The distribution of genes into COGs functional categories is presented in Table 4. Table 3 Genome Statistics Figure 2 Graphical map of the chromosome. From research use only outside to the center: genes on forward strand (colored by COG categories), genes on reverse strand (colored by COG categories), RNA genes: tRNAs – green, rRNAs – red, other RNAs – black, GC content, and GC skew Table 4 Number of genes associated with the 25 general COG functional categories The genome contains a complete canonical type III secretion system and ten known effector proteins: AvrE1, HopAA1, HopI1, HopM1, HopAH1, HopAG1, HopAI1, HopAZ1, HopBA1, and HopZ3. Out of these ten, the first five are present in all other sequenced P. syringae strains, thereby constituting the effector core, whereas the latter five could be host-determinants for wheat.

That there is such a small number of effectors is not something unusual, and is seen in other strains of clade II [22]. In addition, there are two complete type VI secretion system gene clusters and nine putative effector proteins belonging to the VgrG and Hcp1 families. Pss B64 genome also encodes gene clusters for biosynthesis of four phytotoxin: syringomycin, syringopeptin, syringolin, and mangotoxin. All of the above-mentioned genome components have been previously demonstrated to be involved in virulence, epiphytic fitness of P. syringae, as well as in competition with other microbial species [7-10,57-59].

Additional identified virulence-associated traits are: exopolysaccharides alginate, Psl, and levan biosynthesis, surfactant syringofactin, type VI pili, large surface adhesins, siderophores pyoverdine and achromobactin, proteases and other secreted hydrolytic enzymes, RND-type transporters (including putative mexAB, mexCD, mexEF, and mexMN homologs [60,61]), all of which are found in other P. syringae strains. It is also notable that inaZ gene encoding ice-nucleation protein is truncated by a frameshift, thus making this strain ice-negative. The latter contradicts results of a previous study by Hwang and colleagues [16] in which Pss B64 has been identified to be ice-positive. This could be due to an assembly error, or the frameshift could have been introduced at a later point during propagation. Acknowledgements The authors would like to thank Dr. Daria Zhurina for her useful suggestions on the gap closure and the annotation procedures.

This project was supported by the Swiss National Science Foundation (31003A-134936) and the Foundation for Research in Science and the Humanities at the University of Zurich. Notes Abbreviations: Pss- Carfilzomib Pseudomonas syringae pathovar syringae Pto- Pseudomonas syringae pathovar tomato, Pph- Pseudomonas syringae pathovar phaseolicola, EPS- Exopolymeric substances, NRPS- non-ribosomal peptide synthetase, MLST- multilocus sequence typing
Figure 1 shows the phylogenetic neighborhood of P.