and farming practices drive arbuscular mycorrhizal fungal communities in French vineyards.

Background: Nature-based management of vineyards is at the heart of a sustainable development for the next decades. Although much is known about grapevine benefits from Arbuscular Mycorrhizal Fungi (AMF), little is known about the influence of vineyard and farming practices on AMF communities.

Methods: We examined the relative effect of wine and agricultural practices (organic, conversion, and conventional) on AMF abundance and diversity across 75 vineyards distributed over 14 wine in 6 winegrowing regions in France. We estimate AMF abundance by measuring spore density and root mycorrhization rates, and characterize AMF communities composition using metabarcoding by sampling both root and spore compartments for each vineyard.

Results: Organic farming slightly increases AMF abundance (spore density and mycorrhization rate). Vineyards under conversion and using organic practices display a higher AMF diversity than conventional ones. vary widely in terms of AMF abundance and diversity, with the median of OTUs count per sample ranging from 9 () to 35 (). The composition of AMF communities is structured mainly by and in a lesser extent by practice. The effect of on AMF communities is partially explained by distance decay and soil properties, but the majority of variation is still explained only by the identity. Organic practices improve both abundance and diversity of AMF in vineyards, possibly leading to more productivity and resilience of grapevines.

Conclusion: This large-scale study highlights the importance of in our understanding of vineyard microbiome and paves the way to incorporation of AMF in microbial studies and applications.