Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/20/2021
Publication Date: 8/2/2021
Citation: O'Leary, M.L., Burbank, L.P., Stenger, D.C. 2021. Differential epigenetic modifications among Xylella fastidiosa strains correlate with type I restriction-modification system variation. American Phytopathological Society Abstracts.
Technical Abstract: Xylella fastidiosa is a bacterial plant pathogen with genetically distinct subspecies which collectively cause disease in diverse host plants. Genomes of X. fastidiosa strains are enriched in genes encoding restriction-modification systems, which methylate native DNA and cut unmethylated DNA at specific sequence motifs. Restriction-modification systems can provide defense against phages and limit horizontal gene transfer between closely related strains, but can also influence expression of virulence-related genes in some animal-pathogenic bacteria. Type I restriction-modification systems function as a protein complex, with sequence specificity determined by the two target recognition domains of a specificity subunit, HsdS. Analysis of 117 X. fastidiosa strains reveals most strains contain three conserved type I restriction-modification systems, while strains of subspecies multiplex and pauca contain a fourth system. Up to twenty-two unique hsdS alleles were identified per system; in total, at least 30 aggregate hsdS allele profiles were identified across X. fastidiosa strains, suggesting differential genomic methylation patterns exist across strains. Genomic methylation profiles of twelve X. fastidiosa strains were determined and contain two to four methylated motifs characteristic of type I restriction-modification recognition sites. Variation among these motif sequences was identified both within and between X. fastidiosa subspecies and is consistent with variation among hsdS alleles.