LOCALIZATION OF BETA(1-3)-GLUCAN IN WALLS OF THE ENDOMYCORRHIZAL FUNGI GLOMUS-MOSSEAE (NICOL AND GERD) GERD AND TRAPPE AND ACAULOSPORA-LAEVIS GERD AND TRAPPE DURING COLONIZATION OF HOST ROOTS

Previous studies showed that cell walls of endomycorrhizal fungi belonging to the Acaulosporaceae and Glomaceae contain beta(1-3) glucan polymers as well as chitin. Indirect immunolabelling with monoclonal and polyclonal antibodies has been used to investigate the distribution of these structural polysaccharides in cell walls of Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe and Acaulospora laevis Gerd. and Trappe as they interact with pea and tobacco roots, respectively. The beta(1-3) glucans were detected in the walls of external hyphae, and of hyphal coils and intercellular hyphae developing in outer root tissues. The glucan component was alkali-insoluble but treatment with chitinase resulted in solubilization of most of the beta(1-3) glucans from the fungal wall. A decrease in immunolabelling was associated with thinning out of the hyphal wall as the fungi colonized deeper in the host root, and beta(1-3) glucans could not be detected in walls of intercellular hyphae or arbuscules in the parenchyma cortical tissue. The molecular configuration of cell walls of G. mosseae and A. laevis is discussed in relation to fungal morphogenesis and the symbiotic state in endomycorrhiza.