Figure 3. Effect of phloroglucinol (PG) and Pf-5 culture supernatants on expression of pltL::gfp in P. fluorescens SBW25 (A, C), and P. protegens Pf-5 (B).

(A) Expression of pltL::gfp in SBW25 containing pRL-gfp. (B) Expression of pltL::gfp in wild-type (WT) Pf-5 and the ΔphlM mutant containing pL-gfp. (C) Expression of pltL::gfp in SBW25 containing pMRL-gfp. In each experiment, the concentration of PG is 10 nM, and the same volume of methanol was added to the bacterial cultures as a control. The supernatants of bacterial cultures were mixed with the fresh bacterial cultures at a 1:1 vol ratio to test their effects on pltL::gfp expression; WT-Sup, the culture supernatants of wild-type Pf-5; ΔphlD-Sup, the culture supernatants of a ΔphlD mutant. The expression levels of pltL::gfp were measured and recorded as relative GFP (fluorescence of GFP divided by OD₆₀₀). Letters above columns indicate treatments significantly different from one another, as determined by ANOVA analysis (p<0.05). Data are means of at least three biological replicates from a representative experiment repeated three times with similar results, and error bars represent the standard deviation of the mean.

DOI: http://dx.doi.org/10.7554/eLife.22835.006

Figure 3—figure supplement 1. Transcriptional profiles of pltM, pltR and the other genes in the pyoluteorin gene cluster of Pf-5.

Data were generated from our previous transcriptomic study (Clifford et al., 2016). The height of the black peaks indicates the expression levels of genes in the pyoluteorin gene cluster of the wild-type Pf-5 (Pf-5 combined coverage), the ΔphlAΔphlDΔphlG three-fold mutant (phlADG combined coverage), and the ΔphlAΔphlDΔphlG three-fold mutant grown in a medium containing 100 nM PG (phlADG_PG combined coverage). For the three strains/treatments, expression levels of genes are indicated in different scales to show the general expression profile of the whole gene cluster.

DOI: http://dx.doi.org/10.7554/eLife.22835.008

Figure 3—figure supplement 2. Production of pyoluteorin, DAPG and MAPG by P. protegens Pf-5 wild-type (WT), a ΔpltM mutant, and a pltM+ complemented strain.

Secondary metabolites were extracted from bacterial cultures incubated for 24 hr in NBGly. Data are means of three biological replicates from a representative experiment repeated twice with similar results, and error bars represent the standard deviation of the mean.

DOI: http://dx.doi.org/10.7554/eLife.22835.009