Infection-related surface proteins on conidia of the nematophagous fungus Drechmeria coniospora

The adhesion of conidia of Drechmeria coniospora to the nematode Panagrellu s redivivus was reduced after treatment of the conidia with Pronase E, or t he detergents sodium dodecyl sulphate (SDS) and dodecyltrimethylammonium br omide (DTAB) suggesting involvement of proteinaceous compounds in the adhes ion process. In the TEM the thick extracellular pad covering the adhesive b ud of the conidia was completely removed after treatment with Pronase E. Af ter treatment with SDS or DTAB the proteinaceous compounds appeared to be d issolved leaving mainly carbohydrates in the pad as observed on OsO4 withou t and OsO4 with Ruthenium red-stained material, respectively. The detergent extracts after SDS and DTAB treatments contained nine and seven peptides, respectively, with molecular masses in the range from 6 to 80 kDa on SDS-PA GE gels, and five biotinylated peptides were found in each extract, after b lotting to nitrocellulose membranes, indicating that these were surface pro teins. None of the detergent extracts was able to reduce adhesion of the co nidia after treatment of the nematodes. The detergent extracts contained pr otease- and phosphatase activity. The protease inhibitor, chymostatin, inhi bited infection of nematodes and growth of the conidia, suggesting the invo lvement of chymotrypsin-like proteases in the infection process. On gelatin -containing substrate gel electrophoresis two proteases were dearly chymost atin sensitive.