Heat Stress Modulates Superoxide and Hydrogen Peroxide Dismutation and Starch Synthesis during Tuber Development in Potato

Abstract

Potato production is being affected by high temperature stresses worldwide due to global warming. The biological basis of carbohydrate metabolism and reactive oxygen species (ROS) activity in potato tubers under high temperature stress is yet to be clearly understood. We evaluated the activities of two of the most important primary ROS members: superoxide (O₂.⁻) and hydrogen peroxide (H₂O₂) and their scavengers to understand the effects of heat stress on the changes of carbohydrates in growing tubers of five potato varieties including heat-tolerant and heat‐susceptible check varieties. The enzymatic ROS-scavengers were found to be differentially activated in these genotypes. The detoxification mechanism was more efficient in dual-stress (heat and salt) tolerant variety compared to single-stress tolerant variety. The antioxidant activity was increased by several folds in the tolerant variety compared to the susceptible variety. Storage starch accumulation and its composition was affected by O₂.⁻ and H₂O₂ metabolisms in potato tuber. The findings will be helpful in understanding the biological basis of the effect of ROS-detoxification on starch accumulation in growing tubers under heat stress.