1
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Kunitake E, Kawaguchi T, Tani S. Independent, cooperative regulation of cellulolytic genes by paralogous transcription factors ClbR and ClbR2 in Aspergillus aculeatus. Biosci Biotechnol Biochem 2024; 88:212-219. [PMID: 37947258 DOI: 10.1093/bbb/zbad156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023]
Abstract
The cellobiose-responsive regulator ClbR, a Zn(II)2Cys6 binuclear-cluster transcription factor, is a positive regulator of carbohydrate-active enzyme (CAZyme) genes responsive to cellulose in Aspergillus aculeatus. Because Zn(II)2Cys6 transcription factors tend to dimerize with proteins of the same family, we searched for a counterpart of ClbR and identified ClbR2, which is 42% identical to ClbR, as an interacting partner of ClbR by yeast two-hybrid screening. Genetic analyses suggested that ClbR and ClbR2 cooperatively regulate the expression of CAZyme genes in response to cellulose and 1,4-β-mannobiose in A. aculeatus. CAZyme genes under the control of the transcription factor ManR were regulated by ClbR and ClbR2, whereas those controlled by the transcription factor XlnR were regulated by ClbR, but not ClbR2. These findings suggest that ClbR participates in multiple regulatory pathways in A. aculeatus by altering an interacting factor.
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Affiliation(s)
- Emi Kunitake
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University , Sakai, Japan
- Graduate School of Bioresources, Mie University , Tsu, Japan
| | - Takashi Kawaguchi
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University , Sakai, Japan
- Graduate School of Agriculture, Osaka Metropolitan University , Sakai, Japan
| | - Shuji Tani
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University , Sakai, Japan
- Graduate School of Agriculture, Osaka Metropolitan University , Sakai, Japan
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2
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Kun RS, Garrigues S, Peng M, Keymanesh K, Lipzen A, Ng V, Tejomurthula S, Grigoriev IV, de Vries RP. The transcriptional activator ClrB is crucial for the degradation of soybean hulls and guar gum in Aspergillus niger. Fungal Genet Biol 2023; 165:103781. [PMID: 36801368 DOI: 10.1016/j.fgb.2023.103781] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 02/07/2023] [Accepted: 02/14/2023] [Indexed: 02/18/2023]
Abstract
Low-cost plant substrates, such as soybean hulls, are used for various industrial applications. Filamentous fungi are important producers of Carbohydrate Active enZymes (CAZymes) required for the degradation of these plant biomass substrates. CAZyme production is tightly regulated by several transcriptional activators and repressors. One such transcriptional activator is CLR-2/ClrB/ManR, which has been identified as a regulator of cellulase and mannanase production in several fungi. However, the regulatory network governing the expression of cellulase and mannanase encoding genes has been reported to differ between fungal species. Previous studies showed that Aspergillus niger ClrB is involved in the regulation of (hemi-)cellulose degradation, although its regulon has not yet been identified. To reveal its regulon, we cultivated an A. niger ΔclrB mutant and control strain on guar gum (a galactomannan-rich substrate) and soybean hulls (containing galactomannan, xylan, xyloglucan, pectin and cellulose) to identify the genes that are regulated by ClrB. Gene expression data and growth profiling showed that ClrB is indispensable for growth on cellulose and galactomannan and highly contributes to growth on xyloglucan in this fungus. Therefore, we show that A. niger ClrB is crucial for the utilization of guar gum and the agricultural substrate, soybean hulls. Moreover, we show that mannobiose is most likely the physiological inducer of ClrB in A. niger and not cellobiose, which is considered to be the inducer of N. crassa CLR-2 and A. nidulans ClrB.
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Affiliation(s)
- Roland S Kun
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Sandra Garrigues
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Mao Peng
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Keykhosrow Keymanesh
- USA Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA 94720, United States
| | - Anna Lipzen
- USA Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA 94720, United States
| | - Vivian Ng
- USA Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA 94720, United States
| | - Sravanthi Tejomurthula
- USA Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA 94720, United States
| | - Igor V Grigoriev
- USA Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA 94720, United States
| | - Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands.
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3
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Zhang X, Hu Y, Liu G, Liu M, Li Z, Zhao J, Song X, Zhong Y, Qu Y, Wang L, Qin Y. The complex Tup1-Cyc8 bridges transcription factor ClrB and putative histone methyltransferase LaeA to activate the expression of cellulolytic genes. Mol Microbiol 2022; 117:1002-1022. [PMID: 35072962 DOI: 10.1111/mmi.14885] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 11/28/2022]
Abstract
The degradation of lignocellulosic biomass by cellulolytic enzymes is involved in the global carbon cycle. The hydrolysis of lignocellulosic biomass into fermentable sugars is potential as excellent industrial resource to produce a variety of chemical products. The production of cellulolytic enzymes is regulated mainly at the transcriptional level in filamentous fungi. Transcription factor ClrB and the putative histone methyltransferase LaeA, are both necessary for the expression of cellulolytic genes. However, the mechanism by which transcription factors and methyltransferase coordinately regulate cellulolytic genes is still unknown. Here, we reveal a transcriptional regulatory mechanism involving Penicillium oxalicum transcription factor ClrB (PoClrB), complex Tup1-Cyc8, and putative histone methyltransferase LaeA (PoLaeA). As the transcription factor, PoClrB binds the targeted promoters of cellulolytic genes, recruits PoTup1-Cyc8 complex via direct interaction with PoTup1. PoTup1 interacts with PoCyc8 to form the coactivator complex PoTup1-Cyc8. Then, PoTup1 recruits putative histone methyltransferase PoLaeA to modify the chromatin structure of the upstream region of cellulolytic genes, thereby facilitating the binding of transcription machinery to activating the corresponding cellulolytic gene expression. Our results contribute to a better understanding of complex transcriptional regulation mechanisms of cellulolytic genes and will be valuable for lignocellulosic biorefining.
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Affiliation(s)
- Xiujun Zhang
- National Glycoengineering Research Center, Shandong University, Qingdao, China.,State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China.,School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Yueyan Hu
- National Glycoengineering Research Center, Shandong University, Qingdao, China.,State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Guodong Liu
- National Glycoengineering Research Center, Shandong University, Qingdao, China.,State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Meng Liu
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Zhonghai Li
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China.,State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Xin Song
- National Glycoengineering Research Center, Shandong University, Qingdao, China.,State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Yaohua Zhong
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Yinbo Qu
- National Glycoengineering Research Center, Shandong University, Qingdao, China.,State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Yuqi Qin
- National Glycoengineering Research Center, Shandong University, Qingdao, China.,State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
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4
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Kun RS, Garrigues S, Di Falco M, Tsang A, de Vries RP. Blocking utilization of major plant biomass polysaccharides leads Aspergillus niger towards utilization of minor components. Microb Biotechnol 2021; 14:1683-1698. [PMID: 34114741 PMCID: PMC8313289 DOI: 10.1111/1751-7915.13835] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/08/2021] [Accepted: 05/10/2021] [Indexed: 11/28/2022] Open
Abstract
Fungi produce a wide range of enzymes that allow them to grow on diverse plant biomass. Wheat bran is a low-cost substrate with high potential for biotechnological applications. It mainly contains cellulose and (arabino)xylan, as well as starch, proteins, lipids and lignin to a lesser extent. In this study, we dissected the regulatory network governing wheat bran degradation in Aspergillus niger to assess the relative contribution of the regulators to the utilization of this plant biomass substrate. Deletion of genes encoding transcription factors involved in (hemi-)cellulose utilization (XlnR, AraR, ClrA and ClrB) individually and in combination significantly reduced production of polysaccharide-degrading enzymes, but retained substantial growth on wheat bran. Proteomic analysis suggested the ability of A. niger to grow on other carbon components, such as starch, which was confirmed by the additional deletion of the amylolytic regulator AmyR. Growth was further reduced but not impaired, indicating that other minor components provide sufficient energy for residual growth, displaying the flexibility of A. niger, and likely other fungi, in carbon utilization. Better understanding of the complexity and flexibility of fungal regulatory networks will facilitate the generation of more efficient fungal cell factories that use plant biomass as a substrate.
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Affiliation(s)
- Roland S. Kun
- Fungal PhysiologyWesterdijk Fungal Biodiversity Institute & Fungal Molecular PhysiologyUtrecht UniversityUppsalalaan 8Utrecht3584 CTThe Netherlands
| | - Sandra Garrigues
- Fungal PhysiologyWesterdijk Fungal Biodiversity Institute & Fungal Molecular PhysiologyUtrecht UniversityUppsalalaan 8Utrecht3584 CTThe Netherlands
| | - Marcos Di Falco
- Centre for Structural and Functional GenomicsConcordia University7141 Sherbrooke Street WestMontrealQCH4B 1R6Canada
| | - Adrian Tsang
- Centre for Structural and Functional GenomicsConcordia University7141 Sherbrooke Street WestMontrealQCH4B 1R6Canada
| | - Ronald P. de Vries
- Fungal PhysiologyWesterdijk Fungal Biodiversity Institute & Fungal Molecular PhysiologyUtrecht UniversityUppsalalaan 8Utrecht3584 CTThe Netherlands
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5
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Gao L, He X, Guo Y, Wu Z, Zhao J, Liu G, Qu Y. Combinatorial Engineering of Transcriptional Activators in Penicillium oxalicum for Improved Production of Corn-Fiber-Degrading Enzymes. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:2539-2548. [PMID: 33619954 DOI: 10.1021/acs.jafc.0c07659] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Enzymatic conversion of corn fiber to fermentable sugars is beneficial to improving the economic efficiency of corn processing. In this work, the filamentous fungus Penicillium oxalicum was found to secrete enzymes for efficient saccharification of un-pretreated corn fiber. Separate engineering of transcriptional activators ClrB, XlnR, and AraR led to enhanced production of different sets of lignocellulolytic enzymes. Particularly, the enzymes produced by XlnR- and AraR-engineered strains showed a synergistic effect in corn fiber saccharification. Combinatorial engineering of all three activators generated a strain MCAX with 3.1- to 51.0-fold increases in lignocellulolytic enzyme production compared with the parent strain. In addition, the enzymes of strain MCAX released significantly more fermentable sugars from corn fiber than those of the parent strain at the same protein dosage. The results suggest that this strain has potential for on-site production of enzymes for corn fiber saccharification.
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Affiliation(s)
- Liwei Gao
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, 266237 Qingdao, China
- Tobacco Research Institute of Chinese Academy of Agricultural Sciences, 11 Keyuanjingsi Road, 266101 Qingdao, China
| | - Xin He
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, 266237 Qingdao, China
| | - Yingjie Guo
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, 266237 Qingdao, China
| | - Zehua Wu
- Research and Development Department, Shandong Shouguang Juneng Golden Corn Co., Ltd., Anshun Street, Shouguang, 262700 Weifang, China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, 266237 Qingdao, China
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, 266237 Qingdao, China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, 266237 Qingdao, China
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6
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Tsumura R, Sawada K, Kunitake E, Sumitani JI, Kawaguchi T, Tani S. A component of the septation initiation network complex, AaSepM, is involved in multiple cellulose-responsive signaling pathways in Aspergillus aculeatus. Appl Microbiol Biotechnol 2021; 105:1535-1546. [PMID: 33481069 DOI: 10.1007/s00253-021-11110-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 12/22/2020] [Accepted: 01/11/2021] [Indexed: 11/29/2022]
Abstract
Various carbohydrate-active enzymes in Aspergillus are produced in response to physiological inducers, which is regulated at the transcriptional level. To elucidate the induction mechanisms in Aspergillus, we screened for new regulators involved in cellulose-responsive induction from approximately 10,000 Aspergillus aculeatus T-DNA-inserted mutants. We constructed the T-DNA-inserted mutant library using the host strain harboring the orotidine 5'-monophosphate decarboxylase gene (pyrG) under the control of the FIII-avicelase gene (cbhI) promoter. Thus, candidate mutants deficient in cellulose-responsive induction were positively screened via counter selection against 5-fluoroorotic acid (5-FOA). Among less than two hundred 5-FOA-resistant mutants, one mutant that the T-DNA inserted into the AasepM locus reduced the cbhI expression in response to cellulose. Since AaSepM is similar to Schizosaccharomyces pombe Cdc14p (E-value, 2e-20; identities, 33%), which is a component of the septation initiation network (SIN)-complex, we constructed an AasepM deletion mutant (ΔAasepM). We analyzed the expression of cellulase and xylanase genes in response to cellulose, septation, and conidiation in ΔAasepM. The AasepM deletion leads to delayed septation and decreased formation of the conidium chain in A. aculeatus but does not affect hyphal growth on minimal media. We also confirmed AaSepM's involvement in multiple cellulose-responsive signaling pathways of cellulase and xylanase genes under the control of the ManR-dependent, XlnR-dependent, and ManR- and XlnR-independent signaling pathways. KEY POINTS : • A new regulator for cellulolytic gene expression has been identified. • AaSepM is involved in septation and conidiation in A. aculeatus. • AasepM is involved in multiple cellulose-responsive signaling pathways.
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Affiliation(s)
- Ryosuke Tsumura
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, 599-8531, Japan
| | - Kazumi Sawada
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, 599-8531, Japan
| | - Emi Kunitake
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, 599-8531, Japan.,Graduate School of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu, 514-8507, Japan
| | - Jun-Ichi Sumitani
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, 599-8531, Japan
| | - Takashi Kawaguchi
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, 599-8531, Japan
| | - Shuji Tani
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, 599-8531, Japan.
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7
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A mitogen-activated protein kinase PoxMK1 mediates regulation of the production of plant-biomass-degrading enzymes, vegetative growth, and pigment biosynthesis in Penicillium oxalicum. Appl Microbiol Biotechnol 2021; 105:661-678. [PMID: 33409610 DOI: 10.1007/s00253-020-11020-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/20/2020] [Accepted: 11/11/2020] [Indexed: 02/07/2023]
Abstract
Mitogen-activated protein kinase (MAPK) cascades are broadly conserved and play essential roles in multiple cellular processes, including fungal development, pathogenicity, and secondary metabolism. Their function, however, also exhibits species and strain specificity. Penicillium oxalicum secretes plant-biomass-degrading enzymes (PBDEs) that contribute to the carbon cycle in the natural environment and to utilization of lignocellulose in industrial processes. However, knowledge of the MAPK pathway in P. oxalicum has been relatively limited. In this study, comparative transcriptomic analysis of P. oxalicum, cultured on different carbon sources, found ten putative kinase genes with significantly modified transcriptional levels. Six of these putative kinase genes were knocked out in the parental strain ∆PoxKu70, and deletion of the gene, Fus3/Kss1-like PoxMK1 (POX00158), resulted in the largest reduction (91.1%) in filter paper cellulase production. Further tests revealed that the mutant ∆PoxMK1 lost 37.1 to 92.2% of PBDE production, under both submerged- and solid-state fermentation conditions, compared with ∆PoxKu70. In addition, the mutant ∆PoxMK1 had reduced vegetative growth and increased pigment biosynthesis. Comparative transcriptomic analysis showed that PoxMK1 deletion from P. oxalicum downregulated the expression of major PBDE genes and known regulatory genes such as PoxClrB and PoxCxrB, whereas the transcription of pigment biosynthesis-related genes was upregulated. Comparative phosphoproteomic analysis revealed that PoxMK1 deletion considerably modified phosphorylation of key transcription- and signal transduction-associated proteins, including transcription factors Mcm1 and Atf1, RNA polymerase II subunits Rpb1 and Rpb9, MAPK-associated Hog1 and Ste7, and cyclin-dependent kinase Kin28. These findings provide novel insights into understanding signal transduction and regulation of PBDE gene expression in fungi.Key points• PoxMK1 is involved in expression of PBDE- and pigment synthesis-related genes.• PoxMK1 is required for vegetative growth of P. oxalicum.• PoxMK1 is involved in phosphorylation of key TFs, kinases, and RNA polymerase II.
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8
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Hsu Y, Arioka M. In vitro and in vivo characterization of genes involved in mannan degradation in Neurospora crassa. Fungal Genet Biol 2020; 144:103441. [PMID: 32777385 DOI: 10.1016/j.fgb.2020.103441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 07/28/2020] [Accepted: 08/03/2020] [Indexed: 01/22/2023]
Abstract
To better understand the roles of genes involved in mannan degradation in filamentous fungi, in this study we searched, identified, and characterized one putative GH5 endo-β-mannanase (GH5-7) and two putative GH2 mannan-degrading enzymes (GH2-1 and GH2-4) in Neurospora crassa. Real-time RT-PCR analyses showed that the expression levels of these genes were significantly up-regulated when the cells were grown in mannan-containing media where the induction level of gh5-7 was the highest. All three proteins were heterologously expressed and purified. GH5-7 displayed a substrate preference toward galactomannan by showing 10-times higher catalytic efficiency than to linear β-mannan. In contrast, GH2-1 preferred short manno-oligosaccharides or β-mannan as substrates. Compared to the wild type strain, the growth of Δgh5-7 and Δgh5-7Δgh2-4 mutants, but not Δgh2-1, Δgh2-4, and Δgh2-1Δgh2-4 mutants, was poor in the cultures containing glucomannan or galactomannan as the sole carbon source, suggesting that GH5-7 plays a critical role in the utilization of heteromannans in vivo. On the other hand, all the mutants showed significantly slow growth when grown in the medium containing linear β-mannan. Collectively, these results indicate that N. crassa can utilize glucomannan and galactomannan without GH2-1 and GH2-4, but efficient degradation of β-mannan requires a concerted action of three enzymes, GH5-7, GH2-1, and GH2-4.
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Affiliation(s)
- Yunhan Hsu
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Manabu Arioka
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan; Collaborative Research Institute for Innovative Microbiology (CRIIM), The University of Tokyo, Japan.
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9
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Identification and Biochemical Characterization of Major β-Mannanase in Talaromyces cellulolyticus Mannanolytic System. Appl Biochem Biotechnol 2020; 192:616-631. [DOI: 10.1007/s12010-020-03350-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 05/22/2020] [Indexed: 01/06/2023]
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10
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Khosravi C, Kowalczyk JE, Chroumpi T, Battaglia E, Aguilar Pontes MV, Peng M, Wiebenga A, Ng V, Lipzen A, He G, Bauer D, Grigoriev IV, de Vries RP. Transcriptome analysis of Aspergillus niger xlnR and xkiA mutants grown on corn Stover and soybean hulls reveals a highly complex regulatory network. BMC Genomics 2019; 20:853. [PMID: 31726994 PMCID: PMC6854810 DOI: 10.1186/s12864-019-6235-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 10/28/2019] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Enzymatic plant biomass degradation by fungi is a highly complex process and one of the leading challenges in developing a biobased economy. Some industrial fungi (e.g. Aspergillus niger) have a long history of use with respect to plant biomass degradation and for that reason have become 'model' species for this topic. A. niger is a major industrial enzyme producer that has a broad ability to degrade plant based polysaccharides. A. niger wild-type, the (hemi-)cellulolytic regulator (xlnR) and xylulokinase (xkiA1) mutant strains were grown on a monocot (corn stover, CS) and dicot (soybean hulls, SBH) substrate. The xkiA1 mutant is unable to utilize the pentoses D-xylose and L-arabinose and the polysaccharide xylan, and was previously shown to accumulate inducers for the (hemi-)cellulolytic transcriptional activator XlnR and the arabinanolytic transcriptional activator AraR in the presence of pentoses, resulting in overexpression of their target genes. The xlnR mutant has reduced growth on xylan and down-regulation of its target genes. The mutants therefore have a similar phenotype on xylan, but an opposite transcriptional effect. D-xylose and L-arabinose are the most abundant monosaccharides after D-glucose in nearly all plant-derived biomass materials. In this study we evaluated the effect of the xlnR and xkiA1 mutation during growth on two pentose-rich substrates by transcriptome analysis. RESULTS Particular attention was given to CAZymes, metabolic pathways and transcription factors related to the plant biomass degradation. Genes coding for the main enzymes involved in plant biomass degradation were down-regulated at the beginning of the growth on CS and SBH. However, at a later time point, significant differences were found in the expression profiles of both mutants on CS compared to SBH. CONCLUSION This study demonstrates the high complexity of the plant biomass degradation process by fungi, by showing that mutant strains with fairly straightforward phenotypes on pure mono- and polysaccharides, have much less clear-cut phenotypes and transcriptomes on crude plant biomass.
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Affiliation(s)
- Claire Khosravi
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, the Netherlands
| | - Joanna E. Kowalczyk
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, the Netherlands
| | - Tania Chroumpi
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, the Netherlands
| | - Evy Battaglia
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, the Netherlands
| | - Maria-Victoria Aguilar Pontes
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, the Netherlands
| | - Mao Peng
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, the Netherlands
| | - Ad Wiebenga
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, the Netherlands
| | - Vivian Ng
- US Department of Energy Joint Genome Institute, Walnut Creek, CA USA
| | - Anna Lipzen
- US Department of Energy Joint Genome Institute, Walnut Creek, CA USA
| | - Guifen He
- US Department of Energy Joint Genome Institute, Walnut Creek, CA USA
| | - Diane Bauer
- US Department of Energy Joint Genome Institute, Walnut Creek, CA USA
| | - Igor V. Grigoriev
- US Department of Energy Joint Genome Institute, Walnut Creek, CA USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA USA
| | - Ronald P. de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, the Netherlands
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11
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Gao L, Xu Y, Song X, Li S, Xia C, Xu J, Qin Y, Liu G, Qu Y. Deletion of the middle region of the transcription factor ClrB in Penicillium oxalicum enables cellulase production in the presence of glucose. J Biol Chem 2019; 294:18685-18697. [PMID: 31659120 DOI: 10.1074/jbc.ra119.010863] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/21/2019] [Indexed: 11/06/2022] Open
Abstract
Enzymes that degrade lignocellulose to simple sugars are of great interest in research and for biotechnology because of their role in converting plant biomass to fuels and chemicals. The synthesis of cellulolytic enzymes in filamentous fungi is tightly regulated at the transcriptional level, with the transcriptional activator ClrB/CLR-2 playing a critical role in many species. In Penicillium oxalicum, clrB overexpression could not relieve the dependence of cellulase expression on cellulose as an inducer, suggesting that clrB is controlled post-transcriptionally. In this study, using a reporter gene system in yeast, we identified the C-terminal region of ClrB/CLR-2 as a transcriptional activation domain. Expression of clrBID , encoding a ClrB derivative in which the DNA-binding and transcriptional activation domains are fused together to remove the middle region, led to cellulase production in the absence of cellulose in P. oxalicum Strikingly, the clrBID -expressing strain produced cellulase on carbon sources that normally repress cellulase expression, including glucose and glycerol. Results from deletion of the carbon catabolite repressor gene creA in the clrBID -expressing strain suggested that the effect of clrBID is independent of CreA's repressive function. A similar modification of clrB in Aspergillus niger resulted in the production of a mannanase in glucose medium. Taken together, these results indicate that ClrB suppression under noninducing conditions involves its middle region, suggesting a potential strategy to engineer fungal strains for improved cellulase production on commonly used carbon sources.
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Affiliation(s)
- Liwei Gao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Yanning Xu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Xin Song
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Shiying Li
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Chengqiang Xia
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Jiadi Xu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China; National Glycoengineering Research Center, Shandong University, Qingdao 266237, China
| | - Yuqi Qin
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China; National Glycoengineering Research Center, Shandong University, Qingdao 266237, China
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China; National Glycoengineering Research Center, Shandong University, Qingdao 266237, China.
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China; National Glycoengineering Research Center, Shandong University, Qingdao 266237, China
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Comparison of the paralogous transcription factors AraR and XlnR in Aspergillus oryzae. Curr Genet 2018; 64:1245-1260. [PMID: 29654355 DOI: 10.1007/s00294-018-0837-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/08/2018] [Accepted: 04/11/2018] [Indexed: 10/17/2022]
Abstract
The paralogous transcription factors AraR and XlnR in Aspergillus regulate genes that are involved in degradation of cellulose and hemicellulose and catabolism of pentose. AraR and XlnR target the same genes for pentose catabolism but target different genes encoding enzymes for polysaccharide degradation. To uncover the relationship between these paralogous transcription factors, we examined their contribution to regulation of the PCP genes and compared their preferred recognition sequences. Both AraR and XlnR are involved in induction of all the pentose catabolic genes in A. oryzae except larA encoding L-arabinose reductase, which was regulated by AraR but not by XlnR. DNA-binding studies revealed that the recognition sequences of AraR and XlnR also differ only slightly; AraR prefers CGGDTAAW, while XlnR prefers CGGNTAAW. All the pentose catabolic genes possess at least one recognition site to which both AraR and XlnR can bind. Cooperative binding by the factors was not observed. Instead, they competed to bind to the shared sites. XlnR bound to the recognition sites mentioned above as a monomer, but bound to the sequence TTAGSCTAA on the xylanase promoters as a dimer. Consequently, AraR and XlnR have significantly similar, but not the same, DNA-binding properties. Such a slight difference in these paralogous transcription factors may lead to complex outputs in enzyme production depending on the concentrations of coexisting inducer molecules in the natural environment.
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13
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Kowalczyk JE, Lubbers RJM, Peng M, Battaglia E, Visser J, de Vries RP. Combinatorial control of gene expression in Aspergillus niger grown on sugar beet pectin. Sci Rep 2017; 7:12356. [PMID: 28955038 PMCID: PMC5617896 DOI: 10.1038/s41598-017-12362-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 09/07/2017] [Indexed: 01/06/2023] Open
Abstract
Aspergillus niger produces an arsenal of extracellular enzymes that allow synergistic degradation of plant biomass found in its environment. Pectin is a heteropolymer abundantly present in the primary cell wall of plants. The complex structure of pectin requires multiple enzymes to act together. Production of pectinolytic enzymes in A. niger is highly regulated, which allows flexible and efficient capture of nutrients. So far, three transcriptional activators have been linked to regulation of pectin degradation in A. niger. The L-rhamnose-responsive regulator RhaR controls the production of enzymes that degrade rhamnogalacturonan-I. The L-arabinose-responsive regulator AraR controls the production of enzymes that decompose the arabinan and arabinogalactan side chains of rhamnogalacturonan-II. The D-galacturonic acid-responsive regulator GaaR controls the production of enzymes that act on the polygalacturonic acid backbone of pectin. This project aims to better understand how RhaR, AraR and GaaR co-regulate pectin degradation. For that reason, we constructed single, double and triple disruptant strains of these regulators and analyzed their growth phenotype and pectinolytic gene expression in A. niger grown on sugar beet pectin.
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Affiliation(s)
- Joanna E Kowalczyk
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Ronnie J M Lubbers
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Mao Peng
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Evy Battaglia
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Jaap Visser
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands.
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14
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Conservation and diversity of the regulators of cellulolytic enzyme genes in Ascomycete fungi. Curr Genet 2017; 63:951-958. [DOI: 10.1007/s00294-017-0695-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 04/14/2017] [Accepted: 04/20/2017] [Indexed: 01/08/2023]
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