The role of endophyte in determining swainsonine concentrations

Authors: Cook, Daniel; Gardner, Dale; Grum, Daniel; Pfister, James

Submitted to: International Symposium on Poisonous Plants
Publication Type: Proceedings
Publication Acceptance Date: 5/30/2015
Publication Date: 6/5/2015
Citation: Cook, D., Gardner, D.R., Grum, D.S., Pfister, J.A. 2015. The role of endophyte in determining swainsonine concentrations. International Symposium on Poisonous Plants. 9:89-94.

Interpretive Summary: Differences in swainsonine concentrations between two Oxytropis sericea populations were due to differences in swainsonine production between the endophyte isolates from each population with no apparent influence of the plant genotype. The results from a common garden experiment of O. sericea plants from each population, a common environment experiment using Undifilum oxytropis isolates from each population, and a plant genotype by endophyte cross inoculation experiment, clearly show this finding.

Technical Abstract: Locoweeds contain the toxic indolizidine alkaloid swainsonine, which is produced by the endophytic fungi Undifilum species. Previously we reported that swainsonine concentrations differ between populations of Oxytropis sericea. We hypothesized that the genotype of the plant, endophyte, or an interaction of the two may be responsible for the differences in swainsonine concentration between populations of O. sericea. To test this hypothesis, plants derived from seeds collected at each location were grown in a common garden, Undifilum oxytropis isolates from each location were cultured and grown in a common environment, and a plant genotype by endophyte cross inoculation was performed. Here we show that the genotype of the endophyte is responsible for the differences in swainsonine concentrations observed in the two populations of O. sericea.