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Haq SIU, Shang J, Xie H, Qiu QS. Roles of TOR signaling in nutrient deprivation and abiotic stress. JOURNAL OF PLANT PHYSIOLOGY 2022; 274:153716. [PMID: 35597106 DOI: 10.1016/j.jplph.2022.153716] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/25/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
In living organisms, nutrient, energy, and environmental stimuli sensing and signaling are considered as the most primordial regulatory networks governing growth and development. Target of Rapamycin (TOR) is a diversified Serine/Threonine protein kinase existing in all eukaryotes that regulates distinct salient growth and developmental signaling pathways. TOR signaling acts as a central hub in plants that allows a variety of nutrients, energy, hormones, and environmental stimuli to be integrated. TOR is activated by several nutrients and promotes energy-consuming processes such as cell division, protein translation, mRNA translation and ribosome biogenesis. We summarized the recent findings on the TOR function in regulating the dynamic networks of nutrients, including sugar, sulfur, nitrogen, carbon, phosphorus, potassium, and amino acids. TOR's role in abiotic stress was discussed, in which TOR orchestrating stress signaling, including heat, cold, salt, and osmotic stress, to regulate transcriptional and metabolic reprogramming, as well as growth and development. The interconnections between TOR and SnRK1 kinase were discussed in controlling nutrient deprivation and abiotic stress.
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Affiliation(s)
- Syed Inzimam Ul Haq
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China
| | - Jun Shang
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, Qinghai, 810000, China; Qinghai Provincial Key Laboratory of Medicinal Plant and Animal Resources of Qinghai-Tibet Plateau, Xining, Qinghai, 810008, China
| | - Huichun Xie
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, Qinghai, 810000, China; Qinghai Provincial Key Laboratory of Medicinal Plant and Animal Resources of Qinghai-Tibet Plateau, Xining, Qinghai, 810008, China
| | - Quan-Sheng Qiu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China; Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, Qinghai, 810000, China.
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Roy B, von Arnim AG. Translational Regulation of Cytoplasmic mRNAs. THE ARABIDOPSIS BOOK 2013; 11:e0165. [PMID: 23908601 PMCID: PMC3727577 DOI: 10.1199/tab.0165] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Translation of the coding potential of a messenger RNA into a protein molecule is a fundamental process in all living cells and consumes a large fraction of metabolites and energy resources in growing cells. Moreover, translation has emerged as an important control point in the regulation of gene expression. At the level of gene regulation, translational control is utilized to support the specific life histories of plants, in particular their responses to the abiotic environment and to metabolites. This review summarizes the diversity of translational control mechanisms in the plant cytoplasm, focusing on specific cases where mechanisms of translational control have evolved to complement or eclipse other levels of gene regulation. We begin by introducing essential features of the translation apparatus. We summarize early evidence for translational control from the pre-Arabidopsis era. Next, we review evidence for translation control in response to stress, to metabolites, and in development. The following section emphasizes RNA sequence elements and biochemical processes that regulate translation. We close with a chapter on the role of signaling pathways that impinge on translation.
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Affiliation(s)
- Bijoyita Roy
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996-0840
- Current address: University of Massachussetts Medical School, Worcester, MA 01655-0122, USA
| | - Albrecht G. von Arnim
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996-0840
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN 37996-0840
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Robaglia C, Thomas M, Meyer C. Sensing nutrient and energy status by SnRK1 and TOR kinases. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:301-7. [PMID: 22305521 DOI: 10.1016/j.pbi.2012.01.012] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 01/10/2012] [Accepted: 01/11/2012] [Indexed: 05/18/2023]
Abstract
The perception of nutrient and energy levels inside and outside the cell is crucial to adjust growth and metabolism to available resources. The signaling pathways centered on the conserved TOR and SnRK1/Snf1/AMPK kinases have crucial and numerous roles in nutrient and energy sensing and in translating this information into metabolic and developmental adaptations. In plants evidence is mounting that, like in other eukaryotes, these signaling pathways have pivotal and antagonistic roles in connecting external or intracellular cues to many biological processes, including ribosome biogenesis, regulation of translation, cell division, accumulation of reserves and autophagy. Data on the plant TOR pathway have been hitherto rather scarce but recent findings have shed new light on its roles in plants. Moreover, the distinctive energy metabolism of photosynthetic organisms may reveal new features of these ancestral eukaryotic signaling elements.
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Affiliation(s)
- Christophe Robaglia
- Laboratoire de Génétique et Biophysique des Plantes, UMR 7265, CEA/CNRS, Aix Marseille Université, Faculté des Sciences de Luminy, 163 Avenue de Luminy, Marseille, France
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Shertz CA, Bastidas RJ, Li W, Heitman J, Cardenas ME. Conservation, duplication, and loss of the Tor signaling pathway in the fungal kingdom. BMC Genomics 2010; 11:510. [PMID: 20863387 PMCID: PMC2997006 DOI: 10.1186/1471-2164-11-510] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Accepted: 09/23/2010] [Indexed: 11/10/2022] Open
Abstract
Background The nutrient-sensing Tor pathway governs cell growth and is conserved in nearly all eukaryotic organisms from unicellular yeasts to multicellular organisms, including humans. Tor is the target of the immunosuppressive drug rapamycin, which in complex with the prolyl isomerase FKBP12 inhibits Tor functions. Rapamycin is a gold standard drug for organ transplant recipients that was approved by the FDA in 1999 and is finding additional clinical indications as a chemotherapeutic and antiproliferative agent. Capitalizing on the plethora of recently sequenced genomes we have conducted comparative genomic studies to annotate the Tor pathway throughout the fungal kingdom and related unicellular opisthokonts, including Monosiga brevicollis, Salpingoeca rosetta, and Capsaspora owczarzaki. Results Interestingly, the Tor signaling cascade is absent in three microsporidian species with available genome sequences, the only known instance of a eukaryotic group lacking this conserved pathway. The microsporidia are obligate intracellular pathogens with highly reduced genomes, and we hypothesize that they lost the Tor pathway as they adapted and streamlined their genomes for intracellular growth in a nutrient-rich environment. Two TOR paralogs are present in several fungal species as a result of either a whole genome duplication or independent gene/segmental duplication events. One such event was identified in the amphibian pathogen Batrachochytrium dendrobatidis, a chytrid responsible for worldwide global amphibian declines and extinctions. Conclusions The repeated independent duplications of the TOR gene in the fungal kingdom might reflect selective pressure acting upon this kinase that populates two proteinaceous complexes with different cellular roles. These comparative genomic analyses illustrate the evolutionary trajectory of a central nutrient-sensing cascade that enables diverse eukaryotic organisms to respond to their natural environments.
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Affiliation(s)
- Cecelia A Shertz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
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Reinbothe C, Springer A, Samol I, Reinbothe S. Plant oxylipins: role of jasmonic acid during programmed cell death, defence and leaf senescence. FEBS J 2009; 276:4666-81. [PMID: 19663906 DOI: 10.1111/j.1742-4658.2009.07193.x] [Citation(s) in RCA: 158] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Plants are continuously challenged by a variety of abiotic and biotic cues. To deter feeding insects, nematodes and fungal and bacterial pathogens, plants have evolved a plethora of defence strategies. A central player in many of these defence responses is jasmonic acid. It is the aim of this minireview to summarize recent findings that highlight the role of jasmonic acid during programmed cell death, plant defence and leaf senescence.
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Singlet oxygen-dependent translational control in the tigrina-d.12 mutant of barley. Proc Natl Acad Sci U S A 2009; 106:13112-7. [PMID: 19620736 DOI: 10.1073/pnas.0903522106] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The tigrina (tig)-d.12 mutant of barley is impaired in the negative control limiting excess protochlorophyllide (Pchlide) accumulation in the dark. Upon illumination, Pchlide operates as photosensitizer and triggers singlet oxygen production and cell death. Here, we show that both Pchlide and singlet oxygen operate as signals that control gene expression and metabolite accumulation in tig-d.12 plants. In vivo labeling, Northern blotting, polysome profiling, and protein gel blot analyses revealed a selective suppression of synthesis of the small and large subunits of ribulose-1,5-bisphosphate carboxylase/oxygenase (RBCSs and RBCLs), the major light-harvesting chlorophyll a/b-binding protein of photosystem II (LHCB2), as well as other chlorophyll-binding proteins, in response to singlet oxygen. In part, these effects were caused by an arrest in translation initiation of photosynthetic transcripts at 80S cytoplasmic ribosomes. The observed changes in translation correlated with a decline in the phosphorylation level of ribosomal protein S6. At later stages, ribosome dissociation occurred. Together, our results identify translation as a major target of singlet oxygen-dependent growth control and cell death in higher plants.
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Krizek BA. Making bigger plants: key regulators of final organ size. CURRENT OPINION IN PLANT BIOLOGY 2009; 12:17-22. [PMID: 18951836 DOI: 10.1016/j.pbi.2008.09.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2008] [Accepted: 09/11/2008] [Indexed: 05/18/2023]
Abstract
Organ growth in plants is controlled by both genetic factors and environmental inputs. Recent progress has been made in identifying genetic determinants of final organ size and in characterizing a pathway that may link organ growth with environmental conditions. Some identified growth regulatory factors act downstream of plant hormones, while others appear to be components of novel signaling pathways. Additional characterization of these proteins is needed before we can understand how growth-promoting and growth-restricting inputs are integrated to coordinate growth within a developing organ. Some parallels in the mechanisms used by plants and animals to regulate organ size are suggested by the identification of KLUH, a noncell-autonomous regulator of organ growth, and by similarities in the target of rapamycin (TOR)-signaling pathway.
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Affiliation(s)
- Beth A Krizek
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
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Deprost D, Yao L, Sormani R, Moreau M, Leterreux G, Nicolaï M, Bedu M, Robaglia C, Meyer C. The Arabidopsis TOR kinase links plant growth, yield, stress resistance and mRNA translation. EMBO Rep 2007; 8:864-70. [PMID: 17721444 PMCID: PMC1973950 DOI: 10.1038/sj.embor.7401043] [Citation(s) in RCA: 357] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 07/03/2007] [Accepted: 07/04/2007] [Indexed: 11/09/2022] Open
Abstract
Plants, unlike animals, have plastic organ growth that is largely dependent on environmental information. However, so far, little is known about how this information is perceived and transduced into coherent growth and developmental decisions. Here, we report that the growth of Arabidopsis is positively correlated with the level of expression of the TARGET OF RAPAMYCIN (TOR) kinase. Diminished or augmented expression of the AtTOR gene results in a dose-dependent decrease or increase, respectively, in organ and cell size, seed production and resistance to osmotic stress. Strong downregulation of AtTOR expression by inducible RNA interference also leads to a post-germinative halt in growth and development, which phenocopies the action of the plant hormone abscisic acid, to an early senescence and to a reduction in the amount of translated messenger RNA. Thus, we propose that the AtTOR kinase is one of the contributors to the link between environmental cues and growth processes in plants.
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Affiliation(s)
- Dorothée Deprost
- Unité de Nutrition Azotée des Plantes, Institut Jean-Pierre Bourgin, INRA Versailles, Versailles 78000, France
| | - Lei Yao
- Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forest Sciences, PO Box 2449, Beijing 100097, China
- Laboratoire de Génétique et Biophysique des Plantes, CNRS-CEA-Université de la Méditerranée Faculté des Sciences de Luminy, 163 Avenue de Luminy, Marseille 13009, France
| | - Rodnay Sormani
- Laboratoire de Génétique et Biophysique des Plantes, CNRS-CEA-Université de la Méditerranée Faculté des Sciences de Luminy, 163 Avenue de Luminy, Marseille 13009, France
| | - Manon Moreau
- Unité de Nutrition Azotée des Plantes, Institut Jean-Pierre Bourgin, INRA Versailles, Versailles 78000, France
| | - Guillaume Leterreux
- Unité de Nutrition Azotée des Plantes, Institut Jean-Pierre Bourgin, INRA Versailles, Versailles 78000, France
| | - Maryse Nicolaï
- Laboratoire de Génétique et Biophysique des Plantes, CNRS-CEA-Université de la Méditerranée Faculté des Sciences de Luminy, 163 Avenue de Luminy, Marseille 13009, France
| | - Magali Bedu
- Unité de Nutrition Azotée des Plantes, Institut Jean-Pierre Bourgin, INRA Versailles, Versailles 78000, France
| | - Christophe Robaglia
- Laboratoire de Génétique et Biophysique des Plantes, CNRS-CEA-Université de la Méditerranée Faculté des Sciences de Luminy, 163 Avenue de Luminy, Marseille 13009, France
| | - Christian Meyer
- Unité de Nutrition Azotée des Plantes, Institut Jean-Pierre Bourgin, INRA Versailles, Versailles 78000, France
- Tel: +33 1 30 83 30 67; Fax: +33 1 30 83 30 96; E-mail:
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Abstract
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that controls many aspects of cellular physiology, including transcription, translation, cell size, cytoskeletal organization and autophagy. Recent advances in the mTOR signaling field have found that mTOR exists in two heteromeric complexes, mTORC1 and mTORC2. The activity of mTORC1 is regulated by the integration of many signals, including growth factors, insulin, nutrients, energy availability and cellular stressors such as hypoxia, osmotic stress, reactive oxygen species and viral infection. In this review we highlight recent advances in the mTOR signaling field that relate to how the two mTOR complexes are regulated, and we discuss stress conditions linked to the mTOR signaling network that have not been extensively covered in other reviews. Given the diversity of signals that have been shown to impinge on mTOR, we also speculate on other signal-transduction pathways that may be linked to mTOR in the future.
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Affiliation(s)
- M N Corradetti
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.
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Ingram GC, Waites R. Keeping it together: co-ordinating plant growth. CURRENT OPINION IN PLANT BIOLOGY 2006; 9:12-20. [PMID: 16326130 DOI: 10.1016/j.pbi.2005.11.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2005] [Accepted: 11/23/2005] [Indexed: 05/05/2023]
Abstract
One of the most important demands of multicellularity is the co-ordination of cell proliferation and cell growth to allow the ultimate differentiation of functional organs and tissues. In plants, endogenously and exogenously generated developmental signals hone a basic patterning plan to the demands of a changing environment throughout the lifecycle. Recent advances have started to identify many signalling pathways and intermediates that are potentially implicated in controlling plant growth in response to developmentally important signals. These include pathways that are conserved in other eukaryotes, such as the Target Of Rapamycin (TOR) pathway and lipid signalling via S6-Kinases, as well as pathways that contain plant-specific elements, such as ERECTA-class receptor kinases and TCP-class transcription factors. Understanding how these elements are integrated to give co-ordinated growth remains one of the major challenges in plant biology.
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Affiliation(s)
- Gwyneth C Ingram
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3JR, UK.
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Robaglia C, Caranta C. Translation initiation factors: a weak link in plant RNA virus infection. TRENDS IN PLANT SCIENCE 2006; 11:40-5. [PMID: 16343979 DOI: 10.1016/j.tplants.2005.11.004] [Citation(s) in RCA: 275] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Revised: 10/11/2005] [Accepted: 11/25/2005] [Indexed: 05/05/2023]
Abstract
Recessive resistance genes against plant viruses have been recognized for a long time but their molecular nature has only recently been linked to components of the eukaryotic translation initiation complex. Translation initiation factors, and particularly the eIF4E and eIF4G protein families, were found to be essential determinants in the outcome of RNA virus infections. Viruses affected by these genes belong mainly to potyviruses; natural viral resistance mechanisms as well as mutagenesis analysis in Arabidopsis all converged to identify the same set of translation initiation factors. Their role in plant resistance against RNA viruses remains to be elucidated. Although the interaction with the protein synthesis machinery is probably a key element for successful RNA virus infection, other possible mechanisms will also be discussed.
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Affiliation(s)
- Christophe Robaglia
- Laboratoire de Génétique et Biophysique des Plantes, CEA-CNRS-Université Aix-Marseille II, Faculté des Sciences de Luminy, F-13009 Marseille, France.
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