Plasticity and adaptive architecture of roots for enhanced salinity tolerance in crops

Soil salinization poses a major challenge to global food security, affecting over one billion hectares of arable land and severely constraining crop productivity. As the primary interface between plants and soil, roots play a pivotal role in sensing and adapting to salinity stress through remarkable structural and functional plasticity. This review integrates recent advances in root system architecture (RSA) dynamics, suberin biosynthesis, hormonal regulation, and microbiome interactions to elucidate how plants achieve salinity resilience. We discuss key genes and regulatory modules controlling primary root elongation, lateral root patterning, and barrier formation, emphasizing transcriptional networks involving MYB, NAC, and WRKY families and their coordination with ABA, auxin, and ethylene signaling. Special attention is given to the biosynthesis and deposition of suberin as a dynamic ion-selective barrier governed by hormonal crosstalk and lipid metabolism. We further highlight how beneficial microbes such as Azospirillum, Bacillus, and arbuscular mycorrhizal fungi enhance salt tolerance by modulating phytohormones, antioxidant systems, and ionic homeostasis. Integrating multi-omics and CRISPR-based tools with microbiome engineering offers new avenues to design salt-resilient root ideotypes. We propose a conceptual framework linking molecular regulation, hormonal dynamics, and rhizosphere ecology to root system plasticity, providing a blueprint for engineering next-generation crops capable of maintaining growth and productivity in saline environments.