On the Role of 6-Methylsalicylic Acid in the Biosynthesis of Fungal Benzoquinones.

Abstract

6-Methylsalicylic acid, biogenetically C14-labelled from acetate, has been tested as a precursor of the quinonoid pigments produced by Lentinus degener, Gliocladium roseum, Aspergillus fumigatus, and Penicillium spinulosum. The radioactive phenolic acid was not incorporated into any of the pigments (e.g. fumigatin) formed by A. fumigatus and P. spinulosum, and labelled aurantiogliocladin from G. roseum to a very small extent, only. In L. degener, however, 6-methylsalicylic acid was excellently utilized for pigment formation, and chemical degradation of radioactive 4-methoxy-6-hydroxy-2,5-tolu-guinone (the major pigment in L. degener) derived from specifically C14-labelled 6-methylsalicylic acid established that the precursor was incorporated as a unit (above the acetate level). The biogenetic role of 6-methylsalicylic acid in the formation of fungal benzoquinones is discussed.