Poster

Nicholas Rhoades^1,2, William Hay¹ , Nathan Kemp¹, Susan McCormick¹, Jonathan Henson^1,2, Kirk Broders¹, Guixia Hao¹
1. USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, Mycotoxin Prevention and Applied Microbiology Research Unit., Peoria, IL. 61604, USA.
2. Oak Ridge Institute for Science and Education, USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, Mycotoxin Prevention and Applied Microbiology Research Unit, Peoria, IL 61604, USA
Corresponding Author: Nicholas Rhoades, nicholas.rhoades@usda.gov

Rhodes, Nicholas

Nicholas.Rhoades@usda.gov

Fusarium graminearum is the primary causal agent of Fusarium Head Blight (FHB), a devastating fungal disease on wheat and barley that is responsible for over $1 billion in economic losses annually. During infection, F. graminearum produces and deposits harmful trichothecene mycotoxins, including vomitoxin (DON) on FHB infected-heads, contaminating grain products and making them unsafe for use in food or feed. DON also acts as a virulence factor in wheat, promoting FHB spread within an infected head through the rachis; therefore, disease control strategies that inhibit DON synthesis are also effective at inhibiting FHB spread. Trichoderma harzianum, the most common Trichoderma spp. in commercial BCA formulations, has shown moderate biocontrol of FHB when applied on wheat heads and produces a butenolide secondary metabolite called harzianolide, which has been shown to be an effective elicitor of plant defense in tomato and canola studies. Here we present preliminary data showing T. harzianum, and harzianolide itself, can inhibit trichothecene production in culture. Through bioinformatic and biochemical experiments, we have putatively identified the harzianolide biosynthetic gene cluster and screened 40+ species of Trichoderma for this cluster. Methods to optimize harzianolide production in fermentation cultures resulted in an 8x increase in harzianolide yield, providing sufficient product for use in future experiments.

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