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Zou G, Xiao M, Chai S, Zhu Z, Wang Y, Zhou Z. Efficient genome editing in filamentous fungi via an improved CRISPR-Cas9 ribonucleoprotein method facilitated by chemical reagents. Microb Biotechnol 2021; 14:2343-2355. [PMID: 32841542 PMCID: PMC8601184 DOI: 10.1111/1751-7915.13652] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/29/2020] [Accepted: 07/29/2020] [Indexed: 12/21/2022] Open
Abstract
DNA double-strand break (DSB) repair induced by the RNA-programmed nuclease Cas9 has become a popular method for genome editing. Direct genome editing via Cas9-CRISPR gRNA (guide RNA) ribonucleoprotein (RNP) complexes assembled in vitro has also been successful in some fungi. However, the efficiency of direct RNP transformation into fungal protoplasts is currently too low. Here, we report an optimized genome editing approach for filamentous fungi based on RNPs facilitated by adding chemical reagents. We increased the transformation efficiency of RNPs significantly by adding Triton X-100 and prolonging the incubation time, and the editing efficiency reached 100% in Trichoderma reesei and Cordyceps militaris. The optimized RNP-based method also achieved efficient (56.52%) homologous recombination integration with short homology arms (20 bp) and gene disruption (7.37%) that excludes any foreign DNA (selection marker) in T. reesei. In particular, after adding reagents related to mitosis and cell division, the further optimized protocol showed an increased ratio of edited homokaryotic transformants (from 0% to 40.0% for inositol and 71.43% for benomyl) from Aspergillus oryzae, which contains multinucleate spores and protoplasts. Furthermore, the multi-target engineering efficiency of the optimized RNP transformation method was similar to those of methods based on in vivo expression of Cas9. This newly established genome editing system based on RNPs may be widely applicable to construction of genome-edited fungi for the food and medical industries, and has good prospects for commercialization.
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Affiliation(s)
- Gen Zou
- CAS‐Key Laboratory of Synthetic BiologyCAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and EcologyChinese Academy of ScienceFenglin Rd 300Shanghai200032China
- Shanghai Key Laboratory of Agricultural Genetics and BreedingInstitute of Edible FungiShanghai Academy of Agriculture Science1000 Jinqi Rd, FengxianShanghai201403China
| | - Meili Xiao
- CAS‐Key Laboratory of Synthetic BiologyCAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and EcologyChinese Academy of ScienceFenglin Rd 300Shanghai200032China
- University of Chinese Academy of SciencesBeijing100049China
| | - Shunxing Chai
- CAS‐Key Laboratory of Synthetic BiologyCAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and EcologyChinese Academy of ScienceFenglin Rd 300Shanghai200032China
- University of Chinese Academy of SciencesBeijing100049China
| | - Zhihua Zhu
- CAS‐Key Laboratory of Synthetic BiologyCAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and EcologyChinese Academy of ScienceFenglin Rd 300Shanghai200032China
- University of Chinese Academy of SciencesBeijing100049China
| | - Ying Wang
- Shanghai Key Laboratory of Agricultural Genetics and BreedingInstitute of Edible FungiShanghai Academy of Agriculture Science1000 Jinqi Rd, FengxianShanghai201403China
| | - Zhihua Zhou
- CAS‐Key Laboratory of Synthetic BiologyCAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and EcologyChinese Academy of ScienceFenglin Rd 300Shanghai200032China
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Yuan BH, Li H, Liu L, Du XH. Successful induction and recognition of conidiation, conidial germination and chlamydospore formation in pure culture of Morchella. Fungal Biol 2020; 125:285-293. [PMID: 33766307 DOI: 10.1016/j.funbio.2020.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 11/19/2020] [Accepted: 11/23/2020] [Indexed: 01/17/2023]
Abstract
Morels, fungi from the genus Morchella, are popular edible mushrooms. However, little knowledge of their asexual reproduction and inaccessible pure mitospores hamper illumination of their life cycle. Herein, we successfully induced conidiation, conidial germination and chlamydospore formation in pure culture of Morchella sextelata. Conidiation proceeded via four morphologically distinct stages: development of the conidiophore stalk, stalk branching, phialide differentiation, and conidium production. Terminal and intercalary chlamydospores were formed on conidial hyphae. The development of conidiophores occurred earlier, with more conidia produced, in cross-mating cultures than in single-spore cultures. Mature conidia were spherical and 2.5-8 μm in diameter, with a vast majority (nearly 99%) 2.5-5 μm in diameter. Each conidium contained one to three nuclei (80.2% conidia contained one nucleus, 19.1% contained two nuclei, and 0.7% contained three nuclei). The conidial nucleus diameter was 1-2 μm. The nuclear mitosis in detached conidia that was observed may benefit their colony initiation. Additionally, morel conidia formed conidial anastomosis tubes. Conidia (mitospores) likely not only function as spermatia, but also as reproductive propagules in Morchella. Further research is imperative to elucidate the relationship between the conidia and chlamydospores, and their unique function in the morel life cycle.
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Affiliation(s)
- Bin-Hong Yuan
- College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Huan Li
- College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Lu Liu
- College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Xi-Hui Du
- College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China.
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Yasui M, Oda K, Masuo S, Hosoda S, Katayama T, Maruyama JI, Takaya N, Takeshita N. Invasive growth of Aspergillus oryzae in rice koji and increase of nuclear number. Fungal Biol Biotechnol 2020; 7:8. [PMID: 32518660 PMCID: PMC7275602 DOI: 10.1186/s40694-020-00099-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/23/2020] [Indexed: 01/02/2023] Open
Abstract
Background 'Rice koji' is a solid culture of Aspergillus oryzae on steamed rice grains. Multiple parallel fermentation, wherein saccharification of rice by A. oryzae and alcohol fermentation by the budding yeast occur simultaneously, leads to the formation of a variety of ingredients of Japanese sake. In sake brewing, the degree of mycelial invasive growth into the steamed rice, called 'haze-komi', highly correlates with the digestibility and quality of rice koji, since the hyphae growing into the rice secrete amylases and digest starch. Results In this study, we investigated mycelial distribution of GFP-tagged A. oryzae in rice koji made with different types of rice, such as sake rice and eating rice, with 50 or 90% polishing rate to remove abundant proteins and lipids near the surface. In addition, we compared transcriptomes of A. oryzae in the different types of rice koji. Finally, we found that A. oryzae increases the nuclear number and hyphal width in the course of 1-3 days cultivation. Conclusions Our imaging analyses indicate that A. oryzae hyphae grew more deeply into 50% polished rice than 90% polished rice. The increases of nuclear number may be a selectively acquired characteristic for the high secretory capacity during the long history of cultivation of this species.
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Affiliation(s)
- Mizuki Yasui
- Microbiology Research Center for Sustainability (MiCS), Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Ken Oda
- National Research Institute of Brewing, 3-7-1 Kagamiyama, Higashi-hiroshima, Hiroshima, 739-0046 Japan
| | - Shunsuke Masuo
- Microbiology Research Center for Sustainability (MiCS), Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Shuji Hosoda
- Microbiology Research Center for Sustainability (MiCS), Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Takuya Katayama
- Department of Biotechnology, Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
| | - Jun-Ichi Maruyama
- Department of Biotechnology, Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
| | - Naoki Takaya
- Microbiology Research Center for Sustainability (MiCS), Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Norio Takeshita
- Microbiology Research Center for Sustainability (MiCS), Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
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Fungal spores: Highly variable and stress-resistant vehicles for distribution and spoilage. Food Microbiol 2018; 81:2-11. [PMID: 30910084 DOI: 10.1016/j.fm.2018.11.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 11/19/2018] [Accepted: 11/20/2018] [Indexed: 11/21/2022]
Abstract
This review highlights the variability of fungal spores with respect to cell type, mode of formation and stress resistance. The function of spores is to disperse fungi to new areas and to get them through difficult periods. This also makes them important vehicles for food contamination. Formation of spores is a complex process that is regulated by the cooperation of different transcription factors. The discussion of the biology of spore formation, with the genus Aspergillus as an example, points to possible novel ways to eradicate fungal spore production in food. Fungi can produce different types of spores, sexual and asexually, within the same colony. The absence or presence of sexual spore formation has led to a dual nomenclature for fungi. Molecular techniques have led to a revision of this nomenclature. A number of fungal species form sexual spores, which are exceptionally stress-resistant and survive pasteurization and other treatments. A meta-analysis is provided of numerous D-values of heat-resistant ascospores generated during the years. The relevance of fungal spores for food microbiology has been discussed.
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Rico-Munoz E, Samson RA, Houbraken J. Mould spoilage of foods and beverages: Using the right methodology. Food Microbiol 2018; 81:51-62. [PMID: 30910088 DOI: 10.1016/j.fm.2018.03.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 03/16/2018] [Accepted: 03/29/2018] [Indexed: 11/19/2022]
Abstract
Fungal spoilage of products manufactured by the food and beverage industry imposes significant annual global revenue losses. Mould spoilage can also be a food safety issue due to the production of mycotoxins by these moulds. To prevent mould spoilage, it is essential that the associated mycobiota be adequately isolated and accurately identified. The main fungal groups associated with spoilage are the xerophilic, heat-resistant, preservative-resistant, anaerobic and psychrophilic fungi. To assess mould spoilage, the appropriate methodology and media must be used. While classic mycological detection methods can detect a broad range of fungi using well validated protocols, they are time consuming and results can take days or even weeks. New molecular detection methods are faster but require good DNA isolation techniques, expensive equipment and may detect viable and non-viable fungi that probably will not spoil a specific product. Although there is no complete and easy method for the detection of fungi in food it is important to be aware of the limitation of the methodology. More research is needed on the development of methods of detection and identification that are both faster and highly sensitive.
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Affiliation(s)
- Emilia Rico-Munoz
- BCN Research Laboratories, Inc., 2491 Stock Creek Blvd., Rockford, TN 37853, USA.
| | - Robert A Samson
- Westerdijk Fungal Biodiversity Institute, Dept. Applied and Industrial Mycology, Uppsalalaan 8, Utrecht, CT 3584, The Netherlands
| | - Jos Houbraken
- Westerdijk Fungal Biodiversity Institute, Dept. Applied and Industrial Mycology, Uppsalalaan 8, Utrecht, CT 3584, The Netherlands
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The Aspergillus flavus Homeobox Gene, hbx1, is Required for Development and Aflatoxin Production. Toxins (Basel) 2017; 9:toxins9100315. [PMID: 29023405 PMCID: PMC5666362 DOI: 10.3390/toxins9100315] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/06/2017] [Accepted: 10/09/2017] [Indexed: 11/17/2022] Open
Abstract
Homeobox proteins, a class of well conserved transcription factors, regulate the expression of targeted genes, especially those involved in development. In filamentous fungi, homeobox genes are required for normal conidiogenesis and fruiting body formation. In the present study, we identified eight homeobox (hbx) genes in the aflatoxin-producing ascomycete, Aspergillus flavus, and determined their respective role in growth, conidiation and sclerotial production. Disruption of seven of the eight genes had little to no effect on fungal growth and development. However, disruption of the homeobox gene AFLA_069100, designated as hbx1, in two morphologically different A. flavus strains, CA14 and AF70, resulted in complete loss of production of conidia and sclerotia as well as aflatoxins B1 and B2, cyclopiazonic acid and aflatrem. Microscopic examination showed that the Δhbx1 mutants did not produce conidiophores. The inability of Δhbx1 mutants to produce conidia was related to downregulation of brlA (bristle) and abaA (abacus), regulatory genes for conidiophore development. These mutants also had significant downregulation of the aflatoxin pathway biosynthetic genes aflC, aflD, aflM and the cluster-specific regulatory gene, aflR. Our results demonstrate that hbx1 not only plays a significant role in controlling A. flavus development but is also critical for the production of secondary metabolites, such as aflatoxins.
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Norton TS, Al Abdallah Q, Hill AM, Lovingood RV, Fortwendel JR. The Aspergillus fumigatus farnesyltransferase β-subunit, RamA, mediates growth, virulence, and antifungal susceptibility. Virulence 2017; 8:1401-1416. [PMID: 28489963 PMCID: PMC5711395 DOI: 10.1080/21505594.2017.1328343] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Post-translational prenylation mechanisms, including farnesylation and geranylgeranylation, mediate both subcellular localization and protein-protein interaction in eukaryotes. The prenyltransferase complex is an αβ heterodimer in which the essential α-subunit is common to both the farnesyltransferase and the geranylgeranyltransferase type-I enzymes. The β-subunit is unique to each enzyme. Farnesyltransferase activity is an important mediator of protein localization and subsequent signaling for multiple proteins, including Ras GTPases. Here, we examined the importance of protein farnesylation in the opportunistic fungal pathogen Aspergillus fumigatus through generation of a mutant lacking the farnesyltransferase β-subunit, ramA. Although farnesyltransferase activity was found to be non-essential in A. fumigatus, diminished hyphal outgrowth, delayed polarization kinetics, decreased conidial viability, and irregular distribution of nuclei during polarized growth were noted upon ramA deletion (ΔramA). Although predicted to be a target of the farnesyltransferase enzyme complex, we found that localization of the major A. fumigatus Ras GTPase protein, RasA, was only partially regulated by farnesyltransferase activity. Furthermore, the farnesyltransferase-deficient mutant exhibited attenuated virulence in a murine model of invasive aspergillosis, characterized by decreased tissue invasion and development of large, swollen hyphae in vivo. However, loss of ramA also led to a Cyp51A/B-independent increase in resistance to triazole antifungal drugs. Our findings indicate that protein farnesylation underpins multiple cellular processes in A. fumigatus, likely due to the large body of proteins affected by ramA deletion.
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Affiliation(s)
- Tiffany S Norton
- a Department of Microbiology and Immunology , University of South Alabama , Mobile , AL , USA
| | - Qusai Al Abdallah
- b Department of Clinical Pharmacy , University of Tennessee Health Science Center , Memphis , TN , USA
| | - Amy M Hill
- a Department of Microbiology and Immunology , University of South Alabama , Mobile , AL , USA
| | - Rachel V Lovingood
- a Department of Microbiology and Immunology , University of South Alabama , Mobile , AL , USA
| | - Jarrod R Fortwendel
- b Department of Clinical Pharmacy , University of Tennessee Health Science Center , Memphis , TN , USA
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Leiter É, Park HS, Kwon NJ, Han KH, Emri T, Oláh V, Mészáros I, Dienes B, Vincze J, Csernoch L, Yu JH, Pócsi I. Characterization of the aodA, dnmA, mnSOD and pimA genes in Aspergillus nidulans. Sci Rep 2016; 6:20523. [PMID: 26846452 PMCID: PMC4742808 DOI: 10.1038/srep20523] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 01/05/2016] [Indexed: 01/02/2023] Open
Abstract
Mitochondria play key roles in cellular energy generation and lifespan of most eukaryotes. To understand the functions of four nuclear-encoded genes predicted to be related to the maintenance of mitochondrial morphology and function in Aspergillus nidulans, systematic characterization was carried out. The deletion and overexpression mutants of aodA, dnmA, mnSOD and pimA encoding alternative oxidase, dynamin related protein, manganese superoxide dismutase and Lon protease, respectively, were generated and examined for their growth, stress tolerances, respiration, autolysis, cell death, sterigmatocystin production, hyphal morphology and size, and mitochondrial superoxide production as well as development. Overall, genetic manipulation of these genes had less effect on cellular physiology and ageing in A. nidulans than that of their homologs in another fungus Podospora anserina with a well-characterized senescence. The observed interspecial phenotypic differences can be explained by the dissimilar intrinsic stabilities of the mitochondrial genomes in A. nidulans and P. anserina. Furthermore, the marginally altered phenotypes observed in A. nidulans mutants indicate the presence of effective compensatory mechanisms for the complex networks of mitochondrial defense and quality control. Importantly, these findings can be useful for developing novel platforms for heterologous protein production, or on new biocontrol and bioremediation technologies based on Aspergillus species.
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Affiliation(s)
- Éva Leiter
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Hee-Soo Park
- Departments of Bacteriology and Genetics, The University of Wisconsin-Madison, Wisconsin, USA
| | - Nak-Jung Kwon
- Departments of Bacteriology and Genetics, The University of Wisconsin-Madison, Wisconsin, USA
| | - Kap-Hoon Han
- Departments of Bacteriology and Genetics, The University of Wisconsin-Madison, Wisconsin, USA.,Department of Pharmaceutical Engineering, Woosuk University, Wanju, Republic of Korea
| | - Tamás Emri
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Viktor Oláh
- Department of Botany, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Ilona Mészáros
- Department of Botany, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Beatrix Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - János Vincze
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - László Csernoch
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Jae-Hyuk Yu
- Departments of Bacteriology and Genetics, The University of Wisconsin-Madison, Wisconsin, USA
| | - István Pócsi
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
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Runa F, Carbone I, Bhatnagar D, Payne GA. Nuclear heterogeneity in conidial populations of Aspergillus flavus. Fungal Genet Biol 2015; 84:62-72. [PMID: 26362651 DOI: 10.1016/j.fgb.2015.09.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 08/30/2015] [Accepted: 09/08/2015] [Indexed: 10/23/2022]
Abstract
Aspergillus flavus is a major producer of aflatoxin and an opportunistic pathogen for a wide range of hosts. Understanding genotypic and phenotypic variation within strains of A. flavus is important for controlling disease and reducing aflatoxin contamination. A. flavus is multinucleate and predominantly haploid (n) and homokaryotic. Although cryptic heterokaryosis may occur in nature, it is unclear how nuclei in A. flavus influence genetic heterogeneity and if nuclear condition plays a role in fungal ecology. A. flavus mainly reproduces asexually by producing conidia. In order to observe whether conidia are homokaryotic or heterokaryotic, we labeled nuclei of A. flavus using two different nuclear localized fluorescent reporters. The reporter constructs (pYH2A and pCH2B), encode histones HH2A and HH2B fused at the C terminus with either yellow (EYFP) or cyan (ECFP) fluorescent proteins, respectively. The constructs were transformed into the double auxotrophic strain AFC-1 (-pyrG, -argD) to generate a strain containing each reporter construct. By taking advantage of the nutritional requirement for each strain, we were able to generate fusants between FR36 (-argD) expressing yellow fluorescence, and FR46 (-pyr4) expressing cyan fluorescence. Conidia from fusants between FR36 and FR46 showed three types of fluorescence: only EYFP, only ECFP or both EYFP+ECFP. Conidia containing nuclei expressing EYFP+ECFP were separated by Fluorescence-Activated Cell sorting (FACS) and were found to contain both yellow and cyan fluorescent markers in the same nucleus. Further characterization of conidia having only one nucleus but expressing both EYFP+ECFP fluorescence were found to be diploid (2n). Our findings suggest that A. flavus maintains nuclear heterogeneity in conidial populations.
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Affiliation(s)
- Farhana Runa
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, NC, USA.
| | - Ignazio Carbone
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, NC, USA
| | | | - Gary A Payne
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, NC, USA
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Abstract
Koji mold, Aspergillus oryzae, has been used for the production of sake, miso, and soy sauce for more than one thousand years in Japan. Due to the importance, A. oryzae has been designated as the national micro-organism of Japan (Koku-kin). A. oryzae has been intensively studied in the past century, with most investigations focusing on breeding techniques and developing methods for Koji making for sake brewing. However, the understanding of fundamental biology of A. oryzae remains relatively limited compared with the yeast Saccharomyces cerevisiae. Therefore, we have focused on studying the cell biology including live cell imaging of organelles, protein vesicular trafficking, autophagy, and Woronin body functions using the available genomic information. In this review, I describe essential findings of cell biology of A. oryzae obtained in our study for a quarter of century. Understanding of the basic biology will be critical for not its biotechnological application, but also for an understanding of the fundamental biology of other filamentous fungi.
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Affiliation(s)
- Katsuhiko Kitamoto
- a Department of Biotechnology , The University of Tokyo , 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657
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11
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Ji Y, Xu Y, Li Y, Tu Z, Huang Z, Liu X, Lei D. Application of membrane filtration method to isolate uninuclei conidium in Aspergillus oryzae transformation system based on the pyrG marker. Food Sci Biotechnol 2013. [DOI: 10.1007/s10068-013-0013-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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12
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Deak E, Nelson M, Hernández-Rodríguez Y, Gade L, Baddley J, Momany M, Steele C, Balajee SA. Aspergillus terreus accessory conidia are multinucleated, hyperpolarizing structures that display differential dectin staining and can induce heightened inflammatory responses in a pulmonary model of aspergillosis. Virulence 2011; 2:200-7. [PMID: 21543882 DOI: 10.4161/viru.2.3.15799] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In addition to phialidic conidia (PC), A. terreus produces accessory conidia (AC) both in vitro and in vivo. AC are distinct from PC in cell surface architecture, with the AC surfaces displaying more β-glucan, a molecule that can be a trigger for the induction of inflammatory responses. The present study follows β-glucan cell surface presentation throughout the course of germination of both types of conidia, and analyzes the differential capacity of AC and PC to elicit immune responses. Results show that AC display early, increased dectin-1 labeling on their cell surfaces compared to PC, and this differential dectin-1 labeling is sustained on the cell surface from the time of breaking dormancy through early germ tube emergence. Mouse alveolar macrophages showed a stronger inflammatory cytokine/chemokine response when challenged with AC than with PC in both ex vivo and in vivo experiments, correlating with the greater exposure of β-glucan exhibited by AC. Further, histopathologic staining of the lungs from mice challenged with AC demonstrated heightened cell recruitment and increased inflammatory response compared to the lungs of mice challenged with PC. Our study also demonstrates that AC are multinucleate structures with the ability to germinate rapidly, polarizing in multiple directions and producing several hyphal extensions. We present evidence that A. terreus AC are phenotypically distinct from PC and can be potent activators of the innate immune mechanism thus possibly playing a role in this organism's pathogenesis.
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Affiliation(s)
- Eszter Deak
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Morphological characteristics of sporangiospores of the tempe fungus Rhizopus oligosporus differentiate it from other taxa of the R. microsporus group. ACTA ACUST UNITED AC 2007; 112:547-63. [PMID: 18400482 DOI: 10.1016/j.mycres.2007.11.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Revised: 10/16/2007] [Accepted: 11/21/2007] [Indexed: 11/20/2022]
Abstract
The fungus Rhizopus oligosporus (R. microsporus var. oligosporus) is traditionally used to make tempe, a fermented food based on soybeans. Interest in the fungus has steadily increased, as it can also ferment other substrates, produce enzymes, and treat waste material. R. oligosporus belongs to the R. microsporus group consisting of morphologically similar taxa, which are associated with food fermentation, pathogenesis, or unwanted metabolite production (rhizonins and rhizoxins). The ornamentation pattern, shape, and size of sporangiospores of 26 R. microsporus group strains and two R. oryzae strains were studied using low-temperature SEM (LT-SEM) and LM. This study has shown that: (1) LT-SEM generates images from well-conserved sporangiophores, sporangia, and spores. (2) Robust spore ornamentation patterns can be linked to all different taxa of the R. microsporus group, some previously incorrectly characterized as smooth. Ornamentation included valleys and ridges running in parallel, granular plateaus, or smooth polar areas. Distribution of ornamentation patterns was related to spore shape, which either was regular, ranging from globose to ellipsoidal, or irregular. Specific differences in spore shape, size, and ornamentation were observed between Rhizopus taxa, and sometimes between strains. (3) R. oligosporus has a defect in the spore formation process, which may be related to the domesticated nature of this taxon. It had a high proportion, 10-31%, of large and irregular spores, and was significantly differentiated from other, natural Rhizopus taxa as evaluated with partial least squares discriminant analysis. It is remarkable that the vehicle of distribution, the sporangiospore, is affected in the strains that are distributed by human activity. This provides information about the specificity and speed of changes that occur in fungal strains because of their use in (food) industry.
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Masai K, Maruyama JI, Sakamoto K, Nakajima H, Akita O, Kitamoto K. Square-plate culture method allows detection of differential gene expression and screening of novel, region-specific genes in Aspergillus oryzae. Appl Microbiol Biotechnol 2006; 71:881-91. [PMID: 16708193 DOI: 10.1007/s00253-006-0429-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2006] [Revised: 03/08/2006] [Accepted: 03/15/2006] [Indexed: 11/26/2022]
Abstract
When grown on solid agar medium, the mycelium of a filamentous fungus, Aspergillus oryzae, forms three morphologically distinct regions: the tip (T), white (W), and basal (B) regions. In this study, we developed the square-plate culture method, a novel culture method that enabled the extraction of mRNA samples from the three regions and analyzed the differential gene expression of the A. oryzae mycelium in concert with the microarray technique. Expression of genes involved in protein synthesis was predominant in the T region; relative expression was, at most, six times higher in the T region compared to the other regions. Genes encoding hypothetical proteins were expressed at high levels in the W and B regions. In addition, genes coding transporters/permeases were predominantly transcribed in the B region. By analyzing the expression patterns of genes in the three regions, we demonstrated the dynamic changes in the regulation of gene expression that occur along the mycelium of filamentous fungi. Consequently, our study established a method to analyze and screen for region-specific genes whose function may be essential for morphogenesis and differentiation in filamentous fungi and whose traits may be beneficial to the biotechnology industry.
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Affiliation(s)
- Kumiko Masai
- Graduate School of Agricultural and Life Sciences, Department of Biotechnology, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
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15
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Shoji JY, Arioka M, Kitamoto K. Vacuolar membrane dynamics in the filamentous fungus Aspergillus oryzae. EUKARYOTIC CELL 2006; 5:411-21. [PMID: 16467481 PMCID: PMC1405889 DOI: 10.1128/ec.5.2.411-421.2006] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Accepted: 10/18/2005] [Indexed: 11/20/2022]
Abstract
Vacuoles in filamentous fungi are highly pleomorphic and some of them, e.g., tubular vacuoles, are implicated in intra- and intercellular transport. In this report, we isolated Aovam3, the homologue of the Saccharomyces cerevisiae VAM3 gene that encodes the vacuolar syntaxin, from Aspergillus oryzae. In yeast complementation analyses, the expression of Aovam3 restored the phenotypes of both Deltavam3 and Deltapep12 mutants, suggesting that AoVam3p is likely the vacuolar and/or endosomal syntaxin in A. oryzae. FM4-64 [N-(3-triethylammoniumpropyl)-4-(p-diethylaminophenyl-hexatrienyl)pyridinium dibromide] and CMAC (7-amino-4-chloromethylcoumarin) staining confirmed that the fusion protein of enhanced green fluorescent protein (EGFP) with AoVam3p (EGFP-AoVam3p) localized on the membrane of the pleomorphic vacuolar networks, including large spherical vacuoles, tubular vacuoles, and putative late endosomes/prevacuolar compartments. EGFP-AoVam3p-expressing strains allowed us to observe the dynamics of vacuoles with high resolutions, and moreover, led to the discovery of several new aspects of fungal vacuoles, which have not been discovered so far with conventional staining methods, during different developmental stages. In old hyphae, EGFP fluorescence was present in the entire lumen of large vacuoles, which occupied most of the cell, indicating that degradation of cytosolic materials had occurred in such hyphae via an autophagic process. In hyphae that were not in contact with nutrients, such as aerial hyphae and hyphae that grew on a glass surface, vacuoles were composed of small punctate structures and tubular elements that often formed reticulum-like networks. These observations imply the presence of so-far-unrecognized roles of vacuoles in the development of filamentous fungi.
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Affiliation(s)
- Jun-ya Shoji
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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16
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Seshime Y, Juvvadi PR, Fujii I, Kitamoto K. Genomic evidences for the existence of a phenylpropanoid metabolic pathway in Aspergillus oryzae. Biochem Biophys Res Commun 2005; 337:747-51. [PMID: 16182237 DOI: 10.1016/j.bbrc.2005.08.233] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Accepted: 08/29/2005] [Indexed: 10/25/2022]
Abstract
Plants interact with their environment by producing a diverse array of secondary metabolites. A majority of these compounds are phenylpropanoids and flavonoids which are valued for their medicinal and agricultural properties. The phenylpropanoid biosynthesis pathway proceeds with the basic C6-C3 carbon skeleton of phenylalanine, and involves a wide range of enzymes viz., phenylalanine ammonia lyase, coumarate hydroxylase, coumarate ligase, chalcone synthase, chalcone reductase and chalcone isomerase. Recently, bacteria have also been shown to contain homodimeric polyketide synthases belonging to the plant chalcone synthase superfamily linking the capabilities of plants and bacteria in the biosynthesis of flavonoids. We report here the presence of genes encoding the core enzymes of the phenylpropanoid pathway in an industrially useful fungus, Aspergillus oryzae. Although the assignment of enzyme function must be confirmed by further biochemical evidences, this work has allowed us to anticipate the phenylpropanoid metabolism profile in a filamentous fungus for the first time and paves way for research on identifying novel fungal flavonoid-like metabolites.
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Affiliation(s)
- Yasuyo Seshime
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan
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