Sustainable management of grapevine trunk diseases

Mannoproteins are released at the end of alcoholic fermentation due to yeast autolysis [1]. It has been described a positive effect of these molecules on lactic acid bacteria growth [2]. The main objective of this work was the characterization of different mannoproteins extracted from active dry yeast (ADY) and the assessment of their effect on Oenococcus oeni and malolactic fermentation (MLF).

Granxa D’Outeiro is a recovered ancient vineyard located in the heart of DOP Ribeiro, where traditional white grapevine varieties are growing under sustainable management. Spontaneous fermentations using grape must from Treixadura, Albariño, Lado, Godello, and Loureira varieties were carried out at experimental winery of Evega. Yeasts were isolated from must and at different stages of fermentation. Those colonies belonging to Saccharomyces cerevisiae were characterized at strain level by mDNA-RFLPs.

Yeast species S. cerevisiae, S. uvarum, S. kudriavzevii and their hybrids present clear metabolic differences, even when we compared S. cerevisiae wine versus wild strain. These species and hybrids produced significantly higher amounts of glycerol, organic acids, 2,3-butanediol, and 2-phenyl ethanol and a reduction of the ethanol yield, properties very interesting in the sector to deal with climate change effects. To understand the existing differences, we have used several omics techniques to analyze the dynamics of the (intra- and extracellular) metabolomes and/or transcriptomes of representative strains of S. cerevisiae, S. uvarum, S. kudriavzevii, and hybrids.

Viticulture’s adaptation to the harmful effects of climate change is globally the biggest challenge of the near future. Short, extremely intensive rainfalls and longer periods of drought are getting more frequent in the Tokaj Wine Region, where the majority of the vineyards are cultivated on steep slopes. Hence, erosion has high risk, especially when combined with the loess-based soils on about ten percent of the region. The environmentally beneficial cover crop and mulch usage can effectively reduce the risk of erosion, according to research done by the Tokaj Wine Region Research Institute of Viticulture and Oenology.

The use of grapevine genetic diversity is a way to mitigate the negative impacts of climate change on viticulture systems. Leaf epidermal flavonoids (including flavonols and anthocyanins) are involved in plant defense mechanisms against environmental stresses, like high temperatures or excessive solar radiation [1,2]. Among other factors, they modulate light absorption, which reduces photoinhibition processes in photosynthetic tissues [1]. Therefore, the identification of grapevine cultivars with an increased content on leaf epidermal flavonoids arises as a potential avenue to improve grapevine tolerance to some detrimental environmental stresses.