CHITINOLYTIC ENZYMES OF PATHOGENIC AND ECTOMYCORRHIZAL FUNGI

Four ectomycorrhizal basidiomycetes (Boletinus cavipes, Paxillus invol utus, Suillus variegatus and Pisolithus tinctoritus), two pathogenic r oot-infecting basidiomycetes (Heterobasidion annosum and Armillaria os toyae) and the oomycete Phytophthora cinnamomi were screened for chiti nolytic activity in liquid culture. N-Acetylglucosaminidase, exo- and endo-chitinase activity were distinguished using fluorogenic 4-methylu mbelliferyl substrates. N-Acetylglucosaminidase was the predominant en zyme activity recorded: exochitinase was the predominant chitinase. Th e pathogenic basidiomycetes had higher specific activities against all substrates than the ectomycorrhizal fungi. There was considerable var iation in activity between the ectomycorrhizal isolates. P. cinnamomi showed N-acetylglucosaminidase activity only. In general, chitinolytic activities were highest when chitin was present in the growth medium and were repressed in the presence of glucose. Diammonium phosphate di d not repress chitinolytic activities.