INDIRECT ELISA FOR QUANTITATIVE ASSESSMENT OF FUSARIUM SPP IN RYE

Specific antibodies against Fusarium spp. were produced by immunizatio n of rabbits with total soluble protein fractions of F. culmorum obtai ned from shake and still cultures. An indirect ELISA was developed for the detection of the pachogen in stem bases of infected rye (Secale c ereale L.) plants. The polyclonal antibodies of both antisera detected F. culmorum, F. graminearum, and F. avenaceum with high sensitivity, but could not differentiate among these Fusarium species. Cross-reacti ons with Pseudo-cercosporella spp., Microdochium nivale, Drechslera so rokiniana, Ceratobasidium cereale and rye tissue were not significant. The antibodies could be used for specific identification of Fusarium spp. in plants infected by several foot rot pathogens simultaneously. However, quantitative assessment of Fusarium spp. in infected plants w as only possible with antibodies against the still culture protein fra ction. In 1990 and 1991, eight and twelve inbred lines of rye, respect ively, were artificially inoculated with F. culmorum in the field. Sig nificant genotypic differentiation was detected when stem bases were e xamined by ELISA. Close correlations (r = 0.65-0.89) occurred between visual disease ratings and ELISA absorbance values.