Silver Nanoparticle Priming Enhanced Seed Germination in Bupleurum chinense and Reshaped the Fungal Community Structure, Reducing the Robustness of the Fungal Interaction

Seed germination represents the initial stage of the plant life cycle and directly affects subsequent plant establishment. Mold infestation is a major cause of reduced germination rate, yet effective and safe control methods are still lacking. Thus, developing effective strategies to ensure healthy seed germination is of critical importance. This study investigated the effect of priming with silver nanoparticles (AgNPs) on the germination rate of Bupleurum chinense seeds and on mold suppression. Additionally, we aimed to clarify the underlying microbial mechanism through high-throughput sequencing of the internal transcribed spacer (ITS) region. Seeds primed with 15 mg/L AgNPs exhibited a significantly increased germination rate of 71.67% (vs. 58.90% in control) and reduced mold incidence to 16.46% (vs. 31.01%). The ITS sequencing revealed that AgNPs significantly reduced the Shannon index to 3.60 (vs. 4.04) and decreased the abundance of potential pathogens. Co-occurrence network analysis demonstrated that AgNPs simplified the fungal network and reduced the natural connectivity to 22.35 (vs. 39.38). Topological analysis identified five keystone hub genera (e.g., Trichosporon, Podospora), whose suppression indicates their critical roles in network maintenance. This study provides evidence supporting the application of AgNPs in seed germination and offering a foundation for addressing germination challenges in mold-susceptible seeds.