Exploring the inner secrets of grapevine: a journey through plant-microbe interactions

Introduction: Malolactic fermentation (MLF) is a common process in winemaking to reduce wine acidity, maintain microbial stability and modify wine aroma. However, successful MLF is often hampered by their sluggish or stuck activity of malolactic bacteria (MLB) which may be caused by nutrient deficiency, especially when MLB are inoculated after alcoholic fermentation (Alexandre et al., 2004; Lerm et al., 2010). Identification and characterization of essential nutrients and growth factors for MLB allows for production of highly efficient nutrient supplements for MLF.

Nitrogen composition of grape berries plays a key role in determining wine quality, affecting the development of alcoholic fermentation and the formation of volatile compounds. Grape nitrogen composition is influenced by several factors such as viticultural practices, soil management, timing or rate of fertilization and use of rootstock, among others.In this study a proximal, non-destructive tool based on NIR spectroscopy is presented to track the accumulation of a wide range of amino acids in intact grape berries during the ripening process.

In Washington State, the majority of winegrape (Vitis vinifera) vineyards are planted to their own roots. This practice is possible due to the lack of established phylloxera populations, and is preferred due to the ease of retraining after damaging winter cold events. However, own-rooted V. vinifera is generally susceptible to most plant parasitic nematodes that attack grape. In Washington State, management of nematodes is dominated by preplant soil fumigation. One practice that may mitigate economic loss due to nematodes is the adoption of nematode-“resistant” rootstocks.

Grape typicity valorization can significantly enhance viticultural sector competitiveness to the extent that contributes to the development of a wine so distinctive and unique. This work leads to the characterization of the grapes through indicators expressing environmental effects.

Powdery mildew (Erysiphe necator) (PM) is the most important and impacting fungal disease of grapevine (Vitis vinifera L). This disease remains difficult to model and forecast accurately because (i) the first signs of the disease in the vineyard are hardly noticeable in the first 30- 40 days after the onset of the epidemic (three to four pathogen generations), and (ii) its spatial distribution within or between neighboring plots is heterogeneous.