Genes for cellulose-degradation and their expression conditions in Chaetomium globosum NK102

Abstract:

Abstract:［Objective］Use of renewable plant biomass is an active area in current biotechnology research． This report explores the cellulose-degradation system and the factors affecting cellulase gene expression in Chaetomium globosum NK102．［Methods］In the sequenced genome，we identified 10 cellulase genes by sequence homology alignment． We used a high-throughput sequencing technology (RNA-Seq) to monitor the differential expression of the genes under different culture conditions．［Results］We observed that cellulase activity increased with time in the fungal cultures．Accordingly，transcription of the genes encoding cellobiohydrolase，cellobiose dehydrogenase and endoglucanase (cbh1， cdh and egl1) was higher than the others． Expression of the transcriptional repressors，ACE I and CreA，decreased with the time，whereas expression of Hap2/3/5 complex was upregulated． In different carbon sources，cellulase activity and their gene transcription were repressed by glucose and were activated by cellobiose． Sorbitol had no significant effect．Interestingly，light affected positively the expression of these cellulase genes． ［Conclusion］ Differential RNA-seq analysis can make preliminary exploration on the expression regulation of cellulase genes． Expression of the genes in C．globosum was determined by different culture conditions． This study has shown a molecular system of cellulose-degradation in C．globosum and provides information for interpretation of carbohydrate metabolism．