Revolutionizing drought defense: The water-plant-microbe synergy in climate-smart agriculture.

Global warming-induced water scarcity threatens agricultural sustainability. While precision irrigation and microbial inoculants are recognized as effective individual strategies, their synergistic potential remains under-explored. This review synthesizes recent advances in the "water-plant-microbe" synergy to propose a bidirectional regulatory mechanism for climate-smart agriculture. We demonstrate that irrigation regimes function as a primary filter for rhizosphere microbial assembly, thereby defining the hydraulic niche for colonization. Conversely, functional microbes actively engineer the soil environment via exopolysaccharide production and hormonal modulation, thereby enhancing plant hydraulic status and water use efficiency (WUE). In contrast to previous reviews focusing on single factors, this review constructs an integrated framework linking soil hydrology with microbial ecology, supported by emerging comparative evidence. We conclude that future agricultural water management must shift from solely regulating water supply to managing the holobiont's hydrological interactions, offering a promising systems-level strategy to safeguard food security under climate stress.