Fig. 8. Immunogold localization of TbSP1 in ectomycorrhizas. (A) Light microscopy, cross-sectional view of a Tuber–hazelnut ectomycorrhiza. Arrowheads indicate the Hartig net penetrating between root cells. The epidermis (e), the cortex (c) and the central cylinder (cc) of the root as well the fungal sheath (mantle, m) are also indicated; bar = 15 µm. (B) Immunogold TEM analysis of mantle-forming hyphae (m) labeled with the anti-TbSP1 antibody. The immunonegative, electron-opaque material separating the hyphae is marked with an asterisk; n, nucleus. Arrows point to TbSP1-associated gold granules accumulated in the chitin-containing, inner cell wall layer (bar = 1.3 µm). Gold granules in the inner cell wall layers of a growing extramatrical hypha (h) and of hyphae progressing between root cells in the Hartig net region are shown in (C) and (D) (bars = 0.4 µm). Also apparent in (D) is the absence of immunopositive material in the host cell walls (w). A control section from which the primary anti-TbSP1 antibody was omitted is shown in (E) (bar = 0.5 µm).