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Global Analysis of Type Three Secretion System and Quorum Sensing Inhibition of Pseudomonas savastanoi by Polyphenols Extracts from Vegetable Residues

View Article: PubMed Central - PubMed

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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Effect of polyphenolic extracts on Congo red dye absorption of Psn23 bacterial cultures.Percentage of Congo red dye absorption of Psn23 bacterial cultures, grown in MM amended with the polyphenolic extracts VN, TV, FO or FC. The data were calculated according to the formula: [(Xunk−XΔhrpA) / (XWT−XΔhrpA)] *100 where XWT and XΔhrpA are the ratio OD490/OD600 for Psn23 and ΔhrpA respectively. The data represent the means ± SD of three replicates. All treatments are statistically significant (P <0.05).
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pone.0163357.g003: Effect of polyphenolic extracts on Congo red dye absorption of Psn23 bacterial cultures.Percentage of Congo red dye absorption of Psn23 bacterial cultures, grown in MM amended with the polyphenolic extracts VN, TV, FO or FC. The data were calculated according to the formula: [(Xunk−XΔhrpA) / (XWT−XΔhrpA)] *100 where XWT and XΔhrpA are the ratio OD490/OD600 for Psn23 and ΔhrpA respectively. The data represent the means ± SD of three replicates. All treatments are statistically significant (P <0.05).

Mentions: The data obtained show that VN and TV cause a reduction of the dye absorption by Psn23-treated cells, corresponding to 86% and 96%, respectively (Fig 3). In the case of FO and FC, the Congo red absorption was reduced to about 71% and 52%, respectively (Fig 3). Overall, such a decrease in Congo red binding to Psn23-treated cells in comparison to those untreated, indirectly demonstrates that these polyphenolic extracts, although with different effectiveness, compromise the correct assembly of the TTSS pilus.


Global Analysis of Type Three Secretion System and Quorum Sensing Inhibition of Pseudomonas savastanoi by Polyphenols Extracts from Vegetable Residues
Effect of polyphenolic extracts on Congo red dye absorption of Psn23 bacterial cultures.Percentage of Congo red dye absorption of Psn23 bacterial cultures, grown in MM amended with the polyphenolic extracts VN, TV, FO or FC. The data were calculated according to the formula: [(Xunk−XΔhrpA) / (XWT−XΔhrpA)] *100 where XWT and XΔhrpA are the ratio OD490/OD600 for Psn23 and ΔhrpA respectively. The data represent the means ± SD of three replicates. All treatments are statistically significant (P <0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036890&req=5

pone.0163357.g003: Effect of polyphenolic extracts on Congo red dye absorption of Psn23 bacterial cultures.Percentage of Congo red dye absorption of Psn23 bacterial cultures, grown in MM amended with the polyphenolic extracts VN, TV, FO or FC. The data were calculated according to the formula: [(Xunk−XΔhrpA) / (XWT−XΔhrpA)] *100 where XWT and XΔhrpA are the ratio OD490/OD600 for Psn23 and ΔhrpA respectively. The data represent the means ± SD of three replicates. All treatments are statistically significant (P <0.05).
Mentions: The data obtained show that VN and TV cause a reduction of the dye absorption by Psn23-treated cells, corresponding to 86% and 96%, respectively (Fig 3). In the case of FO and FC, the Congo red absorption was reduced to about 71% and 52%, respectively (Fig 3). Overall, such a decrease in Congo red binding to Psn23-treated cells in comparison to those untreated, indirectly demonstrates that these polyphenolic extracts, although with different effectiveness, compromise the correct assembly of the TTSS pilus.

View Article: PubMed Central - PubMed

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.

No MeSH data available.


Related in: MedlinePlus