Fig 2.

(A) Physical and genetic map of the R. leguminosarum bv. trifolii 24.2 pssB-pssA region. The light gray and black arrows below the map show the directions of pssB and pssA transcription, respectively. Promoters P1, P2, and P3 are marked by white rectangles. cAMP-CRP boxes, IRO boxes, and Pho boxes are shaded in black, dark gray, and light gray, respectively. ICE box and RosR motifs are left- and right-striped rectangles, respectively. B, BamHI; E, EcoRI; H, HindIII. (B) Transcriptional activity of pssA promoters assayed in E. coli DH5α and 24.2 strains carrying the pMP220 plasmid with different fragments of the pssA upstream region fused with the promoterless lacZ gene. E. coli strains were grown in LB medium, and strain 24.2 derivatives were grown in 79CA medium supplemented with 1% glycerol for 24 h. β-Galactosidase activities shown are means of five independent experiments with standard deviations.