Antioxidant Response of Mexican Lime to Xanthomonas citri subsp. citri

Mexican lime(Citrus aurantifolia) is one of the susceptible citrus genotype to Xanthomonas citri subsp. citri (Xcc) which is grown in the south and south-west of Iran. The disease infects all aerial parts of Mexican lime and severely infected plants show defoliation, badly fruit, premature fruit drop, twig dieback and general tree decline. In this study, Mexican lime leaves were artificially inoculated with Xcc to determine the effect of Xcc infections on antioxidant enzymes activity such as superoxide dismutase (SOD), guaiacol peroxidase (GP), catalase (CAT) and ascorbate peroxidase (APOD). These results indicated that CAT activity was significantly higher in infected leaves than controls. No effect on SOD activity was observed in infected leaves. The result also showed that POD was significantly increased at 2, 5 and 7 days post inoculation. While, APOD activity was higher than control in inoculated leaves during infected period with Xcc, considering that the results was significant only in 2 and 10 days post inoculation. Current results can present new approaches in the future researches in order to control CBC via transformation of plant defense.