Transmembrane transport process and endoplasmic reticulum function facilitate the role of gene cel1b in cellulase production of Trichoderma reesei

Microbial Cell Factories

Chengcheng Li¹  Xiaotong Shi¹  Bing-Zhi Li²  Fu-Gen Wu³  Zuhong Lu³  Xin Hu³  Haiyan Wang³  Funing Zhang³  Ai-Ping Pang³  Yongsheng Luo³  Samran Durrani³  Fengming Lin³  Yichen Gao³ 

[1] International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University;Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University;State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University;

关键词: Filamentous fungus;    β-glucosidase;    cel1b;    Sugar transporters;    Protein export;    Protein processing;   

DOI  :  10.1186/s12934-022-01809-1

来源: DOAJ

【 摘 要 】

Abstract Background A total of 11 β-glucosidases are predicted in the genome of Trichoderma reesei, which are of great importance for regulating cellulase biosynthesis. Nevertheless, the relevant function and regulation mechanism of each β-glucosidase remained unknown. Results We evidenced that overexpression of cel1b dramatically decreased cellulase synthesis in T. reesei RUT-C30 both at the protein level and the mRNA level. In contrast, the deletion of cel1b did not noticeably affect cellulase production. Protein CEL1B was identified to be intracellular, being located in vacuole and cell membrane. The overexpression of cel1b reduced the intracellular pNPGase activity and intracellular/extracellular glucose concentration without inducing carbon catabolite repression. On the other hand, RNA-sequencing analysis showed the transmembrane transport process and endoplasmic reticulum function were affected noticeably by overexpressing cel1b. In particular, some important sugar transporters were notably downregulated, leading to a compromised cellular uptake of sugars including glucose and cellobiose. Conclusions Our data suggests that the cellulase inhibition by cel1b overexpression was not due to the β-glucosidase activity, but probably the dysfunction of the cellular transport process (particularly sugar transport) and endoplasmic reticulum (ER). These findings advance the knowledge of regulation mechanism of cellulase synthesis in filamentous fungi, which is the basis for rationally engineering T. reesei strains to improve cellulase production in industry.

【 授权许可】

Unknown