Trial for rapid identification of pathogens from blasted pear blossoms and rotted radish leaves by the direct colony TLC and whole cellular fatty acid analysis

Rapid identification of phytopathogenic bacteria isolated from blasted pear blossoms and rotted radish leaves was tried by the direct colony TLC and whole cellular fatty acid analysis. All the 22 reference strains of fluorescent pseudomonads exhibited similar chromatograms with those of the pear and radish strains at the direct colony TLC. A dendrogram of strains based on fatty acid compositions showed that all pathovars of P. syringae, P. viridiflava and the pear and radish strains were closely related with lauric acid and palmitoleic acid as their major fatty acids. On the other hand, P. marginalis, P. fluorescens and P. aeruginosa predominantly containing an unidentified fatty acid, were clustered separately. The results of the direct colony TLC and fatty acid analysis suggested that the pear and radish strains belonged to P. syringae or P. viridiflava. Physiological and biochemical tests of the pear and radish strains confirmed that pear and radish strains were P. syringae and P. viridiflava, respectively. The direct colony TLC and/or whole cellular fatty acid analysis in combination with some selected physiological and biochemical tests will be convenient and practical approach for rapid identification of phytopathogenic bacteria.