OVERVIEW
Wood, the tough, durable material that is used to make everything from houses to chopsticks, is a major reservoir of carbon in the global ecosystem. The task of recycling this carbon falls largely to fungi, especially Agaricomycetes, which includes polypores, gilled mushrooms, puffballs, and coral fungi. Wood decaying Agaricomycetes tend to occur on specific tree species and to specialize on different classes of wood (e.g., live vs. dead trees, massive logs vs. twigs, aerial limbs vs. roots and stumps, and so on). In recent years, through advances in genomics and biochemistry, we have learned a great deal about how Agaricomycetes decay wood. We have cataloged diverse enzymes that break down the components of wood, and identified their genes. However, we still know very little about why wood decaying Agaricomycetes occur on specific substrates. This project leveraged recent advances in fungal genomics and evolutionary biology to address the causes of substrate-specificity in wood decaying Agaricomycetes.
INTELLECTUAL MERIT
We grew selected species of Agaricomycetes on different types of wood, and studied gene expression. Our main goal was to determine if wood decaying Agaricomycetes can adjust the suite of enzymes that they produce in response to different substrates. We also used mass spectrometry to study changes in wood chemistry during decay, and we studied the evolution of wood decay and other nutritional modes in Agaricomycetes. This was a collaborative project involving four laboratories at Clark University, the University of Toronto, University of Minnesota, and the University of California Berkeley. We also collaborated with colleagues at the USDA Forest Products laboratory in Madison, Wisconsin.
So far, we have published nine articles reporting the results of this project (as of this writing, three more are in review). We conducted two major studies, one in the "red belt polypore" Fomitopis pinicola, and another that compared five different species. In both, we found that wood-decaying Agaricomycetes are able to modify gene expression according to substrate type. We also performed several evolutionary analyses that provided a broad view of the origins of decay mechanisms, and how those mechanisms have changed over geologic time. 
BROADER IMPACTS
This project served to develop and strengthen professional networks involving four universities (three public, one private) and a federal research laboratory, in two countries. Trainees who were supported included postdoctoral fellows, graduate students, and undergraduates.
The major outreach component of this project involved creation of exhibits on fungal biology (emphasizing decay) and evolution at the EcoTarium in Worcester, Massachusetts opened to the public in September, 2018, and remain on display (see https://hibbettlablog.wordpress.com/2018/09/18/fungi-at-the-ecotarium/). In addition, we participated in outreach activities including mushroom forays for the public, and presentations to amateur mycology clubs.
Wood decay has profound impacts not only on the functioning of natural ecosystems, but also on human affairs. Decay of wood in service (e.g., in buildings) is costly and damaging. At the same time, the enzymes produced by wood decay fungi have potential applications in industrial bioconversions, including biofuel production and bioremediation. While this project was not directly motivated by applied goals, the basic research that we performed provides resources for scientists who seek to harness the enzymatic machinery of wood decay fungi for the benefit of humanity.

Last Modified: 06/18/2020
Modified by: Igor Grigoriev