Navigating PIFs and phytochromes: Key players in plant development and resilience to drought and other abiotic stresses

Plants frequently encounter abiotic stresses, with drought being a major limitation growth and productivity. Phytochromes, the primary red/far-red light receptors, perceive environmental signals and initiate downstream responses. Phytochrome-Interacting Factors (PIFs) act as key regulators by linking light signaling with hormonal pathways, particularly abscisic acid (ABA), to control stomatal conductance, antioxidant activity, and osmotic balance. PIFs contribute to drought tolerance by modulating stress-responsive gene expression and coordinating growth with adaptation. Isoform-specific roles have been observed in different species; for instance, NtPIF1 negatively affects drought tolerance in tobacco, whereas MdPIF3 enhances drought resistance in apple and Arabidopsis. These contrasting functions highlight the complexity of PIF-mediated stress regulation. Crosstalk with other hormone such as ethylene, jasmonic acid, brassinosteroids, and salicylic acid further shapes PIF activity and drought responses. This review highlights the role of phytochromes and PIFs in drought responses, their integration with ABA and other hormonal pathways, and their potential as targets to enhance crop resilience under adverse environmental conditions.