Microbe-EDTA mediated approach in the phytoremediation of lead-contaminated soils using maize (Zea mays L.) plants

Abstract

In the current study, we investigated the potential of Cronobacter sakazakii- ethylenediaminetetraacetic acid (EDTA) assisted phytoremediation potential of Zea mays L. to remediate lead (Pb)-contaminated soils. The C. sakazakii exhibited various stress tolerance mechanisms via plant growth promoting (PGP) traits, intrinsic extracellular enzyme production and antibiotic resistance. A greenhouse experiment was conducted to examine the dual effects of plant growth promoting endophytic bacteria (PGPEB)-chelator synergy in maize plants under different Pb contaminated soil regimes. C. sakazaii-EDTA (5 mM EDTA kg⁻¹) complex significantly (p < 0.05) enhanced plant growth and biomass (48.91%); chlorophyll a, b and carotenoid contents (27.26%, 25.02% and 42.09%); relative water content (61.33%); proline content (63.60%); root and shoot Pb accumulation capacity (52.31% and 44.71%) in Pb contaminated soils. This may suggest the efficacy of current approach in enhancing plant tolerance capability toward Pb-uptake and phytoremediation capacity. Moreover, maize plants showed differential response to Pb availability in soil-1 (S1; Pb spiked soil, 500 mg kg⁻¹) and soil-2 (S2; aged-contaminated soil) under various treatments. We describe the intriguing role of C. sakazakii-EDTA-maize system for Pb decontamination which can be used as a base line to explore the proposed combinatorial approach for long-term trails under field conditions for reclamation of Pb-contaminated soils.

Highlights

• The PGPEB-EDTA mediated potential of Z. mays against Pb spiked and industrial contaminated soils is noticed.

• Increased tolerance of Z. mays against Pb in association with C. sakazakii, and EDTA is reported first time.

• Enhanced accumulation of metals by Z. mays is reported under combined treatment of C. sakazakii, and EDTA.

• Inoculation of plants with C. sakazakii, and EDTA has positive effects on growth and accumulation of Pb by Z. mays.

Keywords:

• Bioconcentration factor
• C. sakazakii
• contamination
• heavy metals
• Z. mays

Disclosure statement

The authors declare that they have no competing interests