Fungicide treatment and clipping of Oxytropis sericea does not disrupt swainsonine concentrations

Authors: Cook, Daniel; Gardner, Dale; Roper, Jessie; RANSOM, COREY - Utah State University; Pfister, James; Panter, Kip

Submitted to: Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2016
Publication Date: 9/16/2016
Citation: Cook, D., Gardner, D.R., Roper, J.M., Ransom, C.V., Pfister, J.A., Panter, K.E. 2016. Fungicide treatment and clipping of Oxytropis sericea does not disrupt swainsonine concentrations. Toxins. 122:26-30. https://doi.org/10.1016/j.toxicon.2016.09.012.
DOI: https://doi.org/10.1016/j.toxicon.2016.09.012

Interpretive Summary: Swainsonine is found in a number of plant species worldwide and prolonged consumption of these plants causes a disease condition characterized by weight loss, depression, altered behavior, decreased libido, infertility, and death. To test the hypothesis that fungicide application and clipping of vegetative plants may alter swainsonine concentrations thus rendering the plant less toxic, plants were treated with four different fungicides and clipped to determine if swainsonine concentrations were altered. Treatment of Oxytropis sericea with any of four different fungicides did not alter swainsonine concentrations in plants at any of three harvests. Additionally, we found that clipping had no effect on swainsonine concentrations; plants that contained swainsonine maintained concentrations, and plants low or absent in swainsonine also remained as such at each harvest.

Technical Abstract: Swainsonine, an indolizidine alkaloid, is an a-mannosidase and mannosidase II inhibitor that causes lysosomal storage disease and alters glycoprotein processing. Swainsonine is found in a number of plant species worldwide and prolonged consumption of these plants causes a disease condition characterized by weight loss, depression, altered behavior, decreased libido, infertility, and death. To test the hypothesis that fungicide application and clipping of vegetative plants may alter swainsonine concentrations thus rendering the plant less toxic, plants were treated with four different fungicides and clipped to determine if swainsonine concentrations were altered. Treatment of Oxytropis sericea with any of four different fungicides did not alter swainsonine concentrations in plants at any of three harvests. Additionally, we found that clipping had no effect on swainsonine concentrations; plants that contained swainsonine maintained concentrations, and plants low or absent in swainsonine also remained as such at each harvest. These results suggest that there is no evidence of horizontal transmission, and if a method were developed to remove the endophyte and thus eliminate swainsonine from plants, the plants would retain the same chemotype.