2011 Annual Report
1a.Objectives (from AD-416)
Conduct research to identify, characterize, and determine the function of genes involved in nitrogen fixation, nitrogen assimilation, phosphorus acquisition, and root development in Lupinus, Medicago, and Phaseolus.
1b.Approach (from AD-416)
1. Prepare cDNA libraries from various plant organs of the three legume species. Develop genomic libraries of the three species.
2. Use high throughput sequencing to evaluate transcriptome.
3. Sequence genes and prepare antibodies to the gene products.
4. Evaluate gene expression via RNA blots, immunoblots, enzyme assays, and in situ hybridization.
5. Characterize potential promoter elements for important genes related to the processes cited above.
6. Modify expression of relevant genes via overexpression, antisense, and/or RNAi approaches.
The research reported in this project addresses Objective 2 of the parent project 3640-21000-028-00D: Develop and employ RNA interference-mediated gene silencing to identify the functional role of genes involved in phosphorus and nitrogen acquisition and metabolism in root tissues of legumes such as common bean, pea, and lentil.
Phosphorus (P) is a non-renewable fertilizer resource required for plant growth and development. Easily mined P is expected to peak between 2040 and 2060. Developing crop plants that are more efficient at acquiring and using P is critical for world agriculture. To address plant genes responsive to and regulating P acquisition and use, ARS researchers in St. Paul, Minnesota, in cooperation with collaborators at the University of Minnesota identified three genes in white lupin involved in root response to P deficiency. The genes glycerophosphodiesterase (GPXPDE) 1 and 2 and tonneau1 (TON1) encode proteins involved in P-stress root hair formation and P-stress lateral root development, respectively. Reporter gene constructs for GPXPDE1 and 2 and TON1 were used to transform white lupin roots and determine cellular patterns of gene expression. The results showed that phospholipids and cell plate formation play major roles in root hair and lateral root development. The Authorized Departmental Officer's Designated Representative (ADODR) had regularly scheduled meetings to discuss research objectives, approaches, and findings.