cumA multicopper oxidase genes from diverse Mn(II)-oxidizing and non-Mn(II)-oxidizing Pseudomonas strains

A multicopper oxidase gene, cumA, required for Mn(II) oxidation was recently identified in Pseudomonas putida strain GB-I. In the present study, degenerate primers based on the putative copper-binding regions of the cumA gene product were used to PCR amplify cum4 gene sequences from a variety of Pseudomonas strains, including both Mn(II)-oxidizing and non-Mn(II)-oxidizing strains. The presence of highly conserved cumA gene sequences in several apparently non-Mn(II)-oxidizing Pseudomonas strains suggests that this gene may not be expressed, may not be sufficient alone to confer the ability to oxidize Mn(II), or may have an alternative function in these organisms. Phylogenetic analysis of both CumA and 16S rRNA sequences revealed similar topologies between the respective trees, including the presence of several distinct phylogenetic clusters. Overall, our results indicate that both the cumA gene and the capacity to oxidize Mn(II) occur in phylogenetically diverse Pseudomonas strains.