Perfluorooctanoic acid (PFOA), a synthetic perfluoroalkyl compound, has caused extensive soil contamination over several decades, posing serious health risks to humans through bioaccumulation in plants and subsequent transfer via the food chain. Due to the durability of PFOA in soil and its propensity to migrate and accumulate in plants, phytoremediation has been recognized as an effective remediation method. However, the phytotoxicity of PFOA and the adsorption of PFOA by soil hindered the efficiency of traditional phytoremediation. Therefore, this research employed plant growth-promoting rhizobacteria (PGPR)-assisted phytoremediation, augmented with the bio-stimulant fulvic acid (FA), to devise an effective soil remediation strategy tailored for PFOA contamination removal. The results indicated that Rhizobium sp. strain ZY2, endowed with PGP traits, significantly increased the root weight and shoot weight of pak choi by 194.67 % and 37.38 %, respectively, versus the non-inoculation treatment. Furthermore, inoculation with strain ZY2 enhanced soil alkaline phosphatase, protease, and cellulase activities, bolstering soil nutrient cycling and resource availability. On the other hand, compared to treatment with strain ZY2 alone, additional exogenous FA drastically reduced the residual fraction of PFOA in soil from 34.1 % to 1.9 %, likely mediated by complex electrostatic and hydrophobic interactions between FA and soil components. Ultimately, FA addition increased PFOA concentration in pak choi by 8.1-fold. Furthermore, FA could increase the relative abundance of beneficial rhizosphere bacteria (Actinobacterota and Methylotener, etc.), thereby creating a more favorable microenvironment for plant growth. In conclusion, the combined use of strain ZY2 and FA in phytoremediation notably strengthened plant resilience to PFOA, minimized soil sorption, and achieved high remediation efficacy, offering an effective system to mitigate PFOA-soil pollution's environmental and health risks. © 2024 Elsevier B.V.
