Proteinase activity in mycorrhizal fungi

Abstract

SUMMARYThe ericoid mycorrhizal endophyte, Hymenoscyphus ericae (Read) Korf & Kernan, was grown in liquid media containing either ammonium, the amino acid alanine, peptide (di‐, tri‐, tetra‐ or hexa‐alanine), or bovine serum albumin (BSA) as sole nitrogen (N) source. The effects of the various N sources upon production of extracellular acid proteinase, its specific activity and growth of the fungus were determined.While extracellular acid proteinase was induced in the presence of each N source, enzyme production was considerably enhanced in the culture grown with BSA. Total enzyme activity in the culture solutions declined in the order BSA ≫ ammonium > peptides and alanine. Enzyme activity per mg dry weight of mycelium was greatest in the presence of BSA.Similar yields of fungal mycelium and rates of growth were observed regardless of N source.The results are discussed in relation to quantitative aspects of the N status of heathland soils.