Changes of antioxidant enzymes of mung bean [Vigna radiata (L.) R. Wilczek] in response to host and non-host bacterial pathogens

The natural resistance against the majority of potential pathogens that exist in most plant species is known as non-host resistance. Several reports suggest the role of antioxidant enzymes in non-host resistance. We assayed the expression or activity of four scavenging enzymes during non-host pathogen-plant interaction (Xanthomonas hortorum pv. pelargonii/mung bean) and host pathogen-plant interaction (Xanthomonas axonopodis pv. phaseoli/mung bean). The expression of superoxide dismutase (SOD) and ascorbate peroxidase (APX) and the enzyme activity of catalase (CAT) and peroxidase (POX) were investigated. The activities of CAT and POX were higher during non-host pathogen invasion vs. host pathogen attack. The expression of SOD and APX were also different between compatible and incompatible interactions. The expression of SOD and APX were higher in the incompatible compared to the compatible interaction. Additionally, induction of the antioxidant enzymes in response to non-host pathogen was earlier than induction in response to host pathogen. Such information is important for plant breeders, and useful when looking for alternative control strategies as well.