Oryzacystatin-I Expressing Tobacco Plants: Gene Expression and Plant Performance Under Abiotic Stress

Although several studies have shown increased tolerance of engineered plants to abiotic stress, levels of expression and stability of the transgene are still stumbling blocks to achieve optimal efficiency. This study has addressed this problem by studying transgene expression and stability under stress and their potential benefits to the plants. In particular, the expression and stability of a cysteine proteinase inhibitor (OC-I) expressed in tobacco has been investigated under drought, heat and combination of both stresses. A specific focus of the study was on evaluating potential benefits of the stable expression of OC-I transgene by measuring growth and physiological performances of plants under individual and combined stresses. This also included investigating possible effect of OC-I overexpression on gene expression in plans. A further aspect of the study focused on the effect of OC-I expression in stabilizing plant proteins. The study finally identified and characterized two novel papain-like tobacco cysteine proteinases as possible targets of expressed OC-I.