The CBS/H 2 S signalling pathway regulated by the carbon repressor CreA promotes cellulose utilization in Ganoderma lucidum.

Cellulose is an important abundant renewable resource on Earth, and the microbial cellulose utilization mechanism has attracted extensive attention. Recently, some signalling molecules have been found to regulate cellulose utilization and the discovery of underlying signals has recently attracted extensive attention. In this paper, we found that the hydrogen sulfide (H2 S) concentration under cellulose culture condition increased to approximately 2.3-fold compared with that under glucose culture condition in Ganoderma lucidum. Further evidence shown that cellulase activities of G. lucidum were improved by 18.2-27.6% through increasing H2 S concentration. Then, we observed that the carbon repressor CreA inhibited H2 S biosynthesis in G. lucidum by binding to the promoter of cbs, a key gene for H2 S biosynthesis, at "CTGGGG". In our study, we reported for the first time that H2 S increased the cellulose utilization in G. lucidum, and analyzed the mechanism of H2 S biosynthesis induced by cellulose. This study not only enriches the understanding of the microbial cellulose utilization mechanism but also provides a reference for the analysis of the physiological function of H2 S signals.