Crucifer Lesion-Associated Xanthomonas Strains Show Multi-Resistance to Heavy Metals and Antibiotics

Copper resistance in phytopathogens is a major challenge to crop production globally and is known to be driven by excessive use of copper-based pesticides. However, recent studies have shown co-selection of multiple heavy metal and antibiotic resistance genes in bacteria exposed to heavy metal and xenobiotics, which may impact the epidemiology of plant, animal, and human diseases. In this study, multi-resistance to heavy metals and antibiotics were evaluated in local Xanthomonas campestris pv. campestris (Xcc) and co-isolated Xanthomonas melonis (Xmel) strains from infected crucifer plants in Trinidad. Resistance to cobalt, cadmium, zinc, copper, and arsenic (V) was observed in both Xanthomonas species up to 25 mM. Heavy metal resistance (HMR) genes were found on a small plasmid-derived locus with 90