Vicia sativa–rhizospheric bacteria interactions to improve phenol remediation

The aim of this study was to evaluate whether the interaction of Vicia sativa with a bacterial strain capable of using phenol as sole carbon and energy sources can moderate adverse effects of this pollutant in plant tissues. A bacterial strain identified as Bacillus sp., isolated from a heavily polluted environment, was inoculated at different stages of growth. In root elongation assay, inoculated seeds showed higher values of relative root elongation and germination index than uninoculated ones in the presence of high phenol concentrations. Thus, common vetch–Bacillus sp. association could be important at the first stages of development allowing this plant to grow in highly polluted environments. Besides, phenol removal was largely accelerated in phenol-spiked soils, after 48 h of treatment with uninoculated/inoculated plants rather than by adsorption or biodegradation of the bacterial strain. Peroxidase and ascorbate peroxidase activities increased significantly in uninoculated plants, while superoxide dismutase activity, chlorophyll, malondialdehyde, and H2O2 levels of aerial parts remained unaltered in uninoculated/ inoculated plants treated with the pollutant, demonstrating that the efficient response to oxidative damage did not depend on the inoculation.