The sporangia of Caulochytrium (circles) attached to the hyphae of Sordaria. The slipper shaped flagellated zoospores can be seen and these are the single cells that were used for sequencing. Image credit: Olive L.S. (1983)

Caulochytrium protostelioides is a mycoparasite of Sordaria and represents an unsampled lineage on the Fungal tree of life. Other species in the genus are known as parasites of Cladosporium. The fungus is zoosporic and uniflagellate, and is notable among other zoosporic fungi because it produces aerially dispersed sporangia (Olive 1983).

C. protostelioides has been selected as part of a Fungal single-cell genome sequencing pilot project and was sequenced using single-cell methods. A separate annotation, "Caulochytrium protostelioides ATCC 52028", was produced using non-single-cell methods.