Influence of brassinosteroied and cytokinin hormones spray on activity and gene expression of catalase and proline in two cultivars of canola under drought stress

Abiotic stress is a limiting factor for plant products. The most common reaction under drought and saline stresses is proline accumulation as a protective osmotic action. Drought stress causes to produce reactive oxygen species by reducing plant water. This reactive oxygen species injured the cell by demolition proteins, amino acids, chlorophyll and DNA. To reducing these injurious, plants possess antioxidant defense systems such as catalase (CAT) which its main obligation is to decompose hydrogen peroxide. The best way to confrontation with drought stress is using the plant growth regulators that not only cause to plant growth and cell division, but also is a contributing factor for gene expression, producing nucleic acids and proteins. In this assay we conducted an experiment on the effect of Cytokinin and Brassinosteroied hormone's on proline content, catalase activity and their gene expression under drought stress in two Cultivars called OKAPI and GKH. This experiment was conducted as factorial based on CRD design with three replicates in greenhouse at laboratory of Agricultural Biotechnology Research Institute of Iran (ABRII) in 2012. The results showed that both varieties of rapeseed, GKH and OKAPI have the highest CAT activity in term of drought stress on Brassinosteroied hormone levels, moreover it cleared up that there is a significant difference with the control (non hormone spray). The results of Cat16 gene expression assay showed that the both cultivars in drought stress had the maximum gene expression in hormone levels Brassinosteroied and Cytokinin 100 mM + Brassinosteroied. Also the results showed that the highest mean values for cat54 gene expression was for Brassinosteroied hormone with expression level more than three times relation to non hormone spray. The content of proline and p5cs gene expression in levels of hormone spray was rising in GKH and reduced in OKAPI, respectively.