Determination of antioxidant enzymes level in healthy and tapping panel dryness (TPD) syndrome affected bark tissues of rubber tree (Hevea brasiliensis Muell. Arg.)

Abstract

Oxidative stress may lead to overproduction of reactive oxygen species (ROS) which are highly toxic ultimately cause stimulation of antioxidant enzymes and damages to proteins, lipids, carbohydrates and DNA molecules in bark tissue of Hevea brasiliensis during onset of Tapping panel dryness syndrome (TPD). In this study, Antioxidant enzymes level in bark tissues of seven different healthy and TPD affected clones of Hevea brasiliensis namely RRII 105, PB 217, PB 235, PB 285, PB 5/51, PCK2 and GT1 was determined to monitor TPD occurrence. The results revealed that increased level of antioxidant enzymes activity was noticed in bark tissues of TPD affected clones while it was found to be low in healthy clones. Maximum level of superoxide dismutase (SOD) activity noticed was 0.634 U/mg FW in healthy PB 5/51 clone compared with its TPD affected clone. The CAT activity was also found to be high in healthy PB 5/51 clone (1.988 U/mg) than TPD affected clone. In the case of peroxidase (POX) activity, it was found to be low in all healthy clones while the activity was significantly increased in TPD affected clones and maximum activity was noticed in PCK2 followed by PB285. Antioxidant enzymes level was also determined by native PAGE analysis and its results showed that isoenzymes of SOD and POX banding pattern are directly correlated with biochemical assays activity. This research correlates the activities of antioxidant enzymes between healthy and TPD affected clones and paves the path to understand the role of SOD, CAT and POX during onset of TPD and leads to future genetic studies on antioxidant enzymes and its genes in Hevea brasiliensis.