SECRETION OF EXTRACELLULAR ENZYMES BY VERTICILLIUM-PSALLIOTAE TRESCHOW AND VERTICILLIUM-LECANII (ZIMM) VIEGAS DURING GROWTH ON UREDOSPORES OF THE SOYBEAN RUST FUNGUS (PHAKOPSORA-PACHYRHIZI SYD) IN LIQUID CULTURES

Two isolates of the mycoparasite Verticillium psalliotae grew rapidly in liquid cultures on autoclaved uredospores of the soybean rust fungus (Phakopsora pachyrhizi Syd.) as sole carbon source and secreted beta-1,3-glucanase, chitinase, and protease activities into the medium. One isolate of Verticillium lecanii grew slowly, failed to produce measurable chitinase activity and secreted lower specific activities of beta-1,3-glucanase and protease, compared with V. psalliotae. The tested isolates of V. psalliotae and V. lecanii produced comparable levels of lipolytic activity. Amylolytic activity was secreted by V. lecanii but not by V. psalliotae. The isolates of V. psalliotae and V. lecanii used in our experiments differed clearly in protein and protease pattern, determined by electrophoresis on polyacrylamide gels. The results indicate that the rapid growth of V. psalliotae on autoclaved uredospores in liquid culture and on uredosori is probably based primarily on nutrients made available to the mycoparasite by activities of beta-1,3-glucanases, chitinases and proteases.