Open Access Highly Accessed Research article

Post-genomic analyses of fungal lignocellulosic biomass degradation reveal the unexpected potential of the plant pathogen Ustilago maydis

Marie Couturier1, David Navarro12, Caroline Olivé1, Didier Chevret3, Mireille Haon12, Anne Favel124, Laurence Lesage-Meessen12, Bernard Henrissat5, Pedro M Coutinho45 and Jean-Guy Berrin1*

Author Affiliations

1 INRA, UMR1163 BCF, 13288 Marseille, France

2 INRA, UMR1163 CIRM-CF, 13288 Marseille, France

3 INRA, UMR1319 Micalis, PAPPSO, 78352 Jouy-en-Josas, France

4 Aix-Marseille Universités, 13288 Marseille, France

5 CNRS, UMR6098 AFMB, 13288 Marseille, France

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BMC Genomics 2012, 13:57  doi:10.1186/1471-2164-13-57

Published: 2 February 2012

Abstract

Background

Filamentous fungi are potent biomass degraders due to their ability to thrive in ligno(hemi)cellulose-rich environments. During the last decade, fungal genome sequencing initiatives have yielded abundant information on the genes that are putatively involved in lignocellulose degradation. At present, additional experimental studies are essential to provide insights into the fungal secreted enzymatic pools involved in lignocellulose degradation.

Results

In this study, we performed a wide analysis of 20 filamentous fungi for which genomic data are available to investigate their biomass-hydrolysis potential. A comparison of fungal genomes and secretomes using enzyme activity profiling revealed discrepancies in carbohydrate active enzymes (CAZymes) sets dedicated to plant cell wall. Investigation of the contribution made by each secretome to the saccharification of wheat straw demonstrated that most of them individually supplemented the industrial Trichoderma reesei CL847 enzymatic cocktail. Unexpectedly, the most striking effect was obtained with the phytopathogen Ustilago maydis that improved the release of total sugars by 57% and of glucose by 22%. Proteomic analyses of the best-performing secretomes indicated a specific enzymatic mechanism of U. maydis that is likely to involve oxido-reductases and hemicellulases.

Conclusion

This study provides insight into the lignocellulose-degradation mechanisms by filamentous fungi and allows for the identification of a number of enzymes that are potentially useful to further improve the industrial lignocellulose bioconversion process.

Keywords:
Filamentous fungi; genomes; lignocellulose; enzymatic hydrolysis; cellulases; oxido-reductases; glycosyl hydrolases; Ustilago maydis; mass spectrometry