Location: Poisonous Plant Research2012 Annual Report
1a. Objectives (from AD-416):
The objectives of this research are to: 1) Evaluate and determine the adverse effects of locoweed on cattle production in New Mexico; 2) Evaluate and develop new tools for diagnostics; 3) Determine the role of a newly identified endophyte (Undifilum) in swainsonine production and locoweed growth and longevity; 4) Better understand the rangeland ecology where locoweeds dominate and evaluate methods of control (biological and chemical); and 5) Develop integrated management approaches to improve utilization of rangelands where locoweed grows.
1b. Approach (from AD-416):
This is a coordinated research approach between the USDA-ARS-Poisonous Plant Research Lab, Logan, UT and the Rangeland Research Group and College of Agriculture and Home Economics at New Mexico State University in Las Cruces, NM. The proposed joint research will include methods to: 1) better understand the ecology of locoweeds in this region which includes the Southern High Plains and Canadian Pecos Valleys of West Texas and eastern New Mexico; 2) understand more fully the biological characteristics of the locoweeds which includes the role of a newly discovered endophyte (Undifilum) in toxin (swainsonine) production within the plant and plant hardiness; 3) develop sound methods to understand the biology of the endophyte and employ molecular tools to determine if it can be supressed; 4) reduce the toxic effects in cattle and improve rangeland utilization through grazing strategies; 5) better evaluate locoweed's effects on early reproduction in cow calf operations; 6) identify biomarkers for improved diagnostics and prognosis of locoweed poisoning; and 7) develop a holistic management program to reduce livestock losses and improve the economic stability in this region.
3. Progress Report:
Locoweeds, Oxytropis and Astragalus species containing swainsonine, cause large economic losses to livestock producers in north eastern New Mexico and south eastern Colorado. The production of swainsonine and subsequent toxicity of locoweeds have been linked to infestation of toxic plant species by the endophyte, Undifilum. The relationship between the endophyte, Undifilum oxytropis, and locoweeds is being investigated and in all toxic Astragalus and Oxytropis species, swainsonine is only present if the endophyte is present, thus explaining why some populations are toxic while others are not. While the benefit of the endophyte to the plant is not understood, studies are ongoing between scientists at New Mexico State University and ARS at Logan, UT to determine what effect different levels of precipitation, nitrogen and atmospheric CO2 may have on endophyte infection and subsequent swainsonine production in the plants. Additionally, microscopic studies to identify, localize and characterize growth patterns of the fungus within the plant parts are being investigated. A combination of microscopic methods was effectively used to identify and localize the distribution of the fungus in plant tissues. Using topographical imaging it was revealed that the fungal hyphae reside in the leaves and pith of the petioles. Characterizing swainsonine producing endophytes in other locoweed species and other plant species causing similar toxicoses in livestock are being investigated.