Regulation of pepc gene expression in Anabaena sp. PCC 7120 and its effects on cyclic electron flow around photosystem I and tolerances to environmental stresses

• Published in: Journal of integrative plant biology Vol. 57; no. 5; pp. 468 - 476
• Main Authors: Jia, Xiao‐Hui, Zhang, Peng‐Peng, Shi, Ding‐Ji, Mi, Hua‐Ling, Zhu, Jia‐Cheng, Huang, Xi‐Wen, He, Pei‐Min
• Format: Journal Article
• Language: English
• Published: China (Republic : 1949- ) Blackwell Pub 01.05.2015; Blackwell Publishing Ltd; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai 0cean University, Ministry of Education Shanghai, Shanghai 201306, China%Department of Biological Sciences, Louisiana State University, LA 70803, USA%National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, Shanghai 200032, China
• Subjects: absorbance; Adaptation, Physiological - genetics; Anabaena; Anabaena - genetics; Anabaena sp. PCC 7120; Cell Respiration; cyclic electron flow; Darkness; Down-Regulation - genetics; Electron Transport; Environment; gene expression; gene expression regulation; Gene Expression Regulation, Bacterial; genes; Genes, Bacterial; Genetic Vectors; Hydrogen-Ion Concentration; mutants; Mutation - genetics; pepc gene; PEPC基因; phosphoenolpyruvate carboxylase; Photosynthesis; photosystem I; Photosystem I Protein Complex - metabolism; Photosystem II Protein Complex - metabolism; quantitative polymerase chain reaction; Quantum Theory; reverse transcriptase polymerase chain reaction; Salinity; Stress, Physiological - genetics; Temperature; tolerance; Up-Regulation - genetics; Western blotting; Western印迹; 光系统I; 基因表达; 环境胁迫; 电子流; 调控; 鱼腥藻; pepc gene; Anabaena sp. PCC 7120; photosynthesis; tolerance; cyclic electron flow
• ISSN: 1672-9072; 1744-7909
• DOI: 10.1111/jipb.12241

Since pepc gene encoding phosphoenolpyruvate carboxylase （PEPCase） has been cloned from Anabaena sp. PCC 7120 and other cyanobacteria, the effects of pepc gene expression on photosynthesis have not been reported yet. In this study, we constructed mutants containing either upregu-lated （forward） or downregulated （reverse） pepc gene in Anabaena sp. PCC 7120. Results from real‐time quantitative polymerase chain reaction （RT‐qPCR）, Western blot and enzymatic analysis showed that PEPCase activity was signifi-cantly reduced in the reverse mutant compared with the wild type, and that of the forward mutant was obviously increased. Interestingly, the net photosynthesis in both the reverse mutant and the forward mutant were higher than that of the wild type, but dark respiration was decreased only in the reverse mutant. The absorbance changes of P700 upon saturation pulse showed the photosystem I （PSI） activity was inhibited, as reflected by Y（I）, and Y（NA） was elevated, and＆amp;nbsp;dark reduction of P700t was stimulated, indicating enhanced cyclic electron flow （CEF） around PSI in the reverse mutant. Additional y, the reverse mutant photosynthesis was higher than that of the wild type in low temperature, low and high pH, and high salinity, and this implies increased tolerance in the reverse mutant through downregulated pepc gene.