Mechanism of Ethylene and Carbon Monoxide Production by Septoria musiva

Abstract

S. musiva, a causative agent of premature defoliation of cottonwood trees, has been shown previously to produce ethylene and carbon monoxide (CO) on media containing glucose, methionine, and iron. Chemical analyses have shown that all three substances are present in the cottonwood leaves. Of seven carbohydrates tested, none supported the production of ethylene and only glucose supported CO production. From 24 amino acids employed as sole carbon sources only methionine and cysteine supported the production of ethylene and CO but four other amino acids supported ethylene production. Metabolic studies have demonstrated that the fungus transaminates methionine to 4-methylmercapto-2-oxobutyric acid, which presumably is acted upon by a peroxide in the presence of iron to form ethylene, formic acid, and dimethyldisulfide. Although the organism grew in a medium containing S-adenosylmethionine, glucose, and iron, no ethylene, or CO was produced. Using cell-free preparations, dihydroxyacetone was implicated as a precursor of CO.

Citation

Brown-Skrobot, Susan K.; Brown, Lewis R.; Filer, Ted H., Jr. 1985. Mechanism of Ethylene and Carbon Monoxide Production by Septoria musiva. Developments in Industrial Microbiology 26(45):566-572.