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

Nesler A, Perazzolli M, Puopolo G, Giovannini O, Elad Y, Pertot I - Front Plant Sci (2015)

Bottom Line: 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.Weekly treatments with NB was highly effective in controlling powdery mildew on grapevine across seasons with different disease pressures.NB represents a valid control tool for integrated plant protection programs against powdery mildew, to reduce the use of synthetic pesticides on grapevine.

View Article: PubMed Central - PubMed

Affiliation: Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach San Michele all'Adige, Italy.

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.

No MeSH data available.


Related in: MedlinePlus

Effect of nutrient broth against powdery mildew on grapevine plants under greenhouse conditions. Powdery mildew severity was assessed on grapevine leaves treated with water (Control), nutrient broth (NB) or sulfur (Sulfur), as standard fungicide for 3 days before pathogen inoculation. Disease severity was assessed as percentage of adaxial leaf area covered by white sporulation 13 days post-inoculation, and two independent experiments were carried out under greenhouse conditions. The mean severity and standard error values of nine replicates (potted plants) are presented for each treatment and experiment. Uppercase and lowercase letters indicate significant differences among treatments according to Tukey's HSD test (α = 0.05) in Experiments 1 (Exp1) and 2 (Exp2), respectively.
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Figure 4: Effect of nutrient broth against powdery mildew on grapevine plants under greenhouse conditions. Powdery mildew severity was assessed on grapevine leaves treated with water (Control), nutrient broth (NB) or sulfur (Sulfur), as standard fungicide for 3 days before pathogen inoculation. Disease severity was assessed as percentage of adaxial leaf area covered by white sporulation 13 days post-inoculation, and two independent experiments were carried out under greenhouse conditions. The mean severity and standard error values of nine replicates (potted plants) are presented for each treatment and experiment. Uppercase and lowercase letters indicate significant differences among treatments according to Tukey's HSD test (α = 0.05) in Experiments 1 (Exp1) and 2 (Exp2), respectively.

Mentions: Foliar applications of NB significantly reduced powdery mildew symptoms of the susceptible cultivar Pinot noir under greenhouse conditions (Figure 4). The two experiments were analyzed separately because a slight effect of the “experiment” factor was present (F-test, p = 0.03). NB treatment significantly reduced the level of disease severity, with an efficacy greater than 60% in both experiments, and the efficacy of sulfur was greater than 84%. In order to investigate the molecular mechanisms of the grapevine induced resistance, the relative expression levels of five defense-related genes (Table S1) were analyzed by RT-qPCR. The expression of the PR protein 1 (PR-1) gene was induced at 6 (more than 9-fold) and 13 (more than 85-fold) dpi of powdery mildew inoculation in control plants (Figure 5A). PR-1 was induced more than 10-fold in NB-treated plants at 0 and 1 dpi in both the experiments. The expression level of PR-1 further increased at 6 dpi (70-fold) and 13 dpi (44-fold) in NB-treated plants in experiment 1. In experiment 2, the expression level of PR-1 at 6 dpi (12-fold) and 1 dpi were comparable, and reached 32-fold at 13 dpi. In both the experiments, the expression level of PR-1 was greater in NB-treated than in control plants at 0 and 1 dpi, but not at 6 and 13 dpi. The expression level of PR-1 was not affected by powdery mildew inoculation in sulfur-treated plants at any of the time points tested, and it was slightly induced at 13 dpi in Experiment 1.


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

Nesler A, Perazzolli M, Puopolo G, Giovannini O, Elad Y, Pertot I - Front Plant Sci (2015)

Effect of nutrient broth against powdery mildew on grapevine plants under greenhouse conditions. Powdery mildew severity was assessed on grapevine leaves treated with water (Control), nutrient broth (NB) or sulfur (Sulfur), as standard fungicide for 3 days before pathogen inoculation. Disease severity was assessed as percentage of adaxial leaf area covered by white sporulation 13 days post-inoculation, and two independent experiments were carried out under greenhouse conditions. The mean severity and standard error values of nine replicates (potted plants) are presented for each treatment and experiment. Uppercase and lowercase letters indicate significant differences among treatments according to Tukey's HSD test (α = 0.05) in Experiments 1 (Exp1) and 2 (Exp2), respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585195&req=5

Figure 4: Effect of nutrient broth against powdery mildew on grapevine plants under greenhouse conditions. Powdery mildew severity was assessed on grapevine leaves treated with water (Control), nutrient broth (NB) or sulfur (Sulfur), as standard fungicide for 3 days before pathogen inoculation. Disease severity was assessed as percentage of adaxial leaf area covered by white sporulation 13 days post-inoculation, and two independent experiments were carried out under greenhouse conditions. The mean severity and standard error values of nine replicates (potted plants) are presented for each treatment and experiment. Uppercase and lowercase letters indicate significant differences among treatments according to Tukey's HSD test (α = 0.05) in Experiments 1 (Exp1) and 2 (Exp2), respectively.
Mentions: Foliar applications of NB significantly reduced powdery mildew symptoms of the susceptible cultivar Pinot noir under greenhouse conditions (Figure 4). The two experiments were analyzed separately because a slight effect of the “experiment” factor was present (F-test, p = 0.03). NB treatment significantly reduced the level of disease severity, with an efficacy greater than 60% in both experiments, and the efficacy of sulfur was greater than 84%. In order to investigate the molecular mechanisms of the grapevine induced resistance, the relative expression levels of five defense-related genes (Table S1) were analyzed by RT-qPCR. The expression of the PR protein 1 (PR-1) gene was induced at 6 (more than 9-fold) and 13 (more than 85-fold) dpi of powdery mildew inoculation in control plants (Figure 5A). PR-1 was induced more than 10-fold in NB-treated plants at 0 and 1 dpi in both the experiments. The expression level of PR-1 further increased at 6 dpi (70-fold) and 13 dpi (44-fold) in NB-treated plants in experiment 1. In experiment 2, the expression level of PR-1 at 6 dpi (12-fold) and 1 dpi were comparable, and reached 32-fold at 13 dpi. In both the experiments, the expression level of PR-1 was greater in NB-treated than in control plants at 0 and 1 dpi, but not at 6 and 13 dpi. The expression level of PR-1 was not affected by powdery mildew inoculation in sulfur-treated plants at any of the time points tested, and it was slightly induced at 13 dpi in Experiment 1.

Bottom Line: 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.Weekly treatments with NB was highly effective in controlling powdery mildew on grapevine across seasons with different disease pressures.NB represents a valid control tool for integrated plant protection programs against powdery mildew, to reduce the use of synthetic pesticides on grapevine.

View Article: PubMed Central - PubMed

Affiliation: Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach San Michele all'Adige, Italy.

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.

No MeSH data available.


Related in: MedlinePlus