Biodiversity of the mycobiota associated with the surface of Malbec grapes from the Southern Oasis of Mendoza (Argentina) viticulture region approached by high-throughput sequencing

GARAU, J.; MERÍN, M.G.; PRENDES, L.P.; SEVILLANO, M.E.; MARTÍN, M.C.; RUIZ-LARREA, F.; MORATA, V.I.

Mendoza

Congreso; 15th International Terroir Congress; 2024

Catena Institute, FCA-UNCUYO, IBAM-CONICET-UNCUYO, Gobierno de Mendoza

The use of high-throughput sequencing (HTS) technologies is a powerful tool to study the microbial communities of an ecosystem and to explain how the environment influences the composition of microorganisms present in such an ecosystem. This work aimed at characterising the fungal biodiversity on the surface of Malbec grapes from four subregions of the Southern Oasis of Mendoza viticulture region. Fungal biodiversity was studied by mass sequencing of ITS2 amplicons from DNA samples obtained by washing the surface of intact Malbec grapes collected during the 2023 vintage from vineyards located in four subregions of the Southern Oasis of Mendoza (Rama Caída, Las Paredes, Villa Atuel and Cuadro Nacional). The DNA extraction method was optimised using the DNeasy PowerSoil Pro kit (QIAGEN). DNA extraction and concentration were verified by agarose gel electrophoresis. The ITS2 region of the fungal genome was amplified using primers FITS7 and ITS4. Sequencing was performed on an Illumina MiSeq ultra-sequencer at the Genomics and Bioinformatics Platform of the Centro de Investigación Biomédica de La Rioja (CIBIR), in Logroño (Spain). The bioinformatic analysis was performed using the QUIIME2 software. In all the subregions studied, there was a predominance of fungi belonging to the subdivision of the kingdom Fungi Ascomycota, with relative abundances ranging from 86.06 to 99.49%, with Dothideomycetes as the predominant class. The most abundant genera and species were Aureobasidium thailandense (16.48 to 61.23%), Cladosporium herbarum (4.33 to 50.27%), and Curvularia spp. (23.92 to 35.28%) for all subregions. No significant differences in alpha diversity were observed between the subregions analysed in any of the calculated indices. According to the beta diversity indices, significant differences in fungal taxa were observed between the subregions, suggesting the existence of different fungal microbiomes in the terroir studied.