The enterobacterium Erwinia amylovora is a devastating plant pathogen causing necrotrophic fire blight disease of apple, pear, and other rosaceous plants. In this study, we used a modified in vivo expression technology system to identify E. amylovora genes that are activated during infection of immature pear tissue, a process that requires the major pathogenicity factors of this organism. We id...

Blossoms are important sites of infection for Erwinia amylovora, the causal agent of fire blight of rosaceous plants. Before entering the tissue, the pathogen colonizes the stigmatic surface and has to compete for space and nutrient resources within the epiphytic community. Several epiphytes are capable of synthesizing antibiotics with which they antagonize phytopathogenic bacteria. Here, we re...

Mutants of Erwinia amylovora CFBP 1430 lacking a functional high-affinity iron transport system mediated by desferrioxamine are impaired in their ability to initiate fire blight symptoms (A. Dellagi, M.-N. Brisset, J.-P. Paulin, and D. Expert. Mol. Plant-Microbe Interact. 11:734-742, 1998). In this study, a chromosomal transcriptional lacZ fusion was used to analyze the expression in planta of ...

Harpins are proteins secreted by the type-three secretion system of phytopathogenic bacteria. They are known to induce a hypersensitive response (HR) in non-host plant leaf tissue. Erwinia amylovora, the fire blight pathogen of pear and apple trees, secretes two different harpins, HrpNea and HrpWea. In the present study, we showed that an Erwinia amylovora hrpWea mutant induces stronger electro...

Erwinia amylovora ferments glucose to yield mainly ethanol, lactate, and carbon dioxide (Sutton and Starr, 1959). The initial steps in the o.xidation of glucose by this bacterium were reported by Katznelson (1955), who later (Katznelson, 1958) showed the presence of certain key enzymes of the Embden-Meyerhof pathway in sonic extracts. The present study, briefly summarized elsewhere (Sutton and ...