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United States Department of Agriculture

Agricultural Research Service

Research Project: CONTROL OF FUMONISIN MYCOTOXIN CONTAMINATION IN MAIZE THROUGH ELUCIDATION OF GENETIC AND ENVIRONMENTAL FACTORS ... METABOLISM IN FUSARIUM

Location: Bacterial Foodborne Pathogens & Mycology Research Unit

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

Authors
item Riley, Robert -
item Salamov, Asaf -
item Brown, Daren
item Nagy, Laszlo -
item Floudas, Dimitris -
item Held, Benjamin -
item Levasseur, Anthony -
item Lombard, Vincent -
item Morin, Emmanuellle -
item Otillar, Robert -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 12, 2014
Publication Date: June 12, 2014
Citation: Riley, R., Salamov, A., Brown, D.W., Nagy, L.G., Floudas, D., Held, B., Levasseur, A., Lombard, V., Morin, E., Otillar, R. 2014. Extensive sampling of basidiomycete genomes demonstrates inadequacy of the white rot/brown rot paradigm for wood decay fungi. Meeting Abstract.

Technical Abstract: 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.

Last Modified: 7/31/2014
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