Insight into the mechanisms of plant growth promoting strain ZY2 in improving phytoremediation efficiency in perfluorooctanoic acid (PFOA)-contaminated soil

Abstract

Perfluorooctanoic acid (PFOA) is an anthropogenic perfluorinated alkyl substance which can enter the food chain and pose health risks. The hydrophilic carboxyl head of PFOA enhances its solubility in water, making it easier for PFOA to migrate with soil water and be absorbed by plants from the soil. Plant growth promoting bacteria (PGPR) have the ability to compensate for plant growth disadvantage under unfavorable conditions and are therefore likely to reduce the negative effects of PFOA phytotoxicity on plant growth. However, the effectiveness of the PGPR-assisted plant systems for remediation of PFOA-contaminated soil has not yet been demonstrated. To this end, a novel strain of Rhizobium sp. was isolated and named as ZY2, which is tolerant to PFOA and exhibits significant plant growth-promoting trains. The results indicated that inoculation with strain ZY2 significantly increased the biomass of oilseed rape. Notably, the accumulation content of PFOA in oilseed rape roots increased significantly by 89.0 % and the removal of PFOA from the soil increased over 3 times after inoculation with ZY2. In addition, inoculated ZY2 also altered the rhizosphere soil bacterial community structure which might correlate with the production of a series of hydrolases and reductases involved in soil carbon and nitrogen cycling processes. Generally, this study offered a novel approach for establishing an effective phytoremediation system in PFOA-contaminated soil.