Micronutrient and redox homeostasis contribute to Moringa oleifera-regulated drought tolerance in wheat

Global food security is being severely affected by the rapid increase in population and drastic climate change. Drought stress is the most important limiting factor for the sustainable production of several important crops, including wheat. The gradual temperature rise and reduced precipitations are likely to cause the frequent onset of droughts around the world. Therefore, alleviation of drought stress in crop plants has become an essential requirement to meet the increasing food demand. The present study explored the role of foliar application of Moringa leaf extract (MLE) in conferring drought tolerance in wheat during the anthesis stage. A wheat genotype of Indo-Gangetic Plains (HI1544) was exposed to drought stress during the anthesis of the spikes and simultaneously foliar sprayed with MLE for 10 days. The results showed the MLE treatment to improve the concentrations of macro- (K, Ca) and micronutrients (B, Cu, Fe, Mn, Zn, Si) in flag-leaves of wheat under non-stressed conditions. Application of MLE also maintained the flag-leaf nutritional contents under drought stress. The micro-nutrients, including Cu, Fe, Mn, and Zn being the co-factors of the enzymes also stimulated the antioxidant enzyme activities; eventually leading to a significant reduction in the reactive oxygen species and malondialdehyde accumulations under drought stress. Furthermore, micronutrients played a crucial role in osmotic adjustment and sustainable plant growth under drought stress. Overall, the study provided insights into the functional role of micronutrients in improving drought tolerance and also indicated the potential to commercialize MLE as an effective bio-stimulant for sustainable agriculture in drought-prone regions.