Bacterial endophytes enhance phytostabilization in soils contaminated with uranium and lead

ABSTRACT

The combined use of plants and bacteria is a promising approach for the remediation of polluted soil. In the current study, the potential of bacterial endophytes in partnership with Leptochloa fusca (L.) Kunth was evaluated for the remediation of uranium (U)- and lead (Pb)-contaminated soil. L. fusca was vegetated in contaminated soil and inoculated with three different endophytic bacterial strains, Pantoea stewartii ASI11, Enterobacter sp. HU38, and Microbacterium arborescens HU33, individually as well as in combination. The results showed that the L. fusca can grow in the contaminated soil. Bacterial inoculation improved plant growth and phytoremediation capacity: this manifested in the form of a 22–51% increase in root length, 25–62% increase in shoot height, 10–21% increase in chlorophyll content, and 17–59% more plant biomass in U- and Pb-contaminated soils as compared to plants without bacterial inoculation. Although L. fusca plants showed potential to accumulate U and Pb in their root and shoot on their own, bacterial consortia further enhanced metal uptake capacity by 53–88% for U and 58–97% for Pb. Our results indicate that the combination of L. fusca and endophytic bacterial consortia can effectively be used for the phytostabilization of both U- and Pb-contaminated soils.

KEYWORDS:

• Leptochloa fusca
• heavy metals
• radionuclides
• endophytic bacteria
• phytostabilization

Funding

The research was supported by the funded project from Higher Education Commission, Pakistan (grant number 20-3854/R&D/HEC/14) and the International Foundation of Science (IFS) Sweden and the Organisation for the Prohibition of Chemical Weapons (OPCW) (grant number W/5104-2).