Pseudomonas syringae

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Pseudomonas syringae
Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Gamma Proteobacteria
Order: Pseudomonadales
Family: Pseudomonadaceae
Genus: Pseudomonas
Species: P. syringae
Binomial name
Pseudomonas syringae
Van Hall, 1904
Type strain
ATCC 19310

CCUG 14279
CFBP 1392
CIP 106698
ICMP 3023
LMG 1247
NCAIM B.01398
NRRL B-1631


P. s. pv. aceris
P. s. pv. aptata
P. s. pv. atrofaciens
P. s. pv. dysoxylis
P. s. pv. japonica
P. s. pv. lapsa
P. s. pv. panici
P. s. pv. papulans
P. s. pv. pisi
P. s. pv. syringae

Pseudomonas syringae is a rod shaped, Gram-negative bacterium, with polar flagella. It is a member of the Pseudomonas genus, and based on 16S rRNA analysis, P. syringae has been placed in the P. syringae group[1]. It is a plant pathogen which can infect a wide range of plant species, and exists as over 50 different pathovars. Many of these pathovars were once considered to be individual species within the Pseudomonas genus, but molecular biology techniques such as DNA hybridization have shown these to in fact all be part of the P. syringae species. It is named after the lilac tree (Syringa vulgaris), from which it was first isolated[2].

P. syringae tests negative for arginine dihydrolase and oxidase activity, and forms the polymer levan on sucrose nutrient agar. It is known to secrete the lipodepsinonapeptide plant toxin syringomycin,[3] and it owes its yellow fluorescent appearance when cultured in vitro on King's B medium to production of the siderophore pyoverdin.[4] It also demonstrates ice nucleating properties.[5]


Disease by P. syringae tends to be favoured by wet, cool conditions - optimum temperatures for disease tend to be around 12–25°C, although this can vary according to the pathovar involved. The bacteria tend to be seed borne, and are dispersed between plants via rain splash.[6].

Although it is a plant pathogen, it can also live as a saprophyte in the phyllosphere when conditions are not favourable for disease.[7] Some saprophytic strains of P. syringae have been used as biocontrol agents against post-harvest rots[8].


Following ribotypical analysis several pathovars of Pseudomonas syringae were incorporated into other species[9] (see P. amygdali, 'P. tomato', P. coronafaciens, P. avellanae, 'P. helianthi', P. tremae, P. cannabina, and P. viridiflava). The remaining pathovars are as follows:

Pseudomonas syringae pv. aceris attacks maple Acer species.

Pseudomonas syringae pv. aptata attacks beets Beta vulgaris.

Pseudomonas syringae pv. atrofaciens attacks wheat Triticum aestivum.

Pseudomonas syringae pv. dysoxylis attacks the kohekohe tree Dysoxylum spectabile.

Pseudomonas syringae pv. japonica attacks barley Hordeum vulgare.

Pseudomonas syringae pv. lapsa attacks wheat Triticum aestivum.

Pseudomonas syringae pv. panici attacks Panicum grass species.

Pseudomonas syringae pv. papulans attacks crabapple Malus sylvestris species.

Pseudomonas syringae pv. pisi attacks peas Pisum sativum.

Pseudomonas syringae pv. syringae attacks Syringa and Phaseolus species.

Note that Pseudomonas savastanoi was once considered a pathovar or sub-species of P. syringae, and in many places continues to be referred to as Pseudomonas syringae pv. savastanoi, although as a result of DNA-relatedness studies it has been instated as a new species[10]. It itself has three host-specific pathovars, fraxini which causes ash canker, nerii which attacks oleander and oleae which causes olive knot.

Genome sequencing projects

The genomes of several strains of P. syringae have been sequenced, including P. syringae pv. tomato DC3000, P. syringae pv. syringae B728a and P. syringae pv. phaseolicola 1448A.[11]

See Also


  1. Anzai; et al. (2000, Jul). "Phylogenetic affiliation of the pseudomonads based on 16S rRNA sequence". Int J Syst Evol Microbiol. 50 (Pt 4): 1563–89. PMID 10939664. Check date values in: |year= (help)
  2. Kreig N.R., Holt J.G. (eds). (1984) Bergey's Manual of Systematic Biology Baltimore: The Williams and Wilkins Co., pg. 141-199
  3. Scholz-Schroeder B.K., Soule J.D., and Gross D. C. 2003. The sypA, sypS, and sypC synthetase genes encode twenty-two modules involved in the nonribosomal peptide synthesis of syringopeptin by Pseudomonas syringae pv. syringae B301D. Molecular Plant-Microbe Interactions 16:271-80 PMID 12744455
  4. Cody and Gross (1987) Characterization of Pyoverdinpss, the Fluorescent Siderophore Produced by Pseudomonas syringae pv. syringae. Applied Environmental Microbiology 53(5): 928–934 PMID 16347352
  5. Maki, Galyan, Chang-Chien and Caldwell (1974) Ice Nucleation Induced by Pseudomonas syringae. Applied Environmental Microbiology 28(3): 456-459 PMID 4371331
  6. Hirano, S. S. and C. D. Upper (1990) Population biology and epidemiology of Pseudomonas syringae Annual Reviews in Phytopathology 28:155-177
  7. Hirano and Upper (2000) Bacteria in the Leaf Ecosystem with Emphasis on Pseudomonas syringae — a Pathogen, Ice Nucleus, and Epiphyte. Microbiology and Molecular Biology Reviews 64 624-653. PMID 10974129
  8. Janisiewicz, W. J. and Marchi, A. 1992. Control of storage rots on various pear cultivars with saprophytic strain of Pseudomonas syringae. Plant Disease, 76: 555-560
  9. Gardan; et al. (1999 Apr). "DNA relatedness among the pathovars of Pseudomonas syringae and description of Pseudomonas tremae sp. nov. and Pseudomonas cannabina sp. nov. (ex Sutic and Dowson 1959)". Int J Syst Bacteriol. 49 (Pt 2): 469–78. PMID 10319466. Check date values in: |year= (help)
  10. Gardan; et al. (1999 Apr). "DNA relatedness among the pathovars of Pseudomonas syringae and description of Pseudomonas tremae sp. nov. and Pseudomonas cannabina sp. nov. (ex Sutic and Dowson 1959)". Int J Syst Bacteriol. 49 (Pt 2): 469–78. PMID 10319466. Check date values in: |year= (help)

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