Synthesis and secretion of phosphatases by endophytic isolates of Colletotrichum musae grown under conditions of nutritional starvation

• Published in: Journal of general and applied microbiology Vol. 44; no. 6; pp. 381 - 387
• Main Authors: Maccheroni, Walter, Jr, Azevedo, João Lúcio
• Format: Journal Article
• Language: English
• Published: Tokyo Applied Microbiology, Molecular and Cellular Biosciences Research Foundation 1998; Microbiology Research Foundation; Japan Science and Technology Agency
• Subjects: Biological and medical sciences; Colletotrichum musae; endophyte; Fundamental and applied biological sciences. Psychology; fungi; Glomerella; Growth, nutrition, metabolism, transports, enzymes. Molecular biology; Microbiology; Mycology; nutritional starvation; phosphatase; phosphodiesterase; protein secretion; Alkaline phosphatase; Enzyme; Phosphoric monoester hydrolases; Environmental factor; Esterases; Biosynthesis; Nutrient starvation; Fungi; Colletotrichum musae; Enzymatic activity; Microorganism culture; Hydrolases; Endophyte; Isolate; Nutrient; Fungi Imperfecti; Acid phosphatase; Thallophyta
• ISSN: 0022-1260; 1349-8037
• DOI: 10.2323/jgam.44.381

Even though fungal phosphatases are widely used to study ambient-regulated gene expression, little is known about these enzymes in the agriculturally important genus Colletotrichum. We have therefore identified several phosphatase activities in endophytic isolates of Colletotrichum musae grown under conditions of nutritional sufficiency or starvation for sources of phosphorus (P), nitrogen (N), carbon (C), and sulphur (S). These enzyme forms could be distinguished by substrate specificity, optimum pH, activation and inhibition by some substances, response to nutritional starvation, and pattern of migration in native gel electrophoresis. At least four individual phosphatase activities were identified under the growth conditions employed. A pH 5.0 acid phosphatase and an Mg2+-dependent pH 7.5 phosphodiesterase were expressed under all growth conditions at constant rates. Under conditions of P-starvation, derepression of a major pH 6.0-acid phosphatase was observed in cell-free extracts and the culture medium. A synthesis of alkaline phosphatase activities followed a more distinct pattern. Under conditions of nutritional sufficiency of P- or N-starvation, only a single intracellular enzyme form (optimum pH 10) was observed, which was resolved as a single electrophoretic activity band. However, in media lacking C or S sources additional alkaline phosphatase forms were derepressed with a concomitant increase in the overall enzyme activity level measured at pH 10. To our knowledge, this report represents the most detailed study of phosphatases in Colletotrichum and the first partial characterization of the phosphatase system in an endophytic fungus.