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United States Department of Agriculture

Agricultural Research Service

DUROY A. NAVARRE (ROY)

Research Geneticist

Potato: Nutritional Enhancement; Improved Disease Resistance, and Molecular Plant-Pathogen Interactions

Potato is the most important non-cereal in the world and is the fourth largest crop after wheat, rice and corn. It is an important part of the diet of over 1.5 billion people. A primary interest of our group is to maximize the nutritional potential of potatoes. Potatoes are the most eaten vegetable in the United States. Staple foods are uniquely positioned to be a major source of vitamins and phytonutrients in the diet.  Because of the high consumption, a nutritionally maximized potato would be a major source of dietary phytonutrients and health-promoting compounds. We are using multiple complimentary approaches towards this goal, including LCMS and GCMS targeted metabolic profiling of diverse potato germplasm to identify genotypes particularly rich in desirable compounds. We are using molecular approaches for phytonutrient manipulation, including phenylpropanoids and folate.  We are also working with potato breeders to use the results of our metabolic profiling to develop new lines through traditional breeding.

Tuber phenylpropanoid metabolism is a major lab interest. Phenylpropanoids are the major antioxidants in many potato genotypes and have additional health promoting effects. Furthermore, phenylpropanoids have important roles in plants, including disease/pest resistance. We are trying to understand the mechanisms that control tuber phenylpropanoid content. Tuber phenylpropanoids appear to be developmentally regulated, with immature tubers typically having higher amounts. Baby potatoes are valued by consumers for their taste and are perceived as a premium product. Along with taste, the higher phytonutrient content of many “baby potatoes” is likely to appeal to many consumers. Tuber phenylpropanoids are modulated by environmental stimuli and various genes in the pathway are induced by various stimuli. One approach we are utilizing to understand phenylpropanoid metabolism is to metabolically engineer parts of the pathway and then examine how this affects tuber phenotype, metabolites and gene expression. A better understanding of tuber phenylpropanoid regulation can facilitate development of potatoes with superior nutrition.

Potato Cyst Nematode is another focus of our lab. This quarantine pest was found in Idaho in 2006. Even in the absence of a host, cysts can remain viable in the soil for 30 years. Each cyst typically contains hundreds of eggs that are stimulated to hatch by poorly defined compounds secreted by potato roots. Some other solanaceous plants also produce these “hatching factors” but most plants do not. We are working towards identifying these hatching factors and also identifying/developing potential trap crops that can be used to induce a “suicide hatch” of the nematode. If one can cause the eggs to hatch in the absence of a host, this has potential to be used to eradicate the nematode.

We are also interested in developing new potato genotypes with superior disease resistance, thereby decreasing the cost of production and reducing pesticide usage.  Scientific progress towards understanding how plants resist disease accelerated at a remarkable pace during the last decade, primarily due to the availability of increasingly powerful molecular and biochemical tools. Ultimately, such research will lead to the production of healthy, superior plants with high natural levels of disease and stress resistance—characteristics increasingly important not only for demanding consumers and profitability, but for feeding a burgeoning global population.

 

Primary Research Projects:

1.      Identification, characterization and development of potato varieties with enhanced nutritional properties.

2.      Characterization of secondary metabolites/small molecules in potatoes that have health-promoting properties or that are involved in pest/pathogen resistance. Interactions between primary and secondary metabolism and identifications of mechanisms that regulate tuber phenylpropanoid content.

3.      Analysis of potato disease resistance mechanisms and defense signaling.

 


Last Modified: 3/13/2012
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