Work

The cadmium-tolerant selenium-soluble strain Bacillus cereus LB2 drives selenium enrichment and cadmium reduction in rice by reshaping rhizosphere microbial communities and functions

Year: 2025

Type: article

Abstract: In regions rich in selenium (Se), the coexistence of Se and cadmium (Cd) in paddy soil presents risks to the safety of rice ( Oryza sativa L.) products. In this study, the Cd-tolerant Se-solubilizing bacterial strain Bacillus cereus LB2 was shown to solubilize mineral Se and adsorb Cd, potentially mediated by its extracellular metabolites derived from tryptophan and purine metabolic pathways. Pot experiments revealed that the inoculation of strain LB2 promoted rice growth in Se–Cd-rich soil. Compared with the control, inoculation with strain LB2 increased the grain Se content by 20–23 %, whereas the Cd content decreased by 18.33–36.6 %. The reassembly of the rhizosphere microbiome is an important mechanism for promoting Se enrichment and reducing Cd in rice. Stronger iron (Fe) respiration and sulfate respiration in the rhizosphere bacterial community promoted the transformation of oxides, increased the availability of Se by 13–36 %, and decreased the availability of Cd by 3–17.69 %. In addition, the abundance of purine metabolites was strongly correlated with bacterial abundance, which may be the key driving force through which strain LB2 can recruit functional microorganisms. This study provides a new perspective for the safe use of Se–Cd-rich soil. • Strain LB2 solubilizes Se and removes Cd through extracellular metabolites. • Strain LB2 promotes Se activation and Cd sequestration in soil. • Strain LB2 can promote Se enrichment and Cd reduction in rice in Se–Cd-rich soil. • Strain LB2 remodels the rhizosphere microbial community and functions through a deterministic assembly process. • Purines may be a key driving force by which strain LB2 reshapes the bacterial community structure.

Source: Environmental Chemistry and Ecotoxicology

DOI: 10.1016/j.enceco.2025.09.027