A mini-plasmid, pNVR-1012 (approximately 2.7 kb), was constructed from the Pseudomonas viridiflava novel plasmid which encoded the ice-nucleation gene. This plasmid encoded an ampicillin resistance gene, and had the unique restriction sites of EcoRI, HindIII, PstI, SalI and SphI. pNVR-nahG was constructed by ligation of a 3.1-kb HindIII fragment containing the salicylate hydroxylase (nahG) gene from the NAH plasmid with HindIII-digested pNVR-1012. The nahG gene was expressed in both Escherichia coil and Pseudomonas aeruginosa harboring this recombinant plasmid.