Plasmid-encoded genes specifying aniline oxidation from Acinetobacter sp. strain YAA

Abstract

Acinetobacter sp. strain YAA is able to use aniline and o-toluidine as the sole carbon and energy source. This strain has several different plasmids and acridine orange curing suggested that aniline utilization in strain YAA was plasmid-encoded. The gene cluster involved in aniline oxidation was cloned in Escherichia coli JM109 from the total plasmid DNA of strain YAA. A recombinant E. coli containing an 18.5 kb insert fragment showed yellow colouration on aniline-containing plates, indicating the formation of 2-hydroxymuconic semialdehyde from aniline. In addition, subcloning of a 9.0 kb Sail fragment from the insert in E. coli resulted in the accumulation of catechol. Southern hybridization studies indicated that the aniline oxygenase gene (atdA) was present on one of the plasmids, pYA1. These results suggest that in strain YAA aniline is degraded via catechol through a pathway involving meta-cleavage of the benzene-ring by plasmid-encoded genes including atdA.