Bacteria associated to plants naturally selected in a historical PCB polluted soil show potential to sustain natural attenuation

The phylogenetic diversity of the bacterial communities associated to three spontaneous plant species (Medicago sativa, Centaurea nigrescens and Dactilys glomerata) naturally established in a former agricultural field located within the heavily polluted SIN (National Priority Sites) site Caffaro in north Italy have been studied. The site is highly contaminated by chlorinated persistent organic pollutants, mainly constituted by polychlorobyphenils (PCBs), together with heavy metals and metalloids, in variable concentrations and uneven distribution. We used high-throughput sequencing techniques to investigate the bacterial community naturally associated to the rhizosphere and the root surrounding soil of the three plant species. The bacterial communities in the root-associated soil fractions have been compared with that of the unvegetated soil (bulk soil).