Partial Characterization of Fimbriae of Xanthomonas campestris pv. hyacinthi. J. van Doorn. Bulb Research Centre, Department of Plant Quality, Postbus 85, 2160AB Lisse. P. M. Boonekamp(1) Boudega(2). (1) Bulb Research Centre, Department of Plant Quality, Postbus 85, 2160AB Lisse (2)Department of Molecular Microbiology, Vrije Univrsiteit, Postbus 7161, 1007 MC Amsterdam, Netherlands. MPMI 7:334-344. Accepted 5 January 1994. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1994.

Xanhthomonas campestris pv. hyacinthi is a plant-pathogenic bacterium that causes yellow disease in Hyacinthus. X c. pv.hyacinthi produces monopolarly attached fimbriae with a diameter of approximately 5 nm and a length of at least 6 (m. Fimbriae were purified by acid precipitation and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. No hemagglutinating activity of purified fimbriae was found when the fimbriae were tested with several types of etythocytes. The fimbrial protein subunit had a relative molecular mass of 17 kDa; an isoelectric point was found at pH4.1. Analysis of the N-terminal amino acid sequence of the fimbrial subunit indicated that X. c. pv. expresses type 4 fimbriae of X. c. pv. hyacinthi in immunogold electron microscopy and immunoblotting experiments. Immunofluorescence studies showed that X.c. pv. hyacinthi cells as well as purified native fimbriae were attached to stomata of hyacinth leaves, suggesting a role for these surface antigens in the first stages of yellow disease.