Transcriptome analysis reveals key genes involved in the degradation of corn cobs by Auricularia heimuer

Auricularia heimuer, a prevalent white-rot fungus, is recognized for its efficient ability to degrade lignocellulose, positioning it as a promising species for the bioconversion of agricultural waste. To reduce cultivation costs and enhance the utilization of agricultural residues, this study investigates the potential of using corn cobs as a sustainable alternative to wood chips. A. heimuer was cultured on glucose, corn cobs, and wood chips to investigate its degradation mechanisms on corn cobs. Enzyme activity assays indicated a significant increase in filter paper enzyme activity when A. heimuer was grown on the corn cobs substrate. To further explore the changes in lignocellulose-degrading enzyme genes, transcriptome sequencing was performed on A. heimuer mycelia cultivated with three carbon sources. The results revealed that differentially expressed genes were significantly enriched in pathways such as starch and sucrose metabolism, pentose and glucuronate interconversions, and carbon metabolism. Transcriptome analysis indicated 50 differentially expressed lignocellulose-degrading enzyme genes, with those related to cellulose and hemicellulose degradation being significantly upregulated on the corn cobs substrate. These findings underscore the potential of A. heimuer to efficiently degrade cellulose and hemicellulose in corn cobs, supporting the use of corn cobs as a sustainable substrate in A. heimuer cultivation.