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Liu S, Lu X, Dai M, Zhang S. Transcription factor CreA is involved in the inverse regulation of biofilm formation and asexual development through distinct pathways in Aspergillus fumigatus. Mol Microbiol 2023; 120:830-844. [PMID: 37800624 DOI: 10.1111/mmi.15179] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 08/17/2023] [Accepted: 09/21/2023] [Indexed: 10/07/2023]
Abstract
The exopolysaccharide galactosaminogalactan (GAG) contributes to biofilm formation and virulence in the pathogenic fungus Aspergillus fumigatus. Increasing evidence indicates that GAG production is inversely linked with asexual development. However, the mechanisms underlying this regulatory relationship are unclear. In this study, we found that the dysfunction of CreA, a conserved transcription factor involved in carbon catabolite repression in many fungal species, causes abnormal asexual development (conidiation) under liquid-submerged culture conditions specifically in the presence of glucose. The loss of creA decreased GAG production independent of carbon sources. Furthermore, CreA contributed to asexual development and GAG production via distinct pathways. CreA promoted A. fumigatus GAG production by positively regulating GAG biosynthetic genes (uge3 and agd3). CreA suppressed asexual development in glucose liquid-submerged culture conditions via central conidiation genes (brlA, abaA, and wetA) and their upstream activators (flbC and flbD). Restoration of brlA expression to the wild-type level by flbC or flbD deletion abolished the abnormal submerged conidiation in the creA null mutant but did not restore GAG production. The C-terminal region of CreA was crucial for the suppression of asexual development, and the repressive domain contributed to GAG production. Overall, CreA is involved in GAG production and asexual development in an inverse manner.
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Affiliation(s)
- Shuai Liu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xiaoyan Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Mengyao Dai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Shizhu Zhang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
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Xie X, Wang Y, Jin S, He L, Jia Z, Huang B. MrCreC, a carbon catabolite repression gene, is required for the growth, conidiation, stress tolerance and virulence of Metarhizium robertsii. J Invertebr Pathol 2023; 201:108009. [PMID: 37863281 DOI: 10.1016/j.jip.2023.108009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 10/07/2023] [Accepted: 10/17/2023] [Indexed: 10/22/2023]
Abstract
As a key component of carbon source metabolism in fungi, CreC WD40 repeat protein is regulated by carbon catabolite repression (CCR). However, the understanding of the functions of CreC in entomopathogenic fungi is currently limited. Here, CreC in Metarhizium robertsii (MrCreC) was identified, and its roles in fungal development, conidiation, environmental stress response, and insecticidal virulence were explored. MrCreC is localized to cytoplasm, and MrCreC deletion affects fungal growth on various nutrients. Compared to the wild type, the sporulation of ΔMrCreC strain was significantly decreased by 60.3%. Further qPCR analysis found that deletion of MrCreC resulted in repression of sporulation-related genes such as AbaA, FlbA, Flbc, MedA, FlbD, FluG, and wetA. In addition, MrCreC loss did not alter heat stress tolerance but resulted in enhanced tolerance to UV-B. Interestingly, bioassays showed that the virulence following exposures to topical applications or injection of conidial suspensions of both infection and injection was impaired compared with that of the wild type. Further analysis showed that the adhesion and cuticle penetration genes in ΔMrCreC was down-regulated during infection, and the appressorial formation rate was significantly reduced. A deletion of MrCreC significantly also reduced immune escape and nutrient utilization genes in insect hemocoel. In conclusion, MrCreC is involved in the growth, development and virulence of M. robertsii. These findings advance our understanding of the function of CCR pathway-related genes.
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Affiliation(s)
- Xiangyun Xie
- College of Life Sciences, Liaocheng University, Liaocheng 252059, China
| | - Yulong Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei 230036, China
| | - Shaoxia Jin
- Taiyuan City Road Green Maintenance Center, Taiyuan 030000, China
| | - Lili He
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei 230036, China
| | - Zefeng Jia
- College of Life Sciences, Liaocheng University, Liaocheng 252059, China.
| | - Bo Huang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei 230036, China.
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Luo Z, Chen Q, Su Y, Hu S, Keyhani NO, Wang J, Zhu C, Zhou T, Pan Y, Bidochka MJ, Zhang Y. The AreA Nitrogen Catabolite Repression Activator Balances Fungal Nutrient Utilization and Virulence in the Insect Fungal Pathogen Beauveria bassiana. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:646-659. [PMID: 36584226 DOI: 10.1021/acs.jafc.2c07047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
In many fungi, the AreA GATA-type transcription factor mediates nitrogen catabolite repression affecting fungal development and, where applicable, virulence. Here, we investigated the functions of AreA in the fungal entomopathogen and plant endophyte Beauveria bassiana using knockdown of gene expression. The antiAreA mutants were impaired in nitrogen utilization and showed increased sensitivities to osmotic stressors but increased tolerances to oxidative/hypoxia stresses. Repression of BbAreA caused overall minimal effects on fungal virulence. The minor effects on virulence appeared to be due in part to competing secondary effects where host defense phenoloxidase activity was significantly decreased, but production of the fungal metabolite oosporein was increased and hyphal body development was impaired. Knockdown of BbAreA expression also resulted in impairment in ability of the fungus to associate with host plants. These data implicate that BbAreA likely acts as a regulator to balance fungal nutrient utilization, pathogenicity, and mutualism, facilitating the fungal occupation of host niches.
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Affiliation(s)
- Zhibing Luo
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Qiyan Chen
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Yufeng Su
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Shasha Hu
- Department of Biological Sciences, Brock University, St. Catharines, Ontario L2S 3A1, Canada
| | - Nemat O Keyhani
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611, United States
| | - Junyao Wang
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Chenhua Zhu
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Teng Zhou
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Yunxia Pan
- College of Engineering and Technology, Southwest University, Chongqing 400715, P. R. China
| | - Michael J Bidochka
- Department of Biological Sciences, Brock University, St. Catharines, Ontario L2S 3A1, Canada
| | - Yongjun Zhang
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
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Mohamed RA, Guo CT, Xu SY, Ying SH, Feng MG. Characterization of BbKlf1 as a novel transcription factor vital for asexual and infection cycles of Beauveria bassiana. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:719-731. [PMID: 35851566 DOI: 10.1111/1758-2229.13107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 06/19/2022] [Indexed: 06/15/2023]
Abstract
The large family of C2H2-type zinc finger transcription factors (TFs) comprise the Kruppel-like factors (KLFs) that evolved relatively late in eukaryotes but remain unexplored in filamentous fungi. Here, we report that an orthologue (BbKlf1) of yeast Klf1 mediating cell wall integrity (CWI) is a wide-spectrum TF evidently localized in nucleus and cytoplasm in Beauveria bassiana. BbKlf1 features conserved domains and multiple DNA-binding motifs predicted to bind multiple promoter DNA fragments of target genes across asexual developmental and stress-responsive pathways. Despite limited impact on normal colony growth, deletion of Bbklf1 resulted in impaired CWI and hypersensitivity to Congo red-induced cell wall stress. Also, the deletion mutant was severely compromised in tolerance to oxidative and osmotic stresses, hyphal septation and differentiation, conidiation capacity (reduced by 95%), conidial quality (viability and hydrocarbon epitope pattern) and virulence. Importantly, these phenotypes correlated well with sharply repressed or nearly abolished expressions of those genes required for or involved in chitin biosynthesis, antioxidant activity, cell division and differentiation, aerial conidiation and conidial maturation. These findings indicate an essentiality of BbKlf1 for the asexual and insect-pathogenic lifecycles of B. bassiana and a novel scenario much beyond the yeast orthologue-mediated CWI, suggesting important roles of its orthologues in filamentous fungi.
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Affiliation(s)
- Rehab Abdelmonem Mohamed
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chong-Tao Guo
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Si-Yuan Xu
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Sheng-Hua Ying
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ming-Guang Feng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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Song D, Jin Y, Shi Y, Xia Y, Peng G. The carbon catabolite repressor CreA is an essential virulence factor of Metarhizium acridum against Locusta migratoria. PEST MANAGEMENT SCIENCE 2022; 78:3676-3684. [PMID: 35613131 DOI: 10.1002/ps.7010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 05/04/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND CreA has been proved to be a core gene in asexual conidiation in Metarhizium acridum, which regulates the shift of normal conidiation and microcycle conidiation. At present, research on CreA in fungi has focused on carbon source metabolism. There is a lack of research on the effect of CreA in virulence of pathogenic fungi. RESULTS The virulence of the MaCreA disrupted strain (ΔMaCreA) for Locusta migratoria was lost by topical inoculation bioassay. The formation rate and turgor pressure of the appressoria decreased. Growth of ΔMaCreA in host hemolymph was delayed, and the number of hyphal bodies was significantly reduced. The conidial cell wall of ΔMaCreA became thicker, the mannan content decreased, and the chitin content increased significantly, and it was more sensitive to calcofluor white and Congo Red. α-1,3-Glucan and β-1,3-glucan are more exposed on the surface of ΔMaCreA conidia than on the wild type. Lmspätzle and Lmcactus, the immune response genes in the host Toll pathway, showed stronger transcriptional activities at the early stage of ΔMaCreA invasion. The phenoloxidase activity assay also showed stronger immunostimulation by ΔMaCreA in vitro. CONCLUSION The main reasons for the loss of virulence of ΔMaCreA in the topical inoculation were the reduced penetration ability of appressoria, limited growth in hemolymph and stronger insect immunostimulation of ΔMaCreA. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Dongxu Song
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, China
- Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, China
| | - Yumei Jin
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, China
- Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, China
| | - Youhui Shi
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, China
- Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, China
| | - Yuxian Xia
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, China
- Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, China
| | - Guoxiong Peng
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, China
- Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, China
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FluG and FluG-like FlrA Coregulate Manifold Gene Sets Vital for Fungal Insect-Pathogenic Lifestyle but Not Involved in Asexual Development. mSystems 2022; 7:e0031822. [PMID: 35862810 PMCID: PMC9426541 DOI: 10.1128/msystems.00318-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The central developmental pathway (CDP) activator gene brlA is activated by the upstream genes fluG and flbA–flbE in Aspergillus nidulans. Increasing evidences of fungal genome divergence make it necessary to clarify whether such genetic principles fit Pezizomycotina. Previously, fluG disruption resulted in limited conidiation defect and little effect on the expression of brlA and flbA–flbE in Beauveria bassiana possessing the other FluG-like regulator FlrA. Here, single-disruption (SD) mutants of flrA and double-disruption (DD) mutants of flrA and fluG were analyzed to clarify whether FlrA and FluG are upstream regulators of key CDP genes. Despite similar subcellular localization, no protein-protein interaction was detected between FlrA and FluG, suggesting mutual independence. Three flrA SD mutants showed phenotypes similar to those previously described for ΔfluG, including limited conidiation defect, facilitated blastospore production, impaired spore quality, blocked host infection, delayed proliferation in vivo, attenuated virulence, and increased sensitivities to multiple stresses. Three DD mutants resembled the SD mutants in all phenotypes except more compromised pathogenicity and tolerance to heat shock- or calcofluor white-induced stress. No CDP gene appeared in 1,622 and 2,234 genes dysregulated in the ΔflrA and ΔfluG mutants, respectively. The majority (up/down ratio: 540:875) of those dysregulated genes were co-upregulated or co-downregulated at similar levels in the two mutants. These findings unravel novel roles for flrA and fluG in coregulating manifold gene sets vital for fungal adaptation to insect-pathogenic lifestyle and environment but not involved in CDP activation. IMPORTANCE FluG is a core regulator upstream of central developmental pathway (CDP) in Aspergillus nidulans but multiple FluG-like regulators (FLRs) remain functionally uncharacterized in ascomycetes. Our previous study revealed no role for FluG in the CDP activation and an existence of sole FLR (FlrA) in an insect-pathogenic fungus. This study reveals a similarity of FlrA to FluG in domain architecture and subcellular localization. Experimental data from analyses of targeted single- and double-gene knockout mutants demonstrate similar roles of FrlA and FluG in stress tolerance and infection cycle but no role of either in CDP activation. Transcriptomic analyses reveal that FlrA and FluG coregulate a large number of same genes at similar levels. However, the regulated genes include no key CDP gene. These findings uncover that FlrA and FluG play similar roles in the fungal adaptation to insect-pathogenic lifestyle and environment but no role in the activation of CDP.
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Ren K, Mou YN, Ying SH, Feng MG. Conserved and Noncanonical Activities of Two Histone H3K36 Methyltransferases Required for Insect-Pathogenic Lifestyle of Beauveria bassiana. J Fungi (Basel) 2021; 7:956. [PMID: 34829243 PMCID: PMC8623635 DOI: 10.3390/jof7110956] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/06/2021] [Accepted: 11/10/2021] [Indexed: 12/21/2022] Open
Abstract
Set2 and Ash1 are histone methyltransferases (KMTs) in the KMT3 family normally used to catalyze methylation of histone H3K36 (H3K36me) but remain unexplored in fungal insect pathogens. Here, we report broader/greater roles of Set2 and Ash1 in mono-/di-/trimethylation (me1/me2/me3) of H3K4 than of H3K36 in Beauveria bassiana and function similarly to Set1/KMT2, which has been reported to catalyze H3K4me3 as an epigenetic mark of cre1 (carbon catabolite repressor) to upregulate the classes I and II hydrophobin genes hyd1 and hyd2 required for conidial hydrophobicity and adherence to insect cuticle. H3K4me3 was more attenuated than H3K36me3 in the absence of set2 (72% versus 67%) or ash1 (92% versus 12%), leading to sharply repressed or nearly abolished expression of cre1, hyd1 and hyd2, as well as reduced hydrophobicity. Consequently, the delta-set2 and delta-ash1 mutants were differentially compromised in radial growth on various media or under different stresses, aerial conidiation under normal culture conditions, virulence, and cellular events crucial for normal cuticle infection and hemocoel colonization, accompanied by transcriptional repression of subsets of genes involved in or required for asexual development and multiple stress responses. These findings unravel novel roles of Set2 and Ash1 in the co-catalysis of usually Set1-reliant H3K4me3 required for fungal insect-pathogenic lifestyle.
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Affiliation(s)
| | | | | | - Ming-Guang Feng
- MOE Laboratory of Biosystems Homeostasis & Protection, Collegeof Life Sciences, Zhejiang University, Hangzhou 310058, China; (K.R.); (Y.-N.M.); (S.-H.Y.)
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