In vitro Antifungal Activity of a New Bioproduct Obtained from Grape Seed Proanthocyanidins on Botrytis cinerea Mycelium and Spores

Ancuța Nechita,Roxana M Filimon,Razvan V Filimon,Doina Damian,Rodica Pașa,Daniela Gherghel,Valeriu V Cotea,Lucia-Cintia Colibaba

doi:10.15835/nbha47111367

Abstract

Botrytis cinerea is a necrotrophic fungus that affects over 200 plant species. In vineyards, this pathogen is responsible for one of the most important diseases, commonly known as botrytis bunch rot or grey mould. Keeping infection under control with synthetic fungicides leads to an increased biological resistance of pathogen populations. An alternative way to synthetic products is to obtain natural fungicides by using bioactive compounds of plants. This study focuses on the antifungal properties of a new bioproduct obtained from polymeric proanthocyanidins extracted from grape seeds of ‘Fetească neagră’ variety. The bioproduct in solid state presented a total content of polyphenols of 0.625 mg GAE mg-1, a polyphenolic index of 17.40 and an antioxidant activity of 91.27% scavenged DPPH. The bioproduct with polyphenolic structure showed a moderate effect on the radial growth of fungal mycelium, at EC50 values between 11.23 and 12.15 mg mL-1. Effective antifungal activity was showed in the inhibition of spore germination, where the EC50 values varied from 1.14 to 1.47 mg mL-1. These in vitro results sustain the possibility of including the bioproduct in the category of natural fungicides for biological control against Botrytis cinerea fungus.

Highlights

In vineyards, among other pathogenic species, Botrytis cinerea Pers. is the most aggressive specie, causing significant economic damages (Gatto, 2011)
The bioproduct, obtained through controlled oxidation of the waterinsoluble polymeric PA preparation appears as yellowbrown crusts, soluble in distilled water, with a total amount of polyphenolic compounds of 0.625 mg gallic acid equivalent (GAE) mg-1, with an antioxidant activity of 91.37% scavenged DPPH per 100 μg
In Petri dishes with potato dextrose agar (PDA) medium, where the tested concentrations of the bioproduct were introduced, the spore germination was visible after 48 hours. These findings suggest that the tested bioproduct is active on the inhibition of spore germination, mainly due to the strong action of phenolic compounds on the growth and elongation of spore germ tube, as was previously reported by Nassr and Barakat (2013)

Summary

Introduction

Among other pathogenic species, Botrytis cinerea Pers. is the most aggressive specie, causing significant economic damages (Gatto, 2011). Control of infection with Botrytis cinerea is currently performed with synthetic fungicides, but their danger has been proven, both for consumers and the environment due to the long time required for degradation (Lingk, 1991). Their frequent use in treatments promotes the emergence of resistant strains of Botrytis cinerea (Elad and Evensen, 1995). In plant defense system against pathogenic fungi, phenolic compounds are directly involved.

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