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. 2020 Apr 14;9:e55587. doi: 10.7554/eLife.55587

Figure 5. Flo11A-mediated separation of competitive yeast strains.

(A) Competitive biofilm assays. Yeast strains expressing the indicated Flo11 variants were mixed in a 1:1 ratio and were grown to a mat biofilm for three weeks. To distinguish between competing Flo11 variants, strains were tagged by expression of either GFP (green color) or RFP (red color). Homotypic and heterotypic Flo11 combinations are indicated. Each Flo11 variant was assayed using two independent strains tagged by either GFP or RFP, to test robustness to the fluorescence marker. Scale bar corresponds to 1 cm. (B) Quantification of presence of competing Flo11 strains from A present at the outer biofilm edge (Figure 5—source data 1). For quantification of the genotypic ratio, the amount of the signal produced by the superior strain a (bold) was divided by the amount of the signal from the inferior strain b (regular). Average ratios are presented using five different categories as indicated. For each combination of competing strains, at least two biological replicates of independently obtained clones were assayed.

Figure 5—source data 1. Quantification of RFP and GFP signals in mixed biofilms presented in Figure 5.

Figure 5.

Figure 5—figure supplement 1. Quantitative analysis of biofilms upon competitive assays.

Figure 5—figure supplement 1.

Yeast strains expressing the indicated Flo11 variants were mixed in a 1:1 ratio (OD600 of cells) and grown to a mat biofilm for three weeks. Competing yeast strains were tagged by expression of either GFP (green color) or RFP (red color). Homotypic and heterotypic strain combinations are shown separately as indicated. Each Flo11 variant was assayed using two independent strains tagged by either GFP or RFP, to test robustness to the fluorescence marker. After three weeks of development, biofilms were photographed using GFP and RFP filters, and resulting pictures were further processed for quantification of biofilms sizes and for spatial analysis of green and red signals within biofilms (Figure 5—source data 1). (A) Spatial distribution of competing yeast strains within biofilms. Curves in the depicted graphs show the red/green signal ratios in relation to the distance from the center (inoculation spot) of the biofilms. Replicates are shown by different color. (B) Biofilm size for each combination of competing yeast strains is shown by bars indicating the total area covered by the different biofilms in cm2. Error bars indicate standard deviation. (C) Relative presence of competing strains within whole biofilms is shown as the ratio of the total amount of red signals versus the total amount of green signals within biofilms. Error bars indicate standard deviation. (D) Relative presence of competing strains at the outer biofilm edge is shown as the ratio of red versus green signals present along a line in distance of 50 pixels to the biofilm edge. Error bars indicate standard deviation.