Coordinated regulation of plant stress adaptation by ethylene and ABA: an overview

Abiotic stresses, including drought, salinity, temperature extremes and nutrient limitation, impair plant growth and crop productivity by disrupting water status, photosynthesis, ion balance and cellular redox homeostasis. Plant adaptation depends on the integration of hormonal signaling with retrograde cues from chloroplasts and mitochondria. Abscisic acid (ABA) is central to osmotic-stress responses, regulating stomatal closure, stress-responsive transcription and redox balance, whereas ethylene modulates growth inhibition, senescence and stress acclimation in a strongly context-dependent manner. Emerging evidence indicates that ABA and ethylene signaling converge with organelle-to-nucleus communication mediated by reactive oxygen species (ROS), tetrapyrrole/heme-related signals, 3′-phosphoadenosine 5′-phosphate (PAP), mitochondrial dysfunction signals and changes in photosynthetic status. These signals are integrated through shared regulatory nodes, including ABI4, EIN3/EIL1, ethylene response factors (ERFs), ABA-responsive transcription factors, SnRK2/Raf-like kinase modules, GUN1, RCD1 and ANAC017, thereby coordinating antioxidant defense, photosynthetic adjustment, stomatal behavior, senescence and stress acclimation. Depending on stress type, developmental stage and tissue context, ABA–ethylene interactions may be synergistic or antagonistic. However, the molecular mechanisms linking hormone biosynthesis, transcriptional control and retrograde signaling remain incompletely resolved. Clarifying these convergence points will improve mechanistic understanding of plant stress adaptation and support stress-resilient crop improvement.