Using Genomes and Evolutionary Analyses to Screen for Host-Specificity and Positive Selection in the Plant Pathogen Xylella fastidiosa
Tiffany N. Batarseh, Abraham Morales‐Cruz, Brian Ingel, M. Caroline Roper, Brandon S. Gaut
Abstract
Xylella fastidiosa causes devasting diseases to several critical crops. Because X. fastidiosa colonizes and infects many plant species, it is important to understand whether the genome of X. fastidiosa has genetic determinants that underlie specialization to specific host plants. We analyzed genome sequences of X. fastidiosa to investigate evolutionary relationships and to test for evidence of positive selection on specific genes. We found a significant signal between genome diversity and host plants, consistent with bacterial specialization to specific plant hosts. By screening for positive selection, we identified both core and accessory genes that may affect pathogenicity, including genes involved in biofilm formation.