Regulation of antioxidant enzymes by abscisic acid and salicylic acid under biotic stress caused by Fusarium fujikuroi in rice

Abstract

Abscisic acid and salicylic acid regulations of antioxidant enzymes were studied in shoots and roots of rice cultivars Punjab Mehak 1 (resistant) and Pusa Basmati 1121 (susceptible) in the presence and absence of Fusarium fujikuroi (Ff). Hormonal increase of H2O2/nitric oxide (NO) and antioxidant enzymes in the absence and presence of Ff was found much higher in Punjab Mehak 1 compared to Pusa Basmati 1121. Under Ff, H2O2 levels remained unaltered accompanied high activities of antioxidant enzymes in shoots and roots of Punjab Mehak 1 while in Pusa Basmati 1121, NO signals and some antioxidant enzymes increased but H2O2 signals decreased in shoots while in roots, H2O2/NO and antioxidant enzymes decreased by large amount where Ff + hormone applications improved H2O2/NO to some extent but improved enzymes poorly. However, Ff + hormones applications reduced seed mortality and percent infections effectively in Pusa Basmati 1121 where ABA decreased percent infection and SA decreased seed mortality by high amount. Overall results showed antioxidant enzymes as vital constituents of resistance in Punjab Mehak 1 but in Pusa Basmati 1121, poor induction probably be the reason as enzymes were not induced effectively even when hormones supplied from outside.