The Production of Antibiotics in Soil

Extracts of the coats of seeds inoculated with Trichoderma viride, Penicillium frequentans or P. gladioli and sown in soil contained antibiotics, identified by paper chromatography as gliotoxin, frequentin and gladiolic acid respectively. Three actinomycetes, Streptoniyces griseus, S. venezuelae and S. nureofaciens failed to produce an antibiotic in the coats of seeds sown in either John Innes potting compost or a calcareous soil. When uninoculated pea seeds were sown in a soil in which an unintroduced gliotoxin‐producing strain of Trichoderma viride was growing vigorously, gliotoxin was detected in the seed coats.