Isolation and characterization of catalase and superoxi̇de di̇smutase in cabarla strawberry variety

ABSTRACT M.Sc. Thesis ISOLATION AND CHARACTERIZATION OF CATALASE AND SUPEROXİDE DİSMUTASE IN CABARLA STRAWBERRY VARIETY Songül CARUS Isparta University of Applied Sciences Graduate School of Natural and Applied Sciences Department of Agricultural Biotechnology Supervisor: Prof. Dr. Yaşar KARAKURT When exposed to the unsuitable environmental conditions the development of plants are affected negatively and this situation is called stress. There are two stress conditions for plants which are abiotic and biotic stresses. In order to decrease or prevent the negatif effects of the stress, plants have defence mechanisms. Under stres conditions ROSes interact with cell membran and the materials within the cell and thus negatively affect plant development. CAT and SOD are the most effective enzymes for combating and removing the ROSes. The catalase enzyme is one of the most effective protein catalysts encouraging the redox reactions. Catalase is an antioxidant enzyme localized in mitocondry and peroxisome, not available in chloroplast and cleaning the media from ROSes by converting the H2O2 to water and oxygen. Superoxide dismutase is a metalloprotein with an exceptional catalytic activity forming the first line of defence against the reactive oxygen species. The gene sequences of these enzymes that are very important for the defence against stres conditions have not been determined in many plants including strawberry. In this study, the genes encoding CAT and SOD antioxidant enzymes have been isolated, sequenced and characterized in Kabarla strawberry variety. For this purpose, degenerate primers have been designed and used in PCR reactions in order to obtain the partial cDNA sequences and then 3' and 5' RACE analyses have been conducted in order to obtain their full length sequences. According to the sequence results, CAT and SOD genes contained open reading frames encoding 496 and 317 amino acids respectively. The isolated CAT gene showed high level of similarity to the Solanum Lycopersicum and Prunus persica genes and the isolated SOD gene demonstrated high similarity to the Prunus persica SOD gene. These molecularly characterized genes could either be used for the characterization of similar genes in other plant species or for the development of new strawberry cultivars more resistant to the stres conditions. Keywords: Kabarla, antioxidant, catalese, süperokside dismutase. 2019, 50 page