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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 grape bunches under field conditions. Powdery mildew severity and incidence was assessed on bunches of grapevines treated with water (Control), nutrient broth (NB) or sulfur (Sulfur), as standard fungicide, under field conditions in three different seasons (2010, 2011, and 2013). Treatments were applied weekly from the beginning of May to the middle of August. Disease severity and incidence were assessed weekly as percentage of bunch area covered by white sporulation and percentage of bunches showing symptoms by scoring 20 bunches per replicate, respectively. The mean severity and incidence scores and the standard errors of three replicates (eight plants each) are presented for each treatment. For each year, uppercase and lowercase letters indicate significant differences among treatments according to Tukey's HSD test (α = 0.05) of disease severity and incidence, respectively.
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Figure 2: Effect of nutrient broth against powdery mildew on grape bunches under field conditions. Powdery mildew severity and incidence was assessed on bunches of grapevines treated with water (Control), nutrient broth (NB) or sulfur (Sulfur), as standard fungicide, under field conditions in three different seasons (2010, 2011, and 2013). Treatments were applied weekly from the beginning of May to the middle of August. Disease severity and incidence were assessed weekly as percentage of bunch area covered by white sporulation and percentage of bunches showing symptoms by scoring 20 bunches per replicate, respectively. The mean severity and incidence scores and the standard errors of three replicates (eight plants each) are presented for each treatment. For each year, uppercase and lowercase letters indicate significant differences among treatments according to Tukey's HSD test (α = 0.05) of disease severity and incidence, respectively.

Mentions: Laboratory protein extracts were tested against powdery mildew on zucchini plants. Although the efficacy was statistically comparable to 2.0 g/l 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. In 2010 and 2011, primary infections occurred very early in the season and the first signs of the disease were observed on June 6 and May 19, respectively. The disease intensified very quickly in these two seasons, resulting in high levels of severity and incidence on leaves of control plants (Figure 1). In 2013, due to unsuitable conditions for the disease (high mean daily temperatures and low precipitation starting in June), powdery mildew developed slowly and very late in the season and symptoms were observed mainly on bunches rather than leaves starting on July 7 on control plants. The onset of the disease occurred almost at the same time on leaves of control, NB- and sulfur-treated plants in the 3 years tested. However, disease progress during the season was slower in NB- and sulfur-treated plants compared to control plants, resulting in significantly lower levels of powdery mildew severity and incidence during the season. AUDPC calculated for severity and incidence on leaves of NB-treated plants was comparable to sulfur-treated plants and significantly lower than that of control plants across the 3 years (Table 1). Likewise, powdery mildew severity on grape bunches was significantly lower on NB-treated plants compared to control plants at the end of each of the 3 years tested, and was comparable to that of sulfur-treated plants (Figure 2). Disease incidence was significantly reduced by NB treatments on bunches in 2010 and 2011, but not in 2013. Except for the slight phytotoxic effects of 5 g/l NB at the end of the 2010 season, no negative effect of 3 g/l NB on leaf morphology, shoot growth and fruit yield were visible at the end of the 2011 and 2013 seasons (Figure S1).


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 grape bunches under field conditions. Powdery mildew severity and incidence was assessed on bunches of grapevines treated with water (Control), nutrient broth (NB) or sulfur (Sulfur), as standard fungicide, under field conditions in three different seasons (2010, 2011, and 2013). Treatments were applied weekly from the beginning of May to the middle of August. Disease severity and incidence were assessed weekly as percentage of bunch area covered by white sporulation and percentage of bunches showing symptoms by scoring 20 bunches per replicate, respectively. The mean severity and incidence scores and the standard errors of three replicates (eight plants each) are presented for each treatment. For each year, uppercase and lowercase letters indicate significant differences among treatments according to Tukey's HSD test (α = 0.05) of disease severity and incidence, respectively.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 2: Effect of nutrient broth against powdery mildew on grape bunches under field conditions. Powdery mildew severity and incidence was assessed on bunches of grapevines treated with water (Control), nutrient broth (NB) or sulfur (Sulfur), as standard fungicide, under field conditions in three different seasons (2010, 2011, and 2013). Treatments were applied weekly from the beginning of May to the middle of August. Disease severity and incidence were assessed weekly as percentage of bunch area covered by white sporulation and percentage of bunches showing symptoms by scoring 20 bunches per replicate, respectively. The mean severity and incidence scores and the standard errors of three replicates (eight plants each) are presented for each treatment. For each year, uppercase and lowercase letters indicate significant differences among treatments according to Tukey's HSD test (α = 0.05) of disease severity and incidence, respectively.
Mentions: Laboratory protein extracts were tested against powdery mildew on zucchini plants. Although the efficacy was statistically comparable to 2.0 g/l 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. In 2010 and 2011, primary infections occurred very early in the season and the first signs of the disease were observed on June 6 and May 19, respectively. The disease intensified very quickly in these two seasons, resulting in high levels of severity and incidence on leaves of control plants (Figure 1). In 2013, due to unsuitable conditions for the disease (high mean daily temperatures and low precipitation starting in June), powdery mildew developed slowly and very late in the season and symptoms were observed mainly on bunches rather than leaves starting on July 7 on control plants. The onset of the disease occurred almost at the same time on leaves of control, NB- and sulfur-treated plants in the 3 years tested. However, disease progress during the season was slower in NB- and sulfur-treated plants compared to control plants, resulting in significantly lower levels of powdery mildew severity and incidence during the season. AUDPC calculated for severity and incidence on leaves of NB-treated plants was comparable to sulfur-treated plants and significantly lower than that of control plants across the 3 years (Table 1). Likewise, powdery mildew severity on grape bunches was significantly lower on NB-treated plants compared to control plants at the end of each of the 3 years tested, and was comparable to that of sulfur-treated plants (Figure 2). Disease incidence was significantly reduced by NB treatments on bunches in 2010 and 2011, but not in 2013. Except for the slight phytotoxic effects of 5 g/l NB at the end of the 2010 season, no negative effect of 3 g/l NB on leaf morphology, shoot growth and fruit yield were visible at the end of the 2011 and 2013 seasons (Figure S1).

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