Influence of organic plant treatment on the terroir of microorganisms

Xylotrechus arvicola (Coleoptera: Cerambycidae) is a pest in vineyards (Vitis vinifera) in the main Spain wine-producing regions with Protected Denomination of Origin (PDO). The action of the larvae, associated to the spreading of wood fungi, causes damage especially in important varieties of V. vinifera. X. arvicola females lay eggs concentrated in cracks or under the rhytidome in the wood vines, which allows the emerging larvae to get into the wood and make galleries inside the plant being then necessary to prune intensively or to pull up the bored plants (1). The objective of the study was to evaluate captures of X. arvicola insects in five varieties of V. vinifera in PDO León.

According to the last IPCC report, the scale of recent climate changes are unprecedented over many centuries. Each of the last four decades has been successively warmer than any decade since 1850. Projections for the future foresee that temperature could reach +3.3°C to +5.7°C under the most pessimistic scenario. It is also projected that every region will face more concurrent and multiple changes in climatic impact-drivers. The frequency of extreme climate events is also likely to increase, as well as the occurrence of indirect constraints. These evolving climatic conditions are alrealdy affecting and will continue to affect the suitability of traditional wine grape production areas, but also create opportunities in new locations.

Grape canes are a non-recycled byproduct of wine industry (1-5 tons per hectare per year) containing valuable phytochemicals of medicine and agronomical interest. Resveratrol and wine polyphenols are known to exert a plethora of health-promoting effects including antioxidant capacity, cardioprotection, anticancer activity, anti-inflammatory effects, and estrogenic/antiestrogenic properties (Guerrero et al. 2009). Additionally, resveratrol is a major phytoalexin produced by plants in response to various stresses and promotes disease resistance (Chang et al. 2011). Our project aims to develop polyphenol-rich grape cane extracts to fight phytopathogenic or clinically relevant fungi. We initiate the project with the development of analytical methods to analyze resveratrol mono- and oligomers (dimers, trimers and tetramers) from grape canes and we evaluate their potential activity against clinically relevant opportunistic fungal pathogens (Houillé et al. 2014).

Condensed tannins (CTs), polymers of flavan-3-ols, are a class of polyphenolic compounds that play a significant role in the organoleptic qualities of red wines, particularly influencing color, astringency and bitterness. These properties are highly dependent on size and structure of these compounds.

Contribution Sparkling wines elaborated following the traditional method undergo a second fermentation in closed bottles of base wines, followed by aging of wines with lees for at least 9 months. Most of the sparkling wines elaborated are white and rosé ones, although the production of red ones is highly increasing. One of the initial problems in red sparkling wine processing is to obtain suitable base wines that should have moderate alcohol content and astringency and adequate color intensity; which is difficult to obtain when grapes must be harvested at low phenolic and industrial maturity stage. The low phenolic maturity degree in the red grapes makes essential to choose an adequate winemaking methodology to obtain the base wines because the extracted polyphenols will vary according the winemaking technique: carbonic maceration or destemmed-crushed grapes.