Rhizosphere-associated microbiota of Canavalia ensiformis in sulfentrazone bioremediation

Abstract

The objective of this study was to determine the efficiency of the microbial rhizosphere (Canavalia ensiformis) in the phytoremediation of sulfentrazone using quantification methods (CO2 evolution, microbial biomass carbon, and metabolic quotient) and identification of bacteria (PCR-DGGE technique). The experiment was conducted in a completely randomized design, in a 2x4 factorial scheme, with four replications. The treatments were composed of rhizospheric soil (cultivated with C. ensiformis) and non-rhizosphere soil (uncultivated soil); and four levels of contamination by sulfentrazone (0, 200, 400, and 800 g ha⁻¹ a.i.). The microbiota associated with the rhizosphere of C. ensiformis efficiently reduced sulfentrazone residues in the soil, with better performance at the dose of 200 g ha⁻¹ a.i. Using the PCR-DGGE technique allowed the distinction of two profiles of bacteria in the rhizospheric activity of C. ensiformis. The second bacterial profile formed was more efficient in decontaminating soil contaminated with sulfentrazone residue. The microbiota associated with the rhizosphere of C. ensiformis has an efficient profile in decontaminating soils with residues equivalent to 200 g ha⁻¹ a.i. the herbicide sulfentrazone.

Graphic Abstract

NOVELTY STATEMENT

Phytoremediation of soils contaminated with herbicide residues is a viable technique for decontamination of the environment.

Canavalia ensiformis has an efficient profile in the decontamination of soils with residue equivalent to 200 g ha⁻¹ a.i. of the herbicide sulfentrazone.

The PCR technique and microbial respiration used to analyze the diversity and estimate the bacterial population of a soil are viable tools to evaluate the phytoremediation potential of the microbiota associated with plant species.

Keywords:

• Bacteria
• bioremediation
• green manures
• rhizodegradation

Acknowledgments

We are grateful to “Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)," “Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)” and “Fundação de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG)”.