Abstract Detail

Lignocellulose Deconstruction by Fungi

Riley, Robert [1], Salamov, Asaf [2], Brown, Daren W [3], Nagy, Laszlo [4], Floudas, Dimitrios [4], Held, Benjamin [5], Levasseur, Anthony [6], Lombard, Vincent [6], Morin, Emmanuelle [7], Otillar, Robert [2], Lindquist, Erika [2], Sun, Hui [2], LaButti, Kurt [2], Schmutz, Jeremy [2], Jabbour, Dina [8], Luo, Hong [9], Baker, Scott  [10], Pisabarro, Antonio [11], Walton, Jonathan [12], Blanchette, Robert [5], Henrissat, Bernard [13], Martin, Francis [7], Cullen, Daniel [14], Hibbett, David S. [4], Grigoriev, Igor [2].

Extensive sampling of basidiomycete genomes demonstrates inadequacy of the white rot/brown rot paradigm for wood decay fungi.

Basidiomycota (basidiomycetes) make up 32% of the described fungi and include most wood decaying species, as well as pathogens and mutualistic symbionts. Wood-decaying basidiomycetes have typically been classified as either white rot or brown rot, based on the ability (in white rot only) to degrade lignin along with cellulose and hemicellulose. Prior genomic comparisons suggested that the two decay modes can be distinguished based on the presence or absence of ligninolytic class II peroxidases (PODs), as well as the abundance of enzymes acting directly on crystalline cellulose (reduced in brown rot). To assess the generality of the white rot/brown rot classification paradigm we compared the genomes of 33 basidiomycetes, including four newly sequenced wood decayers, and performed phylogenetically-informed Principal Components Analysis (PCA) of a broad range of gene families encoding plant biomass-degrading enzymes. The newly sequenced Botryobasidium botryosum and Jaapia argillacea genomes lack PODs, but possess diverse enzymes acting on crystalline cellulose, and they group close to the model white rot species Phanerochaete chrysosporium in the PCA. Furthermore, laboratory assays showed that both B. botryosum and J. argillacea can degrade all polymeric components of woody plant cell walls, a characteristic of white rot. We also found expansions in reducing polyketide synthase genes specific to the brown rot fungi. Our results suggest a continuum rather than a dichotomy between the white rot and brown rot modes of wood decay. A more nuanced categorization of rot types is needed, based on an improved understanding of the genomics and biochemistry of wood decay.

1 - US Department of Energy Joint Genome Institute, Fungal Program, 2800 Mitchell Drive, Walnut Creek, CA, 94598, USA
2 - US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA, 94598, USA
3 - USDA, Peoria, IL, 61604, USA
4 - Clark University, Biology Department, 950 Main street, Worcester, MA, 01610, USA
5 - University of Minnesota, 1991 Upper Buford Circle, St. Paul, MN, 55108, USA
6 - Institut National de la Recherche Agronomique, Marseille, France
7 - Institut National de la Recherche Agronomique, Champenoux, France
8 - DOE Great Lakes Bioenergy Research Center, E. Lansing, MI, 48824, USA
9 - Michigan State University, Plant Research Lab, 612 Wilson Road Room 210, E. Lansing, MI, 48824, USA
10 - Pacific Northwest National Laboratory, Richland, WA, 99352, USA
11 - Univ. Pública de Navarra, Depto. de Producción Agraria, Pamplona, Spain
12 - Michigan State University, Department of Energy Great Lakes Bioenergy Research Center, 210 Plant Biology Building, E. Lansing, 48824, USA
13 - Centre National de la Recherche Scientifique, Marseille, France
14 - Forest Products Laboratory, One Gifford Pinchot Dr, Madison, WI, 53726, USA

Keywords:
lignocellulose
Basidiomycete
wood decay.

Presentation Type: Symposium or Colloquium Presentation
Session: SY9
Location: Room 104 AB/Kellogg Hotel and Conference Center
Date: Wednesday, June 11th, 2014
Time: 2:00 PM
Number: SY9003
Abstract ID:191
Candidate for Awards:None