Toxin Production by Pseudomonas syringae pv. syringae: Correlation between Production of Toxin and Strain Host

Division of Horticulture and Processing, Department of Scientific and Industrial Research, Mt Albert Research Centre, Private Bag, Auckland, New Zealand ABSTRACT SUMMARY: The production by a number of strains of Pseudomonas syringae pv. syringae of compounds that inhibit the growth of Escherichia coli is reported. A high proportion of P. syringae pv. syringae strains from Syringa vulgaris and Citrus spp. produced the compounds responsible for this effect, whereas the proportion of producers amongst strains from Phaseolus spp., Prunus spp. or Pyrus communis was low, and amongst strains from Allium spp., Pisum sativum or Sorghum spp. was zero. This specificity in production may be a useful taxonomic feature. The inhibition of E. coli was prevented non-specifically by several basic amino acids, but not by the tripeptide triglycine, indicating that the compound may enter E. coli by the basic amino acid uptake system. There is no obvious relationship between this toxin and phaseolotoxin, syringomycin or syringotoxin.