Rhizosphere microbiome dynamics and plant adaptation to abiotic stress in major oilseed crops: a review

Abiotic stresses, such as drought, salinity, extreme temperatures, nutrient deficiencies, and heavy metal contamination, severely limit oilseed crop productivity under accelerating climate change. This review synthesizes recent advances in understanding the critical role of soil and plant-associated microbiomes in conferring stress tolerance to major oilseed species, including rapeseed ( Brassica napus ), sunflower ( Helianthus annuus ), soybean ( Glycine max ), and sesame ( Sesamum indicum ). Beneficial microorganisms, particularly plant growth-promoting rhizobacteria (PGPR), arbuscular mycorrhizal fungi (AMF), and endophytes, enhance plant tolerance through an integrated network of biochemical, physiological, and molecular mechanisms. Biochemically, they modulate phytohormone levels (e.g., IAA and ABA), produce osmoprotectants, and regulate antioxidant systems (e.g., SOD, CAT, POD) to mitigate oxidative damage. Physiologically, these processes contribute to improved root architecture, water-use efficiency, nutrient acquisition, and ion homeostasis under stress conditions. At the molecular level, microorganisms influence gene expression and signaling pathways associated with stress responses, including activation of stress-responsive genes and metabolic adjustments. These interconnected mechanisms collectively strengthen plant resilience by coordinating metabolic regulation, cellular protection, and adaptive responses within the plant-microbiome system. Agroecological practices (soil type, crop rotation, tillage, fertilization) strongly shape microbial community assembly and functional potential, while multi-omics approaches (metagenomics, metatranscriptomics, metabolomics) reveal stress-driven restructuring and adaptive metabolic shifts in the rhizosphere. Emerging tools such as synthetic microbial consortia (SynComs) and targeted microbiome engineering offer promising, sustainable alternatives to conventional breeding and chemical interventions, enhancing soil health, nutrient cycling, and agroecosystem resilience with reduced environmental footprint. This review presents a comprehensive synthesis with a specific focus on oilseed crops, integrating current knowledge on microbiome dynamics under multiple abiotic stress conditions—an area that remains comparatively underrepresented in the literature. It examines key microbial groups driving adaptation, evaluates omics-based insights into plant-microbiome interactions, identifies critical research gaps, and outlines future directions for microbial inoculants and climate-resilient oilseed production systems.