Expression of oxidative burst in cultured cells of pearl millet cultivars against Sclerospora graminicola inoculation and elicitor treatment

Abstract

Treatment of cultured cells of pearl millet cultivars with salicylic acid, calcium chloride zoospore, sporangial suspension and sporangial cell wall components of Sclerospora graminicola, a downy mildew disease causing pathogen elicited oxidative burst. The characteristics of the enzymatic production were similar in both compatible and incompatible interaction but the kinetics and intensity of production of active oxygen species (AOS) differed among the interactions. Biphasic oxidative burst was recorded in incompatible interaction. Inhibition studies with diphenylene iodonium, azide and cyanide showed that the key enzyme responsible for oxidative burst in pearl millet is NADPH oxidase and contribution of peroxidase towards oxidative burst was less. These results were further confirmed by the increase of AOS production by nicontinamide adenine dinucleotide and inhibition recorded by superoxide dismutase and catalase on oxidative burst. Oxidative burst studied in different cultivars of pearl millet with varied degree of resistance to downy mildew disease showed the correlation of oxidative burst with host resistance.