Three genes controlling streptomycin susceptibility inAgrobacterium fabrum

Abstract

Streptomycin is a commonly used antibiotic for its efficacy against diverse bacteria. The plant pathogenAgrobacterium fabrumis a model for studying pathogenesis and interkingdom gene transfer. Streptomycin-resistant variants ofA. fabrumare commonly employed in genetic analyses, yet mechanisms of resistance and susceptibility to streptomycin in this organism have not previously been investigated. We observe that resistance to a high concentration of streptomycin arises at high frequency inA. fabrumand we link this trait to the presence of a chromosomal gene (strB) encoding a putative aminoglycoside phosphotransferase. We show howstrB, along withrpsL(encoding ribosomal protein S12) andrsmG(encoding a 16S rRNA methyltransferase) modulate streptomycin sensitivity inA. fabrum.