Project Number: 3640-21000-024-00
Project Type: Appropriated

Start Date: Mar 20, 2006
End Date: Mar 19, 2011

Objective:
Nitrogen (N) and phosphorus (P) are the two most limiting and costly macronutrients required for crop growth. The long-term goal of this research is to improve N and P acquisition and/or use in crops. Utilizing comparative functional genomics and gene silencing approaches, the objectives are to: 1) use discoveries from Medicago truncatula, a model legume, root and root nodule genomics to characterize and improve the biological efficiency of symbiotic nitrogen (N2) fixation in alfalfa; 2) develop and employ RNA interference (i)-mediated gene silencing to identify the functional role of genes involved in P and N acquisition and metabolism in root tissues of legumes such as common bean, pea, and lentil; and 3) determine genes regulating protein and oil accumulation in soybean through whole genome transcript analysis and functionally characterize gene candidates.

Approach:
Alfalfa genes important in nitrogen fixation will be identified from the Medicago EST and genome sequencing projects. The sequence of 5'-promoter regions of selected genes will be identified from both alfalfa and M. truncatula. The expression of selected root nodule genes will be silenced through RNA interference. Nodules from plants containing RNA interference will be characterized for nitrogen fixation and nodule development. The Medicago truncatula gene chip will be used to assess global gene expression in alfalfa. BSL-1; Recertified June 4, 2008.