Fusarium head blight (FHB) caused by Fusarium graminearum is an economically important and serious disease of wheat and other small grain cereals that leads to reduced grain yield and mycotoxin contamination. 9-lipoxygenases catalyze the first step in the synthesis of oxylipins (oxidized lipids) that have multitude of roles in plants, including signaling associated with stress response. Oxylipins have also been reported to be involved in fungal development and inter-kingdom communication. In wheat, RNA-interference (RNAi)-mediated knockdown of the Lpx3 locus resulted in enhanced resistance against F. graminearum in greenhouse studies. To identify non-GMO knockdown alleles of Lpx3 that could provide new resistance-conferring genotypes with the potential for their integration into breeding programs, we have identified wheat TILLING lines with Lpx3 variants containing mutations that are predicted to knockdown gene function. FHB disease severity and DON accumulation was significantly reduced in these Lpx3 variants. Efforts are underway to develop lines with mutations at multiple Lpx3 homeologs to evaluate the effect of the variant alleles on plant growth, development and grain yield, in addition to FHB. In parallel, physiological experiments are underway to identify the impact of Lpx3 knockdown on oxylipin profile, and dual RNA-seq is being conducted to identify temporal changes in wheat and fungal gene expression that are influenced by the genotype at the Lpx3 locus.

Acknowledgement

This material is based upon work supported by the U.S. Department of Agriculture, under Agreement No. 59-0206-0-179, 59-0206-0-186, and 58-5020-1-013 as cooperative projects with the U.S. Wheat & Barley Scab Initiative, and by Award No.2021-67013-33573 from the U.S. Department of Agriculture’s National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.