A novel bZIP transcription factor ClrC positively regulates multiple stress responses, conidiation and cellulase expression in Penicillium oxalicum

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• 作者：Yunfeng Lei^a ; Guodong Liu^a ; Guangshan Yao^a ; Zhonghai Li^a ; Yuqi Qin^a ; ^b ; Yinbo Qu^a ; ^b ; ^{quyinbo@sdu.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Penicillium oxalicum ; clrC ; bZIP domain ; Transcription factor ; Cellulolytic enzyme
• 刊名：Research in Microbiology
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：167
• 期：5
• 页码：424-435
• 全文大小：2111 K

文摘

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.