Editorial: Fruit Trees Under Stress: Physiological, Biochemical, and Molecular Mechanisms

Wenming Qiu^*

• Hubei Key Laboratory of Germplasm Innovation and Utilization of Fruit Trees, Research Institute of Fruit and Tea, Hubei Academy of Agricultural Sciences, Wuhan, China

that modulate salicylic acid (SA), jasmonic acid (JA), and indole-3-acetic acid (IAA) levels to fine-tune resistance. CmMES1.1/CmMES1.5 boost SA content and CBC tolerance, while CmMES10.2/CmMES17.3 increase JA/IAA levels and susceptibility, which provided actionable targets for CBC-tolerant citrus breeding.Abiotic cues and environmental fluctuations also shape fruit tree performance and quality. Zhang et al. uncover a light-mediated regulatory cascade in pear, showing that the AGL8-LFY transcription factor complex directly activates PpPSY (a rate-limiting enzyme in β-carotene biosynthesis), which linked light signaling to carotenoid accumulation and fruit peel coloration. This finding explains the significant reduction in β-carotene content in bagged (shaded) fruits compared to non-bagged counterparts, offering a molecular basis for optimizing light management to improve fruit nutritional quality. Beyond discrete stressors, Gariglio et al.'s review synthesizes the "epidermal growth control hypothesis" to explain water relations in growing fruits, emphasizing how skin-flesh tissue crosstalk mediated by turgor pressure, osmotic potential, and sugar gradients-drives physiological disorders (e.g., cracking, purple spot). This framework bridges developmental biology and stress physiology, providing a holistic perspective for mitigating abiotic stress-induced losses.Collectively, these studies advance stress biology by identifying core molecular players (e.g., AcWRKY75, MES genes) and conserved pathways, validating key research tools, and highlighting tissue/species-specific adaptations. Future research should prioritize field validation of regulators, deciphering rootstock-scion crosstalk, developing multi-stress tolerant cultivars, and integrating multi-omics. Translating these findings into practical solutions will enhance fruit tree resilience amid climate change and pathogen pressures.On behalf of all editors in this Research Topic, i want to thank all authors for their rigorous contributions, the reviewers for their insightful feedback, and the Frontiers in Plant Science team for supporting this Research Topic. These studies collectively lay the groundwork for a comprehensive understanding of fruit tree stress biology, paving the way for sustainable and resilient horticultural production.