Abstract：SdiA, belongs to luxR family involved in quorum sensing, is present in Escherichia coli and Salmonella typhimurium genome. A homolog of SdiA was cloned from Erwinia amylovora and named as EASdiA, which shares 45.42% amino acid identity with Es. coli and 43.33% with S. typhimurium. Based on regions of luxR-homolog in Er. amylovora where divergent from other luxR-homolog reported, specific primers F-EAluxR and R-EAluxR were designed to identify Er. amylovora. Ten tested Er. amylovora strains were successfully identified using these primers from a range of closely related bacteria. Less than 10 cells can be detected, when tested with extraction of pear tissue, as few as 102 bacteria can be detected. This is the first report of cloning EAsdiA from Er. amylovora and applied for molecular detection of this bacterium .
