Effect of post-harvest ozone treatment on secondary metabolites biosynthesis and accumulation in grapes and wine

Pierce’s disease (PD) is considered a potential threat to european viticulture (EPPO a2 list of pathogens since 1981). In the usa, infections caused by the vector-borne bacterium xylella fastidiosa have caused recurrent damage to vineyards in California and the southeastern states. However, vineyards in Europe have remained free of PD until recently, when it was first detected on the island of Mallorca in 2017. The reasons for the absence of PD in continental Europe have not been convincingly explained.

Ozone is a potent oxidizing compound that quickly decomposes into oxygen without residues. Previous works reported that ozone is not only a disinfectant that directly harms the pathogens of the vine but also activates systemic defense systems in the plant by activating oxidative stress. We assume these systemic defense mechanisms are essential to the vines’ resistance to downy and powdery mildew (Plasmopara viticola & Erysiphe necator, respectively). The goals of the research are to examine the effect of spraying with ozone water on the plant’s resistance against the mentioned pathogens as well as to characterize the metabolic profile of the plants treated with ozone as well as physiological characteristics in the vines such as the level of Photosynthesis and crop yield. Vines in the vineyard sprayed with ozone water at concentrations of 2 and 4 PPM weekly and biweekly, untreated control & conventional spray. Leaves were taken from vines 2,4,7,9 and 11 days after exposure to ozone and inoculated with the pathogens.

Soil is important in the carbon cycle and the dynamics of greenhouse gases (CO2, CH4 and N2O). Key soil characteristics, such as organic matter content, texture, structure, pH and microbial activity, play a determining role in GHG emissions[1]. The objective of the study is to delimit different types of soil, with different soil management and to be able to verify the differences in CO2, CH4 and N2O emissions. The study was carried out in a vineyard of Bodegas Campo Viejo in Logroño (La Rioja), whose plant material is Vitis vinifera L. cv. Tempranillo.

In previous experiments carried out in Bologna on Sangiovese grapevines raised with the Australian “Minimal Pruning” system, it has been shown that this system left an excessive burden of buds on the vine.

It is widely known the impact that oxidation has on wine sensory degradation and eventually, in the shortening of its longevity.