Fig. 4.

Gene promoter activity in P. fluorescens CHA0 and its psoR mutant CHA0PSOR harboring plasmid pMPXooPIP, which contains the X. oryzae pv. oryzae pip promoter fused to a promoterless lacZ gene. In the presence of macerated wheat and rice leaves, there was a significant increase in promoter activity which was less so when the gene promoter fusion was harbored in CHA0PSOR. Macerated cucumber leaves, on the other hand, did not alter gene promoter activity. All measures were performed in biological triplicates, and the mean value is given.