Shifting Fungal Networks: How Dactylonectria macrodidyma Shapes Grapevine Mycobiome in Diverse Soils

This study investigates the impact of Dactylonectria macrodidyma on fungal community dynamics in grapevines grown in sandy and clay soils, highlighting how soil properties influence pathogen-induced changes in fungal community structure. High-throughput sequencing and microbial network analyses revealed that D. macrodidyma significantly reduces fungal diversity in root microbiomes, with the effect being more pronounced in sandy soils at later time points. Under experimental greenhouse conditions, the inoculation of potted grapevine plants with D. macrodidyma resulted in notable shifts in the fungal community composition, including the displacement of beneficial taxa such as Clonostachys and Trichoderma, and the promotion of pathogenic genera including Ilyonectria and Botrytis. SparCC network analysis indicated that D. macrodidyma increased competitive interactions in sandy soil, while fostering cooperative pathogenic networks in clay soil, reflecting distinct soil-dependent microbial responses. Additionally, functional guild prediction revealed a shift toward pathogenic dominance, with declines in symbiotrophic and saprotrophic fungi, suggesting potential consequences for nutrient cycling and microbial stability. These findings underscore the need for soil-specific disease management strategies in viticulture to preserve microbial diversity and suppress pathogen proliferation. This study provides critical insights into the ecological impact of D. macrodidyma on grapevine microbiomes, informing the development of targeted interventions to enhance plant health and sustainability in viticulture.