Xanthomonas citri pv. lagerstroemium, description of a new pathovar causing leaf spot on crape myrtle.

Abstract

Bacterial leaf spot caused by Xanthomonas was reported in 2014 as a new disease of crape myrtle. Unfortunately, this foundational strain was lost, preventing further experimentation, sequencing of the genome, and phylogenetic analysis. This work describes a collection of Xanthomonas strains isolated from angular leaf spot lesions on crape myrtle in North Carolina from 2014 to 2023. This study includes full reference genomes, as well as re-fulfillment of Koch's postulates. Genomes were obtained with hybrid whole genome sequencing using Illumina and Nanopore and assembled to develop robust genomic resources for these disease-causing strains. The completed genomes support inclusion of the strains in the X. citri species group; however, both phylogenetic analysis and the identification of a novel plant host suggest the creation of the new pathovar Xanthomonas citri pv. lagerstroemium.