A microbiome survey of Tokaj highlights viticultural terroirs in Mád and suggests soil microbial contribution to must polyphenol contents

Abstract A Hungarian survey of Tokaj-Mád vineyards was conducted. Shot-gun metabarcoding was applied to decipher the microbial-terroir. The results of 60 soil samples showed that there were three dominant fungal phyla, Ascomycota 66.36% ± 15.26, Basidiomycota 18.78% ± 14.90, Mucoromycota 11.89% ± 8.99, representing 97% operational taxonomic units (OTUs). Mutual interactions between microbiota diversity and soil physicochemical parameters were revealed. Principal component analysis showed descriptive clustering patterns of microbial taxonomy and resistance gene profiles in the case of the four historic vineyards (Szent Tamás, Király, Betsek, Nyúlászó). Soil seed bacteria changed markedly due to ripening. Network analyses were performed to unravel changes in fungal interactions when comparing postveraison and preharvest samples. In addition to the arbuscular mycorrhiza Glomeraceae , the families Mycosphaerellacae and Rhyzopodaceae and the class Agaricomycetes were found to have important roles in maintaining soil microbial community resilience. By investigating the possible connections between the soil fungal community and the associated must samples, it was found that the species of the Diversispora genus and the family Cordycipitaceae were shown to be good soil indicator microorganisms of a high must polyphenol content. Functional metagenomics showed that the soil Na content stimulated several of the microbiota-related agrobiogeochemical cycles, such as nitrogen and sulphur metabolism; steroid, bisphenol, toluene, dioxin and atrazine degradation and the synthesis of folate.