Macrowine 2021
IVES 9 IVES Conference Series 9 Changes in grape-associated microbiome as a consequence of post-harvest withering

Changes in grape-associated microbiome as a consequence of post-harvest withering

Abstract

AIM: Grape withering is an oenological post-harvest process used for production of reinforced and sweet wines. Drying can be carried out by keeping the ripe grape in traditional large, well-aired rooms (non-controlled environment) or, more and more often, in a warehouse under controlled conditions of airflow and relative humidity (controlled environment)[1]. The microbiome associated with withering grapes has been showed to be profoundly linked with the process and its results[2,3]. The main aims of this study were to (a) provide detailed information on bacterial and fungal communities evolution throughout the grapes withering process, and (b) perform a comparative study between two dehydration methods, regarding the associated microbiomes.

METHODS: Samples of withering grapes were collected in the Italian viticultural zone Valpolicella, where the renowned wine Amarone is produced using non-botrytized withered grapes of Corvina variety. Two different post-harvest conditions were analyzed (non-controlled and controlled withering environment); grapes coming from two vineyards (close but differing for soil characteristics) were considered, during 2 subsequent vintages. To map the microbiome during withering, Next-Generation Sequencing (NGS) was employed[4]: the progression of fungal and bacterial species was characterized through metabarcoding (ITS and 16s) at 4 different time points (from 0 to 30% of weight loss).

RESULTS: No significant differences, at biodiversity level, were found between the microbial communities of grapes from the two vineyards, nor between the two vintages. The evolution of microorganisms during drying was instead interestingly variable. Moreover, slight but significant differences were found between the two withering systems, although significant only for some taxa.

CONCLUSIONS: NGS metabarcoding showed to be an effective technique in the study of withering-grape microbiome and provided new information on the changes occurring in microbial communities because of the drying process. Indeed, to our knowledge, the present work is the first time-course study of both mycobiome and bacteriome throughout withering. The study also showed that changes of drying conditions can lead to significant modifications of the berry-skin microbiota.

DOI:

Publication date: September 3, 2021

Issue: Macrowine 2021

Type: Article

Authors

Tiziana Nardi, Luca Nerva*, Walter Chitarra*

CREA – Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria, Centro di Ricerca Viticoltura ed Enologia, Conegliano, Italy, Diego Tomasi and Tiziana Nardi  CREA – Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria, Centro di Ricerca Viticoltura ed Enologia, Conegliano, Italy *these authors contributed equally to the work

Contact the author

Keywords

Post-harvest, grape microbiome, metabarcoding, epiphytes

Citation

Related articles…

Impact of microclimate on berry quality parameters of white Riesling (Vitis vinifera L.)

Knowledge has been accumulated on the impact of microclimate, in particular berry temperature and irradiation, for a wide range of red varieties. However, little research has been dedicated on the effects of the same factors on the quality of white grape varieties.

Genotypic variability in root architectural traits and putative implications for water uptake in grafted grapevine

Root system architecture (RSA) is important for soil exploration and edaphic resources acquisition by the plant, and thus contributes largely to its productivity and adaptation to environmental stresses, particularly soil water deficit. In grafted grapevine, while the degree of drought tolerance induced by the rootstock has been well documented in the vineyard, information about the underlying physiological processes, particularly at the root level, is scarce, due to the inherent difficulties in observing large root systems in situ. The objectives of this study were to determine genetic differences in the root architectural traits and their relationships to water uptake in two Vitis rootstocks genotypes (RGM, 140Ru) differing in their adaptation to drought. Young rootstocks grafted upon the Riesling variety were transplanted into cylindrical tubes and in 2D rhizotrons under two conditions, well watered and moderate water stress. Root traits were analyzed by digital imaging and the amount of transpired water was measured gravimetrically twice a week. Root phenotyping after 30 days reveal substantial variation in RSA traits between genotypes despite similar total root mass; the drought-tolerant 140Ru showed higher root length density in the deep layer, while the drought-sensitive RGM was characterised by shallow-angled root system development with more basal roots and a larger proportion of fine roots in the upper half of the tube. Water deficit affected canopy size and shoot mass to a greater extent than root development and architectural-related traits for both 140Ru and RGM, suggesting vertical distribution of roots was controlled by genotype rather than plasticity to soil water regime. The deeper root system of 140Ru as compared to RGM correlated with greater daily water uptake and sustained stomata opening under water-limited conditions but had little effect on above-ground growth. Our results highlight that grapevine rootstocks have constitutively distinct RSA phenotypes and that, in the context of climate change, those that develop an extensive root network at depth may provide a desirable advantage to the plant in coping with reduced water resources.

Stomatal behaviour of three minority grapevine varieties grown in the La Mancha region (Spain)

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.19.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...

A few observations on double sigmoid fruit growth

Many fleshy fruit, including the grape berry, exhibit a double‐sigmoid growth (DSG) pattern. Identification of the curious DSG habit has long been attributed to Connors’ (1919) work with peaches

Cover crop influence on water relations, yield, grape and wine composition of Pinot noir

The effect of cover crop on the water relations, yield and grape composition of Pinot noir vines was investigated during two seasons (2003 and 2004) in a gravely soil located in Tarragona (Spain). Seventeen-year-old vines, grafted onto R110 and trained onto a Ballerina training system, were used.