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Wang X, Jarmusch SA, Frisvad JC, Larsen TO. Current status of secondary metabolite pathways linked to their related biosynthetic gene clusters in Aspergillus section Nigri. Nat Prod Rep 2023; 40:237-274. [PMID: 35587705 DOI: 10.1039/d1np00074h] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Covering: up to the end of 2021Aspergilli are biosynthetically 'talented' micro-organisms and therefore the natural products community has continually been interested in the wealth of biosynthetic gene clusters (BGCs) encoding numerous secondary metabolites related to these fungi. With the rapid increase in sequenced fungal genomes combined with the continuous development of bioinformatics tools such as antiSMASH, linking new structures to unknown BGCs has become much easier when taking retro-biosynthetic considerations into account. On the other hand, in most cases it is not as straightforward to prove proposed biosynthetic pathways due to the lack of implemented genetic tools in a given fungal species. As a result, very few secondary metabolite biosynthetic pathways have been characterized even amongst some of the most well studied Aspergillus spp., section Nigri (black aspergilli). This review will cover all known biosynthetic compound families and their structural diversity known from black aspergilli. We have logically divided this into sub-sections describing major biosynthetic classes (polyketides, non-ribosomal peptides, terpenoids, meroterpenoids and hybrid biosynthesis). Importantly, we will focus the review on metabolites which have been firmly linked to their corresponding BGCs.
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Affiliation(s)
- Xinhui Wang
- DTU Bioengineering, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
| | - Scott A Jarmusch
- DTU Bioengineering, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
| | - Jens C Frisvad
- DTU Bioengineering, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
| | - Thomas O Larsen
- DTU Bioengineering, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
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Seekles SJ, Punt M, Savelkoel N, Houbraken J, Wösten HAB, Ohm RA, Ram AFJ. Genome sequences of 24 Aspergillus niger sensu stricto strains to study strain diversity, heterokaryon compatibility, and sexual reproduction. G3 (BETHESDA, MD.) 2022; 12:jkac124. [PMID: 35608315 PMCID: PMC9258588 DOI: 10.1093/g3journal/jkac124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 05/10/2022] [Indexed: 12/02/2022]
Abstract
Mating-type distribution within a phylogenetic tree, heterokaryon compatibility, and subsequent diploid formation were studied in 24 Aspergillus niger sensu stricto strains. The genomes of the 24 strains were sequenced and analyzed revealing an average of 6.1 ± 2.0 variants/kb between Aspergillus niger sensu stricto strains. The genome sequences were used together with available genome data to generate a phylogenetic tree revealing 3 distinct clades within Aspergillus niger sensu stricto. The phylogenetic tree revealed that both MAT1-1 and MAT1-2 mating types were present in each of the 3 clades. The phylogenetic differences were used to select for strains to analyze heterokaryon compatibility. Conidial color markers (fwnA and brnA) and auxotrophic markers (pyrG and nicB) were introduced via CRISPR/Cas9-based genome editing in a selection of strains. Twenty-three parasexual crosses using 11 different strains were performed. Only a single parasexual cross between genetically highly similar strains resulted in a successful formation of heterokaryotic mycelium and subsequent diploid formation, indicating widespread heterokaryon incompatibility as well as multiple active heterokaryon incompatibility systems between Aspergillus niger sensu stricto strains. The 2 vegetatively compatible strains were of 2 different mating types and a stable diploid was isolated from this heterokaryon. Sclerotium formation was induced on agar media containing Triton X-100; however, the sclerotia remained sterile and no ascospores were observed. Nevertheless, this is the first report of a diploid Aspergillus niger sensu stricto strain with 2 different mating types, which offers the unique possibility to screen for conditions that might lead to ascospore formation in A. niger.
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Affiliation(s)
- Sjoerd J Seekles
- TIFN, 6708 PW, Wageningen, the Netherlands
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, 2333 BE, Leiden, the Netherlands
| | - Maarten Punt
- TIFN, 6708 PW, Wageningen, the Netherlands
- Microbiology, Department of Biology, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Niki Savelkoel
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, 2333 BE, Leiden, the Netherlands
| | - Jos Houbraken
- TIFN, 6708 PW, Wageningen, the Netherlands
- Applied & Industrial Mycology, Westerdijk Fungal Biodiversity Institute, 3584 CT, Utrecht, the Netherlands
| | - Han A B Wösten
- TIFN, 6708 PW, Wageningen, the Netherlands
- Microbiology, Department of Biology, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Robin A Ohm
- TIFN, 6708 PW, Wageningen, the Netherlands
- Microbiology, Department of Biology, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Arthur F J Ram
- TIFN, 6708 PW, Wageningen, the Netherlands
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, 2333 BE, Leiden, the Netherlands
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Polyphasic Characterization of Four Aspergillus Species as Potential Biocontrol Agents for White Mold Disease of Bean. J Fungi (Basel) 2022; 8:jof8060626. [PMID: 35736109 PMCID: PMC9224856 DOI: 10.3390/jof8060626] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/22/2022] [Accepted: 05/26/2022] [Indexed: 11/17/2022] Open
Abstract
The genus Aspergillus comprises several species that play pivotal roles in agriculture. Herein, we morphologically and physiologically characterized four genetically distinct Aspergillus spp., namely A. japonicus, A. niger, A. flavus, and A. pseudoelegans, and examined their ability to suppress the white mold disease of bean caused by Sclerotinia sclerotiorum in vitro and under greenhouse conditions. Seriation type of Aspergillus spp. correlates with conidiospores discharge as detected on the Petri glass lid. Members of Nigri section cover their conidial heads with hard shells after prolonged incubation. In addition, sporulation of the tested Aspergillus isolates is temperature sensitive as it becomes inhibited at low temperatures and the colonies become white. Examined Aspergillus spp. were neither infectious to legumes nor aflatoxigenic as confirmed by HPLC except for A. flavus and A. pseudoelegans which, secreted 5 and 1 ppm of aflatoxin B1, respectively. Co-inoculations of Sclerotinia’s mycelium or sclerotia with a spore suspension of Aspergillus spp. inhibited their germination on PDA at 18 °C and 28 °C, and halted disease onset on detached common bean and soybean leaves. Similarly, plants treated with A. japonicus and A. niger showed the highest survival rates compared to untreated plants. In conclusion, black Aspergillus spp. are efficient biocides and safe alternatives for the management of plant diseases, particularly in organic farms.
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Beyond the Biosynthetic Gene Cluster Paradigm: Genome-Wide Coexpression Networks Connect Clustered and Unclustered Transcription Factors to Secondary Metabolic Pathways. Microbiol Spectr 2021; 9:e0089821. [PMID: 34523946 PMCID: PMC8557879 DOI: 10.1128/spectrum.00898-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Fungal secondary metabolites are widely used as therapeutics and are vital components of drug discovery programs. A major challenge hindering discovery of novel secondary metabolites is that the underlying pathways involved in their biosynthesis are transcriptionally silent under typical laboratory growth conditions, making it difficult to identify the transcriptional networks that they are embedded in. Furthermore, while the genes participating in secondary metabolic pathways are typically found in contiguous clusters on the genome, known as biosynthetic gene clusters (BGCs), this is not always the case, especially for global and pathway-specific regulators of pathways’ activities. To address these challenges, we used 283 genome-wide gene expression data sets of the ascomycete cell factory Aspergillus niger generated during growth under 155 different conditions to construct two gene coexpression networks based on Spearman’s correlation coefficients (SCCs) and on mutual rank-transformed Pearson’s correlation coefficients (MR-PCCs). By mining these networks, we predicted six transcription factors, named MjkA to MjkF, to regulate secondary metabolism in A. niger. Overexpression of each transcription factor using the Tet-On cassette modulated the production of multiple secondary metabolites. We found that the SCC and MR-PCC approaches complemented each other, enabling the delineation of putative global (SCC) and pathway-specific (MR-PCC) transcription factors. These results highlight the potential of coexpression network approaches to identify and activate fungal secondary metabolic pathways and their products. More broadly, we argue that drug discovery programs in fungi should move beyond the BGC paradigm and focus on understanding the global regulatory networks in which secondary metabolic pathways are embedded. IMPORTANCE There is an urgent need for novel bioactive molecules in both agriculture and medicine. The genomes of fungi are thought to contain vast numbers of metabolic pathways involved in the biosynthesis of secondary metabolites with diverse bioactivities. Because these metabolites are biosynthesized only under specific conditions, the vast majority of the fungal pharmacopeia awaits discovery. To discover the genetic networks that regulate the activity of secondary metabolites, we examined the genome-wide profiles of gene activity of the cell factory Aspergillus niger across hundreds of conditions. By constructing global networks that link genes with similar activities across conditions, we identified six putative global and pathway-specific regulators of secondary metabolite biosynthesis. Our study shows that elucidating the behavior of the genetic networks of fungi under diverse conditions harbors enormous promise for understanding fungal secondary metabolism, which ultimately may lead to novel drug candidates.
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Díaz GV, Coniglio RO, Chungara CI, Zapata PD, Villalba LL, Fonseca MI. Aspergillus niger LBM 134 isolated from rotten wood and its potential cellulolytic ability. Mycology 2021; 12:160-173. [PMID: 34567828 PMCID: PMC8462884 DOI: 10.1080/21501203.2020.1823509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Aspergillus is a genus of filamentous and cosmopolitan fungi that includes important species for medical mycology, food, basic research and agro-industry areas. Aspergillus section Nigri are efficient producers of hydrolytic enzymes such as cellulases that are employed in the cellulose conversion. Hence, the search of new cellulolytic isolates and their correct identification is important for carrying out safe biotechnological processes. This study aimed to characterise the cellulolytic potential of Aspergillus sp. LBM 134, isolated from the Paranaense rainforest (Argentina) and to identify the isolate through a polyphasic approach. The fungus was identified as Aspergillus niger and its cellulolytic potential was evaluated by using Congo red technique and fluorescence plate assays for carboxymethyl cellulase, β-glucosidase and cellobiohydrolase, respectively. All three cellulase activities were positive; this bio-prospective positioned A. niger LBM 134 as a promising alternative for industries that require organisms capable of carrying out cellulosic biomass processing.
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Affiliation(s)
- Gabriela Verónica Díaz
- Laboratorio de Biotecnología Molecular, Instituto de Biotecnología Misiones "María Ebe Reca" CONICET. Facultad de Ciencias Exactas, Químicas y Naturales. Universidad Nacional de Misiones. Ruta, Posadas, Misiones, Argentina
| | - Romina Olga Coniglio
- Laboratorio de Biotecnología Molecular, Instituto de Biotecnología Misiones "María Ebe Reca" CONICET. Facultad de Ciencias Exactas, Químicas y Naturales. Universidad Nacional de Misiones. Ruta, Posadas, Misiones, Argentina
| | - Clara Inés Chungara
- Laboratorio de Biotecnología Molecular, Instituto de Biotecnología Misiones "María Ebe Reca" CONICET. Facultad de Ciencias Exactas, Químicas y Naturales. Universidad Nacional de Misiones. Ruta, Posadas, Misiones, Argentina
| | - Pedro Darío Zapata
- Laboratorio de Biotecnología Molecular, Instituto de Biotecnología Misiones "María Ebe Reca" CONICET. Facultad de Ciencias Exactas, Químicas y Naturales. Universidad Nacional de Misiones. Ruta, Posadas, Misiones, Argentina
| | - Laura Lidia Villalba
- Laboratorio de Biotecnología Molecular, Instituto de Biotecnología Misiones "María Ebe Reca" CONICET. Facultad de Ciencias Exactas, Químicas y Naturales. Universidad Nacional de Misiones. Ruta, Posadas, Misiones, Argentina
| | - María Isabel Fonseca
- Laboratorio de Biotecnología Molecular, Instituto de Biotecnología Misiones "María Ebe Reca" CONICET. Facultad de Ciencias Exactas, Químicas y Naturales. Universidad Nacional de Misiones. Ruta, Posadas, Misiones, Argentina
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Genome sequencing of the neotype strain CBS 554.65 reveals the MAT1-2 locus of Aspergillus niger. BMC Genomics 2021; 22:679. [PMID: 34548025 PMCID: PMC8454179 DOI: 10.1186/s12864-021-07990-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 09/03/2021] [Indexed: 12/05/2022] Open
Abstract
Background Aspergillus niger is a ubiquitous filamentous fungus widely employed as a cell factory thanks to its abilities to produce a wide range of organic acids and enzymes. Its genome was one of the first Aspergillus genomes to be sequenced in 2007, due to its economic importance and its role as model organism to study fungal fermentation. Nowadays, the genome sequences of more than 20 A. niger strains are available. These, however, do not include the neotype strain CBS 554.65. Results The genome of CBS 554.65 was sequenced with PacBio. A high-quality nuclear genome sequence consisting of 17 contigs with a N50 value of 4.07 Mbp was obtained. The assembly covered all the 8 centromeric regions of the chromosomes. In addition, a complete circular mitochondrial DNA assembly was obtained. Bioinformatic analyses revealed the presence of a MAT1-2-1 gene in this genome, contrary to the most commonly used A. niger strains, such as ATCC 1015 and CBS 513.88, which contain a MAT1-1-1 gene. A nucleotide alignment showed a different orientation of the MAT1–1 locus of ATCC 1015 compared to the MAT1–2 locus of CBS 554.65, relative to conserved genes flanking the MAT locus. Within 24 newly sequenced isolates of A. niger half of them had a MAT1–1 locus and the other half a MAT1–2 locus. The genomic organization of the MAT1–2 locus in CBS 554.65 is similar to other Aspergillus species. In contrast, the region comprising the MAT1–1 locus is flipped in all sequenced strains of A. niger. Conclusions This study, besides providing a high-quality genome sequence of an important A. niger strain, suggests the occurrence of genetic flipping or switching events at the MAT1–1 locus of A. niger. These results provide new insights in the mating system of A. niger and could contribute to the investigation and potential discovery of sexuality in this species long thought to be asexual. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07990-8.
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Khuna S, Suwannarach N, Kumla J, Frisvad JC, Matsui K, Nuangmek W, Lumyong S. Growth Enhancement of Arabidopsis ( Arabidopsis thaliana) and Onion ( Allium cepa) With Inoculation of Three Newly Identified Mineral-Solubilizing Fungi in the Genus Aspergillus Section Nigri. Front Microbiol 2021; 12:705896. [PMID: 34456888 PMCID: PMC8397495 DOI: 10.3389/fmicb.2021.705896] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/12/2021] [Indexed: 11/13/2022] Open
Abstract
Some soil fungi play an important role in supplying elements to plants by the solubilizing of insoluble minerals in the soil. The present study was conducted to isolate the mineral-solubilizing fungi from rhizosphere soil in some agricultural areas in northern Thailand. Seven fungal strains were obtained and identified using a polyphasic taxonomic approach with multilocus phylogenetic and phenotypic (morphology and extrolite profile) analyses. All obtained fungal strains were newly identified in the genus Aspergillus section Nigri, Aspergillus chiangmaiensis (SDBR-CMUI4 and SDBR-CMU15), Aspergillus pseudopiperis (SDBR-CMUI1 and SDBR-CMUI7), and Aspergillus pseudotubingensis (SDBR-CMUO2, SDBR-CMUO8, and SDBR-CMU20). All fungal strains were able to solubilize the insoluble mineral form of calcium, copper, cobalt, iron, manganese, magnesium, zinc, phosphorus, feldspar, and kaolin in the agar plate assay. Consequently, the highest phosphate solubilization strains (SDBR-CMUI1, SDBR-CMUI4, and SDBR-CMUO2) of each fungal species were selected for evaluation of their plant growth enhancement ability on Arabidopsis and onion in laboratory and greenhouse experiments, respectively. Plant disease symptoms were not found in any treatment of fungal inoculation and control. All selected fungal strains significantly increased the leaf number, leaf length, dried biomass of shoot and root, chlorophyll content, and cellular inorganic phosphate content in both Arabidopsis and onion plants under supplementation with insoluble mineral phosphate. Additionally, the inoculation of selected fungal strains also improved the yield and quercetin content of onion bulb. Thus, the selected strains reveal the potential in plant growth promotion agents that can be applied as a biofertilizer in the future.
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Affiliation(s)
- Surapong Khuna
- Research Center of Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.,Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
| | - Nakarin Suwannarach
- Research Center of Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.,Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
| | - Jaturong Kumla
- Research Center of Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.,Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
| | - Jens Christian Frisvad
- Department of Biotechnology and Biomedicine, DTU-Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Kenji Matsui
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
| | - Wipornpan Nuangmek
- Faculty of Agriculture and Natural Resources, University of Phayao, Phayao, Thailand
| | - Saisamorn Lumyong
- Research Center of Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.,Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.,Academy of Science, The Royal Society of Thailand, Bangkok, Thailand
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Berestetskiy A, Hu Q. The Chemical Ecology Approach to Reveal Fungal Metabolites for Arthropod Pest Management. Microorganisms 2021; 9:1379. [PMID: 34202923 PMCID: PMC8307166 DOI: 10.3390/microorganisms9071379] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/16/2021] [Accepted: 06/22/2021] [Indexed: 12/13/2022] Open
Abstract
Biorational insecticides (for instance, avermectins, spinosins, azadirachtin, and afidopyropen) of natural origin are increasingly being used in agriculture. The review considers the chemical ecology approach for the search for new compounds with insecticidal properties (entomotoxic, antifeedant, and hormonal) produced by fungi of various ecological groups (entomopathogens, soil saprotrophs, endophytes, phytopathogens, and mushrooms). The literature survey revealed that insecticidal metabolites of entomopathogenic fungi have not been sufficiently studied, and most of the well-characterized compounds show moderate insecticidal activity. The greatest number of substances with insecticidal properties was found to be produced by soil fungi, mainly from the genera Aspergillus and Penicillium. Metabolites with insecticidal and antifeedant properties were also found in endophytic and phytopathogenic fungi. It was noted that insect pests of stored products are mostly low sensitive to mycotoxins. Mushrooms were found to be promising producers of antifeedant compounds as well as insecticidal proteins. The expansion of the number of substances with insecticidal properties detected in prospective fungal species is possible by mining fungal genomes for secondary metabolite gene clusters and secreted proteins with their subsequent activation by various methods. The efficacy of these studies can be increased with high-throughput techniques of extraction of fungal metabolites and their analysis by various methods of chromatography and mass spectrometry.
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Affiliation(s)
| | - Qiongbo Hu
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China;
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Ellena V, Bucchieri D, Arcalis E, Sauer M, Steiger MG. Sclerotia formed by citric acid producing strains of Aspergillus niger: Induction and morphological analysis. Fungal Biol 2021; 125:485-494. [PMID: 34024596 DOI: 10.1016/j.funbio.2021.01.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 01/22/2021] [Accepted: 01/25/2021] [Indexed: 02/07/2023]
Abstract
Some strains of Aspergillus niger have been previously reported to produce sclerotia under certain conditions. Sclerotia are aggregations of hyphae which can act either as survival or as sexual structures in species related to A. niger. In this study, we were able to induce the formation of sclerotia in the progenitor of the industrial citric acid producing strains of A. niger, ATCC 1015, and in pyrG mutants derived from it. Sclerotia can be stably formed by ATCC 1015 on malt extract agar medium supplemented with raisins, showing a spatial differentiation of the fungus dependent on the addition and on the position of the fruits into the medium. On other media, including malt extract agar, pyrG auxotrophs also form abundant sclerotia, while the complementation of this gene reverses this phenotype. Additionally, a macro- and microscopical analysis of the sclerotia is reported. Our results show that the sclerotia formed by A. niger are similar to those formed by other fungi, not only in their morphology but also in their ability to germinate and regenerate the organism.
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Affiliation(s)
- Valeria Ellena
- Austrian Centre of Industrial Biotechnology (ACIB GmbH), Muthgasse 18, Vienna, Austria; Institute of Microbiology and Microbial Biotechnology, BOKU-VIBT, University of Natural Resources and Life Sciences, Muthgasse 18, Vienna, Austria; Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria
| | - Daniela Bucchieri
- Institute of Microbiology and Microbial Biotechnology, BOKU-VIBT, University of Natural Resources and Life Sciences, Muthgasse 18, Vienna, Austria
| | - Elsa Arcalis
- Department of Applied Genetics and Cell Biology (DAGZ), University of Natural Resources and Life Sciences, Muthgasse 11, Vienna, Austria
| | - Michael Sauer
- Austrian Centre of Industrial Biotechnology (ACIB GmbH), Muthgasse 18, Vienna, Austria; Institute of Microbiology and Microbial Biotechnology, BOKU-VIBT, University of Natural Resources and Life Sciences, Muthgasse 18, Vienna, Austria; CD Laboratory for Biotechnology of Glycerol, Muthgasse 18, Vienna, Austria
| | - Matthias G Steiger
- Austrian Centre of Industrial Biotechnology (ACIB GmbH), Muthgasse 18, Vienna, Austria; Institute of Microbiology and Microbial Biotechnology, BOKU-VIBT, University of Natural Resources and Life Sciences, Muthgasse 18, Vienna, Austria; Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria.
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Ellena V, Sauer M, Steiger MG. The fungal sexual revolution continues: discovery of sexual development in members of the genus Aspergillus and its consequences. Fungal Biol Biotechnol 2020; 7:17. [PMID: 33357234 PMCID: PMC7761153 DOI: 10.1186/s40694-020-00107-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/15/2020] [Indexed: 12/24/2022] Open
Abstract
Asexuality was considered to be a common feature of a large part of fungi, including those of the genus Aspergillus. However, recent advances and the available genomic and genetic engineering technologies allowed to gather more and more indications of a hidden sexuality in fungi previously considered asexual. In parallel, the acquired knowledge of the most suitable conditions for crossings was shown to be crucial to effectively promote sexual reproduction in the laboratory. These discoveries not only have consequences on our knowledge of the biological processes ongoing in nature, questioning if truly asexual fungal species exist, but they also have important implications on other research areas. For instance, the presence of sexuality in certain fungi can have effects on their pathogenicity or on shaping the ecosystem that they normally colonize. For these reasons, further investigations of the sexual potential of Aspergillus species, such as the industrially important A. niger, will be carried on.
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Affiliation(s)
- Valeria Ellena
- Austrian Centre of Industrial Biotechnology (ACIB GmbH), Muthgasse 18, Vienna, Austria. .,Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria.
| | - Michael Sauer
- Austrian Centre of Industrial Biotechnology (ACIB GmbH), Muthgasse 18, Vienna, Austria.,Institute of Microbiology and Microbial Biotechnology, BOKU-VIBT, University of Natural Resources and Life Sciences, Muthgasse 18, Vienna, Austria.,CD Laboratory for Biotechnology of Glycerol, Muthgasse 18, Vienna, Austria
| | - Matthias G Steiger
- Austrian Centre of Industrial Biotechnology (ACIB GmbH), Muthgasse 18, Vienna, Austria.,Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria
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da Silva JJ, Iamanaka BT, Ferranti LS, Massi FP, Taniwaki MH, Puel O, Lorber S, Frisvad JC, Fungaro MHP. Diversity within Aspergillus niger Clade and Description of a New Species: Aspergillus vinaceus sp. nov. J Fungi (Basel) 2020; 6:jof6040371. [PMID: 33348541 PMCID: PMC7767288 DOI: 10.3390/jof6040371] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/13/2020] [Accepted: 12/14/2020] [Indexed: 11/29/2022] Open
Abstract
Diversity of species within Aspergillus niger clade, currently represented by A. niger sensu stricto and A. welwitshiae, was investigated combining three-locus gene sequences, Random Amplified Polymorphic DNA, secondary metabolites profile and morphology. Firstly, approximately 700 accessions belonging to this clade were investigated using calmodulin gene sequences. Based on these sequences, eight haplotypes were clearly identified as A. niger (n = 247) and 17 as A. welwitschiae (n = 403). However, calmodulin sequences did not provide definitive species identities for six haplotypes. To elucidate the taxonomic position of these haplotypes, two other loci, part of the beta-tubulin gene and part of the RNA polymerase II gene, were sequenced and used to perform an analysis of Genealogical Concordance Phylogenetic Species Recognition. This analysis enabled the recognition of two new phylogenetic species. One of the new phylogenetic species showed morphological and chemical distinguishable features in comparison to the known species A. welwitschiae and A. niger. This species is illustrated and described as Aspergillus vinaceus sp. nov. In contrast to A. niger and A. welwitschiae, A. vinaceus strains produced asperazine, but none of them were found to produce ochratoxin A and/or fumonisins. Sclerotium production on laboratory media, which does not occur in strains of A. niger and A. welwitschiae, and strictly sclerotium-associated secondary metabolites (14-Epi-hydroxy-10,23-dihydro-24,25-dehydroaflavinine; 10,23-Dihydro-24,25-dehydroaflavinine; 10,23-Dihydro-24,25-dehydro-21-oxo-aflavinine) were found in A. vinaceus. The strain type of A. vinaceus sp. nov. is ITAL 47,456 (T) (=IBT 35556).
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Affiliation(s)
- Josué J. da Silva
- Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná 86057-970, Brazil; (J.J.d.S.); (L.S.F.); (F.P.M.)
| | - Beatriz T. Iamanaka
- Centro de Ciência e Qualidade de Alimentos, Instituto de Tecnologia de Alimentos, Campinas, São Paulo 13070-178, Brazil; (B.T.I.); (M.H.T.)
| | - Larissa S. Ferranti
- Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná 86057-970, Brazil; (J.J.d.S.); (L.S.F.); (F.P.M.)
| | - Fernanda P. Massi
- Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná 86057-970, Brazil; (J.J.d.S.); (L.S.F.); (F.P.M.)
| | - Marta H. Taniwaki
- Centro de Ciência e Qualidade de Alimentos, Instituto de Tecnologia de Alimentos, Campinas, São Paulo 13070-178, Brazil; (B.T.I.); (M.H.T.)
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), INRAE, ENVT, INP-Purpan, 31027 Toulouse, France; (O.P.); (S.L.)
| | - Sophie Lorber
- Toxalim (Research Centre in Food Toxicology), INRAE, ENVT, INP-Purpan, 31027 Toulouse, France; (O.P.); (S.L.)
| | - Jens C. Frisvad
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Lyngby, Denmark;
| | - Maria Helena P. Fungaro
- Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná 86057-970, Brazil; (J.J.d.S.); (L.S.F.); (F.P.M.)
- Correspondence: ; Tel.: +55-4399-955-4100
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12
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Uka V, Cary JW, Lebar MD, Puel O, De Saeger S, Diana Di Mavungu J. Chemical repertoire and biosynthetic machinery of the Aspergillus flavus secondary metabolome: A review. Compr Rev Food Sci Food Saf 2020; 19:2797-2842. [PMID: 33337039 DOI: 10.1111/1541-4337.12638] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 12/18/2022]
Abstract
Filamentous fungi represent a rich source of extrolites, including secondary metabolites (SMs) comprising a great variety of astonishing structures and interesting bioactivities. State-of-the-art techniques in genome mining, genetic manipulation, and secondary metabolomics have enabled the scientific community to better elucidate and more deeply appreciate the genetic and biosynthetic chemical arsenal of these microorganisms. Aspergillus flavus is best known as a contaminant of food and feed commodities and a producer of the carcinogenic family of SMs, aflatoxins. This fungus produces many SMs including polyketides, ribosomal and nonribosomal peptides, terpenoids, and other hybrid molecules. This review will discuss the chemical diversity, biosynthetic pathways, and biological/ecological role of A. flavus SMs, as well as their significance concerning food safety and security.
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Affiliation(s)
- Valdet Uka
- Center of Excellence in Mycotoxicology and Public Health, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium.,Division of Pharmacy, Faculty of Medicine, University of Pristina, Pristina, Kosovo
| | - Jeffrey W Cary
- Southern Regional Research Center, USDA-ARS, New Orleans, Louisiana
| | - Matthew D Lebar
- Southern Regional Research Center, USDA-ARS, New Orleans, Louisiana
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), INRAE, ENVT, INP-Purpan, UPS, Université de Toulouse, Toulouse, France
| | - Sarah De Saeger
- Center of Excellence in Mycotoxicology and Public Health, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
| | - José Diana Di Mavungu
- Center of Excellence in Mycotoxicology and Public Health, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
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13
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Bergsten-Torralba LR, Magalhães DP, Giese EC, Nascimento CRS, Pinho JVA, Buss DF. Toxicity of three rare earth elements, and their combinations to algae, microcrustaceans, and fungi. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 201:110795. [PMID: 32544742 DOI: 10.1016/j.ecoenv.2020.110795] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 06/11/2023]
Abstract
Rare earth elements (REEs) are naturally distributed in the environment, and are increasingly being used in agriculture and high technology materials worldwide, thereby increasing anthropogenic contamination and environmental risks. There exists scarce and contradictory toxicity information about REEs; hence, more studies are required, especially on their mixtures. Thus, this study aimed to assess the toxicities of La3+, Nd3+, Sm3+, and the combinations of these elements (binary 1:1 and ternary 1:1:1), to organisms from different trophic levels: producers (the microalgae Chlorella vulgaris and Raphidocelis subcapitata), primary consumers (the microcrustaceans Daphnia similis and Artemia salina), and decomposers (the fungi Penicillium simplicissimum and Aspergillus japonicus). Ecotoxicological bioassays were performed, and toxic concentrations were determined. Thereafter, toxicities of single and mixture REEs were classified as slightly to highly toxic according to their toxic units. Finally, a concentration addition (CA) model was used to estimate how REEs interact upon combining. Nd3+ was the most toxic element for all organisms, especially D. similis (48 h LC50 9.41 mg.L-1), and was therefore classified as highly toxic. Sm3+ promoted cell agglomeration in Chlorella vulgaris and was the most toxic of the tested elements for this organism (72 h IC50 25.78 mg.L-1). The CA model revealed synergistic responses for most of the combinations, principally Nd3+ + Sm3+, which was the most toxic combination for the tested organisms. Both fungi were the most resistant organisms, and A. japonicus produced exudate and sclerotia, which help in the detoxification of chemicals. Owing not only to the fact that fungi displayed a higher resistance to REEs, but also due to the absence of regulations for REEs released from the agricultural or industrial sector, and the lack of methods to treat effluents or to dispose of technological items containing REEs, these organisms should be considered as a model for the biosorption or bioremediation of REEs. Finally, the toxic effects of REEs, particularly Nd3+, on the biota and human health should be the focus of future studies due to their increased use in technology.
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Affiliation(s)
- L R Bergsten-Torralba
- Oswaldo Cruz Institute - IOC, Program in Biodiversity and Health, Fiocruz, Rio de Janeiro - Brazil; Oswaldo Cruz Institute - IOC, Laboratory of Evaluation and Promotion of Environmental Health (LAPSA), Fiocruz, Rio de Janeiro, Brazil.
| | - D P Magalhães
- Center for Mineral Technology - CETEM, Rio de Janeiro, Brazil
| | - E C Giese
- Center for Mineral Technology - CETEM, Rio de Janeiro, Brazil
| | - C R S Nascimento
- National Institute for Quality Control in Health - INCQS, Fiocruz, Rio de Janeiro, Brazil
| | - J V A Pinho
- National School of Public Health Sergio Arouca - ENSP, Program of Public Health and Environment, Fiocruz, Rio de Janeiro, Brazil
| | - D F Buss
- Pan American Health Organization: PAHO, Washington, D.C., USA
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14
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Gilchrist CLM, Lacey HJ, Vuong D, Pitt JI, Lange L, Lacey E, Pilgaard B, Chooi YH, Piggott AM. Comprehensive chemotaxonomic and genomic profiling of a biosynthetically talented Australian fungus, Aspergillus burnettii sp. nov. Fungal Genet Biol 2020; 143:103435. [PMID: 32702474 DOI: 10.1016/j.fgb.2020.103435] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 01/09/2023]
Abstract
Aspergillus burnettii is a new species belonging to the A. alliaceus clade in Aspergillus subgenus Circumdati section Flavi isolated from peanut-growing properties in southern Queensland, Australia. A. burnettii is a fast-growing, floccose fungus with distinctive brown conidia and is a talented producer of biomass-degrading enzymes and secondary metabolites. Chemical profiling of A. burnettii revealed the metabolites ochratoxin A, kotanins, isokotanins, asperlicin E, anominine and paspalinine, which are common to subgenus Circumdati, together with burnettiene A, burnettramic acids, burnettides, and high levels of 14α-hydroxypaspalinine and hirsutide. The genome of A. burnettii was sequenced and an annotated draft genome is presented. A. burnettii is rich in secondary metabolite biosynthetic gene clusters, containing 51 polyketide synthases, 28 non-ribosomal peptide synthetases and 19 genes related to terpene biosynthesis. Functional annotation of digestive enzymes of A. burnettii and A. alliaceus revealed overlapping carbon utilisation profiles, consistent with a close phylogenetic relationship.
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Affiliation(s)
- Cameron L M Gilchrist
- School of Molecular Sciences, University of Western Australia, Crawley, WA 6009, Australia
| | - Heather J Lacey
- Microbial Screening Technologies, Smithfield, NSW 2164, Australia
| | - Daniel Vuong
- Microbial Screening Technologies, Smithfield, NSW 2164, Australia
| | - John I Pitt
- Microbial Screening Technologies, Smithfield, NSW 2164, Australia
| | - Lene Lange
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark; BioEconomy, Research & Advisory, Karensgade 5, 2500 Valby, Copenhagen, Denmark
| | - Ernest Lacey
- Microbial Screening Technologies, Smithfield, NSW 2164, Australia; Department of Molecular Sciences, Macquarie University, NSW 2109, Australia
| | - Bo Pilgaard
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Yit-Heng Chooi
- School of Molecular Sciences, University of Western Australia, Crawley, WA 6009, Australia.
| | - Andrew M Piggott
- Department of Molecular Sciences, Macquarie University, NSW 2109, Australia.
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15
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Jørgensen TR, Burggraaf AM, Arentshorst M, Schutze T, Lamers G, Niu J, Kwon MJ, Park J, Frisvad JC, Nielsen KF, Meyer V, van den Hondel CA, Dyer PS, Ram AF. Identification of SclB, a Zn(II)2Cys6 transcription factor involved in sclerotium formation in Aspergillus niger. Fungal Genet Biol 2020; 139:103377. [DOI: 10.1016/j.fgb.2020.103377] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 02/07/2020] [Accepted: 02/14/2020] [Indexed: 10/24/2022]
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16
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Ayeni KI, Sulyok M, Krska R, Ezekiel CN. Fungal and plant metabolites in industrially-processed fruit juices in Nigeria. FOOD ADDITIVES & CONTAMINANTS PART B-SURVEILLANCE 2020; 13:155-161. [PMID: 32207373 DOI: 10.1080/19393210.2020.1741691] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
There is scarce data on the mycotoxin profile in retailed fruit juices in Nigeria. Thirty-five industrially-processed fruit juice samples randomly purchased from retailers in Ogun state, Nigeria, were analysed for the presence of > 650 toxic fungal and plant metabolites using a liquid chromatography tandem mass spectrometric method. Only 18 metabolites, including 3-nitropropionic acid, alternariol methylether and emodin, but excluding citrinin, fumonisin B2, ochratoxin A and patulin, were detected in trace levels in at least one juice sample. Amygdalin, a plant cyanogen, was quantified (2.05-359 µg/L) in 40% of the samples. Although the levels of mycotoxins and toxic plant metabolites found in the juice may be relatively low, daily consumption of juices containing such low levels may contribute to dietary exposures to these natural chemical contaminants in consumers. Fruit juice processors should be encouraged to adhere strictly to good manufacturing practices in order to keep mycotoxins away from the final products.
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Affiliation(s)
- Kolawole I Ayeni
- Department of Microbiology, Babcock University , Ilishan Remo, Nigeria
| | - Michael Sulyok
- Institute for Bioanalytics and Agro-Metabolomics, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences Vienna (BOKU) , Tulln, Austria
| | - Rudolf Krska
- Institute for Bioanalytics and Agro-Metabolomics, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences Vienna (BOKU) , Tulln, Austria.,Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast , Belfast, Northern Ireland
| | - Chibundu N Ezekiel
- Department of Microbiology, Babcock University , Ilishan Remo, Nigeria.,Institute for Bioanalytics and Agro-Metabolomics, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences Vienna (BOKU) , Tulln, Austria
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17
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Chang PK, Cary JW, Lebar MD. Biosynthesis of conidial and sclerotial pigments in Aspergillus species. Appl Microbiol Biotechnol 2020; 104:2277-2286. [PMID: 31974722 DOI: 10.1007/s00253-020-10347-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/19/2019] [Accepted: 01/03/2020] [Indexed: 11/27/2022]
Abstract
Fungal pigments, which are classified as secondary metabolites, are polymerized products derived mostly from phenolic precursors with remarkable structural diversity. Pigments of conidia and sclerotia serve myriad functions. They provide tolerance against various environmental stresses such as ultraviolet light, oxidizing agents, and ionizing radiation. Some pigments even play a role in fungal pathogenesis. This review gathers available research and discusses current knowledge on the formation of conidial and sclerotial pigments in aspergilli. It examines organization of genes involved in pigment production, biosynthetic pathways, and biological functions and reevaluates some of the current dogma, especially with respect to the DHN-melanin pathway, on the production of these enigmatic polymers. A better understanding of the structure and biosynthesis of melanins and other pigments could facilitate strategies to mitigate fungal pathogenesis.
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Affiliation(s)
- Perng-Kuang Chang
- Agricultural Research Service, U. S. Department of Agriculture, Southern Regional Research Center, 1100 Robert E. Lee Boulevard, New Orleans, LA, 70124, USA.
| | - Jeffrey W Cary
- Agricultural Research Service, U. S. Department of Agriculture, Southern Regional Research Center, 1100 Robert E. Lee Boulevard, New Orleans, LA, 70124, USA.
| | - Matthew D Lebar
- Agricultural Research Service, U. S. Department of Agriculture, Southern Regional Research Center, 1100 Robert E. Lee Boulevard, New Orleans, LA, 70124, USA
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18
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Singh D, Lee S, Lee CH. Fathoming Aspergillus oryzae metabolomes in formulated growth matrices. Crit Rev Biotechnol 2019; 39:35-49. [PMID: 30037282 DOI: 10.1080/07388551.2018.1490246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 05/17/2018] [Accepted: 05/27/2018] [Indexed: 01/11/2023]
Abstract
The stochasticity of Aspergillus oryzae (Trivially: the koji mold) pan-metabolomes commensurate with its ubiquitously distributed landscapes, i.e. growth matrices have been seemed uncharted since its food fermentative systems are mostly being investigated. In this review, we explicitly have discussed the likely tendencies of A. oryzae metabolomes pertaining to its growth milieu formulated with substrate matrices of varying nature, composition, texture, and associated physicochemical parameters. We envisaged typical food matrices, namely, meju, koji, and moromi as the semi-natural cultivation models toward delineating the metabolomic patterns of the koji mold, which synergistically influences the organoleptic and functional properties of the end products. Further, we highlighted how tailored conditions in sub-natural growth matrices, i.e. synthetic cultivation media blends, inducers, and growth surfaces, may influence A. oryzae metabolomes and targeted phenotypes. In general, the sequential or synchronous growth of A. oryzae on formulated matrices results in a number of metabolic tradeoffs with its immediate microenvironment influencing its adaptive and regulatory metabolomes. In broader context, evaluating the metabolic plasticity of A. oryzae relative to the tractable variables in formulated growth matrices might help approximate its growth and metabolism in the more complex natural matrices and environs. These approaches may considerably help in the design and manipulation of hybrid cultivation systems towards the efficient harnessing of commercial molds.
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Affiliation(s)
- Digar Singh
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Korea
| | - Sunmin Lee
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Korea
| | - Choong Hwan Lee
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Korea
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19
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Fung SY, Cheong PCH, Tan NH, Ng ST, Tan CS. Nutritional evaluation on Lignosus cameronensis C. S. Tan, a medicinal Polyporaceae. IUBMB Life 2019; 71:821-826. [PMID: 30629799 DOI: 10.1002/iub.2006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 12/03/2018] [Accepted: 12/17/2018] [Indexed: 12/21/2022]
Abstract
Sclerotial powder of a cultivated species of the Tiger Milk Mushroom, Lignosus cameronensis was analysed for its nutritional components and compared against species of the same genus, Lignosus rhinocerus and Lignosus tigris. All three species have been used by indigenous tribes in Peninsular Malaysia as medicinal mushrooms. Content of carbohydrate, fibre, mineral, amino acid, palatable index, fat, ash and moisture were determined. L. cameronensis sclerotial material consists of carbohydrate (79.7%), protein (12.4%) and dietary fibre (5.4%) with low fat (1.7%) and no free sugar. It has the highest content of total carbohydrate (791 g kg-1 ), energy value (3,700 kcal kg-1 ) and calcium (0.85 g kg-1 ). The crude protein content (123 g kg-1 ) is comparable to that of L. rhinocerus with its main amino acids consisting of glutamic acid, aspartic acid and leucine. The umami index is determined to be 0.27. The total essential amino acid (45 g kg-1 ) is comparable to that of L. tigris. The main mineral is potassium (1.51 g kg-1 ) and the Na/K ratio was <0.6. Heavy metals such as mercury, cadmium, lead and arsenic were absent. L. cameronensis has the highest amount of food energy, total carbohydrate and calcium compared to those of both L. rhinocerus and L. tigris. The essential amino acids comprised almost 40% of the total amino acid content, slightly more than that reported from sclerotial powder of the L. tigris. © 2019 IUBMB Life, 9999(9999):1-6, 2019.
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Affiliation(s)
- Shin Yee Fung
- Medicinal Mushroom Research Group, Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Peter Chiew Hing Cheong
- Medicinal Mushroom Research Group, Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Nget Hong Tan
- Medicinal Mushroom Research Group, Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Szu Ting Ng
- Ligno Biotech Sdn. Bhd., Seri Kembangan, Selangor, Malaysia
| | - Chon Seng Tan
- Ligno Biotech Sdn. Bhd., Seri Kembangan, Selangor, Malaysia
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20
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Zhang J, Chen H, Sumarah MW, Gao Q, Wang D, Zhang Y. veA Gene Acts as a Positive Regulator of Conidia Production, Ochratoxin A Biosynthesis, and Oxidative Stress Tolerance in Aspergillus niger. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:13199-13208. [PMID: 30456955 DOI: 10.1021/acs.jafc.8b04523] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The veA gene is a key regulator governing morphogenetic development and secondary metabolism in many fungi. Here, we characterized and disrupted a veA orthologue in an ochratoxigenic Aspergillus niger strain. Morphological development, ochratoxin A (OTA) biosynthesis, and oxidative stress tolerance in the wild-type and veA disruption strains were further analyzed. Accordingly, the link between the veA gene and development of specific gene brlA, OTA biosynthesis key gene pks, and oxidative-stress-tolerance-related gene cat was explored. Results demonstrated that the veA gene acts as a positive regulator of conidia production, OTA biosynthesis, and oxidative stress tolerance in A. niger, regardless of light conditions. Darkness promoted conidial production and OTA biosynthesis in the A. niger wild-type strain. Our results contribute to a better understanding of the veA regulatory mechanism and suggest the veA gene as a potential target for developing control strategies for A. niger infection and OTA biosynthesis.
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Affiliation(s)
| | | | - Mark W Sumarah
- London Research and Development Centre , Agriculture and Agri-Food Canada , 1391 Sandford Street , London , Ontario N5V 4T3 , Canada
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21
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Frisvad JC, Møller LLH, Larsen TO, Kumar R, Arnau J. Safety of the fungal workhorses of industrial biotechnology: update on the mycotoxin and secondary metabolite potential of Aspergillus niger, Aspergillus oryzae, and Trichoderma reesei. Appl Microbiol Biotechnol 2018; 102:9481-9515. [PMID: 30293194 PMCID: PMC6208954 DOI: 10.1007/s00253-018-9354-1] [Citation(s) in RCA: 183] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 08/28/2018] [Accepted: 08/29/2018] [Indexed: 12/11/2022]
Abstract
This review presents an update on the current knowledge of the secondary metabolite potential of the major fungal species used in industrial biotechnology, i.e., Aspergillus niger, Aspergillus oryzae, and Trichoderma reesei. These species have a long history of safe use for enzyme production. Like most microorganisms that exist in a challenging environment in nature, these fungi can produce a large variety and number of secondary metabolites. Many of these compounds present several properties that make them attractive for different industrial and medical applications. A description of all known secondary metabolites produced by these species is presented here. Mycotoxins are a very limited group of secondary metabolites that can be produced by fungi and that pose health hazards in humans and other vertebrates when ingested in small amounts. Some mycotoxins are species-specific. Here, we present scientific basis for (1) the definition of mycotoxins including an update on their toxicity and (2) the clarity on misclassification of species and their mycotoxin potential reported in literature, e.g., A. oryzae has been wrongly reported as an aflatoxin producer, due to misclassification of Aspergillus flavus strains. It is therefore of paramount importance to accurately describe the mycotoxins that can potentially be produced by a fungal species that is to be used as a production organism and to ensure that production strains are not capable of producing mycotoxins during enzyme production. This review is intended as a reference paper for authorities, companies, and researchers dealing with secondary metabolite assessment, risk evaluation for food or feed enzyme production, or considerations on the use of these species as production hosts.
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Affiliation(s)
- Jens C Frisvad
- Department of Biotechnology and Biomedicine (DTU Bioengineering), Technical University of Denmark, Søltofts Plads, B. 221, 2800, Kongens Lyngby, Denmark.
| | - Lars L H Møller
- Department of Product Safety, Novozymes A/S, Krogshoejvej 36, 2880, Bagsvaerd, Denmark
| | - Thomas O Larsen
- Department of Biotechnology and Biomedicine (DTU Bioengineering), Technical University of Denmark, Søltofts Plads, B. 221, 2800, Kongens Lyngby, Denmark
| | - Ravi Kumar
- Department of Genomics and Bioinformatics, Novozymes Inc., 1445 Drew Ave., Davis, CA, 95618, USA
| | - José Arnau
- Department of Fungal Strain Technology and Strain Approval Support, Novozymes A/S, Krogshoejvej 36, 2880, Bagsvaerd, Denmark
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22
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Vesth TC, Nybo JL, Theobald S, Frisvad JC, Larsen TO, Nielsen KF, Hoof JB, Brandl J, Salamov A, Riley R, Gladden JM, Phatale P, Nielsen MT, Lyhne EK, Kogle ME, Strasser K, McDonnell E, Barry K, Clum A, Chen C, LaButti K, Haridas S, Nolan M, Sandor L, Kuo A, Lipzen A, Hainaut M, Drula E, Tsang A, Magnuson JK, Henrissat B, Wiebenga A, Simmons BA, Mäkelä MR, de Vries RP, Grigoriev IV, Mortensen UH, Baker SE, Andersen MR. Investigation of inter- and intraspecies variation through genome sequencing of Aspergillus section Nigri. Nat Genet 2018; 50:1688-1695. [PMID: 30349117 DOI: 10.1038/s41588-018-0246-1] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 08/23/2018] [Indexed: 01/27/2023]
Abstract
Aspergillus section Nigri comprises filamentous fungi relevant to biomedicine, bioenergy, health, and biotechnology. To learn more about what genetically sets these species apart, as well as about potential applications in biotechnology and biomedicine, we sequenced 23 genomes de novo, forming a full genome compendium for the section (26 species), as well as 6 Aspergillus niger isolates. This allowed us to quantify both inter- and intraspecies genomic variation. We further predicted 17,903 carbohydrate-active enzymes and 2,717 secondary metabolite gene clusters, which we condensed into 455 distinct families corresponding to compound classes, 49% of which are only found in single species. We performed metabolomics and genetic engineering to correlate genotypes to phenotypes, as demonstrated for the metabolite aurasperone, and by heterologous transfer of citrate production to Aspergillus nidulans. Experimental and computational analyses showed that both secondary metabolism and regulation are key factors that are significant in the delineation of Aspergillus species.
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Affiliation(s)
- Tammi C Vesth
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Jane L Nybo
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Sebastian Theobald
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Jens C Frisvad
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Thomas O Larsen
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Kristian F Nielsen
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Jakob B Hoof
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Julian Brandl
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Asaf Salamov
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Robert Riley
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA.,Amyris, Inc., Emeryville, CA, USA
| | - John M Gladden
- US Department of Energy Joint BioEnergy Institute, Emeryville, CA, USA.,Sandia National Laboratory, Livermore, CA, USA
| | - Pallavi Phatale
- US Department of Energy Joint BioEnergy Institute, Emeryville, CA, USA.,Chemical and Biological Process Development Group, Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Morten T Nielsen
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Ellen K Lyhne
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Martin E Kogle
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Kimchi Strasser
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
| | - Erin McDonnell
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
| | - Kerrie Barry
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Alicia Clum
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Cindy Chen
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Kurt LaButti
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Sajeet Haridas
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Matt Nolan
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Laura Sandor
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Alan Kuo
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Anna Lipzen
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Matthieu Hainaut
- Architecture et Fonction des Macromolécules Biologiques, CNRS UMR 7257, Aix-Marseille University, Marseille, France.,Institut National de la Recherche Agronomique, USC 1408 Architecture et Fonction des Macromolécules Biologiques, Marseille, France
| | - Elodie Drula
- Architecture et Fonction des Macromolécules Biologiques, CNRS UMR 7257, Aix-Marseille University, Marseille, France.,Institut National de la Recherche Agronomique, USC 1408 Architecture et Fonction des Macromolécules Biologiques, Marseille, France
| | - Adrian Tsang
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
| | - Jon K Magnuson
- US Department of Energy Joint BioEnergy Institute, Emeryville, CA, USA.,Chemical and Biological Process Development Group, Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques, CNRS UMR 7257, Aix-Marseille University, Marseille, France.,Institut National de la Recherche Agronomique, USC 1408 Architecture et Fonction des Macromolécules Biologiques, Marseille, France.,Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ad Wiebenga
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute and Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Blake A Simmons
- US Department of Energy Joint BioEnergy Institute, Emeryville, CA, USA.,Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Miia R Mäkelä
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute and Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands.,Department of Microbiology, University of Helsinki, Helsinki, Finland
| | - Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute and Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - 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
| | - Uffe H Mortensen
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Scott E Baker
- US Department of Energy Joint BioEnergy Institute, Emeryville, CA, USA. .,Environmental Molecular Sciences Division, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA.
| | - Mikael R Andersen
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark.
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Ejmal MA, Holland DJ, MacDiarmid RM, Pearson MN. The Effect of Aspergillus Thermomutatus Chrysovirus 1 on the Biology of Three Aspergillus Species. Viruses 2018; 10:E539. [PMID: 30279352 PMCID: PMC6213286 DOI: 10.3390/v10100539] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 09/25/2018] [Accepted: 09/29/2018] [Indexed: 12/16/2022] Open
Abstract
This study determined the effects of Aspergillus thermomutatus chrysovirus 1 (AthCV1), isolated from Aspergillus thermomutatus, on A. fumigatus, A. nidulans and A. niger. Protoplasts of virus-free isolates of A. fumigatus, A. nidulans and A. niger were transfected with purified AthCV1 particles and the phenotype, growth and sporulation of the isogenic AthCV1-free and AthCV1-infected lines assessed at 20 °C and 37 °C and gene expression data collected at 37 °C. AthCV1-free and AthCV1-infected A. fumigatus produced only conidia at both temperatures but more than ten-fold reduced compared to the AthCV1-infected line. Conidiation was also significantly reduced in infected lines of A. nidulans and A. niger at 37 °C. AthCV1-infected lines of A. thermomutatus and A. nidulans produced large numbers of ascospores at both temperatures, whereas the AthCV1-free line of the former did not produce ascospores. AthCV1-infected lines of all species developed sectoring phenotypes with sclerotia produced in aconidial sectors of A. niger at 37 °C. AthCV1 was detected in 18% of sclerotia produced by AthCV1-infected A. niger and 31% of ascospores from AthCV1-infected A. nidulans. Transcriptome analysis of the naturally AthCV1-infected A. thermomutatus and the three AthCV1-transfected Aspergillus species showed altered gene expression as a result of AthCV1-infection. The results demonstrate that AthCV1 can infect a range of Aspergillus species resulting in reduced sporulation, a potentially useful attribute for a biological control agent.
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Affiliation(s)
- Mahjoub A Ejmal
- School of Biological Sciences, the University of Auckland, Auckland 1142 New Zealand.
| | - David J Holland
- Infectious Diseases Unit, Division of Medicine, Middlemore Hospital, Auckland 1640, New Zealand.
| | - Robin M MacDiarmid
- School of Biological Sciences, the University of Auckland, Auckland 1142 New Zealand.
- Plant and Food Research, Auckland 1142, New Zealand.
| | - Michael N Pearson
- School of Biological Sciences, the University of Auckland, Auckland 1142 New Zealand.
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Velvet domain protein VosA represses the zinc cluster transcription factor SclB regulatory network for Aspergillus nidulans asexual development, oxidative stress response and secondary metabolism. PLoS Genet 2018; 14:e1007511. [PMID: 30044771 PMCID: PMC6078315 DOI: 10.1371/journal.pgen.1007511] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 08/06/2018] [Accepted: 06/22/2018] [Indexed: 12/30/2022] Open
Abstract
The NF-κB-like velvet domain protein VosA (viability of spores) binds to more than 1,500 promoter sequences in the filamentous fungus Aspergillus nidulans. VosA inhibits premature induction of the developmental activator gene brlA, which promotes asexual spore formation in response to environmental cues as light. VosA represses a novel genetic network controlled by the sclB gene. SclB function is antagonistic to VosA, because it induces the expression of early activator genes of asexual differentiation as flbC and flbD as well as brlA. The SclB controlled network promotes asexual development and spore viability, but is independent of the fungal light control. SclB interactions with the RcoA transcriptional repressor subunit suggest additional inhibitory functions on transcription. SclB links asexual spore formation to the synthesis of secondary metabolites including emericellamides, austinol as well as dehydroaustinol and activates the oxidative stress response of the fungus. The fungal VosA-SclB regulatory system of transcription includes a VosA control of the sclB promoter, common and opposite VosA and SclB control functions of fungal development and several additional regulatory genes. The relationship between VosA and SclB illustrates the presence of a convoluted surveillance apparatus of transcriptional control, which is required for accurate fungal development and the linkage to the appropriate secondary metabolism. Velvet domain proteins of filamentous fungi are structurally similar to Rel-homology domains of mammalian NF-κB proteins. Velvet and NF-κB proteins control regulatory circuits of downstream transcriptional networks for cellular differentiation, survival and stress responses. Velvet proteins interconnect developmental programs with secondary metabolism in fungi. The velvet protein VosA binds to more than ten percent of the Aspergillus nidulans promoters and is important for the spatial and temporal control of asexual spore formation from conidiophores. A novel VosA-dependent genetic network has been identified and is controlled by the zinc cluster protein SclB. Although zinc cluster proteins constitute one of the most abundant classes of transcription factors in fungi, only a small amount is characterized. SclB is a repression target of VosA and both transcription factors are part of a mutual control in the timely adjusted choreography of asexual sporulation in A. nidulans. SclB acts at the interphase of asexual development and secondary metabolism and interconnects both programs with an adequate oxidative stress response. This study underlines the complexity of different hierarchical levels of the fungal velvet protein transcriptional network for developmental programs and interconnected secondary metabolism.
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25
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ROS and trehalose regulate sclerotial development in Rhizoctonia solani AG-1 IA. Fungal Biol 2018; 122:322-332. [DOI: 10.1016/j.funbio.2018.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 02/06/2018] [Accepted: 02/13/2018] [Indexed: 01/06/2023]
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26
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Singh D, Lee CH. Volatiles Mediated Interactions Between Aspergillus oryzae Strains Modulate Morphological Transition and Exometabolomes. Front Microbiol 2018; 9:628. [PMID: 29670599 PMCID: PMC5893800 DOI: 10.3389/fmicb.2018.00628] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 03/19/2018] [Indexed: 11/13/2022] Open
Abstract
Notwithstanding its mitosporic nature, an improbable morpho-transformation state i. e., sclerotial development (SD), is vaguely known in Aspergillus oryzae. Nevertheless an intriguing phenomenon governing mold's development and stress response, the effects of exogenous factors engendering SD, especially the volatile organic compounds (VOCs) mediated interactions (VMI) pervasive in microbial niches have largely remained unexplored. Herein, we examined the effects of intra-species VMI on SD in A. oryzae RIB 40, followed by comprehensive analyses of associated growth rates, pH alterations, biochemical phenotypes, and exometabolomes. We cultivated A. oryzae RIB 40 (S1VMI: KACC 44967) opposite a non-SD partner strain, A. oryzae (S2: KCCM 60345), conditioning VMI in a specially designed “twin plate assembly.” Notably, SD in S1VMI was delayed relative to its non-conditioned control (S1) cultivated without partner strain (S2) in twin plate. Selectively evaluating A. oryzae RIB 40 (S1VMI vs. S1) for altered phenotypes concomitant to SD, we observed a marked disparity for corresponding growth rates (S1VMI < S1)7days, media pH (S1VMI > S1)7days, and biochemical characteristics viz., protease (S1VMI > S1)7days, amylase (S1VMI > nS1)3–7days, and antioxidants (S1VMI > S1)7days levels. The partial least squares—discriminant analysis (PLS-DA) of gas chromatography—time of flight—mass spectrometry (GC-TOF-MS) datasets for primary metabolites exhibited a clustered pattern (PLS1, 22.04%; PLS2, 11.36%), with 7 days incubated S1VMI extracts showed higher abundance of amino acids, sugars, and sugar alcohols with lower organic acids and fatty acids levels, relative to S1. Intriguingly, the higher amino acid and sugar alcohol levels were positively correlated with antioxidant activity, likely impeding SD in S1VMI. Further, the PLS-DA (PLS1, 18.11%; PLS2, 15.02%) based on liquid chromatography—mass spectrometry (LC-MS) datasets exhibited a notable disparity for post-SD (9–11 days) sample extracts with higher oxylipins and 13-desoxypaxilline levels in S1VMI relative to S1, intertwining Aspergillus morphogenesis and secondary metabolism. The analysis of VOCs for the 7 days incubated samples displayed considerably higher accumulation of C-8 compounds in the headspace of twin-plate experimental sets (S1VMI:S2) compared to those in non-conditioned controls (S1 and S2—without respective partner strains), potentially triggering altered morpho-transformation and concurring biochemical as well as metabolic states in molds.
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Affiliation(s)
- Digar Singh
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, South Korea
| | - Choong H Lee
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, South Korea
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27
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Gerin D, González-Candelas L, Ballester AR, Pollastro S, De Miccolis Angelini RM, Faretra F. Functional Characterization of the alb1 Orthologue Gene in the Ochratoxigenic Fungus Aspergillus carbonarius (AC49 strain). Toxins (Basel) 2018. [PMID: 29534508 PMCID: PMC5869408 DOI: 10.3390/toxins10030120] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Aspergillus carbonarius, belonging to the group Nigri, is the main species responsible for contamination by ochratoxin A (OTA) in grapes and derivative products. OTA can accumulate in the mycelium and in black conidia of the fungus and released into the matrix. Here, we have deleted in A. carbonarius the alb1 orthologue gene of A. fumigatus, involved in melanin biosynthesis. Three A. carbonarius Δalb1 mutants were characterized for morphologic traits and OTA production on different media and temperatures. Δalb1 mutants showed a fawn color of conidia associated with a significant reduction of the conidiogenesis and a statistically significant increase (p ≤ 0.01) of total OTA production as compared to the wild type (WT) strain. The alb1 gene somehow affected OTA partitioning since in Δalb1 mutants OTA amount was lower in conidia and was more abundantly secreted into the medium as compared to the WT. On grape berries the Δalb1 mutants and the WT caused lesions with similar sizes but OTA amount in berry tissues was higher for the mutants. These results demonstrate that A. carbonarius conidia pigmentation is largely dependent on polyketide biosynthesis. The gene is not directly involved in virulence and its deletion affects morphological features and OTA production in the fungus.
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Affiliation(s)
- Donato Gerin
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, via Amendola 165/A, 70126 Bari, Italy.
| | - Luis González-Candelas
- Instituto de Agroquímica y Tecnología de Alimentos, IATA-CSIC, Calle Agustín Escardino 7, Paterna, 46980 Valencia, Spain.
| | - Ana-Rosa Ballester
- Instituto de Agroquímica y Tecnología de Alimentos, IATA-CSIC, Calle Agustín Escardino 7, Paterna, 46980 Valencia, Spain.
| | - Stefania Pollastro
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, via Amendola 165/A, 70126 Bari, Italy.
- SELGE Network of Public Research Laboratories, via Amendola 165/A, 70126 Bari, Italy.
| | - Rita Milvia De Miccolis Angelini
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, via Amendola 165/A, 70126 Bari, Italy.
- SELGE Network of Public Research Laboratories, via Amendola 165/A, 70126 Bari, Italy.
| | - Francesco Faretra
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, via Amendola 165/A, 70126 Bari, Italy.
- SELGE Network of Public Research Laboratories, via Amendola 165/A, 70126 Bari, Italy.
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28
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Abstract
Approximately 20% of species in the fungal kingdom are only known to reproduce by asexual means despite the many supposed advantages of sexual reproduction. However, in recent years, sexual cycles have been induced in a series of emblematic "asexual" species. We describe how these discoveries were made, building on observations of evidence for sexual potential or "cryptic sexuality" from population genetic analyses; the presence, distribution, and functionality of mating-type genes; genome analyses revealing the presence of genes linked to sexuality; the functionality of sex-related genes; and formation of sex-related developmental structures. We then describe specific studies that led to the discovery of mating and sex in certain Candida, Aspergillus, Penicillium, and Trichoderma species and discuss the implications of sex including the beneficial exploitation of the sexual cycle. We next consider whether there might be any truly asexual fungal species. We suggest that, although rare, imperfect fungi may genuinely be present in nature and that certain human activities, combined with the genetic flexibility that is a hallmark of the fungal kingdom, might favor the evolution of asexuality under certain conditions. Finally, we argue that fungal species should not be thought of as simply asexual or sexual, but rather as being composed of isolates on a continuum of sexual fertility.
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30
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Tang MC, Lin HC, Li D, Zou Y, Li J, Xu W, Cacho RA, Hillenmeyer ME, Garg NK, Tang Y. Discovery of Unclustered Fungal Indole Diterpene Biosynthetic Pathways through Combinatorial Pathway Reassembly in Engineered Yeast. J Am Chem Soc 2015; 137:13724-7. [PMID: 26469304 DOI: 10.1021/jacs.5b06108] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The structural diversity and biological activities of fungal indole diterpenes (IDTs) are generated in large part by the IDT cyclases (IDTCs). Identifying different IDTCs from IDT biosynthetic pathways is therefore important toward understanding how these enzymes introduce chemical diversity from a common linear precursor. However, IDTCs involved in the cyclization of the well-known aflavinine subgroup of IDTs have not been discovered. Here, using Saccharomyces cerevisiae as a heterologous host and a phylogenetically guided enzyme mining approach, we combinatorially assembled IDT biosynthetic pathways using IDTCs homologues identified from different fungal hosts. We identified the genetically standalone IDTCs involved in the cyclization of aflavinine and anominine and produced new IDTs not previously isolated. The cyclization mechanisms of the new IDTCs were proposed based on the yeast reconstitution results. Our studies demonstrate heterologous pathway assembly is a useful tool in the reconstitution of unclustered biosynthetic pathways.
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Affiliation(s)
| | | | - Dehai Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China , Qingdao, Shandong 266003, P. R. China
| | | | - Jian Li
- Stanford Genome Technology Center, Stanford University , Palo Alto, California 94304, United States
| | | | | | - Maureen E Hillenmeyer
- Stanford Genome Technology Center, Stanford University , Palo Alto, California 94304, United States
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31
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Garmendia G, Vero S. Occurrence and biodiversity of Aspergillus section Nigri on 'Tannat' grapes in Uruguay. Int J Food Microbiol 2015; 216:31-9. [PMID: 26398282 DOI: 10.1016/j.ijfoodmicro.2015.08.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 08/10/2015] [Accepted: 08/26/2015] [Indexed: 10/23/2022]
Abstract
Ochratoxin A (OTA) is a nephrotoxic mycotoxin which has been found worldwide as a contaminant in wines. It is produced on grapes mainly by molds from Aspergillus section Nigri. This study has demonstrated for the first time the occurrence of black aspergilli on Tannat grapes from Uruguay, in a two year survey. Aspergillus uvarum (uniseriate) and Aspergillus welwitschiae (from Aspergillusniger aggregate) were the prevalent species whereas Aspergillus carbonarius which is considered the main OTA producing species was not detected. OTA production in culture medium was evaluated for native isolates from A. niger aggregate and compared to levels produced by a type strain of A. carbonarius. This work also includes the development of quick and easy molecular methods to identify black aspergilli to species level, avoiding sequencing.
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Affiliation(s)
- Gabriela Garmendia
- Cátedra de Microbiología, Departamento de Biociencias, Facultad de Química, UDELAR. 11800, Montevideo, Uruguay.
| | - Silvana Vero
- Cátedra de Microbiología, Departamento de Biociencias, Facultad de Química, UDELAR. 11800, Montevideo, Uruguay
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32
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Frisvad JC, Larsen TO. Chemodiversity in the genus Aspergillus. Appl Microbiol Biotechnol 2015; 99:7859-77. [DOI: 10.1007/s00253-015-6839-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 07/08/2015] [Accepted: 07/11/2015] [Indexed: 10/23/2022]
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33
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Pisani C, Nguyen TT, Gubler WD. A novel fungal fruiting structure formed by Aspergillus niger and Aspergillus carbonarius in grape berries. Fungal Biol 2015; 119:784-90. [PMID: 26321727 DOI: 10.1016/j.funbio.2015.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 04/29/2015] [Accepted: 05/06/2015] [Indexed: 01/04/2023]
Abstract
Sour rot, is a pre-harvest disease that affects many grape varieties. Sour rot symptoms include initial berry cracking and breakdown of berry tissue. This is a disease complex with many filamentous fungi and bacteria involved, but is usually initiated by Aspergillus niger or Aspergillus carbonarius. Usually, by the time one sees the rot there are many other organisms involved and it is difficult to attribute the disease to one species. In this study two species of Aspergillus were shown to produce a previously unknown fruiting structure in infected berries. The nodulous morphology, bearing conidia, suggests them to be an 'everted polymorphic stroma'. This structure forms freely inside the berry pulp and assumes multiple shapes and sizes, sometimes sclerotium-like in form. It is composed of a mass of vegetative hyphae with or without tissue of the host containing spores or fruiting bodies bearing spores. Artificially inoculated berries placed in soil in winter showed the possible overwintering function of the fruiting body. Inoculated berry clusters on standing vines produced fruiting structures within 21 d post inoculation when wounds were made at veraison or after (July-September). Histological studies confirmed that the fruiting structure was indeed fungal tissue.
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Affiliation(s)
- Cristina Pisani
- Department of Plant Pathology, University of California Davis, Davis 95616, USA
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34
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Induced sclerotium formation exposes new bioactive metabolites from Aspergillus sclerotiicarbonarius. J Antibiot (Tokyo) 2015; 68:603-8. [DOI: 10.1038/ja.2015.40] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 03/09/2015] [Accepted: 03/16/2015] [Indexed: 01/06/2023]
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35
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Calvo AM, Cary JW. Association of fungal secondary metabolism and sclerotial biology. Front Microbiol 2015; 6:62. [PMID: 25762985 PMCID: PMC4329819 DOI: 10.3389/fmicb.2015.00062] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/18/2015] [Indexed: 11/13/2022] Open
Abstract
Fungal secondary metabolism and morphological development have been shown to be intimately associated at the genetic level. Much of the literature has focused on the co-regulation of secondary metabolite production (e.g., sterigmatocystin and aflatoxin in Aspergillus nidulans and Aspergillus flavus, respectively) with conidiation or formation of sexual fruiting bodies. However, many of these genetic links also control sclerotial production. Sclerotia are resistant structures produced by a number of fungal genera. They also represent the principal source of primary inoculum for some phytopathogenic fungi. In nature, higher plants often concentrate secondary metabolites in reproductive structures as a means of defense against herbivores and insects. By analogy, fungi also sequester a number of secondary metabolites in sclerotia that act as a chemical defense system against fungivorous predators. These include antiinsectant compounds such as tetramic acids, indole diterpenoids, pyridones, and diketopiperazines. This chapter will focus on the molecular mechanisms governing production of secondary metabolites and the role they play in sclerotial development and fungal ecology, with particular emphasis on Aspergillus species. The global regulatory proteins VeA and LaeA, components of the velvet nuclear protein complex, serve as virulence factors and control both development and secondary metabolite production in many Aspergillus species. We will discuss a number of VeA- and LaeA-regulated secondary metabolic gene clusters in A. flavus that are postulated to be involved in sclerotial morphogenesis and chemical defense. The presence of multiple regulatory factors that control secondary metabolism and sclerotial formation suggests that fungi have evolved these complex regulatory mechanisms as a means to rapidly adapt chemical responses to protect sclerotia from predators, competitors and other environmental stressors.
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Affiliation(s)
- Ana M Calvo
- Department of Biological Sciences, Northern Illinois University DeKalb, IL, USA
| | - Jeffrey W Cary
- Southern Regional Research Center, United States Department of Agriculture - Agricultural Research Service New Orleans, LA, USA
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36
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37
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Olarte RA, Horn BW, Singh R, Carbone I. Sexual recombination in Aspergillus tubingensis. Mycologia 2015; 107:307-12. [PMID: 25572097 DOI: 10.3852/14-233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Aspergillus tubingensis from section Nigri (black Aspergilli) is closely related to A. niger and is used extensively in the industrial production of enzymes and organic acids. We recently discovered sexual reproduction in A. tubingensis, and in this study we demonstrate that the progeny are products of meiosis. Progeny were obtained from six crosses involving five MAT1-1 strains and two MAT1-2 strains. We examined three loci, including mating type (MAT), RNA polymerase II (RPB2) and β-tubulin (BT2), and found that 84% (58/69) of progeny were recombinants. Recombination associated with sexual reproduction in A. tubingensis provides a new option for the genetic improvement of industrial strains for enzyme and organic acid production.
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Affiliation(s)
- Rodrigo A Olarte
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695
| | - Bruce W Horn
- National Peanut Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Dawson, Georgia 39842
| | - Rakhi Singh
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695
| | - Ignazio Carbone
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695
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38
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Frisvad JC. Taxonomy, chemodiversity, and chemoconsistency of Aspergillus, Penicillium, and Talaromyces species. Front Microbiol 2015; 5:773. [PMID: 25628613 PMCID: PMC4290622 DOI: 10.3389/fmicb.2014.00773] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 12/17/2014] [Indexed: 11/17/2022] Open
Abstract
Aspergillus, Penicillium, and Talaromyces are among the most chemically inventive of all fungi, producing a wide array of secondary metabolites (exometabolites). The three genera are holophyletic in a cladistic sense and polythetic classes in an anagenetic or functional sense, and contain 344, 354, and 88 species, respectively. New developments in classification, cladification, and nomenclature have meant that the species, series, and sections suggested are natural groups that share many extrolites, including exometabolites, exoproteins, exocarbohydrates, and exolipids in addition to morphological features. The number of exometabolites reported from these species is very large, and genome sequencing projects have shown that a large number of additional exometabolites may be expressed, given the right conditions (“cryptic” gene clusters for exometabolites). The exometabolites are biosynthesized via shikimic acid, tricarboxylic acid cycle members, nucleotides, carbohydrates or as polyketides, non-ribosomal peptides, terpenes, or mixtures of those. The gene clusters coding for these compounds contain genes for the biosynthetic building blocks, the linking of these building blocks, tailoring enzymes, resistance for own products, and exporters. Species within a series or section in Aspergillus, Penicillium, and Talaromyces have many exometabolites in common, seemingly acquired by cladogenesis, but some the gene clusters for autapomorphic exometabolites may have been acquired by horizontal gene transfer. Despite genome sequencing efforts, and the many breakthroughs these will give, it is obvious that epigenetic factors play a large role in evolution and function of chemodiversity, and better methods for characterizing the epigenome are needed. Most of the individual species of the three genera produce a consistent and characteristic profile of exometabolites, but growth medium variations, stimulation by exometabolites from other species, and variations in abiotic intrinsic and extrinsic environmental factors such as pH, temperature, redox potential, and water activity will add significantly to the number of biosynthetic families expressed in anyone species. An example of the shared exometabolites in a natural group such as Aspergillus section Circumdati series Circumdati is that most, but not all species produce penicillic acids, aspyrones, neoaspergillic acids, xanthomegnins, melleins, aspergamides, circumdatins, and ochratoxins, in different combinations.
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Affiliation(s)
- Jens C Frisvad
- Section of Eukaryotic Biotechnology, Department of Systems Biology, Technical University of Denmark Kongens Lyngby, Denmark
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Susca A, Proctor RH, Butchko RA, Haidukowski M, Stea G, Logrieco A, Moretti A. Variation in the fumonisin biosynthetic gene cluster in fumonisin-producing and nonproducing black aspergilli. Fungal Genet Biol 2014; 73:39-52. [DOI: 10.1016/j.fgb.2014.09.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 09/04/2014] [Accepted: 09/24/2014] [Indexed: 01/13/2023]
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Obase K, Douhan GW, Matsuda Y, Smith ME. Culturable fungal assemblages growing within Cenococcum sclerotia in forest soils. FEMS Microbiol Ecol 2014; 90:708-17. [PMID: 25229424 DOI: 10.1111/1574-6941.12428] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 09/11/2014] [Accepted: 09/12/2014] [Indexed: 11/27/2022] Open
Abstract
The ectomycorrhizal fungus Cenococcum geophilum (Ascomycota, Dothideomycetes) forms black, round to irregular sclerotia in forest soils. Fungi that colonize the sclerotia appear to affect sclerotia viability and may play an important role in the life history of Cenococcum. Some of the fungi could also affect nutrient cycling by decomposing Cenococcum sclerotia, which are melanized and recalcitrant to decay. We used a culture-based method to document the fungal communities growing inside surface-sterilized sclerotia that were collected from forest soils. Cenococcum was successfully isolated from 297 of 971 sclerotia whereas 427 sclerotia hosted fungi other than Cenococcum. DNA barcoding of the internal transcribed spacer rDNA followed by grouping at 97% sequence similarity yielded 85 operational taxonomic units (OTUs) that consisted primarily of Ascomycota (e.g. Chaetothyriales, Eurotiales, Helotiales, Pleosporales) and a few Basidiomycota and Mucoromycotina. Although most fungal OTUs were infrequently cultured, several OTUs such as members of Asterostroma, Cladophialophora, Oidiodendron, and Pleosporales were common and found across many sites. Our results suggest that Cenococcum sclerotia act as a substrate for diverse fungi. The occurrence of several OTUs in sclerotia across many sites suggests that these fungi may be active parasites of Cenococcum sclerotia or may preferentially use sclerotia as a nutrient source.
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Affiliation(s)
- Keisuke Obase
- Department of Plant Pathology, University of Florida, Gainesville, FL, USA
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Petersen LM, Hoeck C, Frisvad JC, Gotfredsen CH, Larsen TO. Dereplication guided discovery of secondary metabolites of mixed biosynthetic origin from Aspergillus aculeatus. Molecules 2014; 19:10898-921. [PMID: 25068785 PMCID: PMC6271215 DOI: 10.3390/molecules190810898] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 07/15/2014] [Accepted: 07/16/2014] [Indexed: 11/16/2022] Open
Abstract
Investigation of the chemical profile of the industrially important black filamentous fungus Aspergillus aculeatus by UHPLC-DAD-HRMS and subsequent dereplication has led to the discovery of several novel compounds. Isolation and extensive 1D and 2D NMR spectroscopic analyses allowed for structural elucidation of a dioxomorpholine, a unique okaramine, an aflavinine and three novel structures of mixed biosynthetic origin, which we have named aculenes A-C. Moreover, known analogues of calbistrins, okaramines and secalonic acids were detected. All novel compounds were tested for antifungal activity against Candida albicans, however all showed only weak or no activity. Aspergillus aculeatus IBT 21030 was additionally shown to be capable of producing sclerotia. Examination of the sclerotia revealed a highly regulated production of metabolites in these morphological structures.
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Affiliation(s)
- Lene M Petersen
- Chemodiversity Group, Department of Systems Biology, Søltofts Plads B221, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark.
| | - Casper Hoeck
- Department of Chemistry, Kemitorvet B201, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark.
| | - Jens C Frisvad
- Chemodiversity Group, Department of Systems Biology, Søltofts Plads B221, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark.
| | - Charlotte H Gotfredsen
- Department of Chemistry, Kemitorvet B201, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark.
| | - Thomas O Larsen
- Chemodiversity Group, Department of Systems Biology, Søltofts Plads B221, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark.
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