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ARS Home » Pacific West Area » Logan, Utah » Poisonous Plant Research » Research » Publications at this Location » Publication #244962
Title: Swainsonine Concentrations and Endophyte Amounts of Undifilum oxytropis in Different Plant Parts of Oxytropis sericea

Author
item Cook, Daniel
item Gardner, Dale
item Ralphs, Michael
item Pfister, James
item Welch, Kevin
item Green, Benedict - Ben

Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/21/2009
Publication Date: 11/11/2009
Citation: Cook, D., Gardner, D.R., Ralphs, M.H., Pfister, J.A., Welch, K.D., Green, B.T. 2009. Swainsonine Concentrations and Endophyte Amounts of Undifilum oxytropis in Different Plant Parts of Oxytropis sericea. Journal of Chemical Ecology, Vol. 35(10):1272-1278. (www.springerlink.com) DOI 0.1007/s10886-009-9710-9

Interpretive Summary: A fungal endophyte (Undifilum oxytropis) is responsible for the synthesis of swainsonine in Oxytropis and Astragalus species, commonly known as locoweeds. The distributioin of swainsonine concentrations and endophyte amounts in different plant parts of O. sericea were investigated. In addition, two groups of O. sericea plants were identified: one that accumulated high concentrations of swainsonine and another where swainsonine was not detected or concentrations that were near the detection threshold. The plants with high swainsonine concentrations had quantitatively higher amounts of endophyte. Alternatively, plants where swainsonine was not detected or concentrations that were near the detection threshold had quantitatively lower endophyte amounts. Furthermore, swainsonine and endophyte amounts were shown to not be uniformly distributed from the same plant.

Technical Abstract: Locoweeds are Astragalus and Oxytropis species that contain the toxic alkaloid swainsonine. Swainsonine accumulates in all parts of the plant with the highest concentrations found in the above ground parts of the plant. A fungal endophyte, Undifilum oxytropis, found in locoweed plant species has been shown to be responsible for the synthesis of swainsonine. Using quantitative PCR the endophyte can be quantified in locoweed species. Endophyte amounts differ between plant parts and in some instances does not mirror the concentrations of swainsonine in the corresponding parts. Two biotypes of Oxytropis sericea were identified: one that accumulated high concentrations of swainsonine and another where swainsonine was not detected or concentrations that were near the detection threshold. The plants with high swainsonine concentrations had quantitatively higher amounts of endophyte. Alternatively, plants where swainsonine was not detected or concentrations that were near the detection threshold had quantitatively lower endophyte amounts. In addition, swainsonine and endophyte amounts were shown to not be uniformly distributed from the same plant when separated vertically into stalks representing leaves, scape(s), and flowers/pods. These findings provide evidence as to why plants in the same population accumulate different concentrations of swainsonine and have important implications for sampling of locoweed plants.