MOLECULAR ANALYSIS OF GENES ENCODING PHENAZINE BIOSYNTHESIS IN THE BIOLOGICAL-CONTROL BACTERIUM PSEUDOMONAS-AUREOFACIENS-30-84

The DNA sequence of five contiguous open reading frames encoding enzym es for phenazine biosynthesis in the biological control bacterium Pseu domonas aureofaciens 30-84 was determined. These open reading frames w ere named phzF, phzA, phzB, phzC and phzD. Protein PhzF is similar to 3-deoxy-D-arabino-heptulosonate-7-phosphate synthases of solanaceous p lants, PhzA is similar to 2,3-dihydro-2,3-dihydroxybenzoate synthase ( EntB) of Escherichia coli. PhzB shares similarity with both subunits o f anthranilate synthase and the phzB open reading frame complemented a n E. coli trpE mutant deficient in anthranilate synthase activity, Alt hough phzC shares little similarity to known genes, its product is res ponsible for the conversion of phenazine-l-carboxylic acid to 2-hydrox y-phenazine-1-carboxylic acid. PhzD is similar to pyridoxamine phospha te oxidases. These results indicate that phenazine biosynthesis in P. aureofaciens shares similarities with the shikimic acid, enterochelin, and tryptophan biosynthetic pathways.