MONOCLONAL-ANTIBODIES SPECIFIC FOR XANTHOMONAS-CAMPESTRIS BACTERIA PATHOGENIC ON WHEAT AND OTHER SMALL GRAINS, IN COMPARISON WITH POLYCLONAL ANTISERA

4 hybridoma cell lines (named F1-AA9-D9, F1-AB3-B6, F1-BC7-C1 and F2-C A7-F11) secreting monoclonal antibodies to Xanthomonas campestris pv. undulosa were produced by fusing splenocytes from immunized Lou rats w ith IR983F myeloma cells. Whole cells were used both as immunogen and as antigen in ELISA and indirect immunofluorescence tests. The monoclo nal antibodies produced reacted positively with X. c. pv. undulosa (38 strains), pv. translucens (3), pv. hordei (3), pv. cerealis (2) and p v. secalis (1). Strains from other pathovars (X. c. pv. arrhenatheri, pv. graminis, pv. manihotis, pv. oryzicola, pv. poae and pv. pruni) an d from other species (X. axonopodis, X. ampelina) and genus (Pseudomon as, Erwinia, Clavibacter, wheat saprophytic strains) gave a negative r eaction. In comparison, seven polyclonal rabbit antisera showed to be less specific: they reacted with unrelated X. campestris pathovars as well as with Pseudomonas strains. Nevertheless, the use of phenol-trea ted cells in Ouchterlony double immunodiffusion could reduce the effec t of cross-reaction for antisera. The detection of X. c. pv. undulosa by indirect immunofluorescence on infected wheat seed lots has already been applied with success.