Sporangium of Parasitella parasitica. Image by Kerry O'Donnell

Parasitella are mycoparasites of other fungi including Mucorales order fungi. P. parasitica grows well in axenic culture on ordinary fungal culture media (Schipper 1978). 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 parasitism of P. parasitica is dependent on the mating type of the host, P. parasitica (+) will parasitize only Absidia glauca (-) or any other suceptable species of the Mucoraceae that is of the (-) mating type. 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).

Genome sequence for this lineage provides additional understanding of the phylogenetic diversity of the Mucoralean fungi and sampling of major Families within the order. As a mycoparasite, one of several potentially independently evolved instances within the fungi, it will provide additional perspective on the evolution of metabolism and parasitism within this order of early branching fungi.

Source: http://zygomycetes.org/

References
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.

Schipper, M.A.A. 1978. On the genera Rhizomucor and Parasitella. Studies Mycol. (Baarn) 17:52-71.