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Vijayan J, Alvarez S, Naldrett MJ, Morse W, Maliva A, Wase N, Riekhof WR. Nitrogen starvation leads to TOR kinase-mediated downregulation of fatty acid synthesis in the algae Chlorella sorokiniana and Chlamydomonas reinhardtii. BMC PLANT BIOLOGY 2024; 24:753. [PMID: 39107711 PMCID: PMC11302099 DOI: 10.1186/s12870-024-05408-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 07/11/2024] [Indexed: 08/10/2024]
Abstract
BACKGROUND When subject to stress conditions such as nutrient limitation microalgae accumulate triacylglycerol (TAG). Fatty acid, a substrate for TAG synthesis is derived from de novo synthesis or by membrane remodeling. The model industrial alga Chlorellasorokiniana accumulates TAG and other storage compounds under nitrogen (N)-limited growth. Molecular mechanisms underlying these processes are still to be elucidated. RESULT Previously we used transcriptomics to explore the regulation of TAG synthesis in C. sorokiniana. Surprisingly, our analysis showed that the expression of several key genes encoding enzymes involved in plastidic fatty acid synthesis are significantly repressed. Metabolic labeling with radiolabeled acetate showed that de novo fatty acid synthesis is indeed downregulated under N-limitation. Likewise, inhibition of the Target of Rapamycin kinase (TOR), a key regulator of metabolism and growth, decreased fatty acid synthesis. We compared the changes in proteins and phosphoprotein abundance using a proteomics and phosphoproteomics approach in C. sorokiniana cells under N-limitation or TOR inhibition and found extensive overlap between the N-limited and TOR-inhibited conditions. We also identified changes in the phosphorylation status of TOR complex proteins, TOR-kinase, and RAPTOR, under N-limitation. This indicates that TOR signaling is altered in a nitrogen-dependent manner. We find that TOR-mediated metabolic remodeling of fatty acid synthesis under N-limitation is conserved in the chlorophyte algae Chlorella sorokiniana and Chlamydomonas reinhardtii. CONCLUSION Our results indicate that under N-limitation there is significant metabolic remodeling, including fatty acid synthesis, mediated by TOR signaling. This process is conserved across chlorophyte algae. Using proteomic and phosphoproteomic analysis, we show that N-limitation affects TOR signaling and this in-turn affects the metabolic status of the cells. This study presents a link between N-limitation, TOR signaling and fatty acid synthesis in green-lineage.
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Affiliation(s)
- Jithesh Vijayan
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA.
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, USA.
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, USA.
| | - Sophie Alvarez
- Proteomics and Metabolomics Facility, Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Michael J Naldrett
- Proteomics and Metabolomics Facility, Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Wyatt Morse
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Amanda Maliva
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | | | - Wayne R Riekhof
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
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Wang J, Luo Q, Liang X, Liu H, Wu C, Fang H, Zhang X, Ding S, Yu J, Shi K. Glucose-G protein signaling plays a crucial role in tomato resilience to high temperature and elevated CO2. PLANT PHYSIOLOGY 2024; 195:1025-1037. [PMID: 38447060 DOI: 10.1093/plphys/kiae136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 12/15/2023] [Accepted: 01/05/2024] [Indexed: 03/08/2024]
Abstract
Global climate change is accompanied by carbon dioxide (CO2) enrichment and high temperature (HT) stress; however, how plants adapt to the combined environments and the underlying mechanisms remain largely unclear. In this study, we show that elevated CO2 alleviated plant sensitivity to HT stress, with significantly increased apoplastic glucose (Glc) levels in tomato (Solanum lycopersicum) leaves. Exogenous Glc treatment enhanced tomato resilience to HT stress under ambient CO2 conditions. Cell-based biolayer interferometry, subcellular localization, and Split-luciferase assays revealed that Glc bound to the tomato regulator of G protein signaling 1 (RGS1) and induced RGS1 endocytosis and thereby RGS1-G protein α subunit (GPA1) dissociation in a concentration-dependent manner. Using rgs1 and gpa1 mutants, we found that RGS1 negatively regulated thermotolerance and was required for elevated CO2-Glc-induced thermotolerance. GPA1 positively regulated the elevated CO2-Glc-induced thermotolerance. A combined transcriptome and chlorophyll fluorescence parameter analysis further revealed that GPA1 integrated photosynthesis- and photoprotection-related mechanisms to regulate thermotolerance. These results demonstrate that Glc-RGS1-GPA1 signaling plays a crucial role in the elevated CO2-induced thermotolerance in tomato. This information enhances our understanding of the Glc-G protein signaling function in stress resilience in response to global climate change and will be helpful for genetic engineering approaches to improve plant resilience.
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Affiliation(s)
- Jiao Wang
- Department of Horticulture, Zhejiang University, Hangzhou 310058, China
| | - Qian Luo
- Department of Horticulture, Zhejiang University, Hangzhou 310058, China
| | - Xiao Liang
- Department of Horticulture, Zhejiang University, Hangzhou 310058, China
| | - Hua Liu
- Department of Horticulture, Zhejiang University, Hangzhou 310058, China
| | - Changqi Wu
- Department of Horticulture, Zhejiang University, Hangzhou 310058, China
| | - Hanmo Fang
- Department of Horticulture, Zhejiang University, Hangzhou 310058, China
| | - Xuanbo Zhang
- Department of Horticulture, Zhejiang University, Hangzhou 310058, China
| | - Shuting Ding
- Department of Horticulture, Zhejiang University, Hangzhou 310058, China
| | - Jingquan Yu
- Department of Horticulture, Zhejiang University, Hangzhou 310058, China
- Hainan Institute, Zhejiang University, Sanya 572025, China
| | - Kai Shi
- Department of Horticulture, Zhejiang University, Hangzhou 310058, China
- Hainan Institute, Zhejiang University, Sanya 572025, China
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Duan Q, Lin YR. Focus on vegetable crops. PLANT PHYSIOLOGY 2024; 195:901-905. [PMID: 38688010 PMCID: PMC11142333 DOI: 10.1093/plphys/kiae246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2024] [Revised: 04/27/2024] [Accepted: 04/27/2024] [Indexed: 05/02/2024]
Affiliation(s)
- Qiaohong Duan
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an, Shandong 271018, China
| | - Yann-rong Lin
- Department of Agronomy, National Taiwan University, Taipei 10617, Taiwan
- World Vegetable Center, Headquarters, Shanhua, Tainan 74151, Taiwan
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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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Reichelt N, Korte A, Krischke M, Mueller MJ, Maag D. Natural variation of warm temperature-induced raffinose accumulation identifies TREHALOSE-6-PHOSPHATE SYNTHASE 1 as a modulator of thermotolerance. PLANT, CELL & ENVIRONMENT 2023; 46:3392-3404. [PMID: 37427798 DOI: 10.1111/pce.14664] [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: 04/21/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/11/2023]
Abstract
High-temperature stress limits plant growth and reproduction. Exposure to high temperature, however, also elicits a physiological response, which protects plants from the damage evoked by heat. This response involves a partial reconfiguration of the metabolome including the accumulation of the trisaccharide raffinose. In this study, we explored the intraspecific variation of warm temperature-induced raffinose accumulation as a metabolic marker for temperature responsiveness with the aim to identify genes that contribute to thermotolerance. By combining raffinose measurements in 250 Arabidopsis thaliana accessions following a mild heat treatment with genome-wide association studies, we identified five genomic regions that were associated with the observed trait variation. Subsequent functional analyses confirmed a causal relationship between TREHALOSE-6-PHOSPHATE SYNTHASE 1 (TPS1) and warm temperature-dependent raffinose synthesis. Moreover, complementation of the tps1-1 null mutant with functionally distinct TPS1 isoforms differentially affected carbohydrate metabolism under more severe heat stress. While higher TPS1 activity was associated with reduced endogenous sucrose levels and thermotolerance, disruption of trehalose 6-phosphate signalling resulted in higher accumulation of transitory starch and sucrose and was associated with enhanced heat resistance. Taken together, our findings suggest a role of trehalose 6-phosphate in thermotolerance, most likely through its regulatory function in carbon partitioning and sucrose homoeostasis.
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Affiliation(s)
- Niklas Reichelt
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institute of Biosciences, University of Würzburg, Würzburg, Germany
| | - Arthur Korte
- Center for Computational and Theoretical Biology, University of Würzburg, Würzburg, Germany
| | - Markus Krischke
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institute of Biosciences, University of Würzburg, Würzburg, Germany
| | - Martin J Mueller
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institute of Biosciences, University of Würzburg, Würzburg, Germany
| | - Daniel Maag
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institute of Biosciences, University of Würzburg, Würzburg, Germany
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Caldana C, Fernie AR. Plant biology: Identification of the connecTOR linking metabolism, epigenetics and development. Curr Biol 2022; 32:R1272-R1274. [PMID: 36413970 DOI: 10.1016/j.cub.2022.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
While metabolism has been recognized as a key regulator of plant development, exactly how this is achieved is unknown. A new study identifies a component of the Polycomb repressor complex 2 as linking these processes via histone modification.
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Affiliation(s)
- Camila Caldana
- Max-Planck-Institute of Molecular Plant Physiology, 14467 Potsdam-Golm, Germany
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, 14467 Potsdam-Golm, Germany.
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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)
| | | | - 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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