The plasmids pInhi_A227 and pInhi_B88 contain postsegregational killing systems (PSK) consisting of a typical operon with two small genes encoding a stable toxin and an unstable antitoxin [70]. Moreover, plasmid pInhi_B88 also contains a complete virB gene cluster of type IV secretion selleck chemical system, required for the formation of a transmembrane channel. However, the absence of the relaxase VirD2, which is necessary for the strand-specific DNA nicking at the origin of transfer (oriT), and the coupling protein VirD4 indicates that this plasmid is non-conjugative [71,72]. The RepA-I type replicon pInhi_D69 contains a complete rhamnose operon [73] and is dominated by genes required for polysaccharide biosynthesis. Table 6 Integrated Microbial Genome (IMG) locus tags of P.
inhibens DSM 16374T genes for the initiation of replication, toxin/antitoxin modules and two representatives of type IV secretion systems (T4SS) that are required for conjugation. As already indicated by the strong inhibitory activity of P. inhibens T5T [8] all 26 described genes involved in the production of TDA are present in the genome of this strain. As found for the P. inhibens strains DSM 17395 and DSM 24588, the key genes for TDA production tdaABCDEF (Inhi_3684 – _3688, Inhi_3701), paaZ2 (Inhi_3702) and a gene coding for a putative Na-dependent transporter (Inhi_3697) [3,74] are located on the 227 kb plasmid of T5T (Figure 3). The remaining 19 genes, containing genes of the phenylacetyl-CoA and assimilatory sulfate reduction pathways, are scattered over the chromosome as in the strains DSM 17395 and DSM 24588 [3].
Beside the tdaA gene, present on the 227 kb plasmid, we also found other genes involved in the regulation of TDA synthesis located on the chromosome, what is in agreement with Thole et al. (2012) and Berger et al. (2012) [3,75]. This includes the genes encoding transcriptional activator proteins (Inhi_2121; _2059; _0396) comparable with pgaR, iorR a transcriptional regulator (PGA1_c20730), a putative serine-protein kinase (Inhi_2265) and a putative signal peptide peptidase (Inhi_2227). Two complete prophages and an additional cluster coding for the production of gene transfer agents AV-951 (GTA) were found in the genome of strain T5T. The GTA gene cluster is equal in length and comprises the same genes (Inhi_0654 �C Inhi_0670) as the GTA clusters of the strains DSM 17395 and DSM 24588. The two prophages of strain T5T consist of 52 ORFs (prophage 1; ~37kb) and 63 ORFs (prophage 2; ~48kb), respectively. Strain DSM 17395 possesses two prophages, but for DSM 24588 no prophages were detected [3].