Variation at the common polysaccharide antigen locus drives lipopolysaccharide diversity within the Pseudomonas syringae species complex

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 Land 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.

Long read metagenomics, the next step?

“…Furthermore, many key ecological functions such as transporters, degradation of resilient compounds, virulence factors and many others are also found in these genomic regions [78,79]. That the long replacement GI4 do not assemble in the MED4 LRa MAG was to be expected given the high diversity of very polyclonal microbes such as Prochlorococcus [80] and the length of this specific fGI involved in the synthesis of the O-chain polysaccharide [81,82]. The presence of multiple (and long) versions of GI4 might disorient the assembler that has many possibilities to continue the contig.…”

Enhanced Recovery of Microbial Genes and Genomes From a Marine Water Column Using Long-Read Metagenomics

“…Furthermore, many key ecological functions such as transporters, degradation of resilient compounds, virulence factors, and many others are also found in these genomic regions Neuenschwander et al, 2018). That the long replacement GI4 does not assemble in the MED4 LRa MAG was to be expected given the high diversity of very polyclonal microbes such as Prochlorococcus (Kashtan et al, 2014) and the length of this specific fGI involved in the synthesis of the O-chain polysaccharide (Holt et al, 2020;Jayaraman et al, 2020). The presence of multiple (and long) versions of GI4 might disorient the assembler that has many possibilities to continue the contig.…”

A Comprehensive Overview of the Genes and Functions Required for Lettuce Infection by the Hemibiotrophic Phytopathogen Xanthomonas hortorum pv. vitians

“…vitians . A thorough comparison with other plant-pathogenic bacterial LPSs would be difficult because each bacterium has a specific set of genes involved in LPS biosynthesis ( 100 – 102 ). Yet, the accurate identification of the LPS biosynthesis genomic regions critical for in planta fitness of X. hortorum pv.…”