101
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Transcriptional and Epigenetic Regulation of Autophagy in Plants. Trends Genet 2020; 36:676-688. [PMID: 32674948 DOI: 10.1016/j.tig.2020.06.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/19/2020] [Accepted: 06/22/2020] [Indexed: 01/12/2023]
Abstract
Autophagy, a highly conserved quality control mechanism, is essential for maintaining cellular homeostasis and healthy growth of plants. Compared with extensive research in the cytoplasmic control of autophagy, studies regarding the nuclear events involved in the regulation of plant autophagy are just beginning to emerge. Accumulating evidence reveals a coordinated expression of plant autophagy genes in response to diverse developmental states and growth conditions. Here, we summarize recent progress in the identification of tightly controlled transcription factors and histone marks associated with the autophagic process in plants, and propose several modules, consisting of transcription regulators and epigenetic modifiers, as important nuclear players that could contribute to both short-term and long-term controls of plant autophagy at the transcriptional and post-transcriptional levels.
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102
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Zhuo F, Xiong F, Deng K, Li Z, Ren M. Target of Rapamycin (TOR) Negatively Regulates Ethylene Signals in Arabidopsis. Int J Mol Sci 2020; 21:E2680. [PMID: 32290539 PMCID: PMC7215648 DOI: 10.3390/ijms21082680] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/07/2020] [Accepted: 04/10/2020] [Indexed: 12/12/2022] Open
Abstract
Target of rapamycin (TOR) acts as a master regulator in coordination of cell growth with energy and nutrient availability. Despite the increased appreciation of the essential role of the TOR complex in interaction with phytohormone signaling, little is known about its function on ethylene signaling. Here, through expression analysis, genetic and biochemical approaches, we reveal that TOR functions in the regulation of ethylene signals. Transcriptional analysis indicates that TOR inhibition by AZD8055 upregulated senescence- and ethylene-related genes expression. Furthermore, ethylene insensitive mutants like etr1-1, ein2-5 and ein3 eil1, showed more hyposensitivity to AZD8055 than that of WT in hypocotyl growth inhibition. Similarly, blocking ethylene signals by ethylene action inhibitor Ag+ or biosynthesis inhibitor aminoethoxyvinylglycine (AVG) largely rescued hypocotyl growth even in presence of AZD8055. In addition, we also demonstrated that Type 2A phosphatase-associated protein of 46 kDa (TAP46), a downstream component of TOR signaling, physically interacts with 1-aminocy-clopropane-1-carboxylate (ACC) synthase ACS2 and ACS6. Arabidopsis overexpressing ACS2 or ACS6 showed more hypersensitivity to AZD8055 than WT in hypocotyl growth inhibition. Moreover, ACS2/ACS6 protein was accumulated under TOR suppression, implying TOR modulates ACC synthase protein levels. Taken together, our results indicate that TOR participates in negatively modulating ethylene signals and the molecular mechanism is likely involved in the regulation of ethylene biosynthesis by affecting ACSs in transcription and protein levels.
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Affiliation(s)
- Fengping Zhuo
- School of Life Sciences, Chongqing University, Chongqing 401331, China; (F.Z.); (F.X.); (K.D.)
- School of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Fangjie Xiong
- School of Life Sciences, Chongqing University, Chongqing 401331, China; (F.Z.); (F.X.); (K.D.)
| | - Kexuan Deng
- School of Life Sciences, Chongqing University, Chongqing 401331, China; (F.Z.); (F.X.); (K.D.)
| | - Zhengguo Li
- School of Life Sciences, Chongqing University, Chongqing 401331, China; (F.Z.); (F.X.); (K.D.)
| | - Maozhi Ren
- School of Life Sciences, Chongqing University, Chongqing 401331, China; (F.Z.); (F.X.); (K.D.)
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou 455001, China
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610000, China
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103
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Fu L, Wang P, Xiong Y. Target of Rapamycin Signaling in Plant Stress Responses. PLANT PHYSIOLOGY 2020; 182:1613-1623. [PMID: 31949028 PMCID: PMC7140942 DOI: 10.1104/pp.19.01214] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 12/21/2019] [Indexed: 05/05/2023]
Abstract
Target of Rapamycin (TOR) is an atypical Ser/Thr protein kinase that is evolutionally conserved among yeasts, plants, and mammals. In plants, TOR signaling functions as a central hub to integrate different kinds of nutrient, energy, hormone, and environmental signals. TOR thereby orchestrates every stage of plant life, from embryogenesis, meristem activation, root, and leaf growth to flowering, senescence, and life span determination. Besides its essential role in the control of plant growth and development, recent research has also shed light on its multifaceted roles in plant environmental stress responses. Here, we review recent findings on the involvement of TOR signaling in plant adaptation to nutrient deficiency and various abiotic stresses. We also discuss the mechanisms underlying how plants cope with such unfavorable conditions via TOR-abscisic acid crosstalk and TOR-mediated autophagy, both of which play crucial roles in plant stress responses. Until now, little was known about the upstream regulators and downstream effectors of TOR in plant stress responses. We propose that the Snf1-related protein kinase-TOR axis plays a role in sensing various stress signals, and predict the key downstream effectors based on recent high-throughput proteomic analyses.
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Affiliation(s)
- Liwen Fu
- Basic Forestry and Proteomics Research Centre, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fujian Province 350002, People's Republic of China
| | - Pengcheng Wang
- Shanghai Centre for Plant Stress Biology, Chinese Academy of Sciences Centre for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, People's Republic of China
| | - Yan Xiong
- Basic Forestry and Proteomics Research Centre, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fujian Province 350002, People's Republic of China
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104
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Liao CY, Bassham DC. Combating stress: the interplay between hormone signaling and autophagy in plants. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:1723-1733. [PMID: 31725881 PMCID: PMC7067298 DOI: 10.1093/jxb/erz515] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 11/13/2019] [Indexed: 05/18/2023]
Abstract
Autophagy is a conserved recycling process in which cellular components are delivered to and degraded in the vacuole/lysosome for reuse. In plants, it assists in responding to dynamic environmental conditions and maintaining metabolite homeostasis under normal or stress conditions. Under stress, autophagy is activated to remove damaged components and to recycle nutrients for survival, and the energy sensor kinases target of rapamycin (TOR) and SNF-related kinase 1 (SnRK1) are key to this activation. Here, we discuss accumulating evidence that hormone signaling plays critical roles in regulating autophagy and plant stress responses, although the molecular mechanisms by which this occurs are often not clear. Several hormones have been shown to regulate TOR activity during stress, in turn controlling autophagy. Hormone signaling can also regulate autophagy gene expression, while, reciprocally, autophagy can regulate hormone synthesis and signaling pathways. We highlight how the interplay between major energy sensors, plant hormones, and autophagy under abiotic and biotic stress conditions can assist in plant stress tolerance.
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Affiliation(s)
- Ching-Yi Liao
- 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
- Correspondence:
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105
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Zhu T, Li L, Feng L, Mo H, Ren M. Target of Rapamycin Regulates Genome Methylation Reprogramming to Control Plant Growth in Arabidopsis. Front Genet 2020; 11:186. [PMID: 32194640 PMCID: PMC7062917 DOI: 10.3389/fgene.2020.00186] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/17/2020] [Indexed: 12/11/2022] Open
Abstract
DNA methylation is an indispensable epigenetic modification that dynamically regulates gene expression and genome stability during cell growth and development processes. The target of rapamycin (TOR) has emerged as a central regulator to regulate many fundamental cellular metabolic processes from protein synthesis to autophagy in all eukaryotic species. However, little is known about the functions of TOR in DNA methylation. In this study, the synergistic growth inhibition of Arabidopsis seedlings can be observed when DNA methylation inhibitor azacitidine was combined with TOR inhibitors. Global DNA methylation level was evaluated using whole-genome bisulfite sequencing (WGBS) under TOR inhibition. Hypomethylation level of whole genome DNA was observed in AZD-8055 (AZD), rapamycin (RAP) and AZD + RAP treated Arabidopsis seedlings. Based on functional annotation and KEGG pathway analysis of differentially methylated genes (DMGs), most of DMGs were enriched in carbon metabolism, biosynthesis of amino acids and other metabolic processes. Importantly, the suppression of TOR caused the change in DNA methylation of the genes associated with plant hormone signal transduction, indicating that TOR played an important role in modulating phytohormone signals in Arabidopsis. These observations are expected to shed light on the novel functions of TOR in DNA methylation and provide some new insights into how TOR regulates genome DNA methylation to control plant growth.
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Affiliation(s)
- Tingting Zhu
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China.,School of Life Sciences, Chongqing University, Chongqing, China
| | - Linxuan Li
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China
| | - Li Feng
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China.,Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China
| | - Huijuan Mo
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China
| | - Maozhi Ren
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China.,Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China
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106
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Wolf S. Deviating from the Beaten Track: New Twists in Brassinosteroid Receptor Function. Int J Mol Sci 2020; 21:ijms21051561. [PMID: 32106564 PMCID: PMC7084826 DOI: 10.3390/ijms21051561] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/21/2020] [Accepted: 02/22/2020] [Indexed: 12/15/2022] Open
Abstract
A key feature of plants is their plastic development tailored to the environmental conditions. To integrate environmental signals with genetic growth regulatory programs, plants rely on a number of hormonal pathways, which are intimately connected at multiple levels. Brassinosteroids (BRs), a class of plant sterol hormones, are perceived by cell surface receptors and trigger responses instrumental in tailoring developmental programs to environmental cues. Arguably, BR signalling is one of the best-characterized plant signalling pathways, and the molecular composition of the core signal transduction cascade seems clear. However, BR research continues to reveal new twists to re-shape our view on this key signalling circuit. Here, exciting novel findings pointing to the plasma membrane as a key site for BR signalling modulation and integration with other pathways are reviewed and new inputs into the BR signalling pathway and emerging “non-canonical” functions of the BR receptor complex are highlighted. Together, this new evidence underscores the complexity of plant signalling integration and serves as a reminder that highly-interconnected signalling pathways frequently comprise non-linear aspects which are difficult to convey in classical conceptual models.
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Affiliation(s)
- Sebastian Wolf
- Centre for Organismal Studies (COS) Heidelberg, INF230, 69120 Heidelberg, Germany
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107
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Armarego-Marriott T, Sandoval-Ibañez O, Kowalewska Ł. Beyond the darkness: recent lessons from etiolation and de-etiolation studies. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:1215-1225. [PMID: 31854450 PMCID: PMC7031072 DOI: 10.1093/jxb/erz496] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 11/29/2019] [Indexed: 05/06/2023]
Abstract
The state of etiolation is generally defined by the presence of non-green plastids (etioplasts) in plant tissues that would normally contain chloroplasts. In the commonly used dark-grown seedling system, etiolation is coupled with a type of growth called skotomorphogenesis. Upon illumination, de-etiolation occurs, marked by the transition from etioplast to chloroplast, and, at the seedling level, a switch to photomorphogenic growth. Etiolation and de-etiolation systems are therefore important for understanding both the acquisition of photosynthetic capacity during chloroplast biogenesis and plant responses to light-the most relevant signal in the life and growth of the organism. In this review, we discuss recent discoveries (within the past 2-3 years) in the field of etiolation and de-etiolation, with a particular focus on post-transcriptional processes and ultrastructural changes. We further discuss ambiguities in definitions of the term 'etiolation', and benefits and biases of common etiolation/de-etiolation systems. Finally, we raise several open questions and future research possibilities.
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Affiliation(s)
| | | | - Łucja Kowalewska
- Faculty of Biology, Department of Plant Anatomy and Cytology, University of Warsaw, Warszawa, Poland
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108
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Nolan TM, Vukašinović N, Liu D, Russinova E, Yin Y. Brassinosteroids: Multidimensional Regulators of Plant Growth, Development, and Stress Responses. THE PLANT CELL 2020; 32:295-318. [PMID: 31776234 PMCID: PMC7008487 DOI: 10.1105/tpc.19.00335] [Citation(s) in RCA: 398] [Impact Index Per Article: 99.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 10/01/2019] [Accepted: 11/26/2019] [Indexed: 05/18/2023]
Abstract
Brassinosteroids (BRs) are a group of polyhydroxylated plant steroid hormones that are crucial for many aspects of a plant's life. BRs were originally characterized for their function in cell elongation, but it is becoming clear that they play major roles in plant growth, development, and responses to several stresses such as extreme temperatures and drought. A BR signaling pathway from cell surface receptors to central transcription factors has been well characterized. Here, we summarize recent progress toward understanding the BR pathway, including BR perception and the molecular mechanisms of BR signaling. Next, we discuss the roles of BRs in development and stress responses. Finally, we show how knowledge of the BR pathway is being applied to manipulate the growth and stress responses of crops. These studies highlight the complex regulation of BR signaling, multiple points of crosstalk between BRs and other hormones or stress responses, and the finely tuned spatiotemporal regulation of BR signaling.
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Affiliation(s)
- Trevor M Nolan
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011
| | - Nemanja Vukašinović
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
- Center for Plant Systems Biology, Vlaams Instituut voor Biotechnologie, 9052, Ghent, Belgium
| | - Derui Liu
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
- Center for Plant Systems Biology, Vlaams Instituut voor Biotechnologie, 9052, Ghent, Belgium
| | - Eugenia Russinova
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
- Center for Plant Systems Biology, Vlaams Instituut voor Biotechnologie, 9052, Ghent, Belgium
| | - Yanhai Yin
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011
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109
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Chi C, Li X, Fang P, Xia X, Shi K, Zhou Y, Zhou J, Yu J. Brassinosteroids act as a positive regulator of NBR1-dependent selective autophagy in response to chilling stress in tomato. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:1092-1106. [PMID: 31639824 DOI: 10.1093/jxb/erz466] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 10/08/2019] [Indexed: 05/20/2023]
Abstract
Autophagy is a highly conserved and regulated catabolic process involved in the degradation of protein aggregates, which plays critical roles in eukaryotes. In plants, multiple molecular processes can induce or suppress autophagy but the mechanism of its regulation by phytohormones is poorly understood. Brassinosteroids (BRs) are steroid phytohormones that play crucial roles in plant response to stresses. Here, we investigate the role of BRs in NBR1-dependent selective autophagy in response to chilling stress in tomato. BRs and their signaling element BZR1 can induce autophagy and accumulation of the selective autophagy receptor NBR1 in tomato under chilling stress. Cold increased the stability of BZR1, which was promoted by BRs. Cold- and BR-induced increased BZR1 stability activated the transcription of several autophagy-related genes (ATGs) and NBR1 genes by directly binding to their promoters, which resulted in selective autophagy. Furthermore, silencing of these ATGs or NBR1 genes resulted in a decreased accumulation of several functional proteins and an increased accumulation of ubiquitinated proteins, subsequently compromising BR-induced cold tolerance. These results strongly suggest that BRs regulate NBR1-dependent selective autophagy in a BZR1-dependent manner in response to chilling stress in tomato.
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Affiliation(s)
- Cheng Chi
- Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou, China
| | - Xiaomeng Li
- Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou, China
| | - Pingping Fang
- Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou, China
| | - Xiaojian Xia
- Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou, China
| | - Kai Shi
- Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou, China
| | - Yanhong Zhou
- Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou, China
| | - Jie Zhou
- Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou, China
| | - Jingquan Yu
- Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou, China
- Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Hangzhou, China
- Key Laboratory of Horticultural Plants Growth, Development and Quality Improvement, Agricultural Ministry of China, Hangzhou, China
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110
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Coordination and Crosstalk between Autophagosome and Multivesicular Body Pathways in Plant Stress Responses. Cells 2020; 9:cells9010119. [PMID: 31947769 PMCID: PMC7017292 DOI: 10.3390/cells9010119] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 12/18/2019] [Accepted: 12/20/2019] [Indexed: 12/14/2022] Open
Abstract
In eukaryotic cells, autophagosomes and multivesicular bodies (MVBs) are two closely related partners in the lysosomal/vacuolar protein degradation system. Autophagosomes are double membrane-bound organelles that transport cytoplasmic components, including proteins and organelles for autophagic degradation in the lysosomes/vacuoles. MVBs are single-membrane organelles in the endocytic pathway that contain intraluminal vesicles whose content is either degraded in the lysosomes/vacuoles or recycled to the cell surface. In plants, both autophagosome and MVB pathways play important roles in plant responses to biotic and abiotic stresses. More recent studies have revealed that autophagosomes and MVBs also act together in plant stress responses in a variety of processes, including deployment of defense-related molecules, regulation of cell death, trafficking and degradation of membrane and soluble constituents, and modulation of plant hormone metabolism and signaling. In this review, we discuss these recent findings on the coordination and crosstalk between autophagosome and MVB pathways that contribute to the complex network of plant stress responses.
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111
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Cao JJ, Liu CX, Shao SJ, Zhou J. Molecular Mechanisms of Autophagy Regulation in Plants and Their Applications in Agriculture. FRONTIERS IN PLANT SCIENCE 2020; 11:618944. [PMID: 33664753 PMCID: PMC7921839 DOI: 10.3389/fpls.2020.618944] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 12/28/2020] [Indexed: 05/03/2023]
Abstract
Autophagy is a highly conserved cellular process for the degradation and recycling of unnecessary cytoplasmic components in eukaryotes. Various studies have shown that autophagy plays a crucial role in plant growth, productivity, and survival. The extensive functions of plant autophagy have been revealed in numerous frontier studies, particularly those regarding growth adjustment, stress tolerance, the identification of related genes, and the involvement of metabolic pathways. However, elucidation of the molecular regulation of plant autophagy, particularly the upstream signaling elements, is still lagging. In this review, we summarize recent progress in research on the molecular mechanisms of autophagy regulation, including the roles of protein kinases, phytohormones, second messengers, and transcriptional and epigenetic control, as well as the relationship between autophagy and the 26S proteasome in model plants and crop species. We also discuss future research directions for the potential application of autophagy in agriculture.
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Affiliation(s)
- Jia-Jian Cao
- Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Department of Horticulture, Zhejiang University, Hangzhou, China
| | - Chen-Xu Liu
- Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Department of Horticulture, Zhejiang University, Hangzhou, China
| | - Shu-Jun Shao
- Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Department of Horticulture, Zhejiang University, Hangzhou, China
- Key Laboratory of Horticultural Plants Growth, Development and Quality Improvement, Agricultural Ministry of China, Hangzhou, China
| | - Jie Zhou
- Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Department of Horticulture, Zhejiang University, Hangzhou, China
- Key Laboratory of Horticultural Plants Growth, Development and Quality Improvement, Agricultural Ministry of China, Hangzhou, China
- *Correspondence: Jie Zhou,
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112
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Su T, Li X, Yang M, Shao Q, Zhao Y, Ma C, Wang P. Autophagy: An Intracellular Degradation Pathway Regulating Plant Survival and Stress Response. FRONTIERS IN PLANT SCIENCE 2020; 11:164. [PMID: 32184795 PMCID: PMC7058704 DOI: 10.3389/fpls.2020.00164] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/03/2020] [Indexed: 05/18/2023]
Abstract
Autophagy is an intracellular process that facilitates the bulk degradation of cytoplasmic materials by the vacuole or lysosome in eukaryotes. This conserved process is achieved through the coordination of different autophagy-related genes (ATGs). Autophagy is essential for recycling cytoplasmic material and eliminating damaged or dysfunctional cell constituents, such as proteins, aggregates or even entire organelles. Plant autophagy is necessary for maintaining cellular homeostasis under normal conditions and is upregulated during abiotic and biotic stress to prolong cell life. In this review, we present recent advances on our understanding of the molecular mechanisms of autophagy in plants and how autophagy contributes to plant development and plants' adaptation to the environment.
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Affiliation(s)
| | | | | | | | | | - Changle Ma
- *Correspondence: Changle Ma, ; Pingping Wang,
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113
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Zhu T, Li L, Feng L, Mo H, Ren M. Target of Rapamycin Regulates Genome Methylation Reprogramming to Control Plant Growth in Arabidopsis. Front Genet 2020. [PMID: 32194640 DOI: 10.3389/fgene.2020.0018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2023] Open
Abstract
DNA methylation is an indispensable epigenetic modification that dynamically regulates gene expression and genome stability during cell growth and development processes. The target of rapamycin (TOR) has emerged as a central regulator to regulate many fundamental cellular metabolic processes from protein synthesis to autophagy in all eukaryotic species. However, little is known about the functions of TOR in DNA methylation. In this study, the synergistic growth inhibition of Arabidopsis seedlings can be observed when DNA methylation inhibitor azacitidine was combined with TOR inhibitors. Global DNA methylation level was evaluated using whole-genome bisulfite sequencing (WGBS) under TOR inhibition. Hypomethylation level of whole genome DNA was observed in AZD-8055 (AZD), rapamycin (RAP) and AZD + RAP treated Arabidopsis seedlings. Based on functional annotation and KEGG pathway analysis of differentially methylated genes (DMGs), most of DMGs were enriched in carbon metabolism, biosynthesis of amino acids and other metabolic processes. Importantly, the suppression of TOR caused the change in DNA methylation of the genes associated with plant hormone signal transduction, indicating that TOR played an important role in modulating phytohormone signals in Arabidopsis. These observations are expected to shed light on the novel functions of TOR in DNA methylation and provide some new insights into how TOR regulates genome DNA methylation to control plant growth.
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Affiliation(s)
- Tingting Zhu
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Linxuan Li
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China
| | - Li Feng
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China
| | - Huijuan Mo
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China
| | - Maozhi Ren
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China
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114
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Cao P, Kim SJ, Xing A, Schenck CA, Liu L, Jiang N, Wang J, Last RL, Brandizzi F. Homeostasis of branched-chain amino acids is critical for the activity of TOR signaling in Arabidopsis. eLife 2019; 8:e50747. [PMID: 31808741 PMCID: PMC6937141 DOI: 10.7554/elife.50747] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 12/05/2019] [Indexed: 01/11/2023] Open
Abstract
The target of rapamycin (TOR) kinase is an evolutionarily conserved hub of nutrient sensing and metabolic signaling. In plants, a functional connection of TOR activation with glucose availability was demonstrated, while it is yet unclear whether branched-chain amino acids (BCAAs) are a primary input of TOR signaling as they are in yeast and mammalian cells. Here, we report on the characterization of an Arabidopsis mutant over-accumulating BCAAs. Through chemical interventions targeting TOR and by examining mutants of BCAA biosynthesis and TOR signaling, we found that BCAA over-accumulation leads to up-regulation of TOR activity, which causes reorganization of the actin cytoskeleton and actin-associated endomembranes. Finally, we show that activation of TOR is concomitant with alteration of cell expansion, proliferation and specialized metabolism, leading to pleiotropic effects on plant growth and development. These results demonstrate that BCAAs contribute to plant TOR activation and reveal previously uncharted downstream subcellular processes of TOR signaling.
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Affiliation(s)
- Pengfei Cao
- MSU-DOE Plant Research LabMichigan State UniversityEast LansingUnited States
- Department of Plant BiologyMichigan State UniversityEast LansingUnited States
| | - Sang-Jin Kim
- Great Lakes Bioenergy Research Center, Michigan State UniversityEast LansingUnited States
| | - Anqi Xing
- Department of Biochemistry and Molecular BiologyMichigan State UniversityEast LansingUnited States
| | - Craig A Schenck
- Department of Biochemistry and Molecular BiologyMichigan State UniversityEast LansingUnited States
| | - Lu Liu
- MSU-DOE Plant Research LabMichigan State UniversityEast LansingUnited States
| | - Nan Jiang
- Department of Biochemistry and Molecular BiologyMichigan State UniversityEast LansingUnited States
| | - Jie Wang
- Department of Plant BiologyMichigan State UniversityEast LansingUnited States
| | - Robert L Last
- Department of Plant BiologyMichigan State UniversityEast LansingUnited States
- Department of Biochemistry and Molecular BiologyMichigan State UniversityEast LansingUnited States
| | - Federica Brandizzi
- MSU-DOE Plant Research LabMichigan State UniversityEast LansingUnited States
- Department of Plant BiologyMichigan State UniversityEast LansingUnited States
- Great Lakes Bioenergy Research Center, Michigan State UniversityEast LansingUnited States
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115
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Li B, Wang Y, Zhang Y, Tian W, Chong K, Jang JC, Wang L. PRR5, 7 and 9 positively modulate TOR signaling-mediated root cell proliferation by repressing TANDEM ZINC FINGER 1 in Arabidopsis. Nucleic Acids Res 2019; 47:5001-5015. [PMID: 30892623 PMCID: PMC6547441 DOI: 10.1093/nar/gkz191] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 03/04/2019] [Accepted: 03/12/2019] [Indexed: 12/22/2022] Open
Abstract
Circadian clock coordinates numerous plant growth and developmental processes including cell elongation in the hypocotyl, whether or not it modulates cell proliferation is largely unknown. Here we have found that Pseudo Response Regulators (PRRs), essential components of circadian core oscillators, affect root meristem cell proliferation mediated by Target Of Rapamycin (TOR) signaling. The null mutants of PRRs display much reduced sensitivities to sugar-activated TOR signaling. We have subsequently identified Tandem Zinc Finger 1, encoding a processing body localized RNA-binding protein, as a direct target repressed by PRRs in mediating TOR signaling. Multiple lines of biochemical and genetic evidence have demonstrated that TZF1 acts downstream of PRRs to attenuate TOR signaling. Furthermore, TZF1 could directly bind TOR mRNA via its tandem zinc finger motif to affect TOR mRNA stability. Our findings support a notion that PRR-TZF1-TOR molecular axis modulates root meristem cell proliferation by integrating both transcriptional and post-transcriptional regulatory mechanisms.
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Affiliation(s)
- Bin Li
- Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 10093, People's Republic of China
| | - Yan Wang
- Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 10093, People's Republic of China.,University of Chinese Academy of Sciences
| | - Yuanyuan Zhang
- Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 10093, People's Republic of China
| | - Wenwen Tian
- Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 10093, People's Republic of China.,University of Chinese Academy of Sciences
| | - Kang Chong
- Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 10093, People's Republic of China
| | - Jyan-Chyun Jang
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH 43210, USA.,Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Lei Wang
- Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 10093, People's Republic of China.,University of Chinese Academy of Sciences
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116
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Yaguchi M, Ikeya S, Kozaki A. The activation mechanism of plant S6 kinase (S6K), a substrate of TOR kinase, is different from that of mammalian S6K. FEBS Lett 2019; 594:776-787. [PMID: 31705659 DOI: 10.1002/1873-3468.13661] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 11/06/2022]
Abstract
The S6 kinases (S6Ks) are known to be activated by the target of rapamycin through phosphorylation of their hydrophobic motif (HM). However, our previous research showed that the HM site of plant S6Ks is not phosphorylated and is not essential for their activity in yeast cells lacking Ypk3, an ortholog of mammalian S6K. Here, we demonstrate that the HM site of mammalian S6Ks is phosphorylated and is indispensable for their activity in yeast ypk3∆ cells. Furthermore, pseudo-phosphorylation at the HM site of plant S6Ks results in regaining of activity that is lost due to mutation in the conserved phosphorylation sites, namely the T-loop and Turn motif. These results indicate the activation mechanism of plant S6Ks is different from that of mammals.
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Affiliation(s)
| | - Shun Ikeya
- Department of Biology, Shizuoka University, Japan
| | - Akiko Kozaki
- Department of Biology, Shizuoka University, Japan
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117
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Upadhyaya S, Rao BJ. Reciprocal regulation of photosynthesis and mitochondrial respiration by TOR kinase in Chlamydomonas reinhardtii. PLANT DIRECT 2019; 3:e00184. [PMID: 31832599 PMCID: PMC6854518 DOI: 10.1002/pld3.184] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 10/21/2019] [Accepted: 10/29/2019] [Indexed: 05/03/2023]
Abstract
While the role of TOR kinase in the chloroplast biogenesis and transcriptional regulation of photosynthesis is well documented in Arabidopsis, the functional relevance of this metabolic sensor kinase in chloroplast-mitochondria cross talk is unknown. Using Chlamydomonas reinhardtii as the model system, we demonstrate the role of TOR kinase in the regulation of chloroplast and mitochondrial functions: We show that TOR kinase inhibition impairs the maintenance of high ETR associated with PSII and low NPQ and inhibits efficient state transitions between PSII and PSI. While compromised photosynthetic functions are observed in TOR kinase inhibited cells, same conditions lead to augmentation in mitochondrial basal respiration rate by twofold and concomitantly a rise in ATP production. Interestingly, such upregulated mitochondrial functions in TOR-inhibited cells are mediated by fragmented mitochondria via upregulating COXIIb and downregulating Hxk1 and AOX1 protein levels. We propose that TOR kinase may act as a sensor that counter-regulates chloroplast versus mitochondrial functions in a normal C. reinhardtii cell.
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Affiliation(s)
- Shivani Upadhyaya
- Department of Biological SciencesTata Institute of Fundamental Research (TIFR)MumbaiIndia
| | - Basuthkar Jagadeeshwar Rao
- Indian Institute of Science Education and Research (IISER) TirupatiTransit Campus: Sree Rama Engineering CollegeTirupatiIndia
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118
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Rodriguez M, Parola R, Andreola S, Pereyra C, Martínez-Noël G. TOR and SnRK1 signaling pathways in plant response to abiotic stresses: Do they always act according to the "yin-yang" model? PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 288:110220. [PMID: 31521220 DOI: 10.1016/j.plantsci.2019.110220] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 08/05/2019] [Accepted: 08/13/2019] [Indexed: 05/20/2023]
Abstract
Plants are sessile photo-autotrophic organisms continuously exposed to a variety of environmental stresses. Monitoring the sugar level and energy status is essential, since this knowledge allows the integration of external and internal cues required for plant physiological and developmental plasticity. Most abiotic stresses induce severe metabolic alterations and entail a great energy cost, restricting plant growth and producing important crop losses. Therefore, balancing energy requirements with supplies is a major challenge for plants under unfavorable conditions. The conserved kinases target of rapamycin (TOR) and sucrose-non-fermenting-related protein kinase-1 (SnRK1) play central roles during plant growth and development, and in response to environmental stresses; these kinases affect cellular processes and metabolic reprogramming, which has physiological and phenotypic consequences. The "yin-yang" model postulates that TOR and SnRK1 act in opposite ways in the regulation of metabolic-driven processes. In this review, we describe and discuss the current knowledge about the complex and intricate regulation of TOR and SnRK1 under abiotic stresses. We especially focus on the physiological perspective that, under certain circumstances during the plant stress response, the TOR and SnRK1 kinases could be modulated differently from what is postulated by the "yin-yang" concept.
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Affiliation(s)
- Marianela Rodriguez
- Instituto de Fisiología y Recursos Genéticos Vegetales (IFRGV), Centro de Investigaciones Agropecuarias (CIAP), Instituto Nacional de Tecnología Agropecuaria (INTA), Camino 60 Cuadras km 5.5, X5020ICA, Córdoba, Argentina; Unidad de Estudios Agropecuarios (UDEA- CONICET), Camino 60 Cuadras km 5.5 X5020ICA, Córdoba, Argentina.
| | - Rodrigo Parola
- Instituto de Fisiología y Recursos Genéticos Vegetales (IFRGV), Centro de Investigaciones Agropecuarias (CIAP), Instituto Nacional de Tecnología Agropecuaria (INTA), Camino 60 Cuadras km 5.5, X5020ICA, Córdoba, Argentina; Unidad de Estudios Agropecuarios (UDEA- CONICET), Camino 60 Cuadras km 5.5 X5020ICA, Córdoba, Argentina.
| | - Sofia Andreola
- Instituto de Fisiología y Recursos Genéticos Vegetales (IFRGV), Centro de Investigaciones Agropecuarias (CIAP), Instituto Nacional de Tecnología Agropecuaria (INTA), Camino 60 Cuadras km 5.5, X5020ICA, Córdoba, Argentina; Unidad de Estudios Agropecuarios (UDEA- CONICET), Camino 60 Cuadras km 5.5 X5020ICA, Córdoba, Argentina.
| | - Cintia Pereyra
- Instituto de Investigaciones en Biodiversidad y Biotecnología (INBIOTEC-CONICET), y Fundación para Investigaciones Biológicas Aplicadas (FIBA), Vieytes 3103, 7600, Mar del Plata, Argentina.
| | - Giselle Martínez-Noël
- Instituto de Investigaciones en Biodiversidad y Biotecnología (INBIOTEC-CONICET), y Fundación para Investigaciones Biológicas Aplicadas (FIBA), Vieytes 3103, 7600, Mar del Plata, Argentina.
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119
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Hwang G, Kim S, Cho J, Paik I, Kim J, Oh E. Trehalose-6-phosphate signaling regulates thermoresponsive hypocotyl growth in Arabidopsis thaliana. EMBO Rep 2019; 20:e47828. [PMID: 31393060 PMCID: PMC6776909 DOI: 10.15252/embr.201947828] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 06/26/2019] [Accepted: 07/12/2019] [Indexed: 12/30/2022] Open
Abstract
Growth plasticity is a key mechanism by which plants adapt to the ever-changing environmental conditions. Since growth is a high-energy-demanding and irreversible process, it is expected to be regulated by the integration of endogenous energy status as well as environmental conditions. Here, we show that trehalose-6-phosphate (T6P) functions as a sugar signaling molecule that coordinates thermoresponsive hypocotyl growth with endogenous sugar availability. We found that the loss of T6P SYNTHASE 1 (TPS1) in Arabidopsis thaliana impaired high-temperature-mediated hypocotyl growth. Consistently, the activity of PIF4, a transcription factor that positively regulates hypocotyl growth, was compromised in the tps1 mutant. We further show that, in the tps1 mutant, a sugar signaling kinase KIN10 directly phosphorylates and destabilizes PIF4. T6P inhibits KIN10 activity in a GRIK-dependent manner, allowing PIF4 to promote hypocotyl growth at high temperatures. Together, our results demonstrate that T6P determines thermoresponsive growth through the KIN10-PIF4 signaling module. Such regulation of PIF4 by T6P integrates the temperature-signaling pathway with the endogenous sugar status, thus optimizing plant growth response to environmental stresses.
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Affiliation(s)
- Geonhee Hwang
- Department of Life SciencesKorea UniversitySeoulKorea
| | - Sara Kim
- Department of Life SciencesKorea UniversitySeoulKorea
| | - Jae‐Yong Cho
- Department of Biotechnology and Kumho Life Science LaboratoryChonnam National UniversityGwangjuKorea
| | - Inyup Paik
- Department of Molecular BiosciencesThe Institute for Cellular and Molecular BiologyUniversity of TexasAustinTXUSA
| | - Jeong‐Il Kim
- Department of Biotechnology and Kumho Life Science LaboratoryChonnam National UniversityGwangjuKorea
| | - Eunkyoo Oh
- Department of Life SciencesKorea UniversitySeoulKorea
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120
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Amorim-Silva V, García-Moreno Á, Castillo AG, Lakhssassi N, Esteban Del Valle A, Pérez-Sancho J, Li Y, Posé D, Pérez-Rodriguez J, Lin J, Valpuesta V, Borsani O, Zipfel C, Macho AP, Botella MA. TTL Proteins Scaffold Brassinosteroid Signaling Components at the Plasma Membrane to Optimize Signal Transduction in Arabidopsis. THE PLANT CELL 2019; 31:1807-1828. [PMID: 31189737 PMCID: PMC6713313 DOI: 10.1105/tpc.19.00150] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/07/2019] [Accepted: 05/31/2019] [Indexed: 05/20/2023]
Abstract
Brassinosteroids (BRs) form a group of steroidal hormones essential for plant growth, development, and stress responses. BRs are perceived extracellularly by plasma membrane receptor-like kinases that activate an interconnected signal transduction cascade, leading to the transcriptional regulation of BR-responsive genes. TETRATRICOPEPTIDE THIOREDOXIN-LIKE (TTL) genes are specific for land plants, and their encoded proteins are defined by the presence of protein-protein interaction motives, that is, an intrinsic disordered region at the N terminus, six tetratricopeptide repeat domains, and a C terminus with homology to thioredoxins. TTL proteins thus likely mediate the assembly of multiprotein complexes. Phenotypic, molecular, and genetic analyses show that TTL proteins are positive regulators of BR signaling in Arabidopsis (Arabidopsis thaliana). TTL3 directly interacts with a constitutively active BRASSINOSTEROID INSENSITIVE1 (BRI1) receptor kinase, BRI1-SUPPRESSOR1 phosphatase, and the BRASSINAZOLE RESISTANT1 transcription factor and associates with BR-SIGNALING KINASE1, BRASSINOSTEROID INSENSITIVE2 kinases, but not with BRI1-ASSOCIATED KINASE1. A functional TTL3-green fluorescent protein (GFP) shows dual cytoplasmic plasma membrane localization. Depleting the endogenous BR content reduces plasma membrane localization of TTL3-GFP, while increasing BR content causes its plasma membrane relocalization, where it strengthens the association of BR signaling components. Our results reveal that TTL proteins promote BR responses and suggest that TTL proteins may function as scaffold proteins by bringing together cytoplasmic and plasma membrane BR signaling components.
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Affiliation(s)
- Vítor Amorim-Silva
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora," Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Campus Teatinos, 29071 Málaga, Spain
| | - Álvaro García-Moreno
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora," Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Campus Teatinos, 29071 Málaga, Spain
| | - Araceli G Castillo
- Departamento de Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora," Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Campus Teatinos, 29071 Málaga, Spain
| | - Naoufal Lakhssassi
- Department of Plant, Soil and Agricultural Systems, Southern Illinois University, Carbondale, Illinois 62901
| | - Alicia Esteban Del Valle
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora," Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Campus Teatinos, 29071 Málaga, Spain
| | - Jessica Pérez-Sancho
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora," Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Campus Teatinos, 29071 Málaga, Spain
| | - Yansha Li
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences (CAS), Shanghai, China
| | - David Posé
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora," Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Campus Teatinos, 29071 Málaga, Spain
| | - Josefa Pérez-Rodriguez
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora," Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Campus Teatinos, 29071 Málaga, Spain
| | - Jinxing Lin
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
| | - Victoriano Valpuesta
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora," Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Campus Teatinos, 29071 Málaga, Spain
| | - Omar Borsani
- Departamento de Biología Vegetal, Laboratorio de Bioquímica, Facultad de Agronomía Universidad de la República, Montevideo, Uruguay
| | - Cyril Zipfel
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, NR4 7UH, United Kingdom
- Institute of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zurich, Switzerland
| | - Alberto P Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences (CAS), Shanghai, China
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, NR4 7UH, United Kingdom
| | - Miguel A Botella
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora," Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Campus Teatinos, 29071 Málaga, Spain
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121
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Bouré N, Kumar SV, Arnaud N. The BAP Module: A Multisignal Integrator Orchestrating Growth. TRENDS IN PLANT SCIENCE 2019; 24:602-610. [PMID: 31076166 DOI: 10.1016/j.tplants.2019.04.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 04/01/2019] [Accepted: 04/11/2019] [Indexed: 05/22/2023]
Abstract
Coordination of cell proliferation, cell expansion, and differentiation underpins plant growth. To maximise reproductive success, growth needs to be fine-tuned in response to endogenous and environmental cues. This developmental plasticity relies on a cellular machinery that integrates diverse signals and coordinates the downstream responses. In arabidopsis, the BAP regulatory module, which includes the BRASSINAZOLE RESISTANT 1 (BZR1), AUXIN RESPONSE FACTOR 6 (ARF6), and PHYTOCHROME INTERACTING FACTOR 4 (PIF4) transcription factors (TFs), has been shown to coordinate growth in response to multiple growth-regulating signals. In this Opinion article, we provide an integrative view on the BAP module control of cell expansion and discuss whether its function is conserved or diversified, thus providing new insights into the molecular control of growth.
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Affiliation(s)
- Nathalie Bouré
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France; Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - S Vinod Kumar
- Department of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Nicolas Arnaud
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France.
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122
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Autophagy in Plant: A New Orchestrator in the Regulation of the Phytohormones Homeostasis. Int J Mol Sci 2019; 20:ijms20122900. [PMID: 31197094 PMCID: PMC6627538 DOI: 10.3390/ijms20122900] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/07/2019] [Accepted: 06/13/2019] [Indexed: 12/15/2022] Open
Abstract
Autophagy is a highly evolutionarily-conserved catabolic process facilitating the development and survival of organisms which have undergone favorable and/or stressful conditions, in particular the plant. Accumulating evidence has implicated that autophagy is involved in growth and development, as well as responses to various stresses in plant. Similarly, phytohormones also play a pivotal role in the response to various stresses in addition to the plant growth and development. However, the relationship between autophagy and phytohormones still remains poorly understood. Here, we review advances in the crosstalk between them upon various environmental stimuli. We also discuss how autophagy coordinates the phytohormones to regulate plant growth and development. We propose that unraveling the regulatory role(s) of autophagy in modulating the homeostasis of phytohormones would benefit crop breeding and improvement under variable environments, in particular under suboptimal conditions.
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123
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Sharma M, Banday ZZ, Shukla BN, Laxmi A. Glucose-Regulated HLP1 Acts as a Key Molecule in Governing Thermomemory. PLANT PHYSIOLOGY 2019; 180:1081-1100. [PMID: 30890662 PMCID: PMC6548265 DOI: 10.1104/pp.18.01371] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 03/04/2019] [Indexed: 05/04/2023]
Abstract
Induction of heat shock proteins (HSPs) in response to heat stress (HS) is indispensable for conferring thermotolerance. Glc, a fundamental signaling and metabolic molecule, provides energy to stressed seedlings to combat stress. The recovery of stressed plants from detrimental HS in response to Glc is largely mediated by HSPs, but the mechanistic basis of this thermotolerance is not well defined. In this study, we show that Glc has a prominent role in providing thermotolerance. Glc-mediated thermotolerance involves HSP induction via the TARGET OF RAPAMYCIN (TOR)-E2Fa signaling module. Apart from HSPs, TOR-E2Fa also regulates the Arabidopsis (Arabidopsis thaliana) ortholog of human Hikeshi, named HIKESHI-LIKE PROTEIN1 (HLP1). Expression of proHLP1::GUS in the shoot apical meristem (SAM) after HS coincides with TOR-E2Fa expression, substantiating a role for TOR-E2Fa-HLP1 in providing thermotolerance. We also demonstrate that Glc along with heat could induce proliferation activity in the SAM after HS recovery, which was arrested by the TOR inhibitor AZD-8055. Molecular and physiological studies suggest that HS-activated heat stress transcription factor A1s also positively regulate HLP1 transcription, suggesting convergence of the Glc and HS signaling pathways. Loss of functional HLP1 causes HS hypersensitivity, whereas HLP1 overexpressors display increased thermotolerance. HLP1 binds to the promoters of Glc-regulated HS-responsive genes and promotes chromatin acetylation. In addition, Glc modifies the chromatin landscape at thermomemory-related loci by promoting H3K4 trimethylation (H3K4me3). Glc-primed accumulation of H3K4me3 at thermomemory-associated loci is mediated through HLP1. These findings reveal the novel function of Glc-regulated HLP1 in mediating thermotolerance/thermomemory response.
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Affiliation(s)
- Mohan Sharma
- National Institute of Plant Genome Research, New Delhi-110067, India
| | | | | | - Ashverya Laxmi
- National Institute of Plant Genome Research, New Delhi-110067, India
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A Dwarf Phenotype Identified in Breadfruit (Artocarpus altilis) Plants Growing on Marang (A. odoratissimus) Rootstocks. HORTICULTURAE 2019. [DOI: 10.3390/horticulturae5020040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Breadfruit (Artocarpus altilis) is a tropical fruit tree primarily grown as a staple crop for food security in Oceania. Significant wind damage has driven an interest in developing its dwarf phenotype. The presence of any dwarf breadfruit variety remains unknown. Little is known regarding the growth of the species on rootstocks. Here, we examined the phenotype of breadfruit plants growing on marang (Artocarpus odoratissimus) rootstocks within 18 months after grafting; we identified a rootstock-induced dwarf trait in the species. This dwarf phenotype was characterized by shorter stems, reduced stem thickness and fewer branches, with 73% shorter internode length, 51% fewer and 40% smaller leaves compared to standard size breadfruit plants. The height of breadfruit plants on marang rootstocks was reduced by 49% in 9 months, and 59% in 18 months after grafting. The results suggest marang rootstocks can be applied to breadfruit breeding program for tree vigor control. Further biochemical characterization showed plants on marang rootstocks displayed leaves without change of total chlorophyll content, but with lower total soluble sugars, and stems with reduced activity of plasma membrane H+-ATPase, a well-known primary proton pump essential for nutrient transport. The significance of the two parameters in rootstock dwarfing is discussed.
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125
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Son O, Kim S, Kim D, Hur YS, Kim J, Cheon CI. Involvement of TOR signaling motif in the regulation of plant autophagy. Biochem Biophys Res Commun 2019; 501:643-647. [PMID: 29738770 DOI: 10.1016/j.bbrc.2018.05.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 05/04/2018] [Indexed: 01/22/2023]
Abstract
In our previous studies, we have demonstrated that a stretch of amino-acid sequences identified from Arabidopsis ribosomal S6 kinase 1 (AtS6K1) provided a plant version of the TOS (TOR-signaling) motif, mediating the interaction with the Raptor protein in the TOR (Target of Rapamycin) kinase complex. Here we report the presence of same element in Arabidopsis Autophagy related-13 (AtATG13) protein, which is a key component of the plant autophagy response. Its composition is nearly identical to that found in the AtS6K1 in the five-amino-acid core sequence, and the presence of this five-amino-acid sequence was found to be essential for its interaction with the Raptor protein. A mutant AtATG13 protein lacking this five-amino-acid element conferred an elevated autophagy response and could not effectively phosphorylated by TOR kinase activity, demonstrating its role in mediating the TOR signaling to the components that carry it as a possible TOS motif. A ligand-binding simulation model using the MM-PBSA method indicates that both of the five-amino-acid sequence elements of AtS6K1 and AtATG13 have strong probability of making stable interface with the Raptor binding pocket, corroborating our proposition for this element as the plant TOS motif.
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Affiliation(s)
- Ora Son
- Department of Biological Science, Sookmyung Women's University, Seoul, 04310, South Korea
| | - Sunghan Kim
- Department of Biological Science, Sookmyung Women's University, Seoul, 04310, South Korea
| | - Dooil Kim
- Department of Biological Science, Chungbuk National University, Cheongju, 28644, South Korea
| | - Yoon-Sun Hur
- Department of Biological Science, Sookmyung Women's University, Seoul, 04310, South Korea
| | - Jiyoung Kim
- Department of Biological Science, Sookmyung Women's University, Seoul, 04310, South Korea
| | - Choong-Ill Cheon
- Department of Biological Science, Sookmyung Women's University, Seoul, 04310, South Korea.
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126
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Yang M, Bu F, Huang W, Chen L. Multiple Regulatory Levels Shape Autophagy Activity in Plants. FRONTIERS IN PLANT SCIENCE 2019; 10:532. [PMID: 31068964 PMCID: PMC6491747 DOI: 10.3389/fpls.2019.00532] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/05/2019] [Indexed: 05/29/2023]
Abstract
Autophagy is a strictly regulated pathway involving the degradation of cytoplasmic organelles and proteins. Most autophagy-related genes have been identified in plants based on sequence similarity to homologues in yeast and mammals. In addition, the molecular mechanisms underlying plant autophagy have been extensively studied in the last decade. Plant autophagy plays an important role in various stress responses, pathogen defense, and developmental processes such as seed germination, pollen maturation, and leaf senescence. However, the regulatory mechanisms of autophagy in plants remain poorly understood. Recent studies have identified several plant autophagy regulators, which modify autophagy activity at transcriptional, post-transcriptional, and post-translational levels. In this review, we summarize recent advances in understanding regarding regulatory network of plant autophagy and future directions in autophagy research.
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Ryabova LA, Robaglia C, Meyer C. Target of Rapamycin kinase: central regulatory hub for plant growth and metabolism. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2211-2216. [PMID: 30984977 PMCID: PMC6463030 DOI: 10.1093/jxb/erz108] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Affiliation(s)
- Lyubov A Ryabova
- Institut de Biologie Moléculaire des Plantes, UPR 2357 CNRS, Université de Strasbourg, Strasbourg, France
| | - Christophe Robaglia
- Laboratoire de Génétique et Biophysique des Plantes, UMR 7265, Aix Marseille Université, CEA, CNRS, BIAM, Faculté des Sciences de Luminy, Marseille, France
| | - Christian Meyer
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
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128
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Jamsheer K M, Jindal S, Laxmi A. Evolution of TOR-SnRK dynamics in green plants and its integration with phytohormone signaling networks. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2239-2259. [PMID: 30870564 DOI: 10.1093/jxb/erz107] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 02/26/2019] [Indexed: 05/07/2023]
Abstract
The target of rapamycin (TOR)-sucrose non-fermenting 1 (SNF1)-related protein kinase 1 (SnRK1) signaling is an ancient regulatory mechanism that originated in eukaryotes to regulate nutrient-dependent growth. Although the TOR-SnRK1 signaling cascade shows highly conserved functions among eukaryotes, studies in the past two decades have identified many important plant-specific innovations in this pathway. Plants also possess SnRK2 and SnRK3 kinases, which originated from the ancient SnRK1-related kinases and have specialized roles in controlling growth, stress responses and nutrient homeostasis in plants. Recently, an integrative picture has started to emerge in which different SnRKs and TOR kinase are highly interconnected to control nutrient and stress responses of plants. Further, these kinases are intimately involved with phytohormone signaling networks that originated at different stages of plant evolution. In this review, we highlight the evolution and divergence of TOR-SnRK signaling components in plants and their communication with each other as well as phytohormone signaling to fine-tune growth and stress responses in plants.
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Affiliation(s)
- Muhammed Jamsheer K
- Amity Food & Agriculture Foundation, Amity University Uttar Pradesh, Noida, India
| | - Sunita Jindal
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Ashverya Laxmi
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
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129
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Margalha L, Confraria A, Baena-González E. SnRK1 and TOR: modulating growth-defense trade-offs in plant stress responses. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2261-2274. [PMID: 30793201 DOI: 10.1093/jxb/erz066] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 02/07/2019] [Indexed: 05/11/2023]
Abstract
The evolutionarily conserved protein kinase complexes SnRK1 and TOR are central metabolic regulators essential for plant growth, development, and stress responses. They are activated by opposite signals, and the outcome of their activation is, in global terms, antagonistic. Similarly to their yeast and animal counterparts, SnRK1 is activated by the energy deficit often associated with stress to restore homeostasis, while TOR is activated in nutrient-rich conditions to promote growth. Recent evidence suggests that SnRK1 represses TOR in plants, revealing evolutionary conservation also in their crosstalk. Given their importance for integrating environmental information into growth and developmental programs, these signaling pathways hold great promise for reducing the growth penalties caused by stress. Here we review the literature connecting SnRK1 and TOR to plant stress responses. Although SnRK1 and TOR emerge mostly as positive regulators of defense and growth, respectively, the outcome of their activities in plant growth and performance is not always straightforward. Manipulation of both pathways under similar experimental setups, as well as further biochemical and genetic analyses of their molecular and functional interaction, is essential to fully understand the mechanisms through which these two metabolic pathways contribute to stress responses, growth, and development.
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Affiliation(s)
- Leonor Margalha
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande,Oeiras, Portugal
| | - Ana Confraria
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande,Oeiras, Portugal
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130
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Caldana C, Martins MCM, Mubeen U, Urrea-Castellanos R. The magic 'hammer' of TOR: the multiple faces of a single pathway in the metabolic regulation of plant growth and development. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2217-2225. [PMID: 30722050 DOI: 10.1093/jxb/ery459] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 12/11/2018] [Indexed: 06/09/2023]
Abstract
The target of rapamycin (TOR) pathway has emerged as a central hub synchronizing plant growth according to the nutrient/energy status and environmental inputs. Molecular mechanisms through which TOR promotes plant growth involve the positive regulation of transcription of cell proliferation-associated genes, mRNA translation initiation and ribosome biogenesis, to cite a few examples. Phytohormones, light, sugars, and sulfur have been found to broadly regulate TOR activity. TOR operates as a metabolic homeostat to fine-tune anabolic processes and efficiently enable plant growth under different circumstances. However, little is known about the multiple effectors that act up- and downstream of TOR. Here, we mainly discuss recent findings related to the TOR pathway in the context of plant metabolism and highlight areas of interest that need to be addressed to keep unravelling the intricate networks governing the regulation of TOR and its function in controlling biosynthetic growth.
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Affiliation(s)
- Camila Caldana
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
| | | | - Umarah Mubeen
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
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131
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Wu Y, Shi L, Li L, Fu L, Liu Y, Xiong Y, Sheen J. Integration of nutrient, energy, light, and hormone signalling via TOR in plants. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2227-2238. [PMID: 30715492 PMCID: PMC6463029 DOI: 10.1093/jxb/erz028] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/08/2019] [Indexed: 05/04/2023]
Abstract
The multidomain target of rapamycin (TOR) is an atypical serine/threonine protein kinase resembling phosphatidylinositol lipid kinases, but retains high sequence identity and serves a remarkably conserved role as a master signalling integrator in yeasts, plants, and humans. TOR dynamically orchestrates cell metabolism, biogenesis, organ growth, and development transitions in response to nutrient, energy, hormone, and environmental cues. Here we review recent findings on the versatile and complex roles of TOR in transcriptome reprogramming, seedling, root, and shoot growth, and root hair production activated by sugar and energy signalling. We explore how co-ordination of TOR-mediated light and hormone signalling is involved in root and shoot apical meristem activation, proliferation of leaf primordia, cotyledon/leaf greening, and hypocotyl elongation. We also discuss the emerging TOR functions in response to sulfur assimilation and metabolism and consider potential molecular links and positive feedback loops between TOR, sugar, energy, and other essential macronutrients.
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Affiliation(s)
- Yue Wu
- Department of Molecular Biology and Centre for Computational and Integrative Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Lin Shi
- Department of Molecular Biology and Centre for Computational and Integrative Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Lei Li
- Department of Molecular Biology and Centre for Computational and Integrative Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Liwen Fu
- Basic Forestry and Proteomics Research Centre, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fujian Province, PR China
| | - Yanlin Liu
- Basic Forestry and Proteomics Research Centre, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fujian Province, PR China
| | - Yan Xiong
- Basic Forestry and Proteomics Research Centre, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fujian Province, PR China
| | - Jen Sheen
- Department of Molecular Biology and Centre for Computational and Integrative Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, MA, USA
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132
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Wang H, Schippers JHM. The Role and Regulation of Autophagy and the Proteasome During Aging and Senescence in Plants. Genes (Basel) 2019; 10:genes10040267. [PMID: 30987024 PMCID: PMC6523301 DOI: 10.3390/genes10040267] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/06/2019] [Accepted: 03/27/2019] [Indexed: 12/18/2022] Open
Abstract
Aging and senescence in plants has a major impact on agriculture, such as in crop yield, the value of ornamental crops, and the shelf life of vegetables and fruits. Senescence represents the final developmental phase of the leaf and inevitably results in the death of the organ. Still, the process is completely under the control of the plant. Plants use their protein degradation systems to maintain proteostasis and transport or salvage nutrients from senescing organs to develop reproductive parts. Herein, we present an overview of current knowledge about the main protein degradation pathways in plants during senescence: The proteasome and autophagy. Although both pathways degrade proteins, autophagy appears to prevent aging, while the proteasome functions as a positive regulator of senescence.
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Affiliation(s)
- Haojie Wang
- Institute of Biology I, RWTH Aachen University, 52074 Aachen, Germany.
| | - Jos H M Schippers
- Institute of Biology I, RWTH Aachen University, 52074 Aachen, Germany.
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133
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Kim EJ, Lee SH, Park CH, Kim SH, Hsu CC, Xu S, Wang ZY, Kim SK, Kim TW. Plant U-Box40 Mediates Degradation of the Brassinosteroid-Responsive Transcription Factor BZR1 in Arabidopsis Roots. THE PLANT CELL 2019; 31:791-808. [PMID: 30814258 PMCID: PMC6501603 DOI: 10.1105/tpc.18.00941] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/07/2019] [Accepted: 02/22/2019] [Indexed: 05/05/2023]
Abstract
Brassinosteroid (BR) regulates a wide range of physiological responses through the activation of BRASSINAZOLE RESISTANT1 (BZR1), whose activity is tightly controlled by its phosphorylation status and degradation. Although BZR1 appears to be degraded in distinct ways in response to different hormonal or environmental cues, little is known about how BR signaling regulates its degradation. Here we show that the BR-regulated U-box protein PUB40 mediates the proteasomal degradation of BZR1 in a root-specific manner in Arabidopsis (Arabidopsis thaliana). BZR1 levels were strongly reduced by plant U-box40 (PUB40) overexpression, whereas the pub39 pub40 pub41 mutant accumulated much more BZR1 than wild type in roots. The bzr1-1D gain-of-function mutation reduced the interaction with PUB40, which suppressed PUB40-mediated BZR1 degradation in roots. The cell layer-specific expression of PUB40 in roots helps induce selective BZR1 accumulation in the epidermal layer. Both BR treatment and loss-of-function of PUB40 expanded BZR1 accumulation to most cell layers. In addition, BZR1 accumulation increased the resistance of pub39 pub40 pub41 to low inorganic phosphate availability, as observed in bzr1-1D BRASSINOSTEROID-INSENSITIVE2-induced phosphorylation of PUB40, which mainly occurs in roots, gives rise to BZR1 degradation through enhanced binding of PUB40 to BZR1 and PUB40's stability. Our results suggest a molecular mechanism of root-specific BZR1 degradation regulated by BR signaling.
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Affiliation(s)
- Eun-Ji Kim
- Department of Life Science, Hanyang University, Seoul 04763, South Korea
| | - Se-Hwa Lee
- Department of Life Science, Hanyang University, Seoul 04763, South Korea
| | - Chan-Ho Park
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
| | - So-Hee Kim
- Department of Life Science, Hanyang University, Seoul 04763, South Korea
| | - Chuan-Chih Hsu
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
| | - Shouling Xu
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
| | - Zhi-Yong Wang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
| | - Seong-Ki Kim
- Department of Life Science, Chung-Ang University, Seoul 06974, South Korea
| | - Tae-Wuk Kim
- Department of Life Science, Hanyang University, Seoul 04763, South Korea
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763, South Korea
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134
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Bakshi A, Moin M, Madhav MS, Kirti PB. Target of rapamycin, a master regulator of multiple signalling pathways and a potential candidate gene for crop improvement. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:190-205. [PMID: 30411830 DOI: 10.1111/plb.12935] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 11/05/2018] [Indexed: 06/08/2023]
Abstract
The target of rapamycin (TOR) protein regulates growth and development in photosynthetic and non-photosynthetic eukaryotes. Although the TOR regulatory networks are involved in nutrient and energy signalling, and transcriptional and translational control of multiple signalling pathways, the molecular mechanism of TOR regulation of plant abiotic stress responses is still unclear. The TOR-mediated transcriptional regulation of genes encoding ribosomal proteins (RP) is a necessity under stress conditions for balanced growth and productivity in plants. The activation of SnRKs (sucrose non-fermenting-related kinases) and the inactivation of TOR signalling in abiotic stresses is in line with the accumulation of ABA and transcriptional activation of stress responsive genes. Autophagy is induced under abiotic stress conditions, which results in degradation of proteins and the release of amino acids, which might possibly induce phosphorylation of TOR and, hence, its activation. TOR signalling also has a role in regulating ABA biosynthesis for transcriptional regulation of stress-related genes. The switch between activation and inactivation of TOR by its phosphorylation and de-phosphorylation maintains balanced growth in response to stresses. In the present review, we discuss the important signalling pathways that are regulated by TOR and try to assess the relationship between TOR signalling and tolerance to abiotic stresses in plants. The review also discusses possible cross-talk between TOR and RP genes in response to abiotic stresses.
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Affiliation(s)
- A Bakshi
- Department of Plant Sciences, University of Hyderabad, Hyderabad, India
| | - M Moin
- Department of Biotechnology, Indian Institute of Rice Research, Hyderabad, India
| | - M S Madhav
- Department of Biotechnology, Indian Institute of Rice Research, Hyderabad, India
| | - P B Kirti
- Department of Plant Sciences, University of Hyderabad, Hyderabad, India
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135
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Barrada A, Djendli M, Desnos T, Mercier R, Robaglia C, Montané MH, Menand B. A TOR-YAK1 signaling axis controls cell cycle, meristem activity and plant growth in Arabidopsis. Development 2019; 146:dev.171298. [PMID: 30705074 DOI: 10.1242/dev.171298] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 01/14/2019] [Indexed: 01/20/2023]
Abstract
TARGET OF RAPAMYCIN (TOR) is a conserved eukaryotic phosphatidylinositol-3-kinase-related kinase that plays a major role in regulating growth and metabolism in response to environment in plants. We performed a genetic screen for Arabidopsis ethylmethane sulfonate mutants resistant to the ATP-competitive TOR inhibitor AZD-8055 to identify new components of the plant TOR pathway. We found that loss-of-function mutants of the DYRK (dual specificity tyrosine phosphorylation regulated kinase)/YAK1 kinase are resistant to AZD-8055 and, reciprocally, that YAK1 overexpressors are hypersensitive to AZD-8055. Significantly, these phenotypes were conditional on TOR inhibition, positioning YAK1 activity downstream of TOR. We further show that the ATP-competitive DYRK1A inhibitor pINDY phenocopies YAK1 loss of function. Microscopy analysis revealed that YAK1 functions to repress meristem size and induce differentiation. We show that YAK1 represses cyclin expression in the different zones of the root meristem and that YAK1 is essential for TOR-dependent transcriptional regulation of the plant-specific SIAMESE-RELATED (SMR) cyclin-dependent kinase inhibitors in both meristematic and differentiating root cells. Thus, YAK1 is a major regulator of meristem activity and cell differentiation downstream of TOR.
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Affiliation(s)
- Adam Barrada
- Aix Marseille Université, CEA, CNRS, BIAM, Laboratoire de Génétique et Biophysique des Plantes, Marseille, France F-13009
| | - Meriem Djendli
- Aix Marseille Université, CEA, CNRS, BIAM, Laboratoire de Génétique et Biophysique des Plantes, Marseille, France F-13009
| | - Thierry Desnos
- Aix Marseille Univ, CEA, CNRS, BIAM, Laboratoire de Biologie du Développement des Plantes, Saint Paul-Lez-Durance, France F-13108
| | - Raphael Mercier
- Institut Jean-Pierre Bourgin (IJPB), Institut National de la Recherche Agronomique, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
| | - Christophe Robaglia
- Aix Marseille Université, CEA, CNRS, BIAM, Laboratoire de Génétique et Biophysique des Plantes, Marseille, France F-13009
| | - Marie-Hélène Montané
- Aix Marseille Université, CEA, CNRS, BIAM, Laboratoire de Génétique et Biophysique des Plantes, Marseille, France F-13009
| | - Benoît Menand
- Aix Marseille Université, CEA, CNRS, BIAM, Laboratoire de Génétique et Biophysique des Plantes, Marseille, France F-13009
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136
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Wang Y, Cao JJ, Wang KX, Xia XJ, Shi K, Zhou YH, Yu JQ, Zhou J. BZR1 Mediates Brassinosteroid-Induced Autophagy and Nitrogen Starvation in Tomato. PLANT PHYSIOLOGY 2019; 179:671-685. [PMID: 30482787 PMCID: PMC6426427 DOI: 10.1104/pp.18.01028] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 11/13/2018] [Indexed: 05/10/2023]
Abstract
Autophagy, an innate cellular destructive mechanism, plays crucial roles in plant development and responses to stress. Autophagy is known to be stimulated or suppressed by multiple molecular processes, but the role of phytohormone signaling in autophagy is unclear. Here, we demonstrate that the transcripts of autophagy-related genes (ATGs) and the formation of autophagosomes are triggered by enhanced levels of brassinosteroid (BR). Furthermore, the BR-activated transcription factor brassinazole-resistant1 (BZR1), a positive regulator of the BR signaling pathway, is involved in BR-induced autophagy. Treatment with BR enhanced the formation of autophagosomes and the transcripts of ATGs in BZR1-overexpressing plants, while the effects of BR were compromised in BZR1-silenced plants. Yeast one-hybrid analysis and chromatin immunoprecipitation coupled with quantitative polymerase chain reaction revealed that BZR1 bound to the promoters of ATG2 and ATG6 The BR-induced formation of autophagosomes decreased in ATG2- and ATG6-silenced plants. Moreover, exogenous application of BR enhanced chlorophyll content and autophagosome formation and decreased the accumulation of ubiquitinated proteins under nitrogen starvation. Leaf chlorosis and chlorophyll degradation were exacerbated in BZR1-silenced plants and the BR biosynthetic mutant d^im but were alleviated in BZR1- and BZR1-1D-overexpressing plants under nitrogen starvation. Meanwhile, nitrogen starvation-induced expression of ATGs and autophagosome formation were compromised in both BZR1-silenced and d^im plants but were increased in BZR1- and BZR1-1D-overexpressing plants. Taken together, our results suggest that BZR1-dependent BR signaling up-regulates the expression of ATGs and autophagosome formation, which plays a critical role in the plant response to nitrogen starvation in tomato (Solanum lycopersicum).
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Affiliation(s)
- Yu Wang
- Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Jia-Jian Cao
- Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou 310058, China
| | - Kai-Xin Wang
- Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou 310058, China
| | - Xiao-Jian Xia
- Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou 310058, China
| | - Kai Shi
- Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou 310058, China
| | - Yan-Hong Zhou
- Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou 310058, China
| | - Jing-Quan Yu
- Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Horticultural Plants Growth, Development, and Quality Improvement, Agricultural Ministry of China, Hangzhou 310058, China
| | - Jie Zhou
- Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou 310058, China
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137
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Asad MAU, Zakari SA, Zhao Q, Zhou L, Ye Y, Cheng F. Abiotic Stresses Intervene with ABA Signaling to Induce Destructive Metabolic Pathways Leading to Death: Premature Leaf Senescence in Plants. Int J Mol Sci 2019; 20:E256. [PMID: 30634648 PMCID: PMC6359161 DOI: 10.3390/ijms20020256] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 12/27/2018] [Accepted: 12/28/2018] [Indexed: 12/19/2022] Open
Abstract
Abiotic stresses trigger premature leaf senescence by affecting some endogenous factors, which is an important limitation for plant growth and grain yield. Among these endogenous factors that regulate leaf senescence, abscisic acid (ABA) works as a link between the oxidase damage of cellular structure and signal molecules responding to abiotic stress during leaf senescence. Considering the importance of ABA, we collect the latest findings related to ABA biosynthesis, ABA signaling, and its inhibitory effect on chloroplast structure destruction, chlorophyll (Chl) degradation, and photosynthesis reduction. Post-translational changes in leaf senescence end with the exhaustion of nutrients, yellowing of leaves, and death of senescent tissues. In this article, we review the literature on the ABA-inducing leaf senescence mechanism in rice and Arabidopsis starting from ABA synthesis, transport, signaling receptors, and catabolism. We also predict the future outcomes of investigations related to other plants. Before changes in translation occur, ABA signaling that mediates the expression of NYC, bZIP, and WRKY transcription factors (TFs) has been investigated to explain the inducing effect on senescence-associated genes. Various factors related to calcium signaling, reactive oxygen species (ROS) production, and protein degradation are elaborated, and research gaps and potential prospects are presented. Examples of gene mutation conferring the delay or induction of leaf senescence are also described, and they may be helpful in understanding the inhibitory effect of abiotic stresses and effective measures to tolerate, minimize, or resist their inducing effect on leaf senescence.
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Affiliation(s)
- Muhammad Asad Ullah Asad
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Shamsu Ado Zakari
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Qian Zhao
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Lujian Zhou
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Yu Ye
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Fangmin Cheng
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
- Jiangsu Collaborative Innovation Centre for Modern Crop Production, Nanjing 210000, China.
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138
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Dong Y, Teleman AA, Jedmowski C, Wirtz M, Hell R. The Arabidopsis THADA homologue modulates TOR activity and cold acclimation. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21 Suppl 1:77-83. [PMID: 30098100 DOI: 10.1111/plb.12893] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 08/02/2018] [Indexed: 05/21/2023]
Abstract
Low temperature is one of the most important environmental factors that affect global survival of humans and animals and equally importantly the distribution of plants and crop productivity. Survival of metazoan cells under cold stress requires regulation of the sensor-kinase Target Of Rapamycin (TOR). TOR controls growth of eukaryotic cells by adjusting anabolic and catabolic metabolism. Previous studies identified the Thyroid Adenoma Associated (THADA) gene as the major effect locus by positive selection in the evolution of modern human adapted to cold. Here we investigate the role of THADA in TOR signaling and cold acclimation of plants. We applied BLAST searches and homology modeling to identify the AtTHADA (AT3G55160) in Arabidopsis thaliana as the highly probable orthologue protein. Reverse genetics approaches were combined with immunological detection of TOR activity and metabolite profiling to address the role of the TOR and THADA for growth regulation and cold acclimation. Depletion of the AtTHADA gene caused complete or partial loss of full-length mRNA, respectively, and significant retardation of growth under non-stressed conditions. Furthermore, depletion of AtTHADA caused hypersensitivity towards low-temperatures. Atthada displayed a lowered energy charge. This went along with decreased TOR activity, which offers a molecular explanation for the slow growth phenotype of Atthada. Finally, we used TOR RNAi lines to identify the de-regulation of TOR activity as one determinant for sensitivity towards low-temperatures. Taken together our results provide evidence for a conserved function of THADA in cold acclimation of eukaryotes and suggest that cold acclimation in plants requires regulation of TOR.
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Affiliation(s)
- Y Dong
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany
| | - A A Teleman
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - M Wirtz
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany
| | - R Hell
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany
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Gruszka D. Crosstalk of the Brassinosteroid Signalosome with Phytohormonal and Stress Signaling Components Maintains a Balance between the Processes of Growth and Stress Tolerance. Int J Mol Sci 2018; 19:ijms19092675. [PMID: 30205610 PMCID: PMC6163518 DOI: 10.3390/ijms19092675] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 08/22/2018] [Accepted: 09/07/2018] [Indexed: 12/25/2022] Open
Abstract
Brassinosteroids (BRs) are a class of phytohormones, which regulate various processes during plant life cycle. Intensive studies conducted with genetic, physiological and molecular approaches allowed identification of various components participating in the BR signaling—from the ligand perception, through cytoplasmic signal transduction, up to the BR-dependent gene expression, which is regulated by transcription factors and chromatin modifying enzymes. The identification of new components of the BR signaling is an ongoing process, however an emerging view of the BR signalosome indicates that this process is interconnected at various stages with other metabolic pathways. The signaling crosstalk is mediated by the BR signaling proteins, which function as components of the transmembrane BR receptor, by a cytoplasmic kinase playing a role of the major negative regulator of the BR signaling, and by the transcription factors, which regulate the BR-dependent gene expression and form a complicated regulatory system. This molecular network of interdependencies allows a balance in homeostasis of various phytohormones to be maintained. Moreover, the components of the BR signalosome interact with factors regulating plant reactions to environmental cues and stress conditions. This intricate network of interactions enables a rapid adaptation of plant metabolism to constantly changing environmental conditions.
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Affiliation(s)
- Damian Gruszka
- Department of Genetics, Faculty of Biology and Environment Protection, University of Silesia, Jagiellonska 28, 40-032 Katowice, Poland.
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140
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Zhang Y, Zhang Y, McFarlane HE, Obata T, Richter AS, Lohse M, Grimm B, Persson S, Fernie AR, Giavalisco P. Inhibition of TOR Represses Nutrient Consumption, Which Improves Greening after Extended Periods of Etiolation. PLANT PHYSIOLOGY 2018; 178:101-117. [PMID: 30049747 PMCID: PMC6130015 DOI: 10.1104/pp.18.00684] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 07/15/2018] [Indexed: 05/08/2023]
Abstract
Upon illumination, etiolated seedlings experience a transition from heterotrophic to photoautotrophic growth. During this process, the tetrapyrrole biosynthesis pathway provides chlorophyll for photosynthesis. This pathway has to be tightly controlled to prevent the accumulation of photoreactive metabolites and to provide stoichiometric amounts of chlorophyll for its incorporation into photosynthetic protein complexes. Therefore, plants have evolved regulatory mechanisms to synchronize the biosynthesis of chlorophyll and chlorophyll-binding proteins. Two phytochrome-interacting factors (PIF1 and PIF3) and the DELLA proteins, which are controlled by the gibberellin pathway, are key regulators of this process. Here, we show that impairment of TARGET OF RAPAMYCIN (TOR) activity in Arabidopsis (Arabidopsis thaliana), either by mutation of the TOR complex component RAPTOR1B or by treatment with TOR inhibitors, leads to a significantly reduced accumulation of the photoreactive chlorophyll precursor protochlorophyllide in darkness but an increased greening rate of etiolated seedlings after exposure to light. Detailed profiling of metabolic, transcriptomic, and physiological parameters revealed that the TOR-repressed lines not only grow slower, they grow in a nutrient-saving mode, which allows them to resist longer periods of low nutrient availability. Our results also indicated that RAPTOR1B acts upstream of the gibberellin-DELLA pathway and its mutation complements the repressed greening phenotype of pif1 and pif3 after etiolation.
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Affiliation(s)
- Yi Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Youjun Zhang
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
- Center of Plant System Biology and Biotechnology, 4000 Plovdiv, Bulgaria
| | - Heather E McFarlane
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
- School of Biosciences, University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia
| | - Toshihiro Obata
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
- Institute of Agriculture and Natural Resources, University of Nebraska, Lincoln, Nebraska 68588
| | - Andreas S Richter
- Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, Institut für Biologie, AG Pflanzenphysiologie, 10115 Berlin, Germany
| | - Mark Lohse
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
- Targenomix, 14476 Potsdam, Germany
| | - Bernhard Grimm
- Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, Institut für Biologie, AG Pflanzenphysiologie, 10115 Berlin, Germany
| | - Staffan Persson
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
- School of Biosciences, University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
- Center of Plant System Biology and Biotechnology, 4000 Plovdiv, Bulgaria
| | - Patrick Giavalisco
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
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141
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Abstract
Target of rapamycin (TOR) is an evolutionarily conserved protein kinase that plays a central role in both plants and animals, despite their distinct developmental programs and survival strategies. Indeed, TOR integrates nutrient, energy, hormone, growth factor and environmental inputs to control proliferation, growth and metabolism in diverse multicellular organisms. Here, we compare the molecular composition, upstream regulators and downstream signaling relays of TOR complexes in plants and animals. We also explore and discuss the pivotal functions of TOR signaling in basic cellular processes, such as translation, cell division and stem/progenitor cell regulation during plant development.
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Affiliation(s)
- Lin Shi
- Department of Molecular Biology and Centre for Computational and Integrative Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Yue Wu
- Department of Molecular Biology and Centre for Computational and Integrative Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Jen Sheen
- Department of Molecular Biology and Centre for Computational and Integrative Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
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142
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BRI1 and BAK1 interact with G proteins and regulate sugar-responsive growth and development in Arabidopsis. Nat Commun 2018; 9:1522. [PMID: 29670153 PMCID: PMC5906681 DOI: 10.1038/s41467-018-03884-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/20/2018] [Indexed: 12/24/2022] Open
Abstract
Sugars function as signal molecules to regulate growth, development, and gene expression in plants, yeasts, and animals. A coordination of sugar availability with phytohormone signals is crucial for plant growth and development. The molecular link between sugar availability and hormone-dependent plant growth are largely unknown. Here we report that BRI1 and BAK1 are involved in sugar-responsive growth and development. Glucose influences the physical interactions and phosphorylations of BRI1 and BAK1 in a concentration-dependent manner. BRI1 and BAK1 physically interact with G proteins that are essential for mediating sugar signaling. Biochemical data show that BRI1 can phosphorylate G protein β subunit and γ subunits, and BAK1 can phosphorylate G protein γ subunits. Genetic analyses suggest that BRI1 and BAK1 function in a common pathway with G-protein subunits to regulate sugar responses. Thus, our findings reveal an important genetic and molecular mechanism by which BR receptors associate with G proteins to regulate sugar-responsive growth and development. G-proteins regulate sugar-responsive growth in plants. Here the authors show that brassinosteroid (BR) signaling is also involved in sugar responses and present evidence that the BR receptor BRI1 and its co-receptor BAK1 can phosphorylate G-protein subunits to regulate sugar signaling in Arabidopsis.
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143
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The brassinosteroid-regulated transcription factors BZR1/BES1 function as a coordinator in multisignal-regulated plant growth. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:561-571. [PMID: 29673687 DOI: 10.1016/j.bbagrm.2018.04.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 04/06/2018] [Accepted: 04/06/2018] [Indexed: 11/24/2022]
Abstract
BZR1 and BES1 are key transcription factors of brassinosteroid (BR) signaling and represent the integration node of numerous signaling cascades. Their direct target genes have been identified, and BZR1/BES1-DNA interactions have been experimentally verified. Importantly, BZR1/BES1 also integrate different growth and development events via direct protein-protein interactions. For instance, DELLAs, PIFs, ARF6, and PKL, all directly interact with BZR1/BES1, forming a BZR1/BES1-centered regulatory network to coordinate cell elongation. By dissecting various BZR1/BES1-mediated BR responses, the concept that BZR1/BES1 act as an integration hub in multisignal-regulated plant growth and development was developed. The regulation of BZR1/BES1 is dynamic and multifaceted, including phosphorylation status, activity, and stability. Moreover, certain epigenetic modification mechanisms are involved in BZR1/BES1's regulation of gene expression. Herein, we review recent advances in BZR1/BES1-mediated molecular connections between BR and other pathways, highlighting the central role of the BZR1/BES1 interactome in optimizing plant growth and development.
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144
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Melatonin Alleviates High Temperature-Induced Pollen Abortion in Solanum lycopersicum. Molecules 2018; 23:molecules23020386. [PMID: 29439470 PMCID: PMC6017144 DOI: 10.3390/molecules23020386] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 12/21/2022] Open
Abstract
Melatonin is a pleiotropic signal molecule that plays critical roles in regulating plant growth and development, as well as providing physiological protections against various environmental stresses. Nonetheless, the mechanisms for melatonin-mediated pollen thermotolerance remain largely unknown. In this study, we report that irrigation treatment with melatonin (20 µM) effectively ameliorated high temperature-induced inactivation of pollen and inhibition of pollen germination in tomato (Solanum lycopersicum) plants. Melatonin alleviated reactive oxygen species production in tomato anthers under high temperature by the up-regulation of the transcription and activities of several antioxidant enzymes. Transmission electron micrograph results showed that high temperature-induced pollen abortion is associated with a premature degeneration of the tapetum cells and the formation of defective pollen grains with degenerated nuclei at the early uninuclear microspore stage, whilst melatonin protected degradation of organelles by enhancing the expression of heat shock protein genes to refold unfolded proteins and the expression of autophagy-related genes and formation of autophagosomes to degrade denatured proteins. These findings suggest a novel function of melatonin to protect pollen activity under high temperature and support the potential effects of melatonin on reproductive development of plants.
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145
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Krahmer J, Ganpudi A, Abbas A, Romanowski A, Halliday KJ. Phytochrome, Carbon Sensing, Metabolism, and Plant Growth Plasticity. PLANT PHYSIOLOGY 2018; 176:1039-1048. [PMID: 29254984 PMCID: PMC5813586 DOI: 10.1104/pp.17.01437] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 12/11/2017] [Indexed: 05/05/2023]
Abstract
Phytochrome signaling controls biomass accumulation, growth plasticity, and metabolism.
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Affiliation(s)
- Johanna Krahmer
- Institute for Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Ashwin Ganpudi
- Institute for Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Ammad Abbas
- Institute for Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Andrés Romanowski
- Institute for Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Karen J Halliday
- Institute for Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
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146
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Schepetilnikov M, Ryabova LA. Recent Discoveries on the Role of TOR (Target of Rapamycin) Signaling in Translation in Plants. PLANT PHYSIOLOGY 2018; 176:1095-1105. [PMID: 29122989 PMCID: PMC5813564 DOI: 10.1104/pp.17.01243] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/09/2017] [Indexed: 05/18/2023]
Abstract
TOR signaling regulates plant translation via a specific translation initiation mechanism: reinitiation.
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Affiliation(s)
- Mikhail Schepetilnikov
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, UPR 2357, Université de Strasbourg, 67084 Strasbourg, France
| | - Lyubov A Ryabova
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, UPR 2357, Université de Strasbourg, 67084 Strasbourg, France
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147
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Simon NML, Kusakina J, Fernández-López Á, Chembath A, Belbin FE, Dodd AN. The Energy-Signaling Hub SnRK1 Is Important for Sucrose-Induced Hypocotyl Elongation. PLANT PHYSIOLOGY 2018; 176:1299-1310. [PMID: 29114081 PMCID: PMC5813536 DOI: 10.1104/pp.17.01395] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 11/05/2017] [Indexed: 05/18/2023]
Abstract
Emerging seedlings respond to environmental conditions such as light and temperature to optimize their establishment. Seedlings grow initially through elongation of the hypocotyl, which is regulated by signaling pathways that integrate environmental information to regulate seedling development. The hypocotyls of Arabidopsis (Arabidopsis thaliana) also elongate in response to sucrose. Here, we investigated the role of cellular sugar-sensing mechanisms in the elongation of hypocotyls in response to Suc. We focused upon the role of SnRK1, which is a sugar-signaling hub that regulates metabolism and transcription in response to cellular energy status. We also investigated the role of TPS1, which synthesizes the signaling sugar trehalose-6-P that is proposed to regulate SnRK1 activity. Under light/dark cycles, we found that Suc-induced hypocotyl elongation did not occur in tps1 mutants and overexpressors of KIN10 (AKIN10/SnRK1.1), a catalytic subunit of SnRK1. We demonstrate that the magnitude of Suc-induced hypocotyl elongation depends on the day length and light intensity. We identified roles for auxin and gibberellin signaling in Suc-induced hypocotyl elongation under short photoperiods. We found that Suc-induced hypocotyl elongation under light/dark cycles does not involve another proposed sugar sensor, HEXOKINASE1, or the circadian oscillator. Our study identifies novel roles for KIN10 and TPS1 in mediating a signal that underlies Suc-induced hypocotyl elongation in light/dark cycles.
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Affiliation(s)
- Noriane M L Simon
- School of Biological Sciences, University of Bristol, Life Sciences Building, Bristol BS8 1TQ, United Kingdom
| | - Jelena Kusakina
- Cabot Institute, University of Bristol, Bristol BS8 1UJ, United Kingdom
| | - Ángela Fernández-López
- School of Biological Sciences, University of Bristol, Life Sciences Building, Bristol BS8 1TQ, United Kingdom
| | | | - Fiona E Belbin
- School of Biological Sciences, University of Bristol, Life Sciences Building, Bristol BS8 1TQ, United Kingdom
| | - Antony N Dodd
- School of Biological Sciences, University of Bristol, Life Sciences Building, Bristol BS8 1TQ, United Kingdom
- Cabot Institute, University of Bristol, Bristol BS8 1UJ, United Kingdom
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148
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Simon NML, Sawkins E, Dodd AN. Involvement of the SnRK1 subunit KIN10 in sucrose-induced hypocotyl elongation. PLANT SIGNALING & BEHAVIOR 2018; 13:e1457913. [PMID: 29584583 PMCID: PMC6110359 DOI: 10.1080/15592324.2018.1457913] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/20/2018] [Accepted: 03/21/2018] [Indexed: 05/21/2023]
Abstract
A mechanism participating in energy sensing and signalling in plants involves the regulation of sucrose non-fermenting1 (Snf1)-related protein kinase 1 (SnRK1) activity in response to sugar availability. SnRK1 is thought to regulate the activity of both metabolic enzymes and transcription factors in response to changes in energy availability, with trehalose-6-phospate functioning as a signalling sugar that suppresses SnRK1 activity under sugar-replete conditions. Sucrose supplementation increases the elongation of hypocotyls of developing Arabidopsis seedlings, and this response to sucrose involves both the SnRK1 subunit KIN10 and also TREHALOSE-6-PHOSPHATE SYNTHASE1 (TPS1). Here, we measured sucrose-induced hypocotyl elongation in two insertional mutants of KIN10 (akin10 and akin10-2). Under short photoperiods, sucrose supplementation caused great proportional hypocotyl elongation in these KIN10 mutants compared with the wild type, and these mutants had shorter hypocotyls than the wild type in the absence of sucrose supplementation. One interpretation is that SnRK1 activity might suppress hypocotyl elongation in the presence of sucrose, because KIN10 overexpression inhibits sucrose-induced hypocotyl elongation and akin10 mutants enhance sucrose-induced hypocotyl elongation.
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Affiliation(s)
- Noriane M. L. Simon
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, U.K.
| | - Ellie Sawkins
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, U.K.
| | - Antony N. Dodd
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, U.K.
- CONTACT Antony N. Dodd School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, U.K.
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149
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De Vleesschauwer D, Filipe O, Hoffman G, Seifi HS, Haeck A, Canlas P, Van Bockhaven J, De Waele E, Demeestere K, Ronald P, Hofte M. Target of rapamycin signaling orchestrates growth-defense trade-offs in plants. THE NEW PHYTOLOGIST 2018; 217:305-319. [PMID: 28905991 PMCID: PMC5711548 DOI: 10.1111/nph.14785] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 08/09/2017] [Indexed: 05/18/2023]
Abstract
Plant defense to microbial pathogens is often accompanied by significant growth inhibition. How plants merge immune system function with normal growth and development is still poorly understood. Here, we investigated the role of target of rapamycin (TOR), an evolutionary conserved serine/threonine kinase, in the plant defense response. We used rice as a model system and applied a combination of chemical, genetic, genomic and cell-based analyses. We demonstrate that ectopic expression of TOR and Raptor (regulatory-associated protein of mTOR), a protein previously demonstrated to interact with TOR in Arabidopsis, positively regulates growth and development in rice. Transcriptome analysis of rice cells treated with the TOR-specific inhibitor rapamycin revealed that TOR not only dictates transcriptional reprogramming of extensive gene sets involved in central and secondary metabolism, cell cycle and transcription, but also suppresses many defense-related genes. TOR overexpression lines displayed increased susceptibility to both bacterial and fungal pathogens, whereas plants with reduced TOR signaling displayed enhanced resistance. Finally, we found that TOR antagonizes the action of the classic defense hormones salicylic acid and jasmonic acid. Together, these results indicate that TOR acts as a molecular switch for the activation of cell proliferation and plant growth at the expense of cellular immunity.
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Affiliation(s)
- David De Vleesschauwer
- Laboratory of Phytopathology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Osvaldo Filipe
- Laboratory of Phytopathology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Gena Hoffman
- Department of Plant Pathology and the Genome Center, University of California, Davis, CA, 95616, USA
| | - Hamed Soren Seifi
- Laboratory of Phytopathology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Ashley Haeck
- Research Group EnVOC, Department of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Patrick Canlas
- Department of Plant Pathology and the Genome Center, University of California, Davis, CA, 95616, USA
| | - Jonas Van Bockhaven
- Laboratory of Phytopathology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Evelien De Waele
- Laboratory of Phytopathology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Kristof Demeestere
- Research Group EnVOC, Department of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Pamela Ronald
- Department of Plant Pathology and the Genome Center, University of California, Davis, CA, 95616, USA
- Joint Bioenergy Institute, Emeryville, CA, 94608, USA
| | - Monica Hofte
- Laboratory of Phytopathology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
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150
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Reciprocal Regulation of the TOR Kinase and ABA Receptor Balances Plant Growth and Stress Response. Mol Cell 2017; 69:100-112.e6. [PMID: 29290610 DOI: 10.1016/j.molcel.2017.12.002] [Citation(s) in RCA: 298] [Impact Index Per Article: 42.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 07/19/2017] [Accepted: 12/01/2017] [Indexed: 01/08/2023]
Abstract
As sessile organisms, plants must adapt to variations in the environment. Environmental stress triggers various responses, including growth inhibition, mediated by the plant hormone abscisic acid (ABA). The mechanisms that integrate stress responses with growth are poorly understood. Here, we discovered that the Target of Rapamycin (TOR) kinase phosphorylates PYL ABA receptors at a conserved serine residue to prevent activation of the stress response in unstressed plants. This phosphorylation disrupts PYL association with ABA and with PP2C phosphatase effectors, leading to inactivation of SnRK2 kinases. Under stress, ABA-activated SnRK2s phosphorylate Raptor, a component of the TOR complex, triggering TOR complex dissociation and inhibition. Thus, TOR signaling represses ABA signaling and stress responses in unstressed conditions, whereas ABA signaling represses TOR signaling and growth during times of stress. Plants utilize this conserved phospho-regulatory feedback mechanism to optimize the balance of growth and stress responses.
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