Les interfaces des mycorhizes. Un exemple d'interactions pariétales

Abstract

The structure of the interface between the two partners is very different according to the different types of mycorrhizae. In ectomycorrhizae, the interface is formed by the superposition of the fungal wall and the cortical cell walls of the host plant. The parietal structures of the partners are modified to some degree, with, as a result, the formation of a glycoproteic cement involved in the cohesion of both organisms. In veslcular-arbuscular (VA) endomycorrhizae, the arbuscule hyphae walls are transformed under host-cell action. Moreover, they are lined with an apposition layer, produced by the host cell, similar to a wall and construed as a manifestation of a defense response to endophyte invasion. Other types of endomycorrhizae such as ericoid mycorrhizae, orchid mycorrhizae, Terfezia mycorrhizae, present an interface organization identical to that of VA mycorrhizae. In Monotropa ectendomyccorhizae, the intracellular formations are non-branched hyphae. As in endomycorrhizae, the fungal wall is covered with a dense and continous apposition layer with finger-like expansions. Thus, regardless of the type of mycorrhlza, partners are always separated by a mixed apoplasm, the structure of which is the result of interactions between the two partners. © 1991 Taylor & Francis Group, LLC.