A novel transcriptional regulator RXE1 modulates the essential transactivator XYR1 and cellulase gene expression in Trichoderma reesei

• Published in: Applied microbiology and biotechnology Vol. 103; no. 11; pp. 4511 - 4523
• Main Authors: Wang, Lei, Lv, Xinxing, Cao, Yanli, Zheng, Fanglin, Meng, Xiangfeng, Shen, Yu, Chen, Guanjun, Liu, Weifeng, Zhang, Weixin
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2019; Springer; Springer Nature B.V
• Subjects: Analysis; Applied Microbial and Cell Physiology; Biodegradation; Biomedical and Life Sciences; Biotechnology; Cell walls; Cellulase; Conidia; Fungi; Gene expression; Gene regulation; Genetic aspects; Genetic regulation; Genetic transcription; Homology; Innovations; Life Sciences; Microbial Genetics and Genomics; Microbiology; Molds (Fungi); RNA-mediated interference; Trichoderma reesei; Yeast; Yeasts; Transcriptional regulator; XYR1; RXE1; Cellulase; Trichoderma reesei
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-019-09739-6

XYR1 is the key transcription activator for cellulase gene expression in the model filamentous fungus Trichoderma reesei , which is widely applied in the industry due to its excellent capability of secreting a large quantity of cellulases. Despite the essential role of XYR1, the regulation of its expression in T. reesei cellulolytic response is poorly understood. In this study, we identified a transcription factor RXE1 exhibiting strong binding activity to the xyr1 promoter using yeast one-hybrid screen. RXE1 homologs exist in quite a few filamentous fungi but none of them have been assessed regarding their functional involvement in plant cell wall degradation. Knockdown of rxe1 in T. reesei using a copper-mediated RNAi system not only abrogated conidiation, but also remarkably compromised xyr1 and cellulase gene expression. The defective cellulase but not conidia production in the rxe1 -knockdown strain was fully rescued by the constitutive expression of XYR1. Our study thus identified a novel transcriptional regulator controlling xyr1 and cellulase gene expression, which will contribute to elaborating the intricate network of cellulase gene regulation in T. reesei .