PROFERRIOXAMINE PROFILES OF ERWINIA-HERBICOLA AND RELATED BACTERIA

Two strains of Erwinia herbicola effective in the biocontrol of E. amy lovora, the etiological agent of fire blight, were screened for profer rioxamine siderophores by on-line liquid chromatoraphy-electrospray ma ss spectrometry (LC-MS). Type strains of E. herbicola and Pantoea spec ies were included in this study for taxonomic comparisons, Proferrioxa mine profiles similar to that previously described for E. amylovora, i ncluding tri- and tetrameric hydroxamates and diaminopropane-containin g proferrioxamines, were observed for P. agglomerans, but not for othe r E. herbicola-like species. Biocontrol activity was not correlated wi th proferrioxamine synthesis, The results of this study are consistent with the notion that some, but not all, biocontrol strains may inhibi t E. amylovora via competition for iron, Further studies into the link between biocontrol of fire blight and siderophores are thus warranted . This study also revealed limitations of standard nutrient utilizatio n and fatty acid profile analyses for the differentiation of P. agglom erans, P. dispersa and other E. herbicola-like species from each other , Given these limitations, LC-MS may become a much needed additional d iagnostic tool for the identification of E. herbicola-like strains at the species level.