Recent progress on the microbial mitigation of heavy metal stress in soybean: overview and implications

Abstract

Plants are adapted to defend themselves through programming, reprogramming, and stress tolerance against numerous environmental stresses, including heavy metal toxicity. Heavy metal stress is a kind of abiotic stress that continuously reduces various crops’ productivity, including soybeans. Beneficial microbes play an essential role in improving plant productivity as well as mitigating abiotic stress. The simultaneous effect of abiotic stress from heavy metals on soybeans is rarely explored. Moreover, reducing metal contamination in soybean seeds through a sustainable approach is extremely needed. The present article describes the initiation of heavy metal tolerance mediated by plant inoculation with endophytes and plant growth-promoting rhizobacteria, the identification of plant transduction pathways via sensing annotation, and contemporary changes from molecular to genomics. The results suggest that the inoculation of beneficial microbes plays a significant role in rescuing soybeans under heavy metal stress. They create a dynamic, complex interaction with plants via a cascade called plant–microbial interaction. It enhances stress metal tolerance via the production of phytohormones, gene expression, and secondary metabolites. Overall, microbial inoculation is essential in mediating plant protection responses to heavy metal stress produced by a fluctuating climate.

Rhizobium symbiosis improves amino acid and secondary metabolite biosynthesis of tungsten-stressed soybean (Glycine max)

“…Rhizobacteria are known to influence plant growth and stress resistance via various mechanisms. Inoculation with so-called plant-growth-promoting rhizobacteria (PGPR) has been shown to increase the production of various primary and secondary metabolites, induce systemic resistance, enhance the bio-availability of plant nutrients as well as immobilize heavy metal ions ( Shameer and Prasad, 2018 ; Shaffique et al., 2023 ). Rather recently, actinobacteria have also been shown to alleviate the phytotoxicity of tungsten nanoparticles on legumes ( Selim et al., 2021 ).…”