RT Journal Article SR Electronic(1) A1 De Maeyer, K. A1 D'aes, J. A1 Hua, G. K. H. A1 Perneel, M. A1 Vanhaecke, L. A1 Noppe, H. A1 Höfte, M.YR 2011 T1 N-Acylhomoserine lactone quorum-sensing signalling in antagonistic phenazine-producing Pseudomonas isolates from the red cocoyam rhizosphere JF Microbiology, VO 157 IS 2 SP 459 OP 472 DO https://doi.org/10.1099/mic.0.043125-0 PB Microbiology Society, SN 1465-2080, AB 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., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.043125-0