IMMUNODETECTION OF ELICITINS FROM PHYTOPHTHORA SPP USING MONOCLONAL-ANTIBODIES

Ten monoclonal antibodies were selected from mice immunized with a hig hly purified elicitin secreted by Phytophthora cryptogea, termed crypt ogein. These antibodies could be classified into five groups according to their cross-reactivity to heterologous elicitins from other Phytop hthora species, from strict specificity (reacting solely with cryptoge in) to broad reactivity (reacting with all four elicitins under study) . When examined on BIA core (a real-time biospecific interaction analy ser), these monoclonal antibodies were found to recognize at least thr ee different epitopes on the cryptogein molecule. Their use in eliciti n detection and quantification was optimized in several ELISA protocol s. A mixed monoclonal-polyclonal antibody, indirect DAS-ELISA procedur e detected as little as 20 pg of purified elicitin per well (100 mu l) . The four elicitins could be detected with the aid of one of couple o f polyvalent reagents, whilst each one could be detected separately us ing appropriate monoclonal antibodies. These protocols have been used to detect elicitins secreted by Phytophthora spp. into culture medium as well as in planta following plant inoculation.