Putative transcription antiterminator RfaH contributes to Erwinia amylovora virulence.

The gram-negative bacterium Erwinia amylovora causes fire blight disease of apple and pear trees. The exopolysaccharide amylovoran and lipopolysaccharides are essential E. amylovora virulence factors.

Virulence Genetics of an Erwinia amylovora Putative Polysaccharide Transporter Family Member.

The Gram-negative enterobacterium causes fire blight disease in apple and pear trees. Lipopolysaccharides and the exopolysaccharide amylovoran are essential virulence factors. We found that mutations in disrupted amylovoran production and virulence in apple fruits and tree shoots and that the deletion of suppressed the mutant phenotype.

Extragenic Suppression of Elongation Factor P Gene Mutant Phenotypes in Erwinia amylovora.

Elongation factor P (EF-P) facilitates the translation of certain peptide motifs, including those with multiple proline residues. EF-P must be posttranslationally modified for full functionality; in enterobacteria, this is accomplished by two enzymes, namely, EpmA and EpmB, which catalyze the β-lysylation of EF-P at a conserved lysine position. Mutations to or its modifying enzymes produce pleiotropic phenotypes, including decreases in virulence, swimming motility, and extracellular polysaccharide production, as well as proteomic perturbations.