Soil and Root-Associated Microbial Responses to Abiotic Stress under Climate Change: Implications for Carbon Cycling, Plant Resilience, and Microbial Bioinoculants

Abstract

Soil and root-associated microbial communities are pivotal to terrestrial biogeochemical cycling; however, compounding global change stressors increasingly compromise their structural and functional resilience. This review synthesizes microbial responses to key abiotic perturbations, including elevated atmospheric CO2 (eCO2), thermal anomalies, hydrological extremes (drought and flooding), and nutrient imbalances (N and P). We critically evaluate how these factors regulate microbial carbon use efficiency (CUE), greenhouse gas emissions, and the distribution of metabolic traits, specifically the balance between fast-growing (r-strategists) and slow-growing (K-strategists) populations. We also explore mechanisms of plant-microbe interactions under stress, focusing on root exudation patterns and phytohormone signaling (e.g., ethylene modulation via ACC deaminase). By bridging microbial physiology, metagenomics, and trait-based ecology, this study underscores the critical need to parameterize soil microbial mechanisms into climate feedback models to advance ecosystem management, ensure crop resilience, and improve the efficacy of soil bioinoculants.