The establishment of an efficient in vitro genetic transformation protocol in soybean depends upon an effective interaction between the explants and Agrobacterium tumefaciens. Therefore, a study was conducted at the University of Limpopo, South Africa, between September 2019 and May 2020 to evaluate explant amenability and effects of Agrobacterium co-cultivation stage on the induction of oxidative stress. This stress potentially causes lipid peroxidation, reduction of phytochemicals and chlorophyll pigments on explant tissue targeted for genetic transformation. This study, used double cotyledonary node explants infected and co-cultured with A. tumefaciens to evaluate total phenolics, antioxidant activity, lipid peroxidation and oxidative stress-induced tissue senescence during the co-cultivation stage. The results, showed that, explant co-cultivation with Agrobacterium for 2, 4 and 6 days caused reductions in the amounts of phenolic compounds, chlorophylls and antioxidant activity due to tissue senescence, high oxidative stress and malondialdehyde contents. Percentage phenolic content of all bacteria infected explants ranged between 10.3?10.6 compared to 20.9% in the control. Chlorophyll content of about 1.49?4.00 mg/ml and malondialdehyde content ranging between 1.0?5.7 mM-1g-1 were also recorded. Overall, findings suggest that the infection of explants with A. tumefaciens can induce oxidative stress and tissue senescence depending on the period of co-cultivation. However, reduced oxidative stress and senescence of explant tissues may potentially improve soybean shoot regeneration and transformation efficiency.
CONSTRUCTION OF THE FeSOD ANTI-OXIDATIVE STRESS GENE FOR THE GENETIC TRANSFORMATION OF SOY
