title: Fungicide treatment and clipping of Oxytropis sericea does not disrupt swainsonine concentrations.
abstract: Swainsonine, an indolizidine alkaloid, is an α-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 is produced by associated endophytic fungi. Prolonged consumption of swainsonine-containing plants by livestock causes a condition characterized by weight loss, depression, altered behavior, decreased libido, infertility, and death. In contrast, Astragalus and Oxytropis that do not contain swainsonine may present a valuable food source for grazing livestock in regions where palatable forage is scarce. This study tested the hypothesis that swainsonine concentrations may be reduced by fungicide treatment or by clipping, thus reducing plant toxicity. Additionally we hypothesized that clipping plants may provide a mechanism for horizontal transmission of the endophyte. To this end, four different fungicides were applied to render the endophyte non-viable, and plant vegetative tissues were periodically clipped. Treatment of Oxytropis sericea with any of four different fungicides did not alter swainsonine concentrations in plants at any of three harvest times. Additionally, we found that individual or multiple clippings 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 of the endophyte among individual plants due to clipping.
authors.affiliation: USDA/ARS Poisonous Plant Research Laboratory, 1150 East 1400 North, Logan, UT 84341, United States. Electronic address: daniel.cook@ars.usda.gov.
authors.forename: Daniel
authors.initials: D
authors.lastname: Cook
authors.affiliation: USDA/ARS Poisonous Plant Research Laboratory, 1150 East 1400 North, Logan, UT 84341, United States.
authors.forename: Dale R
authors.initials: DR
authors.lastname: Gardner
authors.affiliation: USDA/ARS Poisonous Plant Research Laboratory, 1150 East 1400 North, Logan, UT 84341, United States.
authors.forename: Jessie M
authors.initials: JM
authors.lastname: Roper
authors.affiliation: Utah State University, Department of Plants, Soils, and Climate, 4820 Old Main Hill, Logan, UT 84322-4820, United States.
authors.forename: Corey V
authors.initials: CV
authors.lastname: Ransom
authors.affiliation: USDA/ARS Poisonous Plant Research Laboratory, 1150 East 1400 North, Logan, UT 84341, United States.
authors.forename: James A
authors.initials: JA
authors.lastname: Pfister
authors.affiliation: USDA/ARS Poisonous Plant Research Laboratory, 1150 East 1400 North, Logan, UT 84341, United States.
authors.forename: Kip E
authors.initials: KE
authors.lastname: Panter
mesh_terms: D005659:Fungicides, Industrial / Q000494:pharmacology*; D033021:Oxytropis / Q000378:metabolism*; D017026:Swainsonine / Q000378:metabolism*
chemical_list: D005659:Fungicides, Industrial; D017026:Swainsonine
keywords: Clipping; Fungicide; Locoweed; Oxytropis; Swainsonine