TOXIC LOCOWEED SPECIES IN MONGOLIA AND WESTERN USA
Poisonous Plant Research
2011 Annual Report
1a.Objectives (from AD-416)
Survey grasslands of Mongolia and the western United States for species of Oxytropis, Astragalus and Swainsonia to determine which species and populations contain the toxic alkaloid swainsonine that causes locoweed poisoning in livestock.
1b.Approach (from AD-416)
The USDA/ARS Poisonous Plant Lab (PPRL) has developed chemical assays for the toxic alkaloid swainsonine and for detecting and quantifying the endophytic fungus Undifilum which produces swainsonine. Species of Oxytropis, Astragalus and Swainsona will be collected throughout Mongolia and the western United States and small samples of leaf and flower material will be sent to PPRL to determine the presence of the endophyte and concentration of swainsonine. From these samples toxicity of the species will be determined.
Identification of endophytes in Astragalus and Oxytropis species of Inner Mongolia. Locoweeds, including certain species of Oxytropis and Astragalus that contain swainsonine, are important poisonous plants throughout the world and especially in the vast native grasslands of China. Livestock sustainability and health on these important ranges are seriously threatened because of desertification and locoweed invasion. Enormous economic losses occur every year threatening the local advancement of animal husbandry and endangering the sustainability of the livestock producers in these regions. Thus far, ten strains of endophyte have been isolated from Oytropis glabra in Inner Mongolia and 42 strains of endophyte have been preliminarily isolated from Astragalus variabilis A. strictus, O. glabra, O. kansuensis, O. ochrocephala, O. glacialis, and O. sericopetala. Of these, 11 strains produce swainsonine. These endophyte strains have been classified as Undifilum oxytropis and previously described as Embellisia oxytropis according to the morphological characteristic and 5.8SrDNA/ITS sequence analysis. PCR-RFLP analysis of intergenic spacer (IGS) region for those 11 endophyte strains showed that the interspecific or intraspecific variations were present among the endophytes from different locoweed species.
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