Sclerotia

Sclerotia are hard, compact masses of fungal mycelium that usually form in soil or plant tissue. They are thought to serve as resting structures that can survive and remain quiescent in adverse environmental conditions until circumstances become favorable for fungal growth. Some sclerotia have been used as food and medicine for a long time in human history.

The fungus Cenococcum geophilum forms sclerotia in forest soils. It is one of the most common ectomycorrhizal fungi encountered in forest ecosystems. Its geographic distribution is cosmopolitan and it is found in ecosystems with a wide range of environmental conditions, very often in high numbers. Because of its wide distribution and abundance in forest soils, it is probably one of the most well-studied fungal species. 

A new study suggests that Cenococcum sclerotia act as a substrate for many other fungi. A team of American and Japanese researchers used DNA Barcoding  to document the fungal communities growing inside sclerotia that were collected from forest soils. They were able to detect at least 85 other fungal species in sclerotia across many sites which suggests that these fungi may be active parasites of Cenococcum sclerotia or at least use sclerotia as a nutrient source. 

Understanding the effects of sclerotia-associated fungi on the viability of Cenococcum sclerotia will be important in order to fully understand the biology and lifecycle of Cenococcum in nature. In the future, in vitro studies that combine microscopy, inoculations of specific sclerotia-associated fungi, and the use of both fresh and old sclerotia for experiments may help to elucidate the ecological interactions between Cenococcum sclerotia and other soil fungi.