Abstract

The objective of this study was to investigate changes in enzymatic activity and gene expression related to antioxidant defense in two passion fruit cultivars (FB100 and FB200) exposed to aluminum. The specific activity of superoxide dismutase (SOD), catalase and ascorbate peroxidase were analyzed, in addition to their relative expression pattern. The characterization of gene expression was achieved by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) technique followed by densitometric analysis. Plants were irrigated every two days with a nutrient solution: pH 6; pH 4; 0.2 and 2.0 mM Al (pH 4). The leaves were collected at the times 0 h, 2 days, 5 days and 10 days. The analysis of the potential oxidative stress induced by aluminum demonstrated increased expression of catalase and superoxide dismutase gene, and only on the cultivar FB100 this increase was accompanied by an increase of SOD enzymatic activity, which indicates its higher efficiency on the removal of reactive oxygen species (ROS) compared to cultivar FB200.  

Key words: oxidative stress, Passiflora edulis, aluminum, semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), differential expression.