Unravelling the role of adventitious roots under priming-induced tolerance to waterlogging stress in wheat

Waterlogging is a significant environmental stressor that can have detrimental effects on crop yields. Waterlogging priming has emerged as a promising technique for enhancing plant waterlogging tolerance. However, the underlying mechanisms behind the regulation of root resistance, particularly adventitious roots (ARs), in wheat under waterlogging stress remain unclear. In this study, we subjected plants to waterlogging priming for two days at the two-leaf stage, followed by seven days of waterlogging stress after a ten-day recovery period to investigate the morphological and anatomical structure and physiological functions of ARs in wheat. Our results demonstrated that primed plants under waterlogging stress (PW) had increased numbers of ARs, improved gas exchange, and enhanced aerenchyma formation in ARs, leading to normal plant respiration when compared to non-primed plants under waterlogging stress treatment (CW). PW up-regulated the expression of cell wall remodeling genes (CEL, XET), reactive oxygen species (ROS) production-related gene (RBOH1), and ethylene biosynthesis-related genes (ACS2, ACS4) in ARs, and increased anaerobic respiratory enzyme activity, thus preserving the supply of soluble sugars in ARs and providing more materials and energy for adventitious root regeneration compared to CW. Overall, waterlogging priming improved the waterlogging tolerance of both above-ground and ARs in wheat, reducing the severity of damage caused by waterlogging. Our findings provide new insights into the mechanisms underlying waterlogging priming and suggest that it may be a promising strategy for mitigating the adverse effects of waterlogging on crop productivity.