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Variation at the common polysaccharide antigen locus drives lipopolysaccharide diversity within the Pseudomonas syringae species complex |
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| Authors: | Jay Jayaraman William T. Jones Dawn Harvey Lauren M. Hemara Honour C. McCann Minsoo Yoon Suzanne L. Warring Peter C. Fineran Carl H. Mesarich Matthew D. Templeton |
| Affiliation: | 1. Bioprotection Technologies, The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand Bioprotection Centre for Research Excellence, New Zealand;2. Bioprotection Technologies, The New Zealand Institute for Plant and Food Research Limited, Palmerston North, New Zealand;3. Bioprotection Technologies, The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand Bioprotection Centre for Research Excellence, New Zealand School of Biological Sciences, University of Auckland, New Zealand;4. Bioprotection Technologies, The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand;5. Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand;6. Bioprotection Centre for Research Excellence, New Zealand Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand;7. Bioprotection Centre for Research Excellence, New Zealand School of Agriculture and Environment, Massey University, Palmerston North, New Zealand |
| Abstract: | The common polysaccharide antigen (CPA) of the lipopolysaccharide (LPS) from Pseudomonas syringae is highly variable, but the genetic basis for this is poorly understood. We have characterized the CPA locus from P. syringae pv. actinidiae (Psa). This locus has genes for l - and d -rhamnose biosynthesis and an operon coding for ABC transporter subunits, a bifunctional glycosyltransferase and an o -methyltransferase. This operon is predicted to have a role in the transport, elongation and termination of the CPA oligosaccharide and is referred to as the TET operon. Two alleles of the TET operon were present in different biovars (BV) of Psa and lineages of the closely related pathovar P. syringae pv. actinidifoliorum. This allelic variation was reflected in the electrophoretic properties of purified LPS from the different isolates. Gene knockout of the TET operon allele from BV1 and replacement with that from BV3, demonstrated the link between the genetic locus and the biochemical properties of the LPS molecules in Psa. Sequence analysis of the TET operon from a range of P. syringae and P. viridiflava isolates displayed a phylogenetic history incongruent with core gene phylogeny but correlates with previously reported tailocin sensitivity, suggesting a functional relationship between LPS structure and tailocin susceptibility. |
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