Genetic and metabolic control of trehalose and glycogen synthesis. New relationships between energy reserves, catabolite repression and maltose utilization
Panek, A.D.; Sampaio, A.L.; Braz, G.C.; Baker, S.J.; Mattoon, J.R.
Cellular and Molecular Biology Including Cyto-Enzymology 25(5): 345-354
1979
ISSN/ISBN: 0145-5680 PMID: 394841 Document Number: 150763
Different strains of Saccharomyces exhibit 2 alternative patterns of trehalose accumulation during logarithmic growth on glucose medium. The alternative phenotypes, active and inactive, apparently are determined by a single pair of allelic genes, TAC and tac. In 24 tetrads derived from 2 different diploids obtained by crossing active and inactive strains, active trehalose accumulation was always associated with maltose fermentation controlled by the constitutive, catabolite-repression-resistant gene MAL4c. The genes MAL4c and TAC are very closely linked or identical. The active pattern of trehalose accumulation is not invariably associated with maltose fermentation, since strains containing a MAL6 allele which controls inducible, catabolite-sensitive maltose fermentation exhibited the inactive pattern of trehalose accumulation. Although strains containing a tac gene exhibit little or no trehalose accumulation during growth, they can accumulate the disaccharide in glucose medium lacking a N source. Strains containing the mutant gene glc1 are deficient both in glycogen production and in trehalose accumulation. Introduction of the MAL4c gene into a glc 1 strain permits trehalose accumulation during growth on glucose, but does not reverse the defect in accumulation found in nonproliferating conditions. MAL4c exerts no significant effect on the glcyogen synthesis deficiency associated with glc1. A specific, unique relationship between maltose utilization and trehalose accumulation exists. When maltose is used as C source, active trehalose accumulation during growth occurs. This accumulation is not detectably diminished by the presence of the following genes which prevent trehalose accumulation in glucose medium: tac, glc1 and fdp. This effect of maltose cannot be ascribed solely to derepression because it is not mimicked by galactose or glycerol. Since maltose does not restore glycogen synthesis in glc1 strains, it appears that the mechanism of the maltose-dependent trehalose accumulation does not involve a generalized effect on an intermediate or reaction common to the biosynthesis of both types of carbohydrate reserve.