Fig. 1. A. fumigatus GT4C regulates GAG synthesis.

a, Biofilm formation assay on an abiotic surface with A. fumigatus wild type (WT) and Δgt4c. Representative image. b, c, Quantification of biofilm formation on an abiotic surface (b) in absence or (c) presence of exogenous GAG in Brian medium by crystal violet absorbance at 600 nm wavelength (A_{600 nm}). (b, n = 5 and c, n = 6 biologically independent samples; ****P < 0.0001; unpaired two-tailed t-test). Data are mean +/− SEM. Exact P values are presented in Extended Data Table 2. d, Scanning electron microscopy of A. fumigatus WT or Δgt4c hyphae surface incubated for 20 h in Brian medium (green arrowhead indicates ECM composed of GAG). e, Immunofluorescence staining of fungal GAG (green) on mycelium of A. fumigatus WT or Δgt4c. (d,e, Representative images, n ≥ 2 independent experiments). f, Representative structure of A. fumigatus GAG. g–i, Percentage of monosaccharides in (g) alkali insoluble or (h) alkali soluble cell wall fractions and (i) percentage of monosaccharides or proteins in culture supernatant from WT and Δgt4c A. fumigatus (n = 2 biologically independent samples; bar depicts mean). GalN, galactosamine; GlcN, glucosamine; n.d., not detected. Scale bars, (d) 1 μm; (e) 10 μm.