Azospirillum brasilense Az39, a model rhizobacterium with AHL quorum quenching capacity

Abstract

Aims

The aim of this research was to analyze the Quorum sensing (QS) and Quorum quenching (QQ) mechanisms based on N?acyl?L?homoserine lactones (AHLs) in A. brasilense Az39, a strain with remarkable capacity to benefit a wide range of crops under agronomic conditions.

Methods and Results

We performed an in silico and in vitro analysis of the quorum mechanisms in A. brasilense Az39. The results obtained in vitro using the reporter strains C. violaceum and A. tumefaciens and Liquid Chromatography coupled to Mass?Mass Spectrometry (LC?MS/MS) analysis showed that although Az39 does not produce AHL molecules, it is capable of degrading them by at least two hypothetical enzymes identified by bioinformatics approach, associated to the bacterial cell. In Az39 cultures supplemented with 500 nmol l?1 of the C3 unsubstituted AHLs (C4, C6, C8, C10, C12, C14), AHL levels were lower than in non?inoculated LB media controls. Similar results were observed upon addition of AHLs with hydroxy (OH?) and keto (oxo?) substitutions in carbon 3. These results not only demonstrate the ability of Az39 to degrade AHLs. They also show the wide spectrum of molecules that can be degraded by this bacterium.

Conclusions

Although A.brasilense Az39 is a silent bacterium unable to produce AHL signals, it is able to interrupt the communications between other bacteria and/or plants by a quorum quenching activity.

Citation

Gualpa, J., Lopez, G., Nievas, S., Coniglio, A., Halliday, N., Cámara, M., & Cassán, F. (2019). Azospirillum brasilense Az39, a model rhizobacterium with AHL quorum quenching capacity. Journal of Applied Microbiology, 126(6), 1850-1860. https://doi.org/10.1111/jam.14269

• Journal Article Type: Article
• Acceptance Date: Mar 24, 2019
• Online Publication Date: Mar 29, 2019
• Publication Date: 2019-06
• Deposit Date: Apr 1, 2019
• Publicly Available Date: Mar 30, 2020
• Journal: Journal of Applied Microbiology
• Print ISSN: 1364-5072
• Electronic ISSN: 1365-2672
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 126
• Issue: 6
• Pages: 1850-1860
• DOI: https://doi.org/10.1111/jam.14269
• Keywords: Bioproducts; Mechanism of action; Microbial physiology; Quorum sensing; Genomics
• Public URL: https://nottingham-repository.worktribe.com/output/1724001
• Publisher URL: https://onlinelibrary.wiley.com/doi/abs/10.1111/jam.14269
• Additional Information: This is the peer reviewed version of the following article: Gualpa, J. , Lopez, G. , Nievas, S. , Coniglio, A. , Halliday,, N. , Cámara, M. and Cassán, F. (2019), Azospirillum brasilense Az39, a model rhizobacterium with AHL quorum quenching capacity. J Appl Microbiol. , which has been published in final form at https://doi.org/10.1111/jam.14269; . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.