Transcriptomic responses of Phanerochaete chrysosporium to oak acetonic extracts: focus on a new glutathione transferase

• Published in: Applied and Environmental Microbiology Vol. 80; no. 20; pp. 6316 - 6327
• Main Authors: Thuillier, Anne, Chibani, Kamel, Belli, Gemma, Herrero, Enrique, Dumarçay, Stéphane, Gérardin, Philippe, Kohler, Annegret, Deroy, Aurélie, Dhalleine, Tiphaine, Bchini, Raphael, Jacquot, Jean-Pierre, Gelhaye, Eric, Morel-Rouhier, Mélanie
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01.10.2014
• Subjects: Acetone - chemistry; Antioxidants; Basidiomycetes; Environmental Microbiology; Evolution, Molecular; Fungi; Gene Expression Regulation, Fungal; Genes; Glutathione Transferase - genetics; Glutathione Transferase - metabolism; Inactivation, Metabolic; Isoenzymes; Life Sciences; Lignin - metabolism; Lipid Peroxidation; Molecular weight; Oxidative Stress - drug effects; Peroxides - chemistry; Peroxides - metabolism; Phanerochaete - drug effects; Phanerochaete - genetics; Phanerochaete - metabolism; Phanerochaete chrysosporium; Plant Extracts - chemistry; Plant Extracts - pharmacology; Quercus - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Substrates; Wood - microbiology; Yeast
• ISSN: 0099-2240; 1098-5336; 1098-6596
• DOI: 10.1128/aem.02103-14

The first steps of wood degradation by fungi lead to the release of toxic compounds known as extractives. To better understand how lignolytic fungi cope with the toxicity of these molecules, a transcriptomic analysis of Phanerochaete chrysosporium genes was performed in the presence of oak acetonic extracts. It reveals that in complement to the extracellular machinery of degradation, intracellular antioxidant and detoxification systems contribute to the lignolytic capabilities of fungi, presumably by preventing cellular damages and maintaining fungal health. Focusing on these systems, a glutathione transferase (P. chrysosporium GTT2.1 [PcGTT2.1]) has been selected for functional characterization. This enzyme, not characterized so far in basidiomycetes, has been classified first as a GTT2 compared to the Saccharomyces cerevisiae isoform. However, a deeper analysis shows that the GTT2.1 isoform has evolved functionally to reduce lipid peroxidation by recognizing high-molecular-weight peroxides as substrates. Moreover, the GTT2.1 gene has been lost in some non-wood-decay fungi. This example suggests that the intracellular detoxification system evolved concomitantly with the extracellular ligninolytic machinery in relation to the capacity of fungi to degrade wood.