Fig. 4: SV transport towards the growing hyphal tip in T. reesei.

a SVs, labelled with TrmsGFP₂-Sec4, in the 1^st hyphal cell in T. reesei. Note that the endogenous sec4 gene of sec4 was fused to the fluorescent tag; consequently, all SVs are fluorescently labelled. The plasma membrane is labelled by TrmCherry-Sso1 (red). Scale bar = 20 µm. b Bidirectional motility of SVs within the 1^st cell. Note that the contrast-inverted kymograph was taken at a rear region of the cell as high density of SVs in the apical region of the 1^st cell challenge visualisation of SV motility. Horizontal scale bar = 2 µm; vertical scale bar = 3 s. c Quantitative analysis of anterograde motility of SVs in the tip cell and 5 subapical cells. Numbers were estimated in un-bleached hyphae; the region of measurements in subapical cells were located 10 µm behind the septum; numbers in the 1^st cells were determined in regions located 10 µm behind the tip. Sample size n = 40 for 1^st and 2^nd cell, n = 33 for 3^rd cell, n = 37 for 4^th cell and n = 35 for 5^th and 6^th cell from 2–3 independent experiments. d Contrast-inverted kymographs showing the effect of inhibitors of the cytoskeleton motility of SVs, labelled with TrmsGFP₂-Sec4. Motility ceases when microtubules are depolymerised (benomyl), but continued in the absence of F-actin (LatA). Cells were treated 30 min with 10 µM of benomyl, 10 µM latrunculin A or the corresponding amounts of the solvent DMSO (control). Horizontal scale bar = 3 µm; vertical scale bar = 3 s. See also Supplementary Movie 7. e Kymograph showing motility of SVs, labelled with TrmsGFP₂-Sec4 (green), across the 1^st septum, labelled with TrmCherry-Sso1 (red). Horizontal scale bar = 1 µm; vertical scale bar = 1 s. See also Supplementary Movie 8. f Quantitative analysis of anterograde and retrograde motility of SVs across septa in hyphae. Only directed motility was included, passive drifting of SVs through the septum was not considered. Sample size n = 33 for 1st septum, n = 34 for 2^nd and 5^th septum, n = 37 for 3^rd septum and n = 35 for 4^th septum from 2 independent experiments. Results were confirmed in 3 (a, b) and 2 (d, e) independent experiments. Bars in (c, f) represent mean ± SEM; sample sizes are indicated. Statistical comparison with in (f) used Student’s t testing testing; n.s. = non-significant difference, *= two-tailed P-values 0.0444 (3^rd) and P-values 0.0181 (4^th). All data were obtained from growing hyphae and are provided in the Source Data File.