title: A novel bZIP transcription factor ClrC positively regulates multiple stress responses, conidiation and cellulase expression in Penicillium oxalicum.
abstract: Cellulase production in filamentous fungi is largely regulated at the transcriptional level, and several transcription factors have been reported to be involved in this process. In this study, we identified ClrC, a novel transcription factor in cellulase production in Penicillium oxalicum. ClrC and its orthologs have a highly conserved basic leucine zipper (bZIP) DNA binding domain, and their biological functions have not been explored. Deletion of clrC resulted in pleiotropic effects, including altered growth, reduced conidiation and increased sensitivity to oxidative and cell wall stresses. In particular, the clrC deletion mutant ΔclrC showed 46.1% ± 8.1% and 58.0% ± 8.7% decreases in production of filter paper enzyme and xylanase activities in cellulose medium, respectively. In contrast, 57.4% ± 10.0% and 70.9% ± 19.4% increased production of filter paper enzyme, and xylanase was observed in the clrC overexpressing strain, respectively. The transcription levels of major cellulase genes, as well as two cellulase transcriptional activator genes, clrB and xlnR, were significantly downregulated in ΔclrC, but substantially upregulated in clrC overexpressing strains. Furthermore, we observed that the absence of ClrC reduced full induction of cellulase expression even in the clrB overexpressing strain. These results indicated that ClrC is a novel and efficient engineering target for improving cellulolytic enzyme production in filamentous fungi.
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, Shandong 250100, PR China.
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Lei
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, Shandong 250100, PR China.
authors.forename: Guodong
authors.initials: G
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, Shandong 250100, PR China.
authors.forename: Guangshan
authors.initials: G
authors.lastname: Yao
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, Shandong 250100, PR China.
authors.forename: Zhonghai
authors.initials: Z
authors.lastname: Li
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, Shandong 250100, PR China; National Glycoengineering Research Center, Shandong University, Shan Da Nan Road 27, Jinan, Shandong 250100, PR China.
authors.forename: Yuqi
authors.initials: Y
authors.lastname: Qin
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, Shandong 250100, PR China; National Glycoengineering Research Center, Shandong University, Shan Da Nan Road 27, Jinan, Shandong 250100, PR China. Electronic address: quyinbo@sdu.edu.cn.
authors.forename: Yinbo
authors.initials: Y
authors.lastname: Qu
mesh_terms: D002480:Cellulase / Q000378:metabolism*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D016350:Leucine Zippers; D010407:Penicillium / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D013172:Spores, Fungal / Q000254:growth & development*; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D014157:Transcription Factors; D002480:Cellulase
keywords: Cellulolytic enzyme; Penicillium oxalicum; Transcription factor; bZIP domain; clrC