Changes in activity of superoxide dismutase and catalase within cereal aphids in response to plant o-dihydroxyphenols

Abstract:  Superoxide dismutase and catalase activity was found in the bird cherry-oat aphid, Rhopalosiphum padi (L.) and the grain aphid, Sitobion avenae (F.). Among the aphid morphs studied, the highest activity of the antioxidant enzymes was noted for winged adults (alatae) and the lowest for wingless (apterae) ones. Higher activity of superoxide dismutase and catalase was observed in the polyphagous species R. padi that alternates between woody host plants and grasses. On some ocassions, activity of superoxide dismutase in cereal aphids was increased by twofold, when aphids were exposed to toxic plant o -dihydroxyphenols. An opposite tendency was observed in case of activity of the catalase that was strongly reduced within body of phenolics-treated insects. Among the plant allelochemicals studied, caffeic acid showed the strongest effect on the activity of the antioxidant enzymes of the cereal aphids. The experiments carried out indicate that antioxidant enzymes might play an important role in interactions between cereal aphids and their host plants.