Infection of Brachypodium distachyon by Formae Speciales of Puccinia graminis: Early Infection Events and Host-Pathogen Incompatibility
Figure 3
Early events in the infection of Brachypodium inbred line Bd1-1 by Puccinia graminis formae speciales.
Fluorescence micrographs of longitudinal leaf sections show the fungal penetration sites and formation of infection structures according to time in hours post-inoculation (left side). The isolates P. graminis f. sp. tritici (Pg-tr), P. graminis f. sp. lolii (Pg-lo), and P. graminis f. sp. phlei-pratensis (Pg-pp) used for inoculation are indicated at the top of the figure. Fungal tissue was stained with Uvitex 2B (chitin specific) which exhibits blue fluorescence under UV-light. Structures are labeled as follows: u, urediniospore; g, germ tube; a, appressorium; s, leaf stoma; i, primary infection hyphae; v, substomatal vesicle; h, haustorium. Panels D, E, G and H show the formation of callose papillae below fungal penetration sites. Scale bar in panel L indicates 20 µm.