Genetic Basis of the Biodegradation of Salicylate in Pseudomonas

The genetic basis of the biodegradation of salicylate in Pseudomonas putida R1 has been studied. This strain utilizes the meta pathway for oxidizing salicylate through formation of catechol and 2-hydroxymuconic semialdehyde. The enzymes of the meta pathway are induced by salicylate but not by catechol, and the genes specifying these enzymes are clustered. The gene cluster can be eliminated from some salicylate-positive cells by treatment with mitomycin C and appears to exist inside the cell as an extrachromosomal element. This extrachromosomal gene cluster, termed the SAL plasmid, can be transferred by conjugation from P. putida R1 to a variety of other Pseudomonas species.