Advancements in Functional Endophytic Bacterium-Assisted Phytoremediation of PHC-Contaminated Soils: A Review

Petroleum hydrocarbons (PHC) are organic pollutants that pose serious health risks to humans and the environment. Treating soils contaminated with these persistent pollutants is a global concern that is challenging to implement effectively. Synergistic remediation strategies, particularly those involving plants and functional endophytic bacteria, offer ecologically sustainable approaches for remediating PHC-contaminated soil and thus hold broad application prospects. This review collected the literature from databases including Elsevier, Web of Science, PubMed, and CNKI, using keywords such as endophytic bacteria, petroleum hydrocarbons, plants, microorganisms, polycyclic aromatic hydrocarbons, and alkanes. After screening the titles, abstracts, and secondary headings, 123 articles were selected for narrative synthesis. It systematically elaborates on the types, functions, sources, and distribution characteristics within plants of hydrocarbon-degrading endophytic bacteria. It comprehensively summarizes the key molecular pathways involved in the bacterial degradation of alkanes and polycyclic aromatic hydrocarbons (PAHs). Furthermore, from four dimensions—PHC metabolism modes, plant growth promotion (PGP), production of biosurfactants (PBS), and horizontal gene transfer—this article innovatively analyzes the mechanisms underlying the synergistic remediation of petroleum hydrocarbon-contaminated soil through functional bacterium–plant interactions. Finally, the review outlines future research directions in the field, providing a theoretical foundation and practical pathways for advancing green remediation strategies for PHC-polluted soil.