Iron oxide nanoparticles as enhancers of growth-promoting bacteria: a step towards developing nano-biofertilizers

Abstract

Using plant growth-promoting bacteria (PGPB) as biopesticides and biofertilizers is becoming an increasingly popular sustainable practice. However, there are significant limitations associated with these practices, which can be minimized through nanotechnology. This study aims to evaluate the efficiency of iron oxide nanoparticles (IONPs) in improving the efficacy of PGPB in soybeans. We assessed the physiological and biochemical parameters in soybean seedlings treated with different combinations of PGPB and IONPs. Our results showed that adding IONPs to soybean seed improves seed vigor and early seedling development, suggesting a synergy between IONPs and PGPB. The seed vigor percentage in the treatment IONP 300 mg kg⁻¹ + PGPB was 45% higher than that in IONP 300 mg kg⁻¹ − PGPB. The addition of IONP also improve the root length in 98%. The absence of lipid peroxidation indicates no damage to the cell membrane with the addition of IONPs. Furthermore, the low modulation of the enzymatic antioxidant system highlights the non-oxidative pattern of the treatment. This synergy between IONPs, PGPB, and soybean plants could result from the action of iron in improving the physiological functions of both the plant and the bacteria.