Two variants of plant growth-promoting strain Pseudomonas putida BS1380 harboring the naphthalene degradative plasmid pBS2 and the recombinant plasmid pNAU64 that contains the genes encoding for naphthalene dioxygenase were constructed by conjugation. The ability of this strain to produce phytohormone indole-3-acetic acid from different carbon sources was studied. Indole-3-acetic acid synthesis by these transconjugants was 15-30 times as much in contrast to a wild-type strain with glucose as the sole carbon source. No difference was observed in other carbon or nitrogen sources. It is suggested that naphthalene dioxygenase is involved in the conversion of indole-3-pyruvic acid to indole-3-acetic acid.