Transformation of biocontrol agent Enterobacter agglomerans with salicylate utilizing gene and its monitoring in orchard soil

A recombinant plasmid (named as pBS-NahG) containing the NahG gene which en codes the salicylate utilization, was constructed. The NahG gene was amplif ied by PCR from plasmid pNAH7 in Pseudomonas putida R20 and subcloned into pBluescript. Plasmid pBS-NahG was transformed into Enterobacter agglomerans , strain B8, an antagonist of Phytophthora cactorum which is a pathogen tha t causes crown and root rot of apple trees. This plasmid (pBS-NahG) did not affect growth or antagonism of E. agglomerans and was stable under both se lective and nonselective conditions in nutrient broth medium. This plasmid conferred to E. agglomerans B8 (B8NG) the ability to utilize salicylate in culture and in orchard soil. In soil treatment, the transformed strain B8NG was detected after 60 d in orchard soil treated with salicylic acid wherea s the non-transformed strain Bs of E. agglomerans was was not detected afte r 30 d.