Effect of norflurazon on responses of superoxide dismutase and catalase in a standard maize inbred line and superoxide dismutase mutant

We compared the responses of superoxide dismutase (SOD) and catalase (CAT) to a herbicide norflurazon (NF)-induced oxidative stress in leaves and mesocotyls of a standard maize (Zea mays) inbred line (W64A) to those of a SOD mutant (A130-1) having a mutation in Sod1. The changes in activities of SOD and CAT with NF treatment did not differ between W64A and A130-1. The relative transcript levels of Sod1 and Cat1 increased greatly in response to NF in leaves and mesocotyls of the two maize lines. In leaf and mesocotyl tissues, the Sod3 transcript increased only at a 33 μM NF in W64A, whereas Sod3 increased at 33 μM and 100 μM in A130-1. The Sod4A transcript increased only in mesocotyls of NF-treated A130-1, but the total Sod4A transcript level was much higher in W64A than in A130-1. Cat2 increased in the leaves of NF-treated W64A but decreased significantly in the leaves of A130-1. In mesocotyls, the Cat2 transcript increased only in A130-1 upon NF treatment. The maize variant with a mutation in Sod1 demonstrated differences in the induction of Sod and Cat transcripts from the standard inbred line W64A in response to NF-induced oxidative stress.