Organization and regulation of meta cleavage pathway genes for toluene ando-xylene derivative degradation in Pseudomonas stutzeri OX1

Pseudomonas stutzeri OX1 meta pathway genes for toluene and o-xylene catabo lism were analyzed, and loci encoding phenol hydroxylase, catechol 2,3-diox ygenase, 2-hydroxymuconate semialdehyde dehydrogenase, and 2-hydroxymuconat e semialdehyde hydrolase were mapped. Phenol hydroxylase converted a broad range of substrates, as it was also able to transform the nongrowth substra tes 2,4-dimethylphenol and 2,5-dimethgl-phenol into 3,5-dimethylcatechol an d 3,6-dimethylcatechol, respectively, which, however, were not cleaved by c atechol 2,3-dioxygenase, The identified gene cluster displayed a gene order similar to that of the Pseudomonas sp, strain CF600 dmp operon for phenol catabolism and was found to be coregulated by the tou operon activator TouR A hypothesis about the evolution of the toluene and o-xylene catabolic pat hway in P. stutzeri OX1 is discussed.