Phytohormone Networks Orchestrating Lateral Organ Adaptations to Hypoxia and Reoxygenation in Fruit Crops.

Abstract

The increasing severity and frequency of climate extremes threaten global fruit production. Among these, waterlogging-induced hypoxia and subsequent reoxygenation represent devastating yet understudied challenges. Major rainfall events disrupt rhizosphere oxygen dynamics, triggering metabolic dysfunction and growth impairment in economically vital fruit crops. This review elucidates cutting-edge knowledge on how phytohormonal networks-centred on auxin, ethylene, gibberellin, abscisic acid, and jasmonic acid-mastermind the plasticity of lateral organs by modulating adaptive responses such as adventitious root initiation, aerenchyma development, shoot elongation, and metabolic reprogramming during hypoxia and reoxygenation cycles. While extensive research in model plants has unveiled intricate hormonal interplay by optimising root architecture and shoot growth in stress adaptation strategies, corresponding regulatory networks in fruit crops remain poorly understood. Although progress has been made in deciphering hypoxia responses, shedding light on species-specific hormonal reprogramming and molecular insights into hormonal crosstalk, the reoxygenation phase is often overlooked. We also emphasise recent advances in understanding the interplay between hormonal biosynthesis, signalling, and cross-regulatory mechanisms that determine plant survival and recovery under fluctuating oxygen conditions. By integrating genetic, metabolic, and hormonal research, this review aims to uncover strategies for enhancing fruit crop resilience to oxygen fluctuations, offering solutions to climate-driven challenges in horticulture.