Isolation and Gene Expression Investigation in Photosynthetic Isoform of Phosphoenolpyruvate Carboxylase Gene in Halophytic Grass Aeluropus Littoralis under Salinity Stress

C4 plants have very high photosynthetic efficiency under drought stress due to lower water usage and do not require the opening and closing of stomata. This advantage has been created by complementary mechanisms of primary carboxylation in leaves mesophilic cells. In species which are initial carboxylation of mesophilic CO2 during C4 photosynthesis and crassulacean acid metabolism done, the PEPc enzyme catalyses the irreversible reaction of phosphoenolpyruvate in the presence of bicarbonate ions to produce oxaloacetate. The aim of the present study was to partial isolation of pepc coding sequence from halophytic grass Aeluropus littoralis, studying codon bias pattern and also quantitative analysis of its expression in 0 (control) and 600 mM NaCl relative to beta actin gene expression as internal control using Real-time PCR. As a result, a 678 bp fragment of pepc gene coding sequence was isolated and registered in NCBI gene bank under KP122945 accession number. The isolated fragment showed highest homology (in protein level) with Eragrostis minor and Zoysia japonica species and its CAI index was estimated 0.82. Finally, the quantitative analysis of gene expression under 600 mM salt stress showed that the level of pepc gene transcription was increased about 3 times (compared to control) in response to stress.