Abstract
Downy mildew, caused by Plasmopara viticola , poses a major threat to grapevine production, necessitating effective and sustainable disease management strategies. Ascophyllum nodosum extract (ANE) and Pseudomonas fluorescens CHA0 possess biostimulant and biocontrol properties, respectively, with reported potential to induce plant defense against various pathogens. However, their combined application and potential synergistic effects in grapevine disease management remain largely unexplored. In this study, their efficacy in controlling downy mildew in grapevines was investigated. Our results demonstrate that both ANE and CHA0, individually and in combination, significantly reduced downy mildew severity. In vitro assays revealed that grape leaves treated with ANE, CHA0, or their combination suppressed disease establishment and progression, with the combined treatment showing the greatest reduction in spore count (~66%), zoospore numbers (~89–93%), and empty sporangia (~53–69%). In vivo greenhouse experiments confirmed these findings, showing that combined foliar applications of ANE and CHA0 reduced downy mildew incidence to approximately 22%, compared to 40–50% with individual treatments and 70% in untreated controls, implying a synergistic interaction between these treatments. In addition to disease suppression, combined ANE and CHA0 applications triggered robust biochemical and molecular defense responses in grapevines. Key defense enzymes, including phenylalanine ammonia lyase, peroxidase, and polyphenol oxidase, showed significantly enhanced activities, accompanied by elevated levels of phenolics and hydrogen peroxide. At the molecular level, the combination significantly upregulated stress-responsive genes such as CHI , GLP2 and GLP7 , along with jasmonic acid-responsive genes including LOX9 , OSM1 , and PR4 , suggesting a priming effect that reinforces the plant’s innate immune responses. Overall, these findings highlight the potential of combined ANE and CHA0 treatments in enhancing grapevine resistance to downy mildew through the activation of defense mechanisms and modulation of key biochemical markers. The synergistic interplay between the biostimulant and biocontrol agent offers a promising eco-friendly alternative to conventional chemical-based disease management in viticulture.
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Claims 11
Claim · model-written summary
ANE alone significantly reduced downy mildew severity.
- Treatment
- ANEe0
- Interactor
- Plasmopara viticola
Plasmopara viticolae2pathogen - Outcome
- downy mildew severitye0
- Direction
- reducede0
VitisNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both ANE and CHA0, individually and in combination, significantly reduced downy mildew severity.”
e1“downy mildew in grapevines”
e2“Downy mildew, caused by Plasmopara viticola”
Claim · model-written summary
CHA0 alone significantly reduced downy mildew severity.
- Treatment
- CHA0e0
- Interactor
- Plasmopara viticolaPlasmopara viticolae2pathogen
- Second interactor
- Pseudomonas fluorescens CHA0
.JPG?width=60)
Pseudomonas fluorescenst0biocontrol_agent - Outcome
- downy mildew severitye0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.JPG?width=500)
Verbatim
e0“both ANE and CHA0, individually and in combination, significantly reduced downy mildew severity.”
e1“downy mildew in grapevines”
e2“Downy mildew, caused by Plasmopara viticola”
t0“Pseudomonas fluorescens CHA0”
Claim · model-written summary
Combined ANE and CHA0 significantly reduced downy mildew severity.
- Treatment
- ANE and CHA0e0
- Interactor
- Plasmopara viticolaPlasmopara viticolae2pathogen
- Second interactor
- Pseudomonas fluorescens CHA0Pseudomonas fluorescenst0biocontrol_agent
- Outcome
- downy mildew severitye0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both ANE and CHA0, individually and in combination, significantly reduced downy mildew severity.”
e1“downy mildew in grapevines”
e2“Downy mildew, caused by Plasmopara viticola”
t0“Pseudomonas fluorescens CHA0”
Claim · model-written summary
The combined treatment reduced spore count by about 66%.
- Taxon
- grapee1
- Treatment
- combined treatmente0
- Interactor
- Plasmopara viticolaPlasmopara viticolae2pathogen
- Outcome
- spore counte0
- Direction
- reductione0
- Value
- ~66%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the combined treatment showing the greatest reduction in spore count (~66%), zoospore numbers (~89–93%), and empty sporangia (~53–69%).”
e1“grape leaves”
e2“Downy mildew, caused by Plasmopara viticola”
Claim · model-written summary
The combined treatment reduced zoospore numbers by about 89–93%.
- Taxon
- grapee1
- Treatment
- combined treatmente0
- Interactor
- Plasmopara viticolaPlasmopara viticolae2pathogen
- Outcome
- zoospore numberse0
- Direction
- reductione0
- Value
- ~89–93%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the combined treatment showing the greatest reduction in spore count (~66%), zoospore numbers (~89–93%), and empty sporangia (~53–69%).”
e1“grape leaves”
e2“Downy mildew, caused by Plasmopara viticola”
Claim · model-written summary
The combined treatment reduced empty sporangia by about 53–69%.
- Taxon
- grapee1
- Treatment
- combined treatmente0
- Interactor
- Plasmopara viticolaPlasmopara viticolae2pathogen
- Outcome
- empty sporangiae0
- Direction
- reductione0
- Value
- ~53–69%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the combined treatment showing the greatest reduction in spore count (~66%), zoospore numbers (~89–93%), and empty sporangia (~53–69%).”
e1“grape leaves”
e2“Downy mildew, caused by Plasmopara viticola”
Claim · model-written summary
Combined foliar applications reduced incidence to approximately 22%, versus 40–50% with individual treatments and 70% untreated.
- Treatment
- combined foliar applications of ANE and CHA0e0
- Interactor
- Plasmopara viticolaPlasmopara viticolae2pathogen
- Outcome
- downy mildew incidencee0
- Direction
- reducede0
- Value
- 22%e0
- Qualifier
- 40–50% with individual treatments and 70% in untreated controlse0
- Comparator
- untreated controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“combined foliar applications of ANE and CHA0 reduced downy mildew incidence to approximately 22%, compared to 40–50% with individual treatments and 70% in untreated controls”
e1“downy mildew in grapevines”
e2“Downy mildew, caused by Plasmopara viticola”
Claim · model-written summary
Combined applications enhanced phenylalanine ammonia lyase, peroxidase, and polyphenol oxidase activities.
- Treatment
- combined ANE and CHA0 applicationse1
- Outcome
- phenylalanine ammonia lyase, peroxidase, and polyphenol oxidasee0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Key defense enzymes, including phenylalanine ammonia lyase, peroxidase, and polyphenol oxidase, showed significantly enhanced activities”
t0“grapevine”
e1“combined ANE and CHA0 applications”
e2“downy mildew in grapevines”
Claim · model-written summary
Combined applications elevated phenolics and hydrogen peroxide.
- Treatment
- combined ANE and CHA0 applicationse1
- Outcome
- levels of phenolics and hydrogen peroxidee0
- Direction
- elevatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“accompanied by elevated levels of phenolics and hydrogen peroxide.”
t0“grapevine”
e1“combined ANE and CHA0 applications”
e2“downy mildew in grapevines”
Claim · model-written summary
Combined treatment upregulated CHI, GLP2 and GLP7.
- Treatment
- the combinatione0
- Gene
- CHI , GLP2 and GLP7e0
- Outcome
- stress-responsive genese0
- Direction
- upregulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the combination significantly upregulated stress-responsive genes such as CHI , GLP2 and GLP7”
t0“grapevine”
Claim · model-written summary
Combined treatment upregulated LOX9, OSM1, and PR4.
- Treatment
- the combinatione1
- Gene
- LOX9 , OSM1 , and PR4e0
- Outcome
- jasmonic acid-responsive genese0
- Direction
- upregulatede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“jasmonic acid-responsive genes including LOX9 , OSM1 , and PR4”
t0“grapevine”
e1“the combination significantly upregulated”
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