Mitigation of GenX Transfer to Brown Rice ( Oryza sativa L.) by Phosphorus Management and Phosphate-Solubilizing Bacteria: Hydroponic Screening and Flooded-Soil Validation

Abstract

GenX is a mobile replacement PFAS that can enter edible rice tissues through soil-water-plant transfer. This study combined hydroponic screening with flooded-soil pot validation to evaluate whether phosphorus (P) sources and phosphate-solubilizing bacteria (PSB) reduce GenX phytotoxicity and grain loading in rice. In hydroponics, inorganic phosphate (Pi) provided stronger growth protection than organic P (OP), while PSB effects varied with P form and exposure level. Pi+PSB increased seedling biomass by up to 117.9% under the highest GenX exposure and reduced oxidative damage and GenX translocation. In flooded soil, CK+PSB, OP+PSB, and Pi+PSB reduced brown-rice GenX concentrations by 47.9%, 56.7%, and 61.2%, respectively, relative to CK+GenX; corresponding grain mass burdens declined by approximately 46.2%, 52.5%, and 55.0%. Root transcriptomic analysis revealed responses associated with glutathione-centered redox protection, sulfur metabolism, H2O2 catabolism, and cell-wall defense. Together, P management and PSB inoculation offer complementary approaches to reduce GenX transfer to rice grains.