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Li J, Wu M, Igarashi Y, Luo F, Chang P. Agrobacterium tumefaciens-mediated transformation of the white-rot fungus Dichomitus squalens. J Microbiol Methods 2023; 214:106842. [PMID: 37827437 DOI: 10.1016/j.mimet.2023.106842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/08/2023] [Accepted: 10/09/2023] [Indexed: 10/14/2023]
Abstract
Dichomitus squalens is an efficient white-rot fungus that generates a wide range of extracellular enzymes to degrade lignocellulose in nature. Although a protoplast-mediated transformation method for D. squalens has been developed, the transformation efficiency remains low. Here, we established a highly efficient Agrobacterium tumefaciens-mediated transformation (ATMT) procedure for D. squalens by transferring a binary vector harboring the neomycin phosphotransferase II (nptII) resistance gene fused with DsRed-Express2, under the control of the native glyceraldehyde-3-phosphate dehydrogenase (GPD) gene promoter. Key factors affecting the efficiency of transformation were tested. A. tumefaciens EHA105 strain with a cell density of 0.4 OD600nm and 96 h co-cultivation resulted in the highest transformation efficiency, with an average of 98 ± 11 transformants per co-cultivation plate. Besides, the strong expression of DsRed-Express2 indicates the effectiveness of the DsGPD promoter in driving gene expression in D. squalens. This ATMT system of D. squalens would be beneficial for its molecular genetic studies.
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Affiliation(s)
- Jing Li
- Chongqing Key Laboratory of Bioresource, Development for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Min Wu
- Chongqing Key Laboratory of Bioresource, Development for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yasuo Igarashi
- Chongqing Key Laboratory of Bioresource, Development for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Feng Luo
- Chongqing Key Laboratory of Bioresource, Development for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Peng Chang
- Chongqing Key Laboratory of Bioresource, Development for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, China.
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Kowalczyk JE, Saha S, Mäkelä MR. Application of CRISPR/Cas9 Tools for Genome Editing in the White-Rot Fungus Dichomitus squalens. Biomolecules 2021; 11:1526. [PMID: 34680159 PMCID: PMC8533725 DOI: 10.3390/biom11101526] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/04/2021] [Accepted: 10/12/2021] [Indexed: 12/26/2022] Open
Abstract
Dichomitus squalens is an emerging reference species that can be used to investigate white-rot fungal plant biomass degradation, as it has flexible physiology to utilize different types of biomass as sources of carbon and energy. Recent comparative (post-) genomic studies on D. squalens resulted in an increasingly detailed knowledge of the genes and enzymes involved in the lignocellulose breakdown in this fungus and showed a complex transcriptional response in the presence of lignocellulose-derived compounds. To fully utilize this increasing amount of data, efficient and reliable genetic manipulation tools are needed, e.g., to characterize the function of certain proteins in vivo and facilitate the construction of strains with enhanced lignocellulolytic capabilities. However, precise genome alterations are often very difficult in wild-type basidiomycetes partially due to extremely low frequencies of homology directed recombination (HDR) and limited availability of selectable markers. To overcome these obstacles, we assessed various Cas9-single guide RNA (sgRNA) ribonucleoprotein (RNP) -based strategies for selectable homology and non-homologous end joining (NHEJ) -based gene editing in D. squalens. We also showed an induction of HDR-based genetic modifications by using single-stranded oligodeoxynucleotides (ssODNs) in a basidiomycete fungus for the first time. This paper provides directions for the application of targeted CRISPR/Cas9-based genome editing in D. squalens and other wild-type (basidiomycete) fungi.
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Affiliation(s)
| | | | - Miia R. Mäkelä
- Department of Microbiology, University of Helsinki, Viikinkaari 9, 00790 Helsinki, Finland; (J.E.K.); (S.S.)
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Kowalczyk JE, Peng M, Pawlowski M, Lipzen A, Ng V, Singan V, Wang M, Grigoriev IV, Mäkelä MR. The White-Rot Basidiomycete Dichomitus squalens Shows Highly Specific Transcriptional Response to Lignocellulose-Related Aromatic Compounds. Front Bioeng Biotechnol 2019; 7:229. [PMID: 31616664 PMCID: PMC6763618 DOI: 10.3389/fbioe.2019.00229] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 09/05/2019] [Indexed: 11/13/2022] Open
Abstract
Lignocellulosic plant biomass is an important feedstock for bio-based economy. In particular, it is an abundant renewable source of aromatic compounds, which are present as part of lignin, as side-groups of xylan and pectin, and in other forms, such as tannins. As filamentous fungi are the main organisms that modify and degrade lignocellulose, they have developed a versatile metabolism to convert the aromatic compounds that are toxic at relatively low concentrations to less toxic ones. During this process, fungi form metabolites some of which represent high-value platform chemicals or important chemical building blocks, such as benzoic, vanillic, and protocatechuic acid. Especially basidiomycete white-rot fungi with unique ability to degrade the recalcitrant lignin polymer are expected to perform highly efficient enzymatic conversions of aromatic compounds, thus having huge potential for biotechnological exploitation. However, the aromatic metabolism of basidiomycete fungi is poorly studied and knowledge on them is based on the combined results of studies in variety of species, leaving the overall picture in each organism unclear. Dichomitus squalens is an efficiently wood-degrading white-rot basidiomycete that produces a diverse set of extracellular enzymes targeted for lignocellulose degradation, including oxidative enzymes that act on lignin. Our recent study showed that several intra- and extracellular aromatic compounds were produced when D. squalens was cultivated on spruce wood, indicating also versatile aromatic metabolic abilities for this species. In order to provide the first molecular level systematic insight into the conversion of plant biomass derived aromatic compounds by basidiomycete fungi, we analyzed the transcriptomes of D. squalens when grown with 10 different lignocellulose-related aromatic monomers. Significant differences for example with respect to the expression of lignocellulose degradation related genes, but also putative genes encoding transporters and catabolic pathway genes were observed between the cultivations supplemented with the different aromatic compounds. The results demonstrate that the transcriptional response of D. squalens is highly dependent on the specific aromatic compounds present suggesting that instead of a common regulatory system, fine-tuned regulation is needed for aromatic metabolism.
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Affiliation(s)
| | - Mao Peng
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute and Fungal Molecular Physiology, Utrecht University, Utrecht, Netherlands
| | - Megan Pawlowski
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA, United States
| | - Anna Lipzen
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA, United States
| | - Vivian Ng
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA, United States
| | - Vasanth Singan
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA, United States
| | - Mei Wang
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA, United States
| | - Igor V Grigoriev
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA, United States
| | - Miia R Mäkelä
- Department of Microbiology, University of Helsinki, Helsinki, Finland
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Daly P, Slaghek GG, Casado López S, Wiebenga A, Hilden KS, de Vries RP, Mäkelä MR. Genetic transformation of the white-rot fungus Dichomitus squalens using a new commercial protoplasting cocktail. J Microbiol Methods 2017; 143:38-43. [PMID: 28987554 DOI: 10.1016/j.mimet.2017.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 10/03/2017] [Accepted: 10/03/2017] [Indexed: 10/18/2022]
Abstract
D. squalens, a white-rot fungus that efficiently degrades lignocellulose in nature, can be used in various biotechnological applications and has several strains with sequenced and annotated genomes. Here we present a method for the transformation of this basidiomycete fungus, using a recently introduced commercial ascomycete protoplasting enzyme cocktail, Protoplast F. In protoplasting of D. squalens mycelia, Protoplast F outperformed two other cocktails while releasing similar amounts of protoplasts to a third cocktail. The protoplasts released using Protoplast F had a regeneration rate of 12.5% (±6 SE). Using Protoplast F, the D. squalens monokaryon CBS464.89 was conferred with resistance to the antibiotics hygromycin and G418 via polyethylene glycol mediated protoplast transformation with resistance cassettes expressing the hygromycin phosphotransferase (hph) and neomycin phosphotransferase (nptII) genes, respectively. The hph gene was expressed in D. squalens using heterologous promoters from genes encoding β-tubulin or glyceraldehyde 3-phosphate dehydrogenase. A Southern blot confirmed integration of a resistance cassette into the D. squalens genome. An average of six transformants (±2 SE) were obtained when at least several million protoplasts were used (a transformation efficiency of 0.8 (±0.3 SE) transformants per μg DNA). Transformation of D. squalens demonstrates the suitability of the Protoplast F cocktail for basidiomycete transformation and furthermore can facilitate understanding of basidiomycete gene function and development of improved strains for biotechnological applications.
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Affiliation(s)
- Paul Daly
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Gillian G Slaghek
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Sara Casado López
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Ad Wiebenga
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Kristiina S Hilden
- Department of Food and Environmental Sciences, University of Helsinki, Viikinkaari 9, Helsinki, Finland
| | - Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands; Department of Food and Environmental Sciences, University of Helsinki, Viikinkaari 9, Helsinki, Finland
| | - Miia R Mäkelä
- Department of Food and Environmental Sciences, University of Helsinki, Viikinkaari 9, Helsinki, Finland.
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Patyshakuliyeva A, Mäkelä MR, Sietiö OM, de Vries RP, Hildén KS. An improved and reproducible protocol for the extraction of high quality fungal RNA from plant biomass substrates. Fungal Genet Biol 2014; 72:201-6. [PMID: 24951842 DOI: 10.1016/j.fgb.2014.06.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 05/20/2014] [Accepted: 06/08/2014] [Indexed: 11/23/2022]
Abstract
Isolation of high quantity and quality RNA is a crucial step in the detection of meaningful gene expression data. Obtaining intact fungal RNA from complex lignocellulosic substrates is often difficult, producing low integrity RNA which perform poorly in downstream applications. In this study we developed an RNA extraction method using CsCl centrifugation procedure, modified from previous reports and adapted for isolation of RNA from plant biomass. This method provided high level of integrity and good quantity of RNA which were suitable for reliable analyses of gene expression and produced consistent and reproducible results.
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Rytioja J, Hildén K, Hatakka A, Mäkelä MR. Transcriptional analysis of selected cellulose-acting enzymes encoding genes of the white-rot fungus Dichomitus squalens on spruce wood and microcrystalline cellulose. Fungal Genet Biol 2014; 72:91-98. [PMID: 24394946 DOI: 10.1016/j.fgb.2013.12.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 12/20/2013] [Accepted: 12/23/2013] [Indexed: 10/25/2022]
Abstract
The recent discovery of oxidative cellulose degradation enhancing enzymes has considerably changed the traditional concept of hydrolytic cellulose degradation. The relative expression levels of ten cellulose-acting enzyme encoding genes of the white-rot fungus Dichomitus squalens were studied on solid-state spruce wood and in microcrystalline Avicel cellulose cultures. From the cellobiohydrolase encoding genes, cel7c was detected at the highest level and showed constitutive expression whereas variable transcript levels were detected for cel7a, cel7b and cel6 in the course of four-week spruce cultivation. The cellulolytic enzyme activities detected in the liquid cultures were consistent with the transcript levels. Interestingly, the selected lytic polysaccharide monooxygenase (LPMO) encoding genes were expressed in both cultures, but showed different transcription patterns on wood compared to those in submerged microcrystalline cellulose cultures. On spruce wood, higher transcript levels were detected for the lpmos carrying cellulose binding module (CBM) than for the lpmos without CBMs. In both cultures, the expression levels of the lpmo genes were generally higher than the levels of cellobiose dehydrogenase (CDH) encoding genes. Based on the results of this work, the oxidative cellulose cleaving enzymes of D. squalens have essential role in cellulose degrading machinery of the fungus.
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Affiliation(s)
- Johanna Rytioja
- Department of Food and Environmental Sciences, Division of Microbiology and Biotechnology, University of Helsinki, Viikki Biocenter 1, Finland
| | - Kristiina Hildén
- Department of Food and Environmental Sciences, Division of Microbiology and Biotechnology, University of Helsinki, Viikki Biocenter 1, Finland
| | - Annele Hatakka
- Department of Food and Environmental Sciences, Division of Microbiology and Biotechnology, University of Helsinki, Viikki Biocenter 1, Finland
| | - Miia R Mäkelä
- Department of Food and Environmental Sciences, Division of Microbiology and Biotechnology, University of Helsinki, Viikki Biocenter 1, Finland.
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