cAMP activates calcium signalling via phospholipase C to regulate cellulase production in the filamentous fungus Trichoderma reesei

Yumeng Chen; Xingjia Fan; Xinqing Zhao; Yaling Shen; Xiangyang Xu; Liujing Wei; Wei Wang; Dongzhi Wei

doi:10.1186/s13068-021-01914-0

cAMP activates calcium signalling via phospholipase C to regulate cellulase production in the filamentous fungus Trichoderma reesei

Biotechnol Biofuels. 2021 Mar 8;14(1):62. doi: 10.1186/s13068-021-01914-0.

Authors

Yumeng Chen¹, Xingjia Fan¹, Xinqing Zhao², Yaling Shen¹, Xiangyang Xu³, Liujing Wei¹, Wei Wang⁴, Dongzhi Wei¹

Affiliations

¹ State Key Lab of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, 130 Meilong Road , P.O.B. 311, Shanghai, 200237, China.
² State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
³ Zaozhuang Jie Nuo Enzyme Co. Ltd., Shandong, China.
⁴ State Key Lab of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, 130 Meilong Road , P.O.B. 311, Shanghai, 200237, China. wadexp@ecust.edu.cn.

Abstract

Background: The filamentous fungus Trichoderma reesei is one of the best producers of cellulase and has been widely studied for the production of cellulosic ethanol and bio-based products. We previously reported that Mn²⁺ and N,N-dimethylformamide (DMF) can stimulate cellulase overexpression via Ca²⁺ bursts and calcium signalling in T. reesei under cellulase-inducing conditions. To further understand the regulatory networks involved in cellulase overexpression in T. reesei, we characterised the Mn²⁺/DMF-induced calcium signalling pathway involved in the stimulation of cellulase overexpression.

Results: We found that Mn²⁺/DMF stimulation significantly increased the intracellular levels of cAMP in an adenylate cyclase (ACY1)-dependent manner. Deletion of acy1 confirmed that cAMP is crucial for the Mn²⁺/DMF-stimulated cellulase overexpression in T. reesei. We further revealed that cAMP elevation induces a cytosolic Ca²⁺ burst, thereby initiating the Ca²⁺ signal transduction pathway in T. reesei, and that cAMP signalling causes the Ca²⁺ signalling pathway to regulate cellulase production in T. reesei. Furthermore, using a phospholipase C encoding gene plc-e deletion strain, we showed that the plc-e gene is vital for cellulase overexpression in response to stimulation by both Mn²⁺ and DMF, and that cAMP induces a Ca²⁺ burst through PLC-E.

Conclusions: The findings of this study reveal the presence of a signal transduction pathway in which Mn²⁺/DMF stimulation produces cAMP. Increase in the levels of cAMP activates the calcium signalling pathway via phospholipase C to regulate cellulase overexpression under cellulase-inducing conditions. These findings provide insights into the molecular mechanism of the cAMP-PLC-calcium signalling pathway underlying cellulase expression in T. reesei and highlight the potential applications of signal transduction in the regulation of gene expression in fungi.

Keywords: Adenylate cyclase; Calcium signalling; Cellulase; Cyclic AMP; Filamentous fungi; Mn2+/DMF stimulation; Trichoderma reesei.

Abstract

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