Fei Chen1,2, Xiu-Zhen Chen3, Xiao-Yun Su1, Li-Na Qin1, Zhen-Bang Huang1,2, Yong Tao1, Zhi-Yang Dong4. 1. State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, NO. 1 West Beichen Road, Chaoyang District, Beijing, 100101, People's Republic of China. 2. University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China. 3. State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, NO. 1 West Beichen Road, Chaoyang District, Beijing, 100101, People's Republic of China. chenxiuzhen@im.ac.cn. 4. State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, NO. 1 West Beichen Road, Chaoyang District, Beijing, 100101, People's Republic of China. dongzy@mail.im.ac.cn.
Abstract
OBJECTIVES: Eukaryotic mitogen-activated protein kinases (MAPKs) play crucial roles in transducing environmental and developmental signals inside the cell and regulating gene expression, however, the roles of MAPKs remain largely unknown in Trichoderma reesei. RESULTS: T. reesei ime2 (TrIme2) encodes an Ime2-like MAPK in T. reesei. The deletion of the TrIme2 gene led to 90% increase in cellulase activity against filter paper during earlier period time of cellulase induction as well as the extracellular protein production. Compared to the parent strain, the transcriptional levels of the three major cellulase genes cbh1,cbh2, egl1 were increased by about 9 times, 4 times, 2 times, respectively, at 8 h after cellulase induction in the ΔTrIme2 mutant. In addition, the disruption of TrIme2 caused over 50% reduction of the transcript levels of cellulase transcriptional regulators cre1 and xyr1. CONCLUSION: TrIme2 functions in regulation of the expression of cellulase gene in T.reesei, and is a good candidate for genetically engineering of T. reesei for higher cellulase production.
OBJECTIVES: Eukaryotic mitogen-activated protein kinases (MAPKs) play crucial roles in transducing environmental and developmental signals inside the cell and regulating gene expression, however, the roles of MAPKs remain largely unknown in Trichoderma reesei. RESULTS:T. reesei ime2 (TrIme2) encodes an Ime2-like MAPK in T. reesei. The deletion of the TrIme2 gene led to 90% increase in cellulase activity against filter paper during earlier period time of cellulase induction as well as the extracellular protein production. Compared to the parent strain, the transcriptional levels of the three major cellulase genes cbh1,cbh2, egl1 were increased by about 9 times, 4 times, 2 times, respectively, at 8 h after cellulase induction in the ΔTrIme2 mutant. In addition, the disruption of TrIme2 caused over 50% reduction of the transcript levels of cellulase transcriptional regulators cre1 and xyr1. CONCLUSION:TrIme2 functions in regulation of the expression of cellulase gene in T.reesei, and is a good candidate for genetically engineering of T. reesei for higher cellulase production.