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Avidan O, Martins MCM, Feil R, Lohse M, Giorgi FM, Schlereth A, Lunn JE, Stitt M. Direct and indirect responses of the Arabidopsis transcriptome to an induced increase in trehalose 6-phosphate. PLANT PHYSIOLOGY 2024; 196:409-431. [PMID: 38593032 PMCID: PMC11376379 DOI: 10.1093/plphys/kiae196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 03/08/2024] [Accepted: 03/13/2024] [Indexed: 04/11/2024]
Abstract
Trehalose 6-phosphate (Tre6P) is an essential signal metabolite that regulates the level of sucrose, linking growth and development to the metabolic status. We hypothesized that Tre6P plays a role in mediating the regulation of gene expression by sucrose. To test this, we performed transcriptomic profiling on Arabidopsis (Arabidopsis thaliana) plants that expressed a bacterial TREHALOSE 6-PHOSPHATE SYNTHASE (TPS) under the control of an ethanol-inducible promoter. Induction led to a 4-fold rise in Tre6P levels, a concomitant decrease in sucrose, significant changes (FDR ≤ 0.05) of over 13,000 transcripts, and 2-fold or larger changes of over 5,000 transcripts. Comparison with nine published responses to sugar availability allowed some of these changes to be linked to the rise in Tre6P, while others were probably due to lower sucrose or other indirect effects. Changes linked to Tre6P included repression of photosynthesis-related gene expression and induction of many growth-related processes including ribosome biogenesis. About 500 starvation-related genes are known to be induced by SUCROSE-NON-FERMENTING-1-RELATED KINASE 1 (SnRK1). They were largely repressed by Tre6P in a manner consistent with SnRK1 inhibition by Tre6P. SnRK1 also represses many genes that are involved in biosynthesis and growth. These responded to Tre6P in a more complex manner, pointing toward Tre6P interacting with other C-signaling pathways. Additionally, elevated Tre6P modified the expression of genes encoding regulatory subunits of the SnRK1 complex and TPS class II and FCS-LIKE ZINC FINGER proteins that are thought to modulate SnRK1 function and genes involved in circadian, TARGET OF RAPAMYCIN, light, abscisic acid, and other hormone signaling.
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Affiliation(s)
- Omri Avidan
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Marina C M Martins
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Regina Feil
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Marc Lohse
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Federico M Giorgi
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Armin Schlereth
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - John E Lunn
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
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2
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Nguyen E, Sosa JA, Cassidy KC, Berman AJ. Comparative analysis of the LARP1 C-terminal DM15 region through Coelomate evolution. PLoS One 2024; 19:e0308574. [PMID: 39190712 DOI: 10.1371/journal.pone.0308574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Accepted: 07/26/2024] [Indexed: 08/29/2024] Open
Abstract
TOR (target of rapamycin), a ubiquitous protein kinase central to cellular homeostasis maintenance, fundamentally regulates ribosome biogenesis in part by its target La-related protein 1 (LARP1). Among other target transcripts, LARP1 specifically binds TOP (terminal oligopyrimidine) mRNAs encoding all 80 ribosomal proteins in a TOR-dependent manner through its C-terminal region containing the DM15 module. Though the functional implications of the LARP1 interaction with target mRNAs is controversial, it is clear that the TOP-LARP1-TOR axis is critical to cellular health in humans. Its existence and role in evolutionarily divergent animals remain less understood. We focused our work on expanding our knowledge of the first arm of the axis: the connection between LARP1-DM15 and the 5' TOP motif. We show that the overall DM15 architecture observed in humans is conserved in fruit fly and zebrafish. Both adopt familiar curved arrangements of HEAT-like repeats that bind 5' TOP mRNAs on the same conserved surface, although molecular dynamics simulations suggest that the N-terminal fold of the fruit fly DM15 is predicted to be unstable and unfold. We demonstrate that each ortholog interacts with TOP sequences with varying affinities. Importantly, we determine that the ability of the DM15 region to bind some TOP sequences but not others might amount to the context of the RNA structure, rather than the ability of the module to recognize some sequences but not others. We propose that TOP mRNAs may retain similar secondary structures to regulate LARP1 DM15 recognition.
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Affiliation(s)
- Elaine Nguyen
- Biological Sciences, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Jahree A Sosa
- Biological Sciences, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Kevin C Cassidy
- BIOVIA, Dassault Systèmes, Waltham, MA, United States of America
| | - Andrea J Berman
- Biological Sciences, University of Pittsburgh, Pittsburgh, PA, United States of America
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3
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Boix M, Garcia-Rodriguez A, Castillo L, Miró B, Hamilton F, Tolak S, Pérez A, Monte-Bello C, Caldana C, Henriques R. 40S Ribosomal protein S6 kinase integrates daylength perception and growth regulation in Arabidopsis thaliana. PLANT PHYSIOLOGY 2024; 195:3039-3052. [PMID: 38701056 PMCID: PMC11288760 DOI: 10.1093/plphys/kiae254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 03/29/2024] [Accepted: 04/09/2024] [Indexed: 05/05/2024]
Abstract
Plant growth occurs via the interconnection of cell growth and proliferation in each organ following specific developmental and environmental cues. Therefore, different photoperiods result in distinct growth patterns due to the integration of light and circadian perception with specific Carbon (C) partitioning strategies. In addition, the TARGET OF RAPAMYCIN (TOR) kinase pathway is an ancestral signaling pathway that integrates nutrient information with translational control and growth regulation. Recent findings in Arabidopsis (Arabidopsis thaliana) have shown a mutual connection between the TOR pathway and the circadian clock. However, the mechanistical network underlying this interaction is mostly unknown. Here, we show that the conserved TOR target, the 40S ribosomal protein S6 kinase (S6K) is under circadian and photoperiod regulation both at the transcriptional and post-translational level. Total S6K (S6K1 and S6K2) and TOR-dependent phosphorylated-S6K protein levels were higher during the light period and decreased at dusk especially under short day conditions. Using chemical and genetic approaches, we found that the diel pattern of S6K accumulation results from 26S proteasome-dependent degradation and is altered in mutants lacking the circadian F-box protein ZEITLUPE (ZTL), further strengthening our hypothesis that S6K could incorporate metabolic signals via TOR, which are also under circadian regulation. Moreover, under short days when C/energy levels are limiting, changes in S6K1 protein levels affected starch, sucrose and glucose accumulation and consequently impacted root and rosette growth responses. In summary, we propose that S6K1 constitutes a missing molecular link where day-length perception, nutrient availability and TOR pathway activity converge to coordinate growth responses with environmental conditions.
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Affiliation(s)
- Marc Boix
- Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB, 08193 Barcelona, Spain
| | - Alba Garcia-Rodriguez
- Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB, 08193 Barcelona, Spain
| | - Laia Castillo
- Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB, 08193 Barcelona, Spain
| | - Bernat Miró
- Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB, 08193 Barcelona, Spain
| | - Ferga Hamilton
- School of Biological, Earth and Environmental Sciences, University College Cork, North Mall, Cork T23 N73K, Ireland
- Environmental Research Institute, University College Cork, Cork T23 XE10, Ireland
| | - Sanata Tolak
- School of Biological, Earth and Environmental Sciences, University College Cork, North Mall, Cork T23 N73K, Ireland
- Environmental Research Institute, University College Cork, Cork T23 XE10, Ireland
| | - Adrián Pérez
- Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB, 08193 Barcelona, Spain
| | | | - Camila Caldana
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany
| | - Rossana Henriques
- Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB, 08193 Barcelona, Spain
- School of Biological, Earth and Environmental Sciences, University College Cork, North Mall, Cork T23 N73K, Ireland
- Environmental Research Institute, University College Cork, Cork T23 XE10, Ireland
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4
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Lohmann J, Herzog O, Rosenzweig K, Weingartner M. Thermal adaptation in plants: understanding the dynamics of translation factors and condensates. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:4258-4273. [PMID: 38630631 DOI: 10.1093/jxb/erae171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 04/16/2024] [Indexed: 04/19/2024]
Abstract
Plants, as sessile organisms, face the crucial challenge of adjusting growth and development with ever-changing environmental conditions. Protein synthesis is the fundamental process that enables growth of all organisms. Since elevated temperature presents a substantial threat to protein stability and function, immediate adjustments of protein synthesis rates are necessary to circumvent accumulation of proteotoxic stress and to ensure survival. This review provides an overview of the mechanisms that control translation under high-temperature stress by the modification of components of the translation machinery in plants, and compares them to yeast and metazoa. Recent research also suggests an important role for cytoplasmic biomolecular condensates, named stress granules, in these processes. Current understanding of the role of stress granules in translational regulation and of the molecular processes associated with translation that might occur within stress granules is also discussed.
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Affiliation(s)
- Julia Lohmann
- Institute of Plant Sciences and Microbiology, University of Hamburg, Ohnhorststrasse 18, 22609 Hamburg, Germany
| | - Oliver Herzog
- Institute of Plant Sciences and Microbiology, University of Hamburg, Ohnhorststrasse 18, 22609 Hamburg, Germany
| | - Kristina Rosenzweig
- Institute of Plant Sciences and Microbiology, University of Hamburg, Ohnhorststrasse 18, 22609 Hamburg, Germany
| | - Magdalena Weingartner
- Institute of Plant Sciences and Microbiology, University of Hamburg, Ohnhorststrasse 18, 22609 Hamburg, Germany
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Artins A, Martins MCM, Meyer C, Fernie AR, Caldana C. Sensing and regulation of C and N metabolism - novel features and mechanisms of the TOR and SnRK1 signaling pathways. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:1268-1280. [PMID: 38349940 DOI: 10.1111/tpj.16684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/25/2024] [Accepted: 02/02/2024] [Indexed: 02/15/2024]
Abstract
Carbon (C) and nitrogen (N) metabolisms are tightly integrated to allow proper plant growth and development. Photosynthesis is dependent on N invested in chlorophylls, enzymes, and structural components of the photosynthetic machinery, while N uptake and assimilation rely on ATP, reducing equivalents, and C-skeletons provided by photosynthesis. The direct connection between N availability and photosynthetic efficiency allows the synthesis of precursors for all metabolites and building blocks in plants. Thus, the capacity to sense and respond to sudden changes in C and N availability is crucial for plant survival and is mediated by complex yet efficient signaling pathways such as TARGET OF RAPAMYCIN (TOR) and SUCROSE-NON-FERMENTING-1-RELATED PROTEIN KINASE 1 (SnRK1). In this review, we present recent advances in mechanisms involved in sensing C and N status as well as identifying current gaps in our understanding. We finally attempt to provide new perspectives and hypotheses on the interconnection of diverse signaling pathways that will allow us to understand the integration and orchestration of the major players governing the regulation of the CN balance.
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Affiliation(s)
- Anthony Artins
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Golm, Germany
| | - Marina C M Martins
- in Press - Scientific Consulting and Communication Services, 05089-030, São Paulo, São Paulo, Brazil
| | - Christian Meyer
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000, Versailles, France
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Golm, Germany
| | - Camila Caldana
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Golm, Germany
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Kong S, Zhu M, Scarpin MR, Pan D, Jia L, Martinez RE, Alamos S, Vadde BVL, Garcia HG, Qian SB, Brunkard JO, Roeder AHK. DRMY1 promotes robust morphogenesis by sustaining the translation of cytokinin signaling inhibitor proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.04.07.536060. [PMID: 37066395 PMCID: PMC10104159 DOI: 10.1101/2023.04.07.536060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
Robustness is the invariant development of phenotype despite environmental changes and genetic perturbations. In the Arabidopsis flower bud, four sepals robustly initiate and grow to constant size to enclose and protect the inner floral organs. We previously characterized the mutant development related myb-like1 ( drmy1 ), where 3-5 sepals initiate variably and grow to different sizes, compromising their protective function. The molecular mechanism underlying this loss of robustness was unclear. Here, we show that drmy1 has reduced TARGET OF RAPAMYCIN (TOR) activity, ribosomal content, and translation. Translation reduction decreases the protein level of ARABIDOPSIS RESPONSE REGULATOR7 (ARR7) and ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN 6 (AHP6), two cytokinin signaling inhibitors that are normally rapidly produced before sepal initiation. The resultant upregulation of cytokinin signaling disrupts robust auxin patterning and sepal initiation. Our work shows that the homeostasis of translation, a ubiquitous cellular process, is crucial for the robust spatiotemporal patterning of organogenesis.
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Wu HYL, Jen J, Hsu PY. What, where, and how: Regulation of translation and the translational landscape in plants. THE PLANT CELL 2024; 36:1540-1564. [PMID: 37437121 PMCID: PMC11062462 DOI: 10.1093/plcell/koad197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/14/2023] [Accepted: 06/15/2023] [Indexed: 07/14/2023]
Abstract
Translation is a crucial step in gene expression and plays a vital role in regulating various aspects of plant development and environmental responses. It is a dynamic and complex program that involves interactions between mRNAs, transfer RNAs, and the ribosome machinery through both cis- and trans-regulation while integrating internal and external signals. Translational control can act in a global (transcriptome-wide) or mRNA-specific manner. Recent advances in genome-wide techniques, particularly ribosome profiling and proteomics, have led to numerous exciting discoveries in both global and mRNA-specific translation. In this review, we aim to provide a "primer" that introduces readers to this fascinating yet complex cellular process and provide a big picture of how essential components connect within the network. We begin with an overview of mRNA translation, followed by a discussion of the experimental approaches and recent findings in the field, focusing on unannotated translation events and translational control through cis-regulatory elements on mRNAs and trans-acting factors, as well as signaling networks through 3 conserved translational regulators TOR, SnRK1, and GCN2. Finally, we briefly touch on the spatial regulation of mRNAs in translational control. Here, we focus on cytosolic mRNAs; translation in organelles and viruses is not covered in this review.
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Affiliation(s)
- Hsin-Yen Larry Wu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Joey Jen
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Polly Yingshan Hsu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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8
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Xiang X, Deng Q, Zheng Y, He Y, Ji D, Vejlupkova Z, Fowler JE, Zhou L. Genome-wide investigation of the LARP gene family: focus on functional identification and transcriptome profiling of ZmLARP6c1 in maize pollen. BMC PLANT BIOLOGY 2024; 24:348. [PMID: 38684961 PMCID: PMC11057080 DOI: 10.1186/s12870-024-05054-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 04/19/2024] [Indexed: 05/02/2024]
Abstract
BACKGROUND The La-related proteins (LARPs) are a superfamily of RNA-binding proteins associated with regulation of gene expression. Evidence points to an important role for post-transcriptional control of gene expression in germinating pollen tubes, which could be aided by RNA-binding proteins. RESULTS In this study, a genome-wide investigation of the LARP proteins in eight plant species was performed. The LARP proteins were classified into three families based on a phylogenetic analysis. The gene structure, conserved motifs, cis-acting elements in the promoter, and gene expression profiles were investigated to provide a comprehensive overview of the evolutionary history and potential functions of ZmLARP genes in maize. Moreover, ZmLARP6c1 was specifically expressed in pollen and ZmLARP6c1 was localized to the nucleus and cytoplasm in maize protoplasts. Overexpression of ZmLARP6c1 enhanced the percentage pollen germination compared with that of wild-type pollen. In addition, transcriptome profiling analysis revealed that differentially expressed genes included PABP homologous genes and genes involved in jasmonic acid and abscisic acid biosynthesis, metabolism, signaling pathways and response in a Zmlarp6c1::Ds mutant and ZmLARP6c1-overexpression line compared with the corresponding wild type. CONCLUSIONS The findings provide a basis for further evolutionary and functional analyses, and provide insight into the critical regulatory function of ZmLARP6c1 in maize pollen germination.
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Affiliation(s)
- Xiaoqin Xiang
- College of Agronomy and Biotechnology, Maize Research Institute, Southwest University, Beibei, Chongqing, 400715, China
| | - Qianxia Deng
- College of Agronomy and Biotechnology, Maize Research Institute, Southwest University, Beibei, Chongqing, 400715, China
| | - Yi Zheng
- College of Agronomy and Biotechnology, Maize Research Institute, Southwest University, Beibei, Chongqing, 400715, China
| | - Yi He
- College of Agronomy and Biotechnology, Maize Research Institute, Southwest University, Beibei, Chongqing, 400715, China
| | - Dongpu Ji
- College of Agronomy and Biotechnology, Maize Research Institute, Southwest University, Beibei, Chongqing, 400715, China
| | - Zuzana Vejlupkova
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA
| | - John E Fowler
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA
| | - Lian Zhou
- College of Agronomy and Biotechnology, Maize Research Institute, Southwest University, Beibei, Chongqing, 400715, China.
- Engineering Research Center of South Upland Agriculture, Ministry of Education, Chongqing, 400715, China.
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9
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Kearly A, Nelson ADL, Skirycz A, Chodasiewicz M. Composition and function of stress granules and P-bodies in plants. Semin Cell Dev Biol 2024; 156:167-175. [PMID: 36464613 DOI: 10.1016/j.semcdb.2022.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/16/2022] [Accepted: 11/22/2022] [Indexed: 12/03/2022]
Abstract
Stress Granules (SGs) and Processing-bodies (P-bodies) are biomolecular condensates formed in the cell with the highly conserved purpose of maintaining balance between storage, translation, and degradation of mRNA. This balance is particularly important when cells are exposed to different environmental conditions and adjustments have to be made in order for plants to respond to and tolerate stressful conditions. While P-bodies are constitutively present in the cell, SG formation is a stress-induced event. Typically thought of as protein-RNA aggregates, SGs and P-bodies are formed by a process called liquid-liquid phase separation (LLPS), and both their function and composition are very dynamic. Both foci are known to contain proteins involved in translation, protein folding, and ATPase activity, alluding to their roles in regulating mRNA and protein expression levels. From an RNA perspective, SGs and P-bodies primarily consist of mRNAs, though long non-coding RNAs (lncRNAs) have also been observed, and more focus is now being placed on the specific RNAs associated with these aggregates. Recently, metabolites such as nucleotides and amino acids have been reported in purified plant SGs with implications for the energetic dynamics of these condensates. Thus, even though the field of plant SGs and P-bodies is relatively nascent, significant progress has been made in understanding their composition and biological role in stress responses. In this review, we discuss the most recent discoveries centered around SG and P-body function and composition in plants.
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Affiliation(s)
- Alyssa Kearly
- The Boyce Thompson Institute, Cornell University, Ithaca, NY, USA
| | | | | | - Monika Chodasiewicz
- Center for Desert Agriculture, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
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Rabeh K, Oubohssaine M, Hnini M. TOR in plants: Multidimensional regulators of plant growth and signaling pathways. JOURNAL OF PLANT PHYSIOLOGY 2024; 294:154186. [PMID: 38330538 DOI: 10.1016/j.jplph.2024.154186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 01/20/2024] [Accepted: 01/22/2024] [Indexed: 02/10/2024]
Abstract
Target Of Rapamycin (TOR) represents a ubiquitous kinase complex that has emerged as a central regulator of cell growth and metabolism in nearly all eukaryotic organisms. TOR is an evolutionarily conserved protein kinase, functioning as a central signaling hub that integrates diverse internal and external cues to regulate a multitude of biological processes. These processes collectively exert significant influence on plant growth, development, nutrient assimilation, photosynthesis, fruit ripening, and interactions with microorganisms. Within the plant domain, the TOR complex comprises three integral components: TOR, RAPTOR, and LST8. This comprehensive review provides insights into various facets of the TOR protein, encompassing its origin, structure, function, and the regulatory and signaling pathways operative in photosynthetic organisms. Additionally, we explore future perspectives related to this pivotal protein kinase.
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Affiliation(s)
- Karim Rabeh
- Microbiology and Molecular Biology Team, Center of Plant and Microbial Biotechnologies, Biodiversity and Environment, Faculty of Sciences, Mohammed V University, Rabat, Morocco.
| | - Malika Oubohssaine
- Microbiology and Molecular Biology Team, Center of Plant and Microbial Biotechnologies, Biodiversity and Environment, Faculty of Sciences, Mohammed V University, Rabat, Morocco
| | - Mohamed Hnini
- Microbiology and Molecular Biology Team, Center of Plant and Microbial Biotechnologies, Biodiversity and Environment, Faculty of Sciences, Mohammed V University, Rabat, Morocco
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11
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Calderan-Rodrigues MJ, Caldana C. Impact of the TOR pathway on plant growth via cell wall remodeling. JOURNAL OF PLANT PHYSIOLOGY 2024; 294:154202. [PMID: 38422631 DOI: 10.1016/j.jplph.2024.154202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 03/02/2024]
Abstract
Plant growth is intimately linked to the availability of carbon and energy status. The Target of rapamycin (TOR) pathway is a highly relevant metabolic sensor and integrator of plant-assimilated C into development and growth. The cell wall accounts for around a third of the cell biomass, and the investment of C into this structure should be finely tuned for optimal growth. The plant C status plays a significant role in controlling the rate of cell wall synthesis. TOR signaling regulates cell growth and expansion, which are fundamental processes for plant development. The availability of nutrients and energy, sensed and integrated by TOR, influences cell division and elongation, ultimately impacting the synthesis and deposition of cell wall components. The plant cell wall is crucial in environmental adaptation and stress responses. TOR senses and internalizes various environmental cues, such as nutrient availability and stresses. These environmental factors influence TOR activity, which modulates cell wall remodeling to cope with changing conditions. Plant hormones, including auxins, gibberellins, and brassinosteroids, also regulate TOR signaling and cell wall-related processes. The connection between nutrients and cell wall pathways modulated by TOR are discussed.
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Affiliation(s)
- Maria Juliana Calderan-Rodrigues
- Max-Planck Institut für Molekulare Pflanzenphysiologie, 14476, Potsdam-Golm, Germany; Universidade de São Paulo, Escola Superior de Agricultura "Luiz de Queiroz", 13418-900, Piracicaba, SP, Brazil.
| | - Camila Caldana
- Max-Planck Institut für Molekulare Pflanzenphysiologie, 14476, Potsdam-Golm, Germany
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12
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Canal MV, Mansilla N, Gras DE, Ibarra A, Figueroa CM, Gonzalez DH, Welchen E. Cytochrome c levels affect the TOR pathway to regulate growth and metabolism under energy-deficient conditions. THE NEW PHYTOLOGIST 2024; 241:2039-2058. [PMID: 38191763 DOI: 10.1111/nph.19506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/03/2023] [Indexed: 01/10/2024]
Abstract
Mitochondrial function is essential for plant growth, but the mechanisms involved in adjusting growth and metabolism to changes in mitochondrial energy production are not fully understood. We studied plants with reduced expression of CYTC-1, one of two genes encoding the respiratory chain component cytochrome c (CYTc) in Arabidopsis, to understand how mitochondria communicate their status to coordinate metabolism and growth. Plants with CYTc deficiency show decreased mitochondrial membrane potential and lower ATP content, even when carbon sources are present. They also exhibit higher free amino acid content, induced autophagy, and increased resistance to nutritional stress caused by prolonged darkness, similar to plants with triggered starvation signals. CYTc deficiency affects target of rapamycin (TOR)-pathway activation, reducing S6 kinase (S6K) and RPS6A phosphorylation, as well as total S6K protein levels due to increased protein degradation via proteasome and autophagy. TOR overexpression restores growth and other parameters affected in cytc-1 mutants, even if mitochondrial membrane potential and ATP levels remain low. We propose that CYTc-deficient plants coordinate their metabolism and energy availability by reducing TOR-pathway activation as a preventive signal to adjust growth in anticipation of energy exhaustion, thus providing a mechanism by which changes in mitochondrial activity are transduced to the rest of the cell.
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Affiliation(s)
- María Victoria Canal
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
| | - Natanael Mansilla
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
| | - Diana E Gras
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
| | - Agustín Ibarra
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
| | - Carlos M Figueroa
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
| | - Daniel H Gonzalez
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
| | - Elina Welchen
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
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13
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Hochstoeger T, Chao JA. Towards a molecular understanding of the 5'TOP motif in regulating translation of ribosomal mRNAs. Semin Cell Dev Biol 2024; 154:99-104. [PMID: 37316417 DOI: 10.1016/j.semcdb.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 04/14/2023] [Accepted: 06/05/2023] [Indexed: 06/16/2023]
Abstract
Vertebrate cells have evolved a simple, yet elegant, mechanism for coordinated regulation of ribosome biogenesis mediated by the 5' terminal oligopyrimidine motif (5'TOP). This motif allows cells to rapidly adapt to changes in the environment by specifically modulating translation rate of mRNAs encoding the translation machinery. Here, we provide an overview of the origin of this motif, its characterization, and progress in identifying the key regulatory factors involved. We highlight challenges in the field of 5'TOP research, and discuss future approaches that we think will be able to resolve outstanding questions.
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Affiliation(s)
- Tobias Hochstoeger
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; University of Basel, 4003 Basel, Switzerland
| | - Jeffrey A Chao
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland.
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14
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Li W, Liu J, Li Z, Ye R, Chen W, Huang Y, Yuan Y, Zhang Y, Hu H, Zheng P, Fang Z, Tao Z, Song S, Pan R, Zhang J, Tu J, Sheen J, Du H. Mitigating growth-stress tradeoffs via elevated TOR signaling in rice. MOLECULAR PLANT 2024; 17:240-257. [PMID: 38053337 PMCID: PMC11271712 DOI: 10.1016/j.molp.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/29/2023] [Accepted: 12/01/2023] [Indexed: 12/07/2023]
Abstract
Rice production accounts for approximately half of the freshwater resources utilized in agriculture, resulting in greenhouse gas emissions such as methane (CH4) from flooded paddy fields. To address this challenge, environmentally friendly and cost-effective water-saving techniques have become widely adopted in rice cultivation. However, the implementation of water-saving treatments (WSTs) in paddy-field rice has been associated with a substantial yield loss of up to 50% as well as a reduction in nitrogen use efficiency (NUE). In this study, we discovered that the target of rapamycin (TOR) signaling pathway is compromised in rice under WST. Polysome profiling-coupled transcriptome sequencing (polysome-seq) analysis unveiled a substantial reduction in global translation in response to WST associated with the downregulation of TOR activity. Molecular, biochemical, and genetic analyses revealed new insights into the impact of the positive TOR-S6K-RPS6 and negative TOR-MAF1 modules on translation repression under WST. Intriguingly, ammonium exhibited a greater ability to alleviate growth constraints under WST by enhancing TOR signaling, which simultaneously promoted uptake and utilization of ammonium and nitrogen allocation. We further demonstrated that TOR modulates the ammonium transporter AMT1;1 as well as the amino acid permease APP1 and dipeptide transporter NPF7.3 at the translational level through the 5' untranslated region. Collectively, these findings reveal that enhancing TOR signaling could mitigate rice yield penalty due to WST by regulating the processes involved in protein synthesis and NUE. Our study will contribute to the breeding of new rice varieties with increased water and fertilizer utilization efficiency.
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Affiliation(s)
- Wei Li
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China; ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311215, China
| | - Jiaqi Liu
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China
| | - Zeqi Li
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China; Hainan Institute of Zhejiang University, Sanya 572025, China
| | - Ruiqiang Ye
- National Key Laboratory of Plant Molecular Genetics, CAS, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Wenzhen Chen
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China; Hainan Institute of Zhejiang University, Sanya 572025, China
| | - Yuqing Huang
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China
| | - Yue Yuan
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China
| | - Yi Zhang
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China
| | - Huayi Hu
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China
| | - Peng Zheng
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China; ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311215, China
| | - Zhongming Fang
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Agricultural Sciences, Guizhou University, Guiyang 550025, China
| | - Zeng Tao
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China
| | - Shiyong Song
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China
| | - Ronghui Pan
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China; ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311215, China
| | - Jian Zhang
- State Key Laboratory of Rice Biology and Breeding, China National Rice Research Institute, Hangzhou 311400, China
| | - Jumim Tu
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China
| | - Jen Sheen
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Hao Du
- State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Yu-Hang-Tang Road No. 866, Hangzhou 310058, China; ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311215, China; Hainan Institute of Zhejiang University, Sanya 572025, China.
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15
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Careno DA, Assaf CH, Eggermont EDC, Canelo M, Cerdán PD, Yanovsky MJ. Role of Phytochromes in Red Light-Regulated Alternative Splicing in Arabidopsis thaliana: Impactful but Not Indispensable. Cells 2023; 12:2447. [PMID: 37887291 PMCID: PMC10605401 DOI: 10.3390/cells12202447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/04/2023] [Accepted: 10/10/2023] [Indexed: 10/28/2023] Open
Abstract
Light is both the main source of energy and a key environmental signal for plants. It regulates not only gene expression but also the tightly related processes of splicing and alternative splicing (AS). Two main pathways have been proposed to link light sensing with the splicing machinery. One occurs through a photosynthesis-related signal, and the other is mediated by photosensory proteins, such as red light-sensing phytochromes. Here, we evaluated the relative contribution of each of these pathways by performing a transcriptome-wide analysis of light regulation of AS in plants that do not express any functional phytochrome (phyQ). We found that an acute 2-h red-light pulse in the middle of the night induces changes in the splicing patterns of 483 genes in wild-type plants. Approximately 30% of these genes also showed strong light regulation of splicing patterns in phyQ mutant plants, revealing that phytochromes are important but not essential for the regulation of AS by R light. We then performed a meta-analysis of related transcriptomic datasets and found that different light regulatory pathways can have overlapping targets in terms of AS regulation. All the evidence suggests that AS is regulated simultaneously by various light signaling pathways, and the relative contribution of each pathway is highly dependent on the plant developmental stage.
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Affiliation(s)
- Daniel Alejandro Careno
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires–Consejo Nacional de Investigaciones Científicas y Técnicas (IIBBA-CONICET), Buenos Aires C1405BWE, Argentina; (C.H.A.); (E.D.C.E.); (M.C.); (P.D.C.)
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
| | - Constanza Helena Assaf
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires–Consejo Nacional de Investigaciones Científicas y Técnicas (IIBBA-CONICET), Buenos Aires C1405BWE, Argentina; (C.H.A.); (E.D.C.E.); (M.C.); (P.D.C.)
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
| | - Eline Dieuwerke Catharina Eggermont
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires–Consejo Nacional de Investigaciones Científicas y Técnicas (IIBBA-CONICET), Buenos Aires C1405BWE, Argentina; (C.H.A.); (E.D.C.E.); (M.C.); (P.D.C.)
- Plant-Environment Signaling Group, Department of Biology, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Micaela Canelo
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires–Consejo Nacional de Investigaciones Científicas y Técnicas (IIBBA-CONICET), Buenos Aires C1405BWE, Argentina; (C.H.A.); (E.D.C.E.); (M.C.); (P.D.C.)
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
| | - Pablo Diego Cerdán
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires–Consejo Nacional de Investigaciones Científicas y Técnicas (IIBBA-CONICET), Buenos Aires C1405BWE, Argentina; (C.H.A.); (E.D.C.E.); (M.C.); (P.D.C.)
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
| | - Marcelo Javier Yanovsky
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires–Consejo Nacional de Investigaciones Científicas y Técnicas (IIBBA-CONICET), Buenos Aires C1405BWE, Argentina; (C.H.A.); (E.D.C.E.); (M.C.); (P.D.C.)
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16
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Zhang Z, Zhong Z, Xiong Y. Sailing in complex nutrient signaling networks: Where I am, where to go, and how to go? MOLECULAR PLANT 2023; 16:1635-1660. [PMID: 37740490 DOI: 10.1016/j.molp.2023.09.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/24/2023]
Abstract
To ensure survival and promote growth, sessile plants have developed intricate internal signaling networks tailored in diverse cells and organs with both shared and specialized functions that respond to various internal and external cues. A fascinating question arises: how can a plant cell or organ diagnose the spatial and temporal information it is experiencing to know "where I am," and then is able to make the accurate specific responses to decide "where to go" and "how to go," despite the absence of neuronal systems found in mammals. Drawing inspiration from recent comprehensive investigations into diverse nutrient signaling pathways in plants, this review focuses on the interactive nutrient signaling networks mediated by various nutrient sensors and transducers. We assess and illustrate examples of how cells and organs exhibit specific responses to changing spatial and temporal information within these interactive plant nutrient networks. In addition, we elucidate the underlying mechanisms by which plants employ posttranslational modification codes to integrate different upstream nutrient signals, thereby conferring response specificities to the signaling hub proteins. Furthermore, we discuss recent breakthrough studies that demonstrate the potential of modulating nutrient sensing and signaling as promising strategies to enhance crop yield, even with reduced fertilizer application.
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Affiliation(s)
- Zhenzhen Zhang
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Haixia Institute of Science and Technology, Synthetic Biology Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zhaochen Zhong
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Haixia Institute of Science and Technology, Synthetic Biology Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yan Xiong
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Haixia Institute of Science and Technology, Synthetic Biology Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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17
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Saile J, Wießner-Kroh T, Erbstein K, Obermüller DM, Pfeiffer A, Janocha D, Lohmann J, Wachter A. SNF1-RELATED KINASE 1 and TARGET OF RAPAMYCIN control light-responsive splicing events and developmental characteristics in etiolated Arabidopsis seedlings. THE PLANT CELL 2023; 35:3413-3428. [PMID: 37338062 PMCID: PMC10473197 DOI: 10.1093/plcell/koad168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 05/23/2023] [Accepted: 06/12/2023] [Indexed: 06/21/2023]
Abstract
The kinases SNF1-RELATED KINASE 1 (SnRK1) and TARGET OF RAPAMYCIN (TOR) are central sensors of the energy status, linking this information via diverse regulatory mechanisms to plant development and stress responses. Despite the well-studied functions of SnRK1 and TOR under conditions of limited or ample energy availability, respectively, little is known about the extent to which the 2 sensor systems function and how they are integrated in the same molecular process or physiological context. Here, we demonstrate that both SnRK1 and TOR are required for proper skotomorphogenesis in etiolated Arabidopsis (Arabidopsis thaliana) seedlings, light-induced cotyledon opening, and regular development in light. Furthermore, we identify SnRK1 and TOR as signaling components acting upstream of light- and sugar-regulated alternative splicing events, expanding the known action spectra for these 2 key players in energy signaling. Our findings imply that concurring SnRK1 and TOR activities are required throughout various phases of plant development. Based on the current knowledge and our findings, we hypothesize that turning points in the activities of these sensor kinases, as expected to occur upon illumination of etiolated seedlings, instead of signaling thresholds reflecting the nutritional status may modulate developmental programs in response to altered energy availability.
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Affiliation(s)
- Jennifer Saile
- Institute for Molecular Physiology (imP), University of Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany
| | - Theresa Wießner-Kroh
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany
| | - Katarina Erbstein
- Institute for Molecular Physiology (imP), University of Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
| | - Dominik M Obermüller
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany
| | - Anne Pfeiffer
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Denis Janocha
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Jan Lohmann
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Andreas Wachter
- Institute for Molecular Physiology (imP), University of Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany
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18
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Dong Y, Srour O, Lukhovitskaya N, Makarian J, Baumberger N, Galzitskaya O, Elser D, Schepetilnikov M, Ryabova LA. Functional analogs of mammalian 4E-BPs reveal a role for TOR in global plant translation. Cell Rep 2023; 42:112892. [PMID: 37516965 DOI: 10.1016/j.celrep.2023.112892] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 05/22/2023] [Accepted: 07/13/2023] [Indexed: 08/01/2023] Open
Abstract
Mammalian/mechanistic target of rapamycin (mTOR) regulates global protein synthesis through inactivation of eIF4E-binding proteins (m4E-BPs) in response to nutrient and energy availability. Until now, 4E-BPs have been considered as metazoan inventions, and how target of rapamycin (TOR) controls cap-dependent translation initiation in plants remains obscure. Here, we present short unstructured 4E-BP-like Arabidopsis proteins (4EBP1/4EBP2) that are non-homologous to m4E-BPs except for the eIF4E-binding motif and TOR phosphorylation sites. Unphosphorylated 4EBPs exhibit strong affinity toward eIF4Es and can inhibit formation of the cap-binding complex. Upon TOR activation, 4EBPs are phosphorylated, probably when bound directly to TOR, and likely relocated to ribosomes. 4EBPs can suppress a distinct set of mRNAs; 4EBP2 predominantly inhibits translation of core cell-cycle regulators CycB1;1 and CycD1;1, whereas 4EBP1 interferes with chlorophyll biosynthesis. Accordingly, 4EBP2 overexpression halts early seedling development, which is overcome by induction of Glc/Suc-TOR signaling. Thus, TOR regulates cap-dependent translation initiation by inactivating atypical 4EBPs in plants.
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Affiliation(s)
- Yihan Dong
- Institut de biologie moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Ola Srour
- Institut de biologie moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Nina Lukhovitskaya
- Institut de biologie moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Joelle Makarian
- Institut de biologie moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Nicolas Baumberger
- Institut de biologie moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Oxana Galzitskaya
- Institute of Protein Research of the Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia
| | - David Elser
- Institut de biologie moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Mikhail Schepetilnikov
- Institut de biologie moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France.
| | - Lyubov A Ryabova
- Institut de biologie moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France.
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19
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Buckley CR, Li X, Martí MC, Haydon MJ. A bittersweet symphony: Metabolic signals in the circadian system. CURRENT OPINION IN PLANT BIOLOGY 2023; 73:102333. [PMID: 36640635 DOI: 10.1016/j.pbi.2022.102333] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/03/2022] [Accepted: 12/08/2022] [Indexed: 06/10/2023]
Abstract
Plants must match their metabolism to daily and seasonal fluctuations in their environment to maximise performance in natural conditions. Circadian clocks enable organisms to anticipate and adapt to these predictable and unpredictable environmental challenges. Metabolism is increasingly recognised as an integrated feature of the plant circadian system. Metabolism is an important circadian-regulated output but also provides input to this dynamic timekeeping mechanism. The spatial organisation of metabolism within cells and between tissues, and the temporal features of metabolism across days, seasons and development, raise interesting questions about how metabolism influences circadian timekeeping. The various mechanisms by which metabolic signals influence the transcription-translation feedback loops of the circadian oscillator are emerging. These include roles for major metabolic signalling pathways, various retrograde signals, and direct metabolic modifications of clock genes or proteins. Such metabolic feedback loops enable intra- and intercellular coordination of rhythmic metabolism, and recent discoveries indicate these contribute to diverse aspects of daily, developmental and seasonal timekeeping.
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Affiliation(s)
| | - Xiang Li
- School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - María Carmen Martí
- Department of Stress Biology and Plant Pathology, Centre of Edaphology and Applied Biology of Segura (CEBAS-CSIC), 30110 Murcia, Spain
| | - Michael J Haydon
- School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia.
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20
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Wang B, Yang R, Zhang Z, Huang S, Ji Z, Zheng W, Zhang H, Zhang Y, Feng F. Integration of miRNA and mRNA analysis reveals the role of ribosome in to anti-artificial aging in sweetcorn. Int J Biol Macromol 2023; 240:124434. [PMID: 37062384 DOI: 10.1016/j.ijbiomac.2023.124434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 03/03/2023] [Accepted: 03/31/2023] [Indexed: 04/18/2023]
Abstract
Sweetcorn is a kind of maize with high sugar content and has poor seed aging tolerance, which seriously limits its production. However, few studies have explored the artificial aging (AA) tolerance by miRNA-mRNA integration analysis in sweetcorn. Here, we characterized the physiological, biochemical and transcriptomic changes of two contrasting lines K62 and K107 treated with AA during time series. Both the germination indexes and antioxidant enzymes showed significant difference between two lines. The MDA content of AA-tolerant genotype K62 was significantly lower than that of K107 on the fourth and sixth day. Subsequently, 157 differentially expressed miRNAs (DEMIs) and 8878 differentially expressed mRNAs (DEMs) were identified by RNA-seq analysis under aging stress. The "ribosome" and "peroxisome" pathways were enriched to respond to aging stress, genes for both large units and small ribosomal subunits were significantly upregulated expressed and higher translation efficiency might exist in K62. Thirteen pairs of miRNA-target genes were obtained, and 8 miRNA-mRNA pairs might involve in ribosome protein and translation process. Our results elucidate the mechanism of sweetcorn response to AA at miRNA-mRNA level, and provide a new insight into sweetcorn AA response to stress.
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Affiliation(s)
- Bo Wang
- The Key Laboratory of Plant Molecular Breeding of Guangdong Province, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China
| | - Ruichun Yang
- The Key Laboratory of Plant Molecular Breeding of Guangdong Province, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China
| | - Zili Zhang
- Guangzhou Key Laboratory for Research and Development of Crop Germplasm Resources, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Silin Huang
- The Key Laboratory of Plant Molecular Breeding of Guangdong Province, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China
| | - Zhaoqian Ji
- The Key Laboratory of Plant Molecular Breeding of Guangdong Province, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China
| | - Wenbo Zheng
- The Key Laboratory of Plant Molecular Breeding of Guangdong Province, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China
| | - Huaxing Zhang
- The Key Laboratory of Plant Molecular Breeding of Guangdong Province, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China
| | - Yafeng Zhang
- The Key Laboratory of Plant Molecular Breeding of Guangdong Province, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China
| | - Faqiang Feng
- The Key Laboratory of Plant Molecular Breeding of Guangdong Province, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China.
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21
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Ingargiola C, Jéhanno I, Forzani C, Marmagne A, Broutin J, Clément G, Leprince AS, Meyer C. The Arabidopsis Target of Rapamycin (TOR) kinase regulates ammonium assimilation and glutamine metabolism. PLANT PHYSIOLOGY 2023:kiad216. [PMID: 37042394 DOI: 10.1093/plphys/kiad216] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 03/01/2023] [Accepted: 04/11/2023] [Indexed: 06/19/2023]
Abstract
In eukaryotes, Target of Rapamycin (TOR) is a well conserved kinase that controls cell metabolism and growth in response to nutrients and environmental factors. Nitrogen (N) is an essential element for plants, and TOR functions as a crucial N and amino acid sensor in animals and yeast. However, knowledge on the connections between TOR and the overall N metabolism and assimilation in plants is still limited. In this study, we investigated the regulation of TOR in Arabidopsis (Arabidopsis thaliana) by the N source as well as the impact of TOR deficiency on N metabolism. Inhibition of TOR globally decreased ammonium uptake while triggering a massive accumulation of amino acids, such as Gln, but also of polyamines. Consistently, TOR complex mutants were hypersensitive to Gln. We also showed that the glutamine synthetase inhibitor glufosinate abolishes Gln accumulation resulting from TOR inhibition and improves the growth of TOR complex mutants. These results suggest that a high level of Gln contributes to the reduction in plant growth resulting from TOR inhibition. Glutamine synthetase activity was reduced by TOR inhibition while the enzyme amount increased. In conclusion, our findings show that the TOR pathway is intimately connected to N metabolism and that a decrease in TOR activity results in glutamine synthetase-dependent Gln and amino acid accumulation.
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Affiliation(s)
- Camille Ingargiola
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Isabelle Jéhanno
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Céline Forzani
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Anne Marmagne
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Justine Broutin
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Gilles Clément
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Anne-Sophie Leprince
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
- Faculté des Sciences et d'Ingénierie, Sorbonne Université, UFR 927, 4 Place Jussieu, 75252 Paris, France
| | - Christian Meyer
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
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22
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Ma X, Jia Q, Li S, Chen Z, Ming X, Zhao Y, Zhou DX. An enhanced network of energy metabolism, lysine acetylation, and growth-promoting protein accumulation is associated with heterosis in elite hybrid rice. PLANT COMMUNICATIONS 2023:100560. [PMID: 36774536 PMCID: PMC10363507 DOI: 10.1016/j.xplc.2023.100560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/08/2022] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
Heterosis refers to the superior performance of a hybrid compared with its parental lines. Although several genetic and molecular models have been proposed to explain heterosis, it remains unclear how hybrid cells integrate complementary gene expression or activity to drive heterotic growth. In this work, we show that accumulation of growth-promoting and energy metabolism proteins, enhanced energy metabolism activities, and increased protein lysine acetylation were associated with superior growth of the panicle meristem in the elite hybrid rice Shanyou 63 relative to its parental varieties. Metabolism of nuclear/cytosolic acetyl-coenzyme A was also enhanced in the hybrid, which paralleled increases in histone H3 acetylation to selectively target the expression of growth-promoting and metabolic genes. Lysine acetylation of cellular proteins, including TARGET OF RAPAMYCIN complex 1, ribosomal proteins, and energy metabolism enzymes, was also augmented and/or remodeled to modulate their activities. The data indicate that an enhanced network of energy-producing metabolic activity and growth-promoting histone acetylation/gene expression in the hybrid could contribute to its superior growth rate and may constitute a model to explain heterosis.
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Affiliation(s)
- Xuan Ma
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Qingxiao Jia
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Sheng Li
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhengting Chen
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Xin Ming
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Yu Zhao
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Dao-Xiu Zhou
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China; Institute of Plant Science Paris-Saclay (IPS2), CNRS, INRAE, University Paris-Saclay, 91405 Orsay, France.
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23
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Chen X, Kim SH, Rhee S, Witte CP. A plastid nucleoside kinase is involved in inosine salvage and control of purine nucleotide biosynthesis. THE PLANT CELL 2023; 35:510-528. [PMID: 36342213 PMCID: PMC9806653 DOI: 10.1093/plcell/koac320] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 11/02/2022] [Indexed: 05/19/2023]
Abstract
In nucleotide metabolism, nucleoside kinases recycle nucleosides into nucleotides-a process called nucleoside salvage. Nucleoside kinases for adenosine, uridine, and cytidine have been characterized from many organisms, but kinases for inosine and guanosine salvage are not yet known in eukaryotes and only a few such enzymes have been described from bacteria. Here we identified Arabidopsis thaliana PLASTID NUCLEOSIDE KINASE 1 (PNK1), an enzyme highly conserved in plants and green algae belonging to the Phosphofructokinase B family. We demonstrate that PNK1 from A. thaliana is located in plastids and catalyzes the phosphorylation of inosine, 5-aminoimidazole-4-carboxamide-1-β-d-ribose (AICA ribonucleoside), and uridine but not guanosine in vitro, and is involved in inosine salvage in vivo. PNK1 mutation leads to increased flux into purine nucleotide catabolism and, especially in the context of defective uridine degradation, to over-accumulation of uridine and UTP as well as growth depression. The data suggest that PNK1 is involved in feedback regulation of purine nucleotide biosynthesis and possibly also pyrimidine nucleotide biosynthesis. We additionally report that cold stress leads to accumulation of purine nucleotides, probably by inducing nucleotide biosynthesis, but that this adjustment of nucleotide homeostasis to environmental conditions is not controlled by PNK1.
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Affiliation(s)
- Xiaoguang Chen
- Department of Molecular Nutrition and Biochemistry of Plants, Leibniz Universität Hannover, Hannover 30419, Germany
| | - Sang-Hoon Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Republic of Korea
| | - Sangkee Rhee
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Republic of Korea
| | - Claus-Peter Witte
- Department of Molecular Nutrition and Biochemistry of Plants, Leibniz Universität Hannover, Hannover 30419, Germany
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24
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Bakshi A, Moin M, Gayatri MB, Reddy ABM, Datla R, Madhav MS, Kirti PB. Involvement of Target of Rapamycin (TOR) Signaling in the Regulation of Crosstalk between Ribosomal Protein Small Subunit 6 Kinase-1 (RPS6K-1) and Ribosomal Proteins. PLANTS (BASEL, SWITZERLAND) 2023; 12:176. [PMID: 36616305 PMCID: PMC9824793 DOI: 10.3390/plants12010176] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
The target of rapamycin (TOR) protein phosphorylates its downstream effector p70kDa ribosomal protein S6 kinases (S6K1) for ribosome biogenesis and translation initiation in eukaryotes. However, the molecular mechanism of TOR-S6K1-ribosomal protein (RP) signaling is not well understood in plants. In the present study, we report the transcriptional upregulation of ribosomal protein large and small subunit (RPL and RPS) genes in the previously established TOR overexpressing transgenic lines of rice (in Oryza sativa ssp. indica, variety BPT-5204, TR-2.24 and TR-15.1) and of Arabidopsis thaliana (in Col 0 ecotype, ATR-1.4.27 and ATR-3.7.32). The mRNA levels of RP genes from this study were compared with those previously available in transcriptomic datasets on the expression of RPs in relation to TOR inhibitor and in the TOR-RNAi lines of Arabidopsis thaliana. We further analyzed TOR activity, i.e., S6K1 phosphorylation in SALK lines of Arabidopsis with mutation in rpl6, rpl18, rpl23, rpl24 and rps28C, where the rpl18 mutant showed inactivation of S6K1 phosphorylation. We also predicted similar putative Ser/Thr phosphorylation sites for ribosomal S6 kinases (RSKs) in the RPs of Oryza sativa ssp. indica and Arabidopsis thaliana. The findings of this study indicate that the TOR pathway is possibly interlinked in a cyclic manner via the phosphorylation of S6K1 as a modulatory step for the regulation of RP function to switch 'on'/'off' the translational regulation for balanced plant growth.
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Affiliation(s)
- Achala Bakshi
- Indian Institute of Rice Research, Rajendranagar, Hyderabad 500030, Telangana, India
- Global Institute for Food Security, Saskatoon, SK S7N 0W9, Canada
| | - Mazahar Moin
- Indian Institute of Rice Research, Rajendranagar, Hyderabad 500030, Telangana, India
- Agri Biotech Foundation, PJTS Agricultural University Campus, Rajendranagar, Hyderabad 500030, Telangana, India
| | - Meher B. Gayatri
- Department of Animal Biology, University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Aramati B. M. Reddy
- Department of Animal Biology, University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Raju Datla
- Global Institute for Food Security, Saskatoon, SK S7N 0W9, Canada
| | - Maganti S. Madhav
- Indian Institute of Rice Research, Rajendranagar, Hyderabad 500030, Telangana, India
- Central Tobacco Research Institute, Rajahmundry 533105, Andhra Pradesh, India
| | - Pulugurtha B. Kirti
- Agri Biotech Foundation, PJTS Agricultural University Campus, Rajendranagar, Hyderabad 500030, Telangana, India
- Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, Telangana, India
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25
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Busche M, Hake S, Brunkard JO. Terminal ear 1 and phytochromes B1/B2 regulate maize leaf initiation independently. Genetics 2022; 223:6887217. [PMID: 36495288 PMCID: PMC9910401 DOI: 10.1093/genetics/iyac182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/29/2022] [Accepted: 12/01/2022] [Indexed: 12/14/2022] Open
Abstract
Higher plants generate new leaves from shoot meristems throughout their vegetative lifespan. The tempo of leaf initiation is dynamically regulated by physiological cues, but little is known about the underlying genetic signaling pathways that coordinate this rate. Two maize (Zea mays) mutants, terminal ear1 (te1) and phytochrome B1;phytochrome B2 (phyB1;phyB2), oppositely affect leaf initiation rates and total leaf number at the flowering time: te1 mutants make leaves faster whereas phyB1;phyB2 mutants make leaves slower than wild-type plants. To test whether PhyB1, PhyB2, and TE1 act in overlapping or distinct pathways to regulate leaf initiation, we crossed te1 and phyB1;phyB2 created an F2 population segregating for these three mutations and quantified various phenotypes among the resulting genotypes, including leaf number, leaf initiation rate, plant height, leaf length, leaf width, number of juvenile leaves, stalk diameter, and dry shoot biomass. Leaf number and initiation rate in phyB1;phyB2;te1 plants fell between the extremes of the two parents, suggesting an additive genetic interaction between te1 and phyB1;phyB2 rather than epistasis. Therefore, we conclude that PhyB1, PhyB2, and TE1 likely control leaf initiation through distinct signaling pathways.
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Affiliation(s)
- Michael Busche
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Sarah Hake
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA,Plant Gene Expression Center, USDA Agricultural Research Service, Albany, CA 94710, USA
| | - Jacob O Brunkard
- Corresponding author: Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53715, USA.
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26
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Kendrick R, Chotewutmontri P, Belcher S, Barkan A. Correlated retrograde and developmental regulons implicate multiple retrograde signals as coordinators of chloroplast development in maize. THE PLANT CELL 2022; 34:4897-4919. [PMID: 36073948 PMCID: PMC9709983 DOI: 10.1093/plcell/koac276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 09/02/2022] [Indexed: 05/09/2023]
Abstract
Signals emanating from chloroplasts influence nuclear gene expression, but roles of retrograde signals during chloroplast development are unclear. To address this gap, we analyzed transcriptomes of non-photosynthetic maize mutants and compared them to transcriptomes of stages of normal leaf development. The transcriptomes of two albino mutants lacking plastid ribosomes resembled transcriptomes at very early stages of normal leaf development, whereas the transcriptomes of two chlorotic mutants with thylakoid targeting or plastid transcription defects resembled those at a slightly later stage. We identified ∼2,700 differentially expressed genes, which fall into six major categories based on the polarity and mutant-specificity of the change. Downregulated genes were generally expressed late in normal development and were enriched in photosynthesis genes, whereas upregulated genes act early and were enriched for functions in chloroplast biogenesis and cytosolic translation. We showed further that target-of-rapamycin (TOR) signaling was elevated in mutants lacking plastid ribosomes and declined in concert with plastid ribosome buildup during normal leaf development. Our results implicate three plastid signals as coordinators of photosynthetic differentiation. One signal requires plastid ribosomes and activates photosynthesis genes. A second signal reflects attainment of chloroplast maturity and represses chloroplast biogenesis genes. A third signal, the consumption of nutrients by developing chloroplasts, represses TOR, promoting termination of cell proliferation during leaf development.
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Affiliation(s)
- Rennie Kendrick
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403, USA
| | | | - Susan Belcher
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403, USA
| | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403, USA
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27
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van den Elzen AMG, Watson MJ, Thoreen CC. mRNA 5' terminal sequences drive 200-fold differences in expression through effects on synthesis, translation and decay. PLoS Genet 2022; 18:e1010532. [PMID: 36441824 PMCID: PMC9731452 DOI: 10.1371/journal.pgen.1010532] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/08/2022] [Accepted: 11/15/2022] [Indexed: 11/30/2022] Open
Abstract
mRNA regulatory sequences control gene expression at multiple levels including translation initiation and mRNA decay. The 5' terminal sequences of mRNAs have unique regulatory potential because of their proximity to key post-transcriptional regulators. Here we have systematically probed the function of 5' terminal sequences in gene expression in human cells. Using a library of reporter mRNAs initiating with all possible 7-mer sequences at their 5' ends, we find an unexpected impact on transcription that underlies 200-fold differences in mRNA expression. Library sequences that promote high levels of transcription mirrored those found in native mRNAs and define two basic classes with similarities to classic Initiator (Inr) and TCT core promoter motifs. By comparing transcription, translation and decay rates, we identify sequences that are optimized for both efficient transcription and growth-regulated translation and stability, including variants of terminal oligopyrimidine (TOP) motifs. We further show that 5' sequences of endogenous mRNAs are enriched for multi-functional TCT/TOP hybrid sequences. Together, our results reveal how 5' sequences define two general classes of mRNAs with distinct growth-responsive profiles of expression across synthesis, translation and decay.
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Affiliation(s)
- Antonia M. G. van den Elzen
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Maegan J. Watson
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Carson C. Thoreen
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, United States of America
- * E-mail:
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28
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Jamsheer K M, Awasthi P, Laxmi A. The social network of target of rapamycin complex 1 in plants. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:7026-7040. [PMID: 35781571 DOI: 10.1093/jxb/erac278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Target of rapamycin complex 1 (TORC1) is a highly conserved serine-threonine protein kinase crucial for coordinating growth according to nutrient availability in eukaryotes. It works as a central integrator of multiple nutrient inputs such as sugar, nitrogen, and phosphate and promotes growth and biomass accumulation in response to nutrient sufficiency. Studies, especially in the past decade, have identified the central role of TORC1 in regulating growth through interaction with hormones, photoreceptors, and stress signaling machinery in plants. In this review, we comprehensively analyse the interactome and phosphoproteome of the Arabidopsis TORC1 signaling network. Our analysis highlights the role of TORC1 as a central hub kinase communicating with the transcriptional and translational apparatus, ribosomes, chaperones, protein kinases, metabolic enzymes, and autophagy and stress response machinery to orchestrate growth in response to nutrient signals. This analysis also suggests that along with the conserved downstream components shared with other eukaryotic lineages, plant TORC1 signaling underwent several evolutionary innovations and co-opted many lineage-specific components during. Based on the protein-protein interaction and phosphoproteome data, we also discuss several uncharacterized and unexplored components of the TORC1 signaling network, highlighting potential links for future studies.
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Affiliation(s)
- Muhammed Jamsheer K
- Amity Institute of Genome Engineering, Amity University Uttar Pradesh, Noida 201313, India
| | - Prakhar Awasthi
- 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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29
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Urrea-Castellanos R, Caldana C, Henriques R. Growing at the right time: interconnecting the TOR pathway with photoperiod and circadian regulation. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:7006-7015. [PMID: 35738873 PMCID: PMC9664226 DOI: 10.1093/jxb/erac279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
Plants can adjust their growth to specific times of the day and season. Different photoperiods result in distinct growth patterns, which correlate with specific carbon-partitioning strategies in source (leaves) and sink (roots) organs. Therefore, external cues such as light, day length, and temperature need to be integrated with intracellular processes controlling overall carbon availability and anabolism. The target of rapamycin (TOR) pathway is a signalling hub where environmental signals, circadian information, and metabolic processes converge to regulate plant growth. TOR complex mutants display altered patterns of root growth and starch levels. Moreover, depletion of TOR or reduction in cellular energy levels affect the pace of the clock by extending the period length, suggesting that this pathway could participate in circadian metabolic entrainment. However, this seems to be a mutual interaction, since the TOR pathway components are also under circadian regulation. These results strengthen the role of this signalling pathway as a master sensor of metabolic status, integrating day length and circadian cues to control anabolic processes in the cell, thus promoting plant growth and development. Expanding this knowledge from Arabidopsis thaliana to crops will improve our understanding of the molecular links connecting environmental perception and growth regulation under field conditions.
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Affiliation(s)
| | - Camila Caldana
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
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30
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Scarpin MR, Simmons CH, Brunkard JO. Translating across kingdoms: target of rapamycin promotes protein synthesis through conserved and divergent pathways in plants. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:7016-7025. [PMID: 35770874 PMCID: PMC9664230 DOI: 10.1093/jxb/erac267] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
mRNA translation is the growth rate-limiting step in genome expression. Target of rapamycin (TOR) evolved a central regulatory role in eukaryotes as a signaling hub that monitors nutrient availability to maintain homeostasis and promote growth, largely by increasing the rate of translation initiation and protein synthesis. The dynamic pathways engaged by TOR to regulate translation remain debated even in well-studied yeast and mammalian models, however, despite decades of intense investigation. Recent studies have firmly established that TOR also regulates mRNA translation in plants through conserved mechanisms, such as the TOR-LARP1-5'TOP signaling axis, and through pathways specific to plants. Here, we review recent advances in our understanding of the regulation of mRNA translation in plants by TOR.
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Affiliation(s)
- M Regina Scarpin
- Laboratory of Genetics, University of Wisconsin, Madison, WI, USA
- Department of Plant and Microbial Biology, University of California, Berkeley,CA, USA
- Plant Gene Expression Center, USDA Agricultural Research Service, Albany, CA, USA
| | - Carl H Simmons
- Laboratory of Genetics, University of Wisconsin, Madison, WI, USA
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31
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Meng Y, Zhang N, Li J, Shen X, Sheen J, Xiong Y. TOR kinase, a GPS in the complex nutrient and hormonal signaling networks to guide plant growth and development. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:7041-7054. [PMID: 35781569 PMCID: PMC9664236 DOI: 10.1093/jxb/erac282] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 06/24/2022] [Indexed: 06/01/2023]
Abstract
To survive and sustain growth, sessile plants have developed sophisticated internal signalling networks that respond to various external and internal cues. Despite the central roles of nutrient and hormone signaling in plant growth and development, how hormone-driven processes coordinate with metabolic status remains largely enigmatic. Target of rapamycin (TOR) kinase is an evolutionarily conserved master regulator that integrates energy, nutrients, growth factors, hormones, and stress signals to promote growth in all eukaryotes. Inspired by recent comprehensive systems, chemical, genetic, and genomic studies on TOR in plants, this review discusses a potential role of TOR as a 'global positioning system' that directs plant growth and developmental programs both temporally and spatially by integrating dynamic information in the complex nutrient and hormonal signaling networks. We further evaluate and depict the possible functional and mechanistic models for how a single protein kinase, TOR, is able to recognize, integrate, and even distinguish a plethora of positive and negative input signals to execute appropriate and distinct downstream biological processes via multiple partners and effectors.
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Affiliation(s)
| | | | - Jiatian Li
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
- Haixia Institute of Science and Technology, Plant Synthetic Biology Center, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xuehong Shen
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
- Haixia Institute of Science and Technology, Plant Synthetic Biology Center, Fujian Agriculture and Forestry University, Fuzhou, 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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32
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Henriques R, Calderan-Rodrigues MJ, Luis Crespo J, Baena-González E, Caldana C. Growing of the TOR world. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:6987-6992. [PMID: 36377640 PMCID: PMC9664224 DOI: 10.1093/jxb/erac401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Indexed: 06/16/2023]
Affiliation(s)
- Rossana Henriques
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, T23 TK30, Ireland
- Environmental Research Institute, Lee Road, Cork, T23 XE10, Ireland
| | | | - José Luis Crespo
- Instituto de Bioquimica Vegetal y Fotosintesis, Consejo Superior de Investigaciones Cientificas (CSIC)-Universidad de Sevilla, Sevilla, Spain
| | - Elena Baena-González
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal and GREEN-IT Bioresources for Sustainability, ITQB-NOVA, 2780-157 Oeiras, Portugal
| | - Camila Caldana
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
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33
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Yu Y, Zhong Z, Ma L, Xiang C, Chen J, Huang XY, Xu P, Xiong Y. Sulfate-TOR signaling controls transcriptional reprogramming for shoot apex activation. THE NEW PHYTOLOGIST 2022; 236:1326-1338. [PMID: 36028982 DOI: 10.1111/nph.18441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/14/2022] [Indexed: 06/15/2023]
Abstract
Plants play a primary role for the global sulfur cycle in the earth ecosystems by reduction of inorganic sulfate from the soil to organic sulfur-containing compounds. How plants sense and transduce the sulfate availability to mediate their growth remains largely unclear. The target of rapamycin (TOR) kinase is an evolutionarily conserved master regulator of nutrient sensing and metabolic signaling to control cell proliferation and growth in all eukaryotes. By tissue-specific Western blotting and RNA-sequencing analysis, we investigated sulfate-TOR signal pathway in regulating shoot apex development. Here, we report that inorganic sulfate exhibits high potency activating TOR and cell proliferation to promote true leaf development in Arabidopsis in a glucose-energy parallel pathway. Genetic and metabolite analyses suggest that this sulfate activation of TOR is independent from the sulfate-assimilation process and glucose-energy signaling. Significantly, tissue specific transcriptome analyses uncover previously unknown sulfate-orchestrating genes involved in DNA replication, cell proliferation and various secondary metabolism pathways, which largely depends on TOR signaling. Systematic comparison between the sulfate- and glucose-TOR controlled transcriptome further reveals that TOR kinase, as the central growth integrator, responds to different nutrient signals to control both shared and unique transcriptome networks, therefore, precisely modulates plant proliferation, growth and stress responses.
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Affiliation(s)
- Yongdong Yu
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- Shanghai Key Laboratory of Plant Functional Genomics and Resources, Shanghai Chenshan Botanical Garden, Shanghai, 201602, China
- Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Zhaochen Zhong
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Liuyin Ma
- Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Chengbin Xiang
- Division of Life Sciences and Medicine, Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences at the Microscale, MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science and Technology of China, The Innovation Academy of Seed Design, Chinese Academy of Sciences, Hefei, 230027, China
| | - Jie Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xin-Yuan Huang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ping Xu
- Shanghai Key Laboratory of Plant Functional Genomics and Resources, Shanghai Chenshan Botanical Garden, Shanghai, 201602, China
| | - Yan Xiong
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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34
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Montes C, Wang P, Liao C, Nolan TM, Song G, Clark NM, Elmore JM, Guo H, Bassham DC, Yin Y, Walley JW. Integration of multi-omics data reveals interplay between brassinosteroid and Target of Rapamycin Complex signaling in Arabidopsis. THE NEW PHYTOLOGIST 2022; 236:893-910. [PMID: 35892179 PMCID: PMC9804314 DOI: 10.1111/nph.18404] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 07/16/2022] [Indexed: 06/01/2023]
Abstract
Brassinosteroids (BRs) and Target of Rapamycin Complex (TORC) are two major actors coordinating plant growth and stress responses. Brassinosteroids function through a signaling pathway to extensively regulate gene expression and TORC is known to regulate translation and autophagy. Recent studies have revealed connections between these two pathways, but a system-wide view of their interplay is still missing. We quantified the level of 23 975 transcripts, 11 183 proteins, and 27 887 phosphorylation sites in wild-type Arabidopsis thaliana and in mutants with altered levels of either BRASSINOSTEROID INSENSITIVE 2 (BIN2) or REGULATORY ASSOCIATED PROTEIN OF TOR 1B (RAPTOR1B), two key players in BR and TORC signaling, respectively. We found that perturbation of BIN2 or RAPTOR1B levels affects a common set of gene-products involved in growth and stress responses. Furthermore, we used the multi-omic data to reconstruct an integrated signaling network. We screened 41 candidate genes identified from the reconstructed network and found that loss of function mutants of many of these proteins led to an altered BR response and/or modulated autophagy activity. Altogether, these results establish a predictive network that defines different layers of molecular interactions between BR- or TORC-regulated growth and autophagy.
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Affiliation(s)
- Christian Montes
- Department of Plant Pathology and MicrobiologyIowa State UniversityAmesIA50011USA
| | - Ping Wang
- Department of Genetics, Development and Cell BiologyIowa State UniversityAmesIA50011USA
| | - Ching‐Yi Liao
- Department of Genetics, Development and Cell BiologyIowa State UniversityAmesIA50011USA
| | - Trevor M. Nolan
- Department of Genetics, Development and Cell BiologyIowa State UniversityAmesIA50011USA
- Department of BiologyDuke UniversityDurhamNC27708USA
| | - Gaoyuan Song
- Department of Plant Pathology and MicrobiologyIowa State UniversityAmesIA50011USA
| | - Natalie M. Clark
- Department of Plant Pathology and MicrobiologyIowa State UniversityAmesIA50011USA
| | - J. Mitch Elmore
- Department of Plant Pathology and MicrobiologyIowa State UniversityAmesIA50011USA
- USDA‐ARS Cereal Disease LaboratoryUniversity of MinnesotaSt PaulMN55108USA
| | - Hongqing Guo
- Department of Genetics, Development and Cell BiologyIowa State UniversityAmesIA50011USA
| | - Diane C. Bassham
- Department of Genetics, Development and Cell BiologyIowa State UniversityAmesIA50011USA
| | - Yanhai Yin
- Department of Genetics, Development and Cell BiologyIowa State UniversityAmesIA50011USA
- Plant Sciences InstituteIowa State UniversityAmesIA50011USA
| | - Justin W. Walley
- Department of Plant Pathology and MicrobiologyIowa State UniversityAmesIA50011USA
- Plant Sciences InstituteIowa State UniversityAmesIA50011USA
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Abraham‐Juárez MJ, Busche M, Anderson AA, Lunde C, Winders J, Christensen SA, Hunter CT, Hake S, Brunkard JO. Liguleless narrow and narrow odd dwarf act in overlapping pathways to regulate maize development and metabolism. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 112:881-896. [PMID: 36164819 PMCID: PMC9827925 DOI: 10.1111/tpj.15988] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 08/24/2022] [Accepted: 09/05/2022] [Indexed: 06/16/2023]
Abstract
Narrow odd dwarf (nod) and Liguleless narrow (Lgn) are pleiotropic maize mutants that both encode plasma membrane proteins, cause similar developmental patterning defects, and constitutively induce stress signaling pathways. To investigate how these mutants coordinate maize development and physiology, we screened for protein interactors of NOD by affinity purification. LGN was identified by this screen as a strong candidate interactor, and we confirmed the NOD-LGN molecular interaction through orthogonal experiments. We further demonstrated that LGN, a receptor-like kinase, can phosphorylate NOD in vitro, hinting that they could act in intersecting signal transduction pathways. To test this hypothesis, we generated Lgn-R;nod mutants in two backgrounds (B73 and A619), and found that these mutations enhance each other, causing more severe developmental defects than either single mutation on its own, with phenotypes including very narrow leaves, increased tillering, and failure of the main shoot. Transcriptomic and metabolomic analyses of the single and double mutants in the two genetic backgrounds revealed widespread induction of pathogen defense genes and a shift in resource allocation away from primary metabolism in favor of specialized metabolism. These effects were similar in each single mutant and heightened in the double mutant, leading us to conclude that NOD and LGN act cumulatively in overlapping signaling pathways to coordinate growth-defense tradeoffs in maize.
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Affiliation(s)
- María Jazmín Abraham‐Juárez
- Laboratorio Nacional de Genómica para la BiodiversidadUnidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico NacionalGuanajuato36821Mexico
| | - Michael Busche
- Laboratory of GeneticsUniversity of WisconsinMadisonWisconsin53706USA
| | - Alyssa A. Anderson
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeleyCalifornia94720USA
- Plant Gene Expression CenterUSDA Agricultural Research ServiceAlbanyCalifornia94710USA
| | - China Lunde
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeleyCalifornia94720USA
| | - Jeremy Winders
- Genomics and Bioinformatics Research Unit, US Department of Agriculture‐Agricultural Research ServiceRaleighNorth CarolinaUSA
| | | | - Charles T. Hunter
- Chemistry Research Unit, USDA Agricultural Research ServiceGainesvilleFlorida32608USA
| | - Sarah Hake
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeleyCalifornia94720USA
- Plant Gene Expression CenterUSDA Agricultural Research ServiceAlbanyCalifornia94710USA
| | - Jacob O. Brunkard
- Laboratory of GeneticsUniversity of WisconsinMadisonWisconsin53706USA
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeleyCalifornia94720USA
- Plant Gene Expression CenterUSDA Agricultural Research ServiceAlbanyCalifornia94710USA
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36
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The TOR complex controls ATP levels to regulate actin cytoskeleton dynamics in Arabidopsis. Proc Natl Acad Sci U S A 2022; 119:e2122969119. [PMID: 36095209 PMCID: PMC9499549 DOI: 10.1073/pnas.2122969119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cells must overcome energy shortage, and the ability to do so determines their fate. The ability of cells to coordinate their cellular activities and energy status is therefore important for all living organisms. One of the major energy drains in eukaryotic cells is the constant turnover of the actin cytoskeleton, which consumes ATP during the cycle of polymerization and depolymerization. We report that the TOR complex, a master regulatory hub that integrates cellular energy information to coordinate cell growth and metabolism, controls cellular ATP levels in plant cells. We further elucidate that low ATP levels cause reduced actin dynamics in plant cells. These findings provide insight into how plant cells handle low energy situations. Energy is essential for all cellular functions in a living organism. How cells coordinate their physiological processes with energy status and availability is thus an important question. The turnover of actin cytoskeleton between its monomeric and filamentous forms is a major energy drain in eukaryotic cells. However, how actin dynamics are regulated by ATP levels remain largely unknown in plant cells. Here, we observed that seedlings with impaired functions of target of rapamycin complex 1 (TORC1), either by mutation of the key component, RAPTOR1B, or inhibition of TOR activity by specific inhibitors, displayed reduced sensitivity to actin cytoskeleton disruptors compared to their controls. Consistently, actin filament dynamics, but not organization, were suppressed in TORC1-impaired cells. Subcellular localization analysis and quantification of ATP concentration demonstrated that RAPTOR1B localized at cytoplasm and mitochondria and that ATP levels were significantly reduced in TORC1-impaired plants. Further pharmacologic experiments showed that the inhibition of mitochondrial functions led to phenotypes mimicking those observed in raptor1b mutants at the level of both plant growth and actin dynamics. Exogenous feeding of adenine could partially restore ATP levels and actin dynamics in TORC1-deficient plants. Thus, these data support an important role for TORC1 in coordinating ATP homeostasis and actin dynamics in plant cells.
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Zhang H, Quintana J, Ütkür K, Adrian L, Hawer H, Mayer K, Gong X, Castanedo L, Schulten A, Janina N, Peters M, Wirtz M, Brinkmann U, Schaffrath R, Krämer U. Translational fidelity and growth of Arabidopsis require stress-sensitive diphthamide biosynthesis. Nat Commun 2022; 13:4009. [PMID: 35817801 PMCID: PMC9273596 DOI: 10.1038/s41467-022-31712-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 06/30/2022] [Indexed: 11/09/2022] Open
Abstract
Diphthamide, a post-translationally modified histidine residue of eukaryotic TRANSLATION ELONGATION FACTOR2 (eEF2), is the human host cell-sensitizing target of diphtheria toxin. Diphthamide biosynthesis depends on the 4Fe-4S-cluster protein Dph1 catalyzing the first committed step, as well as Dph2 to Dph7, in yeast and mammals. Here we show that diphthamide modification of eEF2 is conserved in Arabidopsis thaliana and requires AtDPH1. Ribosomal -1 frameshifting-error rates are increased in Arabidopsis dph1 mutants, similar to yeast and mice. Compared to the wild type, shorter roots and smaller rosettes of dph1 mutants result from fewer formed cells. TARGET OF RAPAMYCIN (TOR) kinase activity is attenuated, and autophagy is activated, in dph1 mutants. Under abiotic stress diphthamide-unmodified eEF2 accumulates in wild-type seedlings, most strongly upon heavy metal excess, which is conserved in human cells. In summary, our results suggest that diphthamide contributes to the functionality of the translational machinery monitored by plants to regulate growth.
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Affiliation(s)
- Hongliang Zhang
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitaetsstrasse 150, Box 44 ND3/30, 44801, Bochum, Germany
| | - Julia Quintana
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitaetsstrasse 150, Box 44 ND3/30, 44801, Bochum, Germany
| | - Koray Ütkür
- Microbiology, Institute for Biology, University of Kassel, 34132, Kassel, Germany
| | - Lorenz Adrian
- Environmental Biotechnology, Helmholtz Centre for Environmental Research-UFZ, 04318, Leipzig, Germany.,Chair of Geobiotechnology, Technische Universität Berlin, 13355, Berlin, Germany
| | - Harmen Hawer
- Microbiology, Institute for Biology, University of Kassel, 34132, Kassel, Germany
| | - Klaus Mayer
- Roche Pharma Research & Early Development, Large Molecule Research, Roche Innovation Center Munich, 82377, Penzberg, Germany
| | - Xiaodi Gong
- Centre for Organismal Studies (COS), University of Heidelberg, 69120, Heidelberg, Germany
| | - Leonardo Castanedo
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitaetsstrasse 150, Box 44 ND3/30, 44801, Bochum, Germany
| | - Anna Schulten
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitaetsstrasse 150, Box 44 ND3/30, 44801, Bochum, Germany
| | - Nadežda Janina
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitaetsstrasse 150, Box 44 ND3/30, 44801, Bochum, Germany
| | - Marcus Peters
- Molecular Immunology, Medical Faculty, Ruhr University Bochum, 44801, Bochum, Germany
| | - Markus Wirtz
- Centre for Organismal Studies (COS), University of Heidelberg, 69120, Heidelberg, Germany
| | - Ulrich Brinkmann
- Roche Pharma Research & Early Development, Large Molecule Research, Roche Innovation Center Munich, 82377, Penzberg, Germany
| | - Raffael Schaffrath
- Microbiology, Institute for Biology, University of Kassel, 34132, Kassel, Germany
| | - Ute Krämer
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitaetsstrasse 150, Box 44 ND3/30, 44801, Bochum, Germany.
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RNA-binding proteins and their role in translational regulation in plants. Essays Biochem 2022; 66:87-97. [PMID: 35612383 DOI: 10.1042/ebc20210069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/06/2022] [Accepted: 05/09/2022] [Indexed: 12/16/2022]
Abstract
Translation is a fundamental process for life that needs to be finely adapted to the energetical, developmental and environmental conditions; however, the molecular mechanisms behind such adaptation are not yet fully understood. By directly recognizing and binding to cis-elements present in their target mRNAs, RBPs govern all post-transcriptional regulatory processes. They orchestrate the balance between mRNA stability, storage, decay, and translation of their client mRNAs, playing a crucial role in the modulation of gene expression. In the last years exciting discoveries have been made regarding the roles of RBPs in fine-tuning translation. In this review, we focus on how these RBPs recognize their targets and modulate their translation, highlighting the complex and diverse molecular mechanisms implicated. Since the repertoire of RBPs keeps growing, future research promises to uncover new fascinating means of translational modulation, and thus, of gene expression.
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Zhou J, Qi A, Wang B, Zhang X, Dong Q, Liu J. Integrated Analyses of Transcriptome and Chlorophyll Fluorescence Characteristics Reveal the Mechanism Underlying Saline-Alkali Stress Tolerance in Kosteletzkya pentacarpos. FRONTIERS IN PLANT SCIENCE 2022; 13:865572. [PMID: 35599866 PMCID: PMC9122486 DOI: 10.3389/fpls.2022.865572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 03/28/2022] [Indexed: 06/15/2023]
Abstract
In recent years, soil salinization has become increasingly severe, and the ecological functions of saline-alkali soils have deteriorated because of the lack of plants. Therefore, understanding the tolerance mechanisms of saline-alkali-tolerant plants has become crucial to restore the ecological functions of saline-alkali soils. In this study, we evaluated the molecular mechanism underlying the tolerance of Kosteletzkya pentacarpos L. (seashore mallow) seedlings treated with 0.05 or 0.5% saline-alkali solution (NaCl: NaHCO3 = 4:1 mass ratio) for 1 and 7 days. We identified the key genes involved in tolerance to saline-alkali stress using orthogonal partial least squares regression analysis (OPLS-RA) based on both chlorophyll fluorescence indexes and stress-responsive genes using transcriptome analysis, and, finally, validated their expression using qRT-PCR. We observed minor changes in the maximum photochemical efficiency of the stressed seedlings, whose photosynthetic performance remained stable. Moreover, compared to the control, other indicators varied more evidently on day 7 of 0.5% saline-alkali treatment, but no variations were observed in other treatments. Transcriptome analysis revealed a total of 54,601 full-length sequences, with predominantly downregulated differentially expressed gene (DEG) expression. In the high concentration treatment, the expression of 89.11 and 88.38% of DEGs was downregulated on days 1 and 7, respectively. Furthermore, nine key genes, including KpAGO4, KpLARP1C, and KpPUB33, were involved in negative regulatory pathways, such as siRNA-mediated DNA methylation, inhibition of 5'-terminal oligopyrimidine mRNA translation, ubiquitin/proteasome degradation, and other pathways, including programmed cell death. Finally, quantitative analysis suggested that the expression of key genes was essentially downregulated. Thus, these genes can be used in plant molecular breeding in the future to generate efficient saline-alkali-tolerant plant germplasm resources to improve the ecological functions of saline-alkali landscapes.
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Affiliation(s)
- Jian Zhou
- School of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Center of Horticulture Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Anguo Qi
- School of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Center of Horticulture Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Baoquan Wang
- School of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Center of Horticulture Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Xiaojing Zhang
- School of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
| | - Qidi Dong
- School of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
| | - Jinxiu Liu
- School of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
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40
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Artins A, Caldana C. The metabolic homeostaTOR: The balance of holding on or letting grow. CURRENT OPINION IN PLANT BIOLOGY 2022; 66:102196. [PMID: 35219142 DOI: 10.1016/j.pbi.2022.102196] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/18/2022] [Accepted: 01/23/2022] [Indexed: 06/14/2023]
Abstract
Plants, as autotrophic organisms, capture light energy to convert carbon dioxide into ATP, NADPH, and sugars, which are essential for the biosynthesis of building blocks, cell proliferation, biomass accumulation, and reproductive fitness. The Target Of Rapamycin (TOR) signalling pathway is a master regulator in sensing energy and nutrients, adapting the metabolic network and cell behaviour in response to environmental resource availability. In the past years, exciting advances in this endeavour have pointed out this pathway's importance in controlling metabolic homeostasis in various biological processes and systems. In this review, we discuss these recent discoveries highlighting the need for a metabolic threshold for the proper function of this kinase complex at the cellular level and across distinct tissues and organs to control growth and development in plants.
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Affiliation(s)
- Anthony Artins
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Camila Caldana
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany.
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Wang M, Ogé L, Pérez Garcia MD, Launay-Avon A, Clément G, Le Gourrierec J, Hamama L, Sakr S. Antagonistic Effect of Sucrose Availability and Auxin on Rosa Axillary Bud Metabolism and Signaling, Based on the Transcriptomics and Metabolomics Analysis. FRONTIERS IN PLANT SCIENCE 2022; 13:830840. [PMID: 35392520 PMCID: PMC8982072 DOI: 10.3389/fpls.2022.830840] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 02/02/2022] [Indexed: 06/14/2023]
Abstract
Shoot branching is crucial for successful plant development and plant response to environmental factors. Extensive investigations have revealed the involvement of an intricate regulatory network including hormones and sugars. Recent studies have demonstrated that two major systemic regulators-auxin and sugar-antagonistically regulate plant branching. However, little is known regarding the molecular mechanisms involved in this crosstalk. We carried out two complementary untargeted approaches-RNA-seq and metabolomics-on explant stem buds fed with different concentrations of auxin and sucrose resulting in dormant and non-dormant buds. Buds responded to the combined effect of auxin and sugar by massive reprogramming of the transcriptome and metabolome. The antagonistic effect of sucrose and auxin targeted several important physiological processes, including sink strength, the amino acid metabolism, the sulfate metabolism, ribosome biogenesis, the nucleic acid metabolism, and phytohormone signaling. Further experiments revealed a role of the TOR-kinase signaling pathway in bud outgrowth through at least downregulation of Rosa hybrida BRANCHED1 (RhBRC1). These new findings represent a cornerstone to further investigate the diverse molecular mechanisms that drive the integration of endogenous factors during shoot branching.
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Affiliation(s)
- Ming Wang
- Dryland-Technology Key Laboratory of Shandong Province, College of Agronomy, Qingdao Agricultural University, Qingdao, China
- Institut Agro, University of Angers INRAE, IRHS, SFR QUASAV, Angers, France
| | - Laurent Ogé
- Institut Agro, University of Angers INRAE, IRHS, SFR QUASAV, Angers, France
| | | | - Alexandra Launay-Avon
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, Université Paris-Sud, Université d’Evry, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Gilles Clément
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Jose Le Gourrierec
- Institut Agro, University of Angers INRAE, IRHS, SFR QUASAV, Angers, France
| | - Latifa Hamama
- Institut Agro, University of Angers INRAE, IRHS, SFR QUASAV, Angers, France
| | - Soulaiman Sakr
- Institut Agro, University of Angers INRAE, IRHS, SFR QUASAV, Angers, France
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42
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Coordination of Chloroplast Activity with Plant Growth: Clues Point to TOR. PLANTS 2022; 11:plants11060803. [PMID: 35336685 PMCID: PMC8953291 DOI: 10.3390/plants11060803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 11/17/2022]
Abstract
Photosynthesis is the defining function of most autotrophic organisms. In the plantae kingdom, chloroplasts host this function and ensure growth. However, these organelles are very sensitive to stressful conditions and the photosynthetic process can cause photooxidative damage if not perfectly regulated. In addition, their function is energivorous in terms of both chemical energy and nutrients. To coordinate chloroplast activity with the cell’s need, continuous signaling is required: from chloroplasts to cytoplasm and from nucleus to chloroplasts. In this opinion article, several mechanisms that ensure this communication are reported and the many clues that point to an important role of the Target of Rapamycin (TOR) kinase in the coordination between the eukaryotic and prokaryotic sides of plants are highlighted.
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43
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Amino Acid Signaling for TOR in Eukaryotes: Sensors, Transducers, and a Sustainable Agricultural fuTORe. Biomolecules 2022; 12:biom12030387. [PMID: 35327579 PMCID: PMC8945916 DOI: 10.3390/biom12030387] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/26/2022] [Accepted: 02/28/2022] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic cells monitor and regulate metabolism through the atypical protein kinase target of rapamycin (TOR) regulatory hub. TOR is activated by amino acids in animals and fungi through molecular signaling pathways that have been extensively defined in the past ten years. Very recently, several studies revealed that TOR is also acutely responsive to amino acid metabolism in plants, but the mechanisms of amino acid sensing are not yet established. In this review, we summarize these discoveries, emphasizing the diversity of amino acid sensors in human cells and highlighting pathways that are indirectly sensitive to amino acids, i.e., how TOR monitors changes in amino acid availability without a bona fide amino acid sensor. We then discuss the relevance of these model discoveries to plant biology. As plants can synthesize all proteinogenic amino acids from inorganic precursors, we focus on the possibility that TOR senses both organic metabolites and inorganic nutrients. We conclude that an evolutionary perspective on nutrient sensing by TOR benefits both agricultural and biomedical science, contributing to ongoing efforts to generate crops for a sustainable agricultural future.
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Couso I, Smythers AL, Ford MM, Umen JG, Crespo JL, Hicks LM. Inositol polyphosphates and target of rapamycin kinase signalling govern photosystem II protein phosphorylation and photosynthetic function under light stress in Chlamydomonas. THE NEW PHYTOLOGIST 2021; 232:2011-2025. [PMID: 34529857 DOI: 10.1111/nph.17741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 09/09/2021] [Indexed: 05/28/2023]
Abstract
Stress and nutrient availability influence cell proliferation through complex intracellular signalling networks. In a previous study it was found that pyro-inositol polyphosphates (InsP7 and InsP8 ) produced by VIP1 kinase, and target of rapamycin (TOR) kinase signalling interacted synergistically to control cell growth and lipid metabolism in the green alga Chlamydomonas reinhardtii. However, the relationship between InsPs and TOR was not completely elucidated. We used an in vivo assay for TOR activity together with global proteomic and phosphoproteomic analyses to assess differences between wild-type and vip1-1 in the presence and absence of rapamycin. We found that TOR signalling is more severely affected by the inhibitor rapamycin in a vip1-1 mutant compared with wild-type, indicating that InsP7 and InsP8 produced by VIP1 act independently but also coordinately with TOR. Additionally, among hundreds of differentially phosphorylated peptides detected, an enrichment for photosynthesis-related proteins was observed, particularly photosystem II proteins. The significance of these results was underscored by the finding that vip1-1 strains show multiple defects in photosynthetic physiology that were exacerbated under high light conditions. These results suggest a novel role for inositol pyrophosphates and TOR signalling in coordinating photosystem phosphorylation patterns in Chlamydomonas cells in response to light stress and possibly other stresses.
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Affiliation(s)
- Inmaculada Couso
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla, Avda. Américo Vespucio, 49, Sevilla, 41092, Spain
| | - Amanda L Smythers
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Megan M Ford
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - James G Umen
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
| | - José L Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla, Avda. Américo Vespucio, 49, Sevilla, 41092, Spain
| | - Leslie M Hicks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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Castellano MM, Merchante C. Peculiarities of the regulation of translation initiation in plants. CURRENT OPINION IN PLANT BIOLOGY 2021; 63:102073. [PMID: 34186463 DOI: 10.1016/j.pbi.2021.102073] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/21/2021] [Accepted: 05/27/2021] [Indexed: 06/13/2023]
Abstract
Protein synthesis is a fundamental process for life and, as such, plays a crucial role in the adaptation to energy, developmentaland environmental conditions. For these reasons, and despite the general conservation of the eukaryotic translational machinery, it is not surprising that organisms with different lifestyles have evolved distinct mechanisms of regulation to adapt translation initiation to their intrinsic growth and development. Plants have clear peculiarities compared with other eukaryotes that have also extended to translation control. This review describes the plant-specific mechanisms for regulation of translation initiation, with a focus on those that modulate the eIF4F complexes, central translational regulatory hubs in all eukaryotes, and highlights the latest discoveries on the signaling pathways that regulate their constituents and activity.
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Affiliation(s)
- M Mar Castellano
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA, CSIC), Campus Montegancedo UPM, Pozuelo de Alarcón, Madrid, 28223, Spain.
| | - Catharina Merchante
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Campus de Teatinos, Universidad de Málaga, Málaga, 29071, Spain.
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Riegler S, Servi L, Scarpin MR, Godoy Herz MA, Kubaczka MG, Venhuizen P, Meyer C, Brunkard JO, Kalyna M, Barta A, Petrillo E. Light regulates alternative splicing outcomes via the TOR kinase pathway. Cell Rep 2021; 36:109676. [PMID: 34496244 PMCID: PMC8547716 DOI: 10.1016/j.celrep.2021.109676] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 05/18/2021] [Accepted: 08/16/2021] [Indexed: 11/29/2022] Open
Abstract
For plants, light is the source of energy and the most relevant regulator of growth and adaptations to the environment by inducing changes in gene expression at various levels, including alternative splicing. Light-triggered chloroplast retrograde signals control alternative splicing in Arabidopsis thaliana. Here, we provide evidence that light regulates the expression of a core set of splicing-related factors in roots. Alternative splicing responses in roots are not directly caused by light but are instead most likely triggered by photo-synthesized sugars. The target of rapamycin (TOR) kinase plays a key role in this shoot-to-root signaling pathway. Knocking down TOR expression or pharmacologically inhibiting TOR activity disrupts the alternative splicing responses to light and exogenous sugars in roots. Consistently, splicing decisions are modulated by mitochondrial activity in roots. In conclusion, by activating the TOR pathway, sugars act as mobile signals to coordinate alternative splicing responses to light throughout the whole plant. Riegler et al. reveal a central role for TOR kinase paired with retrograde signaling in alternative splicing regulation by light in roots and, to a certain extent, in leaves. Activating the TOR pathway, sugars act as mobile signals to coordinate alternative splicing responses to light throughout the whole plant.
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Affiliation(s)
- Stefan Riegler
- Department of Applied Genetics and Cell Biology, BOKU - University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Lucas Servi
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología, Molecular, y Celular, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), C1428EHA, Buenos Aires, Argentina
| | - M Regina Scarpin
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Plant Gene Expression Center, US Department of Agriculture, Agricultural Research Service, Albany, CA 94710, USA
| | - Micaela A Godoy Herz
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología, Molecular, y Celular, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), C1428EHA, Buenos Aires, Argentina
| | - María G Kubaczka
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología, Molecular, y Celular, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), C1428EHA, Buenos Aires, Argentina
| | - Peter Venhuizen
- Department of Applied Genetics and Cell Biology, BOKU - University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Christian Meyer
- Institut Jean-Pierre Bourgin, Institut National de la Recherche Agronomique, AgroParisTech, Centre National de la Recherche Scientifique, Université Paris-Saclay, Versailles, France
| | - Jacob O Brunkard
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Plant Gene Expression Center, US Department of Agriculture, Agricultural Research Service, Albany, CA 94710, USA; Laboratory of Genetics, University of Wisconsin, Madison, Madison, WI 53706, USA
| | - Maria Kalyna
- Department of Applied Genetics and Cell Biology, BOKU - University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Andrea Barta
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter Campus, 1030 Vienna, Austria
| | - Ezequiel Petrillo
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología, Molecular, y Celular, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), C1428EHA, Buenos Aires, Argentina.
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Abstract
Nutrients are vital to life through intertwined sensing, signaling, and metabolic processes. Emerging research focuses on how distinct nutrient signaling networks integrate and coordinate gene expression, metabolism, growth, and survival. We review the multifaceted roles of sugars, nitrate, and phosphate as essential plant nutrients in controlling complex molecular and cellular mechanisms of dynamic signaling networks. Key advances in central sugar and energy signaling mechanisms mediated by the evolutionarily conserved master regulators HEXOKINASE1 (HXK1), TARGET OF RAPAMYCIN (TOR), and SNF1-RELATED PROTEIN KINASE1 (SNRK1) are discussed. Significant progress in primary nitrate sensing, calcium signaling, transcriptome analysis, and root-shoot communication to shape plant biomass and architecture are elaborated. Discoveries on intracellular and extracellular phosphate signaling and the intimate connections with nitrate and sugar signaling are examined. This review highlights the dynamic nutrient, energy, growth, and stress signaling networks that orchestrate systemwide transcriptional, translational, and metabolic reprogramming, modulate growth and developmental programs, and respond to environmental cues. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 37 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Lei Li
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114, USA; ,
| | - Kun-Hsiang Liu
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114, USA; , .,State Key Laboratory of Crop Stress Biology for Arid Areas, College of Life Sciences, and Institute of Future Agriculture, Northwest Agriculture & Forestry University, Yangling, Shaanxi 712100, China
| | - Jen Sheen
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114, USA; ,
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Busche M, Scarpin MR, Hnasko R, Brunkard JO. TOR coordinates nucleotide availability with ribosome biogenesis in plants. THE PLANT CELL 2021; 33:1615-1632. [PMID: 33793860 PMCID: PMC8254494 DOI: 10.1093/plcell/koab043] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 01/29/2021] [Indexed: 05/10/2023]
Abstract
TARGET OF RAPAMYCIN (TOR) is a conserved eukaryotic Ser/Thr protein kinase that coordinates growth and metabolism with nutrient availability. We conducted a medium-throughput functional genetic screen to discover essential genes that promote TOR activity in plants, and identified a critical regulatory enzyme, cytosolic phosphoribosyl pyrophosphate (PRPP) synthetase (PRS4). PRS4 synthesizes cytosolic PRPP, a key upstream metabolite in nucleotide synthesis and salvage pathways. We found that prs4 knockouts are embryo-lethal in Arabidopsis thaliana, and that silencing PRS4 expression in Nicotiana benthamiana causes pleiotropic developmental phenotypes, including dwarfism, aberrant leaf shape, and delayed flowering. Transcriptomic analysis revealed that ribosome biogenesis is among the most strongly repressed processes in prs4 knockdowns. Building on these results, we discovered that TOR activity is inhibited by chemical or genetic disruption of nucleotide biosynthesis, but that this effect can be reversed by supplying plants with nucleobases. Finally, we show that TOR transcriptionally promotes nucleotide biosynthesis to support the demands of ribosomal RNA synthesis. We propose that TOR coordinates ribosome biogenesis with nucleotide availability in plants to maintain metabolic homeostasis and support growth.
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Affiliation(s)
- Michael Busche
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
- Plant Gene Expression Center, USDA Agricultural Research Service, Albany, CA 94710, USA
| | - M Regina Scarpin
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
- Plant Gene Expression Center, USDA Agricultural Research Service, Albany, CA 94710, USA
| | - Robert Hnasko
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Pacific West Area, USDA Agricultural Research Service, Albany, CA 94710,USA
| | - Jacob O Brunkard
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
- Plant Gene Expression Center, USDA Agricultural Research Service, Albany, CA 94710, USA
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49
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Pacheco JM, Canal MV, Pereyra CM, Welchen E, Martínez-Noël GMA, Estevez JM. The tip of the iceberg: emerging roles of TORC1, and its regulatory functions in plant cells. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4085-4101. [PMID: 33462577 DOI: 10.1093/jxb/eraa603] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 12/19/2020] [Indexed: 06/12/2023]
Abstract
Target of Rapamycin (TOR) is an evolutionarily conserved protein kinase that plays a central role in coordinating cell growth with light availability, the diurnal cycle, energy availability, and hormonal pathways. TOR Complex 1 (TORC1) controls cell proliferation, growth, metabolism, and defense in plants. Sugar availability is the main signal for activation of TOR in plants, as it also is in mammals and yeast. Specific regulators of the TOR kinase pathway in plants are inorganic compounds in the form of major nutrients in the soils, and light inputs via their impact on autotrophic metabolism. The lack of TOR is embryo-lethal in plants, whilst dysregulation of TOR signaling causes major alterations in growth and development. TOR exerts control as a regulator of protein translation via the action of proteins such as S6K, RPS6, and TAP46. Phytohormones are central players in the downstream systemic physiological TOR effects. TOR has recently been attributed to have roles in the control of DNA methylation, in the abundance of mRNA splicing variants, and in the variety of regulatory lncRNAs and miRNAs. In this review, we summarize recent discoveries in the plant TOR signaling pathway in the context of our current knowledge of mammalian and yeast cells, and highlight the most important gaps in our understanding of plants that need to be addressed in the future.
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Affiliation(s)
| | - María Victoria Canal
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas,, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - Cintia M Pereyra
- Instituto de Investigaciones en Biodiversidad y Biotecnología (INBIOTEC-CONICET) and Fundación para Investigaciones Biológicas Aplicadas (FIBA), Vieytes, Mar Del Plata, Argentina
| | - Elina Welchen
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas,, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - Giselle M A Martínez-Noël
- Instituto de Investigaciones en Biodiversidad y Biotecnología (INBIOTEC-CONICET) and Fundación para Investigaciones Biológicas Aplicadas (FIBA), Vieytes, Mar Del Plata, Argentina
| | - José M Estevez
- Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires CP, Argentina
- Centro de Biotecnología Vegetal (CBV), Facultad de Ciencias de la Vida (FCsV), Universidad Andres Bello, Santiago, Chile and Millennium Institute for Integrative Biology (iBio), Santiago, Chile
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50
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Zhou L, Vejlupkova Z, Warman C, Fowler JE. A Maize Male Gametophyte-Specific Gene Encodes ZmLARP6c1, a Potential RNA-Binding Protein Required for Competitive Pollen Tube Growth. FRONTIERS IN PLANT SCIENCE 2021; 12:635244. [PMID: 33719310 PMCID: PMC7947365 DOI: 10.3389/fpls.2021.635244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
Members of the La-related protein family (LARPs) contain a conserved La module, which has been associated with RNA-binding activity. Expression of the maize gene GRMZM2G323499/Zm00001d018613, a member of the LARP family, is highly specific to pollen, based on both transcriptomic and proteomic assays. This suggests a pollen-specific RNA regulatory function for the protein, designated ZmLARP6c1 based on sequence similarity to the LARP6 subfamily in Arabidopsis. To test this hypothesis, a Ds-GFP transposable element insertion in the ZmLarp6c1 gene (tdsgR82C05) was obtained from the Dooner/Du mutant collection. Sequencing confirmed that the Ds-GFP insertion is in an exon, and thus likely interferes with ZmLARP6c1 function. Tracking inheritance of the insertion via its endosperm-expressed GFP indicated that the mutation was associated with reduced transmission from a heterozygous plant when crossed as a male (ranging from 0.5 to 26.5% transmission), but not as a female. Furthermore, this transmission defect was significantly alleviated when less pollen was applied to the silk, reducing competition between mutant and wild-type pollen. Pollen grain diameter measurements and nuclei counts showed no significant differences between wild-type and mutant pollen. However, in vitro, mutant pollen tubes were significantly shorter than those from sibling wild-type plants, and also displayed altered germination dynamics. These results are consistent with the idea that ZmLARP6c1 provides an important regulatory function during the highly competitive progamic phase of male gametophyte development following arrival of the pollen grain on the silk. The conditional, competitive nature of the Zmlarp6c1::Ds male sterility phenotype (i.e., reduced ability to produce progeny seed) points toward new possibilities for genetic control of parentage in crop production.
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Affiliation(s)
- Lian Zhou
- Maize Research Institute, College of Agronomy and Biotechnology, Southwest University, Chongqing, China
| | - Zuzana Vejlupkova
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Cedar Warman
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - John E Fowler
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
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