FIG. 5.

Effect of spacer insertions between the putative VsrD and PhcA binding sites on expression of P_xpsR. Various lengths (4, 118, and 232 bp) of spacer DNA were inserted into the XbaI site (at −183) in P_xpsR on fusion plasmid pRLZ1 (Fig. 2) to create plasmids pRLZ11 to pRLZ13. Expression directed from each P_xpsR derivative was monitored in wild-type (WT), vsrD mutant (AW-D5), and phcA mutant (AW1-80) strains of R. solanacearum by measuring LacZ activity as described in Table 2, footnote a. Striped and hatched boxes represent binding sites for VsrD and PhcA, respectively.