|Cardoza, Rosa - University Of Leon|
|Lindo, Laura - University Of Leon|
|Alexander, Nancy - Retired ARS Employee|
|Santiago, Gutierrez - University Of Leon|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/13/2018
Publication Date: 6/13/2018
Citation: Cardoza, R.E., Proctor, R., McCormick, S.P., Kim, H.-S., Stanley, A.M., Lindo, L., Kelly, A.C., Brown, D.W., Vaughan, M.M., Alexander, N.J., Busman, M., Santiago, G. 2018. New insights into the organization and regulation of trichothecene biosynthetic genes in Trichoderma [abstract].
Technical Abstract: Collectively, species of the genus Trichoderma can produce numerous structurally diverse secondary metabolites (SM). This ability is conferred by the presence of SM biosynthetic gene clusters in their genomes. Species of Trichoderma in the Brevicompactum clade are able to produce trichothecenes, a family of toxic sesquiterpenoid metabolites. Trichothecenes are also produced by several plant-pathogenic fungi, and at least one entomopathogenic fungus, Isaria tenuipes. Trichothecenes are harmful to the health of humans and domestic animals, and some can accumulate in crops where they pose health risks. In fact, some trichothecenes produced by species of Fusarium are among the mycotoxins of greatest concern to food and feed safety. Trichothecenes are produced by diverse fungal genera, including the Sordariomycetes genera Fusarium, Myrothecium, Spicellum, Stachybotrys, Trichoderma, and Trichothecium, and the Dothideomycetes genera Microcyclospora and Peltaster. The predominant trichothecenes produced by Trichoderma species are harzianum A (HA) and trichodermin. These two compounds exhibit markedly different biological activities. Thus, while trichodermin is highly phytotoxic, HA lacks this activity on in vivo assays. In Trichoderma arundinaceum, trichothecene biosynthetic (tri) genes are located at three loci: one locus has seven tri genes (tri3, tri4, tri6, tri10, tri12, tri14, and tri22); a second locus has two tri genes (tri17 and tri18); and a third locus has one gene (tri5). In this study, we used deletion and complementation analyses to characterize the function of the T. arundinaceum ortholog of tri6, which encodes a Cys2His2 Zn-finger protein. The results of these analyses indicated that tri6 is required for high (wild-type) levels of expression of all tri genes as well as some genes required for synthesis of mevalonate, which is a precursor of trichothecene biosynthetic pathway. In addition, tri6 deletion affected expression of 35% of the 10,539 predicted genes in the T. arundinaceum genome, a phenomenon that has also been reported in F. graminearum.