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. 2016 Jun 2;7:11814. doi: 10.1038/ncomms11814

Figure 6. Modelling of PO distribution and mixing.

Figure 6

(a) Predicted PO distribution, given as intensity profile along the apical 30 μm of hyphal cells. −DT, no directed transport; −AD, no AD; −PD, no PD; and combinations. POs are evenly distributed in control cells (upper left). In the absence of AD and DT, POs cluster at the hyphal tip (upper middle, −DT/−AD). With no PD, no clustering occurs (upper right; −DT/−AD/−PD). MT-associated processes do balance, as no clustering occurs when only PD is excluded (lower left; −PD). In the absence of AD, POs are still evenly distributed (lower middle; −AD). When active transport is absent, slight aggregation of POs towards the growing tip is predicted (lower right; −DT). Polar clustering is stronger when AD and DT are excluded (upper middle, compare with lower right), suggesting that both processes cooperate in distributing POs. Colour coding matches b,c. (b) Predicted PO mobility over long distance under various conditions (−AD, no AD; −DT, no DT; −PD, no PD; and combinations of these). The average time required for a PO to move from the tip (indicated by START) to sub-apical regions is indicated. Data points are provided as mean±s.e.m., n=100–2,000 simulations. Mobility is drastically impaired when AD and DT are excluded. It is also noteworthy that curves for ‘noPD' and ‘no AD' are covered by the control curve. (c) Predicted PO mobility over short distances under various conditions (−AD, no AD; −PD, no PD). The average time required for a PO to move from the tip to sub-apical regions is indicated. Data points are provided as mean±s.e.m., n=2,000 simulations. AD is required for rapid mobility over short distances. It is noteworthy that curve for control is covered by ‘no PD' (−PD) and therefore not visible. (d) Diagrams show projections of POs, mixed in a cylinder of 10 μm × 2 μm in diameter under various conditions, captured after 250 s. It is noteworthy that simulations started with 15 blue and 15 red POs, placed at either end of the field (see Supplementary Movie 7). Scale bar, 2 μm.