|Villani, Alessandra - National Research Council - Italy|
|Moretti, Antonio - National Research Council - Italy|
|Susca, Antonia - National Research Council - Italy|
|Gutierrez, Santiago - University Of Leon|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/11/2018
Publication Date: 4/11/2018
Citation: Proctor, R., Kim, H., Villani, A., Hao, G., Bakker, M.G., Brown, D.W., Vaughan, M.M., Busman, M., O'Donnell, K., Moretti, A., Susca, A., Ward, T.J., Gutierrez, S., McCormick, S.P. 2018. Distribution and evolution of genes responsible for biosynthesis of mycotoxins in Fusarium. Meeting Abstract [abstract].
Technical Abstract: Fusarium secondary metabolites (SMs) include some of the mycotoxins of greatest concern to food and feed safety. In fungi, genes directly involved in synthesis of the same SM are typically located adjacent to one another in gene clusters. To better understand the distribution and evolution of mycotoxin biosynthetic gene clusters in Fusarium, we examined genome sequences of ~250 Fusarium species and 24 other fungi. By mapping the presence and absence of mycotoxin clusters on a phylogeny inferred from housekeeping gene sequences mined from the genome sequences, we discovered that some mycotoxin clusters are present in fusaria in which they were not expected to occur, and some clusters are absent in species previously reported to produce the corresponding mycotoxins. Our analyses have also provided evidence that horizontal gene transfer (HGT) has contributed to the current distribution of some mycotoxin clusters. However, there is also evidence that phylogenetic signals for some HGT events have been lost over time, because SM biosynthetic genes tend to diverge more quickly than housekeeping genes. Comparison of genome sequences from multiple fungal genera has provided evidence for how Fusarium mycotoxin clusters have diverged from homologous clusters in other fungi. For example, the Fusarium trichothecene biosynthetic gene (TRI) cluster has likely acquired six and lost up to six genes since it diverged from homologs in other genera. In addition, the functions of at least four Fusarium TRI genes have changed substantially since they diverged from homologs in other fungi and/or as Fusarium homologs have diverged from one another. These findings help explain the structural differences of Fusarium mycotoxins and provide tools to better assess the causes of and measures to prevent mycotoxin contamination of crops.