Analysis of Draft Genome Resources of Thirty-Three Canadian Strains of Pseudomonas syringae pv. tomato Isolated Between 1992 and 2008 Reveals Achromobactin Virulence Cluster that Is Absent in the Reference Strain DC3000.

Abstract

Pseudomonas syringae pv. tomato is the causal agent of bacterial speck disease of field and greenhouse tomato plants. Only one Canadian whole genome sequence of this economically important pathogen is publicly available in NCBI GenBank. Here, we report 33 whole genome sequences of Canadian strains of P. syringae pv. tomato isolated in Ontario, Canada, between 1992 and 2008. The genome sequences exhibited average nucleotide identity values of 98.64-98.72 % with P. syringae pv. tomato ICMP 2844PT and DC3000, validating the taxonomic standing of these Canadian strains. The genome sizes ranged from 6.20-6.39 Mbp with G+C content of 58.6% and comprised 5,889-6,166 protein-coding sequences (CDSs). The strains had pan- and core-genomes of 6808 and 4,993 gene clusters, respectively. Genome mining of the strains for virulence factors identified typical adherence genes, proteins related to antiphagocytosis, secretion system apparatuses and effectors. Also, partial or complete achromobactin biosynthetic cluster and iron transport genes were identified in all the Canadian strains but absent in P. syringae pv. tomato DC3000 or ICMP 2844 (pathotype). These new whole genome data of Canadian strains of P. syringae pv. tomato could be useful resources in understanding the evolution of this pathogen.