Plant adaptations to soil stress through hormonal signaling and microbial interactions
摘要
Soil stresses such as drought, salinity, nutrient deficiencies, and heavy metal toxicity severely constrain plant growth by disrupting root function, nutrient uptake, and beneficial soil interactions. In response, plants depend on stress-responsive hormones—particularly abscisic acid (ABA), jasmonic acid (JA), ethylene, strigolactones, and auxins—to adapt and survive. These hormones remodel root architecture, regulate stomatal closure to conserve water, and fine-tune internal signaling to sustain growth under adverse conditions. JA plays a key role in phosphorus uptake and cell wall repair, while ABA modulates root development and water use under drought and salt stress. Strigolactones enhance nutrient foraging efficiency, and hormonal crosstalk mitigates ammonium toxicity. Increasingly, soil microbes are recognised as active partners in stress mitigation, producing or modulating phytohormones such as indole-3-acetic acid (IAA) and ABA, improving nutrient availability, and inducing systemic tolerance. Beneficial rhizobacteria and mycorrhizal fungi also enhance root plasticity, water use efficiency, and soil health. While exogenous hormone applications show potential, concerns about cost, environmental safety, and soil health underscore the need for sustainable approaches. Microbial inoculants, natural hormone analogues, and precision delivery systems are emerging as integrated solutions. This review synthesizes current understanding of the interplay between soil stresses, phytohormones, and plant–microbe interactions, offering a comprehensive perspective for developing resilient and sustainable crop production systems.