Genomic insights of the most prevalent sequence type of Xanthomonas citri pv. punicae strain 118, causative agent of bacterial blight on pomegranate

Abstract The most destructive pathogen of pomegranate, Xanthomonas citri pv. punicae (Xcp) , causes bacterial blight or oily spots affecting quality and quantity of pomegranate production worldwide. Different Xcp isolates obtained from geographically distant regions exhibit remarkable similarities based on multi-locus sequence analysis (MLSA) and SSR marker-based analysis. These isolates can be grouped into just four sequence types (ST1-4) highlighting the clonal nature of the pathogen. In the current study, genome of one of the isolates of Xcp (Xcp-118) belonging to ST3 (which is more prevalent and virulent) was sequenced and annotated. The results offer genomic characterization of genes potentially associated with survival and virulence in this isolate. Further, phylogenetic analysis was carried out on 23 whole genome sequences of different species and pathovars of Xanthomonas. The results reemphasize on the genetic similarity exhibited by different pathovars of X. citri indicating towards the host-specific mechanism for induction of virulence genes as these pathovars are unable to cross-infect the host plant. Thus, in future, the complete genome sequence of Xcp-118 can be exploited to unveil novel insights into the organization of genes involved in pathogenesis of Xcp on pomegranate and may assist in developing suitable blight management practices.