Dr. David Hibbett
Warren Litsky Endowed Chair in Biology
Department of Biology
Biochemistry and Molecular Biology Program
Department of Environmental Science
"Getting to the Roots of Rot: Phylogenomics of Wood-Decaying Mushrooms"
Mark your calendar for the next NEBC Meeting with Dr. David Hibbett on May 1, 2015, 6:45 PM at Garden in the Woods, Framingham, MA.
This fungus is able to degrade all components of plant cell walls, including lignin, thanks to the presence of PODs and diverse enzymes that attack crystalline cellulose and other carbohydrates.
Abstract: The evolution of lignin biosynthesis was a great innovation that enabled tracheophytes to radiate on the land and create forested ecosystems. The evolution of high redox potential class II peroxidases (PODs) was a complementary innovation that enabled certain "white rot" fungi to gain access to the carbohydrates embedded in heavily lignified plant cell walls. Along with colleagues from the Department of Energy Joint Genome Institute, we have been studying the origins of PODs and other enzymes involved in decay of plant cell walls using fungal genomes. Molecular clock analyses combined with gene tree/species tree reconstruction suggest that the origin of PODs and white rot roughly coincided with the steep decline in the rate of organic carbon sequestration around the end of the Permo-Carboniferous. This result has been over-interpreted as meaning that the evolution of white rot Agaricomycetes "caused the end of the Carboniferous". However, other factors may also have contributed to the reduction in coal deposition, including physio-geographic shifts (contraction of extensive coastal swamp forests) and changes in plant investment in lignin (associated with decline of arboreal lycophytes and sphenophytes and expansions of seed plants). We are continuing our genomic survey to include diverse lineages of Agaricomycetes, including mycorrhizal species. To assess the factors that caused organic carbon sequestration to decline at the end of the Permo-Carboniferous, it will be necessary to perform studies in paleoecosytem modeling that consider the relative impact of the evolution of PODs, paleogeographic shifts and changes in plant cell wall chemistry.
Meeting Celebrating Students
In conjunction with NEBC's 1100th meeting, previous Graduate Student Research Award Winners were asked to share information about themselves and their publications that resulted from work supported by NEBC's research award. Where are they now?