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.
Coordinated changes in gene expression mediate legume crop plant adaptation and acclimation to soil nutrient deficiencies. A major limiting nutrient throughout much of the world is phosphorus. MicroRNAs have been reported to be involved in signaling plant nutrient deficiencies and turning on suites of genes involved in acclimating to deficiency conditions. The microRNA399 is known to be induced during phosphorus deficiency. In previous studies of common bean and lupin we found that light and sugars from photosynthesis modulated phosphorus deficiency induced gene expression. The effect of light and sugars on microRNA production is unknown. We discovered that darkened and/or shaded plants were impaired in the induction of microRNA399 even under phosphate deficiency conditions. These results show that there must be a form of crosstalk in plant nutrient deficiency signaling that involves light, sugars from photosynthesis, microRNA, and the induction of genes involved in acclimation to stress. The ADODR had regularly scheduled meetings with the collaborator to discuss research findings.