Large-Scale Intersubspecific Recombination in the Plant-Pathogenic Bacterium Xylella fastidiosa Is Associated with the Host Shift to Mulberry

• DOI: 10.1128/aem.04112-13
• Publication Date: 2014-03-08T05:40:12Z
• Authors: Leonard Nunney; Erin L. Schuenzel; Mark Scally; Robin E. Bromley; Richard Stouthamer
• Keywords: Xylella fastidiosa; Subspecies; Multiplex; Multilocus sequence typing

ABSTRACT Homologous recombination plays an important role in the structuring of genetic variation many bacteria; however, its importance adaptive evolution is not well established. We investigated association intersubspecific homologous (IHR) with shift to a novel host (mulberry) by plant-pathogenic bacterium Xylella fastidiosa . Mulberry leaf scorch was identified about 25 years ago native red mulberry eastern United States and has spread introduced white California. Comparing sequence 8 genes (4,706 bp) from 21 mulberry-type isolates published data (352 representing all subspecies), we confirmed previous indications that define group distinct 4 subspecies, propose naming taxon X. subsp. morus The ancestry gene sequences mixed, derived (introduced Central America), 3 multiplex (considered States), 1 chimeric, demonstrating this originated large-scale IHR. very low within-type (0.08% site polymorphism), plus apparent inability infect mulberry, suggests achieved after strong selection acted on variants created Sequence indicate single ancestral IHR event gave rise only but also recombinant which infects several hosts type naturally infecting blueberry, thus implicating invasion at least two hosts, blueberry.