Synergistic Recruitment of Symbiotic Fungi by Potting and Scleroderma bovista Inoculation Suppresses Pathogens in Hazel Rhizosphere Microbiomes

This study explored how potted treatments (with and without <i>Scleroderma bovista</i> inoculation) shape rhizosphere microbial diversity in hazel across five soils using split-root cultivation. Three treatments (control, split-root, split-root with <i>S. bovista</i>) were analyzed for root growth and microbial dynamics. <i>S. bovista</i> inoculation consistently enhanced root parameters (number, tips) in all soils. Potted treatments (with and without <i>S. bovista</i> inoculation) altered microbial features (OTU/ASV), with only 0.9-3.3% of features remaining unchanged. At the class level, potting increased <i>Agaricomycetes</i> abundance while reducing <i>Sordariomycetes</i>, a trend amplified by <i>S. bovista</i>. Potting decreased species richness estimates (ACE and Chao1), while both treatments lowered diversity index (Shannon index). Potted treatments without <i>S. bovista</i> inoculation drove stronger shifts in species composition than inoculation. Findings reveal potting and <i>S. bovista</i> synergistically recruit symbiotic fungi via root exudates, establishing disease-suppressive communities that selectively inhibit pathotrophic fungi (particularly plant pathogen <i>Coniothyrium</i> and fungal parasite <i>Cladobotryum</i>) while roughly maintaining non-pathogenic saprotrophic microbes essential for organic matter decomposition. This work provides insights for optimizing hazel orchard management and ectomycorrhizal agent development.