Role of the gene tri14 in biosynthesis of the trichothecene toxin harzianum A in Trichoderma arundinaceum

Authors: MARTINEZ-REYES, NATALIA - University Of Leon; CARDOZA, ROSA - University Of Leon; McCormick, Susan; Hao, Guixia; RODRIGUEZ-FERNANDEZ, J - University Of Leon; Proctor, Robert; GUTIERREZ, SANTIAGO - University Of Leon

Submitted to: Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2025
Publication Date: 8/26/2025
Citation: Martinez-Reyes, N., Cardoza, R.E., McCormick, S.P., Hao, G., Rodriguez-Fernandez, J., Proctor, R.H., Gutierrez, S. 2025. Role of the gene tri14 in biosynthesis of the trichothecene toxin harzianum A in Trichoderma arundinaceum. Toxins. https://doi.org/10.3390/toxins17090427.
DOI: https://doi.org/10.3390/toxins17090427

Interpretive Summary: Trichothecenes are among the fungal toxins of most concern to food feed safety because of their toxicity and frequent occurrence in crops used to produce human food and animal feed. Because of the threat trichothecenes pose to the health of humans, livestock and pets, there are significant research efforts worldwide to develop control practices that block accumulation of trichothecene in crops. Fungal genes that are involved in trichothecene production are potential targets for such control practices. The gene tri14 is not essential for trichothecene production but speeds up a biochemical reaction that occurs during trichothecene formation. To determine whether tri14 is an effective target to block trichothecene contamination of crops, ARS Scientists in Peoria, Illinois, and their collaborators at the University of Leon in Spain carried out experiments to determine how tri14 impacts the trichothecene-producing fungus Trichoderma arundinaceum. The research demonstrated that inactivation of tri14 severely reduces the ability of T. arundinaceum to produce trichothecenes and impairs other biological processes in the fungus. Thus, the research demonstrates that, even though it is not essential for trichothecene production, tri14 can be an effective mechanism to block trichothecene contamination.

Technical Abstract: Trichothecenes are a family of toxic metabolites produced by multiple fungal species. All trichothecene analogs include an epoxide-containing tricyclic structure known as 12,13-epoxytrichothec-9-ene (EPT) but differ by the presence, absence and types of substituents attached to EPT. Among the 21 known genes associated with trichothecene biosynthesis, tri14 is one of only three that are universally found in all trichothecene-producing fungi. Recent studies have revealed that the tri14-encoded protein, Tri14, enhances the biosynthetic reaction that forms EPT, a reaction previously thought to occur spontaneously. In our study, we assessed the impact of tri14 deletion on the biology of Trichoderma arundinaceum, a producer of the trichothecene harzianum A (HA). The results revealed that tri14 deletion reduced HA production by 69%, an outcome that was associated with diminished antifungal activity. To our knowledge, this is the first study showing that tri14 is required for wild-type production of a trichothecene analog by a fungal organism. tri14 deletion also had moderate effects on the expression of some other trichothecene biosynthetic genes, as well as in the production of metabolites beyond HA. These results suggest that Tri14 plays a crucial role in EPT formation, leading to diverse downstream effects on the biology of T. arundinaceum.