Dynamics of redox imbalance, antioxidant defense network, and regulation of aquaporin-mediated water transport in contrasting maize (Zea mays L.) genotypes in response to drought stress.

Drought is one of the severe environmental stressors that drastically impair plant growth and yield. In this study, we have screened diverse maize genotypes and selected PMI-PV9 and PMI-PV4 as drought-tolerant and drought-sensitive maize inbred lines, respectively. Expression of aquaporins and dehydrin, relative water content, membrane damage, ROS generation, osmolytes accumulation, ABA level, stomatal behaviour, and modulation of ascorbate-glutathione cycle were compared among the selected maize genotypes to better understand the plant drought stress response mechanisms. Upon drought exposure, PMI-PV9 genotype exhibited better seedling growth over PMI-PV4 plants. Enhanced expression of ZmPIP1;1 , ZmPIP1;3, and ZmTIP2;1 transporters, DHN1 and DREB1 might render the PMI-PV9 plants more efficient to withstand the drought condition by regulating ion-water homeostasis, maintaining cell turgidity and membrane stability. In a nutshell, our findings suggest that the disruption in cellular redox equilibrium due to meagre antioxidant defence mechanism might be the prime reason behind the oxidative burst leading poor performance of PMI-PV4 plants under water deficit condition. To our best knowledge, this is the first study that simultaneously integrates redox homeostasis, aquaporin regulation, and dehydrin expression to deepen our understanding of drought tolerance mechanisms in contrasting maize genotypes. Overall, the present investigation highlights PMI-PV9 as a promising parental line for breeding program to develop high-yielding maize hybrids with enhanced drought tolerance. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-025-01684-1.