Microbial allies for salinity resilience: Mechanisms, innovations, and holobiont strategies for sustainable crop production

Abstract

Soil salinity poses a major constraint to global agricultural productivity, affecting millions of hectares and causing substantial economic losses annually. Conventional reclamation strategies are often unsustainable, highlighting the urgent need for innovative biotechnological solutions to safeguard food security. The present review focuses on the critical role of beneficial microorganisms, including plant growth-promoting rhizobacteria (PGPR), endophytic fungi, and arbuscular mycorrhizal fungi, in enhancing plant tolerance to saline stress. These microbial associates employ multifaceted mechanisms to mitigate salinity-induced damage, including modulating phytohormone signaling, improving nutrient acquisition through mineral solubilization, and maintaining ionic homeostasis through selective sodium exclusion and enhanced potassium uptake. Additionally, beneficial microbes stimulate the accumulation of compatible osmolytes and activate antioxidant defense systems, collectively preserving cellular turgor and reducing oxidative stress. Here we highlight the genetic diversity and metabolic versatility of halotolerant strains from genera such as Bacillus, Pseudomonas, and Azospirillum, underscoring their potential as effective bio-inoculants. Finally, emerging research directions are discussed, emphasizing the synergistic application of microbial consortia and the integration of multi-omics approaches to elucidate complex plant-microbe-salinity interactions, providing a roadmap for sustainable saline agriculture.