Advances in Sustainable Agriculture and Horticulture: Towards Resilient, Productive, and Ecologically Sound Food Systems

Drought stress is a major abiotic constraint limiting global agricultural productivity and is expected to intensify under ongoing climate change, posing a significant threat to food security. Plants have evolved a wide range of adaptive mechanisms to cope with water deficit, including physiological, morphological, biochemical, and molecular responses that collectively enhance survival under stress conditions. Key physiological strategies include stomatal regulation, osmotic adjustment, and improved transpiration efficiency, which help maintain water balance and sustain metabolic activity. Morphological adaptations such as modified root architecture, reduced leaf area, increased trichome density, and cuticle thickening further contribute to minimising water loss and improving water uptake. At the biochemical level, plants activate antioxidant defence systems to mitigate drought-induced oxidative stress, while specialised species such as resurrection plants exhibit extreme desiccation tolerance through unique protective mechanisms. At the molecular level, drought stress triggers complex signalling networks involving abscisic acid (ABA), reactive oxygen species (ROS), calcium signalling, and protein kinases, leading to transcriptional reprogramming. Transcription factors such as DREB, bZIP, MYB, NAC, and WRKY families play critical roles in regulating stress-responsive genes, while long-distance signalling via mobile mRNAs coordinates systemic responses across plant tissues. Advances in plant breeding and biotechnology have significantly improved drought tolerance through the integration of conventional breeding, speed breeding, omics-assisted selection, and genome-editing tools such as CRISPR/Cas9. However, the quantitative nature of drought tolerance and strong genotype × environment interactions remain major challenges. Therefore, an integrated approach combining physiological insights, molecular understanding, and advanced breeding strategies is essential for developing resilient crop varieties capable of sustaining productivity under water-limited conditions.