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A Special Phenotype of Aconidial Aspergillus niger SH2 and Its Mechanism of Formation via CRISPRi. J Fungi (Basel) 2022; 8:jof8070679. [PMID: 35887436 PMCID: PMC9319794 DOI: 10.3390/jof8070679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/14/2022] [Accepted: 06/16/2022] [Indexed: 11/17/2022] Open
Abstract
The complex morphological structure of Aspergillus niger influences its production of proteins, metabolites, etc., making the genetic manipulation and clonal purification of this species increasingly difficult, especially in aconidial Aspergillus niger. In this study, we found that N-acetyl-D-glucosamine (GlcNAc) could induce the formation of spore-like propagules in the aconidial Aspergillus niger SH2 strain. The spore-like propagules possessed life activities such as drug resistance, genetic transformation, and germination. Transcriptomic analysis indicated that the spore-like propagules were resting conidia entering dormancy and becoming more tolerant to environmental stresses. The Dac1 gene and the metabolic pathway of GlcNAc converted to glycolysis are related to the formation of the spore-like propagules, as evidenced by the CRISPRi system, qPCR, and semi-quantitative RT-PCR. Moreover, a method based on the CRISPR-Cas9 tool to rapidly recycle screening tags and recover genes was suitable for Aspergillus niger SH2. To sum up, this suggests that the spore-like propagules are resting conidia and the mechanism of their formation is the metabolic pathway of GlcNAc converted to glycolysis, particularly the Dac1 gene. This study can improve our understanding of the critical factors involved in mechanisms of phenotypic change and provides a good model for researching phenotypic change in filamentous fungi.
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Qiu L, Song JZ, Li J, Zhang TS, Li Z, Hu SJ, Liu JH, Dong JC, Cheng W, Wang JJ. The transcription factor Ron1 is required for chitin metabolism, asexual development and pathogenicity in Beauveria bassiana, an entomopathogenic fungus. Int J Biol Macromol 2022; 206:875-885. [PMID: 35278517 DOI: 10.1016/j.ijbiomac.2022.03.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 03/06/2022] [Accepted: 03/07/2022] [Indexed: 11/05/2022]
Abstract
Ndt80-like transcription factor Ron1 is best known for its essential role in the regulation of N-acetylglucosamine (GlcNAc) catabolism. Ron1 was again found to be essential for sensing GlcNAc in Beauveria bassiana. Importantly, our study revealed that Ron1 is involved in the metabolic processes of chitin and asexual development. To further investigate the novel functions of Ron1 in B. bassiana, extracellular chitinase activity in the ΔRon1 mutant was found to decrease by 84.73% compared with wild type. The deletion of Ron1 made it difficult for the fungus to accumulate intracellular GlcNAc. Furthermore, transcriptomic analysis revealed that Ron1 exerted a significant effect on global transcription and positively regulated genes encoding chitin metabolism in respond to chitin nutrition. Yeast one-hybrid assay confirmed that Ron1 could bind to specific cis-acting elements in the promoters of chitinase and hexokinase. In addition, ΔRon1 displayed an impaired chitin component of the cell wall, with a chitin synthetase (ChsVII) predicted to function downstream of Ron1. Finally, the virulence of ΔRon1 mutant was significantly reduced in the Galleria mellonella insect model through cuticle infection or cuticle bypassing infection. These data functionally characterize Ron1 in B. bassiana and expand our understanding of how the transcription factor Ron1 works in pathogens.
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Affiliation(s)
- Lei Qiu
- School of Biological Science and Technology, University of Jinan, Jinan, China; State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Ji-Zheng Song
- School of Biological Science and Technology, University of Jinan, Jinan, China; State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China; Maize Research Institute, Shandong Academy of Agricultural Sciences, Jinan, China
| | - Juan Li
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Tong-Sheng Zhang
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Ze Li
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Shun-Juan Hu
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Jia-Hua Liu
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Jing-Chong Dong
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Wen Cheng
- Maize Research Institute, Shandong Academy of Agricultural Sciences, Jinan, China
| | - Juan-Juan Wang
- School of Biological Science and Technology, University of Jinan, Jinan, China.
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