Ultrastructure of cyst-like fungal bodies in myxomycete fruiting bodies

Abstract

This is the first report on ultrastructural observations of nivicolous myxomycete fruiting bodies with cyst-like bodies. One specimen had immature fruiting bodies of a Lamproderma sp. just after spore cleavage. Using light microscopy and scanning and transmission electron microscopy, countless cyst-like bodies were observed inside of the developing spores, capillitium, columella and stalk. A second specimen consisted of mature fruiting bodies of L. echinosporum. Outward appearance of the fruiting bodies was normal with numerous cyst-like bodies inside the entire fruiting body. The cyst-like bodies in both myxomycete specimens have a common morphology: 5-6 m in diam, being transparent under light microscopy and densely warted by SEM and TEM observation. The partial sequence of the 18S rDNA gene of the first specimen suggested that cyst-like bodies were in the Cryptomycota (including Rozellida), placed at the root of a fungal clade.