In this study, we investigated selleck chemical the presence of Tn6188 within the genus Listeria spp. Our screening indicates that the distribution of Tn6188 may be limited to L. monocytogenes.

We confirm that QacH is responsible for the observed increase in tolerance by complementation of a qacH deletion mutant and introducing qacH in a Tn6188 negative strain. We investigated the transporter’s substrate spectrum by determining minimal inhibitory concentrations (MICs) and showed that QacH also confers higher tolerance towards other QACs and ethidium bromide (EtBr). This result was supported by increased expression of qacH in the presence of the various substrates as determined by quantitative reverse transcriptase PCR (qRT-PCR). In addition, we detected expression of a Tn6188 transposase gene and circular forms selleckchem of Tn6188, suggesting activity and possible transfer of this transposon. “
“A 530-kb megaplasmid pPag3 contributing 10.8% of the total genome of Pantoea vagans biocontrol strain C9-1

was sequenced. A rare nonpigmented variant C9-1W was obtained and shown to have lost pPag3, but retained all other plasmids (pPag1, pPag2). Phenotypic characterization of the variant confirmed the function of several annotated genes that may influence ecological fitness and efficacy. Metabolic profiling revealed important plasmid-based carbon utilization phenotypes. Plasmid loss resulted in thiamine auxotrophy, absence of carotenoid pigmentation, desferrioxamine diffusible siderophore biosynthesis, inherent ampicillin resistance and expression of AI-1 quorum-sensing signaling. This confirmed the functional expression of the corresponding genes located on pPag3 in P. vagans. Pantoea is a diverse genus, with most species considered to be ubiquitous plant epiphytes and often isolated from a wide range Sclareol of other environmental habitats (e.g., soil, water,

insect/animal gut and clinical samples). Some plant isolates have demonstrated strong beneficial activity as biological control agents for pre- and postharvest fungal and bacterial diseases (Braun-Kiewnick et al., 2000; Bonaterra et al., 2005; Francés et al., 2006). The type species, Pantoea agglomerans, has undergone extensive taxonomic rearrangement emerging from the Enterobacter agglomerans–Erwinia herbicola complex (Ewing & Fife, 1972; Rezzonico et al., 2009). Recently, several closely related species, such as P. vagans, have been newly described based on molecular analysis (e.g., multilocus sequence analysis, DNA–DNA hybridization) (Brady et al., 2008, 2009; Rezzonico et al., 2009). Strain C9-1 is an important biocontrol agent (Ishimaru et al., 1988; Johnson & Stockwell, 1998) that is registered in the United States and Canada as Blight Ban C9-1 (NuFarms America).