Cloning and stress-responding expression analysis of malonyl CoA-acyl carrier protein transacylase gene of Nannochloropsis gaditana

Malonyl CoA-acyl carrier protein transacylase (MCAT, E2.3.1.39) is closely associated with the FASII pathway of fatty acid biosynthesis. However, the information about microalgal MCAT is scarce. In this study, a MCAT gene was isolated from Nannochloropsis gaditana with its deduced protein (NgMCAT) characterized with bioinformatic tools. The abundance of the NgMCAT transcript under different environmental conditions was determined with real-time quantitative PCR. Results showed that the open reading frame (ORF) of NgMCAT was 1059 bp in length, which encoded 352 amino acid residues. The abundance of NgMCAT transcript reached the maximum (5.17-fold) at 6 h when sodium nitrate was limited, and reached the maximum (4.25-fold) at 12 h at low temperature (15 °C). The abundance of NgMCAT transcript fluctuated at high temperature (35 °C) when the concentration of nitrate and sodium chloride exceeded 150 mg/L and 62 g/L, respectively. In addition, some components of fatty acid that changed with the expression of NgMCAT were also observed.