Xanthomonas campestris pv. citri Detection and Identification by Enzyme-Linked Immunosorbent Assay. E. L. Civerolo, Fruit Laboratory, Horticultural Science Institute, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705. F. Fan, Fruit Laboratory, Horticultural Science Institute, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705. Plant Dis. 66:231-236. Accepted for publication 15 May 1981. 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, 1982. DOI: 10.1094/PD-66-231.

The double antibody sandwich enzyme-linked immunosorbent assay was evaluated for the specific detection and identification of Xanthomonas campestris pv. citri. Alkaline phosphatase conjugates were prepared with immunoglobulin partially purified by ammonium sulfate precipitation from antisera to intact, live X. c. pv. citri cells. X. c. pv. citri antigens were detected in heated (100 C for 30 min) cell suspensions containing 10³–10⁴ colony-forming units per milliliter. X. c. pv. citri was also detected by enzyme-linked immunosorbent assay when added to extracts of healthy grapefruit seedling leaves and in extracts of lesions from artificially inoculated leaves. No detectable reactions occurred with several other xanthomonad nomenspecies and one saprophytic bacterium. Positive reactions occurred with five of six X. campestris pv. manihotis strains using antiserum to an Asian (pathotype A) strain of X. c. pv. citri but not with antisera prepared against X. c. pv. citri strains from Argentina and Brazil.

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