Changes in Grape Berry Exudates during Fruit Development and Their Effect on Mycelial Growth of Botrytis cinerea

Abstract

<jats:p>Grape berries <jats:italic>(Vitis vinifera</jats:italic> L., `Thompson Seedless') exuded a variety of compounds through the cuticle and epicuticular wax layer onto the berry surface. The composition of the exudate changed through the course of the growing season. Phenolic compounds and malic acid were in relatively high concentrations in grape berry exudates after bloom, but were low in exudates from mature fruit. The rate of decrease of phenols and malic acid was more rapid during the early stage of berry growth than during the ripening period. Sugar and potassium concentrations in the berry exudates were low at bloom, but increased rapidly in the later stages of ripening. Water extracts of berry exudates contained sugars, malic acid, potassium, and sodium. The water extracts promoted mycelial growth of Botrytis <jats:italic>cinerea</jats:italic> Pers. Ethanol and ether extracts contained phenols and lipids. These fractions from fruit sampled in the first 3 weeks after bloom strongly inhibited mycelial growth. The inhibitory effect of these fractions decreased later in the season.</jats:p>

Grape berry skin features related to ontogenic resistance to Botrytis cinerea

“…These authors considered phenolic compounds and polymeric proanthocyanidins (PPRAs) or tannins from the berry skin as toxic to B. cinerea, inhibiting both the polygalacturonase and the laccase-like stilbene oxidase activities. Furthermore, although Mlikota-Gabler et al (2003) did not find any association, other studies showed a significant correlation between a low grapevine susceptibility and a high phenolic content (Sarig et al 1998), in particular, phenolic compounds linked to the parietal structures in the berry skin (Dubos and Roudet 2003) and those detected in exudates from the grape berry (Padgett and Morrison 1990). Our results concerning the chemical composition of the berry skin corroborate this.…”

“…(2003) Aw is clearly related to most physical degradation reactions. The structural alteration of the grape berry skin, with less cell layers, contribute to an exosmosis increase during ripening, thereby providing substantial amounts of nutrients to the epiphytic microorganisms, including B. cinerea (Donèche 1986;Padgett and Morrison 1990). Concurrently, the presence of these soluble compounds on the skin must increase the solute concentration in free water at the berry surface, thus leading to a decrease in Aw (as shown in this study).…”

Characterization of Epiphytic Bacterial Communities from Grapes, Leaves, Bark and Soil of Grapevine Plants Grown, and Their Relations

“…Grape skins, especially in the early stages of ripening, also provide a limited amount of nutrients to sustain bacterial growth [53], [54], [55]. Furthermore, the surface of leaves and grapes contains compounds such as stilbenes (resveratrol and derivatives), which are involved in plant and fruit defences against microbial activity [56], [57].…”

Classification of winegrape cultivars in Chile and France according to their susceptibility toBotrytis cinerearelated to fruit maturity

“…Some of these studies also demonstrated that the presence of sugar in berry exudates stimulates the germination and mycelium growth of B. cinerea (Kosuge and Hewitt 1964, Blakeman 1980, Coley-Smith 1980, Doneche 1986, Padgett and Morrison 1990, Vercesi et al 1997, Deytieux-Belleau et al 2009). Several studies, often based on one selected model cultivar, have demonstrated that increasing sugar concentration with the phenological stage in maturing grape berries promotes infection and colonisation by B. cinerea.…”