1
|
Guo A, Zhang Y, Ji Y, Chen X, Zhang W, Liu X, Yan D, Fang W, Li Y, Cao A, Wang Q. The potential for reducing aflatoxin B1 contamination of stored peanuts by soil disinfection. JOURNAL OF HAZARDOUS MATERIALS 2024; 469:133916. [PMID: 38479137 DOI: 10.1016/j.jhazmat.2024.133916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/06/2024] [Accepted: 02/27/2024] [Indexed: 04/07/2024]
Abstract
Aflatoxins from the fungus Aspergillus flavus (A. flavus) that contaminate stored peanuts is a major hazard to human health worldwide. Reducing A. flavus in soil can decrease the risk of aflatoxins in stored peanuts. In this experiment, we determined whether peanuts grown on soil fumigated with dazomet (DZ), metham sodium (MS), allyl isothiocyanate (AITC), chloropicrin (PIC) or dimethyl disulfide (DMDS) would reduce of the quantity of A. flavus and its toxin's presence. The results of bioassays and field tests showed that PIC was the most effective fumigant for preventing and controlling A. flavus, followed by MS. PIC and MS applied to the soil for 14 d resulted in LD50 values against A. flavus of 3.558 and 4.893 mg kg-1, respectively, leading to almost 100% and 98.82% effectiveness of A. flavus, respectively. Peanuts harvested from fumigated soil and then stored for 60 d resulted in undetectable levels of aflatoxin B1 (AFB1) compared to unfumigated soil that contained 0.64 ug kg-1 of AFB1, which suggested that soil fumigation can reduce the probability of aflatoxin contamination during peanut storage and showed the potential to increase the safety of peanuts consumed by humans. Further research is planned to determine the practical value of our research in commercial practice.
Collapse
Affiliation(s)
- Anmin Guo
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yi Zhang
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yutong Ji
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xinhua Chen
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Wei Zhang
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xuemei Liu
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Dongdong Yan
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Wensheng Fang
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yuan Li
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Aocheng Cao
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Qiuxia Wang
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| |
Collapse
|
2
|
Smaoui S, D’Amore T, Tarapoulouzi M, Agriopoulou S, Varzakas T. Aflatoxins Contamination in Feed Commodities: From Occurrence and Toxicity to Recent Advances in Analytical Methods and Detoxification. Microorganisms 2023; 11:2614. [PMID: 37894272 PMCID: PMC10609407 DOI: 10.3390/microorganisms11102614] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 10/18/2023] [Accepted: 10/21/2023] [Indexed: 10/29/2023] Open
Abstract
Synthesized by the secondary metabolic pathway in Aspergilli, aflatoxins (AFs) cause economic and health issues and are culpable for serious harmful health and economic matters affecting consumers and global farmers. Consequently, the detection and quantification of AFs in foods/feeds are paramount from food safety and security angles. Nowadays, incessant attempts to develop sensitive and rapid approaches for AFs identification and quantification have been investigated, worldwide regulations have been established, and the safety of degrading enzymes and reaction products formed in the AF degradation process has been explored. Here, occurrences in feed commodities, innovative methods advanced for AFs detection, regulations, preventive strategies, biological detoxification, removal, and degradation methods were deeply reviewed and presented. This paper showed a state-of-the-art and comprehensive review of the recent progress on AF contamination in feed matrices with the intention of inspiring interests in both academia and industry.
Collapse
Affiliation(s)
- Slim Smaoui
- Laboratory of Microbial, Enzymatic Biotechnology and Biomolecules (LBMEB), Center of Biotechnology of Sfax, University of Sfax-Tunisia, Sfax 3029, Tunisia
| | - Teresa D’Amore
- IRCCS CROB, Centro di Riferimento Oncologico della Basilicata, 85028 Rionero in Vulture, Italy;
| | - Maria Tarapoulouzi
- Department of Chemistry, Faculty of Pure and Applied Science, University of Cyprus, P.O. Box 20537, Nicosia CY-1678, Cyprus;
| | - Sofia Agriopoulou
- Department of Food Science and Technology, University of the Peloponnese, Antikalamos, 24100 Kalamata, Greece;
| | - Theodoros Varzakas
- Department of Food Science and Technology, University of the Peloponnese, Antikalamos, 24100 Kalamata, Greece;
| |
Collapse
|
3
|
Xiao S, Wu Y, Gao S, Zhou M, Liu Z, Xiong Q, Jiang L, Yuan G, Li L, Yang L. Deciphering the Hazardous Effects of AFB1 and T-2 Toxins: Unveiling Toxicity and Oxidative Stress Mechanisms in PK15 Cells and Mouse Kidneys. Toxins (Basel) 2023; 15:503. [PMID: 37624260 PMCID: PMC10467080 DOI: 10.3390/toxins15080503] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/04/2023] [Accepted: 08/10/2023] [Indexed: 08/26/2023] Open
Abstract
In China, animal feeds are frequently contaminated with a range of mycotoxins, with Aflatoxin B1 (AFB1) and T-2 toxin (T-2) being two highly toxic mycotoxins. This study investigates the combined nephrotoxicity of AFB1 and T-2 on PK15 cells and murine renal tissues and their related oxidative stress mechanisms. PK15 cells were treated with the respective toxin concentrations for 24 h, and oxidative stress-related indicators were assessed. The results showed that the combination of AFB1 and T-2 led to more severe cellular damage and oxidative stress compared to exposure to the individual toxins (p < 0.05). In the in vivo study, pathological examination revealed that the kidney tissue of mice exposed to the combined toxins showed signs of glomerular atrophy. The contents of oxidative stress-related indicators were significantly increased in the kidney tissue (p < 0.05). These findings suggest that the combined toxins cause significant oxidative damage to mouse kidneys. The study highlights the importance of considering the combined effects of mycotoxins in animal feed, particularly AFB1 and T-2, which can lead to severe nephrotoxicity and oxidative stress in PK15 cells and mouse kidneys. The findings have important implications for animal feed safety and regulatory policy.
Collapse
Affiliation(s)
- Shuai Xiao
- College of Veterinary Medicine, Hunan Agricultural University, No. 1 Nongda Road, Furong District, Changsha 410128, China; (S.X.); (Y.W.); (S.G.); (M.Z.); (Q.X.); (L.J.); (G.Y.); (L.L.)
| | - Yingxin Wu
- College of Veterinary Medicine, Hunan Agricultural University, No. 1 Nongda Road, Furong District, Changsha 410128, China; (S.X.); (Y.W.); (S.G.); (M.Z.); (Q.X.); (L.J.); (G.Y.); (L.L.)
| | - Suisui Gao
- College of Veterinary Medicine, Hunan Agricultural University, No. 1 Nongda Road, Furong District, Changsha 410128, China; (S.X.); (Y.W.); (S.G.); (M.Z.); (Q.X.); (L.J.); (G.Y.); (L.L.)
| | - Mingxia Zhou
- College of Veterinary Medicine, Hunan Agricultural University, No. 1 Nongda Road, Furong District, Changsha 410128, China; (S.X.); (Y.W.); (S.G.); (M.Z.); (Q.X.); (L.J.); (G.Y.); (L.L.)
| | - Zhiwei Liu
- Wuhan Animal Disease Control Center, No. 170, Erqi Road, Jiang’an District, Wuhan 430014, China;
| | - Qianbo Xiong
- College of Veterinary Medicine, Hunan Agricultural University, No. 1 Nongda Road, Furong District, Changsha 410128, China; (S.X.); (Y.W.); (S.G.); (M.Z.); (Q.X.); (L.J.); (G.Y.); (L.L.)
| | - Lihuang Jiang
- College of Veterinary Medicine, Hunan Agricultural University, No. 1 Nongda Road, Furong District, Changsha 410128, China; (S.X.); (Y.W.); (S.G.); (M.Z.); (Q.X.); (L.J.); (G.Y.); (L.L.)
| | - Guoxiang Yuan
- College of Veterinary Medicine, Hunan Agricultural University, No. 1 Nongda Road, Furong District, Changsha 410128, China; (S.X.); (Y.W.); (S.G.); (M.Z.); (Q.X.); (L.J.); (G.Y.); (L.L.)
| | - Linfeng Li
- College of Veterinary Medicine, Hunan Agricultural University, No. 1 Nongda Road, Furong District, Changsha 410128, China; (S.X.); (Y.W.); (S.G.); (M.Z.); (Q.X.); (L.J.); (G.Y.); (L.L.)
| | - Lingchen Yang
- College of Veterinary Medicine, Hunan Agricultural University, No. 1 Nongda Road, Furong District, Changsha 410128, China; (S.X.); (Y.W.); (S.G.); (M.Z.); (Q.X.); (L.J.); (G.Y.); (L.L.)
| |
Collapse
|
4
|
Nji QN, Babalola OO, Mwanza M. Soil Aspergillus Species, Pathogenicity and Control Perspectives. J Fungi (Basel) 2023; 9:766. [PMID: 37504754 PMCID: PMC10381279 DOI: 10.3390/jof9070766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/05/2023] [Accepted: 07/18/2023] [Indexed: 07/29/2023] Open
Abstract
Five Aspergillus sections have members that are established agricultural pests and producers of different metabolites, threatening global food safety. Most of these pathogenic Aspergillus species have been isolated from almost all major biomes. The soil remains the primary habitat for most of these cryptic fungi. This review explored some of the ecological attributes that have contributed immensely to the success of the pathogenicity of some members of the genus Aspergillus over time. Hence, the virulence factors of the genus Aspergillus, their ecology and others were reviewed. Furthermore, some biological control techniques were recommended. Pathogenic effects of Aspergillus species are entirely accidental; therefore, the virulence evolution prediction model in such species becomes a challenge, unlike their obligate parasite counterparts. In all, differences in virulence among organisms involved both conserved and species-specific genetic factors. If the impacts of climate change continue, new cryptic Aspergillus species will emerge and mycotoxin contamination risks will increase in all ecosystems, as these species can metabolically adjust to nutritional and biophysical challenges. As most of their gene clusters are silent, fungi continue to be a source of underexplored bioactive compounds. The World Soil Charter recognizes the relevance of soil biodiversity in supporting healthy soil functions. The question of how a balance may be struck between supporting healthy soil biodiversity and the control of toxic fungi species in the field to ensure food security is therefore pertinent. Numerous advanced strategies and biocontrol methods so far remain the most environmentally sustainable solution to the control of toxigenic fungi in the field.
Collapse
Affiliation(s)
- Queenta Ngum Nji
- Food Security and Safety Focus Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa
| | - Olubukola Oluranti Babalola
- Food Security and Safety Focus Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa
| | - Mulunda Mwanza
- Food Security and Safety Focus Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa
- Department of Animal Health, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Ren X, Branà MT, Haidukowski M, Gallo A, Zhang Q, Logrieco AF, Li P, Zhao S, Altomare C. Potential of Trichoderma spp. for Biocontrol of Aflatoxin-Producing Aspergillus flavus. Toxins (Basel) 2022; 14:toxins14020086. [PMID: 35202114 PMCID: PMC8875375 DOI: 10.3390/toxins14020086] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 12/16/2022] Open
Abstract
The inhibitory action of 20 antagonistic Trichoderma isolates against the aflatoxigenic isolate A. flavus ITEM 9 (Af-9) and their efficacy in reducing aflatoxin formation in vitro were examined. Production of metabolites with inhibitory effect by the Trichoderma isolates was also investigated. Antagonistic effect against Af-9 was assessed by inhibition of radial growth of the colonies and by fungal interactions in dual confrontation tests. A total of 8 out of 20 isolates resulted in a significant growth inhibition of 3-day-old cultures of Af-9, ranging from 13% to 65%. A total of 14 isolates reduced significantly the aflatoxin B1 (AfB1) content of 15-day-old Af-9 cultures; 4 were ineffective, and 2 increased AfB1. Reduction of AfB1 content was up to 84.9% and 71.1% in 7- and 15-day-old cultures, respectively. Since the inhibition of Af-9 growth by metabolites of Trichoderma was not necessarily associated with inhibition of AfB1 production and vice versa, we investigated the mechanism of reduction of AfB1 content at the molecular level by examining two strains: one (T60) that reduced both growth and mycotoxin content; and the other (T44) that reduced mycotoxin content but not Af-9 growth. The expression analyses for the two regulatory genes aflR and aflS, and the structural genes aflA, aflD, aflO and aflQ of the aflatoxin biosynthesis cluster indicated that neither strain was able to downregulate the aflatoxin synthesis, leading to the conclusion that the AfB1 content reduction by these Trichoderma strains was based on other mechanisms, such as enzyme degradation or complexation. Although further studies are envisaged to identify the metabolites involved in the biocontrol of A. flavus and prevention of aflatoxin accumulation, as well as for assessment of the efficacy under controlled and field conditions, Trichoderma spp. qualify as promising agents and possible alternative options to other biocontrol agents already in use.
Collapse
Affiliation(s)
- Xianfeng Ren
- Institute of Agricultural Quality Standards and Testing Technology, Shandong Academy of Agricultural Sciences, Jinan 250100, China;
- Shandong Provincial Key Laboratory of Test Technology on Food Quality and Safety, Jinan 250100, China
| | - Maria Teresa Branà
- Institute of Sciences of Food Production, National Research Council, 70126 Bari, Italy; (M.T.B.); (M.H.)
| | - Miriam Haidukowski
- Institute of Sciences of Food Production, National Research Council, 70126 Bari, Italy; (M.T.B.); (M.H.)
| | - Antonia Gallo
- Institute of Sciences of Food Production, National Research Council, 73100 Lecce, Italy; (A.G.); (A.F.L.)
| | - Qi Zhang
- Oil Crops Research Institute, The Chinese Academy of Agricultural Sciences, Wuhan 430062, China; (Q.Z.); (P.L.)
| | - Antonio F. Logrieco
- Institute of Sciences of Food Production, National Research Council, 73100 Lecce, Italy; (A.G.); (A.F.L.)
| | - Peiwu Li
- Oil Crops Research Institute, The Chinese Academy of Agricultural Sciences, Wuhan 430062, China; (Q.Z.); (P.L.)
| | - Shancang Zhao
- Institute of Agricultural Quality Standards and Testing Technology, Shandong Academy of Agricultural Sciences, Jinan 250100, China;
- Shandong Provincial Key Laboratory of Test Technology on Food Quality and Safety, Jinan 250100, China
- Correspondence: (S.Z.); (C.A.); Tel.: +86-27-868-12943 (S.Z.); +39-80-592-9318 (C.A.)
| | - Claudio Altomare
- Institute of Sciences of Food Production, National Research Council, 70126 Bari, Italy; (M.T.B.); (M.H.)
- Correspondence: (S.Z.); (C.A.); Tel.: +86-27-868-12943 (S.Z.); +39-80-592-9318 (C.A.)
| |
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Luis JM, Carbone I, Payne GA, Bhatnagar D, Cary JW, Moore GG, Lebar MD, Wei Q, Mack B, Ojiambo PS. Characterization of morphological changes within stromata during sexual reproduction in Aspergillus flavus. Mycologia 2020; 112:908-920. [PMID: 32821029 DOI: 10.1080/00275514.2020.1800361] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Aspergillus flavus contaminates agricultural products worldwide with carcinogenic aflatoxins that pose a serious health risk to humans and animals. The fungus survives adverse environmental conditions through production of sclerotia. When fertilized by a compatible conidium of an opposite mating type, a sclerotium transforms into a stroma within which ascocarps, asci, and ascospores are formed. However, the transition from a sclerotium to a stroma during sexual reproduction in A. flavus is not well understood. Early events during the interaction between sexually compatible strains of A. flavus were visualized using conidia of a green fluorescent protein (GFP)-labeled MAT1-1 strain and sclerotia of an mCherry-labeled MAT1-2 strain. Both conidia and sclerotia of transformed strains germinated to produce hyphae within 24 h of incubation. Hyphal growth of these two strains produced what appeared to be a network of interlocking hyphal strands that were observed at the base of the mCherry-labeled sclerotia (i.e., region in contact with agar surface) after 72 h of incubation. At 5 wk following incubation, intracellular green-fluorescent hyphal strands were observed within the stromatal matrix of the mCherry-labeled strain. Scanning electron microscopy of stromata from a high- and low-fertility cross and unmated sclerotia was used to visualize the formation and development of sexual structures within the stromatal and sclerotial matrices, starting at the time of crossing and thereafter every 2 wk until 8 wk of incubation. Morphological differences between sclerotia and stromata became apparent at 4 wk of incubation. Internal hyphae and croziers were detected inside multiple ascocarps that developed within the stromatal matrix of the high-fertility cross but were not detected in the matrix of the low-fertility cross or the unmated sclerotia. At 6 to 8 wk of incubation, hyphal tips produced numerous asci, each containing one to eight ascospores that emerged out of an ascus following the breakdown of the ascus wall. These observations broaden our knowledge of early events during sexual reproduction and suggest that hyphae from the conidium-producing strain may be involved in the early stages of sexual reproduction in A. flavus. When combined with omics data, these findings could be useful in further exploration of the molecular and biochemical mechanisms underlying sexual reproduction in A. flavus.
Collapse
Affiliation(s)
- Jane Marian Luis
- Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University , Raleigh, NC 27695
| | - Ignazio Carbone
- Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University , Raleigh, NC 27695
| | - Gary A Payne
- Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University , Raleigh, NC 27695
| | - Deepak Bhatnagar
- Southern Regional Research Center, Agricultural Research Service , United States Department of Agriculture, New Orleans, Louisiana 70124
| | - Jeffrey W Cary
- Southern Regional Research Center, Agricultural Research Service , United States Department of Agriculture, New Orleans, Louisiana 70124
| | - Geromy G Moore
- Southern Regional Research Center, Agricultural Research Service , United States Department of Agriculture, New Orleans, Louisiana 70124
| | - Matthew D Lebar
- Southern Regional Research Center, Agricultural Research Service , United States Department of Agriculture, New Orleans, Louisiana 70124
| | - Qijian Wei
- Southern Regional Research Center, Agricultural Research Service , United States Department of Agriculture, New Orleans, Louisiana 70124
| | - Brian Mack
- Southern Regional Research Center, Agricultural Research Service , United States Department of Agriculture, New Orleans, Louisiana 70124
| | - Peter S Ojiambo
- Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University , Raleigh, NC 27695
| |
Collapse
|
10
|
Houbraken J, Kocsubé S, Visagie C, Yilmaz N, Wang XC, Meijer M, Kraak B, Hubka V, Bensch K, Samson R, Frisvad J. Classification of Aspergillus, Penicillium, Talaromyces and related genera ( Eurotiales): An overview of families, genera, subgenera, sections, series and species. Stud Mycol 2020; 95:5-169. [PMID: 32855739 PMCID: PMC7426331 DOI: 10.1016/j.simyco.2020.05.002] [Citation(s) in RCA: 264] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The Eurotiales is a relatively large order of Ascomycetes with members frequently having positive and negative impact on human activities. Species within this order gain attention from various research fields such as food, indoor and medical mycology and biotechnology. In this article we give an overview of families and genera present in the Eurotiales and introduce an updated subgeneric, sectional and series classification for Aspergillus and Penicillium. Finally, a comprehensive list of accepted species in the Eurotiales is given. The classification of the Eurotiales at family and genus level is traditionally based on phenotypic characters, and this classification has since been challenged using sequence-based approaches. Here, we re-evaluated the relationships between families and genera of the Eurotiales using a nine-gene sequence dataset. Based on this analysis, the new family Penicillaginaceae is introduced and four known families are accepted: Aspergillaceae, Elaphomycetaceae, Thermoascaceae and Trichocomaceae. The Eurotiales includes 28 genera: 15 genera are accommodated in the Aspergillaceae (Aspergillago, Aspergillus, Evansstolkia, Hamigera, Leiothecium, Monascus, Penicilliopsis, Penicillium, Phialomyces, Pseudohamigera, Pseudopenicillium, Sclerocleista, Warcupiella, Xerochrysium and Xeromyces), eight in the Trichocomaceae (Acidotalaromyces, Ascospirella, Dendrosphaera, Rasamsonia, Sagenomella, Talaromyces, Thermomyces, Trichocoma), two in the Thermoascaceae (Paecilomyces, Thermoascus) and one in the Penicillaginaceae (Penicillago). The classification of the Elaphomycetaceae was not part of this study, but according to literature two genera are present in this family (Elaphomyces and Pseudotulostoma). The use of an infrageneric classification system has a long tradition in Aspergillus and Penicillium. Most recent taxonomic studies focused on the sectional level, resulting in a well-established sectional classification in these genera. In contrast, a series classification in Aspergillus and Penicillium is often outdated or lacking, but is still relevant, e.g., the allocation of a species to a series can be highly predictive in what functional characters the species might have and might be useful when using a phenotype-based identification. The majority of the series in Aspergillus and Penicillium are invalidly described and here we introduce a new series classification. Using a phylogenetic approach, often supported by phenotypic, physiologic and/or extrolite data, Aspergillus is subdivided in six subgenera, 27 sections (five new) and 75 series (73 new, one new combination), and Penicillium in two subgenera, 32 sections (seven new) and 89 series (57 new, six new combinations). Correct identification of species belonging to the Eurotiales is difficult, but crucial, as the species name is the linking pin to information. Lists of accepted species are a helpful aid for researchers to obtain a correct identification using the current taxonomic schemes. In the most recent list from 2014, 339 Aspergillus, 354 Penicillium and 88 Talaromyces species were accepted. These numbers increased significantly, and the current list includes 446 Aspergillus (32 % increase), 483 Penicillium (36 % increase) and 171 Talaromyces (94 % increase) species, showing the large diversity and high interest in these genera. We expanded this list with all genera and species belonging to the Eurotiales (except those belonging to Elaphomycetaceae). The list includes 1 187 species, distributed over 27 genera, and contains MycoBank numbers, collection numbers of type and ex-type cultures, subgenus, section and series classification data, information on the mode of reproduction, and GenBank accession numbers of ITS, beta-tubulin (BenA), calmodulin (CaM) and RNA polymerase II second largest subunit (RPB2) gene sequences.
Collapse
Key Words
- Acidotalaromyces Houbraken, Frisvad & Samson
- Acidotalaromyces lignorum (Stolk) Houbraken, Frisvad & Samson
- Ascospirella Houbraken, Frisvad & Samson
- Ascospirella lutea (Zukal) Houbraken, Frisvad & Samson
- Aspergillus chaetosartoryae Hubka, Kocsubé & Houbraken
- Classification
- Evansstolkia Houbraken, Frisvad & Samson
- Evansstolkia leycettana (H.C. Evans & Stolk) Houbraken, Frisvad & Samson
- Hamigera brevicompacta (H.Z. Kong) Houbraken, Frisvad & Samson
- Infrageneric classification
- New combinations, series
- New combinations, species
- New genera
- New names
- New sections
- New series
- New taxa
- Nomenclature
- Paecilomyces lagunculariae (C. Ram) Houbraken, Frisvad & Samson
- Penicillaginaceae Houbraken, Frisvad & Samson
- Penicillago kabunica (Baghd.) Houbraken, Frisvad & Samson
- Penicillago mirabilis (Beliakova & Milko) Houbraken, Frisvad & Samson
- Penicillago moldavica (Milko & Beliakova) Houbraken, Frisvad & Samson
- Phialomyces arenicola (Chalab.) Houbraken, Frisvad & Samson
- Phialomyces humicoloides (Bills & Heredia) Houbraken, Frisvad & Samson
- Phylogeny
- Polythetic classes
- Pseudohamigera Houbraken, Frisvad & Samson
- Pseudohamigera striata (Raper & Fennell) Houbraken, Frisvad & Samson
- Talaromyces resinae (Z.T. Qi & H.Z. Kong) Houbraken & X.C. Wang
- Talaromyces striatoconidius Houbraken, Frisvad & Samson
- Taxonomic novelties: New family
- Thermoascus verrucosus (Samson & Tansey) Houbraken, Frisvad & Samson
- Thermoascus yaguchii Houbraken, Frisvad & Samson
- in Aspergillus: sect. Bispori S.W. Peterson, Varga, Frisvad, Samson ex Houbraken
- in Aspergillus: ser. Acidohumorum Houbraken & Frisvad
- in Aspergillus: ser. Inflati (Stolk & Samson) Houbraken & Frisvad
- in Penicillium: sect. Alfrediorum Houbraken & Frisvad
- in Penicillium: ser. Adametziorum Houbraken & Frisvad
- in Penicillium: ser. Alutacea (Pitt) Houbraken & Frisvad
- sect. Crypta Houbraken & Frisvad
- sect. Eremophila Houbraken & Frisvad
- sect. Formosana Houbraken & Frisvad
- sect. Griseola Houbraken & Frisvad
- sect. Inusitata Houbraken & Frisvad
- sect. Lasseniorum Houbraken & Frisvad
- sect. Polypaecilum Houbraken & Frisvad
- sect. Raperorum S.W. Peterson, Varga, Frisvad, Samson ex Houbraken
- sect. Silvatici S.W. Peterson, Varga, Frisvad, Samson ex Houbraken
- sect. Vargarum Houbraken & Frisvad
- ser. Alliacei Houbraken & Frisvad
- ser. Ambigui Houbraken & Frisvad
- ser. Angustiporcata Houbraken & Frisvad
- ser. Arxiorum Houbraken & Frisvad
- ser. Atramentosa Houbraken & Frisvad
- ser. Aurantiobrunnei Houbraken & Frisvad
- ser. Avenacei Houbraken & Frisvad
- ser. Bertholletiarum Houbraken & Frisvad
- ser. Biplani Houbraken & Frisvad
- ser. Brevicompacta Houbraken & Frisvad
- ser. Brevipedes Houbraken & Frisvad
- ser. Brunneouniseriati Houbraken & Frisvad
- ser. Buchwaldiorum Houbraken & Frisvad
- ser. Calidousti Houbraken & Frisvad
- ser. Canini Houbraken & Frisvad
- ser. Carbonarii Houbraken & Frisvad
- ser. Cavernicolarum Houbraken & Frisvad
- ser. Cervini Houbraken & Frisvad
- ser. Chevalierorum Houbraken & Frisvad
- ser. Cinnamopurpurea Houbraken & Frisvad
- ser. Circumdati Houbraken & Frisvad
- ser. Clavigera Houbraken & Frisvad
- ser. Conjuncti Houbraken & Frisvad
- ser. Copticolarum Houbraken & Frisvad
- ser. Coremiiformes Houbraken & Frisvad
- ser. Corylophila Houbraken & Frisvad
- ser. Costaricensia Houbraken & Frisvad
- ser. Cremei Houbraken & Frisvad
- ser. Crustacea (Pitt) Houbraken & Frisvad
- ser. Dalearum Houbraken & Frisvad
- ser. Deflecti Houbraken & Frisvad
- ser. Egyptiaci Houbraken & Frisvad
- ser. Erubescentia (Pitt) Houbraken & Frisvad
- ser. Estinogena Houbraken & Frisvad
- ser. Euglauca Houbraken & Frisvad
- ser. Fennelliarum Houbraken & Frisvad
- ser. Flavi Houbraken & Frisvad
- ser. Flavipedes Houbraken & Frisvad
- ser. Fortuita Houbraken & Frisvad
- ser. Fumigati Houbraken & Frisvad
- ser. Funiculosi Houbraken & Frisvad
- ser. Gallaica Houbraken & Frisvad
- ser. Georgiensia Houbraken & Frisvad
- ser. Goetziorum Houbraken & Frisvad
- ser. Gracilenta Houbraken & Frisvad
- ser. Halophilici Houbraken & Frisvad
- ser. Herqueorum Houbraken & Frisvad
- ser. Heteromorphi Houbraken & Frisvad
- ser. Hoeksiorum Houbraken & Frisvad
- ser. Homomorphi Houbraken & Frisvad
- ser. Idahoensia Houbraken & Frisvad
- ser. Implicati Houbraken & Frisvad
- ser. Improvisa Houbraken & Frisvad
- ser. Indica Houbraken & Frisvad
- ser. Japonici Houbraken & Frisvad
- ser. Jiangxiensia Houbraken & Frisvad
- ser. Kalimarum Houbraken & Frisvad
- ser. Kiamaensia Houbraken & Frisvad
- ser. Kitamyces Houbraken & Frisvad
- ser. Lapidosa (Pitt) Houbraken & Frisvad
- ser. Leporum Houbraken & Frisvad
- ser. Leucocarpi Houbraken & Frisvad
- ser. Livida Houbraken & Frisvad
- ser. Longicatenata Houbraken & Frisvad
- ser. Macrosclerotiorum Houbraken & Frisvad
- ser. Monodiorum Houbraken & Frisvad
- ser. Multicolores Houbraken & Frisvad
- ser. Neoglabri Houbraken & Frisvad
- ser. Neonivei Houbraken & Frisvad
- ser. Nidulantes Houbraken & Frisvad
- ser. Nigri Houbraken & Frisvad
- ser. Nivei Houbraken & Frisvad
- ser. Nodula Houbraken & Frisvad
- ser. Nomiarum Houbraken & Frisvad
- ser. Noonimiarum Houbraken & Frisvad
- ser. Ochraceorosei Houbraken & Frisvad
- ser. Olivimuriarum Houbraken & Frisvad
- ser. Osmophila Houbraken & Frisvad
- ser. Paradoxa Houbraken & Frisvad
- ser. Paxillorum Houbraken & Frisvad
- ser. Penicillioides Houbraken & Frisvad
- ser. Phoenicea Houbraken & Frisvad
- ser. Pinetorum (Pitt) Houbraken & Frisvad
- ser. Polypaecilum Houbraken & Frisvad
- ser. Pulvini Houbraken & Frisvad
- ser. Quercetorum Houbraken & Frisvad
- ser. Raistrickiorum Houbraken & Frisvad
- ser. Ramigena Houbraken & Frisvad
- ser. Restricti Houbraken & Frisvad
- ser. Robsamsonia Houbraken & Frisvad
- ser. Rolfsiorum Houbraken & Frisvad
- ser. Roseopurpurea Houbraken & Frisvad
- ser. Rubri Houbraken & Frisvad
- ser. Salinarum Houbraken & Frisvad
- ser. Samsoniorum Houbraken & Frisvad
- ser. Saturniformia Houbraken & Frisvad
- ser. Scabrosa Houbraken & Frisvad
- ser. Sclerotigena Houbraken & Frisvad
- ser. Sclerotiorum Houbraken & Frisvad
- ser. Sheariorum Houbraken & Frisvad
- ser. Simplicissima Houbraken & Frisvad
- ser. Soppiorum Houbraken & Frisvad
- ser. Sparsi Houbraken & Frisvad
- ser. Spathulati Houbraken & Frisvad
- ser. Spelaei Houbraken & Frisvad
- ser. Speluncei Houbraken & Frisvad
- ser. Spinulosa Houbraken & Frisvad
- ser. Stellati Houbraken & Frisvad
- ser. Steyniorum Houbraken & Frisvad
- ser. Sublectatica Houbraken & Frisvad
- ser. Sumatraensia Houbraken & Frisvad
- ser. Tamarindosolorum Houbraken & Frisvad
- ser. Teporium Houbraken & Frisvad
- ser. Terrei Houbraken & Frisvad
- ser. Thermomutati Houbraken & Frisvad
- ser. Thiersiorum Houbraken & Frisvad
- ser. Thomiorum Houbraken & Frisvad
- ser. Unguium Houbraken & Frisvad
- ser. Unilaterales Houbraken & Frisvad
- ser. Usti Houbraken & Frisvad
- ser. Verhageniorum Houbraken & Frisvad
- ser. Versicolores Houbraken & Frisvad
- ser. Virgata Houbraken & Frisvad
- ser. Viridinutantes Houbraken & Frisvad
- ser. Vitricolarum Houbraken & Frisvad
- ser. Wentiorum Houbraken & Frisvad
- ser. Westlingiorum Houbraken & Frisvad
- ser. Whitfieldiorum Houbraken & Frisvad
- ser. Xerophili Houbraken & Frisvad
- series Tularensia (Pitt) Houbraken & Frisvad
Collapse
Affiliation(s)
- J. Houbraken
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - S. Kocsubé
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - C.M. Visagie
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, P. Bag X20, Hatfield, Pretoria, 0028, South Africa
| | - N. Yilmaz
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, P. Bag X20, Hatfield, Pretoria, 0028, South Africa
| | - X.-C. Wang
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, No. 3, 1st Beichen West Road, Chaoyang District, Beijing, 100101, China
| | - M. Meijer
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - B. Kraak
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - V. Hubka
- Department of Botany, Charles University in Prague, Prague, Czech Republic
| | - K. Bensch
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - R.A. Samson
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - J.C. Frisvad
- Department of Biotechnology and Biomedicine Technical University of Denmark, Søltofts Plads, B. 221, Kongens Lyngby, DK 2800, Denmark
| |
Collapse
|
11
|
Byun KH, Park SY, Lee DU, Chun HS, Ha SD. Effect of UV-C irradiation on inactivation of Aspergillus flavus and Aspergillus parasiticus and quality parameters of roasted coffee bean (Coffea arabica L.). Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2020; 37:507-518. [DOI: 10.1080/19440049.2020.1711971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Kye-Hwan Byun
- Department of Food Science and Technology, Advanced Food Safety Research Group, BrainKorea21 Plus, Chung-Ang University, Ansung, Republic of Korea
| | - Shin Young Park
- Department of Seafood and Aquaculture Science, Institute of Marine Industry, Gyeongsang National University, Tongyeong, Republic of Korea
| | - Dong Un Lee
- Department of Food Science and Technology, Chung-Ang University, Ansung, Republic of Korea
| | - Hyang Sook Chun
- Department of Food Science and Technology, Advanced Food Safety Research Group, BrainKorea21 Plus, Chung-Ang University, Ansung, Republic of Korea
| | - Sang-Do Ha
- Department of Food Science and Technology, Advanced Food Safety Research Group, BrainKorea21 Plus, Chung-Ang University, Ansung, Republic of Korea
| |
Collapse
|
12
|
Norlia M, Jinap S, Nor-Khaizura MAR, Radu S, Samsudin NIP, Azri FA. Aspergillus section Flavi and Aflatoxins: Occurrence, Detection, and Identification in Raw Peanuts and Peanut-Based Products Along the Supply Chain. Front Microbiol 2019; 10:2602. [PMID: 31824445 PMCID: PMC6886384 DOI: 10.3389/fmicb.2019.02602] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/25/2019] [Indexed: 12/19/2022] Open
Abstract
Aflatoxin contamination in foods is a global concern as they are carcinogenic, teratogenic and mutagenic compounds. The aflatoxin-producing fungi, mainly from the Aspergillus section Flavi, are ubiquitous in nature and readily contaminate various food commodities, thereby affecting human's health. The incidence of aflatoxigenic Aspergillus spp. and aflatoxins in various types of food, especially raw peanuts and peanut-based products along the supply chain has been a concern particularly in countries having tropical and sub-tropical climate, including Malaysia. These climatic conditions naturally support the growth of Aspergillus section Flavi, especially A. flavus, particularly when raw peanuts and peanut-based products are stored under inappropriate conditions. Peanut supply chain generally consists of several major stakeholders which include the producers, collectors, exporters, importers, manufacturers, retailers and finally, the consumers. A thorough examination of the processes along the supply chain reveals that Aspergillus section Flavi and aflatoxins could occur at any step along the chain, from farm to table. Thus, this review aims to give an overview on the prevalence of Aspergillus section Flavi and the occurrence of aflatoxins in raw peanuts and peanut-based products, the impact of aflatoxins on global trade, and aflatoxin management in peanuts with a special focus on peanut supply chain in Malaysia. Furthermore, aflatoxin detection and quantification methods as well as the identification of Aspergillus section Flavi are also reviewed herein. This review could help to shed light to the researchers, peanut stakeholders and consumers on the risk of aflatoxin contamination in peanuts along the supply chain.
Collapse
Affiliation(s)
- Mahror Norlia
- Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Malaysia
- School of Industrial Technology, Universiti Sains Malaysia, Penang, Malaysia
| | - Selamat Jinap
- Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Malaysia
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang, Malaysia
| | | | - Son Radu
- Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Malaysia
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang, Malaysia
| | - Nik Iskandar Putra Samsudin
- Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Malaysia
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang, Malaysia
| | - Farah Asilah Azri
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang, Malaysia
| |
Collapse
|
13
|
Lewis MH, Carbone I, Luis JM, Payne GA, Bowen KL, Hagan AK, Kemerait R, Heiniger R, Ojiambo PS. Biocontrol Strains Differentially Shift the Genetic Structure of Indigenous Soil Populations of Aspergillus flavus. Front Microbiol 2019; 10:1738. [PMID: 31417528 PMCID: PMC6685141 DOI: 10.3389/fmicb.2019.01738] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 07/15/2019] [Indexed: 01/22/2023] Open
Abstract
Biocontrol using non-aflatoxigenic strains of Aspergillus flavus has the greatest potential to mitigate aflatoxin contamination in agricultural produce. However, factors that influence the efficacy of biocontrol agents in reducing aflatoxin accumulation under field conditions are not well-understood. Shifts in the genetic structure of indigenous soil populations of A. flavus following application of biocontrol products Afla-Guard and AF36 were investigated to determine how these changes can influence the efficacy of biocontrol strains in reducing aflatoxin contamination. Soil samples were collected from maize fields in Alabama, Georgia, and North Carolina in 2012 and 2013 to determine changes in the population genetic structure of A. flavus in the soil following application of the biocontrol strains. A. flavus L was the most dominant species of Aspergillus section Flavi with a frequency ranging from 61 to 100%, followed by Aspergillus parasiticus that had a frequency of <35%. The frequency of A. flavus L increased, while that of A. parasiticus decreased after application of biocontrol strains. A total of 112 multilocus haplotypes (MLHs) were inferred from 1,282 isolates of A. flavus L using multilocus sequence typing of the trpC, mfs, and AF17 loci. A. flavus individuals belonging to the Afla-Guard MLH in the IB lineage were the most dominant before and after application of biocontrol strains, while individuals of the AF36 MLH in the IC lineage were either recovered in very low frequencies or not recovered at harvest. There were no significant (P > 0.05) differences in the frequency of individuals with MAT1-1 and MAT1-2 for clone-corrected MLH data, an indication of a recombining population resulting from sexual reproduction. Population mean mutation rates were not different across temporal and spatial scales indicating that mutation alone is not a driving force in observed multilocus sequence diversity. Clustering based on principal component analysis identified two distinct evolutionary lineages (IB and IC) across all three states. Additionally, patristic distance analysis revealed phylogenetic incongruency among single locus phylogenies which suggests ongoing genetic exchange and recombination. Levels of aflatoxin accumulation were very low except in North Carolina in 2012, where aflatoxin levels were significantly (P < 0.05) lower in grain from treated compared to untreated plots. Phylogenetic analysis showed that Afla-Guard was more effective than AF36 in shifting the indigenous soil populations of A. flavus toward the non-toxigenic or low aflatoxin producing IB lineage. These results suggest that Afla-Guard, which matches the genetic and ecological structure of indigenous soil populations of A. flavus in Alabama, Georgia, and North Carolina, is likely to be more effective in reducing aflatoxin accumulation and will also persist longer in the soil than AF36 in the southeastern United States.
Collapse
Affiliation(s)
- Mary H Lewis
- Department of Entomology and Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC, United States
| | - Ignazio Carbone
- Department of Entomology and Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC, United States
| | - Jane M Luis
- Department of Entomology and Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC, United States
| | - Gary A Payne
- Department of Entomology and Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC, United States
| | - Kira L Bowen
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | - Austin K Hagan
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | - Robert Kemerait
- Department of Plant Pathology, University of Georgia, Coastal Plain Experiment Station, Tifton, GA, United States
| | - Ron Heiniger
- Department of Crop Science, North Carolina State University, Raleigh, NC, United States
| | - Peter S Ojiambo
- Department of Entomology and Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC, United States
| |
Collapse
|
14
|
Frisvad J, Hubka V, Ezekiel C, Hong SB, Nováková A, Chen A, Arzanlou M, Larsen T, Sklenář F, Mahakarnchanakul W, Samson R, Houbraken J. Taxonomy of Aspergillus section Flavi and their production of aflatoxins, ochratoxins and other mycotoxins. Stud Mycol 2019; 93:1-63. [PMID: 30108412 PMCID: PMC6080641 DOI: 10.1016/j.simyco.2018.06.001] [Citation(s) in RCA: 270] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aflatoxins and ochratoxins are among the most important mycotoxins of all and producers of both types of mycotoxins are present in Aspergillus section Flavi, albeit never in the same species. Some of the most efficient producers of aflatoxins and ochratoxins have not been described yet. Using a polyphasic approach combining phenotype, physiology, sequence and extrolite data, we describe here eight new species in section Flavi. Phylogenetically, section Flavi is split in eight clades and the section currently contains 33 species. Two species only produce aflatoxin B1 and B2 (A. pseudotamarii and A. togoensis), and 14 species are able to produce aflatoxin B1, B2, G1 and G2: three newly described species A. aflatoxiformans, A. austwickii and A. cerealis in addition to A. arachidicola, A. minisclerotigenes, A. mottae, A. luteovirescens (formerly A. bombycis), A. nomius, A. novoparasiticus, A. parasiticus, A. pseudocaelatus, A. pseudonomius, A. sergii and A. transmontanensis. It is generally accepted that A. flavus is unable to produce type G aflatoxins, but here we report on Korean strains that also produce aflatoxin G1 and G2. One strain of A. bertholletius can produce the immediate aflatoxin precursor 3-O-methylsterigmatocystin, and one strain of Aspergillus sojae and two strains of Aspergillus alliaceus produced versicolorins. Strains of the domesticated forms of A. flavus and A. parasiticus, A. oryzae and A. sojae, respectively, lost their ability to produce aflatoxins, and from the remaining phylogenetically closely related species (belonging to the A. flavus-, A. tamarii-, A. bertholletius- and A. nomius-clades), only A. caelatus, A. subflavus and A. tamarii are unable to produce aflatoxins. With exception of A. togoensis in the A. coremiiformis-clade, all species in the phylogenetically more distant clades (A. alliaceus-, A. coremiiformis-, A. leporis- and A. avenaceus-clade) are unable to produce aflatoxins. Three out of the four species in the A. alliaceus-clade can produce the mycotoxin ochratoxin A: A. alliaceus s. str. and two new species described here as A. neoalliaceus and A. vandermerwei. Eight species produced the mycotoxin tenuazonic acid: A. bertholletius, A. caelatus, A. luteovirescens, A. nomius, A. pseudocaelatus, A. pseudonomius, A. pseudotamarii and A. tamarii while the related mycotoxin cyclopiazonic acid was produced by 13 species: A. aflatoxiformans, A. austwickii, A. bertholletius, A. cerealis, A. flavus, A. minisclerotigenes, A. mottae, A. oryzae, A. pipericola, A. pseudocaelatus, A. pseudotamarii, A. sergii and A. tamarii. Furthermore, A. hancockii produced speradine A, a compound related to cyclopiazonic acid. Selected A. aflatoxiformans, A. austwickii, A. cerealis, A. flavus, A. minisclerotigenes, A. pipericola and A. sergii strains produced small sclerotia containing the mycotoxin aflatrem. Kojic acid has been found in all species in section Flavi, except A. avenaceus and A. coremiiformis. Only six species in the section did not produce any known mycotoxins: A. aspearensis, A. coremiiformis, A. lanosus, A. leporis, A. sojae and A. subflavus. An overview of other small molecule extrolites produced in Aspergillus section Flavi is given.
Collapse
Affiliation(s)
- J.C. Frisvad
- Department of Biotechnology and Biomedicine, DTU-Bioengineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - V. Hubka
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, 128 01 Prague 2, Czech Republic
- Institute of Microbiology of the CAS, v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - C.N. Ezekiel
- Department of Microbiology, Babcock University, Ilishan Rémo, Nigeria
| | - S.-B. Hong
- Korean Agricultural Culture Collection, National Academy of Agricultural Science, RDA, Suwon, South Korea
| | - A. Nováková
- Institute of Microbiology of the CAS, v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - A.J. Chen
- Institute of Medical Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, PR China
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - M. Arzanlou
- Department of Plant Protection, University of Tabriz, Tabriz, Iran
| | - T.O. Larsen
- Department of Biotechnology and Biomedicine, DTU-Bioengineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - F. Sklenář
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, 128 01 Prague 2, Czech Republic
- Institute of Microbiology of the CAS, v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - W. Mahakarnchanakul
- Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand
| | - R.A. Samson
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - J. Houbraken
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| |
Collapse
|
15
|
Hubka V, Barrs V, Dudová Z, Sklenář F, Kubátová A, Matsuzawa T, Yaguchi T, Horie Y, Nováková A, Frisvad J, Talbot J, Kolařík M. Unravelling species boundaries in the Aspergillus viridinutans complex (section Fumigati): opportunistic human and animal pathogens capable of interspecific hybridization. PERSOONIA 2018; 41:142-174. [PMID: 30728603 PMCID: PMC6344812 DOI: 10.3767/persoonia.2018.41.08] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 03/14/2018] [Indexed: 12/13/2022]
Abstract
Although Aspergillus fumigatus is the major agent of invasive aspergillosis, an increasing number of infections are caused by its cryptic species, especially A. lentulus and the A. viridinutans species complex (AVSC). Their identification is clinically relevant because of antifungal drug resistance and refractory infections. Species boundaries in the AVSC are unresolved since most species have uniform morphology and produce interspecific hybrids in vitro. Clinical and environmental strains from six continents (n = 110) were characterized by DNA sequencing of four to six loci. Biological compatibilities were tested within and between major phylogenetic clades, and ascospore morphology was characterised. Species delimitation methods based on the multispecies coalescent model (MSC) supported recognition of ten species including one new species. Four species are confirmed opportunistic pathogens; A. udagawae followed by A. felis and A. pseudoviridinutans are known from opportunistic human infections, while A. felis followed by A. udagawae and A. wyomingensis are agents of feline sino-orbital aspergillosis. Recently described human-pathogenic species A. parafelis and A. pseudofelis are synonymized with A. felis and an epitype is designated for A. udagawae. Intraspecific mating assay showed that only a few of the heterothallic species can readily generate sexual morphs in vitro. Interspecific mating assays revealed that five different species combinations were biologically compatible. Hybrid ascospores had atypical surface ornamentation and significantly different dimensions compared to parental species. This suggests that species limits in the AVSC are maintained by both pre- and post-zygotic barriers and these species display a great potential for rapid adaptation and modulation of virulence. This study highlights that a sufficient number of strains representing genetic diversity within a species is essential for meaningful species boundaries delimitation in cryptic species complexes. MSC-based delimitation methods are robust and suitable tools for evaluation of boundaries between these species.
Collapse
Affiliation(s)
- V. Hubka
- Department of Botany, Faculty of Science, Charles University, Benátská 2, 128 01 Prague 2, Czech Republic
- Laboratory of Fungal Genetics and Metabolism, Institute of Microbiology of the CAS, v.v.i, Vídeňská 1083, 142 20 Prague 4, Czech Republic
- First Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague 2, Czech Republic
| | - V. Barrs
- Sydney School of Veterinary Science, Faculty of Science, and Marie Bashir Institute of Infectious Diseases & Biosecurity, University of Sydney, Camperdown, NSW, Australia
| | - Z. Dudová
- Department of Botany, Faculty of Science, Charles University, Benátská 2, 128 01 Prague 2, Czech Republic
- First Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague 2, Czech Republic
| | - F. Sklenář
- Department of Botany, Faculty of Science, Charles University, Benátská 2, 128 01 Prague 2, Czech Republic
- Laboratory of Fungal Genetics and Metabolism, Institute of Microbiology of the CAS, v.v.i, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - A. Kubátová
- Department of Botany, Faculty of Science, Charles University, Benátská 2, 128 01 Prague 2, Czech Republic
| | - T. Matsuzawa
- University of Nagasaki, 1-1-1 Manabino, Nagayo-cho, Nishi-Sonogi-gun, Nagasaki 851-2195, Japan
| | - T. Yaguchi
- Medical Mycology Research Center, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8673, Japan
| | - Y. Horie
- Medical Mycology Research Center, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8673, Japan
| | - A. Nováková
- Laboratory of Fungal Genetics and Metabolism, Institute of Microbiology of the CAS, v.v.i, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - J.C. Frisvad
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - J.J. Talbot
- Sydney School of Veterinary Science, Faculty of Science, and Marie Bashir Institute of Infectious Diseases & Biosecurity, University of Sydney, Camperdown, NSW, Australia
| | - M. Kolařík
- Laboratory of Fungal Genetics and Metabolism, Institute of Microbiology of the CAS, v.v.i, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| |
Collapse
|
16
|
Jeyaramraja P, Meenakshi SN, Woldesenbet F. Relationship between drought and preharvest aflatoxin contamination in groundnut (Arachis hypogaea L.). WORLD MYCOTOXIN J 2018. [DOI: 10.3920/wmj2017.2248] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Groundnut is a commercial oilseed crop that is prone to infection by Aspergillus flavus or Aspergillus parasiticus. Drought impairs the defence mechanism of the plant and favours the production of aflatoxin by the fungus. Aflatoxin is a carcinogen and its presence in food and feed causes significant economic loss. The answer to the question, ‘how drought tolerance and aflatoxin resistance are related?’ is not clear. In this review paper, the relationship of drought and preharvest aflatoxin contamination (AC), the relationship of drought tolerance traits and AC, and the approaches to enhance resistance to AC are discussed using up-to-date literature. Factors leading to AC are drought, high geocarposphere temperature, kernel/pod damage, and reduced phytoalexin synthesis by the plant. If the fungus colonises a kernel with reduced water activity, the plant cannot synthesise phytoalexin and then, the fungus synthesises aflatoxin. Breeding for resistance to AC is complicated because aflatoxin concentration is costly to measure, highly variable, and influenced by the environment. Since drought tolerant cultivars have resistance to AC, traits of drought tolerance have been used as indirect selection tools for reduced AC. The genetics of aflatoxin resistance mechanisms have not been made clear as the environment influences the host-pathogen relationship. Host-pathogen interactions under the influence of environment should be studied at molecular level to identify plant resistant factors using the tools of genomics, proteomics, and metabolomics in order to develop cultivars with durable resistance. Many candidate genes involved in host-pathogen interactions have been identified due to improvements in fungal expressed sequence tags, microarrays, and genome sequencing techniques. Moreover, research projects are underway on identifying genes coding for antifungal compounds, resistance associated proteins and quantitative trait loci associated with aflatoxin resistance. This review is expected to help those who wish to work on reducing AC in groundnuts.
Collapse
Affiliation(s)
- P.R. Jeyaramraja
- Department of Biology, College of Natural Sciences, Arba Minch University, P.O. Box 21, Arba Minch, Gamo Gofa Zone, Ethiopia
| | - S. Nithya Meenakshi
- Department of Botany, PSGR Krishnammal College for Women, Peelamedu, Coimbatore 641 004, Tamilnadu, India
| | - F. Woldesenbet
- Department of Biology, College of Natural Sciences, Arba Minch University, P.O. Box 21, Arba Minch, Gamo Gofa Zone, Ethiopia
| |
Collapse
|
17
|
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.
Collapse
|
18
|
Carvajal-Campos A, Manizan AL, Tadrist S, Akaki DK, Koffi-Nevry R, Moore GG, Fapohunda SO, Bailly S, Montet D, Oswald IP, Lorber S, Brabet C, Puel O. Aspergillus korhogoensis, a Novel Aflatoxin Producing Species from the Côte d'Ivoire. Toxins (Basel) 2017; 9:E353. [PMID: 29088078 PMCID: PMC5705968 DOI: 10.3390/toxins9110353] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 10/13/2017] [Accepted: 10/26/2017] [Indexed: 12/12/2022] Open
Abstract
Several strains of a new aflatoxigenic species of Aspergillus, A. korhogoensis, were isolated in the course of a screening study involving species from section Flavi found contaminating peanuts (Arachis hypogaea) and peanut paste in the Côte d'Ivoire. Based on examination of four isolates, this new species is described using a polyphasic approach. A concatenated alignment comprised of nine genes (ITS, benA, cmdA, mcm7, amdS, rpb1, preB, ppgA, and preA) was subjected to phylogenetic analysis, and resulted in all four strains being inferred as a distinct clade. Characterization of mating type for each strain revealed A. korhogoensis as a heterothallic species, since three isolates exhibited a singular MAT1-1 locus and one isolate exhibited a singular MAT1-2 locus. Morphological and physiological characterizations were also performed based on their growth on various types of media. Their respective extrolite profiles were characterized using LC/HRMS, and showed that this new species is capable of producing B- and G-aflatoxins, aspergillic acid, cyclopiazonic acid, aflavarins, and asparasones, as well as other metabolites. Altogether, our results confirm the monophyly of A. korhogoensis, and strengthen its position in the A. flavus clade, as the sister taxon of A. parvisclerotigenus.
Collapse
Affiliation(s)
- Amaranta Carvajal-Campos
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Ama Lethicia Manizan
- Laboratoire de Biotechnologie et Microbiologie des Aliments, UFR des Sciences et Technologie des Aliments, Université Nangui Abrogoua, 02 BP 801 Abidjan, Côte d'Ivoire.
| | - Souria Tadrist
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - David Koffi Akaki
- Laboratoire des Procédés Industriels de Synthèse, de l'Environnement et des Energies Nouvelles, Département Génie Chimique et Agro-alimentaire, Institut National Polytechnique Félix Houphouët-Boigny, BP 1313 Yamoussoukro, Côte d'Ivoire.
| | - Rose Koffi-Nevry
- Laboratoire de Biotechnologie et Microbiologie des Aliments, UFR des Sciences et Technologie des Aliments, Université Nangui Abrogoua, 02 BP 801 Abidjan, Côte d'Ivoire.
| | - Geromy G Moore
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, New Orleans, LA 70179, USA.
| | - Stephen O Fapohunda
- Department of Microbiology, Babcock University, 23401 Ilishan Remo, Nigeria.
| | - Sylviane Bailly
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Didier Montet
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD)-Département PERSYST-UMR QualiSud, 34398 Montpellier, France.
| | - Isabelle P Oswald
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Sophie Lorber
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Catherine Brabet
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD)-Département PERSYST-UMR QualiSud, 34398 Montpellier, France.
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| |
Collapse
|
19
|
Moore GG, Olarte RA, Horn BW, Elliott JL, Singh R, O'Neal CJ, Carbone I. Global population structure and adaptive evolution of aflatoxin-producing fungi. Ecol Evol 2017; 7:9179-9191. [PMID: 29152206 PMCID: PMC5677503 DOI: 10.1002/ece3.3464] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 07/28/2017] [Accepted: 08/31/2017] [Indexed: 12/16/2022] Open
Abstract
Aflatoxins produced by several species in Aspergillus section Flavi are a significant problem in agriculture and a continuous threat to human health. To provide insights into the biology and global population structure of species in section Flavi, a total of 1,304 isolates were sampled across six species (A. flavus, A. parasiticus, A. nomius, A. caelatus, A. tamarii, and A. alliaceus) from single fields in major peanut‐growing regions in Georgia (USA), Australia, Argentina, India, and Benin (Africa). We inferred maximum‐likelihood phylogenies for six loci, both combined and separately, including two aflatoxin cluster regions (aflM/alfN and aflW/aflX) and four noncluster regions (amdS, trpC, mfs and MAT), to examine population structure and history. We also employed principal component and STRUCTURE analysis to identify genetic clusters and their associations with six different categories (geography, species, precipitation, temperature, aflatoxin chemotype profile, and mating type). Overall, seven distinct genetic clusters were inferred, some of which were more strongly structured by G chemotype diversity than geography. Populations of A. flavus S in Benin were genetically distinct from all other section Flavi species for the loci examined, which suggests genetic isolation. Evidence of trans‐speciation within two noncluster regions, whereby A. flavus SBG strains from Australia share haplotypes with either A. flavus or A. parasiticus, was observed. Finally, while clay soil and precipitation may influence species richness in Aspergillus section Flavi, other region‐specific environmental and genetic parameters must also be considered.
Collapse
Affiliation(s)
- Geromy G Moore
- Southern Regional Research Center Agricultural Research Service U.S. Department of Agriculture New Orleans LA USA
| | - Rodrigo A Olarte
- Department of Plant Biology University of Minnesota St. Paul MN USA
| | - Bruce W Horn
- Department of Agriculture Agricultural Research Service National Peanut Research Laboratory Dawson GA USA
| | - Jacalyn L Elliott
- Department of Entomology and Plant Pathology Center for Integrated Fungal Research North Carolina State University Raleigh NC USA
| | - Rakhi Singh
- Department of Entomology and Plant Pathology Center for Integrated Fungal Research North Carolina State University Raleigh NC USA
| | - Carolyn J O'Neal
- Department of Entomology and Plant Pathology Center for Integrated Fungal Research North Carolina State University Raleigh NC USA
| | - Ignazio Carbone
- Department of Entomology and Plant Pathology Center for Integrated Fungal Research North Carolina State University Raleigh NC USA
| |
Collapse
|
20
|
Abstract
Xerophilic fungi, especially Aspergillus species, are prevalent in the built environment. In this study, we employed a combined culture-independent (454-pyrosequencing) and culture-dependent (dilution-to-extinction) approach to investigate the mycobiota of indoor dust collected from 93 buildings in 12 countries worldwide. High and low water activity (aw) media were used to capture mesophile and xerophile biodiversity, resulting in the isolation of approximately 9 000 strains. Among these, 340 strains representing seven putative species in Aspergillus subgenus Polypaecilum were isolated, mostly from lowered aw media, and tentatively identified based on colony morphology and internal transcribed spacer rDNA region (ITS) barcodes. Further morphological study and phylogenetic analyses using sequences of ITS, β-tubulin (BenA), calmodulin (CaM), RNA polymerase II second largest subunit (RPB2), DNA topoisomerase 1 (TOP1), and a pre-mRNA processing protein homolog (TSR1) confirmed the isolation of seven species of subgenus Polypaecilum, including five novel species: A. baarnensis, A. keratitidis, A. kalimae sp. nov., A. noonimiae sp. nov., A. thailandensis sp. nov., A. waynelawii sp. nov., and A. whitfieldii sp. nov. Pyrosequencing detected six of the seven species isolated from house dust, as well as one additional species absent from the cultures isolated, and three clades representing potentially undescribed species. Species were typically found in house dust from subtropical and tropical climates, often in close proximity to the ocean or sea. The presence of subgenus Polypaecilum, a recently described clade of xerophilic/xerotolerant, halotolerant/halophilic, and potentially zoopathogenic species, within the built environment is noteworthy.
Collapse
Affiliation(s)
- J.B. Tanney
- Ottawa Research and Development Centre, Biodiversity (Mycology and Microbiology), Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario K1A 0C6, Canada
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec G1V 0A6, Canada
| | - C.M. Visagie
- Ottawa Research and Development Centre, Biodiversity (Mycology and Microbiology), Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario K1A 0C6, Canada
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada
- Biosystematics Division, ARC-Plant Health and Protection, P/BagX134, Queenswood, 0121 Pretoria, South Africa
| | - N. Yilmaz
- Ottawa Research and Development Centre, Biodiversity (Mycology and Microbiology), Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario K1A 0C6, Canada
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada
| | - K.A. Seifert
- Ottawa Research and Development Centre, Biodiversity (Mycology and Microbiology), Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario K1A 0C6, Canada
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada
| |
Collapse
|
21
|
Faustinelli PC, Palencia ER, Sobolev VS, Horn BW, Sheppard HT, Lamb MC, Wang XM, Scheffler BE, Martinez Castillo J, Arias RS. Study of the genetic diversity of the aflatoxin biosynthesis cluster in Aspergillus section Flavi using insertion/deletion markers in peanut seeds from Georgia, USA. Mycologia 2017; 109:200-209. [PMID: 28506119 DOI: 10.1080/00275514.2017.1307095] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Aflatoxins are among the most powerful carcinogens in nature. The major aflatoxin-producing fungi are Aspergillus flavus and A. parasiticus. Numerous crops, including peanut, are susceptible to aflatoxin contamination by these fungi. There has been an increased use of RNA interference (RNAi) technology to control phytopathogenic fungi in recent years. In order to develop molecular tools targeting specific genes of these fungi for the control of aflatoxins, it is necessary to obtain their genome sequences. Although high-throughput sequencing is readily available, it is still impractical to sequence the genome of every isolate. Thus, in this work, the authors proposed a workflow that allowed prescreening of 238 Aspergillus section Flavi isolates from peanut seeds from Georgia, USA. The aflatoxin biosynthesis cluster (ABC) of the isolates was fingerprinted at 25 InDel (insertion/deletion) loci using capillary electrophoresis. All isolates were tested for aflatoxins using ultra-high-performance liquid chromatography. The neighbor-joining, three-dimension (3D) principal coordinate, and Structure analyses revealed that the Aspergillus isolates sampled consisted of three main groups determined by their capability to produce aflatoxins. Group I comprised 10 non-aflatoxigenic A. flavus; Group II included A. parasiticus; and Group III included mostly aflatoxigenic A. flavus and the three non-aflatoxigenic A. caelatus. Whole genomes of 10 representative isolates from different groups were sequenced. Although InDels in Aspergillus have been used by other research groups, this is the first time that the cluster analysis resulting from fingerprinting was followed by whole-genome sequencing of representative isolates. In our study, cluster analysis of ABC sequences validated the results obtained with fingerprinting. This shows that InDels used here can predict similarities at the genome level. Our results also revealed a relationship between groups and their capability to produce aflatoxins. The database generated of Aspergillus spp. can be used to select target genes and assess the effectiveness of RNAi technology to reduce aflatoxin contamination in peanut.
Collapse
Affiliation(s)
- Paola C Faustinelli
- a National Peanut Research Laboratory, Agricultural Research Service , United States Department of Agriculture , 1011 Forrester Drive S.E., Dawson , Georgia 39842-0509
| | - Edwin R Palencia
- a National Peanut Research Laboratory, Agricultural Research Service , United States Department of Agriculture , 1011 Forrester Drive S.E., Dawson , Georgia 39842-0509
| | - Victor S Sobolev
- a National Peanut Research Laboratory, Agricultural Research Service , United States Department of Agriculture , 1011 Forrester Drive S.E., Dawson , Georgia 39842-0509
| | - Bruce W Horn
- a National Peanut Research Laboratory, Agricultural Research Service , United States Department of Agriculture , 1011 Forrester Drive S.E., Dawson , Georgia 39842-0509
| | - Hank T Sheppard
- a National Peanut Research Laboratory, Agricultural Research Service , United States Department of Agriculture , 1011 Forrester Drive S.E., Dawson , Georgia 39842-0509
| | - Marshall C Lamb
- a National Peanut Research Laboratory, Agricultural Research Service , United States Department of Agriculture , 1011 Forrester Drive S.E., Dawson , Georgia 39842-0509
| | - Xinye M Wang
- a National Peanut Research Laboratory, Agricultural Research Service , United States Department of Agriculture , 1011 Forrester Drive S.E., Dawson , Georgia 39842-0509
| | - Brian E Scheffler
- b Genomics and Bioinformatics Research Unit, Agricultural Research Service , United States Department of Agriculture , 141 Experiment Station Road, Stoneville , Mississippi 38776
| | - Jaime Martinez Castillo
- c Centro de Investigación Científica de Yucatán , A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida , Yucatán 97200 , México
| | - Renée S Arias
- a National Peanut Research Laboratory, Agricultural Research Service , United States Department of Agriculture , 1011 Forrester Drive S.E., Dawson , Georgia 39842-0509
| |
Collapse
|
22
|
Paulussen C, Hallsworth JE, Álvarez‐Pérez S, Nierman WC, Hamill PG, Blain D, Rediers H, Lievens B. Ecology of aspergillosis: insights into the pathogenic potency of Aspergillus fumigatus and some other Aspergillus species. Microb Biotechnol 2017; 10:296-322. [PMID: 27273822 PMCID: PMC5328810 DOI: 10.1111/1751-7915.12367] [Citation(s) in RCA: 179] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 04/08/2016] [Accepted: 04/18/2016] [Indexed: 01/26/2023] Open
Abstract
Fungi of the genus Aspergillus are widespread in the environment. Some Aspergillus species, most commonly Aspergillus fumigatus, may lead to a variety of allergic reactions and life-threatening systemic infections in humans. Invasive aspergillosis occurs primarily in patients with severe immunodeficiency, and has dramatically increased in recent years. There are several factors at play that contribute to aspergillosis, including both fungus and host-related factors such as strain virulence and host pulmonary structure/immune status, respectively. The environmental tenacity of Aspergilllus, its dominance in diverse microbial communities/habitats, and its ability to navigate the ecophysiological and biophysical challenges of host infection are attributable, in large part, to a robust stress-tolerance biology and exceptional capacity to generate cell-available energy. Aspects of its stress metabolism, ecology, interactions with diverse animal hosts, clinical presentations and treatment regimens have been well-studied over the past years. Here, we synthesize these findings in relation to the way in which some Aspergillus species have become successful opportunistic pathogens of human- and other animal hosts. We focus on the biophysical capabilities of Aspergillus pathogens, key aspects of their ecophysiology and the flexibility to undergo a sexual cycle or form cryptic species. Additionally, recent advances in diagnosis of the disease are discussed as well as implications in relation to questions that have yet to be resolved.
Collapse
Affiliation(s)
- Caroline Paulussen
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM)Department of Microbial and Molecular Systems (M2S)KU LeuvenCampus De NayerSint‐Katelijne‐WaverB‐2860Belgium
| | - John E. Hallsworth
- Institute for Global Food SecuritySchool of Biological SciencesMedical Biology CentreQueen's University BelfastBelfastBT9 7BLUK
| | - Sergio Álvarez‐Pérez
- Faculty of Veterinary MedicineDepartment of Animal HealthUniversidad Complutense de MadridMadridE‐28040Spain
| | | | - Philip G. Hamill
- Institute for Global Food SecuritySchool of Biological SciencesMedical Biology CentreQueen's University BelfastBelfastBT9 7BLUK
| | - David Blain
- Institute for Global Food SecuritySchool of Biological SciencesMedical Biology CentreQueen's University BelfastBelfastBT9 7BLUK
| | - Hans Rediers
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM)Department of Microbial and Molecular Systems (M2S)KU LeuvenCampus De NayerSint‐Katelijne‐WaverB‐2860Belgium
| | - Bart Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM)Department of Microbial and Molecular Systems (M2S)KU LeuvenCampus De NayerSint‐Katelijne‐WaverB‐2860Belgium
| |
Collapse
|
23
|
Genome Sequences of Eight Aspergillus flavus spp. and One A. parasiticus sp., Isolated from Peanut Seeds in Georgia. GENOME ANNOUNCEMENTS 2016; 4:4/2/e00278-16. [PMID: 27081142 PMCID: PMC4832170 DOI: 10.1128/genomea.00278-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Aspergillus flavus and A. parasiticus fungi produce carcinogenic mycotoxins in peanut seeds, causing considerable impact on both human health and the economy. Here, we report nine genome sequences of Aspergillus spp., isolated from Georgia peanut seeds in 2014. The information obtained will lead to further biodiversity studies that are essential for developing control strategies.
Collapse
|
24
|
Mating type markers reveal high levels of heterothallism in Leptographium sensu lato. Fungal Biol 2016; 120:538-546. [PMID: 27020155 DOI: 10.1016/j.funbio.2016.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 12/23/2015] [Accepted: 01/03/2016] [Indexed: 01/16/2023]
Abstract
Species of Leptographium sensu lato are sap-stain fungi vectored by bark beetles and some species cause or are associated with tree diseases. Sexual states have been reported for more than 30 species in this group and these have been treated in the sexual genus Grosmannia. No sexual state is known for at least 59 additional species and these reside in the genus Leptographium. The discovery of sexual states for species of Leptographium relies mainly on the presence of fruiting bodies on host tissue at the time of isolation and/or intensive laboratory mating studies, which commonly have low levels of success. We developed mating-type markers to study sexual compatibility of species in Leptographium sensu lato. Using these markers, it was possible to identify mating types for 42 species and to determine thallism in many species for the first time. Surprisingly, the results showed that heterothallic and putatively heterothallic species are abundant (39 out of 42 species) in Leptographium sensu lato, and only three species were confirmed to be homothallic. The mating type markers developed in this study will be useful for future studies concerning mating type and sexual compatibility of species in this genus.
Collapse
|
25
|
Hove M, Van Poucke C, Njumbe-Ediage E, Nyanga L, De Saeger S. Review on the natural co-occurrence of AFB1 and FB1 in maize and the combined toxicity of AFB1 and FB1. Food Control 2016. [DOI: 10.1016/j.foodcont.2015.06.053] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
26
|
Nakamura H, Kikuma T, Jin FJ, Maruyama JI, Kitamoto K. AoRim15 is involved in conidial stress tolerance, conidiation and sclerotia formation in the filamentous fungus Aspergillus oryzae. J Biosci Bioeng 2015; 121:365-71. [PMID: 26467693 DOI: 10.1016/j.jbiosc.2015.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 08/12/2015] [Accepted: 08/18/2015] [Indexed: 12/11/2022]
Abstract
The serine-threonine kinase Rim15p is a master regulator of stress signaling and is required for stress tolerance and sexual sporulation in the yeast Saccharomyces cerevisiae. However, in filamentous fungi that reproduce asexually via conidiation, the physiological function of Rim15p homologs has not been extensively analyzed. Here, we functionally characterized the protein homolog of Rim15p in the filamentous fungus Aspergillus oryzae, by deleting and overexpressing the corresponding Aorim15 gene and examining the role of this protein in stress tolerance and development. Deletion of Aorim15 resulted in an increase in the sensitivity of conidia to oxidative and heat stresses, whereas conidia of the Aorim15 overexpressing strain were more resistant to these stresses. These results indicated that AoRim15 functions in stress tolerance, similar to S. cerevisiae Rim15p. Phenotypic analysis revealed that conidiation was markedly reduced by overexpression of Aorim15 in A. oryzae, and was completely abolished in the deletion strain. In addition, the formation of sclerotia, which is another type of developmental structure in filamentous fungi, was decreased by the deletion of Aorim15, whereas Aorim15 overexpression increased the number of sclerotia. These results indicated that AoRim15 is a positive regulator of sclerotia formation and that overexpression of AoRim15 shifts the developmental balance from conidiation towards sclerotia formation. Collectively, we demonstrated that AoRim15 is involved in the stress tolerance of conidia and differentially regulates between the two developmental fates of conidiation and sclerotia formation.
Collapse
Affiliation(s)
- Hidetoshi Nakamura
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Takashi Kikuma
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Feng Jie Jin
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Jun-ichi Maruyama
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
| | - Katsuhiko Kitamoto
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| |
Collapse
|
27
|
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]
|
28
|
Resistance to Aspergillus flavus in maize and peanut: Molecular biology, breeding, environmental stress, and future perspectives. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.cj.2015.02.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
29
|
Olarte RA, Worthington CJ, Horn BW, Moore GG, Singh R, Monacell JT, Dorner JW, Stone EA, Xie DY, Carbone I. Enhanced diversity and aflatoxigenicity in interspecific hybrids ofAspergillus flavusandAspergillus parasiticus. Mol Ecol 2015; 24:1889-909. [DOI: 10.1111/mec.13153] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 03/07/2015] [Accepted: 03/11/2015] [Indexed: 12/23/2022]
Affiliation(s)
- Rodrigo A. Olarte
- Center for Integrated Fungal Research; Department of Plant Pathology; North Carolina State University; Raleigh NC 27695 USA
| | - Carolyn J. Worthington
- Center for Integrated Fungal Research; Department of Plant Pathology; North Carolina State University; Raleigh NC 27695 USA
| | - Bruce W. Horn
- National Peanut Research Laboratory; Agricultural Research Service; U.S. Department of Agriculture; Dawson GA 39842 USA
| | - Geromy G. Moore
- Southern Regional Research Center; Agricultural Research Service; U.S. Department of Agriculture; New Orleans LA 70179 USA
| | - Rakhi Singh
- Center for Integrated Fungal Research; Department of Plant Pathology; North Carolina State University; Raleigh NC 27695 USA
| | - James T. Monacell
- Center for Integrated Fungal Research; Department of Plant Pathology; North Carolina State University; Raleigh NC 27695 USA
- Bioinformatics Research Center; North Carolina State University; Raleigh NC 27695 USA
| | - Joe W. Dorner
- National Peanut Research Laboratory; Agricultural Research Service; U.S. Department of Agriculture; Dawson GA 39842 USA
| | - Eric A. Stone
- Bioinformatics Research Center; North Carolina State University; Raleigh NC 27695 USA
- Department of Biological Sciences; North Carolina State University; Raleigh NC 27695 USA
| | - De-Yu Xie
- Department of Plant and Microbial Biology; North Carolina State University; Raleigh NC 27695 USA
| | - Ignazio Carbone
- Center for Integrated Fungal Research; Department of Plant Pathology; North Carolina State University; Raleigh NC 27695 USA
- Bioinformatics Research Center; North Carolina State University; Raleigh NC 27695 USA
| |
Collapse
|
30
|
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.
Collapse
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
| |
Collapse
|
31
|
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.
Collapse
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
| |
Collapse
|
32
|
|
33
|
Abstract
Field inoculation with non-aflatoxigenic Aspergillus flavus is a preferred method for pre-harvest biocontrol of aflatoxin contamination of maize, cottonseed, and groundnut. Rationale for using these A. flavus strains is that they (1) maintain persistent control of aflatoxigenic fungi in the field, and (2) are incapable of out-crossing. Trackable field-released biocontrol strains will be beneficial to study the movement and longevity of non-aflatoxigenic A. flavus strains. Incorporating a naturally-occurring compound such as enhanced green fluorescent protein (eGFP) into a biocontrol strain might allow observation of its behaviour in field settings. The success of long-term field testing of eGFP-expressing A. flavus strains depends on their ability to maintain fluorescence throughout growth. Additionally, to ensure accurate tracking of the fluorescent atoxigenic strain, the likelihood of their out-crossing with individuals from the native population must be determined. In vitro mating experiments paired each of six different eGFP-transformed atoxigenic strains with a highly fertile toxigenic A. flavus isolate. Findings indicate that the eGFP gene, and possibly the aflatoxin cluster, is heritable by the F1 progeny. Not all cultured ascospores were fluorescent, but subsequent growth arising from a single fluorescent ascospore exhibited fluorescence similar to the eGFP parent. Observed mixed-fluorescence among conidia in a single chain suggests heterokaryosis at the moment of conidiogenesis. Mycotoxin assays showed that some fluorescent F1 individuals produce aflatoxin and/or cyclopiazonic acid which would indicate they are recombinant offspring. The findings in this laboratory study lend support to concern that atoxigenic strains are not impervious to genetic recombination and for which, if possible in a natural environment, repeated use could pose a risk of increasing the occurrence of aflatoxigenic individuals in treated fields.
Collapse
Affiliation(s)
- G.G. Moore
- Southern Regional Research Center, Agricultural Research Service, SDA, 1100 Robert E. Lee Blvd, New Orleans, LA 70124, USA
| |
Collapse
|
34
|
Baidya S, Duran RM, Lohmar JM, Harris-Coward PY, Cary JW, Hong SY, Roze LV, Linz JE, Calvo AM. VeA is associated with the response to oxidative stress in the aflatoxin producer Aspergillus flavus. EUKARYOTIC CELL 2014; 13:1095-103. [PMID: 24951443 PMCID: PMC4135802 DOI: 10.1128/ec.00099-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 06/14/2014] [Indexed: 12/20/2022]
Abstract
Survival of fungal species depends on the ability of these organisms to respond to environmental stresses. Osmotic stress or high levels of reactive oxygen species (ROS) can cause stress in fungi resulting in growth inhibition. Both eukaryotic and prokaryotic cells have developed numerous mechanisms to counteract and survive the stress in the presence of ROS. In many fungi, the HOG signaling pathway is crucial for the oxidative stress response as well as for osmotic stress response. This study revealed that while the osmotic stress response is only slightly affected by the master regulator veA, this gene, also known to control morphological development and secondary metabolism in numerous fungal species, has a profound effect on the oxidative stress response in the aflatoxin-producing fungus Aspergillus flavus. We found that the expression of A. flavus homolog genes involved in the HOG signaling pathway is regulated by veA. Deletion of veA resulted in a reduction in transcription levels of oxidative stress response genes after exposure to hydrogen peroxide. Furthermore, analyses of the effect of VeA on the promoters of cat1 and trxB indicate that the presence of VeA alters DNA-protein complex formation. This is particularly notable in the cat1 promoter, where the absence of VeA results in abnormally stronger complex formation with reduced cat1 expression and more sensitivity to ROS in a veA deletion mutant, suggesting that VeA might prevent binding of negative transcription regulators to the cat1 promoter. Our study also revealed that veA positively influences the expression of the transcription factor gene atfB and that normal formation of DNA-protein complexes in the cat1 promoter is dependent on AtfB.
Collapse
Affiliation(s)
- Sachin Baidya
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, USA
| | - Rocio M Duran
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, USA
| | - Jessica M Lohmar
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, USA
| | - Pamela Y Harris-Coward
- Southern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, New Orleans, Louisiana, USA
| | - Jeffrey W Cary
- Southern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, New Orleans, Louisiana, USA
| | - Sung-Yong Hong
- Department of Food Science and Human Nutrition, Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Ludmila V Roze
- Department of Food Science and Human Nutrition, Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - John E Linz
- Department of Food Science and Human Nutrition, Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Ana M Calvo
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, USA
| |
Collapse
|
35
|
Houbraken J, de Vries RP, Samson RA. Modern taxonomy of biotechnologically important Aspergillus and Penicillium species. ADVANCES IN APPLIED MICROBIOLOGY 2014; 86:199-249. [PMID: 24377856 DOI: 10.1016/b978-0-12-800262-9.00004-4] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Taxonomy is a dynamic discipline and name changes of fungi with biotechnological, industrial, or medical importance are often difficult to understand for researchers in the applied field. Species belonging to the genera Aspergillus and Penicillium are commonly used or isolated, and inadequate taxonomy or uncertain nomenclature of these genera can therefore lead to tremendous confusion. Misidentification of strains used in biotechnology can be traced back to (1) recent changes in nomenclature, (2) new taxonomic insights, including description of new species, and/or (3) incorrect identifications. Changes in the recent published International Code of Nomenclature for Algae, Fungi and Plants will lead to numerous name changes of existing Aspergillus and Penicillium species and an overview of the current names of biotechnological important species is given. Furthermore, in (biotechnological) literature old and invalid names are still used, such as Aspergillus awamori, A. foetidus, A. kawachii, Talaromyces emersonii, Acremonium cellulolyticus, and Penicillium funiculosum. An overview of these and other species with their correct names is presented. Furthermore, the biotechnologically important species Talaromyces thermophilus is here combined in Thermomyces as Th. dupontii. The importance of Aspergillus, Penicillium, and related genera is also illustrated by the high number of undertaken genome sequencing projects. A number of these strains are incorrectly identified or atypical strains are selected for these projects. Recommendations for correct strain selection are given here. Phylogenetic analysis shows a close relationship between the genome-sequenced strains of Aspergillus, Penicillium, and Monascus. Talaromyces stipitatus and T. marneffei (syn. Penicillium marneffei) are closely related to Thermomyces lanuginosus and Th. dupontii (syn. Talaromyces thermophilus), and these species appear to be distantly related to Aspergillus and Penicillium. In the last part of this review, an overview of heterothallic reproduction in Aspergillus and Penicillium is given. The new insights in the taxonomy of Aspergillus, Penicillium, and related genera will help to interpret the results generated with comparative genomics studies or other studies dealing with evolution of, for example, enzymes, mating-type loci, virulence genes, and secondary metabolite biosynthetic gene clusters.
Collapse
Affiliation(s)
- Jos Houbraken
- CBS-KNAW Fungal Biodiversity Centre, Utrecht, The Netherlands.
| | | | - Robert A Samson
- CBS-KNAW Fungal Biodiversity Centre, Utrecht, The Netherlands
| |
Collapse
|
36
|
Abstract
Sexual reproduction is a pervasive attribute of eukaryotic species and is now recognized to occur in many clinically important human fungal pathogens. These fungi use sexual or parasexual strategies for various purposes that can have an impact on pathogenesis, such as the formation of drug-resistant isolates, the generation of strains with increased virulence or the modulation of interactions with host cells. In this Review, we examine the mechanisms regulating fungal sex and the consequences of these programmes for human disease.
Collapse
|
37
|
Frisvad JC, Petersen LM, Lyhne EK, Larsen TO. Formation of sclerotia and production of indoloterpenes by Aspergillus niger and other species in section Nigri. PLoS One 2014; 9:e94857. [PMID: 24736731 PMCID: PMC3988082 DOI: 10.1371/journal.pone.0094857] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 03/19/2014] [Indexed: 01/04/2023] Open
Abstract
Several species in Aspergillus section Nigri have been reported to produce sclerotia on well-known growth media, such as Czapek yeast autolysate (CYA) agar, with sclerotia considered to be an important prerequisite for sexual development. However Aspergillus niger sensu stricto has not been reported to produce sclerotia, and is thought to be a purely asexual organism. Here we report, for the first time, the production of sclerotia by certain strains of Aspergillus niger when grown on CYA agar with raisins, or on other fruits or on rice. Up to 11 apolar indoloterpenes of the aflavinine type were detected by liquid chromatography and diode array and mass spectrometric detection where sclerotia were formed, including 10,23-dihydro-24,25-dehydroaflavinine. Sclerotium induction can thus be a way of inducing the production of new secondary metabolites from previously silent gene clusters. Cultivation of other species of the black aspergilli showed that raisins induced sclerotium formation by A. brasiliensis, A. floridensis A. ibericus, A. luchuensis, A. neoniger, A. trinidadensis and A. saccharolyticus for the first time.
Collapse
Affiliation(s)
- Jens C. Frisvad
- Chemodiversity Group, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
- * E-mail:
| | - Lene M. Petersen
- Chemodiversity Group, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - E. Kirstine Lyhne
- Chemodiversity Group, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Thomas O. Larsen
- Chemodiversity Group, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| |
Collapse
|
38
|
Fountain JC, Scully BT, Ni X, Kemerait RC, Lee RD, Chen ZY, Guo B. Environmental influences on maize-Aspergillus flavus interactions and aflatoxin production. Front Microbiol 2014; 5:40. [PMID: 24550905 PMCID: PMC3913990 DOI: 10.3389/fmicb.2014.00040] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 01/21/2014] [Indexed: 12/25/2022] Open
Abstract
Since the early 1960s, the fungal pathogen Aspergillus flavus (Link ex Fr.) has been the focus of intensive research due to the production of carcinogenic and highly toxic secondary metabolites collectively known as aflatoxins following pre-harvest colonization of crops. Given this recurrent problem and the occurrence of a severe aflatoxin outbreak in maize (Zea mays L.), particularly in the Southeast U.S. in the 1977 growing season, a significant research effort has been put forth to determine the nature of the interaction occurring between aflatoxin production, A. flavus, environment and its various hosts before harvest. Many studies have investigated this interaction at the genetic, transcript, and protein levels, and in terms of fungal biology at either pre- or post-harvest time points. Later experiments have indicated that the interaction and overall resistance phenotype of the host is a quantitative trait with a relatively low heritability. In addition, a high degree of environmental interaction has been noted, particularly with sources of abiotic stress for either the host or the fungus such as drought or heat stresses. Here, we review the history of research into this complex interaction and propose future directions for elucidating the relationship between resistance and susceptibility to A. flavus colonization, abiotic stress, and its relationship to oxidative stress in which aflatoxin production may function as a form of antioxidant protection to the producing fungus.
Collapse
Affiliation(s)
- Jake C. Fountain
- Department of Plant Pathology, University of GeorgiaTifton, GA, USA
| | - Brian T. Scully
- Crop Protection and Management Research Unit, Agricultural Research Service – United States Department of AgricultureTifton, GA, USA
| | - Xinzhi Ni
- Crop Genetics and Breeding Research Unit, Agricultural Research Service – United States Department of AgricultureTifton, GA, USA
| | | | - Robert D. Lee
- Department of Crop and Soil Sciences, University of GeorgiaTifton, GA, USA
| | - Zhi-Yuan Chen
- Department of Plant Pathology and Crop Physiology, Louisiana State UniversityBaton Rouge, LA, USA
| | - Baozhu Guo
- Department of Plant Pathology, University of GeorgiaTifton, GA, USA
- Crop Protection and Management Research Unit, Agricultural Research Service – United States Department of AgricultureTifton, GA, USA
| |
Collapse
|
39
|
Horn BW, Sorensen RB, Lamb MC, Sobolev VS, Olarte RA, Worthington CJ, Carbone I. Sexual reproduction in Aspergillus flavus sclerotia naturally produced in corn. PHYTOPATHOLOGY 2014; 104:75-85. [PMID: 23883157 DOI: 10.1094/phyto-05-13-0129-r] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Aspergillus flavus is the major producer of carcinogenic aflatoxins worldwide in crops. Populations of A. flavus are characterized by high genetic variation and the source of this variation is likely sexual reproduction. The fungus is heterothallic and laboratory crosses produce ascospore-bearing ascocarps embedded within sclerotia. However, the capacity for sexual reproduction in sclerotia naturally formed in crops has not been examined. Corn was grown for 3 years under different levels of drought stress at Shellman, GA, and sclerotia were recovered from 146 ears (0.6% of ears). Sclerotia of A. flavus L strain were dominant in 2010 and 2011 and sclerotia of A. flavus S strain were dominant in 2012. The incidence of S strain sclerotia in corn ears increased with decreasing water availability. Ascocarps were not detected in sclerotia at harvest but incubation of sclerotia on the surface of nonsterile soil in the laboratory resulted in the formation of viable ascospores in A. flavus L and S strains and in homothallic A. alliaceus. Ascospores were produced by section Flavi species in 6.1% of the 6,022 sclerotia (18 of 84 ears) in 2010, 0.1% of the 2,846 sclerotia (3 of 36 ears) in 2011, and 0.5% of the 3,106 sclerotia (5 of 26 ears) in 2012. For sexual reproduction to occur under field conditions, sclerotia may require an additional incubation period on soil following dispersal at crop harvest.
Collapse
|
40
|
Mating type genes and cryptic sexuality as tools for genetically manipulating industrial molds. Appl Microbiol Biotechnol 2013; 97:9609-20. [DOI: 10.1007/s00253-013-5268-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 09/12/2013] [Accepted: 09/14/2013] [Indexed: 01/11/2023]
|
41
|
Moore GG, Elliott JL, Singh R, Horn BW, Dorner JW, Stone EA, Chulze SN, Barros GG, Naik MK, Wright GC, Hell K, Carbone I. Sexuality generates diversity in the aflatoxin gene cluster: evidence on a global scale. PLoS Pathog 2013; 9:e1003574. [PMID: 24009506 PMCID: PMC3757046 DOI: 10.1371/journal.ppat.1003574] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 07/09/2013] [Indexed: 12/24/2022] Open
Abstract
Aflatoxins are produced by Aspergillus flavus and A. parasiticus in oil-rich seed and grain crops and are a serious problem in agriculture, with aflatoxin B₁ being the most carcinogenic natural compound known. Sexual reproduction in these species occurs between individuals belonging to different vegetative compatibility groups (VCGs). We examined natural genetic variation in 758 isolates of A. flavus, A. parasiticus and A. minisclerotigenes sampled from single peanut fields in the United States (Georgia), Africa (Benin), Argentina (Córdoba), Australia (Queensland) and India (Karnataka). Analysis of DNA sequence variation across multiple intergenic regions in the aflatoxin gene clusters of A. flavus, A. parasiticus and A. minisclerotigenes revealed significant linkage disequilibrium (LD) organized into distinct blocks that are conserved across different localities, suggesting that genetic recombination is nonrandom and a global occurrence. To assess the contributions of asexual and sexual reproduction to fixation and maintenance of toxin chemotype diversity in populations from each locality/species, we tested the null hypothesis of an equal number of MAT1-1 and MAT1-2 mating-type individuals, which is indicative of a sexually recombining population. All samples were clone-corrected using multi-locus sequence typing which associates closely with VCG. For both A. flavus and A. parasiticus, when the proportions of MAT1-1 and MAT1-2 were significantly different, there was more extensive LD in the aflatoxin cluster and populations were fixed for specific toxin chemotype classes, either the non-aflatoxigenic class in A. flavus or the B₁-dominant and G₁-dominant classes in A. parasiticus. A mating type ratio close to 1∶1 in A. flavus, A. parasiticus and A. minisclerotigenes was associated with higher recombination rates in the aflatoxin cluster and less pronounced chemotype differences in populations. This work shows that the reproductive nature of the population (more sexual versus more asexual) is predictive of aflatoxin chemotype diversity in these agriculturally important fungi.
Collapse
Affiliation(s)
- Geromy G. Moore
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, New Orleans, Louisiana, United States of America
| | - Jacalyn L. Elliott
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Rakhi Singh
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Bruce W. Horn
- National Peanut Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Dawson, Georgia, United States of America
| | - Joe W. Dorner
- National Peanut Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Dawson, Georgia, United States of America
| | - Eric A. Stone
- Bioinformatics Research Center, North Carolina State University, Raleigh, North Carolina, United States of America
- Department of Genetics, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Sofia N. Chulze
- Departamento de Microbiología e Inmunología, Universidad Nacional de Río Cuarto, Córdoba, Argentina
| | - German G. Barros
- Departamento de Microbiología e Inmunología, Universidad Nacional de Río Cuarto, Córdoba, Argentina
| | - Manjunath K. Naik
- Department of Plant Pathology, College of Agriculture, Karnataka, India
| | - Graeme C. Wright
- Department of Primary Industries, Kingaroy, Queensland, Australia
| | - Kerstin Hell
- International Institute of Tropical Agriculture, Cotonou, Republic of Benin
| | - Ignazio Carbone
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America
- Bioinformatics Research Center, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail:
| |
Collapse
|
42
|
Stewart JE, Thomas KA, Lawrence CB, Dang H, Pryor BM, Timmer LMP, Peever TL. Signatures of recombination in clonal lineages of the citrus brown spot pathogen, Alternaria alternata sensu lato. PHYTOPATHOLOGY 2013; 103:741-749. [PMID: 23441968 DOI: 10.1094/phyto-08-12-0211-r] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Most Alternaria spp. are considered asexual but recent molecular evolution analyses of Alternaria mating-type genes show that the mating locus is under strong purifying selection, indicating a possible role in sexual reproduction. The objective of this study was to determine the mode of reproduction of an Alternaria alternata sensu lato population causing citrus brown spot in central Florida. Mating type of each isolate was determined, and isolates were sequenced at six putatively unlinked loci. Three genetically distinct subpopulations (SH1, SH4A, and SH4B) were identified using network and Bayesian population structure analyses. Results demonstrate that most subpopulations of A. alternata associated with citrus are clonal but some have the ability to extensively recombine through a cryptic sexual cycle or parasexual cycle. Although isolates were sampled in close physical proximity (≈2,500-m² area), we were able to reject a random mating model using multilocus gametic disequilibrium tests for two subpopulations, SH1 and SH4B, suggesting that these subpopulations were predominantly asexual. However, three recombination events were identified in SH1 and SH4B and localized to individuals of opposite mating type, possibly indicating meiotic recombination. In contrast, in the third subpopulation (SH4A), where only one mating type was present, extensive reticulation was evident in network analyses, and multilocus gametic disequilibrium tests were consistent with recombination. Recombination among isolates of the same mating type suggests that a nonmeiotic mechanism of recombination such as the parasexual cycle may be operating in this subpopulation. The level of gene flow detected among subpopulations does not appear to be sufficient to prevent differentiation, and perhaps future speciation, of these A. alternata subpopulations.
Collapse
Affiliation(s)
- Jane E Stewart
- Department of Plant Pathology, Washington State University, Pullman, USA.
| | | | | | | | | | | | | |
Collapse
|
43
|
Horn BW, Olarte RA, Peterson SW, Carbone I. Sexual reproduction in Aspergillus tubingensis from section Nigri. Mycologia 2013; 105:1153-63. [PMID: 23709489 DOI: 10.3852/13-101] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A sclerotium-forming member of Aspergillus section Nigri was sampled from a population in a single field in North Carolina, USA, and identified as A. tubingensis based on genealogical concordance analysis. Aspergillus tubingensis was shown to be heterothallic, with individual strains containing either a MAT1-1 or MAT1-2 mating-type gene. Strains of opposite mating type were crossed on mixed cereal agar and incubated for 5-6 months. Stromata typically formed 1-2 indehiscent ascocarps containing asci and ascospores within the pseudo-parenchymatous matrix in a manner similar to the Petromyces sexual stage from section Flavi, which is closely related to section Nigri. Ascospores of A. tubingensis differed from those of section Flavi species in the reticulate ornamentation of ascospores and the presence of two crests that form an equatorial furrow. Sexual reproduction in A. tubingensis may be useful for enhancing enzyme and organic acid production through recombination-mediated genetic engineering of industrial strains.
Collapse
Affiliation(s)
- Bruce W Horn
- National Peanut Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Dawson, Georgia 39842
| | | | | | | |
Collapse
|
44
|
Krimitzas A, Pyrri I, Kouvelis VN, Kapsanaki-Gotsi E, Typas MA. A phylogenetic analysis of Greek isolates of Aspergillus species based on morphology and nuclear and mitochondrial gene sequences. BIOMED RESEARCH INTERNATIONAL 2013; 2013:260395. [PMID: 23762830 PMCID: PMC3665174 DOI: 10.1155/2013/260395] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 04/09/2013] [Indexed: 12/13/2022]
Abstract
Aspergillus species originating from Greece were examined by morphological and molecular criteria to explore the diversity of this genus. The phylogenetic relationships of these species were determined using sequences from the ITS and IGS region of the nuclear rRNA gene complex, two nuclear genes ( β -tubulin (benA) and RNA polymerase II second largest subunit (rpb2)) and two mitochondrial genes (small rRNA subunit (rns) and cytochrome oxidase subunit I (cox1)) and, where available, related sequences from databases. The morphological characters of the anamorphs and teleomorphs, and the single gene phylogenetic trees, differentiated and placed the species examined in the well-supported sections of Aenei, Aspergillus, Bispori, Candidi, Circumdati, Clavati, Cremei, Flavi, Flavipedes, Fumigati, Nidulantes, Nigri, Restricti, Terrei, Usti, and Zonati, with few uncertainties. The combined use of the three commonly employed nuclear genes (benA, rpb2, and ITS), the IGS region, and two less often used mitochondrial gene sequences (rns and cox1) as a single unit resolved several taxonomic ambiguities. A phylogenetic tree was inferred using Neighbour-Joining, Maximum Parsimony, and Bayesian methods. The strains examined formed seven well-supported clades within the genus Aspergillus. Altogether, the concatenated nuclear and mitochondrial sequences offer additional tools for an improved understanding of phylogenetic relationships within this genus.
Collapse
Affiliation(s)
- Antonios Krimitzas
- Department of Genetics and Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistemiopolis, 15701 Athens, Greece
| | - Ioanna Pyrri
- Department of Ecology and Systematics, Faculty of Biology, National and Kapodistrian University of Athens, Panepistemiopolis, 15784 Athens, Greece
| | - Vassili N. Kouvelis
- Department of Genetics and Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistemiopolis, 15701 Athens, Greece
| | - Evangelia Kapsanaki-Gotsi
- Department of Ecology and Systematics, Faculty of Biology, National and Kapodistrian University of Athens, Panepistemiopolis, 15784 Athens, Greece
| | - Milton A. Typas
- Department of Genetics and Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistemiopolis, 15701 Athens, Greece
| |
Collapse
|
45
|
Krijgsheld P, Bleichrodt R, van Veluw G, Wang F, Müller W, Dijksterhuis J, Wösten H. Development in Aspergillus. Stud Mycol 2013; 74:1-29. [PMID: 23450714 PMCID: PMC3563288 DOI: 10.3114/sim0006] [Citation(s) in RCA: 235] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The genus Aspergillus represents a diverse group of fungi that are among the most abundant fungi in the world. Germination of a spore can lead to a vegetative mycelium that colonizes a substrate. The hyphae within the mycelium are highly heterogeneous with respect to gene expression, growth, and secretion. Aspergilli can reproduce both asexually and sexually. To this end, conidiophores and ascocarps are produced that form conidia and ascospores, respectively. This review describes the molecular mechanisms underlying growth and development of Aspergillus.
Collapse
Affiliation(s)
- P. Krijgsheld
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - R. Bleichrodt
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - G.J. van Veluw
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - F. Wang
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - W.H. Müller
- Biomolecular Imaging, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - J. Dijksterhuis
- Applied and Industrial Mycology, CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - H.A.B. Wösten
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| |
Collapse
|
46
|
Moore GG, Mack BM, Beltz SB. Testing the Efficacy of eGFP-Transformed <i>Aspergillus</i> <i>flavus</i> as Biocontrol Strains. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/fns.2013.44060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
47
|
Arabatzis M, Velegraki A. Sexual reproduction in the opportunistic human pathogen Aspergillus terreus. Mycologia 2012; 105:71-9. [PMID: 23074177 DOI: 10.3852/11-426] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Aspergillus terreus has a worldwide distribution in soil, constitutes the third most important cause of invasive aspergillosis in humans and is classically regarded as a strictly asexual species. Strains of A. terreus were characterized by ITS, β-tubulin and calmodulin sequences. Mating type was identified by amplifying and sequencing MAT1-1 and MAT1-2 genes. One MAT1-2 strain produced hyphal masses when crossed with four MAT1-1 strains on mixed cereal agar after 3 wk at 37 C. Cleistothecia formed inside the hyphal masses and produced asci containing smooth-walled ascospores with an equatorial protuberance. This is the first report of sexual reproduction in A. terreus.
Collapse
Affiliation(s)
- Michael Arabatzis
- Department of Microbiology, National and Kapodistrian University of Athens, Athens, Greece.
| | | |
Collapse
|
48
|
Olarte RA, Horn BW, Dorner JW, Monacell JT, Singh R, Stone EA, Carbone I. Effect of sexual recombination on population diversity in aflatoxin production by Aspergillus flavus and evidence for cryptic heterokaryosis. Mol Ecol 2011; 21:1453-76. [PMID: 22212063 DOI: 10.1111/j.1365-294x.2011.05398.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Aspergillus flavus is the major producer of carcinogenic aflatoxins (AFs) in crops worldwide. Natural populations of A. flavus show tremendous variation in AF production, some of which can be attributed to environmental conditions, differential regulation of the AF biosynthetic pathway and deletions or loss-of-function mutations in the AF gene cluster. Understanding the evolutionary processes that generate genetic diversity in A. flavus may also explain quantitative differences in aflatoxigenicity. Several population studies using multilocus genealogical approaches provide indirect evidence of recombination in the genome and specifically in the AF gene cluster. More recently, A. flavus has been shown to be functionally heterothallic and capable of sexual reproduction in laboratory crosses. In the present study, we characterize the progeny from nine A. flavus crosses using toxin phenotype assays, DNA sequence-based markers and array comparative genome hybridization. We show high AF heritability linked to genetic variation in the AF gene cluster, as well as recombination through the independent assortment of chromosomes and through crossing over within the AF cluster that coincides with inferred recombination blocks and hotspots in natural populations. Moreover, the vertical transmission of cryptic alleles indicates that while an A. flavus deletion strain is predominantly homokaryotic, it may harbour AF cluster genes at a low copy number. Results from experimental matings indicate that sexual recombination is driving genetic and functional hyperdiversity in A. flavus. The results of this study have significant implications for managing AF contamination of crops and for improving biocontrol strategies using nonaflatoxigenic strains of A. flavus.
Collapse
Affiliation(s)
- Rodrigo A Olarte
- Department of Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC 27695, USA
| | | | | | | | | | | | | |
Collapse
|
49
|
A fungal sexual revolution: Aspergillus and Penicillium show the way. Curr Opin Microbiol 2011; 14:649-54. [DOI: 10.1016/j.mib.2011.10.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 09/29/2011] [Accepted: 10/03/2011] [Indexed: 01/09/2023]
|
50
|
Dyer PS, O'Gorman CM. Sexual development and cryptic sexuality in fungi: insights from Aspergillus species. FEMS Microbiol Rev 2011; 36:165-92. [PMID: 22091779 DOI: 10.1111/j.1574-6976.2011.00308.x] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 09/04/2011] [Indexed: 11/30/2022] Open
Abstract
Major insights into sexual development and cryptic sexuality within filamentous fungi have been gained from investigations using Aspergillus species. Here, an overview is first given into sexual morphogenesis in the aspergilli, describing the different types of sexual structures formed and how their production is influenced by a variety of environmental and nutritional factors. It is argued that the formation of cleistothecia and accessory tissues, such as Hülle cells and sclerotia, should be viewed as two independent but co-ordinated developmental pathways. Next, a comprehensive survey of over 75 genes associated with sexual reproduction in the aspergilli is presented, including genes relating to mating and the development of cleistothecia, sclerotia and ascospores. Most of these genes have been identified from studies involving the homothallic Aspergillus nidulans, but an increasing number of studies have now in addition characterized 'sex-related' genes from the heterothallic species Aspergillus fumigatus and Aspergillus flavus. A schematic developmental genetic network is proposed showing the inter-relatedness between these genes. Finally, the discovery of sexual reproduction in certain Aspergillus species that were formerly considered to be strictly asexual is reviewed, and the importance of these findings for cryptic sexuality in the aspergilli as a whole is discussed.
Collapse
Affiliation(s)
- Paul S Dyer
- School of Biology, University of Nottingham, Nottingham, UK.
| | | |
Collapse
|