Chemical components and their locations in the Verticillium fungicola cellwall

The chemical structure of cell walls and fractions of Verticillium fungicol a, a pathogen ofAgaricus bisporus, as well as their corresponding ultrastru ctures were studied. There are at least three chemically distinct types of carbohydrate polymers: one yielding mannose with lower amounts of galactose and glucose (glucogalactomannan), another one composed mainly of glucose ( glucan), and a third one containing only N-acetylglucosamine (chitin). Atte mpts were made to locate these materials in situ by comparing electron micr ographs of shadowed and sectioned cell walls, and also by indirect immunofl uorescence. It was shown that none of these polymers constituted a complete ly physically distinct layer, but there seem to be different solubility pro perties in the outer, inner, and intermediate layers. It was also shown tha t fibrillar material (chitin) embedded in cementing glucan constituted the residual inner fraction of the original wall material. Indirect immunofluor escence showed the location of a significant amount of glucogalactomannan o n the surface of the walls in which rodlet structures were visualized by el ectron microscopy.