VIEW ARTICLE

Techniques

Use of Direct and Indirect Immunofluorescence Tests for Identification of Xanthomonas campestris. N. W. Schaad, Associate Professor, Department of Plant Pathology, University of Georgia, Georgia Experiment Station, Experiment, GA 30212; Phytopathology 68:249-252. Accepted for publication 7 July 1977. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-249.

A comparison was made between direct and indirect immunofluorescence (IF) for rapid identification of Xanthomonas campestris. Eighteen strains of X. campestris, five of X. vesicatoria, nine of Xanthomonas spp., five of nonidentified yellow-pigmented bacteria, one of Escherichia coli, and one of Pseudomonas syringae were tested. For direct IF, cells were stained with fluorescein isothiocyanate (FITC)-conjugated γ globulin to bacterial ribosomes. For indirect IF, bacterial cells were treated with antiserum or γ globulin to ribosomes and stained with FITC-conjugated antirabbit globulin. The stained cells were observed by fluorescence microscopy. All strains of X. campestris tested by indirect IF were positive, and only X. vesicatoria cross-reacted with X. campestris. It is concluded that indirect IF using antiserum to ribosomes is a useful method for quick identification of X. campestris.