51
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Wang P, Chang PK, Kong Q, Shan S, Wei Q. Comparison of aflatoxin production of Aspergillus flavus at different temperatures and media: Proteome analysis based on TMT. Int J Food Microbiol 2019; 310:108313. [DOI: 10.1016/j.ijfoodmicro.2019.108313] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 08/13/2019] [Accepted: 08/23/2019] [Indexed: 01/10/2023]
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Zhi QQ, He L, Li JY, Li J, Wang ZL, He GY, He ZM. The Kinetochore Protein Spc105, a Novel Interaction Partner of LaeA, Regulates Development and Secondary Metabolism in Aspergillus flavus. Front Microbiol 2019; 10:1881. [PMID: 31456789 PMCID: PMC6700525 DOI: 10.3389/fmicb.2019.01881] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 07/30/2019] [Indexed: 01/04/2023] Open
Abstract
Nuclear protein LaeA is known as the global regulator of secondary metabolism in Aspergillus. LaeA connects with VeA and VelB to form a heterotrimeric complex, which coordinates fungal development and secondary metabolism. Here, we describe a new interaction partner of LaeA, the kinetochore protein Spc105, from the aflatoxin-producing fungus Aspergillus flavus. We showed that in addition to involvement in nuclear division, Spc105 is required for normal conidiophore development and sclerotia production of A. flavus. Moreover, Spc105 positively regulates the production of secondary metabolites such as aflatoxin and kojic acid, and negatively regulates the production of cyclopiazonic acid. Transcriptome analysis of the Δspc105 strain revealed that 23 backbone genes were differentially expressed, corresponding to 19 of the predicted 56 secondary metabolite gene clusters, suggesting a broad regulatory role of Spc105 in secondary metabolism. Notably, the reduced expression of laeA in our transcriptome data led to the discovery of the correlation between Spc105 and LaeA, and double mutant analysis indicated a functional interdependence between Spc105 and LaeA. Further, in vitro and in vivo protein interaction assays revealed that Spc105 interacts directly with the S-adenosylmethionine (SAM)-binding domain of LaeA, and that the leucine zipper motif in Spc105 is required for this interaction. The Spc105-LaeA interaction identified in our study indicates a cooperative interplay of distinct regulators in A. flavus, providing new insights into fungal secondary metabolism regulation networks.
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Affiliation(s)
- Qing-Qing Zhi
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Lei He
- Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, China
| | - Jie-Ying Li
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jing Li
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zhen-Long Wang
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Guang-Yao He
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zhu-Mei He
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
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Bis-naphthopyrone pigments protect filamentous ascomycetes from a wide range of predators. Nat Commun 2019; 10:3579. [PMID: 31395863 PMCID: PMC6687722 DOI: 10.1038/s41467-019-11377-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 07/05/2019] [Indexed: 12/22/2022] Open
Abstract
It is thought that fungi protect themselves from predation by the production of compounds that are toxic to soil-dwelling animals. Here, we show that a nontoxic pigment, the bis-naphthopyrone aurofusarin, protects Fusarium fungi from a wide range of animal predators. We find that springtails (primitive hexapods), woodlice (crustaceans), and mealworms (insects) prefer feeding on fungi with disrupted aurofusarin synthesis, and mealworms and springtails are repelled by wheat flour amended with the fungal bis-naphthopyrones aurofusarin, viomellein, or xanthomegnin. Predation stimulates aurofusarin synthesis in several Fusarium species and viomellein synthesis in Aspergillus ochraceus. Aurofusarin displays low toxicity in mealworms, springtails, isopods, Drosophila, and insect cells, contradicting the common view that fungal defence metabolites are toxic. Our results indicate that bis-naphthopyrones are defence compounds that protect filamentous ascomycetes from predators through a mechanism that does not involve toxicity.
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54
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Holighaus G, Rohlfs M. Volatile and non-volatile fungal oxylipins in fungus-invertebrate interactions. FUNGAL ECOL 2019. [DOI: 10.1016/j.funeco.2018.09.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Li XM, Li ZY, Wang YD, Wang JQ, Yang PL. Quercetin Inhibits the Proliferation and Aflatoxins Biosynthesis of Aspergillus flavus. Toxins (Basel) 2019; 11:toxins11030154. [PMID: 30857280 PMCID: PMC6468572 DOI: 10.3390/toxins11030154] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 03/03/2019] [Accepted: 03/05/2019] [Indexed: 01/10/2023] Open
Abstract
In this work of quercetin’s anti-proliferation action on A. flavus, we revealed that quercetin can effectively hamper the proliferation of A. flavus in dose-effect and time-effect relationships. We tested whether quercetin induced apoptosis in A. flavus via various detection methods, such as phosphatidylserine externalization and Hoechst 33342 staining. The results showed that quercetin had no effect on phosphatidylserine externalization and cell nucleus in A. flavus. Simultaneously, quercetin reduced the levels of reactive oxygen species (ROS). For a better understanding of the molecular mechanism of the A. flavus response to quercetin, the RNA-Seq was used to explore the transcriptomic profiles of A. flavus. According to transcriptome sequencing data, quercetin inhibits the proliferation and aflatoxin biosynthesis by regulating the expression of development-related genes and aflatoxin production-related genes. These results will provide some theoretical basis for quercetin as an anti-mildew agent resource.
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Affiliation(s)
- Xiu-Mei Li
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
- National Engineering Research Center of Biological Feed, Beijing 100081, China.
| | - Zhong-Yuan Li
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of Ministry of Education & Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Ya-Dong Wang
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of Ministry of Education & Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Jin-Quan Wang
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| | - Pei-Long Yang
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
- National Engineering Research Center of Biological Feed, Beijing 100081, China.
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56
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Abstract
One of the exciting movements in microbial sciences has been a refocusing and revitalization of efforts to mine the fungal secondary metabolome. The magnitude of biosynthetic gene clusters (BGCs) in a single filamentous fungal genome combined with the historic number of sequenced genomes suggests that the secondary metabolite wealth of filamentous fungi is largely untapped. Mining algorithms and scalable expression platforms have greatly expanded access to the chemical repertoire of fungal-derived secondary metabolites. In this Review, I discuss new insights into the transcriptional and epigenetic regulation of BGCs and the ecological roles of fungal secondary metabolites in warfare, defence and development. I also explore avenues for the identification of new fungal metabolites and the challenges in harvesting fungal-derived secondary metabolites.
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Singh D, Lee S, Lee CH. Fathoming Aspergillus oryzae metabolomes in formulated growth matrices. Crit Rev Biotechnol 2019; 39:35-49. [PMID: 30037282 DOI: 10.1080/07388551.2018.1490246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 05/17/2018] [Accepted: 05/27/2018] [Indexed: 01/11/2023]
Abstract
The stochasticity of Aspergillus oryzae (Trivially: the koji mold) pan-metabolomes commensurate with its ubiquitously distributed landscapes, i.e. growth matrices have been seemed uncharted since its food fermentative systems are mostly being investigated. In this review, we explicitly have discussed the likely tendencies of A. oryzae metabolomes pertaining to its growth milieu formulated with substrate matrices of varying nature, composition, texture, and associated physicochemical parameters. We envisaged typical food matrices, namely, meju, koji, and moromi as the semi-natural cultivation models toward delineating the metabolomic patterns of the koji mold, which synergistically influences the organoleptic and functional properties of the end products. Further, we highlighted how tailored conditions in sub-natural growth matrices, i.e. synthetic cultivation media blends, inducers, and growth surfaces, may influence A. oryzae metabolomes and targeted phenotypes. In general, the sequential or synchronous growth of A. oryzae on formulated matrices results in a number of metabolic tradeoffs with its immediate microenvironment influencing its adaptive and regulatory metabolomes. In broader context, evaluating the metabolic plasticity of A. oryzae relative to the tractable variables in formulated growth matrices might help approximate its growth and metabolism in the more complex natural matrices and environs. These approaches may considerably help in the design and manipulation of hybrid cultivation systems towards the efficient harnessing of commercial molds.
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Affiliation(s)
- Digar Singh
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Korea
| | - Sunmin Lee
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Korea
| | - Choong Hwan Lee
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Korea
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58
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Fung SY, Cheong PCH, Tan NH, Ng ST, Tan CS. Nutritional evaluation on Lignosus cameronensis C. S. Tan, a medicinal Polyporaceae. IUBMB Life 2019; 71:821-826. [PMID: 30629799 DOI: 10.1002/iub.2006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 12/03/2018] [Accepted: 12/17/2018] [Indexed: 12/21/2022]
Abstract
Sclerotial powder of a cultivated species of the Tiger Milk Mushroom, Lignosus cameronensis was analysed for its nutritional components and compared against species of the same genus, Lignosus rhinocerus and Lignosus tigris. All three species have been used by indigenous tribes in Peninsular Malaysia as medicinal mushrooms. Content of carbohydrate, fibre, mineral, amino acid, palatable index, fat, ash and moisture were determined. L. cameronensis sclerotial material consists of carbohydrate (79.7%), protein (12.4%) and dietary fibre (5.4%) with low fat (1.7%) and no free sugar. It has the highest content of total carbohydrate (791 g kg-1 ), energy value (3,700 kcal kg-1 ) and calcium (0.85 g kg-1 ). The crude protein content (123 g kg-1 ) is comparable to that of L. rhinocerus with its main amino acids consisting of glutamic acid, aspartic acid and leucine. The umami index is determined to be 0.27. The total essential amino acid (45 g kg-1 ) is comparable to that of L. tigris. The main mineral is potassium (1.51 g kg-1 ) and the Na/K ratio was <0.6. Heavy metals such as mercury, cadmium, lead and arsenic were absent. L. cameronensis has the highest amount of food energy, total carbohydrate and calcium compared to those of both L. rhinocerus and L. tigris. The essential amino acids comprised almost 40% of the total amino acid content, slightly more than that reported from sclerotial powder of the L. tigris. © 2019 IUBMB Life, 9999(9999):1-6, 2019.
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Affiliation(s)
- Shin Yee Fung
- Medicinal Mushroom Research Group, Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Peter Chiew Hing Cheong
- Medicinal Mushroom Research Group, Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Nget Hong Tan
- Medicinal Mushroom Research Group, Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Szu Ting Ng
- Ligno Biotech Sdn. Bhd., Seri Kembangan, Selangor, Malaysia
| | - Chon Seng Tan
- Ligno Biotech Sdn. Bhd., Seri Kembangan, Selangor, Malaysia
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59
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Cary JW, Entwistle S, Satterlee T, Mack BM, Gilbert MK, Chang PK, Scharfenstein L, Yin Y, Calvo AM. The Transcriptional Regulator Hbx1 Affects the Expression of Thousands of Genes in the Aflatoxin-Producing Fungus Aspergillus flavus. G3 (BETHESDA, MD.) 2019; 9:167-178. [PMID: 30425054 PMCID: PMC6325891 DOI: 10.1534/g3.118.200870] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/09/2018] [Indexed: 12/21/2022]
Abstract
In filamentous fungi, homeobox proteins are conserved transcriptional regulators described to control conidiogenesis and fruiting body formation. Eight homeobox (hbx) genes are found in the genome of the aflatoxin-producing ascomycete, Aspergillus flavus While loss-of-function of seven of the eight genes had little to no effect on fungal growth and development, disruption of hbx1, resulted in aconidial colonies and lack of sclerotial production. Furthermore, the hbx1 mutant was unable to produce aflatoxins B1 and B2, cyclopiazonic acid and aflatrem. In the present study, hbx1 transcriptome analysis revealed that hbx1 has a broad effect on A. flavus gene expression, and the effect of hbx1 increases overtime, impacting more than five thousand protein-coding genes. Among the affected genes, those in the category of secondary metabolism (SM), followed by that of cellular transport, were the most affected. Specifically, regarding the effect of hbx1 on SM, we found that genes in 44 SM gene clusters where upregulated while 49 were downregulated in the absence of hbx1, including genes in the SM clusters responsible for the synthesis of asparasone, piperazine and aflavarin, all known to be associated with sclerotia. In addition, our study revealed that hbx1 affects the expression of other transcription factor genes involved in development, including the conidiation central regulatory pathway and flb genes.
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Affiliation(s)
- Jeffrey W Cary
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Sarah Entwistle
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois
| | - Timothy Satterlee
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois
| | - Brian M Mack
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Matthew K Gilbert
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Perng K Chang
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Leslie Scharfenstein
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Yanbin Yin
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois
| | - Ana M Calvo
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois
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60
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Trichoderma atroviride from Predator to Prey: Role of the Mitogen-Activated Protein Kinase Tmk3 in Fungal Chemical Defense against Fungivory by Drosophila melanogaster Larvae. Appl Environ Microbiol 2019; 85:AEM.01825-18. [PMID: 30389761 PMCID: PMC6328759 DOI: 10.1128/aem.01825-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/22/2018] [Indexed: 12/28/2022] Open
Abstract
Fungi, like other organisms, have natural predators, including fungivorous nematodes and arthropods that use them as an important food source. Thus, they require mechanisms to detect and respond to injury. Trichoderma atroviride responds to mycelial injury by rapidly regenerating its hyphae and developing asexual reproduction structures. Whether this injury response is associated with attack by fungivorous insects is unknown. Therefore, determining the possible conservation of a defense mechanism to predation in T. atroviride and plants and elucidating the mechanisms involved in the establishment of this response is of major interest. Here, we describe the chemical response of T. atroviride to mechanical injury and fungivory and the role of a MAPK pathway in the regulation of this response. The response to injury represents an important strategy for animals and plants to survive mechanical damage and predation. Plants respond to injury by activating a defense response that includes the production of an important variety of compounds that help them withstand predator attack and recover from mechanical injury (MI). Similarly, the filamentous fungus Trichoderma atroviride responds to MI by strongly modifying its transcriptional profile and producing asexual reproduction structures (conidia). Here, we analyzed whether the response to MI in T. atroviride is related to a possible predator defense mechanism from a metabolic perspective. We found that the production of specific groups of secondary metabolites increases in response to MI but is reduced after fungivory by Drosophila melanogaster larvae. We further show that fungivory results in repression of the expression of genes putatively involved in the regulation of secondary metabolite production in T. atroviride. Activation of secondary metabolite production appears to depend on the mitogen-activated protein kinase (MAPK) Tmk3. Interestingly, D. melanogaster larvae preferred to feed on a tmk3 gene replacement mutant rather than on the wild-type strain. Consumption of the mutant strain, however, resulted in increased larval mortality. IMPORTANCE Fungi, like other organisms, have natural predators, including fungivorous nematodes and arthropods that use them as an important food source. Thus, they require mechanisms to detect and respond to injury. Trichoderma atroviride responds to mycelial injury by rapidly regenerating its hyphae and developing asexual reproduction structures. Whether this injury response is associated with attack by fungivorous insects is unknown. Therefore, determining the possible conservation of a defense mechanism to predation in T. atroviride and plants and elucidating the mechanisms involved in the establishment of this response is of major interest. Here, we describe the chemical response of T. atroviride to mechanical injury and fungivory and the role of a MAPK pathway in the regulation of this response.
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61
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Kovač T, Šarkanj B, Crevar B, Kovač M, Lončarić A, Strelec I, Ezekiel CN, Sulyok M, Krska R. Aspergillus flavus NRRL 3251 Growth, Oxidative Status, and Aflatoxins Production Ability In Vitro under Different Illumination Regimes. Toxins (Basel) 2018; 10:E528. [PMID: 30544693 PMCID: PMC6316533 DOI: 10.3390/toxins10120528] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 12/05/2018] [Accepted: 12/06/2018] [Indexed: 12/29/2022] Open
Abstract
Aspergillus flavus is the most important mycotoxin-producing fungus involved in the global episodes of aflatoxin B₁ contamination of crops at both the pre-harvest and post-harvest stages. However, in order to effectively control aflatoxin contamination in crops using antiaflatoxigenic and/or antifungal compounds, some of which are photosensitive, a proper understanding of the photo-sensitive physiology of potential experimental strains need to be documented. The purpose of the study is therefore to evaluate the effect of visible (VIS) light illumination on growth and conidiation, aflatoxin production ability and modulation of A. flavus oxidative status during in vitro experiment. Aflatoxigenic A. flavus strain was inoculated in aflatoxin-inducing YES media and incubated under three different VIS illumination regimes during a 168 h growth period at 29 °C. VIS illumination reduced A. flavus mycelia biomass yield, both during growth on plates and in liquid media, promoted conidiation and increased the aflatoxin production. Furthermore, aflatoxin production increased with increased reactive oxidative species (ROS) levels at 96 h of growth, confirming illumination-driven oxidative stress modulation activity on A. flavus cells.
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Affiliation(s)
- Tihomir Kovač
- Department of Applied Chemistry and Ecology, Faculty of Food Technology, Josip Juraj Strossmayer University of Osijek, Franje Kuhača 20, Osijek 31000, Croatia.
- Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences Vienna (BOKU), Konrad Lorenzstr. 20, Tulln 3430, Austria.
| | - Bojan Šarkanj
- Department of Applied Chemistry and Ecology, Faculty of Food Technology, Josip Juraj Strossmayer University of Osijek, Franje Kuhača 20, Osijek 31000, Croatia.
- Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences Vienna (BOKU), Konrad Lorenzstr. 20, Tulln 3430, Austria.
- Department of Food technology, University North, Trg dr. Žarka Dolinara 1, Koprivnica 48000, Croatia.
| | - Biljana Crevar
- Department of Applied Chemistry and Ecology, Faculty of Food Technology, Josip Juraj Strossmayer University of Osijek, Franje Kuhača 20, Osijek 31000, Croatia.
| | - Marija Kovač
- Inspecto Ltd., Industrijska zona Nemetin, Vukovarska cesta 239b, Osijek 31000, Croatia.
| | - Ante Lončarić
- Department of Applied Chemistry and Ecology, Faculty of Food Technology, Josip Juraj Strossmayer University of Osijek, Franje Kuhača 20, Osijek 31000, Croatia.
| | - Ivica Strelec
- Department of Applied Chemistry and Ecology, Faculty of Food Technology, Josip Juraj Strossmayer University of Osijek, Franje Kuhača 20, Osijek 31000, Croatia.
| | - Chibundu N Ezekiel
- Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences Vienna (BOKU), Konrad Lorenzstr. 20, Tulln 3430, Austria.
- Department of Microbiology, Babcock University, Ilishan Remo 121103, Ogun State, Nigeria.
| | - Michael Sulyok
- Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences Vienna (BOKU), Konrad Lorenzstr. 20, Tulln 3430, Austria.
| | - Rudolf Krska
- Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences Vienna (BOKU), Konrad Lorenzstr. 20, Tulln 3430, Austria.
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, University Road, Belfast BT7 1NN, Northern Ireland, UK.
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62
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Characterization of the velvet regulators in Aspergillus flavus. J Microbiol 2018; 56:893-901. [PMID: 30361976 DOI: 10.1007/s12275-018-8417-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 08/22/2018] [Accepted: 08/28/2018] [Indexed: 12/14/2022]
Abstract
Fungal development and secondary metabolism are closely associated via the activities of the fungal NK-kB-type velvet regulators that are highly conserved in filamentous fungi. Here, we investigated the roles of the velvet genes in the aflatoxigenic fungus Aspergillus flavus. Distinct from other Aspergillus species, the A. flavus genome contains five velvet genes, veA, velB, velC, velD, and vosA. The deletion of velD blocks the production of aflatoxin B1, but does not affect the formation of sclerotia. Expression analyses revealed that vosA and velB mRNAs accumulated at high levels during the late phase of asexual development and in conidia. The absence of vosA or velB decreased the content of conidial trehalose and the tolerance of conidia to the thermal and UV stresses. In addition, double mutant analyses demonstrated that VosA and VelB play an inter-dependent role in trehalose biosynthesis and conidial stress tolerance. Together with the findings of previous studies, the results of the present study suggest that the velvet regulators play the conserved and vital role in sporogenesis, conidial trehalose biogenesis, stress tolerance, and aflatoxin biosynthesis in A. flavus.
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63
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Liang JH, Huo XK, Cheng ZB, Sun CP, Zhao JC, Kang XH, Zhang TY, Chen ZJ, Yang TM, Wu YY, Deng XP, Zhang YX. An indole diterpenoid isolated from the fungus Drechmeria sp. and its antimicrobial activity. Nat Prod Res 2018; 33:2770-2776. [DOI: 10.1080/14786419.2018.1501050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Jia-Hao Liang
- College of Pharmacy, College (Institute) of Integrative Medicine, The National & Local Joint Engineering Research Center for Drug Development of Neurodegenerative Disease, Dalian Medical University, Dalian, China
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Xiao-Kui Huo
- College of Pharmacy, College (Institute) of Integrative Medicine, The National & Local Joint Engineering Research Center for Drug Development of Neurodegenerative Disease, Dalian Medical University, Dalian, China
| | | | - Cheng-Peng Sun
- College of Pharmacy, College (Institute) of Integrative Medicine, The National & Local Joint Engineering Research Center for Drug Development of Neurodegenerative Disease, Dalian Medical University, Dalian, China
| | - Jian-Chao Zhao
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Xiao-Hui Kang
- College of Pharmacy, College (Institute) of Integrative Medicine, The National & Local Joint Engineering Research Center for Drug Development of Neurodegenerative Disease, Dalian Medical University, Dalian, China
| | - Tian-Yuan Zhang
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Zhong-Jian Chen
- Wenshan Sanqi Research Institute, Wenshan University, Wenshan, China
| | - Tian-Mei Yang
- Institute of Medicinal Plants, Yunnan Academy of Agricultural Sciences, Kunming, China
| | - Ying-Ying Wu
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Xiao-Peng Deng
- Dalian Maternal and Child Care Health Hospital, Dalian, China
| | - Yi-Xuan Zhang
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
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64
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Yao G, Yue Y, Fu Y, Fang Z, Xu Z, Ma G, Wang S. Exploration of the Regulatory Mechanism of Secondary Metabolism by Comparative Transcriptomics in Aspergillus flavus. Front Microbiol 2018; 9:1568. [PMID: 30131770 PMCID: PMC6090018 DOI: 10.3389/fmicb.2018.01568] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 06/25/2018] [Indexed: 12/31/2022] Open
Abstract
Mycotoxins cause a huge threaten to agriculture, food safety, and human and animal life. Among them, aflatoxins (AFs) have always been considered the most potent carcinogens, and filamentous fungi from Aspergillus genus are their major producers, especially A. flavus. Although the biosynthesis path of these chemicals had been well-identified, the regulatory mechanisms controlling expression of AF gene cluster were poorly understood. In this report, genome-wide transcriptome profiles of A. flavus from AF conducing [yeast sucrose media (YES)] and non-conducing [yeast peptone media (YEP)] conditions were compared by using deep RNA sequencing (RNA-seq), and the results revealed that AF biosynthesis pathway and biosynthesis of amino acids were significantly upregulated in YES vs. YEP. Further, a novel LaeA-like methyltransferase AFLA_121330 (Lael1) was identified for the first time, to play a specific role in the regulation of AF biosynthesis. Contrary to LaeA, which gene deletion reduced the level, lael1 deletion resulted in a significant increase in AF production. Further, co-expression network analysis revealed that mitochondrial pyruvate transport and signal peptide processing were potentially involved in AF synthesis for the first time, as well as biological processes of ribosome, branched-chain amino acid biosynthetic process and translation were co-regulated by AfRafA and AfStuA. To sum up, our analyses could provide novel insights into the molecular mechanism for controlling the AF and other secondary metabolite synthesis, adding novel targets for plant breeding and making fungicides.
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Affiliation(s)
- Guangshan Yao
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yuewei Yue
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yishi Fu
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhou Fang
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhangling Xu
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Genli Ma
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shihua Wang
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
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65
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Izquierdo-Bueno I, González-Rodríguez VE, Simon A, Dalmais B, Pradier JM, Le Pêcheur P, Mercier A, Walker AS, Garrido C, Collado IG, Viaud M. Biosynthesis of abscisic acid in fungi: identification of a sesquiterpene cyclase as the key enzyme in Botrytis cinerea. Environ Microbiol 2018; 20:2469-2482. [PMID: 29708647 DOI: 10.1111/1462-2920.14258] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 12/25/2022]
Abstract
While abscisic acid (ABA) is known as a hormone produced by plants through the carotenoid pathway, a small number of phytopathogenic fungi are also able to produce this sesquiterpene but they use a distinct pathway that starts with the cyclization of farnesyl diphosphate (FPP) into 2Z,4E-α-ionylideneethane which is then subjected to several oxidation steps. To identify the sesquiterpene cyclase (STC) responsible for the biosynthesis of ABA in fungi, we conducted a genomic approach in Botrytis cinerea. The genome of the ABA-overproducing strain ATCC58025 was fully sequenced and five STC-coding genes were identified. Among them, Bcstc5 exhibits an expression profile concomitant with ABA production. Gene inactivation, complementation and chemical analysis demonstrated that BcStc5/BcAba5 is the key enzyme responsible for the key step of ABA biosynthesis in fungi. Unlike what is observed for most of the fungal secondary metabolism genes, the key enzyme-coding gene Bcstc5/Bcaba5 is not clustered with the other biosynthetic genes, i.e., Bcaba1 to Bcaba4 that are responsible for the oxidative transformation of 2Z,4E-α-ionylideneethane. Finally, our study revealed that the presence of the Bcaba genes among Botrytis species is rare and that the majority of them do not possess the ability to produce ABA.
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Affiliation(s)
- Inmaculada Izquierdo-Bueno
- Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Cádiz, Cádiz, 11510 Puerto Real, Spain
| | - Victoria E González-Rodríguez
- Departamento de Biomedicina, Biotecnología y Salud Pública, Laboratorio de Microbiología, Facultad de Ciencias de Mar y Ambientales, Universidad de Cádiz, Puerto Real, Cádiz 11510, Spain
| | - Adeline Simon
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France
| | - Bérengère Dalmais
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France
| | - Jean-Marc Pradier
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France
| | - Pascal Le Pêcheur
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France
| | - Alex Mercier
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France.,Université Paris-Sud, 91405 Orsay, France
| | - Anne-Sophie Walker
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France
| | - Carlos Garrido
- Departamento de Biomedicina, Biotecnología y Salud Pública, Laboratorio de Microbiología, Facultad de Ciencias de Mar y Ambientales, Universidad de Cádiz, Puerto Real, Cádiz 11510, Spain
| | - Isidro González Collado
- Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Cádiz, Cádiz, 11510 Puerto Real, Spain
| | - Muriel Viaud
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France
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66
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Demissie ZA, Foote SJ, Tan Y, Loewen MC. Profiling of the Transcriptomic Responses of Clonostachys rosea Upon Treatment With Fusarium graminearum Secretome. Front Microbiol 2018; 9:1061. [PMID: 29930539 PMCID: PMC5999785 DOI: 10.3389/fmicb.2018.01061] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 05/04/2018] [Indexed: 11/23/2022] Open
Abstract
Clonostachys rosea strain ACM941 is a fungal bio-control agent patented against the causative agent of Fusarium Head Blight, Fusarium graminearum. Although the molecular details remain enigmatic, previous studies have suggested that C. rosea may secrete F. graminearum growth inhibitors. Further toward this, experiments described herein show that induction of C. rosea cultures by the addition of an aliquot of F. graminearum(Fg)-spent media (including macroconidia), yield C. rosea (Cr)-spent media that elicited higher anti-F. graminearum activity than either control or deoxynivalenol (DON)-induced Cr-spent media. To gain additional insight into the genetic and metabolic factors modulating this interaction, transcriptomic (RNAseq) profiles of C. rosea in response to DON and Fg-spent media treatment, were developed. This analysis revealed 24,112 C. rosea unigenes, of which 5,605 and 6,285 were differentially regulated by DON and F-spent media, respectively. More than half of these unigenes were up-regulated, with annotations, most notably in the Fg-spent media treatment data, suggesting enhancement of polyketide (PK) and non-ribosomal peptide (NRP) secondary metabolite precursor synthesis, and PK/NRP-like synthases. Four ABC transporters were also up-regulated in response to Fg-spent media. Further analysis showed that the PK and NRP-like synthases belong to three gene clusters that also include ABC transporters, and other genes known to tailor secondary metabolite biosynthesis. The RNAseq data was further validated using quantitative RT-qPCR. Taken together, these results show that C. rosea responds to the presence of Fg-spent media (and to a lesser extent, DON-alone) by up-regulating unique aspects of its secondary metabolism-related genetic repertoire. The identities and roles of C. rosea secondary metabolites produced by the targeted gene clusters are now under investigation.
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Affiliation(s)
- Zerihun A. Demissie
- Aquatic and Crop Resource Development, National Research Council Canada, Ottawa, ON, Canada
| | - Simon J. Foote
- Human Health Therapeutics, National Research Council of Canada, Ottawa, ON, Canada
| | - Yifang Tan
- Aquatic and Crop Resource Development, National Research Council Canada, Saskatoon, SK, Canada
| | - Michele C. Loewen
- Aquatic and Crop Resource Development, National Research Council Canada, Ottawa, ON, Canada
- Department of Biomedical and Molecular Sciences, Queens University, Kingston, ON, Canada
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67
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Rahnama M, Johnson RD, Voisey CR, Simpson WR, Fleetwood DJ. The Global Regulatory Protein VelA Is Required for Symbiosis Between the Endophytic Fungus Epichloë festucae and Lolium perenne. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:591-604. [PMID: 29315021 DOI: 10.1094/mpmi-11-17-0286-r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Epichloë species fungi form bioprotective endophytic symbioses with many cool-season grasses, including agriculturally important forage grasses. Despite its importance, relatively little is known about the molecular details of the interaction and the regulatory genes involved. The conserved velvet-domain protein VelA (or VeA) is a global regulator of a number of cellular and developmental functions in fungi. In this study, the E. festucae velA gene was functionally characterized in vitro and during interaction with perennial ryegrass. The velA gene is required in E. festucae for resistance to osmotic and cell wall-damaging stresses, repression of conidiation, and normal hyphal morphology during nutrient-limited in-vitro conditions. Expression of velA in E. festucae is light- and nitrogen-dependent and is tissue-specific in mature infected plants. In-planta studies showed that velA is required in E. festucae for a compatible interaction. Inoculating seedlings with mutant ΔvelA induced callose deposition and H2O2 production, and a high level of seedling death was observed. In surviving plants infected with ΔvelA mutant fungi, plants were stunted and we observed increased biomass and invasion of vascular bundles. Overall, this work characterizes a key fungal regulatory factor in this increasingly important model symbiotic association.
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Affiliation(s)
- M Rahnama
- 1 AgResearch, Grasslands Research Centre, Palmerston North, New Zealand; and
- 2 School of Biological Sciences, University of Auckland, New Zealand
| | - R D Johnson
- 1 AgResearch, Grasslands Research Centre, Palmerston North, New Zealand; and
| | - C R Voisey
- 1 AgResearch, Grasslands Research Centre, Palmerston North, New Zealand; and
| | - W R Simpson
- 1 AgResearch, Grasslands Research Centre, Palmerston North, New Zealand; and
| | - D J Fleetwood
- 1 AgResearch, Grasslands Research Centre, Palmerston North, New Zealand; and
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68
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Dattenböck C, Tisch D, Schuster A, Monroy AA, Hinterdobler W, Schmoll M. Gene regulation associated with sexual development and female fertility in different isolates of Trichoderma reesei. Fungal Biol Biotechnol 2018; 5:9. [PMID: 29785273 PMCID: PMC5952832 DOI: 10.1186/s40694-018-0055-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 04/12/2018] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Trichoderma reesei is one of the most frequently used filamentous fungi in industry for production of homologous and heterologous proteins. The ability to use sexual crossing in this fungus was discovered several years ago and opens up new perspectives for industrial strain improvement and investigation of gene regulation. RESULTS Here we investigated the female sterile strain QM6a in comparison to the fertile isolate CBS999.97 and backcrossed derivatives of QM6a, which have regained fertility (FF1 and FF2 strains) in both mating types under conditions of sexual development. We found considerable differences in gene regulation between strains with the CBS999.97 genetic background and the QM6a background. Regulation patterns of QM6a largely clustered with the backcrossed FF1 and FF2 strains. Differential regulation between QM6a and FF1/FF2 as well as clustering of QM6a patterns with those of CBS999.97 strains was also observed. Consistent mating type dependent regulation was limited to mating type genes and those involved in pheromone response, but included also nta1 encoding a putative N-terminal amidase previously not associated with development. Comparison of female sterile QM6a with female fertile strains showed differential expression in genes encoding several transcription factors, metabolic genes and genes involved in secondary metabolism. CONCLUSIONS Evaluation of the functions of genes specifically regulated under conditions of sexual development and of genes with highest levels of transcripts under these conditions indicated a relevance of secondary metabolism for sexual development in T. reesei. Among others, the biosynthetic genes of the recently characterized SOR cluster are in this gene group. However, these genes are not essential for sexual development, but rather have a function in protection and defence against competitors during reproduction.
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Affiliation(s)
- Christoph Dattenböck
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Konrad Lorenz Straße 24, 3430 Tulln, Austria
| | - Doris Tisch
- Institute of Chemical Engineering, Research Area Molecular Biotechnology, TU Wien, 1060 Vienna, Austria
| | - Andre Schuster
- Institute of Chemical Engineering, Research Area Molecular Biotechnology, TU Wien, 1060 Vienna, Austria
| | - Alberto Alonso Monroy
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Konrad Lorenz Straße 24, 3430 Tulln, Austria
| | - Wolfgang Hinterdobler
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Konrad Lorenz Straße 24, 3430 Tulln, Austria
| | - Monika Schmoll
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Konrad Lorenz Straße 24, 3430 Tulln, Austria
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69
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Drechmerin H, a novel 1(2), 2(18)-diseco indole diterpenoid from the fungus Drechmeria sp. as a natural agonist of human pregnane X receptor. Bioorg Chem 2018; 79:250-256. [PMID: 29775950 DOI: 10.1016/j.bioorg.2018.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 04/21/2018] [Accepted: 05/02/2018] [Indexed: 11/20/2022]
Abstract
A novel 1(2), 2(18)-diseco indole diterpenoid, drechmerin H (1), was isolated from the fermentation broth of Drechmeria sp. together with a new indole diterpenoid, 2'-epi terpendole A (3), and a known analogue, terpendole A (2). Their structures were determined by HRESIMS, 1D and 2D NMR, ECD, and X-ray single crystal diffraction analyses as well as quantum chemical calculation. The abosulte configuration of terpendole A (2) was determined for the first time. Compound 1 displayed the significant agonistic effect on pregnane X receptor (PXR) with EC50 value of 134.91 ± 2.01 nM, and its interaction with PXR was investigated by molecular docking. Meantime, a plausible biosynthetic pathway for compounds 1-3 is also discussed in the present work.
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70
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The developmental regulator Pcz1 affects the production of secondary metabolites in the filamentous fungus Penicillium roqueforti. Microbiol Res 2018; 212-213:67-74. [PMID: 29853169 DOI: 10.1016/j.micres.2018.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 03/16/2018] [Accepted: 05/03/2018] [Indexed: 12/27/2022]
Abstract
Penicillium roqueforti is used in the production of several kinds of ripened blue-veined cheeses. In addition, this fungus produces interesting secondary metabolites such as roquefortine C, andrastin A and mycophenolic acid. To date, there is scarce information concerning the regulation of the production of these secondary metabolites. Recently, the gene named pcz1 (Penicillium C6 zinc domain protein 1) was described in P. roqueforti, which encodes for a Zn(II)2Cys6 protein that controls growth and developmental processes in this fungus. However, its effect on secondary metabolism is currently unknown. In this work, we have analyzed how the overexpression and down-regulation of pcz1 affect the production of roquefortine C, andrastin A and mycophenolic acid in P. roqueforti. The three metabolites were drastically reduced in the pcz1 down-regulated strains. However, when pcz1 was overexpressed, only mycophenolic acid was overproduced while, on the contrary, levels of roquefortine C and andrastin A were diminished. Importantly, these results match the expression pattern of key genes involved in the biosynthesis of these metabolites. Taken together, our results suggest that Pcz1 plays a key role in regulating secondary metabolism in the fungus Penicillium roqueforti.
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71
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Singh D, Lee CH. Volatiles Mediated Interactions Between Aspergillus oryzae Strains Modulate Morphological Transition and Exometabolomes. Front Microbiol 2018; 9:628. [PMID: 29670599 PMCID: PMC5893800 DOI: 10.3389/fmicb.2018.00628] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 03/19/2018] [Indexed: 11/13/2022] Open
Abstract
Notwithstanding its mitosporic nature, an improbable morpho-transformation state i. e., sclerotial development (SD), is vaguely known in Aspergillus oryzae. Nevertheless an intriguing phenomenon governing mold's development and stress response, the effects of exogenous factors engendering SD, especially the volatile organic compounds (VOCs) mediated interactions (VMI) pervasive in microbial niches have largely remained unexplored. Herein, we examined the effects of intra-species VMI on SD in A. oryzae RIB 40, followed by comprehensive analyses of associated growth rates, pH alterations, biochemical phenotypes, and exometabolomes. We cultivated A. oryzae RIB 40 (S1VMI: KACC 44967) opposite a non-SD partner strain, A. oryzae (S2: KCCM 60345), conditioning VMI in a specially designed “twin plate assembly.” Notably, SD in S1VMI was delayed relative to its non-conditioned control (S1) cultivated without partner strain (S2) in twin plate. Selectively evaluating A. oryzae RIB 40 (S1VMI vs. S1) for altered phenotypes concomitant to SD, we observed a marked disparity for corresponding growth rates (S1VMI < S1)7days, media pH (S1VMI > S1)7days, and biochemical characteristics viz., protease (S1VMI > S1)7days, amylase (S1VMI > nS1)3–7days, and antioxidants (S1VMI > S1)7days levels. The partial least squares—discriminant analysis (PLS-DA) of gas chromatography—time of flight—mass spectrometry (GC-TOF-MS) datasets for primary metabolites exhibited a clustered pattern (PLS1, 22.04%; PLS2, 11.36%), with 7 days incubated S1VMI extracts showed higher abundance of amino acids, sugars, and sugar alcohols with lower organic acids and fatty acids levels, relative to S1. Intriguingly, the higher amino acid and sugar alcohol levels were positively correlated with antioxidant activity, likely impeding SD in S1VMI. Further, the PLS-DA (PLS1, 18.11%; PLS2, 15.02%) based on liquid chromatography—mass spectrometry (LC-MS) datasets exhibited a notable disparity for post-SD (9–11 days) sample extracts with higher oxylipins and 13-desoxypaxilline levels in S1VMI relative to S1, intertwining Aspergillus morphogenesis and secondary metabolism. The analysis of VOCs for the 7 days incubated samples displayed considerably higher accumulation of C-8 compounds in the headspace of twin-plate experimental sets (S1VMI:S2) compared to those in non-conditioned controls (S1 and S2—without respective partner strains), potentially triggering altered morpho-transformation and concurring biochemical as well as metabolic states in molds.
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Affiliation(s)
- Digar Singh
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, South Korea
| | - Choong H Lee
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, South Korea
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72
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Caballero Ortiz S, Trienens M, Pfohl K, Karlovsky P, Holighaus G, Rohlfs M. Phenotypic responses to microbial volatiles render a mold fungus more susceptible to insect damage. Ecol Evol 2018; 8:4328-4339. [PMID: 29721301 PMCID: PMC5916272 DOI: 10.1002/ece3.3978] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/05/2018] [Accepted: 02/09/2018] [Indexed: 01/07/2023] Open
Abstract
In decomposer systems, fungi show diverse phenotypic responses to volatile organic compounds of microbial origin (volatiles). The mechanisms underlying such responses and their consequences for the performance and ecological success of fungi in a multitrophic community context have rarely been tested explicitly. We used a laboratory‐based approach in which we investigated a tripartite yeast–mold–insect model decomposer system to understand the possible influence of yeast‐borne volatiles on the ability of a chemically defended mold fungus to resist insect damage. The volatile‐exposed mold phenotype (1) did not exhibit protein kinase A‐dependent morphological differentiation, (2) was more susceptible to insect foraging activity, and (3) had reduced insecticidal properties. Additionally, the volatile‐exposed phenotype was strongly impaired in secondary metabolite formation and unable to activate “chemical defense” genes upon insect damage. These results suggest that volatiles can be ecologically important factors that affect the chemical‐based combative abilities of fungi against insect antagonists and, consequently, the structure and dynamics of decomposer communities.
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Affiliation(s)
- Silvia Caballero Ortiz
- J.F. Blumenbach Institute of Zoology and Anthropology Animal Ecology Group University of Goettingen Goettingen Germany
| | - Monika Trienens
- J.F. Blumenbach Institute of Zoology and Anthropology Animal Ecology Group University of Goettingen Goettingen Germany.,Present address: Institute for Evolution and Biodiversity University of Muenster Muenster Germany
| | - Katharina Pfohl
- Molecular Phytopathology and Mycotoxin Research University of Goettingen Goettingen Germany
| | - Petr Karlovsky
- Molecular Phytopathology and Mycotoxin Research University of Goettingen Goettingen Germany
| | - Gerrit Holighaus
- J.F. Blumenbach Institute of Zoology and Anthropology Animal Ecology Group University of Goettingen Goettingen Germany.,Forest Zoology and Forest Conservation University of Goettingen Goettingen Germany
| | - Marko Rohlfs
- J.F. Blumenbach Institute of Zoology and Anthropology Animal Ecology Group University of Goettingen Goettingen Germany.,Institute of Ecology, Population and Evolutionary Ecology Group University of Bremen Bremen Germany
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73
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Zhao JC, Wang YL, Zhang TY, Chen ZJ, Yang TM, Wu YY, Sun CP, Ma XC, Zhang YX. Indole diterpenoids from the endophytic fungus Drechmeria sp. as natural antimicrobial agents. PHYTOCHEMISTRY 2018; 148:21-28. [PMID: 29366852 DOI: 10.1016/j.phytochem.2018.01.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/08/2018] [Accepted: 01/13/2018] [Indexed: 06/07/2023]
Abstract
A fungal strain, Drechmeria sp., was isolated from the root of Panax notoginseng. Totally, seven new indole diterpenoids, drechmerins A-G (1-7), were isolated from the fermentation broth of Drechmeria sp. together with four known analogues (8-11). Their structures were determined on the basis of 1D and 2D NMR and electronic circular dichroism (ECD) spectroscopic analyses as well as theoretical calculations. All the isolated compounds were evaluated for their antimicrobial activities against Candida albicans, Staphylococcus aureus, Bacillus cereus, B. subtillis, Pseudomonas aeruginosa, and Klebsiella pneumonia, respectively. Drechmerin B (2) displayed antimicrobial activity against C. albicans with an MIC value of 12.5 μg/mL. Molecular docking was used to investigate interactions of peptide deformylase with compounds 1-3, 5-7, 9, and 10.
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Affiliation(s)
- Jian-Chao Zhao
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Ya-Li Wang
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, 110016, China; College of Pharmacy, College (Institute) of Integrative Medicine, Dalian Medical University, Dalian, 116044, China
| | - Tian-Yuan Zhang
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Zhong-Jian Chen
- Wenshan Sanqi Research Institute, Wenshan University, Wenshan, 663000, China
| | - Tian-Mei Yang
- Institute of Medicinal Plants, Yunnan Academy of Agricultural Sciences, Kunming, 650200, China
| | - Ying-Ying Wu
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Cheng-Peng Sun
- College of Pharmacy, College (Institute) of Integrative Medicine, Dalian Medical University, Dalian, 116044, China.
| | - Xiao-Chi Ma
- College of Pharmacy, College (Institute) of Integrative Medicine, Dalian Medical University, Dalian, 116044, China.
| | - Yi-Xuan Zhang
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, 110016, China.
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74
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Gerin D, González-Candelas L, Ballester AR, Pollastro S, De Miccolis Angelini RM, Faretra F. Functional Characterization of the alb1 Orthologue Gene in the Ochratoxigenic Fungus Aspergillus carbonarius (AC49 strain). Toxins (Basel) 2018. [PMID: 29534508 PMCID: PMC5869408 DOI: 10.3390/toxins10030120] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Aspergillus carbonarius, belonging to the group Nigri, is the main species responsible for contamination by ochratoxin A (OTA) in grapes and derivative products. OTA can accumulate in the mycelium and in black conidia of the fungus and released into the matrix. Here, we have deleted in A. carbonarius the alb1 orthologue gene of A. fumigatus, involved in melanin biosynthesis. Three A. carbonarius Δalb1 mutants were characterized for morphologic traits and OTA production on different media and temperatures. Δalb1 mutants showed a fawn color of conidia associated with a significant reduction of the conidiogenesis and a statistically significant increase (p ≤ 0.01) of total OTA production as compared to the wild type (WT) strain. The alb1 gene somehow affected OTA partitioning since in Δalb1 mutants OTA amount was lower in conidia and was more abundantly secreted into the medium as compared to the WT. On grape berries the Δalb1 mutants and the WT caused lesions with similar sizes but OTA amount in berry tissues was higher for the mutants. These results demonstrate that A. carbonarius conidia pigmentation is largely dependent on polyketide biosynthesis. The gene is not directly involved in virulence and its deletion affects morphological features and OTA production in the fungus.
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Affiliation(s)
- Donato Gerin
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, via Amendola 165/A, 70126 Bari, Italy.
| | - Luis González-Candelas
- Instituto de Agroquímica y Tecnología de Alimentos, IATA-CSIC, Calle Agustín Escardino 7, Paterna, 46980 Valencia, Spain.
| | - Ana-Rosa Ballester
- Instituto de Agroquímica y Tecnología de Alimentos, IATA-CSIC, Calle Agustín Escardino 7, Paterna, 46980 Valencia, Spain.
| | - Stefania Pollastro
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, via Amendola 165/A, 70126 Bari, Italy.
- SELGE Network of Public Research Laboratories, via Amendola 165/A, 70126 Bari, Italy.
| | - Rita Milvia De Miccolis Angelini
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, via Amendola 165/A, 70126 Bari, Italy.
- SELGE Network of Public Research Laboratories, via Amendola 165/A, 70126 Bari, Italy.
| | - Francesco Faretra
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, via Amendola 165/A, 70126 Bari, Italy.
- SELGE Network of Public Research Laboratories, via Amendola 165/A, 70126 Bari, Italy.
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El Hajj Assaf C, Snini SP, Tadrist S, Bailly S, Naylies C, Oswald IP, Lorber S, Puel O. Impact of veA on the development, aggressiveness, dissemination and secondary metabolism of Penicillium expansum. MOLECULAR PLANT PATHOLOGY 2018; 19:1971-1983. [PMID: 29517851 PMCID: PMC6638001 DOI: 10.1111/mpp.12673] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/02/2018] [Accepted: 03/03/2018] [Indexed: 05/18/2023]
Abstract
Penicillium expansum, the causal agent of blue mould disease, produces the mycotoxins patulin and citrinin amongst other secondary metabolites. Secondary metabolism is associated with fungal development, which responds to numerous biotic and abiotic external triggers. The global transcription factor VeA plays a key role in the coordination of secondary metabolism and differentiation processes in many fungal species. The specific role of VeA in P. expansum remains unknown. A null mutant PeΔveA strain and a complemented PeΔveA:veA strain were generated in P. expansum and their pathogenicity on apples was studied. Like the wild-type and the complemented strains, the null mutant PeΔveA strain was still able to sporulate and to colonize apples, but at a lower rate. However, it could not form coremia either in vitro or in vivo, thus limiting its dissemination from natural substrates. The impact of veA on the expression of genes encoding proteins involved in the production of patulin, citrinin and other secondary metabolites was evaluated. The disruption of veA drastically reduced the production of patulin and citrinin on synthetic media, associated with a marked down-regulation of all genes involved in the biosynthesis of the two mycotoxins. Moreover, the null mutant PeΔveA strain was unable to produce patulin on apples. The analysis of gene expression revealed a global impact on secondary metabolism, as 15 of 35 backbone genes showed differential regulation on two different media. These findings support the hypothesis that VeA contributes to the pathogenicity of P. expansum and modulates its secondary metabolism.
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Affiliation(s)
- Christelle El Hajj Assaf
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP‐Purpan, UPS31027 ToulouseFrance
- Flanders Research Institute for Agricultural, Fisheries and Food (ILVO), Technology and Food Science UnitMelle 9090Belgium
| | - Selma P. Snini
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP‐Purpan, UPS31027 ToulouseFrance
- Present address:
Université de Toulouse, Laboratoire de Génie Chimique, CNRS, INPT, UPSToulouseFrance
| | - Souria Tadrist
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP‐Purpan, UPS31027 ToulouseFrance
| | - Sylviane Bailly
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP‐Purpan, UPS31027 ToulouseFrance
| | - Claire Naylies
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP‐Purpan, UPS31027 ToulouseFrance
| | - Isabelle P. Oswald
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP‐Purpan, UPS31027 ToulouseFrance
| | - Sophie Lorber
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP‐Purpan, UPS31027 ToulouseFrance
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP‐Purpan, UPS31027 ToulouseFrance
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76
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Martino E, Morin E, Grelet GA, Kuo A, Kohler A, Daghino S, Barry KW, Cichocki N, Clum A, Dockter RB, Hainaut M, Kuo RC, LaButti K, Lindahl BD, Lindquist EA, Lipzen A, Khouja HR, Magnuson J, Murat C, Ohm RA, Singer SW, Spatafora JW, Wang M, Veneault-Fourrey C, Henrissat B, Grigoriev IV, Martin FM, Perotto S. Comparative genomics and transcriptomics depict ericoid mycorrhizal fungi as versatile saprotrophs and plant mutualists. THE NEW PHYTOLOGIST 2018; 217:1213-1229. [PMID: 29315638 DOI: 10.1111/nph.14974] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Accepted: 11/25/2017] [Indexed: 05/10/2023]
Abstract
Some soil fungi in the Leotiomycetes form ericoid mycorrhizal (ERM) symbioses with Ericaceae. In the harsh habitats in which they occur, ERM plant survival relies on nutrient mobilization from soil organic matter (SOM) by their fungal partners. The characterization of the fungal genetic machinery underpinning both the symbiotic lifestyle and SOM degradation is needed to understand ERM symbiosis functioning and evolution, and its impact on soil carbon (C) turnover. We sequenced the genomes of the ERM fungi Meliniomyces bicolor, M. variabilis, Oidiodendron maius and Rhizoscyphus ericae, and compared their gene repertoires with those of fungi with different lifestyles (ecto- and orchid mycorrhiza, endophytes, saprotrophs, pathogens). We also identified fungal transcripts induced in symbiosis. The ERM fungal gene contents for polysaccharide-degrading enzymes, lipases, proteases and enzymes involved in secondary metabolism are closer to those of saprotrophs and pathogens than to those of ectomycorrhizal symbionts. The fungal genes most highly upregulated in symbiosis are those coding for fungal and plant cell wall-degrading enzymes (CWDEs), lipases, proteases, transporters and mycorrhiza-induced small secreted proteins (MiSSPs). The ERM fungal gene repertoire reveals a capacity for a dual saprotrophic and biotrophic lifestyle. This may reflect an incomplete transition from saprotrophy to the mycorrhizal habit, or a versatile life strategy similar to fungal endophytes.
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Affiliation(s)
- Elena Martino
- Department of Life Sciences and Systems Biology, University of Turin, Turin, 10125, Italy
- INRA, UMR 1136 INRA-Université de Lorraine 'Interactions Arbres/Microorganismes', Laboratoire d'Excellence ARBRE, Centre INRA-Lorraine, 54280, Champenoux, France
| | - Emmanuelle Morin
- INRA, UMR 1136 INRA-Université de Lorraine 'Interactions Arbres/Microorganismes', Laboratoire d'Excellence ARBRE, Centre INRA-Lorraine, 54280, Champenoux, France
| | - Gwen-Aëlle Grelet
- Manaaki Whenua - Landcare Research, Ecosystems and Global Change Team, Gerald Street, PO Box 69040, Lincoln, 7640, New Zealand
| | - Alan Kuo
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Annegret Kohler
- INRA, UMR 1136 INRA-Université de Lorraine 'Interactions Arbres/Microorganismes', Laboratoire d'Excellence ARBRE, Centre INRA-Lorraine, 54280, Champenoux, France
| | - Stefania Daghino
- Department of Life Sciences and Systems Biology, University of Turin, Turin, 10125, Italy
| | - Kerrie W Barry
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Nicolas Cichocki
- INRA, UMR 1136 INRA-Université de Lorraine 'Interactions Arbres/Microorganismes', Laboratoire d'Excellence ARBRE, Centre INRA-Lorraine, 54280, Champenoux, France
| | - Alicia Clum
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Rhyan B Dockter
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Matthieu Hainaut
- Architecture et Fonction des Macromolécules Biologiques, UMR7257 Centre National de la Recherche Scientifique - Aix-Marseille Université, Case 932, 163 Avenue de Luminy, Marseille, 13288, France
- INRA, USC 1408 AFMB, Marseille, 13288, France
| | - Rita C Kuo
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Kurt LaButti
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Björn D Lindahl
- Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, 75007, Sweden
| | - Erika A Lindquist
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Anna Lipzen
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | | | - Jon Magnuson
- Pacific Northwest National Laboratory, Chemical and Biological Process Development Group, Richland, WA, 99354, USA
| | - Claude Murat
- INRA, UMR 1136 INRA-Université de Lorraine 'Interactions Arbres/Microorganismes', Laboratoire d'Excellence ARBRE, Centre INRA-Lorraine, 54280, Champenoux, France
| | - Robin A Ohm
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA
- Microbiology, Department of Biology, Utrecht University, 3508, TB Utrecht, the Netherlands
| | - Steven W Singer
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Joseph W Spatafora
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA
| | - Mei Wang
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Claire Veneault-Fourrey
- INRA, UMR 1136 INRA-Université de Lorraine 'Interactions Arbres/Microorganismes', Laboratoire d'Excellence ARBRE, Centre INRA-Lorraine, 54280, Champenoux, France
- Laboratoire d'Excellence ARBRE, Faculté des Sciences et Technologies, UMR 1136 INRA-Université de Lorraine 'Interactions Arbres/Microorganismes', Université de Lorraine, Campus Aiguillettes, BP 70239, Vandoeuvre les Nancy cedex, 54506, France
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques, UMR7257 Centre National de la Recherche Scientifique - Aix-Marseille Université, Case 932, 163 Avenue de Luminy, Marseille, 13288, France
- INRA, USC 1408 AFMB, Marseille, 13288, France
- Department of Biological Sciences, King Abdulaziz University - KSA, Jeddah, 21589, Saudi Arabia
| | - Igor V Grigoriev
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Francis M Martin
- INRA, UMR 1136 INRA-Université de Lorraine 'Interactions Arbres/Microorganismes', Laboratoire d'Excellence ARBRE, Centre INRA-Lorraine, 54280, Champenoux, France
| | - Silvia Perotto
- Department of Life Sciences and Systems Biology, University of Turin, Turin, 10125, Italy
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Sarmiento‐Villamil JL, García‐Pedrajas NE, Baeza‐Montañez L, García‐Pedrajas MD. The APSES transcription factor Vst1 is a key regulator of development in microsclerotium- and resting mycelium-producing Verticillium species. MOLECULAR PLANT PATHOLOGY 2018; 19:59-76. [PMID: 27696683 PMCID: PMC6638171 DOI: 10.1111/mpp.12496] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 09/28/2016] [Accepted: 09/28/2016] [Indexed: 05/12/2023]
Abstract
Plant pathogens of the genus Verticillium pose a threat to many important crops worldwide. They are soil-borne fungi which invade the plant systemically, causing wilt symptoms. We functionally characterized the APSES family transcription factor Vst1 in two Verticillium species, V. dahliae and V. nonalfalfae, which produce microsclerotia and melanized hyphae as resistant structures, respectively. We found that, in V. dahliae Δvst1 strains, microsclerotium biogenesis stalled after an initial swelling of hyphal cells and cultures were never pigmented. In V. nonalfalfae Δvst1, melanized hyphae were also absent. These results suggest that Vst1 controls melanin biosynthesis independent of its role in morphogenesis. The absence of vst1 also had a great impact on sporulation in both species, affecting the generation of the characteristic verticillate conidiophore structure and sporulation rates in liquid medium. In contrast with these key roles in development, Vst1 activity was dispensable for virulence. We performed a microarray analysis comparing global transcription patterns of wild-type and Δvst1 in V. dahliae. G-protein/cyclic adenosine monophosphate (G-protein/cAMP) signalling and mitogen-activated protein kinase (MAPK) cascades are known to regulate fungal morphogenesis and virulence. The microarray analysis revealed a negative interaction of Vst1 with G-protein/cAMP signalling and a positive interaction with MAPK signalling. This analysis also identified Rho signalling as a potential regulator of morphogenesis in V. dahliae, positively interacting with Vst1. Furthermore, it exposed the association of secondary metabolism and development in this species, identifying Vst1 as a potential co-regulator of both processes. Characterization of the putative Vst1 targets identified in this study will aid in the dissection of specific aspects of development.
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Affiliation(s)
- Jorge L. Sarmiento‐Villamil
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’ ‐ Universidad de Málaga ‐ Consejo Superior de Investigaciones Científicas (IHSM‐UMA‐CSIC), Estación Experimental ‘La Mayora’, 29750 Algarrobo‐CostaMálagaSpain
| | - Nicolás E. García‐Pedrajas
- Department of Computing and Numerical Analysis, C2 Building 3rd FloorCampus Universitario de RabanalesCórdoba14071Spain
| | - Lourdes Baeza‐Montañez
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’ ‐ Universidad de Málaga ‐ Consejo Superior de Investigaciones Científicas (IHSM‐UMA‐CSIC), Estación Experimental ‘La Mayora’, 29750 Algarrobo‐CostaMálagaSpain
| | - María D. García‐Pedrajas
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’ ‐ Universidad de Málaga ‐ Consejo Superior de Investigaciones Científicas (IHSM‐UMA‐CSIC), Estación Experimental ‘La Mayora’, 29750 Algarrobo‐CostaMálagaSpain
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78
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Šimončicová J, Kaliňáková B, Kryštofová S. Aflatoxins: biosynthesis, prevention and eradication. ACTA CHIMICA SLOVACA 2017. [DOI: 10.1515/acs-2017-0021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Abstract
Filamentous fungi belonging to Aspergilli genera produce many compounds through various biosynthetic pathways. These compounds include a spectrum of products with beneficial medical properties (lovastatin) as well as those that are toxic and/or carcinogenic which are called mycotoxins. Aspergillus flavus, one of the most abundant soil-borne fungi, is a saprobe that is able growing on many organic nutrient sources, such as peanuts, corn and cotton seed. In many countries, food contamination by A. flavus is a huge problem, mainly due to the production of the most toxic and carcinogenic compounds known as aflatoxins. In this paper, we briefly cover current progress in aflatoxin biosynthesis and regulation, pre- and postharvest preventive measures, and decontamination procedures.
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Affiliation(s)
- Juliana Šimončicová
- Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava , Slovakia
| | - Barbora Kaliňáková
- Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava Slovakia
| | - Svetlana Kryštofová
- Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava Slovakia
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79
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Etxebeste O, Espeso EA. Neurons show the path: tip-to-nucleus communication in filamentous fungal development and pathogenesis. FEMS Microbiol Rev 2017; 40:610-24. [PMID: 27587717 DOI: 10.1093/femsre/fuw021] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2016] [Indexed: 01/11/2023] Open
Abstract
Multiple fungal species penetrate substrates and accomplish host invasion through the fast, permanent and unidirectional extension of filamentous cells known as hyphae. Polar growth of hyphae results, however, in a significant increase in the distance between the polarity site, which also receives the earliest information about ambient conditions, and nuclei, where adaptive responses are executed. Recent studies demonstrate that these long distances are overcome by signal transduction pathways which convey sensory information from the polarity site to nuclei, controlling development and pathogenesis. The present review compares the striking connections of the mechanisms for long-distance communication in hyphae with those from neurons, and discusses the importance of their study in order to understand invasion and dissemination processes of filamentous fungi, and design strategies for developmental control in the future.
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Affiliation(s)
- Oier Etxebeste
- Biochemistry II laboratory, Department of Applied Chemistry, Faculty of Chemistry, University of the Basque Country (UPV/EHU), 20018 San Sebastian, Spain
| | - Eduardo A Espeso
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
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80
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Yao G, Zhang F, Nie X, Wang X, Yuan J, Zhuang Z, Wang S. Essential APSES Transcription Factors for Mycotoxin Synthesis, Fungal Development, and Pathogenicity in Aspergillus flavus. Front Microbiol 2017; 8:2277. [PMID: 29209291 PMCID: PMC5702001 DOI: 10.3389/fmicb.2017.02277] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 11/06/2017] [Indexed: 02/04/2023] Open
Abstract
Aflatoxins are a potent carcinogenic mycotoxin and has become a research model of fungal secondary metabolism (SM). Via systematically investigating the APSES transcription factors (TFs), two APSES proteins were identified: AfRafA and AfStuA. These play central roles in the synthesis of mycotoxins including aflatoxin and cyclopiazonic acid, and fungal development and are consequently central to the pathogenicity of the aflatoxigenic A. flavus. Loss of AfRafA not only dramatically suppressed aflatoxin cluster expression, subsequently reducing toxin synthesis both in vitro and in vivo, but also impaired conidia and sclerotia development. More importantly, aflatoxin biosynthesis as well as conidia and sclerotia development were fully blocked in ΔAfStuA. In addition, our results supported that AfStuA regulated the aflatoxin synthesis in an AflR-dependent manner. Intriguingly, it was revealed that AfRafA and AfStuA exert an antagonistic role in the regulation of biosynthesis of cyclopiazonic acid. In summary, two global transcriptional regulators for fungal development, mycotoxin production, and seed pathogenicity of the A. flavus system have been established. The two novel regulators of mycotoxins are promising targets for future plant breeding and for the development of fungicides.
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Affiliation(s)
- Guangshan Yao
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Feng Zhang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xinyi Nie
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiuna Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jun Yuan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhenhong Zhuang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
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81
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Bazafkan H, Beier S, Stappler E, Böhmdorfer S, Oberlerchner JT, Sulyok M, Schmoll M. SUB1 has photoreceptor dependent and independent functions in sexual development and secondary metabolism in Trichoderma reesei. Mol Microbiol 2017; 106:742-759. [PMID: 28925526 DOI: 10.1111/mmi.13842] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2017] [Indexed: 12/17/2022]
Abstract
Light dependent processes are involved in the regulation of growth, development and enzyme production in Trichoderma reesei. The photoreceptors BLR1, BLR2 and ENV1 exert crucial functions in these processes. We analyzed the involvement of the transcription factor SUB1 in sexual development as well as secondary metabolism and its position in the light signaling cascade. SUB1 influences growth and in contrast to its homologue in N. crassa, SUB1 is not essential for fruiting body formation and male fertility in T. reesei, but required for female fertility. Accordingly, SUB1 is involved in the regulation of the pheromone system of T. reesei. Female sterility of mutants lacking env1 is rescued in triple mutants of blr1, blr2 and env1, but not in double mutants of these genes. Confrontation of strains lacking sub1 results in growth arrest prior to contact of the potential mating partners. This effect is at least in part due to altered secondary metabolite production. Additionally, together with BLR1 and BLR2, SUB1 is essential for spore pigmentation and transcription of pks4, and secondary metabolism is regulated by SUB1 in a light- and nutrient dependent manner. Our results hence indicate rewiring of several pathways targeted by SUB1 in T. reesei.
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Affiliation(s)
- Hoda Bazafkan
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz Strasse 24, 3430 Tulln, Austria
| | - Sabrina Beier
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz Strasse 24, 3430 Tulln, Austria
| | - Eva Stappler
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz Strasse 24, 3430 Tulln, Austria
| | - Stefan Böhmdorfer
- Department of Chemistry, Division of Chemistry of Renewable Resources, University of Natural Resources and Life Sciences Vienna, Konrad-Lorenz-Straße 24, 3430 Tulln, Austria
| | - Josua T Oberlerchner
- Department of Chemistry, Division of Chemistry of Renewable Resources, University of Natural Resources and Life Sciences Vienna, Konrad-Lorenz-Straße 24, 3430 Tulln, Austria
| | - Michael Sulyok
- Department for Agrobiotechnology (IFA-Tulln), Center for Analytical Chemistry, University of Natural Resources and Life Sciences Vienna, Konrad-Lorenz-Straße 20, 3430 Tulln, Austria
| | - Monika Schmoll
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz Strasse 24, 3430 Tulln, Austria
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82
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The Aspergillus flavus Homeobox Gene, hbx1, is Required for Development and Aflatoxin Production. Toxins (Basel) 2017; 9:toxins9100315. [PMID: 29023405 PMCID: PMC5666362 DOI: 10.3390/toxins9100315] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/06/2017] [Accepted: 10/09/2017] [Indexed: 11/17/2022] Open
Abstract
Homeobox proteins, a class of well conserved transcription factors, regulate the expression of targeted genes, especially those involved in development. In filamentous fungi, homeobox genes are required for normal conidiogenesis and fruiting body formation. In the present study, we identified eight homeobox (hbx) genes in the aflatoxin-producing ascomycete, Aspergillus flavus, and determined their respective role in growth, conidiation and sclerotial production. Disruption of seven of the eight genes had little to no effect on fungal growth and development. However, disruption of the homeobox gene AFLA_069100, designated as hbx1, in two morphologically different A. flavus strains, CA14 and AF70, resulted in complete loss of production of conidia and sclerotia as well as aflatoxins B1 and B2, cyclopiazonic acid and aflatrem. Microscopic examination showed that the Δhbx1 mutants did not produce conidiophores. The inability of Δhbx1 mutants to produce conidia was related to downregulation of brlA (bristle) and abaA (abacus), regulatory genes for conidiophore development. These mutants also had significant downregulation of the aflatoxin pathway biosynthetic genes aflC, aflD, aflM and the cluster-specific regulatory gene, aflR. Our results demonstrate that hbx1 not only plays a significant role in controlling A. flavus development but is also critical for the production of secondary metabolites, such as aflatoxins.
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83
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Structural modification of cuminaldehyde thiosemicarbazone increases inhibition specificity toward aflatoxin biosynthesis and sclerotia development in Aspergillus flavus. Appl Microbiol Biotechnol 2017; 101:6683-6696. [PMID: 28725928 DOI: 10.1007/s00253-017-8426-y] [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] [Received: 02/17/2017] [Revised: 06/29/2017] [Accepted: 07/02/2017] [Indexed: 01/18/2023]
Abstract
Aspergillus flavus is an opportunistic mold that represents a serious threat for human and animal health due to its ability to synthesize and release, on food and feed commodities, different toxic secondary metabolites. Among them, aflatoxin B1 is one of the most dangerous since it is provided with a strong cancerogenic and mutagenic activity. Controlling fungal contamination on the different crops that may host A. flavus is considered a priority by sanitary authorities of an increasing number of countries due also to the fact that, owing to global temperature increase, the geographic areas that are expected to be prone to experience sudden A. flavus outbreaks are widening. Among the different pre- and post-harvest strategies that may be put forward in order to prevent fungal and/or mycotoxin contamination, fungicides are still considered a prominent weapon. We have here analyzed different structural modifications of a natural-derived compound (cuminaldehyde thiosemicarbazone) for their fungistatic and anti-aflatoxigenic activity. In particular, we have focused our attention on one of the compound that presented a prominent anti-aflatoxin specificity, and performed a set of physiological and molecular analyses, taking also advantage of yeast (Saccharomyces cerevisiae) cell as an experimental model.
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84
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Röhrig J, Yu Z, Chae KS, Kim JH, Han KH, Fischer R. TheAspergillus nidulansVelvet-interacting protein, VipA, is involved in light-stimulated heme biosynthesis. Mol Microbiol 2017; 105:825-838. [DOI: 10.1111/mmi.13739] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 06/21/2017] [Accepted: 06/21/2017] [Indexed: 01/25/2023]
Affiliation(s)
- Julian Röhrig
- Institute for Applied Biosciences, Dept. of Microbiology, Karlsruhe Institute of Technology (KIT) - South Campus; Fritz-Haber-Weg 4 Karlsruhe D-76131 Germany
| | - Zhenzhong Yu
- Institute for Applied Biosciences, Dept. of Microbiology, Karlsruhe Institute of Technology (KIT) - South Campus; Fritz-Haber-Weg 4 Karlsruhe D-76131 Germany
| | - Keon-Sang Chae
- Department of Molecular Biology; Chonbuk National University; Jeonju South Korea
| | - Jong-Hwa Kim
- Department of Pharmaceutical Engineering; Woosuk University; Wanju Jeonbuk 565-701 South Korea
| | - Kap-Hoon Han
- Department of Pharmaceutical Engineering; Woosuk University; Wanju Jeonbuk 565-701 South Korea
| | - Reinhard Fischer
- Institute for Applied Biosciences, Dept. of Microbiology, Karlsruhe Institute of Technology (KIT) - South Campus; Fritz-Haber-Weg 4 Karlsruhe D-76131 Germany
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Zhi QQ, Li JY, Liu QY, He ZM. A cytosine methyltransferase ortholog dmtA is involved in the sensitivity of Aspergillus flavus to environmental stresses. Fungal Biol 2017; 121:501-514. [DOI: 10.1016/j.funbio.2017.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 01/21/2017] [Accepted: 02/01/2017] [Indexed: 01/05/2023]
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86
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Differential Control of Asexual Development and Sterigmatocystin Biosynthesis by a Novel Regulator in Aspergillus nidulans. Sci Rep 2017; 7:46340. [PMID: 28422127 PMCID: PMC5396049 DOI: 10.1038/srep46340] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/15/2017] [Indexed: 11/08/2022] Open
Abstract
The filamentous fungus Aspergillus nidulans primarily reproduces by forming asexual spores called conidia and produces the mycotoxin sterigmatocystin (ST), the penultimate precursor of aflatoxins. It has been known that asexual development and ST production are tightly co-regulated by various regulatory inputs. Here, we report that the novel regulator AslA with a C2H2 domain oppositely regulates development and ST biosynthesis. Nullifying aslA resulted in defective conidiation and reduced expression of brlA encoding a key activator of asexual development, which indicates that AslA functions as an upstream activator of brlA expression. aslA deletion additionally caused enhanced ST production and expression of aflR encoding a transcriptional activator for ST biosynthetic genes, suggesting that AslA functions as an upstream negative regulator of aflR. Cellular and molecular studies showed that AslA has a trans-activation domain and is localized in the nuclei of vegetative and developing cells but not in spores, indicating that AslA is likely a transcription factor. Introduction of the aslA homologs from distantly-related aspergilli complemented the defects caused by aslA null mutation in A. nidulans, implying a functional conservancy of AslA. We propose that AslA is a novel regulator that may act at the split control point of the developmental and metabolic pathways.
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87
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Soukup AA, Fischer GJ, Luo J, Keller NP. The Aspergillus nidulans Pbp1 homolog is required for normal sexual development and secondary metabolism. Fungal Genet Biol 2017; 100:13-21. [PMID: 28089630 PMCID: PMC5337145 DOI: 10.1016/j.fgb.2017.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/02/2017] [Accepted: 01/08/2017] [Indexed: 01/18/2023]
Abstract
P bodies and stress granules are RNA-containing structures governing mRNA degradation and translational arrest, respectively. Saccharomyces cerevisiae Pbp1 protein localizes to stress granules and promotes their formation and is involved in proper polyadenylation, suppression of RNA-DNA hybrids, and preventing aberrant rDNA recombination. A genetic screen for Aspergillus nidulans mutants aberrant in secondary metabolism identified the Pbp1 homolog, PbpA. Using Dcp1 (mRNA decapping) as a marker for P-body formation and FabM (Pab1, poly-A binding protein) to track stress granule accumulation, we examine the dynamics of RNA granule formation in A. nidulans cells lacking pub1, edc3, and pbpA. Although PbpA acts as a functional homolog of yeast PBP1, PbpA had little impact on either P-body or stress granule formation in A. nidulans in contrast to Pub1 and Edc3. However, we find that PbpA is critical for sexual development and its loss increases the production of some secondary metabolites including the carcinogen sterigmatocystin.
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Affiliation(s)
- Alexandra A Soukup
- Department of Genetics, University of Wisconsin-Madison, WI, United States
| | - Gregory J Fischer
- Department of Genetics, University of Wisconsin-Madison, WI, United States
| | - Jerry Luo
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, WI, United States
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, WI, United States; Department of Bacteriology, University of Wisconsin-Madison, WI, United States.
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88
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Li Y, He Y, Li X, Fasoyin OE, Hu Y, Liu Y, Yuan J, Zhuang Z, Wang S. Histone Methyltransferase aflrmtA gene is involved in the morphogenesis, mycotoxin biosynthesis, and pathogenicity of Aspergillus flavus. Toxicon 2017; 127:112-121. [PMID: 28109854 DOI: 10.1016/j.toxicon.2017.01.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 01/15/2017] [Accepted: 01/17/2017] [Indexed: 02/08/2023]
Abstract
Arginine methyltransferases catalyze the posttranslational methylation of arginine, which is involved in a range of important biological processes. aflrmtA gene, an arginine methyltransferase was deleted from Aspergillus flavus in this study by homologous recombination. In morphogenesis assay, aflrmtA was found to down-regulate conidiation by regulating the activity of brlA and abaA genes. It was also found to increase sclerotia formation by up-regulating the expression of nsdC and nsdD genes. In mycotoxin biosynthesis, aflrmtA gene was found to significantly up-regulate the biosynthesis of AFB1 in PDA and PDB media by improving the expression of aflR, aflC and aflK, but it was of no effect in YES medium. aflrmtA was further found to be an important regulator of response to plasma membrane lesion, osmotic, and H2O2 - induced oxidative stresses. In pathogenicity analysis, aflrmtA was found to repress conidiation and up-regulate the AFB1 biosynthesis of A. flavus on peanut and corn seeds and also the activities of protease and lipase, but the activity of amylase was down-regulated. It was concluded that aflrmtA gene played important roles in the morphogenesis, mycotoxin biosynthesis and pathogenicity of A. flavus, and it could be a potential target in the prevention and control of crop contamination by A. flavus.
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Affiliation(s)
- Yu Li
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yizi He
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xing Li
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Opemipo Esther Fasoyin
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yule Hu
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yaju Liu
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jun Yuan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zhenhong Zhuang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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89
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Fountain JC, Bajaj P, Nayak SN, Yang L, Pandey MK, Kumar V, Jayale AS, Chitikineni A, Lee RD, Kemerait RC, Varshney RK, Guo B. Responses of Aspergillus flavus to Oxidative Stress Are Related to Fungal Development Regulator, Antioxidant Enzyme, and Secondary Metabolite Biosynthetic Gene Expression. Front Microbiol 2016; 7:2048. [PMID: 28066369 PMCID: PMC5175028 DOI: 10.3389/fmicb.2016.02048] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Accepted: 12/06/2016] [Indexed: 12/21/2022] Open
Abstract
The infection of maize and peanut with Aspergillus flavus and subsequent contamination with aflatoxin pose a threat to global food safety and human health, and is exacerbated by drought stress. Drought stress-responding compounds such as reactive oxygen species (ROS) are associated with fungal stress responsive signaling and secondary metabolite production, and can stimulate the production of aflatoxin by A. flavus in vitro. These secondary metabolites have been shown to possess diverse functions in soil-borne fungi including antibiosis, competitive inhibition of other microbes, and abiotic stress alleviation. Previously, we observed that isolates of A. flavus showed differences in oxidative stress tolerance which correlated with their aflatoxin production capabilities. In order to better understand these isolate-specific oxidative stress responses, we examined the transcriptional responses of field isolates of A. flavus with varying levels of aflatoxin production (NRRL3357, AF13, and Tox4) to H2O2-induced oxidative stress using an RNA sequencing approach. These isolates were cultured in an aflatoxin-production conducive medium amended with various levels of H2O2. Whole transcriptomes were sequenced using an Illumina HiSeq platform with an average of 40.43 million filtered paired-end reads generated for each sample. The obtained transcriptomes were then used for differential expression, gene ontology, pathway, and co-expression analyses. Isolates which produced higher levels of aflatoxin tended to exhibit fewer differentially expressed genes than isolates with lower levels of production. Genes found to be differentially expressed in response to increasing oxidative stress included antioxidant enzymes, primary metabolism components, antibiosis-related genes, and secondary metabolite biosynthetic components specifically for aflatoxin, aflatrem, and kojic acid. The expression of fungal development-related genes including aminobenzoate degradation genes and conidiation regulators were found to be regulated in response to increasing stress. Aflatoxin biosynthetic genes and antioxidant enzyme genes were also found to be co-expressed and highly correlated with fungal biomass under stress. This suggests that these secondary metabolites may be produced as part of coordinated oxidative stress responses in A. flavus along with antioxidant enzyme gene expression and developmental regulation.
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Affiliation(s)
- Jake C Fountain
- Department of Plant Pathology, University of GeorgiaTifton, GA, USA; United States Department of Agriculture, Agricultural Research Service Crop Protection and Management Research UnitTifton, GA, USA
| | - Prasad Bajaj
- International Crop Research Institute for the Semi-Arid Tropics Hyderabad, India
| | - Spurthi N Nayak
- International Crop Research Institute for the Semi-Arid Tropics Hyderabad, India
| | - Liming Yang
- Department of Plant Pathology, University of GeorgiaTifton, GA, USA; United States Department of Agriculture, Agricultural Research Service Crop Protection and Management Research UnitTifton, GA, USA
| | - Manish K Pandey
- International Crop Research Institute for the Semi-Arid Tropics Hyderabad, India
| | - Vinay Kumar
- International Crop Research Institute for the Semi-Arid Tropics Hyderabad, India
| | - Ashwin S Jayale
- International Crop Research Institute for the Semi-Arid Tropics Hyderabad, India
| | - Anu Chitikineni
- International Crop Research Institute for the Semi-Arid Tropics Hyderabad, India
| | - Robert D Lee
- Department of Crop and Soil Sciences, University of Georgia Tifton, GA, USA
| | - Robert C Kemerait
- Department of Plant Pathology, University of Georgia Tifton, GA, USA
| | - Rajeev K Varshney
- International Crop Research Institute for the Semi-Arid Tropics Hyderabad, India
| | - Baozhu Guo
- United States Department of Agriculture, Agricultural Research Service Crop Protection and Management Research Unit Tifton, GA, USA
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90
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Regulation of Secondary Metabolism by the Velvet Complex Is Temperature-Responsive in Aspergillus. G3-GENES GENOMES GENETICS 2016; 6:4023-4033. [PMID: 27694115 PMCID: PMC5144971 DOI: 10.1534/g3.116.033084] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Sensing and responding to environmental cues is critical to the lifestyle of filamentous fungi. How environmental variation influences fungi to produce a wide diversity of ecologically important secondary metabolites (SMs) is not well understood. To address this question, we first examined changes in global gene expression of the opportunistic human pathogen, Aspergillus fumigatus, after exposure to different temperature conditions. We found that 11 of the 37 SM gene clusters in A. fumigatus were expressed at higher levels at 30° than at 37°. We next investigated the role of the light-responsive Velvet complex in environment-dependent gene expression by examining temperature-dependent transcription profiles in the absence of two key members of the Velvet protein complex, VeA and LaeA. We found that the 11 temperature-regulated SM gene clusters required VeA at 37° and LaeA at both 30 and 37° for wild-type levels of expression. Interestingly, four SM gene clusters were regulated by VeA at 37° but not at 30°, and two additional ones were regulated by VeA at both temperatures but were substantially less so at 30°, indicating that the role of VeA and, more generally of the Velvet complex, in the regulation of certain SM gene clusters is temperature-dependent. Our findings support the hypothesis that fungal secondary metabolism is regulated by an intertwined network of transcriptional regulators responsive to multiple environmental factors.
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91
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Interactions between Melanin Enzymes and Their Atypical Recruitment to the Secretory Pathway by Palmitoylation. mBio 2016; 7:mBio.01925-16. [PMID: 27879337 PMCID: PMC5120144 DOI: 10.1128/mbio.01925-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Melanins are biopolymers that confer coloration and protection to the host organism against biotic or abiotic insults. The level of protection offered by melanin depends on its biosynthesis and its subcellular localization. Previously, we discovered that Aspergillus fumigatus compartmentalizes melanization in endosomes by recruiting all melanin enzymes to the secretory pathway. Surprisingly, although two laccases involved in the late steps of melanization are conventional secretory proteins, the four enzymes involved in the early steps of melanization lack a signal peptide or a transmembrane domain and are thus considered “atypical” secretory proteins. In this work, we found interactions among melanin enzymes and all melanin enzymes formed protein complexes. Surprisingly, the formation of protein complexes by melanin enzymes was not critical for their trafficking to the endosomal system. By palmitoylation profiling and biochemical analyses, we discovered that all four early melanin enzymes were strongly palmitoylated during conidiation. However, only the polyketide synthase (PKS) Alb1 was strongly palmitoylated during both vegetative hyphal growth and conidiation when constitutively expressed alone. This posttranslational lipid modification correlates the endosomal localization of all early melanin enzymes. Intriguingly, bioinformatic analyses predict that palmitoylation is a common mechanism for potential membrane association of polyketide synthases (PKSs) and nonribosomal peptide synthetases (NRPSs) in A. fumigatus. Our findings indicate that protein-protein interactions facilitate melanization by metabolic channeling, while posttranslational lipid modifications help recruit the atypical enzymes to the secretory pathway, which is critical for compartmentalization of secondary metabolism. Subcellular compartmentalization is increasingly recognized as an important aspect of fungal secondary metabolism. It facilitates sequential enzymatic reactions, provides mobility for enzymes and metabolites, and offers protection against self-toxification. However, how compartmentalization is achieved remains unclear given that the majority of enzymes encoded by secondary metabolism gene clusters are predicted to be cytosolic proteins. Through studying melanization in Aspergillus, we previously found that all enzymes involved in the early steps of melanization are atypical secretory proteins. Here, we discovered physical interactions among melanin enzymes. However, it was the posttranslational palmitoylation rather than the physical interaction that was responsible for their recruitment to the secretory pathway. Intriguingly, palmitoylation is likely a common mechanism for potential membrane association of polyketide synthases (PKSs) and nonribosomal peptide synthetases (NRPSs) in A. fumigatus. Collectively, our findings suggest that posttranslational lipid modification helps direct secondary metabolism to defined organelles for biosynthesis and trafficking.
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92
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Chettri P, Bradshaw RE. LaeA negatively regulates dothistromin production in the pine needle pathogen Dothistroma septosporum. Fungal Genet Biol 2016; 97:24-32. [PMID: 27818262 DOI: 10.1016/j.fgb.2016.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 10/30/2016] [Accepted: 11/01/2016] [Indexed: 01/03/2023]
Abstract
In filamentous fungi both pathway-specific and global regulators regulate genes involved in the biosynthesis of secondary metabolites. LaeA is a global regulator that was named for its mutant phenotype, loss of aflR expression, due to its effect on the aflatoxin-pathway regulator AflR in Aspergillus spp. The pine needle pathogen Dothistroma septosporum produces a polyketide virulence factor, dothistromin, that is chemically related to aflatoxin and whose pathway genes are also regulated by an ortholog of AflR. However, dothistromin biosynthesis is distinctive because it is switched on during early (rather than late) exponential growth phase and the genes are dispersed in six loci across one chromosome instead of being clustered. It was therefore of interest to determine whether the function of the global regulator LaeA is conserved in D. septosporum. To address this question, a LaeA ortholog (DsLaeA) was identified and its function analyzed in D. septosporum. In contrast to aflatoxin production in Aspergillus spp., deletion of DsLaeA resulted in enhanced dothistromin production and increased expression of the pathway regulatory gene DsAflR. Although expression of other putative secondary metabolite genes in D. septosporum showed a range of different responses to loss of DsLaeA function, thin layer chromatography revealed increased levels of a previously unknown metabolite in DsLaeA mutants. In addition, these mutants exhibited reduced asexual sporulation, germination and hydrophobicity. Our data suggest that although the developmental regulatory role of DsLaeA is conserved, its role in the regulation of secondary metabolism differs from that of LaeA in A. nidulans and appears to be species specific. This study provides a step towards understanding fundamental differences in regulation of clustered and fragmented groups of secondary metabolite genes that may shed light on understanding functional adaptation in secondary metabolism.
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Affiliation(s)
- Pranav Chettri
- Bio-Protection Research Centre, Institute of Fundamental Sciences, Massey University, Palmerston North 4474, New Zealand
| | - Rosie E Bradshaw
- Bio-Protection Research Centre, Institute of Fundamental Sciences, Massey University, Palmerston North 4474, New Zealand.
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93
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Abstract
Many Fungi have a well-developed secondary metabolism. The diversity of fungal species and the diversification of biosynthetic gene clusters underscores a nearly limitless potential for metabolic variation and an untapped resource for drug discovery and synthetic biology. Much of the ecological success of the filamentous fungi in colonizing the planet is owed to their ability to deploy their secondary metabolites in concert with their penetrative and absorptive mode of life. Fungal secondary metabolites exhibit biological activities that have been developed into life-saving medicines and agrochemicals. Toxic metabolites, known as mycotoxins, contaminate human and livestock food and indoor environments. Secondary metabolites are determinants of fungal diseases of humans, animals, and plants. Secondary metabolites exhibit a staggering variation in chemical structures and biological activities, yet their biosynthetic pathways share a number of key characteristics. The genes encoding cooperative steps of a biosynthetic pathway tend to be located contiguously on the chromosome in coregulated gene clusters. Advances in genome sequencing, computational tools, and analytical chemistry are enabling the rapid connection of gene clusters with their metabolic products. At least three fungal drug precursors, penicillin K and V, mycophenolic acid, and pleuromutilin, have been produced by synthetic reconstruction and expression of respective gene clusters in heterologous hosts. This review summarizes general aspects of fungal secondary metabolism and recent developments in our understanding of how and why fungi make secondary metabolites, how these molecules are produced, and how their biosynthetic genes are distributed across the Fungi. The breadth of fungal secondary metabolite diversity is highlighted by recent information on the biosynthesis of important fungus-derived metabolites that have contributed to human health and agriculture and that have negatively impacted crops, food distribution, and human environments.
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Affiliation(s)
- Gerald F Bills
- Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX 77054
| | - James B Gloer
- Department of Chemistry, University of Iowa, Iowa City, IA 52245
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94
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Lan H, Sun R, Fan K, Yang K, Zhang F, Nie XY, Wang X, Zhuang Z, Wang S. The Aspergillus flavus Histone Acetyltransferase AflGcnE Regulates Morphogenesis, Aflatoxin Biosynthesis, and Pathogenicity. Front Microbiol 2016; 7:1324. [PMID: 27625637 PMCID: PMC5003836 DOI: 10.3389/fmicb.2016.01324] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/11/2016] [Indexed: 12/21/2022] Open
Abstract
Histone acetyltransferases (HATs) help regulate fungal development and the production of secondary metabolites. In this study, we determined that the HAT AflGcnE influenced morphogenesis and aflatoxin biosynthesis in Aspergillus flavus. We observed that AflGcnE localized to the nucleus and cytoplasm during the conidial production and germination stages, while it was located mainly in the nucleus during the hyphal development stage. Deletion of AflgcnE inhibited the growth of A. flavus and decreased the hydrophobicity of the cell surface. The ΔAflgcnE mutant exhibited a lack of asexual sporulation and was unable to generate sclerotia. Additionally, AflgcnE was required to maintain cell wall integrity and genotoxic stress responses. Importantly, the ΔAflgcnE mutant did not produce aflatoxins, which was consistent with a significant down-regulation of aflatoxin gene expression levels. Furthermore, our data revealed that AflgcnE is a pathogenicity factor required for colonizing maize seeds. In summary, we revealed that A. flavus AflGcnE is crucial for morphological development, aflatoxin biosynthesis, stress responses, and pathogenicity. Our findings help clarify the functional divergence of GcnE orthologs, and may provide a possible target for controlling A. flavus infections of agriculturally important crops.
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Affiliation(s)
- Huahui Lan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, The Ministry of Education Key Laboratory of Biopesticide and Chemical Biology, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Ruilin Sun
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, The Ministry of Education Key Laboratory of Biopesticide and Chemical Biology, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Kun Fan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, The Ministry of Education Key Laboratory of Biopesticide and Chemical Biology, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Kunlong Yang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, The Ministry of Education Key Laboratory of Biopesticide and Chemical Biology, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Feng Zhang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, The Ministry of Education Key Laboratory of Biopesticide and Chemical Biology, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Xin Y Nie
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, The Ministry of Education Key Laboratory of Biopesticide and Chemical Biology, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Xiunai Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, The Ministry of Education Key Laboratory of Biopesticide and Chemical Biology, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Zhenhong Zhuang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, The Ministry of Education Key Laboratory of Biopesticide and Chemical Biology, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, The Ministry of Education Key Laboratory of Biopesticide and Chemical Biology, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
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95
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Chang PK, Scharfenstein LL, Ehrlich KC, Diana Di Mavungu J. The Aspergillus flavus fluP-associated metabolite promotes sclerotial production. Fungal Biol 2016; 120:1258-68. [PMID: 27647242 DOI: 10.1016/j.funbio.2016.07.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 07/22/2016] [Accepted: 07/25/2016] [Indexed: 12/22/2022]
Abstract
Aspergillus flavus is able to synthesize a variety of polyketide-derived secondary metabolites including the hepatocarcinogen, aflatoxin B1. The fungus reproduces and disseminates predominantly by production of conidia. It also produces hardened mycelial aggregates called sclerotia that are used to cope with unfavourable growth environments. In the present study, we examined the role of A. flavus fluP, the backbone polyketide synthase gene of secondary metabolite gene cluster 41, on fungal development. The A. flavus CA14 fluP deletion mutant (AfΔfluP) grew and accumulated aflatoxin normally but produced a lower amount of sclerotia than the parental strain. This was also true for the Aspergillus parasiticus BN9 fluP deletion mutant (ApΔfluP). The A. flavus fluP gene was positively regulated by developmental regulators of VeA and VelB but not by the global regulator of secondary metabolism, LaeA. Overexpression of fluP in AfΔfluP (OEfluP) elevated its ability to produce sclerotia compared to that of the parental strain. Coculture of OEfluP with CA14, AfΔfluP, ApΔfluP, or an A. flavus pptA deletion mutant incapable of producing functional polyketide synthases also allowed increased sclerotial production of the respective strains at edges where colonies made contact. Acetone extracts of OEfluP but not of AfΔfluP exhibited the same effect in promoting sclerotial production of AfΔfluP. These results suggest that FluP polyketide synthase is involved in the synthesis of a diffusible metabolite that could serve as a signal molecule to regulate sclerotiogenesis.
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Affiliation(s)
- Perng-Kuang Chang
- Southern Regional Research Center, Agricultural Research Service, U. S. Department of Agriculture, 1100 Robert E. Lee Boulevard, New Orleans, LA 70124, United States.
| | - Leslie L Scharfenstein
- Southern Regional Research Center, Agricultural Research Service, U. S. Department of Agriculture, 1100 Robert E. Lee Boulevard, New Orleans, LA 70124, United States
| | - Kenneth C Ehrlich
- Southern Regional Research Center, Agricultural Research Service, U. S. Department of Agriculture, 1100 Robert E. Lee Boulevard, New Orleans, LA 70124, United States
| | - José Diana Di Mavungu
- Laboratory of Food Analysis, Faculty of Pharmaceutical Sciences, Ghent University, 460 Ottergemsesteenweg, 9000 Ghent, Belgium
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96
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Satterlee T, Cary JW, Calvo AM. RmtA, a Putative Arginine Methyltransferase, Regulates Secondary Metabolism and Development in Aspergillus flavus. PLoS One 2016; 11:e0155575. [PMID: 27213959 PMCID: PMC4877107 DOI: 10.1371/journal.pone.0155575] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 05/01/2016] [Indexed: 12/31/2022] Open
Abstract
Aspergillus flavus colonizes numerous oil seed crops such as corn, peanuts, treenuts and cotton worldwide, contaminating them with aflatoxin and other harmful potent toxins. In the phylogenetically related model fungus Aspergillus nidulans, the methyltransferase, RmtA, has been described to be involved in epigenetics regulation through histone modification. Epigenetics regulation affects a variety of cellular processes, including morphogenesis and secondary metabolism. Our study shows that deletion of rmtA in A. flavus results in hyperconidiating colonies, indicating that rmtA is a repressor of asexual development in this fungus. The increase in conidiation in the absence of rmtA coincides with greater expression of brlA, abaA, and wetA compared to that in the wild type. Additionally, the rmtA deletion mutant presents a drastic reduction or loss of sclerotial production, while forced expression of this gene increased the ability of this fungus to generate these resistant structures, revealing rmtA as a positive regulator of sclerotial formation. Importantly, rmtA is also required for the production of aflatoxin B1 in A. flavus, affecting the expression of aflJ. Furthermore, biosynthesis of additional metabolites is also controlled by rmtA, indicating a broad regulatory output in the control of secondary metabolism. This study also revealed that rmtA positively regulates the expression of the global regulatory gene veA, which could contribute to mediate the effects of rmtA on development and secondary metabolism in this relevant opportunistic plant pathogen.
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Affiliation(s)
- Timothy Satterlee
- Department of Biological Sciences, Northern Illinois University, Dekalb, IL, 60115, United States of America
| | - Jeffrey W. Cary
- USDA, ARS, Southern Regional Research Center, New Orleans, LA, 70124, United States of America
| | - Ana M. Calvo
- Department of Biological Sciences, Northern Illinois University, Dekalb, IL, 60115, United States of America
- * E-mail:
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Holighaus G, Rohlfs M. Fungal allelochemicals in insect pest management. Appl Microbiol Biotechnol 2016; 100:5681-9. [PMID: 27147531 DOI: 10.1007/s00253-016-7573-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/16/2016] [Accepted: 04/19/2016] [Indexed: 12/31/2022]
Abstract
Interactions between insects and fungi are widespread, and important mediators of these interactions are fungal chemicals that can therefore be considered as allelochemicals. Numerous studies suggest that fungal chemicals can affect insects in many different ways. Here, we apply the terminology established by insect-plant ecologists for categorizing the effect of fungal allelochemicals on insects and for evaluating the application potential of these chemicals in insect pest management. Our literature survey shows that fungal volatile and non-volatile chemicals have an enormous potential to influence insect behavior and fitness. Many of them still remain to be discovered, but some recent examples of repellents and toxins could open up new ways for developing safe insect control strategies. However, we also identified shortcomings in our understanding of the chemical ecology of insect-fungus interactions and the way they have been investigated. In particular, the mode-of-action of fungal allelochemicals has often not been appropriately designated or examined, and the way in which induction by insects affects fungal chemical diversity is poorly understood. This review should raise awareness that in-depth ecological studies of insect-fungus interactions can reveal novel allelochemicals of particular benefit for the development of innovative insect pest management strategies.
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Affiliation(s)
- Gerrit Holighaus
- J.F. Blumenbach Institute of Zoology and Anthropology, Georg-August-University of Göttingen, Göttingen, Germany
- Büsgen Institute, Forest Zoology and Forest Conservation, Georg-August-University of Göttingen, Göttingen, Germany
| | - Marko Rohlfs
- J.F. Blumenbach Institute of Zoology and Anthropology, Georg-August-University of Göttingen, Göttingen, Germany.
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Rauscher S, Pacher S, Hedtke M, Kniemeyer O, Fischer R. A phosphorylation code of theAspergillus nidulansglobal regulator VelvetA (VeA) determines specific functions. Mol Microbiol 2015; 99:909-24. [DOI: 10.1111/mmi.13275] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Stefan Rauscher
- Institute for Applied Biosciences; Department of Microbiology; Karlsruhe Institute of Technology; Hertzstrasse 16 D-76187 Karlsruhe Germany
| | - Sylvia Pacher
- Institute for Applied Biosciences; Department of Microbiology; Karlsruhe Institute of Technology; Hertzstrasse 16 D-76187 Karlsruhe Germany
| | - Maren Hedtke
- Institute for Applied Biosciences; Department of Microbiology; Karlsruhe Institute of Technology; Hertzstrasse 16 D-76187 Karlsruhe Germany
| | - Olaf Kniemeyer
- Leibniz Institute for Natural Product Research and Infection Biology; Hans-Knöll-Institute (HKI); Adolf-Reichwein-Str. 23 07745 Jena Germany
| | - Reinhard Fischer
- Institute for Applied Biosciences; Department of Microbiology; Karlsruhe Institute of Technology; Hertzstrasse 16 D-76187 Karlsruhe Germany
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Transcriptome Analysis of Aspergillus flavus Reveals veA-Dependent Regulation of Secondary Metabolite Gene Clusters, Including the Novel Aflavarin Cluster. EUKARYOTIC CELL 2015. [PMID: 26209694 DOI: 10.1128/ec.00092-15] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The global regulatory veA gene governs development and secondary metabolism in numerous fungal species, including Aspergillus flavus. This is especially relevant since A. flavus infects crops of agricultural importance worldwide, contaminating them with potent mycotoxins. The most well-known are aflatoxins, which are cytotoxic and carcinogenic polyketide compounds. The production of aflatoxins and the expression of genes implicated in the production of these mycotoxins are veA dependent. The genes responsible for the synthesis of aflatoxins are clustered, a signature common for genes involved in fungal secondary metabolism. Studies of the A. flavus genome revealed many gene clusters possibly connected to the synthesis of secondary metabolites. Many of these metabolites are still unknown, or the association between a known metabolite and a particular gene cluster has not yet been established. In the present transcriptome study, we show that veA is necessary for the expression of a large number of genes. Twenty-eight out of the predicted 56 secondary metabolite gene clusters include at least one gene that is differentially expressed depending on presence or absence of veA. One of the clusters under the influence of veA is cluster 39. The absence of veA results in a downregulation of the five genes found within this cluster. Interestingly, our results indicate that the cluster is expressed mainly in sclerotia. Chemical analysis of sclerotial extracts revealed that cluster 39 is responsible for the production of aflavarin.
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