|SABALLOS, ANNA - Oak Ridge National Laboratory|
|SOLER-GARZON, ALVARO - Washington State University|
|HART, JOHN - Earthwork Seeds Inc|
|LIPKA, ALEX - University Of Illinois|
|Miklas, Phillip - Phil|
|PEACHEY, RONALD - Oregon State University|
|TRANEL, PAT - University Of Illinois|
Submitted to: Frontiers in Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/2/2022
Publication Date: 6/1/2022
Citation: Saballos, A., Soler-Garzon, A., Brooks, M.D., Hart, J., Lipka, A., Miklas, P.N., Peachey, R.E., Tranel, P., Williams, M. 2022. Multiple genomic regions govern tolerance to sulfentrazone in snap bean (Phaseolus vulgaris L.). Frontiers in Agronomy. 4. Article 869770. https://doi.org/10.3389/fagro.2022.869770.
Interpretive Summary: Registering an herbicide on a minor crop requires a thorough understanding of risk of crop injury from the herbicide. Weeds, especially waterhemp, are becoming more difficult to control in snap bean. While sulfentrazone is relatively effective at controlling numerous broadleaf weeds, including waterhemp, snap bean tolerance to the herbicide is unknown. We investigated snap bean tolerance to sulfentrazone in a diversity panel with 277 snap bean entries. In general, snap bean is sensitive to sulfentrazone when applied at a use rate that is most effective at controlling waterhemp; however, some snap bean entries are highly tolerant to the herbicide. We identified several genomic regions associated with crop tolerance to sulfentrazone. The impact of this work is identifying candidate genes conditioning plant tolerance to sulfentrazone which may be exploited for crop improvement and understanding weed resistance.
Technical Abstract: The availability of effective weed management tools against waterhemp (Amaranthus tuberculatus) is crucial to maintain profitable production in snap bean (Phaseolus vulgaris L.). Preemergence herbicides enable the crop to gain a size advantage over the weed, but the few preemergence herbicides registered in snap bean have poor control of waterhemp. Sulfentrazone, a protoporphyrinogen oxidase (PPO) -inhibiting herbicide, provides significant control of waterhemp and other problematic weeds. However, crop tolerance to the herbicide is poorly known. To quantify snap bean tolerance to sulfentrazone and investigate the underlying tolerance mechanism, a genome-wide association mapping study was conducted using field-collected data on a snap bean diversity panel. Response to preemergence application of sulfentrazone was measured using plant population density and shoot biomass variables. High levels of crop tolerance were found in several entries including Bush Romano 71, Navarro, and Flamata. Snap bean tolerance to sulfentrazone is associated with multiple genomic regions, indicating the trait is likely a non-target site resistance (NTSR). Rapid metabolism of the herbicide, as well as differential tolerance to peroxidative stress have been postulated as the mechanisms of NTSR to PPO-inhibiting herbicides. In this study, several cytochrome P450 and ABC transporter genes were localized in associated genomic regions. Of particular interest are the genes Phvul.004G023066 and Phvul.004G023132, annotated as MDR exporters. Homologs of those genes have been directly implicated in soybean tolerance to several herbicides including PPO-inhibitors. Alleles conditioning snap bean tolerance to sulfentrazone identified in the diversity panel shed light on herbicide metabolism and could be used in snap bean improvement. Further research is necessary to confirm candidate genes and their functions.