Time-Dependent Profiles of Transcripts Encoding Lignocellulose-Modifying Enzymes of the White Rot Fungus Phanerochaete carnosa Grown on Multiple Wood Substrates

ABSTRACTThe abundances of nine transcripts predicted to encode lignocellulose-modifying enzymes were measured over the course ofPhanerochaete carnosacultivation on four wood species. Profiles were consistent with sequential decay; transcripts encoding lignin-degrading peroxidases featured a significant substrate-dependent response. The chitin synthase gene was identified as the optimal internal reference gene for transcript quantification.

Transcriptomic Responses of the Softwood-Degrading White-Rot Fungus Phanerochaete carnosa during Growth on Coniferous and Deciduous Wood

ABSTRACTTo identify enzymes that could be developed to reduce the recalcitrance of softwood resources, the transcriptomes of the softwood-degrading white-rot fungusPhanerochaete carnosawere evaluated after growth on lodgepole pine, white spruce, balsam fir, and sugar maple and compared to the transcriptome ofP. carnosaafter growth on liquid nutrient medium. One hundred fifty-two million paired-end reads were obtained, and 63% of these reads were mapped to 10,257 gene models fromP. carnosa.Five-hundred thirty-three of these genes had transcripts that were at least four times more abundant during growth on at least one wood medium than on nutrient medium. The 30 transcripts that were on average over 100 times more abundant during growth on wood than on nutrient medium included 6 manganese peroxidases, 5 cellulases, 2 hemicellulases, a lignin peroxidase, glyoxal oxidase, and a P450 monooxygenase. Notably, among the genes encoding putative cellulases, one encoding a glycosyl hydrolase family 61 protein had the highest relative transcript abundance during growth on wood. Overall, transcripts predicted to encode lignin-degrading activities were more abundant than those predicted to encode carbohydrate-active enzymes. Transcripts predicted to encode three MnPs represented the most highly abundant transcripts in wood-grown cultivations compared to nutrient medium cultivations. Gene set enrichment analyses did not distinguish transcriptomes resulting from softwood and hardwood cultivations, suggesting that similar sets of enzyme activities are elicited byP. carnosagrown on different wood substrates, albeit to different expression levels.