Cross-reactive Antigens between Xanthomonas campestris pv. citri Pathotypes and Citrus Species

Cross-reactive antigens were detected in crude and semi-purified preparations from acetone powder of Citrus aurantifolia and Citrus sinensis leaves with antisera to Xanthomonas campestris pv. citri pathotypes A and C by DAS-ELISA. Antiserum to X. campestris pv. citri pathotype C revealed an antigenic disparity between C. aurantifolia (susceptible host to pathotype C) and C. sinensis (resistant host to pathotype C) whereas antiserum to X, campestris pv. citri pathotype A did not reveal any antigenic disparity between these hosts, both susceptible to pathotype A. The occurrence of “key” cross-reactive antigens in Citrus species and X. campestris pv. citri and their possible involvement in such interaction are discussed.