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Durall C, Kukil K, Hawkes JA, Albergati A, Lindblad P, Lindberg P. Production of succinate by engineered strains of Synechocystis PCC 6803 overexpressing phosphoenolpyruvate carboxylase and a glyoxylate shunt. Microb Cell Fact 2021; 20:39. [PMID: 33557832 PMCID: PMC7871529 DOI: 10.1186/s12934-021-01529-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/25/2021] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Cyanobacteria are promising hosts for the production of various industrially important compounds such as succinate. This study focuses on introduction of the glyoxylate shunt, which is naturally present in only a few cyanobacteria, into Synechocystis PCC 6803. In order to test its impact on cell metabolism, engineered strains were evaluated for succinate accumulation under conditions of light, darkness and anoxic darkness. Each condition was complemented by treatments with 2-thenoyltrifluoroacetone, an inhibitor of succinate dehydrogenase enzyme, and acetate, both in nitrogen replete and deplete medium. RESULTS We were able to introduce genes encoding the glyoxylate shunt, aceA and aceB, encoding isocitrate lyase and malate synthase respectively, into a strain of Synechocystis PCC 6803 engineered to overexpress phosphoenolpyruvate carboxylase. Our results show that complete expression of the glyoxylate shunt results in higher extracellular succinate accumulation compared to the wild type control strain after incubation of cells in darkness and anoxic darkness in the presence of nitrate. Addition of the inhibitor 2-thenoyltrifluoroacetone increased succinate titers in all the conditions tested when nitrate was available. Addition of acetate in the presence of the inhibitor further increased the succinate accumulation, resulting in high levels when phosphoenolpyruvate carboxylase was overexpressed, compared to control strain. However, the highest succinate titer was obtained after dark incubation of an engineered strain with a partial glyoxylate shunt overexpressing isocitrate lyase in addition to phosphoenolpyruvate carboxylase, with only 2-thenoyltrifluoroacetone supplementation to the medium. CONCLUSIONS Heterologous expression of the glyoxylate shunt with its central link to the tricarboxylic acid cycle (TCA) for acetate assimilation provides insight on the coordination of the carbon metabolism in the cell. Phosphoenolpyruvate carboxylase plays an important role in directing carbon flux towards the TCA cycle.
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Affiliation(s)
- Claudia Durall
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Box 523, 751 20, Uppsala, Sweden
| | - Kateryna Kukil
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Box 523, 751 20, Uppsala, Sweden
| | - Jeffrey A Hawkes
- Analytical Chemistry, Department of Chemistry-BMC, Uppsala University, Box 599, 751 20, Uppsala, Sweden
| | - Alessia Albergati
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Box 523, 751 20, Uppsala, Sweden
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Box 523, 751 20, Uppsala, Sweden
| | - Pia Lindberg
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Box 523, 751 20, Uppsala, Sweden.
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Peng Z, Miao X. Monoglucosyldiacylglycerol participates in phosphate stress adaptation in Synechococcus sp. PCC 7942. Biochem Biophys Res Commun 2020; 522:662-668. [PMID: 31787233 DOI: 10.1016/j.bbrc.2019.11.143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 11/21/2019] [Indexed: 12/22/2022]
Abstract
Cyanobacterial monoglucosyldiacylglycerol (MGlcDG) not only serves as a precursor for monogalactosyldiacylglycerol (MGDG) synthesis, but also participates in stress acclimation. Two genes (mgdA and mgdE) related to MGDG synthesis of Synechococcus sp. PCC 7942 were identified. The mgdE-suppressed mutant (AE) accumulated MGlcDG (4.2%) and showed better growth and photosynthetic activities compared with WT and other mutants (mgdA/mgdE-overexpressed and mgdA-suppressed strains), which suggested that MGlcDG was involved in phosphate stress adaptation for Synechococcus sp. PCC 7942. A notable increase in contents of 18:1 fatty acid (FA) of MGDG (127%), DGDG (68%), and SQDG (105%) in AE were found under phosphate starvation. However, the expression of △9 desaturase (desC) was not higher in AE than that in WT during phosphate-starved period. These results suggested that MGlcDG might be involved in the process of FA desaturation, which contributed to membrane fluidity and cell basic metabolism for stress acclimation in cyanobacteria. In complementary experiments of E. coli, although the expression of mgdA and desC in the mgdA and desC coexpressed strain (OEAC) reduced by 22% and 35% compared with that of the strains only overexpressing mgdA (OEA) or desC (OEC), the content of unsaturated FA in OEAC was the highest. This further implied that the accumulation of MGlcDG could prompt FA desaturation in E. coli. Therefore, we propose that an overproduction of MGlcDG is responsible for FA desaturation and participates in phosphate stress adaptation in cyanobacteria.
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Affiliation(s)
- Zhou Peng
- State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China; Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University, Shanghai, 200240, China; Biomass Energy Research Center, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Xiaoling Miao
- State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China; Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University, Shanghai, 200240, China; Biomass Energy Research Center, Shanghai Jiao Tong University, Shanghai, 200240, China.
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Zhao Y, Guo A, Wang Y, Hua J. Evolution of PEPC gene family in Gossypium reveals functional diversification and GhPEPC genes responding to abiotic stresses. Gene 2019; 698:61-71. [PMID: 30825597 DOI: 10.1016/j.gene.2019.02.061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 02/10/2019] [Accepted: 02/23/2019] [Indexed: 12/24/2022]
Abstract
Phosphoenolpyruvate carboxylase (PEPC) family genes play important roles in regulating plant growth and abiotic stress response. Based on the sequenced Gossypium genomes, we performed comprehensive analysis of PEPC homolog genes in cotton, which six, six, eleven and ten PEPC genes were identified in Gossypium arboreum (A2), G. raimondii (D5), G. hirsutum (AD1) and G. barbadense (AD2), respectively. These genes were divided into six subgroups: PEPC-i, PEPC-ii, PEPC-iii, PEPC-iv, PEPC-v and PEPC-vi; PEPC genes in each subgroup displayed conserved gene structure and motifs. Segmental duplication and whole genome duplication (WGD) events yielded the expansion of PEPC genes. Expression assays showed that the duplicated PEPC genes displayed diverse expression patterns, indicating that they experienced functional divergence. Of which, genes in PEPC-iv subgroup played crucial role for substrate distribution in cottonseed. Cis-elements, putative miRNAs and expression analyses showed that GhPEPC homologs might respond to abiotic stresses, expression levels of GhPEPC1 and GhPEPC2/GhPEPC2D genes were larger induced than other GhPEPC genes under cold, heat, salt, and drought stresses, indicating the crucial roles in abiotic stresses response. Present study serves new information to decipher the evolution and function of PEPC genes in Gossypium.
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Affiliation(s)
- Yanpeng Zhao
- Laboratory of Cotton Genetics, Genomics and Breeding, Beijing Key Laboratory of Crop Genetic Improvement, Key Laboratory of Crop Heterosis and Utilization, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
| | - Anhui Guo
- Laboratory of Cotton Genetics, Genomics and Breeding, Beijing Key Laboratory of Crop Genetic Improvement, Key Laboratory of Crop Heterosis and Utilization, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
| | - Yumei Wang
- Research Institute of Cash Crops, Hubei Academy of Agricultural Sciences, Wuhan 430064, Hubei, China
| | - Jinping Hua
- Laboratory of Cotton Genetics, Genomics and Breeding, Beijing Key Laboratory of Crop Genetic Improvement, Key Laboratory of Crop Heterosis and Utilization, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
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Qian X, Zhang Y, Lun DS, Dismukes GC. Rerouting of Metabolism into Desired Cellular Products by Nutrient Stress: Fluxes Reveal the Selected Pathways in Cyanobacterial Photosynthesis. ACS Synth Biol 2018; 7:1465-1476. [PMID: 29617123 DOI: 10.1021/acssynbio.8b00116] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Boosting cellular growth rates while redirecting metabolism to make desired products are the preeminent goals of gene engineering of photoautotrophs, yet so far these goals have been hardly achieved owing to lack of understanding of the functional pathways and their choke points. Here we apply a 13C mass isotopic method (INST-MFA) to quantify instantaneous fluxes of metabolites during photoautotrophic growth. INST-MFA determines the globally most accurate set of absolute fluxes for each metabolite from a finite set of measured 13C-isotopomer fluxes by minimizing the sum of squared residuals between experimental and predicted mass isotopomers. We show that the widely observed shift in biomass composition in cyanobacteria, demonstrated here with Synechococcus sp. PCC 7002, favoring glycogen synthesis during nitrogen starvation is caused by (1) increased flux through a bottleneck step in gluconeogenesis (3PG → GAP/DHAP), and (2) flux overflow through a previously unrecognized hybrid gluconeogenesis-pentose phosphate (hGPP) pathway. Our data suggest the slower growth rate and biomass accumulation under N starvation is due to a reduced carbon fixation rate and a reduced flux of carbon into amino acid precursors. Additionally, 13C flux from α-ketoglutarate to succinate is demonstrated to occur via succinic semialdehyde, an alternative to the conventional TCA cycle, in Synechococcus 7002 under photoautotrophic conditions. We found that pyruvate and oxaloacetate are synthesized mainly by malate dehydrogenase with minimal flux into acetyl coenzyme-A via pyruvate dehydrogenase. Nutrient stress induces major shifts in fluxes into new pathways that deviate from historical metabolic pathways derived from model bacteria.
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Affiliation(s)
- Xiao Qian
- Waksman Institute, Rutgers University, New Brunswick, New Jersey 08854, United States
| | - Yuan Zhang
- Waksman Institute, Rutgers University, New Brunswick, New Jersey 08854, United States
| | - Desmond S. Lun
- Center for Computational and Integrative Biology, Rutgers University, Camden, New Jersey 08102, United States
- Department of Computer Science, Rutgers University, Camden, New Jersey 08102, United States
- Department of Plant Biology, Rutgers University, New Brunswick, New Jersey 08901, United States
| | - G. Charles Dismukes
- Waksman Institute, Rutgers University, New Brunswick, New Jersey 08854, United States
- Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
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Zhang C, Li X, He Y, Zhang J, Yan T, Liu X. Physiological investigation of C 4-phosphoenolpyruvate-carboxylase-introduced rice line shows that sucrose metabolism is involved in the improved drought tolerance. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 115:328-342. [PMID: 28415033 DOI: 10.1016/j.plaphy.2017.03.019] [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: 11/21/2016] [Revised: 03/22/2017] [Accepted: 03/27/2017] [Indexed: 06/07/2023]
Abstract
We compared the drought tolerance of wild-type (WT) and transgenic rice plants (PC) over-expressing the maize C4PEPC gene, which encodes phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) gene, and evaluated the roles of saccharide and sugar-related enzymes in the drought response. Pot-grown seedlings were subjected to real drought conditions outdoors, and the yield components were compared between PC and untransformed wild-type (WT) plants. The stable yield from PC plants was associated with higher net photosynthetic rate under the real drought treatment. The physiological characters of WT and PC seedlings under a simulated drought treatment (25% (w/v) polyethylene glycol-6000 for 3 h; PEG 6000 treatment) were analyzed in detail for the early response of drought. The relative water content was higher in PC than in WT, and PEPC activity and the C4-PEPC transcript level in PC were elevated under the simulated drought conditions. The endogenous saccharide responses also differed between PC and WT under simulated drought stress. The higher sugar decomposition rate in PC than in WT under drought analog stress was related to the increased activities of sucrose phosphate synthase, sucrose synthase, acid invertase, and neutral invertase, increased transcript levels of VIN1, CIN1, NIN1, SUT2, SUT4, and SUT5, and increased activities of superoxide dismutase and peroxidase in the leaves. The greater antioxidant defense capacity of PC and its relationship with saccharide metabolism was one of the reasons for the improved drought tolerance. In conclusion, PEPC effectively alleviated oxidative damage and enhanced the drought tolerance in rice plants, which were more related to the increase of the endogenous saccharide decomposition. These findings show that components of C4 photosynthesis can be used to increase the yield of rice under drought conditions.
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Affiliation(s)
- Chen Zhang
- Institute of Food and Crops, Jiangsu Academy of Agricultural Sciences Nanjing 210014, PR China; College of Life Science, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Xia Li
- Institute of Food and Crops, Jiangsu Academy of Agricultural Sciences Nanjing 210014, PR China; College of Life Science, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Yafei He
- Institute of Food and Crops, Jiangsu Academy of Agricultural Sciences Nanjing 210014, PR China
| | - Jinfei Zhang
- Institute of Food and Crops, Jiangsu Academy of Agricultural Sciences Nanjing 210014, PR China
| | - Ting Yan
- Institute of Food and Crops, Jiangsu Academy of Agricultural Sciences Nanjing 210014, PR China; College of Life Science, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Xiaolong Liu
- Institute of Food and Crops, Jiangsu Academy of Agricultural Sciences Nanjing 210014, PR China
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Gomaa M, Al-Haj L, Abed R. Metabolic engineering of Cyanobacteria and microalgae for enhanced production of biofuels and high-value products. J Appl Microbiol 2016; 121:919-31. [DOI: 10.1111/jam.13232] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 05/25/2016] [Accepted: 07/07/2016] [Indexed: 01/26/2023]
Affiliation(s)
- M.A. Gomaa
- Biology Department; College of Science; Sultan Qaboos University; Al Khoud Sultanate of Oman
| | - L. Al-Haj
- Biology Department; College of Science; Sultan Qaboos University; Al Khoud Sultanate of Oman
| | - R.M.M. Abed
- Biology Department; College of Science; Sultan Qaboos University; Al Khoud Sultanate of Oman
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Enhanced growth at low light intensity in the cyanobacterium Synechocystis PCC 6803 by overexpressing phosphoenolpyruvate carboxylase. ALGAL RES 2016. [DOI: 10.1016/j.algal.2016.03.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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