DETECTION OF THE ARBUSCULAR MYCORRHIZAL FUNGUS SCUTELLOSPORA-HETEROGAMA WITHIN ROOTS USING POLYCLONAL ANTISERA

The antigenic properties of the arbuscular mycorrhizal Scutellospora h eterogama (BEG 35) were studied to develop a serological method for de tecting the fungus in roots. Three polyclonal antisera were raised aga inst the combined soluble and particulate fraction of spores of S. het erogama (BEG 35) and used in serological tests. When the soluble fract ion of crushed spores was used as antigens in Ouchterlony double diffu sion tests, all these antisera showed a high degree of specificity for the homologous fungus. No crossreactivity was found with Glomus geosp orum, Acaulospora spp., Entrophospora colombiana, Gigaspora spp. or ot her Scutellospora spp. Immunostaining of Western blots using one of th e antisera was less specific but major cross-reactions were limited to fungi in Scutellospora, which all produced different banding patterns . This enabled immunostaining of Western blots to be used to detect an d discriminate S. heterogama (BEG 35) and a morphologically similar Sc utellospora sp. (BEG 40) in plant roots. There was no crossreaction wi th uncolonized roots. AU bands detected in extracts horn colonized roo ts corresponded to bands detected in spore extracts, but some addition al bands were unique to the spores. No significant reaction was observ ed with roots colonized by arbuscular mycorrhizal fungi outside the ge nus Scutellospora. The antiserum may thus be used to trade species of Scutellospora within plant roots.