The rulB gene of plasmid pWW0 is a hotspot for the site‐specific insertion of integron‐like elements found in the chromosomes of environmental Pseudomonas fluorescens group bacteria |
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| Authors: | Glenn Rhodes Hester Bosma David Studholme Dawn L Arnold Robert W Jackson Roger W Pickup |
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| Institution: | 1. Centre for Ecology and Hydrology, Lancaster Environment Centre, , Lancaster, LA1?4AP UK;2. Rijksuniversiteit Groningen, , 9700 AB Groningen, The Netherlands;3. Geoffrey Pope Building, College of Life and Environmental Sciences, University of Exeter, , Exeter, EX4?4QD UK;4. Centre for Research in Biosciences, University of the West of England, , Bristol, BS16?1QY UK;5. School of Biological Sciences, University of Reading, , Reading, RG6?6UR UK;6. Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, , Lancaster, LA1?4YQ UK |
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| Abstract: | The rulAB operon of Pseudomonas spp. confers fitness traits on the host and has been suggested to be a hotspot for insertion of mobile elements that carry avirulence genes. Here, for the first time, we show that rulB on plasmid pWW0 is a hotspot for the active site‐specific integration of related integron‐like elements (ILEs) found in six environmental pseudomonads (strains FH1–FH6). Integration into rulB on pWW0 occurred at position 6488 generating a 3 bp direct repeat. ILEs from FH1 and FH5 were 9403 bp in length and contained eight open reading frames (ORFs), while the ILE from FH4 was 16 233 bp in length and contained 16 ORFs. In all three ILEs, the first 5.1 kb (containing ORFs 1–4) were structurally conserved and contained three predicted site‐specific recombinases/integrases and a tetR homologue. Downstream of these resided ORFs of the ‘variable side’ with structural and sequence similarity to those encoding survival traits on the fitness enhancing plasmid pGRT1 (ILEFH1 and ILEFH5) and the NR‐II virulence region of genomic island PAGI‐5 (ILEFH4). Collectively, these ILEs share features with the previously described type III protein secretion system effector ILEs and are considered important to host survival and transfer of fitness enhancing and (a)virulence genes between bacteria. |
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