Assistant Professor of Plant Pathology University of Minnesota Saint Paul, Minnesota, United States
Abstract Text: Sclerotinia sclerotiorum diseases cause significant yield losses across the Northern United States. Management challenges include the pathogen's broad host range, soil persistence, and incomplete crop resistance. Our work aims to provide tools for resistance screening assays and potential targets to reduce the aggressiveness of S. sclerotiorumusing biotechnology approaches. We characterized diverse S. sclerotiorum isolates for aggressiveness across crops and developed a seven-isolate subpanel with conserved cross-species virulence. Petiole inoculations with the subpanel successfully differentiated resistant and susceptible sunflower (HA441 and HA89, p <0.001) and dry bean (USPT-WM12 and Othello, p< 0.001) lines across two experimental replicates in the greenhouse. Soybean (52-82B and Dwight) and canola (Flint and Westar) lines were assayed in one experimental replicate. Transcriptomics will be used to identify conservative virulence determinants and differential gene expression between two highly aggressive isolates (Xtra7 and MNSS6) and two weakly aggressive isolates (WISS47 and JS659). Isolates that vary in interactions with crop species, SSPotter and BN172, will also be evaluated for host-specific virulence determinants. Soybean and sunflower tissues were collected 24 to 96 hours post inoculation with S. sclerotiorumfor RNA sequencing. The genes upregulated by aggressive isolates during S. sclerotioruminfection may be useful targets for RNAi-based management strategies across crop species.
