Figures 1a-c. Fig. 1a. Five sporophores of Ramicandelaber brevisporus growing on the agar surface. The fertile portion of the sporophore is erect whereas the long sterile region is growing along the substrate. Fig. 1b. Fertile region of the sporophore of R. brevisporus with typical basal rhizoids and four levels of spore formation. Fig. 1c. Magnified view of the sporulating region of a sporophore showing the sporocladia (sc), pseudophialides (p) and pair of merosporangiospores (s). Credit: Gerald Benny, Matthew Smith.

Ramicandelaber brevisporus CBS 109374

Ramicandelaber is the second largest genus in the Kickxellales (Kickxellomycotina) with four species. Ramicandelaber brevisporus is uncommonly observed because its sporophore is extremely small and grows close to the agar in axenic media. The fertile portion of the sporophore is erect but the extremely long sterile apical region grows along the substrate. Ramicandelaber is the only genus in the Kickxellales that forms rhizoids, small branching hyphae that help to anchor sporophores to the substrate. Members of the genus Ramicandelaber have only been isolated from soil. Ramicandelaber brevisporus was initially isolated in Japan but other Ramicandelaber species have been found in Taiwan and Florida (USA). All members of the Kickxellales are saprobes except Martensella, a genus of putative mycoparasites.

Molecular phylogenies that have been conducted thus far suggest that Ramicandelaber may actually represent a unique lineage that is distinct from both Kickxellales and Harpellales and may represent a separate family or order of fungi.

Members of the Kickxellomycotina are unique in that they regularly form septa containing plugs. Members of the other three subphyla and the single zygomycotan phylum, Entomophthoromycota, do not produce regularly septate hyphae.

Genome sequencing of Ramicandelaber brevisporus will increase our sampling of fungal diversity, improve our understanding of the evolutionary relationships within Kickxellomycotina, and help to elucidate the ecological role that this group of soil-dwelling fungi may play in carbon cycling and ecosystem function.