RELATIONSHIP BETWEEN AFLATOXIN BIOSYNTHESIS AND SPORULATION IN ASPERGILLUS-PARASITICUS

Regulation of aflatoxin biosynthesis during differentiation of Aspergi llus parasiticus was analyzed by using a drug that inhibits the develo pment of the fungus and mutants affected in sporulation. Diaminobutano ne, a competitive inhibitor of ornithine decarboxylase, repressed spor e germination. If added after spore germination had occurred, it block ed sporulation completely and suppressed aflatoxin biosynthesis, but w as only partially inhibitory of mycelial growth. Putrescine partially counteracted the inhibitory effect of the drug on both sporulation and aflatoxin biosynthesis. Analysis of mutants affected in sporulation c onfirmed the existence of a relationship between sporulation and aflat oxin formation. A nonsporulating mutant was unable to synthesize aflat oxins. In a sectorial mutant, the sporulating sector synthesized aflat oxins normally whereas the asporogenous sector was unable to do so. It is suggested that regulation of aflatoxin biosynthesis is correlated with the sporulation process. (C) 1997 Academic Press.