N-Acylhomoserine lactone quorum-sensing signalling in antagonistic phenazine-producing Pseudomonas isolates from the red cocoyam rhizosphere

De Maeyer, K.; D'aes, J.; Hua, G.K.H.; Perneel, M.; Vanhaecke, L.; Noppe, H.; Höfte, M.

doi:10.1099/MIC.0.043125-0

Title

N-Acylhomoserine lactone quorum-sensing signalling in antagonistic phenazine-producing Pseudomonas isolates from the red cocoyam rhizosphere

Author

De Maeyer, K.

D'aes, J.

Hua, G.K.H.

Perneel, M.

Vanhaecke, L.

Noppe, H.

Höfte, M.

Abstract

Forty fluorescent Pseudomonas strains isolated from white and red cocoyam roots were tested for their ability to synthesize N-acyl-L-homoserine lactones (acyl-HSLs). Remarkably, only isolates from the red cocoyam rhizosphere that were antagonistic against the cocoyam root rot pathogen Pythium myriotylum and synthesized phenazine antibiotics produced acyl-HSLs. This supports the assumption that acyl-HSL production is related to the antagonistic activity of the strains. After detection, the signal molecules were identified through TLC-overlay and liquid chromatography-multiple MS (LC-MS/MS) analysis. In our representative strain, Pseudomonas CMR12a, production of the signal molecules could be assigned to two quorum-sensing (QS) systems. The first one is the QS system for phenazine production, PhzI/PhzR, which seemed to be well conserved, since it was genetically organized in the same way as in the well-described phenazine-producing Pseudomonas strains Pseudomonas fluorescens 2-79, Pseudomonas chlororaphis PCL1391 and Pseudomonas aureofaciens 30-84. The newly characterized genes cmrI and cmrR make up the second QS system of CMR12a, under the control of the uncommon N-3-hydroxy-dodecanoyl-homoserine lactone (3-OH-C12-HSL) and with low similarity to other Pseudomonas QS systems. No clear function could yet be assigned to the CmrI/CmrR system, although it contributes to the biocontrol capability of CMR12a. Both the PhzI/PhzR and CmrI/CmrR systems are controlled by the GacS/GacA two-component regulatory system.

Language

English

Source (journal)

Microbiology / Society for General Microbiology; Microbiology Society [Londen] - London, 1994, currens

Publication

London : 2011

ISSN

1350-0872 [print]

1465-2080 [online]

DOI

10.1099/MIC.0.043125-0

Volume/pages