1 research outputs found

    Reactive oxygen species and ascorbate–glutathione interplay in signaling and stress responses in Sesamum orientale L. against Alternaria sesami (Kawamura) Mohanty and Behera

    Get PDF
    Sesamum orientale wild and cultivar Thilarani exposed to Alternaria sesami infection triggered the signal cascade H2O2 content that was positively correlated with lipid peroxidation. The data were also supported by H2O2 localization as observed by scanning electron microscopy. Parallely, infection altered chloroplasts marginally and mitochondria effectively in susceptible cultivar than wild sesame. Deformities in the structure of these organelles were accompanied by changes in antioxidant machinery. H2O2 can be effectively detoxified via the ascorbate–glutathione cycle. Increases in ascorbate peroxidase, and glutathione reductase activities concomitant with ascorbate (AsA) and glutathione interplay, as well as AsA regeneration ability, function to keep the balance of cellular H2O2 under pathogenicity. Dehydroascorbate reductase and monodehydroascorbate reductase are responsible for AsA regeneration. Oxidative damage in Thilarani cultivar compared to wild sesame is attributed by a lower induction of the ascorbate–glutathione cycle as an antioxidant defense system and was not sufficient to protect mitochondria but prevent ultrastructural damage of chloroplasts. Overall, the availability of antioxidants and the induction of antioxidant enzyme activities for detoxifying reactive oxygen species (ROS) are regulated effectively in wild sesame against A. sesami induced oxidative stress. The experiments using ROS scavengers demonstrate that the antioxidant defense system is modulated by O2−·− or H2O2 signals
    corecore