Comparative study of the holdfast structure in four Trichomycetes

An electron microscope study reveals considerable variation in the holdfast structure by which the fungal thalli of Trichomycetes attach to the gut lining of their arthropod hosts. Enterobryus attenuatus (Eccrinaceae) has a compound holdfast system where the holdfast substance is secreted through a reticulate ring complex located at the base of each individual thallus. The ring complex is rich in polysaccharides, as is the outermost layer of the cell wall. Enterobryus elegans produces large, single holdfasts with a fibrous matrix containing numerous parallel channels, some of which open to the gut lumen. Genistellospora homothallica (Legeriomycetaceae) has a dense and homogeneous biconcave holdfast, whereas Pennella angustispora, belonging to the same family and found in the same host, secretes an amorphous cementing substance throughout the length of the basal cell wall.