Transmissible Plasmid Coding Early Enzymes of Naphthalene Oxidation in Pseudomonas putida

Abstract

The capacity of Pseudomonas putida PpG7 (ATCC 17,485) to grow on naphthalene, phenotype Nah⁺, is lost spontaneously, and the frequency is increased by treatment with mitomycin C. The Nah⁺ growth character can be transferred to cured or heterologous fluorescent pseudomonads lacking this capacity by conjugation, or between phage pf16-sensitive strains by transduction. After mutagenesis, strains can be selected with increased donor capacity in conjugation. Clones which use naphthalene grow on salicylate and carry catechol 2,3-oxygenase, the initial enzyme of the aromatic α-keto acid pathway, whereas cured strains grow neither on salicylate nor naphthalene and lack catechol 2,3-oxygenase, but retain catechol 1,2-oxygenase and the aromatic β-keto adipate pathway enzymes.