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United States Department of Agriculture

Agricultural Research Service

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2012 Annual Report

1a. Objectives (from AD-416):
Evaluate the efficacy of trap crops and potato root exudates to induce a suicide hatch of PCN.

1b. Approach (from AD-416):
Successful identification of the hatching factors would enable new approaches to eradicate PCN and potentially even eliminate it as a threat. We will continue our efforts to identify individual hatching factors using LCMS and hatching assays by fractionation of concentrated extracts. Hatching efficacy of fractions will be evaluated at the Univesity of Idaho. We will determine whether crude root exudate can also be used to induce a suicide hatch and production systems capable of producing large quantities of highly active hatching factors that could be deployed on a commercial scale. We will evaluate different germplasm to see if some genotypes are particularly rich sources of hatching factors. We will examine ways to increase the activity of root exudate. In the Moscow greenhouses, we will test the efficacy of enriched, crude root exudate to cause a suicide hatch in cysts placed in pouches, in pots containing soil similar to the soil types found in Eastern Idaho. We will explore ways to increase the efficacy of potential trap crops, concentrating on S. sisymbriifolium, including ways to increase its root mass to allow better control in infested fields (ie more root mass, deeper root growth) and confirm that any potential trap crop does not allow reproduction of the Idaho G. pallida population.

3. Progress Report:
This is the final report for this project. We used Agrobacterium rhizogenes to generate naturally genetically modified sticky nightshade plants that have considerably greater root growth when grown in pots in the greenhouse compared to wild type plants. We established that APHIS will not regulate such plants as transgenic, because they were generated using a natural process. We supplied over 200 of these plants from tissue culture to cooperators in Idaho and Oregon that we are working with to characterize agronomic traits and host range. We have been trying to identify ways that large amounts of hatching factors can be partially purified and used to treat soil directly. For this approach to be effective, it would have to work on a commercial scale and have the ability to treat 1000s of acres. We have been working on ways this might be accomplished and working towards more clearly understanding the extent to which hatching factor production can be scaled up. We are exploring whether the Globodera population discovered in Oregon can be used to facilitate purification of hatching factors that stimulate the Idaho population to hatch. Our research corresponds to sub-objective 1.B. of the related in-house project, "Develop germplasm with resistance to pests and diseases, establishing effective and efficient screening protocols, determining range of expression, inheritance, heritability, and discover molecular markers, while mapping genetic factors where possible and useful". Our Oregon collaborators are able to use “field cysts” that seem to give more quantitative data than the cysts we’ve been using at the U. of Idaho, which are raised in the greenhouse. We generated root exudates or partially purified fractions from numerous samples using column chromatography or HPLC and provided these samples to collaborators in Oregon to test for hatching activity. We are evaluating the data obtained with the Oregon population to compare the data we generated with the Idaho population using the same extracts.

4. Accomplishments

Last Modified: 10/16/2017
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