ROS mediated response in blister blight disease compatibility of tea [Camellia sinensis (L.) O. Kuntze]

Blister blight, caused by the basidiomycete Exobasidium vexans infecting on the young leaves and shoots, influence greatly in the production and quality of tea. In-planta metabolic regulations vary with the stress tolerance aptitude of the genotypes. Reactive oxygen species (ROS), secondary metabolites, and antioxidative enzymes are among such parameters that have a significant impact in conferring tolerance. In situ ROS accumulation, oxidative damage, and subsequent enzymatic and non-enzymatic indicators in tender leaves of two each of susceptible (Happy Valley-39, Tukdah-78) and tolerant genotypes (Amberi valai-2, Phoobsering-312) were considered. The tolerant genotypes exhibited higher ROS, lipid peroxidation, and total protein content compared to the sensitive ones. Oxidative responses enumerate in terms of superoxide anion (O-2(-)), hydrogen peroxide (H2O2), and malondialdehyde, triggered activity of stress-responsive enzymes like superoxide dismutase, catalase, peroxidase, and glutathione S-transferase. Non-enzymatic secondary metabolites, especially flavonols were observed to be augmented in the sensitive genotypes.