Submitted to: Inoculum
Publication Type: Abstract Only
Publication Acceptance Date: May 21, 2002
Publication Date: June 30, 2002
Citation: Klich, M.A., Cary, J.W., Beltz, S.B., Bennett, C.A. 2002. A molecular comparison of aflatoxin/sterigmatocystin biosynthetic pathways of four Aspergillus species. Inoculum. 53(3):39. Technical Abstract: The genes for biosynthesis of the mycotoxins aflatoxin (AF) and sterigmatocystin (ST) are similar in that they are clustered and are similar in structure and function. However, for the well-studied species A. parasiticus and A. nidulans, which produce AF and ST respectively, the arrangement of the genes in the cluster is different and the amino acid sequence of the individual genes can be quite different. Two species not closely related morphologically to A. parasiticus produce aflatoxin, A. ochraceoroseus and A. venezuelense. The order of the genes in the A. ochraceoroseus cluster is more similar to that of A. nidulans and A. parasiticus. Within genes, the % amino acid sequence similarity of A. ochraceoroseus to A. parasiticus or A. nidulans was roughly equivalent to that of A. parasiticus to A. nidulans, except for the regulatory gene aflR, for which the A. ochraceoroseus to A. nidulans similarity level was twice that of A. parasiticus to A. nidulans. DNA of A. venezuelense probed with genes of the other three species did not hybridize at all to some of the genes, but when hybridization occurred, it was stronger with genes from A. ochraceoroseus and A. nidulans than those from A. parasiticus. These data indicate that the aflatoxin biosynthetic pathways for A. ochraceoroseus and A. venezuelense are more closely related to that of the sterigmatocystin-producer A. nidulans than to the aflatoxin-producer A. parasiticus.