The Ti Plasmid of <i>Agrobacterium tumefaciens</i> Harbors an <i>attM</i> -Paralogous Gene, <i>aiiB</i> , Also Encoding <i>N</i> -Acyl Homoserine Lactonase Activity

Abstract

The Agrobacterium tumefaciens C58 genome contains three putative N-acyl homoserine lactone (acyl-HSL) hydrolases, which are closely related to the lactonase AiiA of Bacillus. When expressed in Escherichia coli, two of the putative acyl-HSL hydrolases, AttM and AiiB, conferred the ability to degrade acyl-HSLs on the host. In Erwinia strain 6276, the lactonases reduced the endogenous acyl-HSL level and the bacterial virulence in planta.