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N-acyl homoserine lactones in diverse Pectobacterium and Dickeya plant pathogens: diversity, abundance, and involvement in virulence.

Crépin A, Beury-Cirou A, Barbey C, Farmer C, Hélias V, Burini JF, Faure D, Latour X - Sensors (Basel) (2012)

Bottom Line: All the NAHSL-lactonase expressing strains produced a lower amount of NAHSLs as compared to those harboring the empty vector.This work highlights that quorum sensing similarly contributed to virulence in most of the tested Pectobacterium and Dickeya, even the strains had been isolated recently or during the past decades.Thus, these key regulatory-molecules appear as credible targets for developing anti-virulence strategies against these plant pathogens.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen EA 4312, IUT Evreux, Evreux, France. alexandre.crepin@etu.univ-rouen.fr

ABSTRACT
Soft-rot bacteria Pectobacterium and Dickeya use N-acyl homoserine lactones (NAHSLs) as diffusible signals for coordinating quorum sensing communication. The production of NAHSLs was investigated in a set of reference strains and recently-collected isolates, which belong to six species and share the ability to infect the potato host plant. All the pathogens produced different NAHSLs, among which the 3-oxo-hexanoyl- and the 3-oxo-octanoyl-L-homoserine lactones represent at least 90% of total produced NAHSL-amounts. The level of NAHSLs varied from 0.6 to 2 pg/cfu. The involvement of NAHSLs in tuber maceration was investigated by electroporating a quorum quenching vector in each of the bacterial pathogen strains. All the NAHSL-lactonase expressing strains produced a lower amount of NAHSLs as compared to those harboring the empty vector. Moreover, all except Dickeya dadantii 3937 induced a lower level of symptoms in potato tuber assay. Noticeably, aggressiveness appeared to be independent of both nature and amount of produced signals. This work highlights that quorum sensing similarly contributed to virulence in most of the tested Pectobacterium and Dickeya, even the strains had been isolated recently or during the past decades. Thus, these key regulatory-molecules appear as credible targets for developing anti-virulence strategies against these plant pathogens.

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Involvement of NAHSLs in the virulence symptoms on potato tubers.Each tuber of Solanum tuberosum var. Allians was inoculated with pathogens harboring the empty vector p6010 or its lactonase AttM-encoding derivative pMIR102. Symptoms were observed five days post-infection and compared using the Mann and Whitney test (α = 0.05). Asterisks indicate statistical differences between symptoms in bacterial derivatives harboring empty and lactonase-expressing vectors. Legend: NS, non-significant.
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f3-sensors-12-03484: Involvement of NAHSLs in the virulence symptoms on potato tubers.Each tuber of Solanum tuberosum var. Allians was inoculated with pathogens harboring the empty vector p6010 or its lactonase AttM-encoding derivative pMIR102. Symptoms were observed five days post-infection and compared using the Mann and Whitney test (α = 0.05). Asterisks indicate statistical differences between symptoms in bacterial derivatives harboring empty and lactonase-expressing vectors. Legend: NS, non-significant.

Mentions: We used a quorum quenching approach to evaluate the involvement of NAHSLs in virulence of the Pectobacterium and Dickeya strains. The occlusion of QS signals in the pathogens was based on the introduction of a plasmid carrying a NAHSL-lactonase gene attM into each of the twelve studied phytopathogens. The attM gene belongs to the attKLM operon located on the At plasmid from Agrobacterium tumefaciens, which is involved in degradation of γ-butyrolactone, γ-hydroxybutyrate and NAHSLs [29,46,47]. All strains harboring the empty vector p6010 were able to induce tissue maceration five days after potato tuber inoculation (Figure 3). Overall, recent isolates were not more virulent than the reference strains isolated several years before. Symptom severity was variable between Pectobacterium and Dickeya genera and within Pectobacterium species and Dickeya genus. For P. atrosepticum species, moderate and strong macerations were detected in 10, 80, 10 and 90% of tubers infected by P. atrosepticum 1526, 6276, 100T and RNS 08.30.1A, respectively. Interestingly, the two P. atrosepticum 100T and RNS 08.30.1A shared the same NAHSL production profile with similar amounts for each NAHSL molecule. Moreover, P. atrosepticum RNS 08.30.1A exhibited a similar aggressiveness profile to D. dadantii 3937, even if their NAHSL production patterns were different. These observations revealed that symptom severity does not seem to be related to both nature and amount of NAHSL species.


N-acyl homoserine lactones in diverse Pectobacterium and Dickeya plant pathogens: diversity, abundance, and involvement in virulence.

Crépin A, Beury-Cirou A, Barbey C, Farmer C, Hélias V, Burini JF, Faure D, Latour X - Sensors (Basel) (2012)

Involvement of NAHSLs in the virulence symptoms on potato tubers.Each tuber of Solanum tuberosum var. Allians was inoculated with pathogens harboring the empty vector p6010 or its lactonase AttM-encoding derivative pMIR102. Symptoms were observed five days post-infection and compared using the Mann and Whitney test (α = 0.05). Asterisks indicate statistical differences between symptoms in bacterial derivatives harboring empty and lactonase-expressing vectors. Legend: NS, non-significant.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376598&req=5

f3-sensors-12-03484: Involvement of NAHSLs in the virulence symptoms on potato tubers.Each tuber of Solanum tuberosum var. Allians was inoculated with pathogens harboring the empty vector p6010 or its lactonase AttM-encoding derivative pMIR102. Symptoms were observed five days post-infection and compared using the Mann and Whitney test (α = 0.05). Asterisks indicate statistical differences between symptoms in bacterial derivatives harboring empty and lactonase-expressing vectors. Legend: NS, non-significant.
Mentions: We used a quorum quenching approach to evaluate the involvement of NAHSLs in virulence of the Pectobacterium and Dickeya strains. The occlusion of QS signals in the pathogens was based on the introduction of a plasmid carrying a NAHSL-lactonase gene attM into each of the twelve studied phytopathogens. The attM gene belongs to the attKLM operon located on the At plasmid from Agrobacterium tumefaciens, which is involved in degradation of γ-butyrolactone, γ-hydroxybutyrate and NAHSLs [29,46,47]. All strains harboring the empty vector p6010 were able to induce tissue maceration five days after potato tuber inoculation (Figure 3). Overall, recent isolates were not more virulent than the reference strains isolated several years before. Symptom severity was variable between Pectobacterium and Dickeya genera and within Pectobacterium species and Dickeya genus. For P. atrosepticum species, moderate and strong macerations were detected in 10, 80, 10 and 90% of tubers infected by P. atrosepticum 1526, 6276, 100T and RNS 08.30.1A, respectively. Interestingly, the two P. atrosepticum 100T and RNS 08.30.1A shared the same NAHSL production profile with similar amounts for each NAHSL molecule. Moreover, P. atrosepticum RNS 08.30.1A exhibited a similar aggressiveness profile to D. dadantii 3937, even if their NAHSL production patterns were different. These observations revealed that symptom severity does not seem to be related to both nature and amount of NAHSL species.

Bottom Line: All the NAHSL-lactonase expressing strains produced a lower amount of NAHSLs as compared to those harboring the empty vector.This work highlights that quorum sensing similarly contributed to virulence in most of the tested Pectobacterium and Dickeya, even the strains had been isolated recently or during the past decades.Thus, these key regulatory-molecules appear as credible targets for developing anti-virulence strategies against these plant pathogens.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen EA 4312, IUT Evreux, Evreux, France. alexandre.crepin@etu.univ-rouen.fr

ABSTRACT
Soft-rot bacteria Pectobacterium and Dickeya use N-acyl homoserine lactones (NAHSLs) as diffusible signals for coordinating quorum sensing communication. The production of NAHSLs was investigated in a set of reference strains and recently-collected isolates, which belong to six species and share the ability to infect the potato host plant. All the pathogens produced different NAHSLs, among which the 3-oxo-hexanoyl- and the 3-oxo-octanoyl-L-homoserine lactones represent at least 90% of total produced NAHSL-amounts. The level of NAHSLs varied from 0.6 to 2 pg/cfu. The involvement of NAHSLs in tuber maceration was investigated by electroporating a quorum quenching vector in each of the bacterial pathogen strains. All the NAHSL-lactonase expressing strains produced a lower amount of NAHSLs as compared to those harboring the empty vector. Moreover, all except Dickeya dadantii 3937 induced a lower level of symptoms in potato tuber assay. Noticeably, aggressiveness appeared to be independent of both nature and amount of produced signals. This work highlights that quorum sensing similarly contributed to virulence in most of the tested Pectobacterium and Dickeya, even the strains had been isolated recently or during the past decades. Thus, these key regulatory-molecules appear as credible targets for developing anti-virulence strategies against these plant pathogens.

Show MeSH
Related in: MedlinePlus