The Ti Plasmid of Agrobacterium tumefaciens Harbors an attM -Paralogous Gene, aiiB , Also Encoding N -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.