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Moin M, Saha A, Bakshi A, Madhav MS, Kirti PB. Constitutive expression of Ribosomal Protein L6 modulates salt tolerance in rice transgenic plants. Gene 2021; 789:145670. [PMID: 33892070 DOI: 10.1016/j.gene.2021.145670] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/14/2021] [Accepted: 04/15/2021] [Indexed: 12/17/2022]
Abstract
We have functionally characterized the RPL6, a Ribosomal Protein Large subunit gene for salt stress tolerance in rice. The overexpression of RPL6 resulted in tolerance to moderate (150 mM) to high (200 mM) levels of salt (NaCl). The transgenic rice plants expressing RPL6 constitutively showed better phenotypic and physiological responses with high quantum efficiency, accumulation of higher chlorophyll and proline contents, and an overall increase in seed yield compared with the wild type in salt stress treatments. An iTRAQ-based comparative proteomic analysis revealed the high expression of about 333 proteins among the 4378 DAPs in a selected overexpression line of RPL6 treated with 200 mM of NaCl. The functional analysis showed that these highly accumulated proteins (HAPs) are involved in photosynthesis, ribosome and chloroplast biogenesis, ion transportation, transcription and translation regulation, phytohormone and secondary metabolite signal transduction. An in silico network analysis of HAPs predicted that RPL6 binds with translation-related proteins and helicases, which coordinately affect the activities of a comprehensive signaling network, thereby inducing tolerance and promoting growth and productivity in response to salt stress. Our overall findings identified a novel candidate, RPL6, whose characterization contributed to the existing knowledge on the complexity of salt tolerance mechanism in plants.
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Affiliation(s)
- Mazahar Moin
- Biotechnology Division, ICAR-Indian Institute of Rice Research (IIRR), Hyderabad 500030, India.
| | - Anusree Saha
- Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Achala Bakshi
- Biotechnology Division, ICAR-Indian Institute of Rice Research (IIRR), Hyderabad 500030, India
| | - M S Madhav
- Biotechnology Division, ICAR-Indian Institute of Rice Research (IIRR), Hyderabad 500030, India
| | - P B Kirti
- Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, India; Agri-Biotech Foundation, PJTS Agricultural University, Hyderabad 500030, India
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da Silva VCH, Martins MCM, Calderan-Rodrigues MJ, Artins A, Monte Bello CC, Gupta S, Sobreira TJP, Riaño-Pachón DM, Mafra V, Caldana C. Shedding Light on the Dynamic Role of the "Target of Rapamycin" Kinase in the Fast-Growing C 4 Species Setaria viridis, a Suitable Model for Biomass Crops. FRONTIERS IN PLANT SCIENCE 2021; 12:637508. [PMID: 33927734 PMCID: PMC8078139 DOI: 10.3389/fpls.2021.637508] [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: 12/03/2020] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
The Target of Rapamycin (TOR) kinase pathway integrates energy and nutrient availability into metabolism promoting growth in eukaryotes. The overall higher efficiency on nutrient use translated into faster growth rates in C4 grass plants led to the investigation of differential transcriptional and metabolic responses to short-term chemical TOR complex (TORC) suppression in the model Setaria viridis. In addition to previously described responses to TORC inhibition (i.e., general growth arrest, translational repression, and primary metabolism reprogramming) in Arabidopsis thaliana (C3), the magnitude of changes was smaller in S. viridis, particularly regarding nutrient use efficiency and C allocation and partitioning that promote biosynthetic growth. Besides photosynthetic differences, S. viridis and A. thaliana present several specificities that classify them into distinct lineages, which also contribute to the observed alterations mediated by TOR. Indeed, cell wall metabolism seems to be distinctly regulated according to each cell wall type, as synthesis of non-pectic polysaccharides were affected in S. viridis, whilst assembly and structure in A. thaliana. Our results indicate that the metabolic network needed to achieve faster growth seems to be less stringently controlled by TORC in S. viridis.
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Affiliation(s)
| | | | | | - Anthony Artins
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | | | - Saurabh Gupta
- Institute of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany
| | | | | | - Valéria Mafra
- National Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Camila Caldana
- National Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
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Upadhyaya S, Rao BJ. Reciprocal regulation of photosynthesis and mitochondrial respiration by TOR kinase in Chlamydomonas reinhardtii. PLANT DIRECT 2019; 3:e00184. [PMID: 31832599 PMCID: PMC6854518 DOI: 10.1002/pld3.184] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 10/21/2019] [Accepted: 10/29/2019] [Indexed: 05/03/2023]
Abstract
While the role of TOR kinase in the chloroplast biogenesis and transcriptional regulation of photosynthesis is well documented in Arabidopsis, the functional relevance of this metabolic sensor kinase in chloroplast-mitochondria cross talk is unknown. Using Chlamydomonas reinhardtii as the model system, we demonstrate the role of TOR kinase in the regulation of chloroplast and mitochondrial functions: We show that TOR kinase inhibition impairs the maintenance of high ETR associated with PSII and low NPQ and inhibits efficient state transitions between PSII and PSI. While compromised photosynthetic functions are observed in TOR kinase inhibited cells, same conditions lead to augmentation in mitochondrial basal respiration rate by twofold and concomitantly a rise in ATP production. Interestingly, such upregulated mitochondrial functions in TOR-inhibited cells are mediated by fragmented mitochondria via upregulating COXIIb and downregulating Hxk1 and AOX1 protein levels. We propose that TOR kinase may act as a sensor that counter-regulates chloroplast versus mitochondrial functions in a normal C. reinhardtii cell.
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Affiliation(s)
- Shivani Upadhyaya
- Department of Biological SciencesTata Institute of Fundamental Research (TIFR)MumbaiIndia
| | - Basuthkar Jagadeeshwar Rao
- Indian Institute of Science Education and Research (IISER) TirupatiTransit Campus: Sree Rama Engineering CollegeTirupatiIndia
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Yuan S, Kim SC, Deng X, Hong Y, Wang X. Diacylglycerol kinase and associated lipid mediators modulate rice root architecture. THE NEW PHYTOLOGIST 2019; 223:261-276. [PMID: 30887532 DOI: 10.1111/nph.15801] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 03/08/2019] [Indexed: 05/07/2023]
Abstract
Diacylglycerol kinase (DGK) phosphorylates diacylglycerol (DAG) to generate phosphatidic acid (PA), and both DAG and PA are lipid mediators in the cell. Here we show that DGK1 in rice (Oryza sativa) plays important roles in root growth and development. Two independent OsDGK1-knockout (dgk1) lines exhibited a higher density of lateral roots (LRs) and thinner seminal roots (SRs), whereas OsDGK1-overexpressing plants displayed a lower LR density and thicker SRs than wild-type (WT) plants. Overexpression of OsDGK1 led to a decline in the DGK substrate DAG whereas specific PA species decreased in dgk1 roots. Supplementation of DAG to OsDGK1-overexpressing seedlings restored the LR density and SR thickness whereas application of PA to dgk1 seedlings restored the LR density and SR thickness to those of the WT. In addition, treatment of rice seedlings with the DGK inhibitor R59022 increased the level of DAG and decreased PA, which also restored the root phenotype of OsDGK1-overexpressing seedlings close to that of the WT. Together, these results indicate that DGK1 and associated lipid mediators modulate rice root architecture; DAG promotes LR formation and suppresses SR growth whereas PA suppresses LR number and promotes SR thickness.
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Affiliation(s)
- Shu Yuan
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
- Department of Biology, University of Missouri, St Louis, MO, 63121, USA
| | - Sang-Chul Kim
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
- Department of Biology, University of Missouri, St Louis, MO, 63121, USA
| | - Xianjun Deng
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yueyun Hong
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xuemin Wang
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
- Department of Biology, University of Missouri, St Louis, MO, 63121, USA
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Bakshi A, Moin M, Madhav MS, Kirti PB. Target of rapamycin, a master regulator of multiple signalling pathways and a potential candidate gene for crop improvement. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:190-205. [PMID: 30411830 DOI: 10.1111/plb.12935] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 11/05/2018] [Indexed: 06/08/2023]
Abstract
The target of rapamycin (TOR) protein regulates growth and development in photosynthetic and non-photosynthetic eukaryotes. Although the TOR regulatory networks are involved in nutrient and energy signalling, and transcriptional and translational control of multiple signalling pathways, the molecular mechanism of TOR regulation of plant abiotic stress responses is still unclear. The TOR-mediated transcriptional regulation of genes encoding ribosomal proteins (RP) is a necessity under stress conditions for balanced growth and productivity in plants. The activation of SnRKs (sucrose non-fermenting-related kinases) and the inactivation of TOR signalling in abiotic stresses is in line with the accumulation of ABA and transcriptional activation of stress responsive genes. Autophagy is induced under abiotic stress conditions, which results in degradation of proteins and the release of amino acids, which might possibly induce phosphorylation of TOR and, hence, its activation. TOR signalling also has a role in regulating ABA biosynthesis for transcriptional regulation of stress-related genes. The switch between activation and inactivation of TOR by its phosphorylation and de-phosphorylation maintains balanced growth in response to stresses. In the present review, we discuss the important signalling pathways that are regulated by TOR and try to assess the relationship between TOR signalling and tolerance to abiotic stresses in plants. The review also discusses possible cross-talk between TOR and RP genes in response to abiotic stresses.
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Affiliation(s)
- A Bakshi
- Department of Plant Sciences, University of Hyderabad, Hyderabad, India
| | - M Moin
- Department of Biotechnology, Indian Institute of Rice Research, Hyderabad, India
| | - M S Madhav
- Department of Biotechnology, Indian Institute of Rice Research, Hyderabad, India
| | - P B Kirti
- Department of Plant Sciences, University of Hyderabad, Hyderabad, India
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