Effect of rol Genes of the A4, 15834, and K599 Strains of Agrobacterium rhizogenes on Root Growth and States of the Antioxidant Systems of Transgenic Tobacco Plants Subjected to Abiotic Stress

Abstract An attempt is made to create transgenic plants using rol genes from A4, 15834, and K599 strains of A. rhizogenes . Strains A4 and 15834 transformed tobacco plants are found to display better root growth than their wild types under normal conditions and at elevated concentrations of sodium chloride or cadmium acetate. At the same time, the rol genes acquired from the K599 strain negatively affect root growth under both normal and stressful conditions (e.g., salinization, hypothermia, or excess cadmium acetate). The levels of total protein, proline, total glutathione, and superoxide dismutase activity are higher in the roots of the transgenic plants with rol genes from the A4 and 15834 strains than in nontransgenic control plants under both optimum conditions and salinization. When using rol transgenes from the K599 strain, the activities of superoxide dismutase, guaiacol peroxidase, and glutathione-S-transferase are enhanced in the roots subjected to salinization. The positive effect rol genes have on the root growth of transgenic plants could therefore be explained by their influence on components of the antioxidant system. Results suggest that using rol genes from the A4 and 15834 strains of A. rhizogenes are promising for breeding plant cultivars and liness with improved parameters of root growth and stress tolerance. At the same time, rol genes from the K599 strain appear to be inadequate for this task.