Association between Grape Yeast Communities and the Vineyard Ecosystems

Abstract

The grape yeast biota from several wine-producing areas, with distinct soil types and grapevine training systems, was assessed on five islands of Azores Archipelago, and differences in yeast communities composition associated with the geographic origin of the grapes were explored. Fifty-seven grape samples belonging to the Vitis vinifera grapevine cultivars Verdelho dos Açores (Verdelho), Arinto da Terceira (Arinto) and Terrantez do Pico (Terrantez) were collected in two consecutive years and 40 spontaneous fermentations were achieved. A total of 1710 yeast isolates were obtained from freshly crushed grapes and 1200 from final stage of fermentations. Twenty-eight species were identified, Hanseniaspura uvarum, Pichia terricola and Metschnikowia pulcherrima being the three most representative species isolated. Candida carpophila was encountered for the first time as an inhabitant of grape or wine-associated environments. In both sampling years, a higher proportion of H. uvarum in fresh grapes from Verdelho cultivar was observed, in comparison with Arinto cultivar. Qualitatively significant differences were found among yeast communities from several locations on five islands of the Archipelago, particularly in locations with distinctive agro-ecological compositions. Our results are in agreement with the statement that grape-associated microbial biogeography is non-randomly associated with interactions of climate, soil, cultivar, and vine training systems in vineyard ecosystems. Our observations strongly support a possible linkage between grape yeast and wine typicality, reinforcing the statement that different viticultural terroirs harbor distinctive yeast biota, in particular in vineyards with very distinctive environmental conditions.

Fig 1. Combinations of soil type and grapevine training system in the sampled vineyards.

A: not- trellised grapevine (NT) in soil covered with stones (SS); B: NT in solidified lava flows (SL); C: NT in arable soil (AS); D: trellised grapevines (TG) in AS.

Fig 2

Sampling sites (A) and summary of the samples collected (B) in 2009 and 2010 in 22 vineyards from 13 wine-producing areas on five islands of the Azores Archipelago, from the grapevine cultivars Verdelho dos Açores (Ver), Arinto da Terceira (Ar) e Terrantez do Pico (Tr) planted in arable soil (AS), soil covered with stone (SS) or solidified lava flows (LF), and trained as trellised grapevines (TG), non-trellised grapevines (NT) or lying grapevines (LG).

Fig 3

Yeast communities composition (in percentage) from freshly crushed grapes of the grapevine cultivars Verdelho dos Açores (Ver) and Arinto da Terceira (Ar) collected in 2009 and 2010 on A) all sampled locations, B) in Lajidos (PLJ), the remaining locations of Pico (PRL), in Biscoitos (BCT) and in Graciosa (GRC) and C) in six vineyard (numbers 5, 12, 15, 16, 17 and 19; see Table 1).

Fig 4. Analysis of similarity (ANOSIM) on square root transformed species incidences, using the software PAST [55].

Statistically significant differences in yeast community composition observed between islands/locations (SMG: São Miguel, BCT: Biscoitos, GRC: Graciosa, PLJ: Lajidos, PRL: remaining locations in Pico, SJG: São Jorge). R-values are indicated in bold, and P-values in italic. Light grey and dark grey boxes refer to comparisons made with yeast species obtained in 2009 and 2010, respectively.