The microbial terroir of Agiorgitiko cv. in the Nemea PDO zone

Agiorgitiko is a major Greek red winegrape variety of high economic importance cultivated almost exclusively in the Nemea PDO zone in Peloponnese, Greece. Here, we describe the microbiota and mycobiota of grape and soil samples collected over three consecutive harvest periods (September 2019, 2020 and 2021). The results revealed a common microbiome composition across the Nemea PDO zone vineyards, despite significant variations in the community structure regarding dominant bacterial and fungal taxa per sampling year, which were associated with weather factors. Grape samples of 2019 were enriched in several plant growth promoting bacteria, including Bradyrhizobium, Streptomyces, Massilia and Sphingomonas, selected by the particular weather conditions. On the other hand, the predominance of Botrytis in the same samples was observed, indicating again the impact of weather conditions on the microbial structure. Understanding these dynamics could improve management practices aimed at vine cultivation and wine quality.