TY - JOUR A1 - Grote, Jessica A1 - Krysciak, Dagmar A1 - Petersen, Katrin A1 - Güllert, Simon A1 - Schmeisser, Christel A1 - Förstner, Konrad U. A1 - Krishnan, Hari B. A1 - Schwalbe, Harald A1 - Kubatova, Nina A1 - Streit, Wolfgang R. T1 - The Absence of the N-acyl-homoserine-lactone Autoinducer Synthase Genes tral and ngrl Increases the Copy Number of the Symbiotic Plasmid in Sinorhizobium fredii NGR234 JF - Frontiers in Microbiology N2 - Plant-released flavonoids induce the transcription of symbiotic genes in rhizobia and one of the first bacterial responses is the synthesis of so called Nod factors. They are responsible for the initial root hair curling during onset of root nodule development. This signal exchange is believed to be essential for initiating the plant symbiosis with rhizobia affiliated with the Alphaproteobacteria. Here, we provide evidence that in the broad host range strain Sinorhizobium fredii NGR234 the complete lack of quorum sensing molecules results in an elevated copy number of its symbiotic plasmid (pNGR234a). This in turn triggers the expression of symbiotic genes and the production of Nod factors in the absence of plant signals. Therefore, increasing the copy number of specific plasmids could be a widespread mechanism of specialized bacterial populations to bridge gaps in signaling cascades. KW - Sinorhizobium fredii KW - plasmid copy number KW - plant symbioses KW - quorum sensing (QS) KW - RNA sequencing (RNA-Seq) Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-165185 VL - 7 IS - 1858 ER -