Expression and functional analysis of OsNAD-ME1 in Escherichia coli

OsNAD-ME1 is a member of rice NAD-dependent malic enzyme family. For testing its subcellular location, OsNAD-ME1-GFP fusion protein expression vector was constructed and transformed into yeast. It was found that the location of GFP was consistent with stained mitochondria in yeast cells, which proved that OsNAD-ME1 was located in mitochondria. The results of Northern analysis showed that the expression of OsNAD-ME1 was induced by different abiotic stresses. Then OsNAD-ME1 was introduced into E. coli BL21 using pGEX-6p-3 vector with GST tag. The growths of E. coli cells expressing GST-OsNAD-ME1 under 800mmol/L NaCl, 100 mmol/L NaHCO3, 10% PEG and 3 mmol/L H2O2, respectively, after IPTG inducement were determined and compared with the growths of E. coli cells expressing GST. The expression of GST-OsNAD-ME1 made the growth of cells increase than control, which indicated that OsNAD-ME1 enhanced tolerance to salt, alkali, drought, and oxidative treatments.