Currently, the species is divided into five phylogenetic clades based on MLST analysis. P. syringae pv. syringae (Pss) directly strains belong to group II within this nomenclature [22]. The basic characteristics of Pss B64 are summarized in Table 1, while its phylogenetic position is depicted in Figure 1. Table 1 Classification and the general features of P. syringae pv. syringae B64 according to the MIGS recommendations [23] Figure 1 Phylogenetic tree constructed using neighbor-joining method using MLST approach [40] and MEGA 5.10 software suit [41] with 1,000 bootstraps. The tree features the three completely sequenced P. syringae model strains Pto DC3000, Pss B728a, and Pph 1448A, … Pss B64 has similar physiological properties as other representatives of its genus.
It can grow in complex media such as LB [42] or King��s B [43], as well as in various defined minimal media: HSC [44], MG-agar [45], PMS [46], AB-agar [47], and SRMAF [48]. Even though the optimal growth temperature is 28��C, the bacterium can also replicate at 4��C. Growth is completely inhibited above 35��C. Pss B64 is capable of endophytic growth in the wheat leaf mesophyll, but does not seem to cause any symptoms unless a very high inoculation dose is applied. The bacterium has a weak resistance to ampicillin (25 mg/L) and chloramphenicol (10 mg/L). It is also possible to develop spontaneous rifampicin-resistant mutants. In addition, the genomic sequence predicts this strain to be polymyxin B insensitive due to presence of the arn gene cluster.
Genome sequencing information Genome project history The organism was selected for sequencing because it has been identified to have a syringolin biosynthesis gene cluster [49]. Syringolin is a proteasome inhibitor produced by some strains of pathovar syringae. As a consequence of proteasome inactivation a number of plant intracellular pathways are being inhibited, including the entire salicylic acid-dependent defense pathway, thus promoting the entry of bacteria into leaf tissue and subsequent endophytic growth [9]. Since up to now it has not been possible to establish an infection model for syringolin in the model plant Arabidopsis, it was decided to explore another common research target and one of the most important crop plants, bread wheat (Triticum aestivum).
The genome project has been deposited in the Genbank Database (ID 180994) and the genome sequence is available under accession number “type”:”entrez-nucleotide”,”attrs”:”text”:”ANZF00000000″,”term_id”:”440495896″,”term_text”:”ANZF00000000″ANZF00000000. The version described in this Drug_discovery paper is the first version, “type”:”entrez-nucleotide”,”attrs”:ANZF01000000. The details of the project are shown in Table 2. Table 2 Genome sequencing project information Growth conditions and DNA isolation P. syringae pv. syringae strain B64 was grown in 40 mL of LB medium at 28��C, 220 rpm until OD600 of ~1.0.