Spore germination and carbon metabolism in Fusarium solani: VI. Ethanol metabolism and the biosynthesis of amino acids

Abstract

Although macrospore germination in Fusarium solani requires ethanol under specified cultural conditions, it is not likely that this has any general significance in nature; the requirement is strain-specific and can be modified by the growth medium on which spores are produced. Under the conditions in which ethanol is required it is fully replaced by serine, but it is partially and only at relatively high concentrations replaced by threonine, arginine, and glutamine. Inhibitor and incorporation experiments show that ethanol is converted to serine by a metabolic route that requires the action of ethanol dehydrogenase but does not involve glycine, acetate, or the tricar☐ylic acid cycle. Overall ethanol metabolism, however, does involve acetate or acetyl-coenzyme A, as evidenced by a partial inhibition of it by fluoroacetate. Spores metabolizing labeled acetate, which does not replace ethanol in spore germination, incorporate label into several amino acids but not into serine, while serine is the first and most prominent amino acid product of ethanol metabolism.