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నైరూప్య

Phytoalexins Stilbenoids in leaves of V. vinifera L. cv. Cabernet Sauvignon as affected by downy mildew (Plasmopara viticola Berl.) infection

Magdana A. Surguladze, Marine G.  Bezhuashvili, Luigi Bavaresco, Liudmila P. Tskhvedadze, Giorgi S. Shoshiashvili, Lali D. Elanidze and Paata N. Vashakidze

Statement of the Problem: Incorrect use of pesticides has changed the bio-environment, while their presence in wine is harmful for the human health. Therefore, producing and using ecologically friendly preparations is an internationally topical issue in fighting vine bacterial and fungal diseases. In producing ecologically friendly preparations, worthwhile and important are biologically active substances like the stilbenoids, behaving as phytoalexins. The physiology of vine stilbenoids in relation to the occurrence of some diseases due to bacteria (Agrobacterium tumefaciens) and fungi  (Plasmopara viticola, Botrytis cinerea, Uncinula necator) have been studied in Georgian red and white grape variety. The purpose of this study is to study the change of leaf stilbenoid concentration of the red grape variety Cabernet Sauvignon under downy mildew infection.

Methodology & Theoretical Orientation: Samples of healthy and infected leaves were taken from a 35- year-old vineyard, located in the Kakheti region (East Georgia), during July 2019.  The   total fraction of stilbenoids was isolated by extraction with ethyl acetate, a “Sephadex G25” column was utilized, and the analysis was done by   HPLC/MS method.

Findings: Downy mildew infection affected the stilbenoid leaf concentration as compared to healthy leaves.

Conclusion & Significance: Trans-Resveratrol, trans-ε-viniferin and cis-piceid were the major detected stilbenoids.  Trans-Resveratrol concentration was higher   in infected leaves while trans- ε-viniferin   and cis- piceid were a little lower in infected leaves, as compared to the healthy ones.