A host-specific toxin of<b><i>Rhizoctonia solani</i></b>triggers superoxide dismutase (SOD) activity in rice

Abstract

Abstract Changes in the activity of superoxide dismutase (SOD) in rice in response to treatment with Rhizoctonia solani toxin and/or R. solani elicitor were studied. Treatment of rice leaf sheaths with R. solani-toxin significantly increased the SOD activity within 12 h and the maximum enzyme activity was detected 36 h after treatment at which period a fourfold increase in SOD activity was recorded compared to control plants. Isozyme analysis indicated that five new SOD isozymes (SOD-1, SOD-3, SOD-6, SOD-7 and SOD-8) were induced in rice 1 – 2 days after toxin treatment. In elicitor-treated rice leaf sheaths, SOD-2 increased in activity 1 – 5 days after treatment. Pretreatment of rice leaf sheaths with elicitor suppressed the toxin-induced accumulation of SOD. Keywords: ElicitorOryza sativaRhizoctonia solanisheath blightsuperoxide dismutasetoxin