The effect of Saccharomyces cerevisiae on antioxidant system of grape leaves infected by downy mildew

Federal State Budget Scientific Institution «North Caucasian Federal Scientific Center of Horticulture, Viticulture, Wine-making», 40 years of Victory Street, 39, 350901 Krasnodar, Russia

^* Corresponding author: A. Mishko; mishko-alisa@mail.ru

Abstract

In this article, results of the comparative analysis and assessment of resistance of two grape cultivars Vostorg and Muscat blanc against downy mildew disease (Plasmopara viticola) with or without the symbiote Saccharomyces cerevisiae (vine yeast) were shown. The highly resistant cultivar Vostorg with yeast pre-treatment demonstrated a high defensive capability to the pathogen due to the fast immune response. On the first day after inoculation with downy downy mildew the rapid increase in the hydrogen peroxide, which is involved the first step of the grape’s defense system induction, was observed. At the same time, the upregulation of the relative expression of the PR2 protein (β-1,3-gluconase), a key gene involved in the plant’s resistance to pathogens. The oxidative burst was not detected in the susceptible cultivar Muscat blanc for the couple of hours after inoculation with downy mildew pathogen. The significant increase of the total phenols content and expression of stilbene synthase, which is an enzyme involved in the synthesis of phytoalexins, was observed in leaves of Muscat blanc. It was shown that pre-treatment of grape leaves with natural symbiote S. cerevisiae enhanced the immune response of the resistant cultivar Vostorg and inducted phytoalexins synthesis in the susceptible cultivar Muscat blanc.