A novel nano-fungicide for Botrytis cinerea control: in planta efficacy and mechanistic insights of silver nanoparticles on a thiolated dendritic mesoporous silica framework

Pathogenic fungi such as Botrytis cinerea ( B. cinerea ) present a major challenge to sustainable agriculture. In this study, we report the design and synthesis of a novel thiol-functionalized dendritic mesoporous silica-based nano-fungicide (Ag@DMSNs-SH), featuring ultrasmall silver nanoparticles (AgNPs) uniformly generated and immobilized in situ within the thiolated silica framework. This innovative synthesis strategy ensures homogeneous AgNPs dispersion, enhanced stability, and a sustained silver release profile. Ag@DMSNs-SH demonstrated superior, dose-dependent antifungal activity against B. cinerea compared to free AgNPs. At 1.5 mg/mL, it achieved 78.63% mycelial growth inhibition over six days, significantly outperforming free AgNPs (15.57% inhibition, P  < 0.05). Mechanistic studies revealed that Ag@DMSNs-SH disrupts the fungal cell membrane, causing cytoplasmic leakage. In detached strawberry leaf assays, Ag@DMSNs-SH demonstrated a high curative efficacy, suppressing disease by 92.27% at the minimum inhibitory concentration (MIC), compared to 36.64% for free AgNPs. Its high antifungal performance was further confirmed in potted plant and field trials, where Ag@DMSNs-SH reduced disease incidence from 92.78% to 26.11% and from 83.30% to 19.79%, respectively. These results establish Ag@DMSNs-SH as a new generation of sustained-release nano-fungicide with strong potential for the management of fungal diseases in high-value crops.