Figure 6.

Accumulation of GFP-PEN1 at infection sites takes different forms. Three-dimensional reconstructions of image stacks. Fungal structures are in red, GFP-PEN1 or CFP-SYP122 (D) are shown in green. Images were taken 17-24 hpi with Bgh (A-D and F-I) or E. chiccoracearum (E). (A-C) Different projections of the same sample showing accumulation of GFP-PEN1 at papillae. B is the same as A, but without the red channel. (B) Accumulation of GFP-PEN1 inside papillae (p, compare to G and H where rings are seen), more clearly seen in serial sections (our unpublished results). Arrow points to the penetration hole, in which no GFP-PEN1 is seen. (C) Side view of A. (D) CFP-SYP122 localization to the plasma membrane (arrowheads) and to papillae (arrow). (E) Localization of GFP-PEN1 to papillae (p) upon infection with the host powdery mildew. GFPPEN1 also localizes to an endomembrane compartment, which forms clouds close to the infection site (arrowheads). (F) Accumulation of GFPPEN1 at the cell surface at the point of contact with the appressorium. The novel GFP-PEN1 domain is contiguous with the plasma membrane, too faint to be seen in the image. (G) A bright ring of GFP-PEN1 is seen. Note the relative intensity of the ring compared with the adjacent plasma membrane. In 3D reconstructions, this ring forms the rim of a cup-shaped structure (our unpublished results). (H) Concentric rings of GFP-PEN1 fluorescence form a bull's eye at the penetration hole. Arrow points to an endomembrane compartment, roughly 1 μm in diameter. (I) The second ring of the bull's eye (arrowhead in H and I) is the rim of a hollow cup-shaped structure. a, appressorium; p, papilla. Scale bar, 5 μm in F, 10 μm in all other panels.