An Erwinia amylovora yjeK mutant exhibits reduced virulence, increased chemical sensitivity and numerous environmentally dependent proteomic alterations

• Published in: Molecular plant pathology Vol. 19; no. 7; pp. 1667 - 1678
• Main Authors: Klee, Sara M., Mostafa, Islam, Chen, Sixue, Dufresne, Craig, Lehman, brian L., Sinn, Judith P., Peter, Kari A., McNellis, Timothy W.
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.07.2018; John Wiley and Sons Inc
• Subjects: Abundance; apple; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Blight; Dependence; E coli; Elongation; elongation factor P; Erwinia amylovora; Erwinia amylovora - genetics; Erwinia amylovora - pathogenicity; fire blight; iTRAQ; Lysine; Malus - microbiology; Mutants; Organic chemistry; Original; pathogenicity; Pears; Peptide Elongation Factors - genetics; Peptide Elongation Factors - metabolism; Phenotypes; Plant Diseases - microbiology; Polyproline; Polysaccharides; protein translation; Proteins; Proteomics; Proteomics - methods; Pyrus - microbiology; Salmonella; Sensitivity; Swimming; Translation; Virulence; Virulence - genetics; apple; pathogenicity; protein translation; iTRAQ; fire blight; Erwinia amylovora; elongation factor P
• ISSN: 1464-6722; 1364-3703
• DOI: 10.1111/mpp.12650

Summary The Gram‐negative bacterium Erwinia amylovora causes fire blight, an economically important disease of apples and pears. Elongation factor P (EF‐P) is a highly conserved protein that stimulates the formation of the first peptide bond of certain proteins and facilitates the translation of certain proteins, including those with polyproline motifs. YjeK and YjeA are two enzymes involved in the essential post‐translational β‐lysylation of EF‐P at a conserved lysine residue, K34. EF‐P, YjeA and YjeK have been shown to be essential for the full virulence of Escherichia coli, Salmonella species and Agrobacterium tumefaciens, with efp, yjeA and yjeK mutants having highly similar phenotypes. Here, we identified an E. amylovora yjeK::Tn5 transposon mutant with decreased virulence in apple fruit and trees. The yjeK::Tn5 mutant also showed pleiotropic phenotypes, including reduced growth in rich medium, lower extracellular polysaccharide production, reduced swimming motility and increased chemical sensitivity compared with the wild‐type, whilst maintaining wild‐type level growth in minimal medium. All yjeK::Tn5 mutant phenotypes were complemented in trans with a plasmid bearing a wild‐type copy of yjeK. Comprehensive, quantitative proteomics analyses revealed numerous, environmentally dependent changes in the prevalence of a wide range of proteins, in higher abundance and lower abundance, in yjeK::Tn5 compared with the wild‐type, and many of these alterations could be linked to yjeK::Tn5 mutant phenotypes. The environmental dependence of the yjeK::Tn5 mutant proteomic alterations suggests that YjeK could be required for aspects of the environmentally dependent regulation of protein translation. YjeK activity may be critical to overcoming stress, including the challenging host environment faced by invading pathogenic bacteria.