Fig. 4

Flow cytometry results on xylose 50 g/L (a, c, e and g) and no carbon source—YNB only (b, d, f and h) after 6 h.  The histograms represent: strains without biosensor (a and b), HXT1p (c and d), SUC2p (e and f) and TPS1p (g and h), respectively. Each control strain (a and b: 3751, c and d: 3752, e and f: 3755 and g and h: 3757) is presented with all its deletion derivatives: single (isu1Δ, hog1Δ, and ira2Δ), double (ira2Δisu1Δ and isu1Δhog1Δ) and triple (ira2Δisu1Δhog1Δ) deletion. The black line indicates the autofluorescence of each control strain. The red dotted line shows the Fluorescence Intensity (FI) of the repression condition of each control strain (see Additional file 1: Figures S2–S4 (0 h)). The red solid line indicates the autofluorescence of control strain 3751 under the same condition (a, b). The cultivations were performed in oxygen limited microtiter plates, but the results are highly similar to those of the anaerobic and aerobic shake flasks (Additional file 1: Figure S6 )