Computational identification of putative copper-binding proteins in pomegranate bacterial blight pathogen Xanthomonas citri pv. punicae

Xanthomonas citri pv. punicae (Xcp) causes bacterial blight in pomegranate, and an effective management strategy to control this devastating disease is yet to be formulated. Copper is a vital micronutrient that plays a significant role in bacterial physiology and virulence mechanism. It acts as a cofactor and conjugates with proteins, catalyse various biological processes, and contributes to the structural integrity of proteins. In this study, we have screened copper-binding proteins of Xcp and their plausible role in the pathogenesis of pomegranate bacterial blight disease by adopting advanced in silico tools. We have identified 46 putative copper-binding proteins (PCBPs) from Xcp, approximately 0.85% of the Xcp proteome, of which 34 and 25 PCBPs are essential and pathogen-host interaction (PHI) responsible proteins, respectively. Of the 25 PHI-responsible proteins, 9 are classified into classical secretory proteins and 8 are classified into non-classical secretory proteins. These PHI-responsible PCBPs are involved in diverse processes, including metabolism, response to oxidative stress, transport, protein folding, signalling, and virulence mechanism. Our study identified 16 drug target proteins among the PHI-responsible PCBPs, which can be used as an ideal target for various antimicrobial agents to control pomegranate blight disease. Our observations pave the way to the understanding of copper homeostasis in Xcp and its possible involvement in the disease-causing process.