Recombinant protein, AlnA, combined with transgenic alfalfa remediates polychlorinated biphenyl-contaminated soils: efficiency and rhizosphere microbial community response.

OBJECTIVE: To investigate the remediation efficiency of polychlorinated biphenyl (PCB)-contaminated soils by the combination of a bioemulsifying protein, AlnA, and alfalfa expressing bphC. RESULT: The combination of AlnA and transgenic alfalfa promoted PCB soil remediation through the pot experiments. The removal rates of tri-PCBs (PCB 16/PCB 32 and PCB 31/PCB 28) and tetra-PCB (PCB 49) in transgenic alfalfa/AlnA treatment were 3.6-, 1.1-, and 2-fold higher than in transgenic alfalfa treatment alone. Analysis of gene copy number revealed that the PCB-degrading gene, bphC, of Pseudomonas-like bacterial populations in transgenic alfalfa/AlnA treatment increased 1.5-fold compared with that of unplanted soils. Bacterial community Illumina sequencing showed Pseudomonas, Arthrobacter, and Sphingomonas positively correlated with the removal rates of PCBs.
CONCLUSIONS: PCB removal was unrelated to bacterial community diversity but positively correlated with their specific degraders and bphC gene expression.