PROTEOMIC AND TRANSCRIPTOMIC APPROACHES TO STUDY GLOBAL GENOME EXPRESSION IN RHIZOBIUMETLI AND SINORHIZOBIUMMELILOTI

摘要

Two global approaches have been used to study the free-living state of the symbiotic species, Rhizobium etli and Sinorhizobium meliloti, as well as the R. etli-Phaseolus vulgaris interaction. The proteome of R. etli was examined to determine the enzymatic reactions and cell processes that occur in the free-living state (fermentative, aerobic metabolism, and symbiosis with legume plants). All the detectable protein spots on the two-dimensional (2-D) gels between pH 3-10 were analyzed. In total, we identified 1,518 proteins. Using a combination of 2-D gel electrophoresis, peptide mass fingerprinting, and bioinformatics, our goal is to identify: (i) biofilm-, aerobic- and fermentative metabolism-, symbiosis- and stress-specific proteins; and (ii) the biochemical pathways active under different conditions tested. Using the databases of the genome sequences from R. etli and S. meliloti genomes and the software "Pathway tools", we constructed in silico the pathways and metabolic reactions potentially functional in both bacteria. We called these databases Sinocyc (S. meliloti) and Rhizocyc (R. etli). Using this definition, 46 pathways involved in many common anabolic and catabolic cellular processes of small molecule metabolism can be considered active in R. etli under the conditions examined.