Mycoparasitic species of Trichoderma produce lectins

Culture filtrates and mycelial extracts of two mycoparasitic Trichoderma species were tested for the presence of lectins, by haemagglutination with human and marsupial erythrocytes. In Trichoderma viride, haemagglutinating activity was present in both mycelial extracts and culture filtrate. While secreted lectins were only detected after 6 days of growth, the presence of mycelium-associated lectins was first noted in 3-day-old cultures. Agglutinating activity was also demonstrated in the mycelium of 6-, 9- and 13-day-old cultures of Trichoderma harzianum. In this species, however, lectins were not secreted. In all instances, haemagglutination was inhibited by N-acetylgalactosamine and related sugars. This is the first report on the occurrence of lectins in Trichoderma spp.