Parasitism and Nutrition of the Contact Mycoparasite Acladium Tenellum

Abstract

Acladium tenellum is a contact, biotrophic mycoparasite deficient for thiamine and biotin but not mycotrophein. Nine Deuteromycetes, of 31 fungi tested, were hosts for two isolates of A. tenellum. Hook-shaped contact cells that partially encircled but did not penetrate host hyphae were formed by the parasite on all hosts. Generally, parasitism had no visible effect on host hyphae or colony growth. The mycelium of Bispora sp., a host fungus, contained thiamine and biotin, suggesting growth of the parasite on certain fungi may depend on its ability to obtain these required nutrients from host mycelium. Carbon sources, glucose, mannose, and galactose supported optimal axenic growth of both A. tenellum isolates. Fructose and cellobiose, however, supported optimal growth of one isolate, but less than optimal of the second. Nitrogen sources, casein hydrolysate, alanine, asparagine, aspartic acid, glutamic acid, and glutamine supported optimal growth of both isolates.