Aspergillus nidulans sodVI Cl mutation causes defects in cell wall biogenesis and protein secretion

Growth at the restrictive temperature (42degreesC) of Aspergillus nidulans 13120, carrying the conditional-lethal mutation sod(VI)Cl, was partially improved by the addition of 1.0 M sorbitol to the medium. The mutant grown at 42degreesC, with osmotic stabilizer, showed abnormal hyphal morphology, a decrease in beta-1,3-glucan synthase activity as well as cell wall sugar content, but an increase in chitin synthase activity and N-acetyl-glucosamine content. The mutation also affected the secretion of extracellular protease. The temperature-dependent osmo-sensitive phenotype of a Saccharomyces cerevisiae alpha-COP mutation can be rescued by the A. nidulans sod(VI) C+ gene. These results indicate that the sod(VI)Cl mutation affects proper processing of secretory proteins destined for the surface of cells or beyond. (C) 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.