Identification of some genes involved in pathogenicity of an Erwinia amylovora native strain by random mutagenesis method

Erwinia amylovora is a gram-negative bacterium that causes fire blight, an important disease in pome fruit trees. The aim of this study was to generate a transposon mutant library using mini-Tn5 lacZ1, in an Erwinia amylovora native isolate for identification of some virulence associated genes in this strain. Among 1500 mutated colonies, two colonies which indicated less virulence on immature pear fruits were selected for further analysis. The DNA sequencing results of the two selected mutants showed a transposon insertion in an araC family transcriptional regulator gene and an insertion in nonribosomal peptide synthetase (NRPS). This study demonstrated that the araC transcriptional regulator and the NRPS genes are required for full virulence of E. amylovora. More studies are necessary to identify the role of these genes in physiology and virulence of E. amylovora.