Abstract
Protection of plants against bacterial diseases still mainly relies on the use of chemical pesticides, which in Europe correspond essentially to copper-based compounds. However, recently plant diseases control is oriented towards a rational use of molecules and extracts, generally with natural origin, with lower intrinsic toxicity and a reduced negative environmental impact. In this work, polyphenolic extracts from vegetable no food/feed residues of typical Mediterranean crops, as Olea europaea, Cynara scolymus, and Vitis vinifera were obtained and their inhibitory activity on the Type Three Secretion System (TTSS) and the Quorum Sensing (QS) of the Gram-negative phytopathogenic bacterium Pseudomonas savastanoi pv. nerii strain Psn23 was assessed. Extract from green tea (Camellia sinensis) was used as a positive control. Collectively, the data obtained through gfp-promoter fusion system and real-time PCR show that all the polyphenolic extracts here studied have a high inhibitory activity on both the TTSS and QS of Psn23, without any depressing effect on bacterial viability. Extracts from green tea and grape seeds were shown to be the most active. Such activity was confirmed in planta by a strong reduction in the ability of Psn23 to develop hyperplastic galls on explants from adult oleander plants, as well as to elicit hypersensitive response on tobacco. By using a newly developed Congo red assay and an ELISA test, we demonstrated that the TTSS-targeted activity of these polyphenolic extracts also affects the TTSS pilus assembly. In consideration of the potential application of polyphenolic extracts in plant protection, the absence of any toxicity of these polyphenolic compounds was also assessed. A widely and evolutionary conserved molecular target such as Ca2+-ATPase, essential for the survival of any living organism, was used for the toxicity assessment.
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Claims 7
Claim · model-written summary
All polyphenolic extracts had a high inhibitory activity on both the TTSS and QS of Psn23.
- Taxon
- oleandere4
- Treatment
- polyphenolic extractse1
- Interactor
- Psn23e1pathogen
- Outcome
- inhibitory activity on both the TTSS and QSe1
- Direction
- highe1
Not reportedComparator
Verbatim
e1“all the polyphenolic extracts here studied have a high inhibitory activity on both the TTSS and QS of Psn23, without any depressing effect on bacterial viability”
e4“a strong reduction in the ability of Psn23 to develop hyperplastic galls on explants from adult oleander plants, as well as to elicit hypersensitive response on tobacco”
Claim · model-written summary
Extracts from green tea and grape seeds were the most active of the extracts.
- Taxon
- oleandere4
- Treatment
- Extracts from green tea and grape seedse3
- Outcome
- the most activee3
- Direction
- the most activee3
Not reportedComparator
Verbatim
e3“Extracts from green tea and grape seeds were shown to be the most active”
e4“a strong reduction in the ability of Psn23 to develop hyperplastic galls on explants from adult oleander plants, as well as to elicit hypersensitive response on tobacco”
Claim · model-written summary
The polyphenolic extracts strongly reduced the ability of Psn23 to develop hyperplastic galls on explants from adult oleander plants.
- Taxon
- oleandere4
- Treatment
- polyphenolic extractse1
- Interactor
- Psn23e4pathogen
- Outcome
- to develop hyperplastic gallse4
- Direction
- strong reductione4
Not reportedComparator
Verbatim
e1“all the polyphenolic extracts here studied have a high inhibitory activity on both the TTSS and QS of Psn23, without any depressing effect on bacterial viability”
e4“a strong reduction in the ability of Psn23 to develop hyperplastic galls on explants from adult oleander plants, as well as to elicit hypersensitive response on tobacco”
Claim · model-written summary
The polyphenolic extracts reduced the ability of Psn23 to elicit hypersensitive response on tobacco.
- Taxon
- tobacco
Nicotiana tabacume4 - Treatment
- polyphenolic extractse1
- Interactor
- Psn23e4pathogen
- Outcome
- to elicit hypersensitive responsee4
- Direction
- strong reductione4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“all the polyphenolic extracts here studied have a high inhibitory activity on both the TTSS and QS of Psn23, without any depressing effect on bacterial viability”
e4“a strong reduction in the ability of Psn23 to develop hyperplastic galls on explants from adult oleander plants, as well as to elicit hypersensitive response on tobacco”
Claim · model-written summary
The TTSS-targeted activity of the polyphenolic extracts affects TTSS pilus assembly.
Not reportedComparatorDirection
Verbatim
e4“a strong reduction in the ability of Psn23 to develop hyperplastic galls on explants from adult oleander plants, as well as to elicit hypersensitive response on tobacco”
e5“the TTSS-targeted activity of these polyphenolic extracts also affects the TTSS pilus assembly”
Claim · model-written summary
The polyphenolic compounds showed no toxicity in the assessment.
Verbatim
e4“a strong reduction in the ability of Psn23 to develop hyperplastic galls on explants from adult oleander plants, as well as to elicit hypersensitive response on tobacco”
e6“the absence of any toxicity of these polyphenolic compounds was also assessed”
Claim · model-written summary
The polyphenolic extracts had no depressing effect on bacterial viability of Psn23.
- Taxon
- oleandere4
- Treatment
- polyphenolic extractse1
- Interactor
- Psn23e1pathogen
- Outcome
- bacterial viabilitye1
- Direction
- without any depressing effecte1
Not reportedComparator
Verbatim
e1“all the polyphenolic extracts here studied have a high inhibitory activity on both the TTSS and QS of Psn23, without any depressing effect on bacterial viability”
e4“a strong reduction in the ability of Psn23 to develop hyperplastic galls on explants from adult oleander plants, as well as to elicit hypersensitive response on tobacco”
The same questions in other papers
botanical · growth · Nerium oleander (common oleander)Positive and negative results
1 in the opposite direction
- positive
botanical · disease · Nicotiana tabacum (tobacco)Positive and negative results
12 papers in the same direction as this paper · 4 in the opposite direction
- no effect
- negative
- no effect
13 papers more in this group
See all 17 papers →botanical · pest · Nerium oleander (common oleander)Results agree
2 papers in the same direction as this paper
- positive
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.