Submitted to: Mycopathologia
Publication Type: Review Article
Publication Acceptance Date: February 1, 2006
Publication Date: April 15, 2006
Citation: Cary, J.W., Ehrlich, K. 2006. Aflatoxigenicity in Aspergillus: molecular genetics, phylogenetic relationships and evolutionary implications. Mycopathologia. 162:167-177. Technical Abstract: Aflatoxins are toxic and carcinogenic secondary metabolites produced by isolates of Aspergillus section Flavi, as well as a number of Aspergillus isolates that are classified outside of section Flavi. Characterization of the aflatoxin and sterigmatocystin gene clusters and analysis of factors governing regulation of their biosynthesis has resulted in these two mycotoxins being the most extensively studied of fungal secondary metabolites. This wealth of information has allowed the determination of the molecular basis for non-production of aflatoxin in natural isolates of A. flavus and domesticated strains of A. oryzae. This review provides an overview of the molecular analysis of the aflatoxin and sterigmatocystin gene clusters, as well as new information on an aflatoxin gene cluster identified in the non-section Flavi isolate, Aspergillus ochraceoroseus. Additionally, molecular phylogenetic analysis using aflatoxin biosynthetic gene sequences, as well as ribosomal DNA internal transcribed spacer sequences between various section Flavi and non-section Flavi species, has enabled determination of the probable evolutionary history of the aflatoxin and sterigmatocystin gene clusters. A model for the evolution of the aflatoxin and sterigmatocystin gene clusters, as well as possible biological roles for aflatoxin, are discussed.