萝卜抗真菌蛋白1（Rs-AFP1)在大肠杆菌中的融合表达及其对大丽轮枝菌抑制活性的研究

Fusion Expression of Raphanus sativus-Antifungal Protein 1 (Rs-AFP1) in Escherichia coli and Its Antifungal Activity on Verticillium dahliae

The Raphanus sativus L. antifungal protein 1 (Rs-AFP1) gene was isolated by polymerase chain reaction (PCR). The complete open reading frame and the fragment encoding the putative mature protein were inserted into the prokaryotic expression vector pET-32b(+), respectively. Subsequent expression showed that the Rs-AFP1 was produced in E. coli as a 27 kD fusion protein only when the N-terminal signal peptide was removed. After treatment with thrombin to remove part of the N-terminal His.tag sequence, the bacterially expressed Rs-AFP1 was used for fungal growth inhibition assay which was conducted on Verticillium dahliae Kleb., a soil-born fungus causing the cotton wilt disease. Results showed that, in the liquid medium, the Rs-AFP1 fusion protein at a concentration of 0.3 g/L clearly inhibited the growth of V. dahliae and the germination of spores. Thus the bacterially expressed fusion protein had the antifungal activity against V. dahliae.