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Pérez-López J, Feria AB, Gandullo J, de la Osa C, Jiménez-Guerrero I, Echevarría C, Monreal JA, García-Mauriño S. Silencing of Sb PPCK1-3 Negatively Affects Development, Stress Responses and Productivity in Sorghum. PLANTS (BASEL, SWITZERLAND) 2023; 12:2426. [PMID: 37446987 DOI: 10.3390/plants12132426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/20/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023]
Abstract
Phosphoenolpyruvate carboxylase (PEPC) plays central roles in photosynthesis, respiration, amino acid synthesis, and seed development. PEPC is regulated by different post-translational modifications. Between them, the phosphorylation by PEPC-kinase (PEPCk) is widely documented. In this work, we simultaneously silenced the three sorghum genes encoding PEPCk (SbPPCK1-3) by RNAi interference, obtaining 12 independent transgenic lines (Ppck1-12 lines), showing different degrees of SbPPCK1-3 silencing. Among them, two T2 homozygous lines (Ppck-2 and Ppck-4) were selected for further evaluation. Expression of SbPPCK1 was reduced by 65% and 83% in Ppck-2 and Ppck-4 illuminated leaves, respectively. Expression of SbPPCK2 was higher in roots and decreased by 50% in Ppck-2 and Ppck-4 in this tissue. Expression of SbPPCK3 was low and highly variable. Despite the incomplete gene silencing, it decreased the degree of phosphorylation of PEPC in illuminated leaves, P-deficient plants, and NaCl-treated plants. Both leaves and seeds of Ppck lines had altered metabolic profiles and a general decrease in amino acid content. In addition, Ppck lines showed delayed flowering, and 20% of Ppck-4 plants did not produce flowers at all. The total amount of seeds was lowered by 50% and 36% in Ppck-2 and Ppck-4 lines, respectively. The quality of seeds was lower in Ppck lines: lower amino acid content, including Lys, and higher phytate content. These data confirm the relevance of the phosphorylation of PEPC in sorghum development, stress responses, yield, and quality of seeds.
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Affiliation(s)
- Jesús Pérez-López
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012 Seville, Spain
| | - Ana B Feria
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012 Seville, Spain
| | - Jacinto Gandullo
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012 Seville, Spain
| | - Clara de la Osa
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012 Seville, Spain
| | - Irene Jiménez-Guerrero
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012 Seville, Spain
| | - Cristina Echevarría
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012 Seville, Spain
| | - José A Monreal
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012 Seville, Spain
| | - Sofía García-Mauriño
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012 Seville, Spain
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de la Osa C, Pérez‐López J, Feria A, Baena G, Marino D, Coleto I, Pérez‐Montaño F, Gandullo J, Echevarría C, García‐Mauriño S, Monreal JA. Knock-down of phosphoenolpyruvate carboxylase 3 negatively impacts growth, productivity, and responses to salt stress in sorghum (Sorghum bicolor L.). THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:231-249. [PMID: 35488514 PMCID: PMC9539949 DOI: 10.1111/tpj.15789] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 04/21/2022] [Accepted: 04/25/2022] [Indexed: 06/14/2023]
Abstract
Phosphoenolpyruvate carboxylase (PEPC) is a carboxylating enzyme with important roles in plant metabolism. Most studies in C4 plants have focused on photosynthetic PEPC, but less is known about non-photosynthetic PEPC isozymes, especially with respect to their physiological functions. In this work, we analyzed the precise roles of the sorghum (Sorghum bicolor) PPC3 isozyme by the use of knock-down lines with the SbPPC3 gene silenced (Ppc3 lines). Ppc3 plants showed reduced stomatal conductance and plant size, a delay in flowering time, and reduced seed production. In addition, silenced plants accumulated stress indicators such as Asn, citrate, malate, and sucrose in roots and showed higher citrate synthase activity, even in control conditions. Salinity further affected stomatal conductance and yield and had a deeper impact on central metabolism in silenced plants compared to wild type, more notably in roots, with Ppc3 plants showing higher nitrate reductase and NADH-glutamate synthase activity in roots and the accumulation of molecules with a higher N/C ratio. Taken together, our results show that although SbPPC3 is predominantly a root protein, its absence causes deep changes in plant physiology and metabolism in roots and leaves, negatively affecting maximal stomatal opening, growth, productivity, and stress responses in sorghum plants. The consequences of SbPPC3 silencing suggest that this protein, and maybe orthologs in other plants, could be an important target to improve plant growth, productivity, and resistance to salt stress and other stresses where non-photosynthetic PEPCs may be implicated.
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Affiliation(s)
- Clara de la Osa
- Departamento de Biología Vegetal y Ecología, Facultad de BiologíaUniversidad de SevillaSevillaSpain
| | - Jesús Pérez‐López
- Departamento de Biología Vegetal y Ecología, Facultad de BiologíaUniversidad de SevillaSevillaSpain
| | - Ana‐Belén Feria
- Departamento de Biología Vegetal y Ecología, Facultad de BiologíaUniversidad de SevillaSevillaSpain
| | - Guillermo Baena
- Departamento de Biología Vegetal y Ecología, Facultad de BiologíaUniversidad de SevillaSevillaSpain
| | - Daniel Marino
- Departamento de Biología Vegetal y Ecología, Facultad de Ciencia y TecnologíaUniversidad del País Vasco (UPV/EHU)LeioaSpain
- IkerbasqueBasque Foundation for ScienceBilbaoSpain
| | - Inmaculada Coleto
- Departamento de Biología Vegetal y Ecología, Facultad de Ciencia y TecnologíaUniversidad del País Vasco (UPV/EHU)LeioaSpain
| | | | - Jacinto Gandullo
- Departamento de Biología Vegetal y Ecología, Facultad de BiologíaUniversidad de SevillaSevillaSpain
| | - Cristina Echevarría
- Departamento de Biología Vegetal y Ecología, Facultad de BiologíaUniversidad de SevillaSevillaSpain
| | - Sofía García‐Mauriño
- Departamento de Biología Vegetal y Ecología, Facultad de BiologíaUniversidad de SevillaSevillaSpain
| | - José A. Monreal
- Departamento de Biología Vegetal y Ecología, Facultad de BiologíaUniversidad de SevillaSevillaSpain
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Gandullo J, Álvarez R, Feria AB, Monreal JA, Díaz I, Vidal J, Echevarría C. A conserved C-terminal peptide of sorghum phosphoenolpyruvate carboxylase promotes its proteolysis, which is prevented by Glc-6P or the phosphorylation state of the enzyme. PLANTA 2021; 254:43. [PMID: 34355288 PMCID: PMC8342391 DOI: 10.1007/s00425-021-03692-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/28/2021] [Indexed: 06/13/2023]
Abstract
MAIN CONCLUSION A synthetic peptide from the C-terminal end of C4-phosphoenolpyruvate carboxylase is implicated in the proteolysis of the enzyme, and Glc-6P or phosphorylation of the enzyme modulate this effect. Phosphoenolpyruvate carboxylase (PEPC) is a cytosolic, homotetrameric enzyme that performs a variety of functions in plants. Among them, it is primarily responsible for CO2 fixation in the C4 photosynthesis pathway (C4-PEPC). Here we show that proteolysis of C4-PEPC by cathepsin proteases present in a semi-purified PEPC fraction was enhanced by the presence of a synthetic peptide containing the last 19 amino acids from the C-terminal end of the PEPC subunit (pC19). Threonine (Thr)944 and Thr948 in the peptide are important requirements for the pC19 effect. C4-PEPC proteolysis in the presence of pC19 was prevented by the PEPC allosteric effector glucose 6-phosphate (Glc-6P) and by phosphorylation of the enzyme. The role of these elements in the regulation of PEPC proteolysis is discussed in relation to the physiological context.
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Affiliation(s)
- Jacinto Gandullo
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012, Seville, Spain
| | - Rosario Álvarez
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012, Seville, Spain
| | - Ana-Belén Feria
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012, Seville, Spain
| | - José-Antonio Monreal
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012, Seville, Spain
| | - Isabel Díaz
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Campus de Montegancedo, Autovía M40 (km 38), Pozuelo de Alarcón, 28034, Madrid, Spain
| | - Jean Vidal
- Institut de Biotechnologie des Plantes, UMR8618, Bâtiment 630, Université de Paris-Sud 11, 91405, Orsay, Cedex, France
| | - Cristina Echevarría
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012, Seville, Spain.
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Khan MIR, Khan NA, Jahan B, Goyal V, Hamid J, Khan S, Iqbal N, Alamri S, Siddiqui MH. Phosphorus supplementation modulates nitric oxide biosynthesis and stabilizes the defence system to improve arsenic stress tolerance in mustard. PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23 Suppl 1:152-161. [PMID: 33176068 DOI: 10.1111/plb.13211] [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: 10/03/2020] [Accepted: 11/01/2020] [Indexed: 05/21/2023]
Abstract
The interaction of mineral nutrients with metals/metalloids and signalling molecules is well known. In the present study, we investigated the effect of phosphorus (P) in mitigation of arsenic (As) stress in mustard (Brassica juncea L.). The study was conducted to investigate potential of 30 mg P·kg-1 soil P supplement (diammonium phosphate) to cope up with the adverse effects of As stress (24 mg As·kg-1 soil) in mustard plants Supplementation of P influenced nitric oxide (NO) generation, which up-regulated proline metabolism, ascorbate-glutathione system and glyoxalase system and alleviated the effects of on photosynthesis and growth. Arsenic stress generated ROS and methylglyoxal content was scavenged through P-mediated NO, and reduced As translocation from roots to leaves. The involvement of NO under P-mediated alleviation of As stress was substantiated with the use of cPTIO (NO biosynthesis inhibitor) and SNP (NO inducer). The reversal of P effects on photosynthesis under As stress with the use of cPTIO emphasized the role of P-mediated NO in mitigation of As stress and protection of photosynthesis The results suggested that P reversed As-induced oxidative stress by modulation of NO formation, which regulated antioxidant machinery. Thus, P-induced regulatory interaction between NO and reversal of As-induced oxidative stress for the protection of photosynthesis may be suggested for sustainable crops.
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Affiliation(s)
- M I R Khan
- Department of Botany, Jamia Hamdard, New Delhi, India
| | - N A Khan
- Department of Botany, Aligarh Muslim University, Aligarh, India
| | - B Jahan
- Department of Botany, Aligarh Muslim University, Aligarh, India
| | - V Goyal
- Department of Botany, Jamia Hamdard, New Delhi, India
| | - J Hamid
- Department of Botany, Jamia Hamdard, New Delhi, India
| | - S Khan
- Department of Botany, Jamia Hamdard, New Delhi, India
| | - N Iqbal
- Department of Botany, Jamia Hamdard, New Delhi, India
| | - S Alamri
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - M H Siddiqui
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
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Yang Z, Li JL, Liu LN, Xie Q, Sui N. Photosynthetic Regulation Under Salt Stress and Salt-Tolerance Mechanism of Sweet Sorghum. FRONTIERS IN PLANT SCIENCE 2020; 10:1722. [PMID: 32010174 PMCID: PMC6974683 DOI: 10.3389/fpls.2019.01722] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 12/09/2019] [Indexed: 05/18/2023]
Abstract
Sweet sorghum is a C4 crop with the characteristic of fast-growth and high-yields. It is a good source for food, feed, fiber, and fuel. On saline land, sweet sorghum can not only survive, but increase its sugar content. Therefore, it is regarded as a potential source for identifying salt-related genes. Here, we review the physiological and biochemical responses of sweet sorghum to salt stress, such as photosynthesis, sucrose synthesis, hormonal regulation, and ion homeostasis, as well as their potential salt-resistance mechanisms. The major advantages of salt-tolerant sweet sorghum include: 1) improving the Na+ exclusion ability to maintain ion homeostasis in roots under salt-stress conditions, which ensures a relatively low Na+ concentration in shoots; 2) maintaining a high sugar content in shoots under salt-stress conditions, by protecting the structures of photosystems, enhancing photosynthetic performance and sucrose synthetase activity, as well as inhibiting sucrose degradation. To study the regulatory mechanism of such genes will provide opportunities for increasing the salt tolerance of sweet sorghum by breeding and genetic engineering.
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Affiliation(s)
- Zhen Yang
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, China
- Shandong Provincial Key Laboratory of Microbial Engineering, School of Biological Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Jin-Lu Li
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Qi Xie
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, China University of Chinese Academy of Sciences, Beijing, China
| | - Na Sui
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, China
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Baena G, Feria AB, Echevarría C, Monreal JA, García-Mauriño S. Salinity promotes opposite patterns of carbonylation and nitrosylation of C 4 phosphoenolpyruvate carboxylase in sorghum leaves. PLANTA 2017; 246:1203-1214. [PMID: 28828537 DOI: 10.1007/s00425-017-2764-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 08/17/2017] [Indexed: 06/07/2023]
Abstract
Carbonylation inactivates sorghum C 4 PEPCase while nitrosylation has little impact on its activity but holds back carbonylation. This interplay could be important to preserve photosynthetic C4 PEPCase activity in salinity. Previous work had shown that nitric acid (NO) increased phosphoenolpyruvate carboxylase kinase (PEPCase-k) activity, promoting the phosphorylation of phosphoenolpyruvate carboxylase (PEPCase) in sorghum leaves (Monreal et al. in Planta 238:859-869, 2013b). The present work investigates the effect of NO on C4 PEPCase in sorghum leaves and its interplay with carbonylation, an oxidative modification frequently observed under salt stress. The PEPCase of sorghum leaves could be carbonylated in vitro and in vivo, and this post-translational modification (PTM) was accompanied by a loss of its activity. Similarly, PEPCase could be S-nitrosylated in vitro and in vivo, and this PTM had little impact on its activity. The S-nitrosylated PEPCase showed increased resistance towards subsequent carbonylation, both in vitro and in vivo. Under salt shock, carbonylation of PEPCase increased in parallel with decreased S-nitrosylation of the enzyme. Subsequent increase of S-nitrosylation was accompanied by decreased carbonylation. Taken together, the results suggest that S-nitrosylation could contribute to maintain C4 PEPCase activity in stressed sorghum plants. Thus, salt-induced NO synthesis would be protecting photosynthetic PEPCase activity from oxidative inactivation while promoting its phosphorylation, which will guarantee its optimal functioning in suboptimal conditions.
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Affiliation(s)
- Guillermo Baena
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012, Seville, Spain
| | - Ana B Feria
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012, Seville, Spain
| | - Cristina Echevarría
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012, Seville, Spain
| | - José A Monreal
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012, Seville, Spain
| | - Sofía García-Mauriño
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012, Seville, Spain.
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Wang X, Xu C, Cai X, Wang Q, Dai S. Heat-Responsive Photosynthetic and Signaling Pathways in Plants: Insight from Proteomics. Int J Mol Sci 2017; 18:E2191. [PMID: 29053587 PMCID: PMC5666872 DOI: 10.3390/ijms18102191] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/13/2017] [Accepted: 10/16/2017] [Indexed: 02/04/2023] Open
Abstract
Heat stress is a major abiotic stress posing a serious threat to plants. Heat-responsive mechanisms in plants are complicated and fine-tuned. Heat signaling transduction and photosynthesis are highly sensitive. Therefore, a thorough understanding of the molecular mechanism in heat stressed-signaling transduction and photosynthesis is necessary to protect crop yield. Current high-throughput proteomics investigations provide more useful information for underlying heat-responsive signaling pathways and photosynthesis modulation in plants. Several signaling components, such as guanosine triphosphate (GTP)-binding protein, nucleoside diphosphate kinase, annexin, and brassinosteroid-insensitive I-kinase domain interacting protein 114, were proposed to be important in heat signaling transduction. Moreover, diverse protein patterns of photosynthetic proteins imply that the modulations of stomatal CO₂ exchange, photosystem II, Calvin cycle, ATP synthesis, and chlorophyll biosynthesis are crucial for plant heat tolerance.
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Affiliation(s)
- Xiaoli Wang
- Shanghai Engineering Research Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China.
| | - Chenxi Xu
- Shanghai Engineering Research Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China.
| | - Xiaofeng Cai
- Shanghai Engineering Research Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China.
| | - Quanhua Wang
- Shanghai Engineering Research Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China.
| | - Shaojun Dai
- Shanghai Engineering Research Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China.
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Aloor BP, Avasthi UK, Raghavendra AS. Stimulation by abscisic acid of the activity of phosphoenolpyruvate carboxylase in leaf disks of Amaranthus hypochondriacus L., C 4 plant: role of pH and protein levels. PROTOPLASMA 2017; 254:1973-1981. [PMID: 28251362 DOI: 10.1007/s00709-017-1091-2] [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: 10/03/2016] [Accepted: 02/16/2017] [Indexed: 06/06/2023]
Abstract
C4 plants can more efficiently fix carbon in drought, high temperatures, and limitations of nitrogen or CO2. Primary carboxylation is mediated by phosphoenolpyruvate carboxylase (PEPC, 4.1.1.31) in mesophyll cytosol of C4 plants. Studies on hormonal regulation of C4 PEPC have been quite limited. We have examined the activity/regulation of PEPC by abscisic acid (ABA), a plant hormone, in the leaves of Amaranthus hypochondriacus. PEPC activity was enhanced upon 1-h incubation with 20 μM ABA by about 30% in dark and more than 2-fold in light. Glucose-6-phosphate activation of PEPC was enhanced, and sensitivity to L-malate was decreased after ABA treatment. Butyric acid (a weak acid) decreased PEPC activity and restricted the stimulation by ABA. In contrast, methylamine (an alkalinizing agent) increased the PEPC activity and enhanced the effect of ABA. ABA increased the levels of PEPC protein as well as its mRNA. Butyric acid/methylamine modulated the changes induced by ABA of PEPC protein and mRNA levels, indicating that acidification/alkalinization of leaf disks was very important. Our results emphasize the marked modulation of PEPC in C4 plants, by ABA. Such modulation by ABA could be significant when C4 plants are under water stress, when ABA is known to accumulate. When present, cycloheximide decreased the PEPC protein levels and restricted the extent of activation by ABA. We conclude that the enhancement by ABA of PEPC activity depends on cellular alkalinization as well as elevated PEPC protein levels.
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Affiliation(s)
- Bindu Prasuna Aloor
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Uday Kiran Avasthi
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
- Department of Genetics, Osmania University, Hyderabad, 500007, India
| | - Agepati S Raghavendra
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India.
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Arias-Baldrich C, de la Osa C, Bosch N, Ruiz-Ballesta I, Monreal JA, García-Mauriño S. Enzymatic activity, gene expression and posttranslational modifications of photosynthetic and non-photosynthetic phosphoenolpyruvate carboxylase in ammonium-stressed sorghum plants. JOURNAL OF PLANT PHYSIOLOGY 2017; 214:39-47. [PMID: 28431276 DOI: 10.1016/j.jplph.2017.03.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 03/27/2017] [Accepted: 03/28/2017] [Indexed: 05/24/2023]
Abstract
Sorghum plants grown with 5mM (NH4)2SO4 showed symptoms of stress, such as reduced growth and photosynthesis, leaf chlorosis, and reddish roots. Phosphoenolpyruvate carboxylase (PEPC) activity, by supplying carbon skeletons for ammonium assimilation, plays a pivotal role in tolerance to ammonium stress. This work investigated the effect of ammonium nutrition on PPC and PPCK gene expression, on PEPC activity, and on post-translational modifications (PTMs) of PEPC in leaves and roots of sorghum plants. Ammonium increased PEPC kinase (PEPCk) activity and the phosphorylation state of PEPC in leaves, both in light and in the dark, due to increased PPCK1 expression in leaves. This result resembled the effect of salinity on sorghum leaf PEPC and PEPCk, which is thought to allow a better functioning of PEPC in conditions that limit the income of reduced C. In roots, ammonium increased PEPC activity and the amount of monoubiquitinated PEPC. The first effect was related to increased PPC3 expression in roots. These results highlight the relevance of this specific isoenzyme (PPC3) in sorghum responses to ammonium stress. Although the role of monoubiquitination is not fully understood, it also increased in germinating seeds along with massive mobilization of reserves, a process in which the anaplerotic function of PEPC is of major importance.
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Affiliation(s)
- Cirenia Arias-Baldrich
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes n° 6, 41012 Seville, Spain.
| | - Clara de la Osa
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes n° 6, 41012 Seville, Spain.
| | - Nadja Bosch
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes n° 6, 41012 Seville, Spain; Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG), Campus UAB Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain.
| | - Isabel Ruiz-Ballesta
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes n° 6, 41012 Seville, Spain.
| | - José A Monreal
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes n° 6, 41012 Seville, Spain.
| | - Sofía García-Mauriño
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes n° 6, 41012 Seville, Spain.
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10
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Feria AB, Bosch N, Sánchez A, Nieto-Ingelmo AI, de la Osa C, Echevarría C, García-Mauriño S, Monreal JA. Phosphoenolpyruvate carboxylase (PEPC) and PEPC-kinase (PEPC-k) isoenzymes in Arabidopsis thaliana: role in control and abiotic stress conditions. PLANTA 2016; 244:901-13. [PMID: 27306451 DOI: 10.1007/s00425-016-2556-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 06/09/2016] [Indexed: 05/11/2023]
Abstract
Arabidopsis ppc3 mutant has a growth-arrest phenotype and is affected in phosphate- and salt-stress responses, showing that this protein is crucial under control or stress conditions. Phosphoenolpyruvate carboxylase (PEPC) and its dedicated kinase (PEPC-k) are ubiquitous plant proteins implicated in many physiological processes. This work investigates specific roles for the three plant-type PEPC (PTPC) and the two PEPC-k isoenzymes in Arabidopsis thaliana. The lack of any of the PEPC isoenzymes reduced growth parameters under optimal growth conditions. PEPC activity was decreased in shoots and roots of ppc2 and ppc3 mutants, respectively. Phosphate starvation increased the expression of all PTPC and PPCK genes in shoots, but only PPC3 and PPCK2 in roots. The absence of any of these two proteins was not compensated by other isoforms in roots. The effect of salt stress on PTPC and PPCK expression was modest in shoots, but PPC3 was markedly increased in roots. Interestingly, both stresses decreased root growth in each of the mutants except for ppc3. This mutant had a stressed phenotype in control conditions (reduced root growth and high level of stress molecular markers), but was unaffected in their response to high salinity. Salt stress increased PEPC activity, its phosphorylation state, and L-malate content in roots, all these responses were abolished in the ppc3 mutant. Our results highlight the importance of the PPC3 isoenzyme for the normal development of plants and for root responses to stress.
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Affiliation(s)
- Ana B Feria
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes no. 6, 41012, Seville, Spain
| | - Nadja Bosch
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes no. 6, 41012, Seville, Spain
| | - Alfonso Sánchez
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes no. 6, 41012, Seville, Spain
| | - Ana I Nieto-Ingelmo
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes no. 6, 41012, Seville, Spain
| | - Clara de la Osa
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes no. 6, 41012, Seville, Spain
| | - Cristina Echevarría
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes no. 6, 41012, Seville, Spain
| | - Sofía García-Mauriño
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes no. 6, 41012, Seville, Spain
| | - Jose Antonio Monreal
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes no. 6, 41012, Seville, Spain.
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Monreal JA, Arias-Baldrich C, Tossi V, Feria AB, Rubio-Casal A, García-Mata C, Lamattina L, García-Mauriño S. Nitric oxide regulation of leaf phosphoenolpyruvate carboxylase-kinase activity: implication in sorghum responses to salinity. PLANTA 2013; 238:859-69. [PMID: 23913013 DOI: 10.1007/s00425-013-1933-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 07/17/2013] [Indexed: 05/05/2023]
Abstract
Nitric oxide (NO) is a signaling molecule that mediates many plant responses to biotic and abiotic stresses, including salt stress. Interestingly, salinity increases NO production selectively in mesophyll cells of sorghum leaves, where photosynthetic C₄ phosphoenolpyruvate carboxylase (C₄ PEPCase) is located. PEPCase is regulated by a phosphoenolpyruvate carboxylase-kinase (PEPCase-k), which levels are greatly enhanced by salinity in sorghum. This work investigated whether NO is involved in this effect. NO donors (SNP, SNAP), the inhibitor of NO synthesis NNA, and the NO scavenger cPTIO were used for long- and short-term treatments. Long-term treatments had multifaceted consequences on both PPCK gene expression and PEPCase-k activity, and they also decreased photosynthetic gas-exchange parameters and plant growth. Nonetheless, it could be observed that SNP increased PEPCase-k activity, resembling salinity effect. Short-term treatments with NO donors, which did not change photosynthetic gas-exchange parameters and PPCK gene expression, increased PEPCase-k activity both in illuminated leaves and in leaves kept at dark. At least in part, these effects were independent on protein synthesis. PEPCase-k activity was not decreased by short-term treatment with cycloheximide in NaCl-treated plants; on the contrary, it was decreased by cPTIO. In summary, NO donors mimicked salt effect on PEPCase-k activity, and scavenging of NO abolished it. Collectively, these results indicate that NO is involved in the complex control of PEPCase-k activity, and it may mediate some of the plant responses to salinity.
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Affiliation(s)
- José A Monreal
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes nº 6, 41012, Seville, Spain
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Monreal JA, Arias-Baldrich C, Pérez-Montaño F, Gandullo J, Echevarría C, García-Mauriño S. Factors involved in the rise of phosphoenolpyruvate carboxylase-kinase activity caused by salinity in sorghum leaves. PLANTA 2013; 237:1401-13. [PMID: 23408154 DOI: 10.1007/s00425-013-1855-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 02/01/2013] [Indexed: 05/25/2023]
Abstract
Salinity increases phosphoenolpyruvate carboxylase kinase (PEPCase-k) activity in sorghum leaves. This work has been focused on the mechanisms responsible for this phenomenon. The light-triggered expression of SbPPCK1 gene, accountable for the photosynthetic C4-PEPCase-k, is controlled by a complex signal transduction chain involving phospholipases C and D (PLC and PLD). These two phospholipase-derived signalling pathways were functional in salinized plants. Pharmacological agents that act on PLC (U-73122, neomycin) or PLD (n-butanol) derived signals, blocked the expression of SbPPCK1, but had little effect on PEPCase-k activity. This discrepancy was further noticed when SbPPCK1-3 gene expression and PEPCase-k activity were studied in parallel. At 172 mM, the main effect of NaCl was to decrease the rate of PEPCase-k protein turnover. Meanwhile, 258 mM NaCl significantly increased both SbPPCK1 and SbPPCK2 gene expression and/or mRNA stability. The combination of these factors contributed to maintain a high PEPCase-k activity in salinity. LiCl increased calcium-dependent protein kinase (CDPK) activity in illuminated sorghum leaves while it decreased the rate of PEPCase-k degradation. The latter effect was restrained by W7, an inhibitor of CDPK activity. Recombinant PEPCase-k protein was phosphorylated in vitro by PKA. A conserved phosphorylation motif, which can be recognized by PKA and by plant CDPKs, is present in the three PEPCase-ks proteins. Thus, it is possible that a phosphorylation event could be controlling (increasing) the stability of PEPCase-k in salinity. These results propose a new mechanism of regulation of PEPCase-k levels, and highlight the relevance of the preservation of key metabolic elements during the bulk degradation of proteins, which is commonly associated to stress.
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Affiliation(s)
- José A Monreal
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes no 6, 41012, Seville, Spain
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Monreal JA, López-Baena FJ, Vidal J, Echevarría C, García-Mauriño S. Involvement of phospholipase D and phosphatidic acid in the light-dependent up-regulation of sorghum leaf phosphoenolpyruvate carboxylase-kinase. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:2819-27. [PMID: 20410319 PMCID: PMC2882271 DOI: 10.1093/jxb/erq114] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 04/05/2010] [Accepted: 04/06/2010] [Indexed: 05/21/2023]
Abstract
The photosynthetic phosphoenolpyruvate carboxylase (C(4)-PEPC) is regulated by phosphorylation by a phosphoenolpyruvate carboxylase kinase (PEPC-k). In Digitaria sanguinalis mesophyll protoplasts, this light-mediated transduction cascade principally requires a phosphoinositide-specific phospholipase C (PI-PLC) and a Ca(2+)-dependent step. The present study investigates the cascade components at the higher integrated level of Sorghum bicolor leaf discs and leaves. PEPC-k up-regulation required light and photosynthetic electron transport. However, the PI-PLC inhibitor U-73122 and inhibitors of calcium release from intracellular stores only partially blocked this process. Analysis of [(32)P]phosphate-labelled phospholipids showed a light-dependent increase in phospholipase D (PLD) activity. Treatment of leaf discs with n-butanol, which decreases the formation of phosphatidic acid (PA) by PLD, led to the partial inhibition of the C(4)-PEPC phosphorylation, suggesting the participation of PLD/PA in the signalling cascade. PPCK1 gene expression was strictly light-dependent. Addition of neomycin or n-butanol decreased, and a combination of both inhibitors markedly reduced PPCK1 expression and the concomitant rise in PEPC-k activity. The calcium/calmodulin antagonist W7 blocked the light-dependent up-regulation of PEPC-k, pointing to a Ca(2+)-dependent protein kinase (CDPK) integrating both second messengers, calcium and PA, which were shown to increase the activity of sorghum CDPK.
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Affiliation(s)
- José Antonio Monreal
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes no. 6, 41012 Seville, Spain
| | - Francisco Javier López-Baena
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes no. 6, 41012 Seville, Spain
| | - Jean Vidal
- Institut de Biotechnologie des Plantes, UMR CNRS 8618, Bâtiment 630, Université de Paris-Sud, Centre d′Orsay, Cedex, France
| | - Cristina Echevarría
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes no. 6, 41012 Seville, Spain
| | - Sofía García-Mauriño
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes no. 6, 41012 Seville, Spain
- To whom correspondence should be addressed: E-mail:
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Feria AB, Alvarez R, Cochereau L, Vidal J, García-Mauriño S, Echevarría C. Regulation of phosphoenolpyruvate carboxylase phosphorylation by metabolites and abscisic acid during the development and germination of barley seeds. PLANT PHYSIOLOGY 2008; 148:761-74. [PMID: 18753284 PMCID: PMC2556803 DOI: 10.1104/pp.108.124982] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Accepted: 08/14/2008] [Indexed: 05/20/2023]
Abstract
During barley (Hordeum vulgare) seed development, phosphoenolpyruvate carboxylase (PEPC) activity increased and PEPC-specific antibodies revealed housekeeping (103-kD) and inducible (108-kD) subunits. Bacterial-type PEPC fragments were immunologically detected in denatured protein extracts from dry and imbibed conditions; however, on nondenaturing gels, the activity of the recently reported octameric PEPC (in castor [Ricinus communis] oil seeds) was not detected. The phosphorylation state of the PEPC, as judged by l-malate 50% inhibition of initial activity values, phosphoprotein chromatography, and immunodetection of the phosphorylated N terminus, was found to be high between 8 and 18 d postanthesis (DPA) and during imbibition. In contrast, the enzyme appeared to be in a low phosphorylation state from 20 DPA up to dry seed. The time course of 32/36-kD, Ca(2+)-independent PEPC kinase activity exhibited a substantial increase after 30 DPA that did not coincide with the PEPC phosphorylation profile. This kinase was found to be inhibited by l-malate and not by putative protein inhibitors, and the PEPC phosphorylation status correlated with high glucose-6-phosphate to malate ratios, thereby suggesting an in vivo metabolic control of the kinase. PEPC phosphorylation was also regulated by photosynthate supply at 11 DPA. In addition, when fed exogenously to imbibing seeds, abscisic acid significantly increased PEPC kinase activity. This was further enhanced by the cytosolic protein synthesis inhibitor cycloheximide but blocked by protease inhibitors, thereby suggesting that the phytohormone acts on the stability of the kinase. We propose that a similar abscisic acid-dependent effect may contribute to produce the increase in PEPC kinase activity during desiccation stages.
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Affiliation(s)
- Ana-Belén Feria
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Seville, Spain
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