Bioengineering Enhanced Antioxidant Systems in Transgenic Plants – Strategies, Outcomes, and Challenges: A Review

Reactive oxygen species (ROS) such as superoxide radicals, hydrogen peroxide and hydroxyl radicals are continuously synthesized in plants and can cause adverse effects when coupled with abiotic stress. Such stresses include salinity, cold environment, UV radiation, and more. Excess production of ROS can cause adverse effects like lipid peroxidation, increase in protein denaturation, membrane damage, and impaired photosynthesis. To solve such an issue, plants rely on a coordinated antioxidant network consisting of both enzymatic and non-enzymatic antioxidant components. The progress in plant genetic engineering has enabled targeted enhancement of these antioxidant systems which in turn improves stress tolerance and productivity. Strategies such as overexpression of individual antioxidant enzymes, organelle-targeted expression, multi-gene stacking within pathways like the AsA-GSH cycle and metabolic engineering of non-enzymatic antioxidants have introduced new methods of protecting plants from deleterious ROS species. Cases studied include transgenic Nicotiana tabacum, Solanum lycopersicum, and other species. These cases tell us the substantial improvements in detoxification of ROS in affected plants by getting results that include reduction in lipid peroxidation and stabilized photosynthetic performance under abiotic stress. Despite this, however, several challenges remain in balancing ROS homeostasis, optimizing promoter choice, avoiding metabolic bottlenecks and even managing gene-dosage effects. This review talks about strategies, outcomes and challenges that you can face when bioengineering enhanced antioxidant systems in transgenic plants.