Influence of soil physical and chemical properties on fungal and bacterial communities in 12 vineyard soils from northern Italy

Soil chemical and physical properties, which are determined both by pedo-climatic factors and by management, can significantly influence microbial communities. In this work, soil samples were collected in 12 vineyards located in two neighbouring groups of hills, both renowned in Italy for their wines: the Euganean Hills, which are of volcanic origin, mainly trachyte and riolite soils, and the Berici Hills, with a marine sedimentary genesis, mainly clay-limestone soil. Soil bacterial and fungal communities were determined through 16S and ITS by 454 pyrosequencing analysis, and their relative taxa abundances were calculated. Taxa abundances were also correlated with soil characteristics, to assess whether given features can specifically influence defined microbial taxa in this kind of anthropogenic environment. In order of abundance, the dominant bacterial taxonomic groups across all samples were: Actinobacteria, Alphaproteobacteria, Acidobacteria, Bacteroidetes, Betaproteobacteria, Chloroflexi, Gemmatimonadetes, Planctomycetes, Deltaproteobacteria, Gammaproteobacteria. Among fungal phyla, Ascomycota largely dominated followed by Basidiomycota. Among these phyla, prevailing fungal classes were Dothideomycetes, Sordariomycetes, Agaromycetes, Leotiomycetes, Eurotiomycetes and Tremellomycetes. Some of these taxa and the less abundant microbial groups were found to be significantly influenced by soil pH and texture. Moreover, a considerable number of significant correlations were found between the relative abundance of microbial taxa and the amount of several different chemical parameters such as: total carbon, nitrogen, phosphorus, exchangeable bases and microelements. These analyses provided novel insights into how soil structure and management can affect soil microbial community composition.