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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Mycotoxin Prevention and Applied Microbiology Research » Research » Publications at this Location » Publication #324468
Title: Dynamic regions within and horizontal transfer of an otherwise stable gene cluster responsible for synthesis of the Fusarium mycotoxin fusaric acid

Author
item Proctor, Robert
item Brown, Daren
item Busman, Mark
item RYU, JAE-GEE - Rural Development Administration - Korea

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/6/2016
Publication Date: 4/6/2016
Citation: Proctor, R., Brown, D.W., Busman, M., Ryu, J. 2016. Dynamic regions within and horizontal transfer of an otherwise stable gene cluster responsible for synthesis of the Fusarium mycotoxin fusaric acid [abstract].

Interpretive Summary:

Technical Abstract: The Fusarium mycotoxin fusaric acid is toxic to plants as well as animals, but its function in the biology of the fungus is not known. Here, we used genome sequencing to survey multiple species in 18 lineages (species complexes) of Fusarium for the presence of the fusaric acid biosynthetic gene (FUB) cluster. We detected the cluster in all members of the closely related F. babinda, F. fujikuroi, F. nisikadoi, F. oxysporum and F. redolens species complexes, and in the distantly related species F. aywerte, but not in other fusaria. Phylogenetic analyses of FUB genes suggest that the presence of the cluster in F. aywerte resulted from horizontal transfer from an unidentified, close relative of the F. fujikuroi species complex (FFSC). Two regions within the FUB cluster include insertions of one or more genes that are not considered FUB genes because their presence is variable, they are not co-regulated with FUB genes, and they are absent in some species that produce fusaric acid. Analysis of gene and pseudogene content of these regions indicates that they are highly dynamic with respect to gene acquisition and loss. The largest of the insertions consisted of 21 genes that were likely translocated from another region of the genome. Phylogenetic analysis indicates that the translocation occurred early in the divergence of one FFSC lineage, i.e., the American clade. A second, four-gene insertion occurred later in the divergence of another FFSC lineage (the African clade) and is associated with rearrangement within the FUB cluster. Comparisons of multiple biosynthetic gene clusters in Fusarium and other fungi indicate that regions within clusters that are susceptible to multi-gene insertions are uncommon. The presence of the FUB cluster in all members of five species complexes suggests strong selection to maintain fusaric acid production in certain lineages of Fusarium, which in turn suggests that the mycotoxin has an important biological function in these lineages.