A high concentration of glucose inhibits Tuber borchii mycelium growth: a biochemical investigation

• Published in: Mycological research Vol. 107; no. 1; pp. 72 - 76
• Main Authors: SALTARELLI, Roberta, CECCAROLI, Paola, POLIDORI, Emanuela, CITTERIO, Barbara, VALLORANI, Luciana, STOCCHI, Vilberto
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.01.2003; Elsevier Ltd; Elsevier
• Subjects: 2-deoxyglucose; Agronomy. Soil science and plant productions; Ascomycota - enzymology; Ascomycota - growth & development; Biological and medical sciences; Culture Media; Deoxyglucose - metabolism; Economic plant physiology; fructose; Fundamental and applied biological sciences. Psychology; glucose; Glucose - metabolism; Growth and development; Growth, nutrition, metabolism, transports, enzymes. Molecular biology; hyphae; Hyphae - enzymology; mannitol; Mannitol Dehydrogenases - metabolism; microbial growth; Microbiology; Morphogenesis, differentiation, rhizogenesis, tuberization. Senescence; mycelium; Mycelium - enzymology; Mycelium - growth & development; Mycology; mycorrhizal fungi; Time Factors; Hexose; Biochemical analysis; Enzyme; Growth; Glucose; Fructose; Fungi; Regulation(control); Enzymatic activity; Morphology; Concentration effect; Hypha; Mannitol 2-dehydrogenase; Mannitol; Ascomycetes; Carbohydrate; Oxidoreductases; Polyol; Inhibition; Mycelium; Edible fungi; Thallophyta
• ISSN: 0953-7562; 1469-8102
• DOI: 10.1017/S0953756202007062

Tuber borchii mycelium (strain 1BO) is able to utilise glucose, fructose or mannitol in the culture medium as a carbohydrate source. Since sugars not only function as a metabolic resource and structural constituent of cells, but also act as important regulators of various processes, we investigated if high sugar concentrations could influence fungal growth and development. The studies performed in this paper revealed that fructose or mannitol used at high concentration (50 g l−1) in the culture medium do not influence the growth and the biochemical responses of fungus but the growth of T. borchii mycelium is subject to glucose repression. In experiments with a high glucose concentration (50 g l−1) and with 2-deoxyglucose, a non-metabolisable glucose analogue, the growth of T. borchii was halved with respect to the control (10 g l−1 of glucose). The morphological and biochemical analyses revealed that the hyphae were metabolically and functionally active, but the activity of mannitol dehydrogenase was reduced to one-third in the high glucose treatment. This is the first evidence of glucose repression of growth and activity in the ascomycetous ectomycorrhizal fungus T. borchii.