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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.

No MeSH data available.


Related in: MedlinePlus

Current measurements on SR vesicles adsorbed on a SSM.Current signals induced by 100 μM ATP concentration jumps in the presence of 10 μM Ca2+free and in the absence (black curve, control measurement) or in the presence of CuCl2 (red curve) or of the polyphenolic compounds EGCG, catechin, oleuropein, hydroxytyrosol and chlorogenic acid (green curves).
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pone.0163357.g005: Current measurements on SR vesicles adsorbed on a SSM.Current signals induced by 100 μM ATP concentration jumps in the presence of 10 μM Ca2+free and in the absence (black curve, control measurement) or in the presence of CuCl2 (red curve) or of the polyphenolic compounds EGCG, catechin, oleuropein, hydroxytyrosol and chlorogenic acid (green curves).

Mentions: To investigate the interaction of these polyphenolic compounds with SR Ca2+-ATPase and its possible inhibition, we performed current measurements on SR vesicles adsorbed on a SSM. The SSM technique allows direct measurements of charge displacements within the transport protein yielding valuable information about the ion transport mechanism [32,56,57]. The technique is also well suited for the analysis of inhibitor interactions with membrane transporters [33,58]. As shown in Fig 5, a current signal was observed following a 100 μM ATP concentration jump in the presence of CaCl2 (10 μM), taken as a control measurement. It is worth mentioning that the charge obtained by numerical integration of the ATP-induced current signal is attributed to an electrogenic event corresponding to translocation and release of bound Ca2+, after utilization of ATP [32,33,57].


Global Analysis of Type Three Secretion System and Quorum Sensing Inhibition of Pseudomonas savastanoi by Polyphenols Extracts from Vegetable Residues
Current measurements on SR vesicles adsorbed on a SSM.Current signals induced by 100 μM ATP concentration jumps in the presence of 10 μM Ca2+free and in the absence (black curve, control measurement) or in the presence of CuCl2 (red curve) or of the polyphenolic compounds EGCG, catechin, oleuropein, hydroxytyrosol and chlorogenic acid (green curves).
© Copyright Policy
Related In: Results  -  Collection

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

pone.0163357.g005: Current measurements on SR vesicles adsorbed on a SSM.Current signals induced by 100 μM ATP concentration jumps in the presence of 10 μM Ca2+free and in the absence (black curve, control measurement) or in the presence of CuCl2 (red curve) or of the polyphenolic compounds EGCG, catechin, oleuropein, hydroxytyrosol and chlorogenic acid (green curves).
Mentions: To investigate the interaction of these polyphenolic compounds with SR Ca2+-ATPase and its possible inhibition, we performed current measurements on SR vesicles adsorbed on a SSM. The SSM technique allows direct measurements of charge displacements within the transport protein yielding valuable information about the ion transport mechanism [32,56,57]. The technique is also well suited for the analysis of inhibitor interactions with membrane transporters [33,58]. As shown in Fig 5, a current signal was observed following a 100 μM ATP concentration jump in the presence of CaCl2 (10 μM), taken as a control measurement. It is worth mentioning that the charge obtained by numerical integration of the ATP-induced current signal is attributed to an electrogenic event corresponding to translocation and release of bound Ca2+, after utilization of ATP [32,33,57].

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