Investigation on microbial community in remediation of lead-contaminated soil by Trifolium repensL.

Abstract

Trifolium repensL. is a plant with strong adaptability and large biomass, which possess great potential for phytoremediation. However, little is known concerning its remediation effects and changes in rhizosphere microbial activity and community structure under heavy metal pressure. The aims of this study were to evaluate lead accumulation of Trifolium repensL., study microbial lead resistance, metabolism and community structure characteristics in rhizosphere soils. The accumulated Pb concentration of Trifolium repensL. was observed in 100 and 500 mg/kg Pb contained soil at 55.81 and 90.3 mg/kg, respectively, which cause the decrease of acid-soluble fractions in rhizosphere soil. In the progress of lead-contaminated soil phytoremediation by Trifolium repensL., Pb resistance and metabolic activities of microorganisms have been prompted gradually. In addition, the microbial community composition and abundance were investigated using Illumina sequencing and quantitative PCR. The result showed that after phytoremediation, beneficial microorganisms, such as Flavisolibacter, Kaistobacter, and Pseudomonas, increased, becoming the dominant genera. This study has provided insight into the distribution and activity of the microbial community.