Project Number: 2092-21220-002-13-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2017
End Date: Aug 31, 2020
Evaluate C. quinoa and other trap crops to reduce Potato Cyst Nematode (PCN) multiplication rate. Evaluate potential toxicity of S. sisymbriifolium against PCN. Partially purify putative toxins from S. sisymbriifolium. Evaluate the potency of a partially purified potato extract on hatching.
Host and hatching assays for C. quinoa will be conducted in cooperator's laboratory using standard protocols. Seeds will be obtained from Clark Seed Inc., Idaho Falls, or from Washington State University. The cultivars of C. quinoa showing promise as trap crops will be tested against PCN in field micro-plots in Shelley, Idaho. To determine potential toxicity of S. sisymbriifolium against PCN, 6-week old S. sisymbriifolium roots will be harvested, frozen, and freeze dried. The dried material will be ground to a fine powder and stored at 4°C. Root material will be extracted with hydrophilic and hydrophobic solvents. Each of the solvent-extracted fractions will be used in nematode bioassays to determine PCN toxicity. Those fractions demonstrating toxicity will be analyzed using liquid chromatography coupled with mass spectrometry. Identified compounds will either be isolated or if available, purchased from a commercial source, and used in PCN bioassays. This will be accomplished by first exposing eggs to the extract or one of its biologically active components, followed by hatching assays with potato root diffusate or soil extract PCN encysted eggs will be exposed to different concentrations of the lyophilized extracts. After one week exposure, viability of encysted eggs will be determined by staining with Meldola’s blue. Hatching assays of encysted eggs will be conducted with potato root diffusate or with soil extract. Bioassays of encysted PCN eggs exposed to the different lyophilized extracts will be done using standard protocols used in cooperator's laboratory. Our goal is to identify one or more compounds from litchi tomato roots that exhibit PCN toxicity. To gain additional information about how to use hatching factors to control PCN, three partially purified total hatching factor extracts will be prepared from potato roots, tubers and leafs using methods already developed in the ARS lab. These will then tested in replicated dilution hatching assays in the cooperator's lab to establish efficacy in promoting egg hatch. These extracts are expected to contain the total hatching factors present in potatoes, and this information will help establish a baseline for the total activity present in a plant and provide a baseline against which increasingly purified fractions can be compared.