Authors: Isha Mittal 1, Syeda Alam 1, Elena Shulaev 1, Katherine Berg 2, Yanhong Dong 3, Harold N. Trick 4, Michael Kolomiets 2, Steve Scofield 5, and Jyoti Shah 1
1. University of North Texas, Department of Biological Sciences and BioDiscovery Institute, Denton, Texas
2. Texas A&M University, Department of Plant Pathology and Microbiology, College Station, Texas
3. University of Minnesota, Department of Plant Pathology, St. Paul, Minnesota
4. Kansas State University, Department of Plant Pathology, Manhattan, Kansas
5. USDA-Agricultural Research Service, West Lafayette, Indiana
Corresponding author: Jyoti Shah, Jyoti.Shah@unt.edu
Presenting Author: Isha Mittal
Abstract
In recent years, Fusarium head blight (FHB) has become a widespread disease that significantly impacts wheat yield and quality. Gaining insights into the molecular basis of wheat resistance to FHB is essential for developing effective disease management strategies. Our study has identified a susceptibility gene, Lpx3, associated with the 9-lipoxygenase (9-LOX) pathway, which plays a role in oxylipin biosynthesis and may influence fungal growth and cross-kingdom interactions. During Fg infection, wheat cells undergo dynamic shifts in gene expression, creating complex host-pathogen interactions. To explore the mechanisms of resistance conferred by Lpx3 knockdown, we characterized the impact of lipoxygenase derived products on fungal growth and virulence along with discovering the transcriptional networks underlying the impact of Lpx3 on fungal invasiveness. Differential expression analysis uncovered specific defense responses in FHB-resistant Lpx3-knockdown line, including upregulation of genes involved in polyketide biosynthetic processes. Additionally, F. graminearum showed varied expression of mycotoxin biosynthesis pathways during infection, allowing us to identify potential pathogenicity factors. Pharmacological experiments showed that the direct application of one of the oxylipin, 9-HOT restored the susceptibility in Lpx3-knockdown lines, as well as enhanced the expression of mycotoxin biosynthesis genes when added to liquid culture of fungus, but it did not have a direct impact on fungal growth on potato dextrose agar plates. Taken together, these results serve as a foundation for further study on the regulatory mechanism of wheat-Fg interactions as well as enhanced resistance resulting from Lpx3 knockdown.
Acknowledgement: This material is based upon work supported by the U.S. Department of Agriculture, under Agreement No. 59-0206-7-006, 59-0206-0-186, 59-0206-0-179, 59-0206-0-151, and 59-206-2-161 as cooperative projects with the U.S. Wheat & Barley Scab Initiative, Agreement No. 58-5020-1-013 as a USDA-ARS Non-Assistance Cooperative Agreement, 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.