Metagenomic analysis of rhizosphere soil microbial community functional characteristics and heavy metal remediation mechanisms of King grass inoculated with Serratia marcescens S27 under Cd-Cr co-contamination
Phytomicrobial remediation offers a sustainable solution for cadmium (Cd) and chromium (Cr) co-contaminated soils, but the regulatory mechanisms of microbiome-mediated phytoremediation enhancement remain elusive. We established a Serratia marcescens S27-king grass system to decipher synergistic mechanisms via multi-omics and spectral analyses. S27 significantly increased plant biomass (shoots: +95.2%; roots: +124.3%) and stem metal accumulation (Cd: +38.8%; Cr: +60.2%, P < 0.05). Metagenomics revealed S27 enriched keystone taxa (Pseudomonadota, Acidobacteria) and TCA cycle genes (sucC, sucD), with high-frequency horizontal gene transfer (HGT) (sucC: 88.5%; sucD: 69.4%) mediated by mobile genetic elements. RT-qPCR validated upregulated sucC/sucD expression and enzyme activity.