Figure 1

Time course of colonization of grapevine cv/hybrids by P. viticola strain G. The pathogen structures (red colour) inside the leaf tissues (green colour) of susceptible (a, d, g, j, m) and resistant (b, c, e, f, h, i, k, l, n, o) grapevine plants following inoculation with G strain and aniline blue staining are represented. Pathogen diffusion was monitored 1 (a-c), 2 (d-f), 3 (g-i), 4 (j-l) and 7 (m-o) days after inoculation. (a) Substomatal vesicle (sv) with primary hypha (h) and first haustorium (harrow head) in the substomatal cavity of the leaf tissues of hybrid 18006. (b) Substomatal vesicle under an infected stoma of grapevine line 18096. (c) Callose depositions (asterisks) on the spongy mesophyll cells under an infected stoma. (d,e) Branched hyphae with haustoria (arrowhead) developing from the substomatal vesicles inside susceptible cv Chardonnay and resistant hybrid 18120. (f) Low diameter hypha (arrow) in the resistant cv Bianca. (g) Regular diffusion of the mycelium inside an infected area of Chardonnay. (h) Reduced colonization of the leaf tissues of the resistant hybrid 18103. (i) Callose on the hyphal wall inside the resistant hybrid 18120. (j) Complete colonization of the infected areas of cv Chardonnay. (k) Limited diffusion of P. viticola mycelium that in some cases was covered by callose (asterisk). (l) Degenerated mycelium (left) under a necrotic area and regular hyphae (arrows) inside the same infected leaf of the intermediate hybrid 18090. (m) Sporangiophores emerging from Chardonnay. (n) Mycelium diffusion inside Bianca. (o) Detail of an hypha covered by callose (asterisk). C = chloroplast, LV = leaf vein. Scale bar = 50 μm.