which is highly susceptible to Xcc, calamondin and kumquat leaves challenged with Xcc developed rapid
necrosis, resembling a hypersensitive reaction. Fluorescent microscopy examination identified fluorescent
materials around the necrotic lesions in kumquat and calamondin leaves challenged with Xcc, but
not in Mexican lime. The resistant cultivars inoculated with Xcc exhibited lower antioxidant enzymatic
activities and accumulated less H2O2. These modifications serve as physical barriers to ward off pathogen,
thereby suppressing lesion development.