Journal of Chemical Ecology

, Volume 34, Issue 1, pp 32–38

Relationship Between the Endophyte Embellisia spp. and the Toxic Alkaloid Swainsonine in Major Locoweed Species (Astragalus and Oxytropis)


    • USDA/ARS Poisonous Plant Research Laboratory
  • R. Creamer
    • Department Entomology, Plant Pathology and Weed ScienceNew Mexico State University
  • D. Baucom
    • Department Entomology, Plant Pathology and Weed ScienceNew Mexico State University
  • D. R. Gardner
    • USDA/ARS Poisonous Plant Research Laboratory
  • S. L. Welsh
    • Bean Natural History MuseumBrigham Young University
  • J. D. Graham
    • New Mexico State University
  • C. Hart
    • Texas A&M University Research and Extension Center
  • D. Cook
    • USDA/ARS Poisonous Plant Research Laboratory
  • B. L. Stegelmeier
    • USDA/ARS Poisonous Plant Research Laboratory

DOI: 10.1007/s10886-007-9399-6

Cite this article as:
Ralphs, M.H., Creamer, R., Baucom, D. et al. J Chem Ecol (2008) 34: 32. doi:10.1007/s10886-007-9399-6


Locoweeds (Astragalus and Oxytropis spp. that contain the toxic alkaloid swainsonine) cause widespread poisoning of livestock on western rangelands. There are 354 species of Astragalus and 22 species of Oxytropis in the US and Canada. Recently, a fungal endophyte, Embellisia spp., was isolated from Astragalus and Oxytropis spp. and shown to produce swainsonine. We conducted a survey of the major locoweeds from areas where locoweed poisoning has occurred to verify the presence of the endophyte and to relate endophyte infection with swainsonine concentrations. Species found to contain the fungal endophyte and produce substantial amounts of swainsonine were A. wootoni, A. pubentissimus, A. mollissimus, A. lentiginosus, and O. sericea. Astragalus species generally had higher concentrations of swainsonine than Oxytropis. Swainsonine was not detected in A. alpinus, A. cibarius, A. coltonii, A. filipes, or O. campestris. The endophyte could not be cultured from A. mollissimus var. thompsonii or A. amphioxys, but was detected by polymerase chain reaction, and only 30% of these samples contained trace levels of swainsonine. Further research is necessary to determine if the endophyte is able to colonize these and other species of Astragalus and Oxytropis and determine environmental influences on its growth and synthesis of swainsonine.


LocoweedAstragalus wootoniAstragalus pubentissimusAstragalus mollissimusAstragalus lentiginosusOxytropis sericeaSwainsoninePoisonous plantLivestock poisoning

Copyright information

© US Government: Agricultural Research Service 2007