A complex protein derivative acts as biogenic elicitor of grapevine resistance against powdery mildew under field conditions.

Andrea Nesler,Oscar Giovannini,Ilaria Pertot,Gerardo Puopolo,Yigal Elad,Michele Perazzolli

doi:10.3389/fpls.2015.00715

Andrea Nesler, Oscar Giovannini + Show 4 more

Open Access

https://doi.org/10.3389/fpls.2015.00715

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Abstract

Powdery mildew caused by Erysiphe necator is one of the most important grapevine diseases in several viticulture areas, and high fungicide input is required to control it. However, numerous synthetic chemical pesticides are under scrutiny due to concerns about their impact on human health and the environment. Biopesticides, such as biogenic elicitors, are a promising alternative to chemical fungicides. Although several studies have reported on effective elicitors against grapevine diseases, their efficacy under field conditions has not been investigated extensively or has occurred at rather limited levels. Our goal was to examine the efficacy of a protein-based composition, namely nutrient broth (NB), against powdery mildew under field conditions and to characterize its mechanism of action. Weekly treatments with NB was highly effective in controlling powdery mildew on grapevine across seasons with different disease pressures. The level of disease control achieved with NB was comparable to standard fungicide treatments both on leaves and bunches across three different years. NB has no direct toxic effect on the germination of E. necator conidia, and it activates plant resistance with both systemic and translaminar effect in experiments with artificial inoculation under controlled conditions. NB induced the expression of defense-related genes in grapevine, demonstrating stimulation of plant defense mechanisms, prior to and in the early stages of pathogen infection. NB is a natural derivative from meat and yeast, substances that tend not to raise concerns about toxicological and ecotoxicological properties. NB represents a valid control tool for integrated plant protection programs against powdery mildew, to reduce the use of synthetic pesticides on grapevine.

Highlights

Synthetic chemical pesticides have contributed significantly to the sizable increase in global production of agricultural goods in recent decades (Hillocks, 2012)
Evaluation of the Efficacy of Nutrient Broth against Grapevine Powdery Mildew under Field Conditions Laboratory protein extracts were tested against powdery mildew on zucchini plants
The efficacy was statistically comparable to 2.0 g/l nutrient broth (NB) and 5.0 g/l beef extract, 5.0 g/l NB provided the greatest reduction of powdery mildew symptoms (Figure S2) and this formulation was used in the field trials

Summary

Introduction

Synthetic chemical pesticides have contributed significantly to the sizable increase in global production of agricultural goods in recent decades (Hillocks, 2012). The overuse of pesticides has raised concerns about their impact on human health and the environment (Fantke et al, 2012). For these reasons, the European Union (EU), along with many countries around the world, has implemented stringent regulations on the registration of plant protection products, and directed policies toward achieving significant reductions in pesticide use (Hillocks, 2012; Skevas et al, 2013). Some natural chemicals used against powdery mildews, such as sulfur, are not without negative effects (e.g., an undesirable reduction of predatory mites, a risk of skin and eye irritation for humans, the potential to cause unpleasant aromas in wine)

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