Parasitella
PARASITELLA Bainier, 1903 (Bull. Soc. Mycol. France 19:153); 1 spp. (Schipper, 1978—monograph).
Parasitella produces simple or branched sporangiophores that arise directly from the substrate. Sporangia terminate each branch that are more or less globose, columellate, apophysate, multispored, and have a moist wall. Sporangiospores are ellipsoid. Zygospores have a rough zygosporangial wall and opposed, appendaged suspensors. The only known species, P. parasitica, is heterothallic. In nature it is a gall-forming parasite of mucoralean fungi of the opposite mating type.
Type species: P. parasitica
Species of Parasitella:
P. parasitica (Bainier) Sydow, 1903 (Ann. Mycol. 1:371).
Parasitella grows well in axenic culture on ordinary fungal culture media (Schipper, 1978). Parasitella parasitica is similar to Mucor hiemalis except that the colony is lighter in color and it grows slower. When parasitizing a suitable host (a mucoralean fungus of the opposite mating type), P. parasitica produces narrow hyphae that form septa to delineate the region behind the regions of contact. These contact areas enlarge and the wall between them dissolves, those of the host forming fingerlike growths and the apex of the parasite mycelium becomes globose; the nuclei of the both the host and parasite mix (Schipper, 1978). The mature galls were thought to be the zygospores of Dispira americana (Syn.: = D. cornuta) although Thaxter (1895) said they resembled the galls formed by Chaetocladium; they are probably the galls of P. parasitica (Blakeslee, 1904). The parasitism of P. parasitica is dependent on the mating type of the host, P. parasitica (+) will parasitize only Absidia glauca (-) or any other susceptable species of the Mucoraceae that is (-) . Zygospore formation in Parasitella requires the presence of the appropriate host because because trisporic acid levels are low in P. parasitica (Wöstemeyer et al., 1995).
Bibliography
Blakeslee, A.F. 1904. Sexual reproduction in the Mucorineae. Proc. Am. Acad. Arts Sci. 40:205-319.
Schipper, M.A.A. 1978. On the genera Rhizomucor and Parasitella. Studies Mycol. (Baarn) 17:52-71.
Thaxter, R. 1895. New or peculiar American Zygomycetes. I. Dispira. Bot. Gaz. (Crawfordsville) 20:513-518.
Wöstemeyer, J., A. Wöstemeyer, A. Burmester, and K. Czempinski. 1995. Relationships between sexual processes and parasitic interactions in the host-pathogen system Absidia glauca—Parasitella parasitica. Can. J. Bot. 73 (Suppl. 1):S243-S250.
Updated Mar 13, 2005