Title : Silicon nano-Biostimulants alleviate cadmium toxicity in bayberry (Myrica rubra) by modulating rhizosphere soil metabolites and microbial community
Abstract:
Chinese bayberry (Myrica rubra), a cultivated fruit crop in southern China for over 7000 years, is rich in phytochemicals with antioxidant, anti-tumor, and anti-diabetic activities. Heavy metals, including cadmium (Cd), pose a global threat to agricultural crops and human health. Physicochemical methods for Cd remediation often involve toxic compounds that harm the soil ecosystem. Nano-enabled techniques provide a sustainable platform for heavy metals remediation and enhancing crop resilience. Here, we investigated the potential of biologically synthesized (bio)-SiNPs in effectively alleviating Cd toxicity in bayberry plants by modulating biochemical properties, soil metabolites and microbiome. Bio-SiNPs are synthesized by cell-free cultural filtrate of a rice rhizosphere bacterial strain Chryseobacterium sp. strain RTN3 and are found spherical in shape with a size range of 15–47 nm. The Soil application of 250 mg kg⁻¹ bio-SiNPs improved antioxidant enzymes (ascorbate peroxidase +42.4%, peroxidase +41.2%, superoxide dismutase +35.3%), photosynthesis, and nutritional efficiency (N, P, Si, Fe, K+, Ca²⁺) of bayberry plants, while reducing acropetal Cd translocation by 42.3%. The 16S rRNA metagenome sequencing revealed that bio-SiNPs reshaped the bacterial community (Proteobacteria, Chloroflexi, Actinobacteriota, and Acidobacteriota). GC-MS based soil metabolomic analysis showed altered metabolite profiles involving amino acid, fatty acid, and sugar metabolic pathways, suggesting perturbed C and N metabolism consistent with bacterial community structure results. Overall, our findings demonstrate that bio-nanoremediation is a highly efficient and sustainable approach to enhance food production and security.
