Poster

Tiana Roth¹, Avery Hickcox¹, Brian Rutter¹, Mengying Wang¹, Brian Steffenson², Oadi Matny², Josiah Mutuku¹
1. 2Blades University of Minnesota, St. Paul, MN, United States
2. University of Minnesota, Plant Pathology, St. Paul, MN, United States

Roth, Tiana

tmr@2blades.org

Fusarium head blight (FHB) caused by Fusarium graminearum is a major fungal disease that affects wheat heads and kernels leading to major yield loss. In addition to yield losses, Fusarium pathogens contaminate food and feed with toxic secondary metabolites known as mycotoxins, which compromise human and animal health, food safety, ethanol production, and international trade. Mycotoxins represent a persistent and costly national threat, leading to an estimated $2–$3 billion in annual losses for U.S. farmers. For several decades, scientists and breeders have sought genetic strategies to control mycotoxigenic fungi by conventional breeding and transgenic approaches. However, to date no lines with robust field resistance have reached the market. The lack of progress means new approaches are needed. At 2Blades, we are addressing this challenge using NLRseek™, a gene discovery platform comprising 985 nucleotide-binding leucine-rich repeat (NLR) immune receptors sourced from 18 diverse grass species and individually transformed into wheat. The platform has generated approximately 6,000 independent transgenic wheat lines, creating a unique resource for identifying resistance genes across multiple fungal pathogens. Proof-of-concept studies have demonstrated its utility, identifying 19 NLRs associated with resistance to wheat stem rust, 12 to leaf rust, and 25 to wheat blast. To extend this platform to FHB, we developed and optimized a field-based screening approach and conducted evaluations over four growing seasons (2023–2026). Remarkably, screening approximately 10% of the NLRseek™ wheat collection identified six NLRs that reproducibly reduced FHB severity under field conditions. These findings demonstrate the potential of NLRseek™ to uncover previously uncharacterized sources of resistance to this economically important disease. To advance these discoveries toward durable resistance, we are combining selected NLRs through genetic crosses to generate wheat lines carrying multiple resistance genes. The resulting progeny will be evaluated for enhanced resistance to FHB, providing an opportunity to investigate the potential benefits of NLR stacking. Recognizing that F. graminearum also causes economically important stalk and ear rots in maize, we have initiated the transfer of two NLRs into maize, with functional evaluations expected to begin in spring 2027. Together, these advances establish NLRseek™ as a promising platform for discovering novel sources of resistance to mycotoxigenic fungi and provide a foundation for developing broader and more durable genetic resistance in wheat and maize.

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