Light-stimulated toxin production in Helminthosporium maydis, race T, cultures

Abstract

Cultures of Helminthosporium maydis, race T, grown on modified Fries' medium under 1300 ft-c of continuous light produced at least 7 times more toxin than those grown in the dark. Thin-layer chromatography of the chloroform extracts of culture filtrates revealed that light has a general effect on metabolism of the fungus rather than a specific effect on toxin production. Light-grown cultures were found to be richer in chloroform-extractable metabolites including the toxin. The defined medium suggested by Karr et al. (5) was found to be unsuitable for high yields of toxin production.