Brassica juncea can improve selenite and selenate abatement in selenium contaminated soils through the aid of its rhizospheric bacterial population

Brassica juncea was grown in a soil spiked with selenium oxyanions (selenite and selenate) in order to verify the contribution of both plants and rhizospheric bacteria to the abatement of soluble forms of the metalloid. A mass balance of selenium was calculated in pots and the different chemical species of this contaminant were measured. Evidence gained suggests that selenium oxyanions were reduced into less bioavailable forms thank to a marked contribution of the soil bacterial population. Rhizobacteria resulted particularly elicited by the presence of B. juncea which directly participated in selenium decontamination through either phytoextraction or putative volatilisation. Moreover, these microbes colonizing B. juncea root system were monitored by both culture dependent and culture independent methods (i.e. DGGE analysis). Finally, bacterial isolates were tested in vitro for their resistance to selenium oxyanions.