Submitted to: International Conference on Legume Genomics and Genetics
Publication Type: Abstract only
Publication Acceptance Date: 6/7/2004
Publication Date: 6/7/2004
Citation: Lara, M., Hernandez, G., Ramirez, M., Blanco, L., Silvente, S., Reddy, M.P., Vance, C.P. 2004. Omics approaches for analysis of nitrogen and carbon metabolism in Phaseolus beans. In: Legumes for the Benefit of Agriculture, Nutrition and the Environment. Second International Conference on Legume Genomics and Genetics, June 7-11, 2004, Dijon, France. p. 281. Interpretive Summary:
Technical Abstract: Research of our group is mainly oriented toward transcriptomics of bean in symbiosis with rhizobia. A cDNA library from RNA isolated from 15-day-old nodules of P. vulgaris cv Negro Jamapa 81 induced by R. tropici CIAT899 was prepared. Around 3,000 ESTs were sequenced from this library representing 1,798 individual genes. In concordance with the nodule metabolism, most abundant ESTs involved in carbon and nitrogen metabolism are those related in sucrose metabolism, ammonia assimilation, and ureide synthesis. Based on this EST analysis, five metabolic routes; ammonia assimilation, nitrogen compounds synthesis, glycolisis, pentose phosphate pathway, PEP synthesis and TCA cycle, defined the main nodule metabolic profile. Macroarray analysis allows us to define those ESTs involved in these five metabolic routes with higher expression in nodules than in other tissues. In view of these analyses, key enzymes in nodule carbon and nitrogen metabolism were determined. Expression analysis of some of the selected key enzymes in different plant tissues revealed a tissue defined expression pattern of related metabolic processes rather than tissue specific expression pattern. These results could suggest regulatory elements involved in the expression of specific metabolic process whose expression is mainly determined in a tissue specific manner. Also we have identified the putative regulatory elements in the promoters of selected nodule-enhanced genes. Sequence analysis revealed the presence of the nodulin-specific motifs (AATAA, AAAGAT, CTCTT) in all the nodule-enhanced gene promoters of P. vulgaris. In addition, in these promoter sequences, putative regulatory elements responsive to phytochrome, light, nitrogen/nitrate, sugars, auxin, ethylene, and water stress were also detected.