The soils of the boreal forests in the northern latitudes are estimated to store more than three times the amount of carbon contained in the atmosphere or in plant life on land. Recent studies suggest the relationship between fungi on the forest floor, plants and the microbial communities at the plant roots (or rhizosphere) plays a larger role than had been known about the process by which the stored carbon is broken down and accessed as nutrients.
Paxillus involutus, also known as the common or brown rollrim
To learn more about this process, the common rollrim (Paxillus involutus) mushroom was selected for the DOE JGI’s 2008 Community Sequencing Program. In particular, the transcriptomes from the fungus were sequenced using the Roche 454 platform to learn when and where each gene is turned on or off.
The findings reported in an article published March 30, 2012 in Environmental Microbiology suggest that while P. involutus can break down the carbon trapped in the soil in a manner similar to the approach used by brown rot fungi, it cannot release the carbon for use, leaving that capability to the soil microbes with which it has formed a mutually-dependent relationship.
“The combined metabolic activity of symbiotic fungi and saprophytic microbes may have a significant impact on the turnover of carbon and nutrients in forest soils,” wrote the research team which included DOE JGI Fungal Program head Igor Grigoriev. “Moreover, being supplied by energy from the plant, this pathway could operate at deeper soil horizons that are energetically unavailable for traditional saprophytes.”