Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/27/2014
Publication Date: 3/27/2014
Citation: Proctor, R., Stanley, A.M., Malmierca, M.G., Alexander, N.J., Brown, D.W., Gutierrez, S., Mccormick, S.P. 2014. Effects of acquisition, loss, and neofunctionalization of trichothecene biosynthetic genes on variation in trichothecene structure, pathway regulation, and self-protection mechanisms in the Hypocreales. Meeting Abstract. Interpretive Summary:
Technical Abstract: Trichothecenes are secondary metabolites produced by multiple genera in the order Hypocreales, including Fusarium, Myrothecium, Stachybotrys, and Trichoderma. These metabolites are of concern because they are toxic to humans and animals, can contribute to pathogenicity in Fusarium, and are required for full biological control activity in Trichoderma. All trichothecenes have the same core structure, a three-ring skeleton with an epoxide function, but differ in patterns of oxygenation and acylation. In this study, comparison of trichothecene biosynthetic gene (TRI) clusters in hypocrealean genera and functional analysis of individual genes provide evidence that variation in trichothecene structure among genera can result from acquisition, loss, and neofunctionalization of TRI genes. Gene loss and acquisition have also contributed to fundamental changes in TRI gene regulation, as is evident by a transcription factor gene that is unique to the TRI cluster in one Fusarium lineage, and by the presence of the regulatory genes TRI6 and TRI10 in all genera examined except Beauveria. Analysis of phylogenetic relationships of TRI genes and of trichothecene-producing genera provide evidence for the order in which such changes in the TRI cluster have occurred. Together, the results provide insight into the evolutionary history of biochemical and regulatory pathways as well as self-protection mechanisms responsible for trichothecene production in the Hypocreales.