Crop Resilience to Combined Drought and Salinity Stress in Drylands: From Soil Processes to Genomic Solutions.

Abstract

Drought and soil salinization increasingly co‑occur, threatening global food security, particularly in dryland farming systems where these stresses can interact additively, synergistically or antagonistically to reduce crop yields. This review critically distinguishes these interaction types and moves beyond single‑stress frameworks to provide a multiscale synthesis of plant responses, soil water-salt dynamics, root‑system plasticity, rhizosphere microbiome modulation, emerging breeding modelling and agronomic tools. This review provides a detailed overview of the multilevel damage from these co-occurring stresses, including osmotic shock, ionic toxicity and systemic oxidative damage, and examines plant strategies such as ion homoeostasis, osmotic adjustment and antioxidant responses. Beyond plant-centric views, the review explores epigenetic reprogramming for stress memory and the potential of rhizosphere microbiome engineering with plant growth-promoting rhizobacteria as a biological stress-alleviation strategy. It critically examines how high-throughput multiomics techniques, combined with innovative breeding methods, provide a transformative approach to decode complex tolerance traits and accelerate cultivar development. These techniques cover genomics, epigenomics, transcriptomics, proteomics and metabolomics, while the breeding methods include genomic selection and CRISPR-Cas gene editing. Despite progress, key challenges remain: validating combined stress resilience under field conditions, harnessing epigenetic inheritance and integrating microbial solutions into breeding pipelines. We propose a unified framework that merges mechanistic discovery, microbiome-assisted breeding, soil and water management and systems-level predictive modelling. This integrative approach is essential for developing climate-resilient crops to sustain dryland agriculture.