Role of Rhizosphere Microbiomes in Phytoremediation of Petroleum-Contaminated Soils

Petroleum hydrocarbon contamination poses a significant threat to terrestrial ecosystems and human health worldwide. Phytoremediation, the use of plants and their associated microorganisms to degrade or remove contaminants, has emerged as a sustainable and cost-effective alternative to physical and chemical remediation methods. The rhizosphere microbiome, the complex microbial community inhabiting the plant root zone, plays a pivotal role in the success of phytoremediation by enhancing pollutant degradation, promoting plant growth, and alleviating contaminant-induced stress. This review synthesizes current knowledge on the mechanisms by which rhizosphere microbiomes contribute to the phytoremediation of petroleum-contaminated soils, including rhizodegradation, plant growth promotion, and stress mitigation. We discuss the key factors influencing the composition and function of petroleum-degrading rhizosphere communities, such as plant species, contaminant properties, and soil conditions. Emerging strategies to enhance phytoremediation efficiency, including biostimulation, bioaugmentation, and rhizosphere engineering, are critically evaluated. The application of advanced molecular techniques, including multi-omics approaches, to elucidate plant-microbe-pollutant interactions is highlighted. A simplified conceptual model is presented to illustrate the integrated processes involved in rhizosphere-mediated phytoremediation. The review concludes by identifying knowledge gaps and future research directions necessary to optimize and scale up this promising bioremediation strategy for field application.