P-221 - Detection and Evaluation of Resistance Genes to Dominant Wheat Viruses in Kansas and the Development of a Multiplex RT Real-Time PCR Assay

Abstract Text: A major threat to Kansas wheat production is viral diseases, particularly wheat streak mosaic (WSM). WSM is a complex of viruses including wheat streak mosaic virus (WSMV, Tritimovirus tritici), Triticum mosaic virus (TriMV, Poacevirus tritici), and high plains wheat mosaic virus, (HPWmoV, Emaravirus tritici). Effective disease management currently relies on varieties with temperature sensitive resistance genes and accurate diagnostic tools. A statewide survey was conducted in 2019-2021 and 2024-2025 to assess wheat virus prevalence in Kansas winter wheat fields. Of the 260 samples collected in 2019-2024, 169 (65%) tested positive for WSMV via enzyme-linked immunosorbent assay (ELISA). Samples from 2024 and 2025 are breeding lines with known resistance genes (Wsm1, Wsm2, Wsm3). Positive samples will be tested using Nanopore sequencing to confirm viruses present, allow comparisons of population structures across the state, and determine the influence of deployed genetic resistance on population structure. This will indicate if any mutations are occurring and, paired with weather data, will assist in monitoring durability of the few resistance genes available. In addition to evaluating genetic resistance and population structure, this research aims to develop and validate a TaqMan multiplex reverse transcriptase qPCR assay to detect several wheat viruses in a single reaction. The data generated from this research will influence the deployment of genes in breeding efforts, contribute to the design of a new diagnostic assay, and aid producers in variety selection.