In silico sigma 70 promoter analysis. The upstream sequences of the genes were analyzed by Patser software using an S. meliloti sigma 70 factor weight matrix . aat - upstream region of the aat gene; glnB - upstream region of the glnB gene; glnK - upstream region of the glnK gene; lac - lac promoter; W/P - negative control, 500 bp upstream of the eyfp gene of the plasmid pHREYFP. The S. meliloti promoter consensus is the first sequence. Nucleotides that match the S. meliloti consensus are in red, and those that match the most conserved residues of the S. meliloti promoter consensus (relative frequencies above 0.8) are in bold. Gaps were inserted to preserve the alignment at the regions of the promoters.