, Margalha L, Vicente R, Feil R, Höhne M, Sousa AGG, Lilue J, Stitt M, Lunn JE, Baena-González E. Impact of the SnRK1 protein kinase on sucrose homeostasis and the transcriptome during the diel cycle. PLANT PHYSIOLOGY 2021; 187:1357-1373. [PMID: 34618060 PMCID: PMC8566312 DOI: 10.1093/plphys/kiab350] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/09/2021] [Indexed: 05/04/2023]
Abstract
SNF1-related Kinase 1 (SnRK1) is an evolutionarily conserved protein kinase with key functions in energy management during stress responses in plants. To address a potential role of SnRK1 under favorable conditions, we performed a metabolomic and transcriptomic characterization of rosettes of 20-d-old Arabidopsis (Arabidopsis thaliana) plants of SnRK1 gain- and loss-of-function mutants during the regular diel cycle. Our results show that SnRK1 manipulation alters the sucrose and trehalose 6-phosphate (Tre6P) relationship, influencing how the sucrose content is translated into Tre6P accumulation and modulating the flux of carbon to the tricarboxylic acid cycle downstream of Tre6P signaling. On the other hand, daily cycles of Tre6P accumulation were accompanied by changes in SnRK1 signaling, leading to a maximum in the expression of SnRK1-induced genes at the end of the night, when Tre6P levels are lowest, and to a minimum at the end of the day, when Tre6P levels peak. The expression of SnRK1-induced genes was strongly reduced by transient Tre6P accumulation in an inducible Tre6P synthase (otsA) line, further suggesting the involvement of Tre6P in the diel oscillations in SnRK1 signaling. Transcriptional profiling of wild-type plants and SnRK1 mutants also uncovered defects that are suggestive of an iron sufficiency response and of a matching induction of sulfur acquisition and assimilation when SnRK1 is depleted. In conclusion, under favorable growth conditions, SnRK1 plays a role in sucrose homeostasis and transcriptome remodeling in autotrophic tissues and its activity is influenced by diel fluctuations in Tre6P levels.
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Affiliation(s)
- Bruno Peixoto
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal and GREEN-IT Bioresources for Sustainability, ITQB NOVA, 2780-157 Oeiras, Portugal
| | - Thiago A Moraes
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
- Present address: Crop Science Centre, Lawrence Weaver Road, Cambridge CB3 0LE, UK
| | - Virginie Mengin
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
- Present address: University of Essex, School of Life Sciences, Wivenhoe Park, Colchester CO4 3SQ, UK
| | - Leonor Margalha
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal and GREEN-IT Bioresources for Sustainability, ITQB NOVA, 2780-157 Oeiras, Portugal
| | - Rubén Vicente
- GREEN-IT Bioresources for Sustainability, ITQB NOVA, 2780-157 Oeiras, Portugal
| | - Regina Feil
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Melanie Höhne
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - António G G Sousa
- Instituto Gulbenkian de Ciência, Bioinformatics Unit, 2780-156 Oeiras, Portugal
| | - Jingtao Lilue
- Instituto Gulbenkian de Ciência, Bioinformatics Unit, 2780-156 Oeiras, Portugal
| | - Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - John E Lunn
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Elena Baena-González
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal and GREEN-IT Bioresources for Sustainability, ITQB NOVA, 2780-157 Oeiras, Portugal
- Author for communication:
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12
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Jamsheer K M, Kumar M, Srivastava V. SNF1-related protein kinase 1: the many-faced signaling hub regulating developmental plasticity in plants. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:6042-6065. [PMID: 33693699 DOI: 10.1093/jxb/erab079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 02/17/2021] [Indexed: 05/03/2023]
Abstract
The Snf1-related protein kinase 1 (SnRK1) is the plant homolog of the heterotrimeric AMP-activated protein kinase/sucrose non-fermenting 1 (AMPK/Snf1), which works as a major regulator of growth under nutrient-limiting conditions in eukaryotes. Along with its conserved role as a master regulator of sugar starvation responses, SnRK1 is involved in controlling the developmental plasticity and resilience under diverse environmental conditions in plants. In this review, through mining and analyzing the interactome and phosphoproteome data of SnRK1, we are highlighting its role in fundamental cellular processes such as gene regulation, protein synthesis, primary metabolism, protein trafficking, nutrient homeostasis, and autophagy. Along with the well-characterized molecular interaction in SnRK1 signaling, our analysis highlights several unchartered regions of SnRK1 signaling in plants such as its possible communication with chromatin remodelers, histone modifiers, and inositol phosphate signaling. We also discuss potential reciprocal interactions of SnRK1 signaling with other signaling pathways and cellular processes, which could be involved in maintaining flexibility and homeostasis under different environmental conditions. Overall, this review provides a comprehensive overview of the SnRK1 signaling network in plants and suggests many novel directions for future research.
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Affiliation(s)
- Muhammed Jamsheer K
- Amity Food & Agriculture Foundation, Amity University Uttar Pradesh, Sector 125, Noida 201313, India
| | - Manoj Kumar
- Amity Food & Agriculture Foundation, Amity University Uttar Pradesh, Sector 125, Noida 201313, India
| | - Vibha Srivastava
- Department of Crop, Soil & Environmental Sciences, University of Arkansas, Fayetteville, AR, USA
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13
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Fichtner F, Lunn JE. The Role of Trehalose 6-Phosphate (Tre6P) in Plant Metabolism and Development. ANNUAL REVIEW OF PLANT BIOLOGY 2021; 72:737-760. [PMID: 33428475 DOI: 10.1146/annurev-arplant-050718-095929] [Citation(s) in RCA: 98] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Trehalose 6-phosphate (Tre6P) has a dual function as a signal and homeostatic regulator of sucrose levels in plants. In source leaves, Tre6P regulates the production of sucrose to balance supply with demand for sucrose from growing sink organs. As a signal of sucrose availability, Tre6P influences developmental decisions that will affect future demand for sucrose, such as flowering, embryogenesis, and shoot branching, and links the growth of sink organs to sucrose supply. This involves complex interactions with SUCROSE-NON-FERMENTING1-RELATED KINASE1 that are not yet fully understood. Tre6P synthase, the enzyme that makes Tre6P, plays a key role in the nexus between sucrose and Tre6P, operating in the phloem-loading zone of leaves and potentially generating systemic signals for source-sink coordination. Many plants have large and diverse families of Tre6P phosphatase enzymes that dephosphorylate Tre6P, some of which have noncatalytic functions in plant development.
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Affiliation(s)
- Franziska Fichtner
- School of Biological Sciences, The University of Queensland, St. Lucia, Queensland 4072, Australia;
| | - John Edward Lunn
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany;
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14
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De Coninck T, Gistelinck K, Janse van Rensburg HC, Van den Ende W, Van Damme EJM. Sweet Modifications Modulate Plant Development. Biomolecules 2021; 11:756. [PMID: 34070047 PMCID: PMC8158104 DOI: 10.3390/biom11050756] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 04/28/2021] [Accepted: 05/12/2021] [Indexed: 02/07/2023] Open
Abstract
Plant development represents a continuous process in which the plant undergoes morphological, (epi)genetic and metabolic changes. Starting from pollination, seed maturation and germination, the plant continues to grow and develops specialized organs to survive, thrive and generate offspring. The development of plants and the interplay with its environment are highly linked to glycosylation of proteins and lipids as well as metabolism and signaling of sugars. Although the involvement of these protein modifications and sugars is well-studied, there is still a long road ahead to profoundly comprehend their nature, significance, importance for plant development and the interplay with stress responses. This review, approached from the plants' perspective, aims to focus on some key findings highlighting the importance of glycosylation and sugar signaling for plant development.
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Affiliation(s)
- Tibo De Coninck
- Laboratory of Glycobiology & Biochemistry, Department of Biotechnology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium; (T.D.C.); (K.G.)
| | - Koen Gistelinck
- Laboratory of Glycobiology & Biochemistry, Department of Biotechnology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium; (T.D.C.); (K.G.)
| | - Henry C. Janse van Rensburg
- Laboratory of Molecular Plant Biology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium; (H.C.J.v.R.); (W.V.d.E.)
| | - Wim Van den Ende
- Laboratory of Molecular Plant Biology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium; (H.C.J.v.R.); (W.V.d.E.)
| | - Els J. M. Van Damme
- Laboratory of Glycobiology & Biochemistry, Department of Biotechnology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium; (T.D.C.); (K.G.)
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15
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Chen S, Li X, Yang C, Yan W, Liu C, Tang X, Gao C. Genome-wide Identification and Characterization of FCS-Like Zinc Finger (FLZ) Family Genes in Maize ( Zea mays) and Functional Analysis of ZmFLZ25 in Plant Abscisic Acid Response. Int J Mol Sci 2021; 22:3529. [PMID: 33805388 PMCID: PMC8037668 DOI: 10.3390/ijms22073529] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/13/2021] [Accepted: 03/18/2021] [Indexed: 01/20/2023] Open
Abstract
FCS-like zinc finger family proteins (FLZs), a class of plant-specific scaffold of SnRK1 complex, are involved in the regulation of various aspects of plant growth and stress responses. Most information of FLZ family genes was obtained from the studies in Arabidopsis thaliana, whereas little is known about the potential functions of FLZs in crop plants. In this study, 37 maize FLZ (ZmFLZ) genes were identified to be asymmetrically distributed on 10 chromosomes and can be divided into three subfamilies. Protein interaction and subcellular localization assays demonstrated that eight typical ZmFLZs interacted and partially co-localized with ZmKIN10, the catalytic α-subunit of the SnRK1 complex in maize leaf mesophyll cells. Expression profile analysis revealed that several ZmFLZs were differentially expressed across various tissues and actively responded to diverse abiotic stresses. In addition, ectopic overexpression of ZmFLZ25 in Arabidopsis conferred hypersensitivity to exogenous abscisic acid (ABA) and triggered higher expression of ABA-induced genes, pointing to the positive regulatory role of ZmFLZ25 in plant ABA signaling, a scenario further evidenced by the interactions between ZmFLZ25 and ABA receptors. In summary, these data provide the most comprehensive information on FLZ family genes in maize, and shed light on the biological function of ZmFLZ25 in plant ABA signaling.
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Affiliation(s)
- Shunquan Chen
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China; (S.C.); (X.L.); (C.Y.); (W.Y.); (C.L.)
- Shenzhen Institute of Molecular Crop Design, Shenzhen 518107, China
| | - Xibao Li
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China; (S.C.); (X.L.); (C.Y.); (W.Y.); (C.L.)
| | - Chao Yang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China; (S.C.); (X.L.); (C.Y.); (W.Y.); (C.L.)
| | - Wei Yan
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China; (S.C.); (X.L.); (C.Y.); (W.Y.); (C.L.)
- Shenzhen Institute of Molecular Crop Design, Shenzhen 518107, China
| | - Chuanliang Liu
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China; (S.C.); (X.L.); (C.Y.); (W.Y.); (C.L.)
| | - Xiaoyan Tang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China; (S.C.); (X.L.); (C.Y.); (W.Y.); (C.L.)
- Shenzhen Institute of Molecular Crop Design, Shenzhen 518107, China
| | - Caiji Gao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China; (S.C.); (X.L.); (C.Y.); (W.Y.); (C.L.)
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16
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Wang B, Zhao X, Zhao Y, Shanklin J, Zhao Q, Liu CJ. Arabidopsis SnRK1 negatively regulates phenylpropanoid metabolism via Kelch domain-containing F-box proteins. THE NEW PHYTOLOGIST 2021; 229:3345-3359. [PMID: 33253431 DOI: 10.1111/nph.17121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/19/2020] [Indexed: 05/04/2023]
Abstract
Phenylpropanoid metabolism represents a substantial metabolic sink for photosynthetically fixed carbon. The evolutionarily conserved Sucrose Non-Fermenting Related Kinase 1 (SnRK1) is a major metabolic sensor that reprograms metabolism upon carbon deprivation. However, it is not clear if and how the SnRK1-mediated sugar signaling pathway controls phenylpropanoid metabolism. Here, we show that Arabidopsis SnRK1 negatively regulates phenylpropanoid biosynthesis via a group of Kelch domain-containing F-box (KFB) proteins that are responsible for the ubiquitination and degradation of phenylalanine ammonia lyase (PAL). Downregulation of AtSnRK1 significantly promoted the accumulation of soluble phenolics and lignin polymers and drastically increased PAL cellular accumulation but only slightly altered its transcription level. Co-expression of SnRK1α with PAL in Nicotiana benthamiana leaves resulted in the severe attenuation of the latter's protein level, but protein interaction assays suggested PAL is not a direct substrate of SnRK1. Furthermore, up or downregulation of AtSnRK1 positively affected KFBPALs gene expression, and energy starvation upregulated KFBPAL expression, which partially depends on AtSnRK1. Collectively, our study reveals that SnRK1 negatively regulates phenylpropanoid biosynthesis, and KFBPALs act as regulatory components of the SnRK1 signaling network, transcriptionally regulated by SnRK1 and subsequently mediate proteasomal degradation of PAL in response to the cellular carbon availability.
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Affiliation(s)
- Bin Wang
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xianhai Zhao
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Yunjun Zhao
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - John Shanklin
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Qiao Zhao
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Chang-Jun Liu
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
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17
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Carianopol CS, Gazzarrini S. SnRK1α1 Antagonizes Cell Death Induced by Transient Overexpression of Arabidopsis thaliana ABI5 Binding Protein 2 (AFP2). FRONTIERS IN PLANT SCIENCE 2020; 11:582208. [PMID: 33133119 PMCID: PMC7550686 DOI: 10.3389/fpls.2020.582208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 09/10/2020] [Indexed: 06/01/2023]
Abstract
Plants are continuously exposed to environmental stressors. They have thus evolved complex signaling pathways to govern responses to a variety of stimuli. The hormone abscisic acid (ABA) has been implicated in modulating both abiotic and biotic stress responses in plants. ABI5 Binding Proteins (AFPs) are a family of negative regulators of bZIP transcription factors of the AREB/ABF family, which promote ABA responses. AFP2 interacts with Snf1-Related protein Kinase 1 (SnRK1), which belongs to a highly conserved heterotrimeric kinase complex that is activated to re-establish energy homeostasis following stress. However, the role of this interaction is currently unknown. Here, we show that transient overexpression of Arabidopsis thaliana AFP2 in Nicotiana benthamiana leaves induces cell death (CD). Using truncated AFP2 constructs, we demonstrate that CD induction by AFP2 is dependent on the EAR domain. Co-expression of the catalytic subunit SnRK1α1, but not SnRK1α2, rescues AFP2-induced CD. Overexpression of SnRK1α1 has little effect on AFP2 protein level and does not affect AFP2 subcellular localization. Our results show that a high level of AFP2 is detrimental for cell function and that SnRK1α1 antagonizes AFP2-induced CD most likely through a mechanism that does not involve AFP2 protein degradation or a change in subcellular localization.
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Affiliation(s)
- Carina Steliana Carianopol
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Sonia Gazzarrini
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
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18
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Feng X, Feng P, Yu H, Yu X, Sun Q, Liu S, Minh TN, Chen J, Wang D, Zhang Q, Cao L, Zhou C, Li Q, Xiao J, Zhong S, Wang A, Wang L, Pan H, Ding X. GsSnRK1 interplays with transcription factor GsERF7 from wild soybean to regulate soybean stress resistance. PLANT, CELL & ENVIRONMENT 2020; 43:1192-1211. [PMID: 31990078 DOI: 10.1111/pce.13726] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 12/18/2019] [Accepted: 01/12/2020] [Indexed: 05/07/2023]
Abstract
Although the function and regulation of SnRK1 have been studied in various plants, its molecular mechanisms in response to abiotic stresses are still elusive. In this work, we identified an AP2/ERF domain-containing protein (designated GsERF7) interacting with GsSnRK1 from a wild soybean cDNA library. GsERF7 gene expressed dominantly in wild soybean roots and was responsive to ethylene, salt, and alkaline. GsERF7 bound GCC cis-acting element and could be phosphorylated on S36 by GsSnRK1. GsERF7 phosphorylation facilitated its translocation from cytoplasm to nucleus and enhanced its transactivation activity. When coexpressed in the hairy roots of soybean seedlings, GsSnRK1(wt) and GsERF7(wt) promoted plants to generate higher tolerance to salt and alkaline stresses than their mutated species, suggesting that GsSnRK1 may function as a biochemical and genetic upstream kinase of GsERF7 to regulate plant adaptation to environmental stresses. Furthermore, the altered expression patterns of representative abiotic stress-responsive and hormone-synthetic genes were determined in transgenic soybean hairy roots after stress treatments. These results will aid our understanding of molecular mechanism of how SnRK1 kinase plays a cardinal role in regulating plant stress resistances through activating the biological functions of downstream factors.
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Affiliation(s)
- Xu Feng
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Peng Feng
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Huilin Yu
- College of Plant Sciences, Jilin University, Changchun, 130062, China
| | - Xingyu Yu
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Qi Sun
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Siyu Liu
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Thuy Nguyen Minh
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Jun Chen
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Di Wang
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Qing Zhang
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Lei Cao
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Changmei Zhou
- College of Agronomy, Northeast Agricultural University, Harbin, 150030, China
| | - Qiang Li
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Jialei Xiao
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Shihua Zhong
- Department of Biochemistry, the University of Texas Southwestern Medical Center, Dallas, Texas, 75390
| | - Aoxue Wang
- College of Horticulture, Northeast Agricultural University, Harbin, 150030, China
| | - Lijuan Wang
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Hongyu Pan
- College of Plant Sciences, Jilin University, Changchun, 130062, China
| | - Xiaodong Ding
- Key Laboratory of Agricultural Biological Functional Genes, College of Life Science, Northeast Agricultural University, Harbin, 150030, China
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19
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Saito S, Uozumi N. Calcium-Regulated Phosphorylation Systems Controlling Uptake and Balance of Plant Nutrients. FRONTIERS IN PLANT SCIENCE 2020; 11:44. [PMID: 32117382 PMCID: PMC7026023 DOI: 10.3389/fpls.2020.00044] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 01/14/2020] [Indexed: 05/18/2023]
Abstract
Essential elements taken up from the soil and distributed throughout the whole plant play diverse roles in different tissues. Cations and anions contribute to maintenance of intracellular osmolarity and the formation of membrane potential, while nitrate, ammonium, and sulfate are incorporated into amino acids and other organic compounds. In contrast to these ion species, calcium concentrations are usually kept low in the cytosol and calcium displays unique behavior as a cytosolic signaling molecule. Various environmental stresses stimulate increases in the cytosolic calcium concentration, leading to activation of calcium-regulated protein kinases and downstream signaling pathways. In this review, we summarize the stress responsive regulation of nutrient uptake and balancing by two types of calcium-regulated phosphorylation systems: CPK and CBL-CIPK. CPK is a family of protein kinases activated by calcium. CBL is a group of calcium sensor proteins that interact with CIPK kinases, which phosphorylate their downstream targets. In Arabidopsis, quite a few ion transport systems are regulated by CPKs or CBL-CIPK complexes, including channels/transporters that mediate transport of potassium (KAT1, KAT2, GORK, AKT1, AKT2, HAK5, SPIK), sodium (SOS1), ammonium (AMT1;1, AMT1;2), nitrate and chloride (SLAC1, SLAH2, SLAH3, NRT1.1, NRT2.4, NRT2.5), and proton (AHA2, V-ATPase). CPKs and CBL-CIPKs also play a role in C/N nutrient response and in acquisition of magnesium and iron. This functional regulation by calcium-dependent phosphorylation systems ensures the growth of plants and enables them to acquire tolerance against various environmental stresses. Calcium serves as the key factor for the regulation of membrane transport systems.
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Affiliation(s)
- Shunya Saito
- *Correspondence: Shunya Saito, ; Nobuyuki Uozumi,
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20
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Perochon A, Váry Z, Malla KB, Halford NG, Paul MJ, Doohan FM. The wheat SnRK1α family and its contribution to Fusarium toxin tolerance. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 288:110217. [PMID: 31521211 DOI: 10.1016/j.plantsci.2019.110217] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 08/06/2019] [Accepted: 08/09/2019] [Indexed: 05/09/2023]
Abstract
Deoxynivalenol (DON) is a mycotoxin produced by phytopathogenic Fusarium fungi in cereal grain and plays a role as a disease virulence factor. TaFROG (Triticum aestivum Fusarium Resistance Orphan Gene) enhances wheat resistance to DON and it interacts with a sucrose non-fermenting-1 (SNF1)-related protein kinase 1 catalytic subunit α (SnRK1α). This protein kinase family is central integrator of stress and energy signalling, regulating plant metabolism and growth. Little is known regarding the role of SnRK1α in the biotic stress response, especially in wheat. In this study, 15 wheat (Triticum aestivum) SnRK1α genes (TaSnRK1αs) belonging to four homoeologous groups were identified in the wheat genome. TaSnRK1αs are expressed ubiquitously in all organs and developmental stages apart from two members predominantly detected in grain. While DON treatment had either no effect or downregulated the transcription of TaSnRK1αs, it increased both the kinase activity associated with SnRK1α and the level of active (phosphorylated) SnRK1α. Down-regulation of two TaSnRK1αs homoeolog groups using virus induced gene silencing (VIGS) increased the DON-induced damage of wheat spikelets. Thus, we demonstrate that TaSnRK1αs contribute positively to wheat tolerance of DON and conclude that this gene family may provide useful tools for the improvement of crop biotic stress resistance.
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Affiliation(s)
- Alexandre Perochon
- UCD School of Biology and Environmental Science and Earth Institute, College of Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Zsolt Váry
- UCD School of Biology and Environmental Science and Earth Institute, College of Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Keshav B Malla
- UCD School of Biology and Environmental Science and Earth Institute, College of Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Nigel G Halford
- Plant Sciences Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom.
| | - Matthew J Paul
- Plant Sciences Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom.
| | - Fiona M Doohan
- UCD School of Biology and Environmental Science and Earth Institute, College of Science, University College Dublin, Belfield, Dublin 4, Ireland.
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21
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Bruns AN, Li S, Mohannath G, Bisaro DM. Phosphorylation of Arabidopsis eIF4E and eIFiso4E by SnRK1 inhibits translation. FEBS J 2019; 286:3778-3796. [PMID: 31120171 DOI: 10.1111/febs.14935] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/28/2019] [Accepted: 05/21/2019] [Indexed: 01/01/2023]
Abstract
Regulation of protein synthesis is critical for maintaining cellular homeostasis. In mammalian systems, translational regulatory networks have been elucidated in considerable detail. In plants, however, regulation occurs through different mechanisms that remain largely elusive. In this study, we present evidence that the Arabidopsis thaliana energy sensing kinase SnRK1, a homologue of mammalian AMP-activated kinase and yeast sucrose non-fermenting 1 (SNF1), inhibits translation by phosphorylating the cap binding proteins eIF4E and eIFiso4E. We establish that eIF4E and eIFiso4E contain two deeply conserved SnRK1 consensus target sites and that both interact with SnRK1 in vivo. We then demonstrate that SnRK1 phosphorylation inhibits the ability of Arabidopsis eIF4E and eIFiso4E to complement a yeast strain lacking endogenous eIF4E, and that inhibition correlates with repression of polysome formation. Finally, we show that SnRK1 over-expression in Nicotiana benthamiana plants reduces polysome formation, and that this effect can be counteracted by transient expression of eIF4E or mutant eIF4E containing non-phosphorylatable SnRK1 target residues, but not by a phosphomimic eIF4E. Together, these studies elucidate a novel and direct pathway for translational control in plant cells. In light of previous findings that SnRK1 conditions an innate antiviral defense and is inhibited by geminivirus pathogenicity factors, we speculate that phosphorylation of cap binding proteins may be a component of the resistance mechanism.
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Affiliation(s)
- Aaron N Bruns
- Department of Molecular Genetics, Center for Applied Plant Sciences, Center for RNA Biology, and Infectious Diseases Institute, The Ohio State University, Columbus, OH, USA.,Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA
| | - Sizhun Li
- Department of Molecular Genetics, Center for Applied Plant Sciences, Center for RNA Biology, and Infectious Diseases Institute, The Ohio State University, Columbus, OH, USA
| | - Gireesha Mohannath
- Department of Molecular Genetics, Center for Applied Plant Sciences, Center for RNA Biology, and Infectious Diseases Institute, The Ohio State University, Columbus, OH, USA
| | - David M Bisaro
- Department of Molecular Genetics, Center for Applied Plant Sciences, Center for RNA Biology, and Infectious Diseases Institute, The Ohio State University, Columbus, OH, USA.,Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA
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22
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Rigoulot SB, Petzold HE, Williams SP, Brunner AM, Beers EP. Populus trichocarpa clade A PP2C protein phosphatases: their stress-induced expression patterns, interactions in core abscisic acid signaling, and potential for regulation of growth and development. PLANT MOLECULAR BIOLOGY 2019; 100:303-317. [PMID: 30945147 DOI: 10.1007/s11103-019-00861-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/26/2019] [Indexed: 05/26/2023]
Abstract
Overexpression of the poplar PP2C protein phosphatase gene PtrHAB2 resulted in increased tree height and altered leaf morphology and phyllotaxy, implicating PP2C phosphatases as growth regulators functioning under favorable conditions. We identified and studied Populus trichocarpa genes, PtrHAB1 through PtrHAB15, belonging to the clade A PP2C family of protein phosphatases known to regulate abscisic acid (ABA) signaling. PtrHAB1 through PtrHAB3 and PtrHAB12 through PtrHAB15 were the most highly expressed genes under non-stress conditions. The poplar PP2C genes were differentially regulated by drought treatments. Expression of PtrHAB1 through PtrHAB3 was unchanged or downregulated in response to drought, while all other PtrHAB genes were weakly to strongly upregulated in response to drought stress treatments. Yeast two-hybrid assays involving seven ABA receptor proteins (PtrRCAR) against 12 PtrHAB proteins detected 51 interactions involving eight PP2Cs and all PtrRCAR proteins with 22 interactions requiring the addition of ABA. PtrHAB2, PtrHAB12, PtrHAB13 and PtrHAB14 also interacted with the sucrose non-fermenting related kinase 2 proteins PtrSnRK2.10 and PtrSnRK2.11, supporting conservation of a SnRK2 signaling cascade regulated by PP2C in poplar. Additionally, PtrHAB2, PtrHAB12, PtrHAB13 and PtrHAB14 interacted with the mitogen-activated protein kinase protein PtrMPK7. Due to its interactions with PtrSnRK2 and PtrMPK7 proteins, and its reduced expression during drought stress, PtrHAB2 was overexpressed in poplar to test its potential as a growth regulator under non-stress conditions. 35S::PtrHAB2 transgenics exhibited increased growth rate for a majority of transgenic events and alterations in leaf phyllotaxy and morphology. These results indicate that PP2Cs have additional roles which extend beyond canonical ABA signaling, possibly coordinating plant growth and development in response to environmental conditions.
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Affiliation(s)
- Stephen B Rigoulot
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
- Department of Plant Sciences, University of Tennessee, Knoxville, TN, 37996, USA
| | - H Earl Petzold
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Sarah P Williams
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, 24061, USA
- Department of Biology, College of William and Mary, Williamsburg, VA, 23187, USA
| | - Amy M Brunner
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Eric P Beers
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, 24061, USA.
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23
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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: 54] [Impact Index Per Article: 10.8] [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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24
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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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25
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Wang J, Guan H, Dong R, Liu C, Liu Q, Liu T, Wang L, He C. Overexpression of maize sucrose non-fermenting-1-related protein kinase 1 genes, ZmSnRK1s, causes alteration in carbon metabolism and leaf senescence in Arabidopsis thaliana. Gene 2019; 691:34-44. [DOI: 10.1016/j.gene.2018.12.039] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/23/2018] [Accepted: 12/14/2018] [Indexed: 12/18/2022]
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26
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Janse van Rensburg HC, Van den Ende W, Signorelli S. Autophagy in Plants: Both a Puppet and a Puppet Master of Sugars. FRONTIERS IN PLANT SCIENCE 2019; 10:14. [PMID: 30723485 PMCID: PMC6349728 DOI: 10.3389/fpls.2019.00014] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/07/2019] [Indexed: 05/20/2023]
Abstract
Autophagy is a major pathway that recycles cellular components in eukaryotic cells both under stressed and non-stressed conditions. Sugars participate both metabolically and as signaling molecules in development and response to various environmental and nutritional conditions. It is therefore essential to maintain metabolic homeostasis of sugars during non-stressed conditions in cells, not only to provide energy, but also to ensure effective signaling when exposed to stress. In both plants and animals, autophagy is activated by the energy sensor SnRK1/AMPK and inhibited by TOR kinase. SnRK1/AMPK and TOR kinases are both important regulators of cellular metabolism and are controlled to a large extent by the availability of sugars and sugar-phosphates in plants whereas in animals AMP/ATP indirectly translate sugar status. In plants, during nutrient and sugar deficiency, SnRK1 is activated, and TOR is inhibited to allow activation of autophagy which in turn recycles cellular components in an attempt to provide stress relief. Autophagy is thus indirectly regulated by the nutrient/sugar status of cells, but also regulates the level of nutrients/sugars by recycling cellular components. In both plants and animals sugars such as trehalose induce autophagy and in animals this is independent of the TOR pathway. The glucose-activated G-protein signaling pathway has also been demonstrated to activate autophagy, although the exact mechanism is not completely clear. This mini-review will focus on the interplay between sugar signaling and autophagy.
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Affiliation(s)
| | - Wim Van den Ende
- Laboratory of Molecular Plant Biology, KU Leuven, Leuven, Belgium
| | - Santiago Signorelli
- Laboratory of Molecular Plant Biology, KU Leuven, Leuven, Belgium
- Departamento de Biologiía Vegetal, Facultad de Agronomía, Universidad de la Repuíblica, Montevideo, Uruguay
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27
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Macovei A, Pagano A, Cappuccio M, Gallotti L, Dondi D, De Sousa Araujo S, Fevereiro P, Balestrazzi A. A Snapshot of the Trehalose Pathway During Seed Imbibition in Medicago truncatula Reveals Temporal- and Stress-Dependent Shifts in Gene Expression Patterns Associated With Metabolite Changes. FRONTIERS IN PLANT SCIENCE 2019; 10:1590. [PMID: 31921241 PMCID: PMC6930686 DOI: 10.3389/fpls.2019.01590] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 11/12/2019] [Indexed: 05/21/2023]
Abstract
Trehalose, a non-reducing disaccharide with multiple functions, among which source of energy and carbon, stress protectant, and signaling molecule, has been mainly studied in relation to plant development and response to stress. The trehalose pathway is conserved among different organisms and is composed of three enzymes: trehalose-6-phosphate synthase (TPS), which converts uridine diphosphate (UDP)-glucose and glucose-6-phosphate to trehalose-6-phosphate (T6P), trehalose-6-phosphatase (TPP), which dephosphorylates T6P to produce trehalose, and trehalase (TRE), responsible for trehalose catabolism. In plants, the trehalose pathway has been mostly studied in resurrection plants and the model plant Arabidopsis thaliana, where 11 AtTPS, 10 AtTPP, and 1 AtTRE genes are present. Here, we aim to investigate the involvement of the trehalose pathway in the early stages of seed germination (specifically, seed imbibition) using the model legume Medicago truncatula as a working system. Since not all the genes belonging to the trehalose pathway had been identified in M. truncatula, we first conducted an in silico analysis using the orthologous gene sequences from A. thaliana. Nine MtTPSs, eight MtTPPs, and a single MtTRE gene were hereby identified. Subsequently, the expression profiles of all the genes (together with the sucrose master-regulator SnRK1) were investigated during seed imbibition with water or stress agents (polyethylene glycol and sodium chloride). The reported data show a temporal distribution and preferential expression of specific TPS and TPP isoforms during seed imbibition with water. Moreover, it was possible to distinguish a small set of genes (e.g., MtTPS1, MtTPS7, MtTPS10, MtTPPA, MtTPPI, MtTRE) having a potential impact as precocious hallmarks of the seed response to stress. When the trehalose levels were measured by high-performance liquid chromatography, a significant decrease was observed during seed imbibition, suggesting that trehalose may act as an energy source rather than osmoprotectant. This is the first report investigating the expression profiles of genes belonging to the trehalose pathway during seed imbibition, thus ascertaining their involvement in the pre-germinative metabolism and their potential as tools to improve seed germination efficiency.
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Affiliation(s)
- Anca Macovei
- Department of Biology and Biotechnology “L. Spallanzani,” University of Pavia, Pavia, Italy
| | - Andrea Pagano
- Department of Biology and Biotechnology “L. Spallanzani,” University of Pavia, Pavia, Italy
| | - Michela Cappuccio
- Department of Biology and Biotechnology “L. Spallanzani,” University of Pavia, Pavia, Italy
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB-NOVA), Green-it Research Unit, Oeiras, Portugal
| | - Lucia Gallotti
- Department of Chemistry, University of Pavia, Pavia, Italy
| | - Daniele Dondi
- Department of Chemistry, University of Pavia, Pavia, Italy
| | - Susana De Sousa Araujo
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB-NOVA), Green-it Research Unit, Oeiras, Portugal
| | - Pedro Fevereiro
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB-NOVA), Green-it Research Unit, Oeiras, Portugal
- Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
| | - Alma Balestrazzi
- Department of Biology and Biotechnology “L. Spallanzani,” University of Pavia, Pavia, Italy
- *Correspondence: Alma Balestrazzi,
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28
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Wang X, Hao L, Zhu B, Jiang Z. Plant Calcium Signaling in Response to Potassium Deficiency. Int J Mol Sci 2018; 19:E3456. [PMID: 30400321 PMCID: PMC6275041 DOI: 10.3390/ijms19113456] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 10/19/2018] [Accepted: 11/01/2018] [Indexed: 01/23/2023] Open
Abstract
Potassium (K⁺) is an essential macronutrient of living cells and is the most abundant cation in the cytosol. K⁺ plays a role in several physiological processes that support plant growth and development. However, soil K⁺ availability is very low and variable, which leads to severe reductions in plant growth and yield. Various K⁺ shortage-activated signaling cascades exist. Among these, calcium signaling is the most important signaling system within plant cells. This review is focused on the possible roles of calcium signaling in plant responses to low-K⁺ stress. In plants, intracellular calcium levels are first altered in response to K⁺ deficiency, resulting in calcium signatures that exhibit temporal and spatial features. In addition, calcium channels located within the root epidermis and root hair zone can then be activated by hyperpolarization of plasma membrane (PM) in response to low-K⁺ stress. Afterward, calcium sensors, including calmodulin (CaM), CaM-like protein (CML), calcium-dependent protein kinase (CDPK), and calcineurin B-like protein (CBL), can act in the sensing of K⁺ deprivation. In particular, the important components regarding CBL/CBL-interacting protein kinase (CBL/CIPK) complexes-involved in plant responses to K⁺ deficiency are also discussed.
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Affiliation(s)
- Xiaoping Wang
- Shenzhen Key Laboratory of Marine Bioresource & Eco-environmental Science, Guangdong Engineering Research Center for Marine Algal Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China.
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Ling Hao
- Shenzhen Key Laboratory of Marine Bioresource & Eco-environmental Science, Guangdong Engineering Research Center for Marine Algal Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China.
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Biping Zhu
- Shenzhen Key Laboratory of Marine Bioresource & Eco-environmental Science, Guangdong Engineering Research Center for Marine Algal Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China.
| | - Zhonghao Jiang
- Shenzhen Key Laboratory of Marine Bioresource & Eco-environmental Science, Guangdong Engineering Research Center for Marine Algal Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China.
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
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Ruiz-Gayosso A, Rodríguez-Sotres R, Martínez-Barajas E, Coello P. A role for the carbohydrate-binding module (CBM) in regulatory SnRK1 subunits: the effect of maltose on SnRK1 activity. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:163-175. [PMID: 30003611 DOI: 10.1111/tpj.14026] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/19/2018] [Accepted: 06/26/2018] [Indexed: 06/08/2023]
Abstract
SnRK1 is a protein kinase complex that is involved in several aspects of plant growth and development. There are published data indicative of a participation of SnRK1 in the regulation of the synthesis and degradation of starch, although the molecular mechanism is not known. In this work, we performed electron microscopy to explore the in vivo localization of the regulatory and catalytic subunits that constitute the SnRK1 complex. The results indicated that all the subunits are present in the chloroplast and, in particular, the SnRK1 βγ and SnRK1 β3 subunits are associated with starch. Furthermore, the regulatory subunits bind maltose, a relevant product of starch degradation. The kinase activity of immunoprecipitated complexes containing the βγ regulatory subunit was positively regulated by maltose only in the complexes obtained from Arabidopsis leaves collected at dusk. Recombinant complexes with the SnRK1α1 catalytic subunit, SnRK1βγ and three different β subunits showed that maltose only had an effect on a complex formed with the β3 subunit. Truncation of the CBM domain form SnRK1 βγ abolished the maltose activation of the complex and the activity was significantly reduced, indicating that the CBM is a positive regulator of SnRK1. A model of the SnRK1α1/βγ/β3 complex suggests the presence of two putative maltose-binding sites, both involving ligand interactions with the βγ subunit and the α subunit.
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Affiliation(s)
- Ana Ruiz-Gayosso
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, 04510, Ciudad de México, México
| | - Rogelio Rodríguez-Sotres
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, 04510, Ciudad de México, México
| | - Eleazar Martínez-Barajas
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, 04510, Ciudad de México, México
| | - Patricia Coello
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, 04510, Ciudad de México, México
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30
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Shen W, Bobay BG, Greeley LA, Reyes MI, Rajabu CA, Blackburn RK, Dallas MB, Goshe MB, Ascencio-Ibáñez JT, Hanley-Bowdoin L. Sucrose Nonfermenting 1-Related Protein Kinase 1 Phosphorylates a Geminivirus Rep Protein to Impair Viral Replication and Infection. PLANT PHYSIOLOGY 2018; 178:372-389. [PMID: 30006378 PMCID: PMC6130039 DOI: 10.1104/pp.18.00268] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/29/2018] [Indexed: 05/17/2023]
Abstract
Geminiviruses are single-stranded DNA viruses that infect a wide variety of plants and cause severe crop losses worldwide. The geminivirus replication initiator protein (Rep) binds to the viral replication origin and catalyzes DNA cleavage and ligation to initiate rolling circle replication. In this study, we found that the Tomato golden mosaic virus (TGMV) Rep is phosphorylated at serine-97 by sucrose nonfermenting 1-related protein kinase 1 (SnRK1), a master regulator of plant energy homeostasis and metabolism. Phosphorylation of Rep or the phosphomimic S97D mutation impaired Rep binding to viral DNA. A TGMV DNA-A replicon containing the Rep S97D mutation replicated less efficiently in tobacco (Nicotiana tabacum) protoplasts than in wild-type or Rep phosphorylation-deficient replicons. The TGMV Rep-S97D mutant also was less infectious than the wild-type virus in Nicotiana benthamiana and was unable to infect tomato (Solanum lycopersicum). Nearly all geminivirus Rep proteins have a serine residue at the position equivalent to TGMV Rep serine-97. SnRK1 phosphorylated the equivalent serines in the Rep proteins of Tomato mottle virus and Tomato yellow leaf curl virus and reduced DNA binding, suggesting that SnRK1 plays a key role in combating geminivirus infection. These results established that SnRK1 phosphorylates Rep and interferes with geminivirus replication and infection, underscoring the emerging role for SnRK1 in the host defense response against plant pathogens.
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Affiliation(s)
- Wei Shen
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695-7651
| | - Benjamin G Bobay
- Duke University NMR Center, Duke University Medical Center, Duke University, Durham, North Carolina 27708
| | - Laura A Greeley
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7622
| | - Maria I Reyes
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695-7651
| | - Cyprian A Rajabu
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695-7651
- Department of Horticulture, Jomo Kenyatta University of Agriculture and Technology, 00200 Nairobi, Kenya
| | - R Kevin Blackburn
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7622
| | - Mary Beth Dallas
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695-7651
| | - Michael B Goshe
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7622
| | - Jose T Ascencio-Ibáñez
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7622
| | - Linda Hanley-Bowdoin
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695-7651
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Dong S, Zhang J, Beckles DM. A pivotal role for starch in the reconfiguration of 14C-partitioning and allocation in Arabidopsis thaliana under short-term abiotic stress. Sci Rep 2018; 8:9314. [PMID: 29915332 PMCID: PMC6006365 DOI: 10.1038/s41598-018-27610-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 05/31/2018] [Indexed: 11/09/2022] Open
Abstract
Plant carbon status is optimized for normal growth but is affected by abiotic stress. Here, we used 14C-labeling to provide the first holistic picture of carbon use changes during short-term osmotic, salinity, and cold stress in Arabidopsis thaliana. This could inform on the early mechanisms plants use to survive adverse environment, which is important for efficient agricultural production. We found that carbon allocation from source to sinks, and partitioning into major metabolite pools in the source leaf, sink leaves and roots showed both conserved and divergent responses to the stresses examined. Carbohydrates changed under all abiotic stresses applied; plants re-partitioned 14C to maintain sugar levels under stress, primarily by reducing 14C into the storage compounds in the source leaf, and decreasing 14C into the pools used for growth processes in the roots. Salinity and cold increased 14C-flux into protein, but as the stress progressed, protein degradation increased to produce amino acids, presumably for osmoprotection. Our work also emphasized that stress regulated the carbon channeled into starch, and its metabolic turnover. These stress-induced changes in starch metabolism and sugar export in the source were partly accompanied by transcriptional alteration in the T6P/SnRK1 regulatory pathway that are normally activated by carbon starvation.
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Affiliation(s)
- Shaoyun Dong
- Department of Plant Sciences, University of California, One Shield Avenue, Davis, CA, 95616, USA
| | - Joshua Zhang
- Department of Plant Sciences, University of California, One Shield Avenue, Davis, CA, 95616, USA
| | - Diane M Beckles
- Department of Plant Sciences, University of California, One Shield Avenue, Davis, CA, 95616, USA.
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Sánchez-Villarreal A, Davis AM, Davis SJ. AKIN10 activity as a cellular link between metabolism and circadian-clock entrainment in Arabidopsis thaliana. PLANT SIGNALING & BEHAVIOR 2018; 13:e1411448. [PMID: 29231782 PMCID: PMC5927675 DOI: 10.1080/15592324.2017.1411448] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/26/2017] [Accepted: 11/27/2017] [Indexed: 05/19/2023]
Abstract
AKIN10, the catalytic subunit of the Snf1 (sucrose non-fermenting 1)-related kinase 1 (SnRK1) complex, acts as an energy sensor in plants. We showed that AKIN10-induced expression affects the pace of the circadian clock and particularly the phase of expression of GIGANTEA (GI). The AKIN10 effect on period length required TIME FOR COFFEE (TIC), a circadian-clock component with developmental and metabolic roles. Here we expand on the possible interactions between AKIN10, whose activity is involved in transcriptional reprogramming, and clock elements GI and TIC. We hypothesize how they could participate in clock entrainment through a metabolic signal derived from carbon pools and starch metabolism. Additionally, we consider further the role of cellular energy status to the clock through the formation of a hypothetical protein complex. We also demonstrate the role of AKIN10, but not its sequence-related kinase AKIN11, on clock periodicity. Altogether we present a model of action of these elements in metabolic-related clock entrainment.
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Affiliation(s)
- Alfredo Sánchez-Villarreal
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
- Colegio de Postgraduados campus Campeche, Campeche, Mexico
| | - Amanda M. Davis
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
- Department of Biology, University of York, York, UK
| | - Seth J. Davis
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
- Department of Biology, University of York, York, UK
- CONTACT Seth J. Davis Department of Biology, University of York and Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research
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Pedrotti L, Weiste C, Nägele T, Wolf E, Lorenzin F, Dietrich K, Mair A, Weckwerth W, Teige M, Baena-González E, Dröge-Laser W. Snf1-RELATED KINASE1-Controlled C/S 1-bZIP Signaling Activates Alternative Mitochondrial Metabolic Pathways to Ensure Plant Survival in Extended Darkness. THE PLANT CELL 2018; 30:495-509. [PMID: 29348240 PMCID: PMC5868691 DOI: 10.1105/tpc.17.00414] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 11/30/2017] [Accepted: 01/16/2018] [Indexed: 05/18/2023]
Abstract
Sustaining energy homeostasis is of pivotal importance for all living organisms. In Arabidopsis thaliana, evolutionarily conserved SnRK1 kinases (Snf1-RELATED KINASE1) control metabolic adaptation during low energy stress. To unravel starvation-induced transcriptional mechanisms, we performed transcriptome studies of inducible knockdown lines and found that S1-basic leucine zipper transcription factors (S1-bZIPs) control a defined subset of genes downstream of SnRK1. For example, S1-bZIPs coordinate the expression of genes involved in branched-chain amino acid catabolism, which constitutes an alternative mitochondrial respiratory pathway that is crucial for plant survival during starvation. Molecular analyses defined S1-bZIPs as SnRK1-dependent regulators that directly control transcription via binding to G-box promoter elements. Moreover, SnRK1 triggers phosphorylation of group C-bZIPs and the formation of C/S1-heterodimers and, thus, the recruitment of SnRK1 directly to target promoters. Subsequently, the C/S1-bZIP-SnRK1 complex interacts with the histone acetylation machinery to remodel chromatin and facilitate transcription. Taken together, this work reveals molecular mechanisms underlying how energy deprivation is transduced to reprogram gene expression, leading to metabolic adaptation upon stress.
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Affiliation(s)
- Lorenzo Pedrotti
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institute, Biocenter, Julius-Maximilians-Universität Würzburg, Würzburg 97082, Germany
| | - Christoph Weiste
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institute, Biocenter, Julius-Maximilians-Universität Würzburg, Würzburg 97082, Germany
| | - Thomas Nägele
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna 1090, Austria
- Vienna Metabolomics Center, University of Vienna, Vienna 1090, Austria
| | - Elmar Wolf
- Department of Biochemistry and Molecular Biology, Theodor-Boveri-Institute, Biocenter, Julius-Maximilians-Universität Würzburg, Würzburg 97074, Germany
| | - Francesca Lorenzin
- Department of Biochemistry and Molecular Biology, Theodor-Boveri-Institute, Biocenter, Julius-Maximilians-Universität Würzburg, Würzburg 97074, Germany
| | - Katrin Dietrich
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institute, Biocenter, Julius-Maximilians-Universität Würzburg, Würzburg 97082, Germany
| | - Andrea Mair
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna 1090, Austria
| | - Wolfram Weckwerth
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna 1090, Austria
- Vienna Metabolomics Center, University of Vienna, Vienna 1090, Austria
| | - Markus Teige
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna 1090, Austria
| | | | - Wolfgang Dröge-Laser
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institute, Biocenter, Julius-Maximilians-Universität Würzburg, Würzburg 97082, Germany
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34
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Pu Y, Soto-Burgos J, Bassham DC. Regulation of autophagy through SnRK1 and TOR signaling pathways. PLANT SIGNALING & BEHAVIOR 2017; 12:e1395128. [PMID: 29058995 PMCID: PMC5792129 DOI: 10.1080/15592324.2017.1395128] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 10/17/2017] [Indexed: 05/20/2023]
Abstract
Autophagy is important for degradation and recycling of cytoplasmic materials in all eukaryotes and is often triggered by environmental stress. How autophagy is activated in plants under different environmental conditions is still poorly understood. Our recent studies show that induction of autophagy by different abiotic stress conditions can occur via either a TOR-dependent or -independent pathway, depending on the stress. The SnRK1 protein kinase complex acts upstream of TOR in regulation of autophagy during nutrient deficiency, salt and osmotic stresses. In contrast, oxidative and ER stress regulate autophagy in a SnRK1-dependent but TOR-independent manner. Here we summarize and discuss these distinct pathways for activation of autophagy under different environmental stress conditions.
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Affiliation(s)
- Yunting Pu
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Junmarie Soto-Burgos
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Diane C. Bassham
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
- CONTACT Diane C. Bassham Department of Genetics, Development and Cell Biology, 1035B Roy J. Carver Co-Laboratory, 1111 WOI Road, Iowa State University, Ames, Iowa 50011-3650, USA
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35
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Zhai Z, Liu H, Xu C, Shanklin J. Sugar Potentiation of Fatty Acid and Triacylglycerol Accumulation. PLANT PHYSIOLOGY 2017; 175:696-707. [PMID: 28842550 PMCID: PMC5619906 DOI: 10.1104/pp.17.00828] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 08/22/2017] [Indexed: 05/19/2023]
Abstract
Photosynthetically derived sugar provides carbon skeletons for lipid biosynthesis. We used mutants of Arabidopsis (Arabidopsis thaliana) and the expression of oleogenic factors to investigate relationships among sugar availability, lipid synthesis, and the accumulation of triacylglycerol (TAG) in leaf tissue. The adg1 mutation disables the small subunit of ADP-glucose pyrophosphorylase, the first step in starch synthesis, and the suc2 mutation disables a sucrose/proton symporter that facilitates sucrose loading from leaves into phloem. The adg1suc2 double mutant increases glucose plus sucrose content in leaves 80-fold relative to the wild type, total fatty acid (FA) content 1.8-fold to 8.3% dry weight, and TAG more than 10-fold to 1.2% dry weight. The WRINKLED1 transcription factor also accumulates to higher levels in these leaves, and the rate of FA synthesis increases by 58%. Adding tt4, which disables chalcone synthase, had little effect, but adding the tgd1 mutation, which disables an importer of lipids into plastids to create adg1suc2tt4tgd1, increased total leaf FA to 13.5% dry weight and TAG to 3.8% dry weight, demonstrating a synergistic effect upon combining these mutations. Combining adg1suc2 with the sdp1 mutation, deficient in the predominant TAG lipase, had little effect on total FA content but increased the TAG accumulation by 66% to 2% dry weight. Expression of the WRINKLED1 transcription factor, along with DIACYLGLYCEROL ACYLTRANSFERASE1 and the OLEOSIN1 oil body-associated protein, in the adg1suc2 mutant doubled leaf FA content and increased TAG content to 2.3% dry weight, a level 4.6-fold higher than that resulting from expression of the same factors in the wild type.
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Affiliation(s)
- Zhiyang Zhai
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Hui Liu
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Changcheng Xu
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - John Shanklin
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
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36
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Otori K, Tanabe N, Maruyama T, Sato S, Yanagisawa S, Tamoi M, Shigeoka S. Enhanced photosynthetic capacity increases nitrogen metabolism through the coordinated regulation of carbon and nitrogen assimilation in Arabidopsis thaliana. JOURNAL OF PLANT RESEARCH 2017; 130:909-927. [PMID: 28470336 DOI: 10.1007/s10265-017-0950-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/12/2017] [Indexed: 06/07/2023]
Abstract
Plant growth and productivity depend on interactions between the metabolism of carbon and nitrogen. The sensing ability of internal carbon and nitrogen metabolites (the C/N balance) enables plants to regulate metabolism and development. In order to investigate the effects of an enhanced photosynthetic capacity on the metabolism of carbon and nitrogen in photosynthetically active tissus (source leaves), we herein generated transgenic Arabidopsis thaliana plants (ApFS) that expressed cyanobacterial fructose-1,6-/sedoheptulose-1,7-bisphosphatase in their chloroplasts. The phenotype of ApFS plants was indistinguishable from that of wild-type plants at the immature stage. However, as plants matured, the growth of ApFS plants was superior to that of wild-type plants. Starch levels were higher in ApFS plants than in wild-type plants at 2 and 5 weeks. Sucrose levels were also higher in ApFS plants than in wild-type plants, but only at 5 weeks. On the other hand, the contents of various free amino acids were lower in ApFS plants than in wild-type plants at 2 weeks, but were similar at 5 weeks. The total C/N ratio was the same in ApFS plants and wild-type plants, whereas nitrite levels increased in parallel with elevations in nitrate reductase activity at 5 weeks in ApFS plants. These results suggest that increases in the contents of photosynthetic intermediates at the early growth stage caused a temporary imbalance in the free-C/free-N ratio and, thus, the feedback inhibition of the expression of genes involved in the Calvin cycle and induction of the expression of those involved in nitrogen metabolism due to supply deficient free amino acids for maintenance of the C/N balance in source leaves of ApFS plants.
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Affiliation(s)
- Kumi Otori
- Department of Advanced Bioscience, Faculty of Agriculture, Kindai University, Nakamachi, Nara, 631-8505, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Kawaguchi, 332-0012, Japan
| | - Noriaki Tanabe
- Department of Advanced Bioscience, Faculty of Agriculture, Kindai University, Nakamachi, Nara, 631-8505, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Kawaguchi, 332-0012, Japan
| | - Toshiki Maruyama
- Department of Advanced Bioscience, Faculty of Agriculture, Kindai University, Nakamachi, Nara, 631-8505, Japan
| | - Shigeru Sato
- Biotechnology Research Center, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Shuichi Yanagisawa
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Kawaguchi, 332-0012, Japan
- Biotechnology Research Center, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Masahiro Tamoi
- Department of Advanced Bioscience, Faculty of Agriculture, Kindai University, Nakamachi, Nara, 631-8505, Japan.
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Kawaguchi, 332-0012, Japan.
| | - Shigeru Shigeoka
- Department of Advanced Bioscience, Faculty of Agriculture, Kindai University, Nakamachi, Nara, 631-8505, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Kawaguchi, 332-0012, Japan
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37
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Soto-Burgos J, Bassham DC. SnRK1 activates autophagy via the TOR signaling pathway in Arabidopsis thaliana. PLoS One 2017; 12:e0182591. [PMID: 28783755 PMCID: PMC5544219 DOI: 10.1371/journal.pone.0182591] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 07/20/2017] [Indexed: 12/26/2022] Open
Abstract
Autophagy is a degradation process in which cells break down and recycle their cytoplasmic contents when subjected to environmental stress or during cellular remodeling. The Arabidopsis thaliana SnRK1 complex is a protein kinase that senses changes in energy levels and triggers downstream responses to enable survival. Its mammalian ortholog, AMPK, and yeast ortholog, Snf-1, activate autophagy in response to low energy conditions. We therefore hypothesized that SnRK1 may play a role in the regulation of autophagy in response to nutrient or energy deficiency in Arabidopsis. To test this hypothesis, we determined the effect of overexpression or knockout of the SnRK1 catalytic subunit KIN10 on autophagy activation by abiotic stresses, including nutrient deficiency, salt, osmotic, oxidative, and ER stress. While wild-type plants had low basal autophagy activity in control conditions, KIN10 overexpression lines had increased autophagy under these conditions, indicating activation of autophagy by SnRK1. A kin10 mutant had a basal level of autophagy under control conditions similar to wild-type plants, but activation of autophagy by most abiotic stresses was blocked, indicating that SnRK1 is required for autophagy induction by a wide variety of stress conditions. In mammals, TOR is a negative regulator of autophagy, and AMPK acts to activate autophagy both upstream of TOR, by inhibiting its activity, and in a parallel pathway. Inhibition of Arabidopsis TOR leads to activation of autophagy; inhibition of SnRK1 did not block this activation. Furthermore, an increase in SnRK1 activity was unable to induce autophagy when TOR was also activated. These results demonstrate that SnRK1 acts upstream of TOR in the activation of autophagy in Arabidopsis.
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Affiliation(s)
- Junmarie Soto-Burgos
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Diane C. Bassham
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
- Plant Sciences Institute, Iowa State University, Ames, Iowa, United States of America
- * E-mail:
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38
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Miller MAE, O’Cualain R, Selley J, Knight D, Karim MF, Hubbard SJ, Johnson GN. Dynamic Acclimation to High Light in Arabidopsis thaliana Involves Widespread Reengineering of the Leaf Proteome. FRONTIERS IN PLANT SCIENCE 2017; 8:1239. [PMID: 28775726 PMCID: PMC5517461 DOI: 10.3389/fpls.2017.01239] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 06/30/2017] [Indexed: 05/18/2023]
Abstract
Leaves of Arabidopsis thaliana transferred from low to high light increase their capacity for photosynthesis, a process of dynamic acclimation. A mutant, gpt2, lacking a chloroplast glucose-6-phosphate/phosphate translocator, is deficient in its ability to acclimate to increased light. Here, we have used a label-free proteomics approach, to perform relative quantitation of 1993 proteins from Arabidopsis wild type and gpt2 leaves exposed to increased light. Data are available via ProteomeXchange with identifier PXD006598. Acclimation to light is shown to involve increases in electron transport and carbon metabolism but no change in the abundance of photosynthetic reaction centers. The gpt2 mutant shows a similar increase in total protein content to wild type but differences in the extent of change of certain proteins, including in the relative abundance of the cytochrome b6f complex and plastocyanin, the thylakoid ATPase and selected Benson-Calvin cycle enzymes. Changes in leaf metabolite content as plants acclimate can be explained by changes in the abundance of enzymes involved in metabolism, which were reduced in gpt2 in some cases. Plants of gpt2 invest more in stress-related proteins, suggesting that their reduced ability to acclimate photosynthetic capacity results in increased stress.
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Affiliation(s)
- Matthew A. E. Miller
- School of Earth and Environmental Sciences, University of ManchesterManchester, United Kingdom
| | - Ronan O’Cualain
- School of Biological Sciences, University of ManchesterManchester, United Kingdom
| | - Julian Selley
- School of Biological Sciences, University of ManchesterManchester, United Kingdom
| | - David Knight
- School of Biological Sciences, University of ManchesterManchester, United Kingdom
| | - Mohd F. Karim
- School of Earth and Environmental Sciences, University of ManchesterManchester, United Kingdom
| | - Simon J. Hubbard
- School of Biological Sciences, University of ManchesterManchester, United Kingdom
| | - Giles N. Johnson
- School of Earth and Environmental Sciences, University of ManchesterManchester, United Kingdom
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Shin J, Sánchez-Villarreal A, Davis AM, Du SX, Berendzen KW, Koncz C, Ding Z, Li C, Davis SJ. The metabolic sensor AKIN10 modulates the Arabidopsis circadian clock in a light-dependent manner. PLANT, CELL & ENVIRONMENT 2017; 40:997-1008. [PMID: 28054361 DOI: 10.1111/pce.12903] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 12/12/2016] [Accepted: 12/19/2016] [Indexed: 05/06/2023]
Abstract
Plants generate rhythmic metabolism during the repetitive day/night cycle. The circadian clock produces internal biological rhythms to synchronize numerous metabolic processes such that they occur at the required time of day. Metabolism conversely influences clock function by controlling circadian period and phase and the expression of core-clock genes. Here, we show that AKIN10, a catalytic subunit of the evolutionarily conserved key energy sensor sucrose non-fermenting 1 (Snf1)-related kinase 1 (SnRK1) complex, plays an important role in the circadian clock. Elevated AKIN10 expression led to delayed peak expression of the circadian clock evening-element GIGANTEA (GI) under diurnal conditions. Moreover, it lengthened clock period specifically under light conditions. Genetic analysis showed that the clock regulator TIME FOR COFFEE (TIC) is required for this effect of AKIN10. Taken together, we propose that AKIN10 conditionally works in a circadian clock input pathway to the circadian oscillator.
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Affiliation(s)
- Jieun Shin
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
| | - Alfredo Sánchez-Villarreal
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
- Colegio de Postgraduados campus Campeche, Campeche, 24750, Mexico
| | - Amanda M Davis
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
- Department of Biology, University of York, York, YO10 5DD, UK
| | - Shen-Xiu Du
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
| | - Kenneth W Berendzen
- Zentrum für Molekularbiologie der Pflanzen, Universität Tübingen, Tübingen, 72076, Germany
| | - Csaba Koncz
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
| | - Zhaojun Ding
- College of Life Sciences, Shandong University, Jinan, 250100, China
| | - Cuiling Li
- College of Life Sciences, Shandong University, Jinan, 250100, China
| | - Seth J Davis
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
- Department of Biology, University of York, York, YO10 5DD, UK
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40
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Zhai Z, Liu H, Shanklin J. Phosphorylation of WRINKLED1 by KIN10 Results in Its Proteasomal Degradation, Providing a Link between Energy Homeostasis and Lipid Biosynthesis. THE PLANT CELL 2017; 29:871-889. [PMID: 28314829 PMCID: PMC5435435 DOI: 10.1105/tpc.17.00019] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 02/26/2017] [Accepted: 03/16/2017] [Indexed: 05/18/2023]
Abstract
WRINKLED1 (WRI1), a member of the APETALA2 (AP2) class of transcription factors, positively regulates glycolysis and lipid biosynthesis in Arabidopsis thaliana Here, we identify mechanistic links between KIN10, the major SUCROSE NON-FERMENTATION1-RELATED KINASE1 involved in sugar/energy homeostasis, and the posttranslational regulation of WRI1. Transient expression of WRI1 with OLEOSIN1 in Nicotiana benthamiana stimulates triacylglycerol accumulation, but their coexpression with KIN10 abrogates this effect by inducing proteasomal degradation of WRI1. While WRI1 lacks canonical KIN10 target sequences, we demonstrated direct KIN10-dependent phosphorylation of WRI1 using purified Escherichia coli-expressed components. The resulting phosphorylated WRI1 was more rapidly degraded than native WRI1 in cell-free degradation assays. WRI1 phosphorylation was localized to two variants of the canonical KIN10 recognition sequence, one in each of its two AP2 DNA binding domains. Conversion of the phosphorylation sites at Thr-70 and Ser-166 to Ala resulted in a loss of KIN10-dependent phosphorylation, and when coexpressed with KIN10 the WRI1 double mutant accumulated to 2- to 3-fold higher levels than native WRI1. KIN10-dependent degradation of WRI1 provides a homeostatic mechanism that favors lipid biosynthesis when intracellular sugar levels are elevated and KIN10 is inhibited; conversely, glycolysis and lipid biosynthesis are curtailed as sugar levels decrease and KIN10 regains activity.
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Affiliation(s)
- Zhiyang Zhai
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Hui Liu
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - John Shanklin
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
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41
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Baena-González E, Hanson J. Shaping plant development through the SnRK1-TOR metabolic regulators. CURRENT OPINION IN PLANT BIOLOGY 2017; 35:152-157. [PMID: 28027512 DOI: 10.1016/j.pbi.2016.12.004] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/05/2016] [Accepted: 12/07/2016] [Indexed: 05/20/2023]
Abstract
SnRK1 (Snf1-related protein kinase 1) and TOR (target of rapamycin) are evolutionarily conserved protein kinases that lie at the heart of energy sensing, playing central and antagonistic roles in the regulation of metabolism and gene expression. Increasing evidence links these metabolic regulators to numerous aspects of plant development, from germination to flowering and senescence. This prompts the hypothesis that SnRK1 and TOR modify developmental programs according to the metabolic status to adjust plant growth to a specific environment. The aim of this review is to provide support to this hypothesis and to incentivize further studies on this topic by summarizing the work that establishes a genetic connection between SnRK1-TOR and plant development.
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Affiliation(s)
- Elena Baena-González
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.
| | - Johannes Hanson
- Umeå Plant Science Center, Department of Plant Physiology, Umeå University, 90187 Umeå, Sweden.
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42
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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: 138] [Impact Index Per Article: 17.3] [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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Li L, Sheen J. Dynamic and diverse sugar signaling. CURRENT OPINION IN PLANT BIOLOGY 2016; 33:116-125. [PMID: 27423125 PMCID: PMC5050104 DOI: 10.1016/j.pbi.2016.06.018] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Revised: 06/17/2016] [Accepted: 06/27/2016] [Indexed: 05/18/2023]
Abstract
Sugars fuel life and exert numerous regulatory actions that are fundamental to all life forms. There are two principal mechanisms underlie sugar 'perception and signal transduction' in biological systems. Direct sensing and signaling is triggered via sugar-binding sensors with a broad range of affinity and specificity, whereas sugar-derived bioenergetic molecules and metabolites modulate signaling proteins and indirectly relay sugar signals. This review discusses the emerging sugar signals and potential sugar sensors discovered in plant systems. The findings leading to informative understanding of physiological regulation by sugars are considered and assessed. Comparative transcriptome analyses highlight the primary and dynamic sugar responses and reveal the convergent and specific regulators of key biological processes in the sugar-signaling network.
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Affiliation(s)
- Lei Li
- Department of Genetics, Harvard Medical School, USA; Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, MA 02114, USA
| | - Jen Sheen
- Department of Genetics, Harvard Medical School, USA; Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, MA 02114, USA.
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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: 53] [Impact Index Per Article: 6.6] [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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Perochon A, Jianguang J, Kahla A, Arunachalam C, Scofield SR, Bowden S, Wallington E, Doohan FM. TaFROG Encodes a Pooideae Orphan Protein That Interacts with SnRK1 and Enhances Resistance to the Mycotoxigenic Fungus Fusarium graminearum. PLANT PHYSIOLOGY 2015; 169:2895-906. [PMID: 26508775 PMCID: PMC4677899 DOI: 10.1104/pp.15.01056] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/26/2015] [Indexed: 05/18/2023]
Abstract
All genomes encode taxonomically restricted orphan genes, and the vast majority are of unknown function. There is growing evidence that such genes play an important role in the environmental adaptation of taxa. We report the functional characterization of an orphan gene (Triticum aestivum Fusarium Resistance Orphan Gene [TaFROG]) as a component of resistance to the globally important wheat (T. aestivum) disease, Fusarium head blight. TaFROG is taxonomically restricted to the grass subfamily Pooideae. Gene expression studies showed that it is a component of the early wheat response to the mycotoxin deoxynivalenol (DON), which is a virulence factor produced by the causal fungal agent of Fusarium head blight, Fusarium graminearum. The temporal induction of TaFROG by F. graminearum in wheat spikelets correlated with the activation of the defense Triticum aestivum Pathogenesis-Related-1 (TaPR1) gene. But unlike TaPR1, TaFROG induction by F. graminearum was toxin dependent, as determined via comparative analysis of the effects of wild-type fungus and a DON minus mutant derivative. Using virus-induced gene silencing and overexpressing transgenic wheat lines, we present evidence that TaFROG contributes to host resistance to both DON and F. graminearum. TaFROG is an intrinsically disordered protein, and it localized to the nucleus. A wheat alpha subunit of the Sucrose Non-Fermenting1-Related Kinase1 was identified as a TaFROG-interacting protein based on a yeast two-hybrid study. In planta bimolecular fluorescence complementation assays confirmed the interaction. Thus, we conclude that TaFROG encodes a new Sucrose Non-Fermenting1-Related Kinase1-interacting protein and enhances biotic stress resistance.
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Affiliation(s)
- Alexandre Perochon
- University College Dublin Earth Institute and School of Biology and Environmental Science, College of Science, University College Dublin, Belfield, Dublin 4, Ireland (A.P., J.J., A.K., C.A., F.M.D.);United States Department of Agriculture, Agricultural Research Service, Crop Production and Pest Control Research Unit, and Purdue University, Department of Agronomy, West Lafayette, Indiana 47907-2054 (S.R.S.); andNational Institute of Agricultural Botany, Cambridge, CB3 0LE, United Kingdom (S.B., E.W.)
| | - Jia Jianguang
- University College Dublin Earth Institute and School of Biology and Environmental Science, College of Science, University College Dublin, Belfield, Dublin 4, Ireland (A.P., J.J., A.K., C.A., F.M.D.);United States Department of Agriculture, Agricultural Research Service, Crop Production and Pest Control Research Unit, and Purdue University, Department of Agronomy, West Lafayette, Indiana 47907-2054 (S.R.S.); andNational Institute of Agricultural Botany, Cambridge, CB3 0LE, United Kingdom (S.B., E.W.)
| | - Amal Kahla
- University College Dublin Earth Institute and School of Biology and Environmental Science, College of Science, University College Dublin, Belfield, Dublin 4, Ireland (A.P., J.J., A.K., C.A., F.M.D.);United States Department of Agriculture, Agricultural Research Service, Crop Production and Pest Control Research Unit, and Purdue University, Department of Agronomy, West Lafayette, Indiana 47907-2054 (S.R.S.); andNational Institute of Agricultural Botany, Cambridge, CB3 0LE, United Kingdom (S.B., E.W.)
| | - Chanemougasoundharam Arunachalam
- University College Dublin Earth Institute and School of Biology and Environmental Science, College of Science, University College Dublin, Belfield, Dublin 4, Ireland (A.P., J.J., A.K., C.A., F.M.D.);United States Department of Agriculture, Agricultural Research Service, Crop Production and Pest Control Research Unit, and Purdue University, Department of Agronomy, West Lafayette, Indiana 47907-2054 (S.R.S.); andNational Institute of Agricultural Botany, Cambridge, CB3 0LE, United Kingdom (S.B., E.W.)
| | - Steven R Scofield
- University College Dublin Earth Institute and School of Biology and Environmental Science, College of Science, University College Dublin, Belfield, Dublin 4, Ireland (A.P., J.J., A.K., C.A., F.M.D.);United States Department of Agriculture, Agricultural Research Service, Crop Production and Pest Control Research Unit, and Purdue University, Department of Agronomy, West Lafayette, Indiana 47907-2054 (S.R.S.); andNational Institute of Agricultural Botany, Cambridge, CB3 0LE, United Kingdom (S.B., E.W.)
| | - Sarah Bowden
- University College Dublin Earth Institute and School of Biology and Environmental Science, College of Science, University College Dublin, Belfield, Dublin 4, Ireland (A.P., J.J., A.K., C.A., F.M.D.);United States Department of Agriculture, Agricultural Research Service, Crop Production and Pest Control Research Unit, and Purdue University, Department of Agronomy, West Lafayette, Indiana 47907-2054 (S.R.S.); andNational Institute of Agricultural Botany, Cambridge, CB3 0LE, United Kingdom (S.B., E.W.)
| | - Emma Wallington
- University College Dublin Earth Institute and School of Biology and Environmental Science, College of Science, University College Dublin, Belfield, Dublin 4, Ireland (A.P., J.J., A.K., C.A., F.M.D.);United States Department of Agriculture, Agricultural Research Service, Crop Production and Pest Control Research Unit, and Purdue University, Department of Agronomy, West Lafayette, Indiana 47907-2054 (S.R.S.); andNational Institute of Agricultural Botany, Cambridge, CB3 0LE, United Kingdom (S.B., E.W.)
| | - Fiona M Doohan
- University College Dublin Earth Institute and School of Biology and Environmental Science, College of Science, University College Dublin, Belfield, Dublin 4, Ireland (A.P., J.J., A.K., C.A., F.M.D.);United States Department of Agriculture, Agricultural Research Service, Crop Production and Pest Control Research Unit, and Purdue University, Department of Agronomy, West Lafayette, Indiana 47907-2054 (S.R.S.); andNational Institute of Agricultural Botany, Cambridge, CB3 0LE, United Kingdom (S.B., E.W.)
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Lin Y, Liu T, Liu J, Liu X, Ou Y, Zhang H, Li M, Sonnewald U, Song B, Xie C. Subtle Regulation of Potato Acid Invertase Activity by a Protein Complex of Invertase, Invertase Inhibitor, and SUCROSE NONFERMENTING1-RELATED PROTEIN KINASE. PLANT PHYSIOLOGY 2015; 168:1807-19. [PMID: 26134163 PMCID: PMC4528764 DOI: 10.1104/pp.15.00664] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 06/25/2015] [Indexed: 05/19/2023]
Abstract
Slowing down cold-induced sweetening (CIS) of potato (Solanum tuberosum) tubers is of economic importance for the potato industry to ensure high-quality products. The conversion of sucrose to reducing sugars by the acid invertase StvacINV1 is thought to be critical for CIS. Identification of the specific StvacINV1 inhibitor StInvInh2B and the α- and β-subunits of the interacting protein SUCROSE NONFERMENTING1-RELATED PROTEIN KINASE from the wild potato species Solanum berthaultii (SbSnRK1) has led to speculation that invertase activity may be regulated via a posttranslational mechanism that remains to be elucidated. Using bimolecular fluorescence complementation assays, this study confirmed the protein complex by pairwise interactions. In vitro kinase assays and protein phosphorylation analysis revealed that phosphorylation of SbSnRK1α is causal for StvacINV1 activity and that its active form blocks the inhibition of StInvInh2B by SbSnRK1β, whereas its inactive form restores the function of SbSnRK1β that prevents StInvInh2B from repressing StvacINV1. Overexpression of SbSnRK1α in CIS-sensitive potato confirmed that SbSnRK1α has significant effects on acid invertase-associated sucrose degradation. A higher level of SbSnRK1α expression was accompanied by elevated SbSnRK1α phosphorylation, reduced acid invertase activity, a higher sucrose-hexose ratio, and improved chip color. Our results lend new insights into a subtle regulatory mode of invertase activity and provide a novel approach for potato CIS improvement.
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Affiliation(s)
- Yuan Lin
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, National Center for Vegetable Improvement (Central China), Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.L., T.L., J.L., X.L., Y.O., H.Z., M.L., B.S., C.X.); andBiochemistry Division, Department of Biology, Friedrich-Alexander-University Erlangen-Nuernberg, 91058 Erlangen, Germany (U.S.)
| | - Tengfei Liu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, National Center for Vegetable Improvement (Central China), Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.L., T.L., J.L., X.L., Y.O., H.Z., M.L., B.S., C.X.); andBiochemistry Division, Department of Biology, Friedrich-Alexander-University Erlangen-Nuernberg, 91058 Erlangen, Germany (U.S.)
| | - Jun Liu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, National Center for Vegetable Improvement (Central China), Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.L., T.L., J.L., X.L., Y.O., H.Z., M.L., B.S., C.X.); andBiochemistry Division, Department of Biology, Friedrich-Alexander-University Erlangen-Nuernberg, 91058 Erlangen, Germany (U.S.)
| | - Xun Liu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, National Center for Vegetable Improvement (Central China), Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.L., T.L., J.L., X.L., Y.O., H.Z., M.L., B.S., C.X.); andBiochemistry Division, Department of Biology, Friedrich-Alexander-University Erlangen-Nuernberg, 91058 Erlangen, Germany (U.S.)
| | - Yongbin Ou
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, National Center for Vegetable Improvement (Central China), Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.L., T.L., J.L., X.L., Y.O., H.Z., M.L., B.S., C.X.); andBiochemistry Division, Department of Biology, Friedrich-Alexander-University Erlangen-Nuernberg, 91058 Erlangen, Germany (U.S.)
| | - Huiling Zhang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, National Center for Vegetable Improvement (Central China), Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.L., T.L., J.L., X.L., Y.O., H.Z., M.L., B.S., C.X.); andBiochemistry Division, Department of Biology, Friedrich-Alexander-University Erlangen-Nuernberg, 91058 Erlangen, Germany (U.S.)
| | - Meng Li
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, National Center for Vegetable Improvement (Central China), Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.L., T.L., J.L., X.L., Y.O., H.Z., M.L., B.S., C.X.); andBiochemistry Division, Department of Biology, Friedrich-Alexander-University Erlangen-Nuernberg, 91058 Erlangen, Germany (U.S.)
| | - Uwe Sonnewald
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, National Center for Vegetable Improvement (Central China), Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.L., T.L., J.L., X.L., Y.O., H.Z., M.L., B.S., C.X.); andBiochemistry Division, Department of Biology, Friedrich-Alexander-University Erlangen-Nuernberg, 91058 Erlangen, Germany (U.S.)
| | - Botao Song
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, National Center for Vegetable Improvement (Central China), Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.L., T.L., J.L., X.L., Y.O., H.Z., M.L., B.S., C.X.); andBiochemistry Division, Department of Biology, Friedrich-Alexander-University Erlangen-Nuernberg, 91058 Erlangen, Germany (U.S.)
| | - Conghua Xie
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, National Center for Vegetable Improvement (Central China), Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.L., T.L., J.L., X.L., Y.O., H.Z., M.L., B.S., C.X.); andBiochemistry Division, Department of Biology, Friedrich-Alexander-University Erlangen-Nuernberg, 91058 Erlangen, Germany (U.S.)
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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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