Table 1.
Product/expression* | Amendment† | Bacterial cultures‡ | ||
---|---|---|---|---|
ΔphlAΔpltM | ΔphlAΔpltM + ΔphlAΔphlDΔpltA | ΔphlAΔphlDΔpltA | ||
Pyoluteorin | None | BD | 6.2 ± 1.8 nmol/g | BD |
DAPG | None | BD | BD | BD |
Relative GFP | None | 34.6 ± 2.3 | 137.4 ± 3.4§; 214.7 ± 11.2¶ | 27.6 ± 1.9 |
PG (10 nM) | 37.6 ± 3.1 | NT | 133.3 ± 6.4 | |
PG-Cl (1 µM) | 261.0 ± 13.3 | NT | 308.6 ± 21.8 | |
PG-Cl2 (10 nM) | 128.2 ± 10.7 | NT | 268.4 ± 16.2 |
*The mutants were cultured for 3 d on a NAGly plate to determine production of secondary metabolites, and for 20 hr in NBGly broth to determine expression of pltL::gfp from the reporter construct pL-gfp (Figure 1E). The co-culture was prepared by mixing the two mutants at a 1:1 ratio.
†PG, PG-Cl or PG-Cl2 was amended in the mutant cultures to test their influences on the expression of pltL::gfp. The concentrations of the tested compounds are shown in parenthesis.
‡Secondary metabolites were extracted from the agar plate and the concentrations of DAPG and pyoluteorin were determined by HPLC. Expression of pltL::gfp was monitored and recorded as relative GFP (fluorescence of GFP divided by OD600). §The ΔphlAΔpltM mutant, but not the ΔphlAΔphlDΔpltA mutant, contains pL-gfp in the co-culture. ¶The ΔphlAΔphlDΔpltA mutant, but not the ΔphlAΔpltM mutant, contains pL-gfp in the co-culture. Data are presented as mean ± standard derivation. Mean values are calculated from three biological replicates. BD = below detection. NT = not tested.