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Liang L, Wang X, Wei S, Lei Y, Zhang S, Zhai H, Hu Y, Lv Y. m 6A methyltransferase AflIme4 orchestrates mycelial growth, development and aflatoxin B 1 biosynthesis in Aspergillus flavus. Microbiol Res 2024; 283:127710. [PMID: 38593581 DOI: 10.1016/j.micres.2024.127710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/20/2024] [Accepted: 03/30/2024] [Indexed: 04/11/2024]
Abstract
Aflatoxin B1 (AFB1), a highly toxic secondary metabolite produced by Aspergillus flavus, poses a severe threat to agricultural production, food safety and human health. The methylation of mRNA m6A has been identified as a regulator of both the growth and AFB1 production of A. flavus. However, its intracellular occurrence and function needs to be elucidated. Here, we identified and characterized a m6A methyltransferase, AflIme4, in A. flavus. The enzyme was localized in the cytoplasm, and knockout of AflIme4 significantly reduced the methylation modification level of mRNA. Compared with the control strains, ΔAflIme4 exhibited diminished growth, conidial formation, mycelial hydrophobicity, sclerotium yield, pathogenicity and increased sensitivity to CR, SDS, NaCl and H2O2. Notably, AFB1 production was markedly inhibited in the A. flavus ΔAflIme4 strain. RNA-Seq coupled with RT-qPCR validation showed that the transcriptional levels of genes involved in the AFB1 biosynthesis pathway including aflA, aflG, aflH, aflK, aflL, aflO, aflS, aflV and aflY were significantly upregulated. Methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR) analysis demonstrated a significant increase in m6A methylation modification levels of these pathway-specific genes, concomitant with a decrease in mRNA stability. These results suggest that AflIme4 attenuates the mRNA stability of genes in AFB1 biosynthesis by enhancing their mRNA m6A methylation modification, leading to impaired AFB1 biosynthesis. Our study identifies a novel m6A methyltransferase AflIme4 and highlights it as a potential target to control A. flavus growth, development and aflatoxin pollution.
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Affiliation(s)
- Liuke Liang
- College of biological engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Xiaoyan Wang
- College of biological engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Shan Wei
- College of biological engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Yang Lei
- College of biological engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Shuaibing Zhang
- College of biological engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Huanchen Zhai
- College of biological engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Yuansen Hu
- College of biological engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Yangyong Lv
- College of biological engineering, Henan University of Technology, Zhengzhou 450001, China.
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2
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Speckbacher V, Flatschacher D, Martini-Lösch N, Ulbrich L, Baldin C, Bauer I, Ruzsanyi V, Zeilinger S. The histone deacetylase Hda1 affects oxidative and osmotic stress response as well as mycoparasitic activity and secondary metabolite biosynthesis in Trichoderma atroviride. Microbiol Spectr 2024; 12:e0309723. [PMID: 38334386 PMCID: PMC10913545 DOI: 10.1128/spectrum.03097-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 01/10/2024] [Indexed: 02/10/2024] Open
Abstract
The mycoparasitic fungus Trichoderma atroviride is applied in agriculture as a biostimulant and biologic control agent against fungal pathogens that infest crop plants. Secondary metabolites are among the main agents determining the strength and progress of the mycoparasitic attack. However, expression of most secondary metabolism-associated genes requires specific cues, as they are silent under routine laboratory conditions due to their maintenance in an inactive heterochromatin state. Therefore, histone modifications are crucial for the regulation of secondary metabolism. Here, we functionally investigated the role of the class II histone deacetylase encoding gene hda1 of T. atroviride by targeted gene deletion, phenotypic characterization, and multi-omics approaches. Deletion of hda1 did not result in obvious phenotypic alterations but led to an enhanced inhibitory activity of secreted metabolites and reduced mycoparasitic abilities of T. atroviride against the plant-pathogenic fungi Botrytis cinerea and Rhizoctonia solani. The ∆hda1 mutants emitted altered amounts of four volatile organic compounds along their development, produced different metabolite profiles upon growth in liquid culture, and showed a higher susceptibility to oxidative and osmotic stress. Moreover, hda1 deletion affected the expression of several notable gene categories such as polyketide synthases, transcription factors, and genes involved in the HOG MAPK pathway.IMPORTANCEHistone deacetylases play crucial roles in regulating chromatin structure and gene transcription. To date, classical-Zn2+ dependent-fungal histone deacetylases are divided into two classes, of which each comprises orthologues of the two sub-groups Rpd3 and Hos2 and Hda1 and Hos3 of yeast, respectively. However, the role of these chromatin remodelers in mycoparasitic fungi is poorly understood. In this study, we provide evidence that Hda1, the class II histone deacetylases of the mycoparasitic fungus Trichoderma atroviride, regulates its mycoparasitic activity, secondary metabolite biosynthesis, and osmotic and oxidative stress tolerance. The function of Hda1 in regulating bioactive metabolite production and mycoparasitism reveals the importance of chromatin-dependent regulation in the ability of T. atroviride to successfully control fungal plant pathogens.
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Affiliation(s)
| | | | | | - Laura Ulbrich
- Umweltmonitoring und Forensische Chemie, Hochschule Hamm-Lippstadt, Hamm, Germany
| | - Clara Baldin
- Department of Microbiology, Universität Innsbruck, Innsbruck, Austria
| | - Ingo Bauer
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Susanne Zeilinger
- Department of Microbiology, Universität Innsbruck, Innsbruck, Austria
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Wang B, Duan G, Liu L, Long Z, Bai X, Ou M, Wang P, Jiang D, Li D, Sun W. UvHOS3-mediated histone deacetylation is essential for virulence and negatively regulates ustilaginoidin biosynthesis in Ustilaginoidea virens. MOLECULAR PLANT PATHOLOGY 2024; 25:e13429. [PMID: 38353606 PMCID: PMC10866089 DOI: 10.1111/mpp.13429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 01/18/2024] [Accepted: 01/18/2024] [Indexed: 02/16/2024]
Abstract
Ustilaginoidea virens is the causal agent of rice false smut, which has recently become one of the most important rice diseases worldwide. Ustilaginoidins, a major type of mycotoxins produced in false smut balls, greatly deteriorates grain quality. Histone acetylation and deacetylation are involved in regulating secondary metabolism in fungi. However, little is yet known on the functions of histone deacetylases (HDACs) in virulence and mycotoxin biosynthesis in U. virens. Here, we characterized the functions of the HDAC UvHOS3 in U. virens. The ΔUvhos3 deletion mutant exhibited the phenotypes of retarded growth, increased mycelial branches and reduced conidiation and virulence. The ΔUvhos3 mutants were more sensitive to sorbitol, sodium dodecyl sulphate and oxidative stress/H2 O2 . ΔUvhos3 generated significantly more ustilaginoidins. RNA-Seq and metabolomics analyses also revealed that UvHOS3 is a key negative player in regulating secondary metabolism, especially mycotoxin biosynthesis. Notably, UvHOS3 mediates deacetylation of H3 and H4 at H3K9, H3K18, H3K27 and H4K8 residues. Chromatin immunoprecipitation assays indicated that UvHOS3 regulates mycotoxin biosynthesis, particularly for ustilaginoidin and sorbicillinoid production, by modulating the acetylation level of H3K18. Collectively, this study deepens the understanding of molecular mechanisms of the HDAC UvHOS3 in regulating virulence and mycotoxin biosynthesis in phytopathogenic fungi.
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Affiliation(s)
- Bo Wang
- College of Plant Protection and the Ministry of Agriculture Key Laboratory of Pest Monitoring and Green ManagementChina Agricultural UniversityBeijingChina
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
- College of Plant ProtectionSanya Institute of China Agricultural UniversitySanyaChina
| | - Guohua Duan
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Ling Liu
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Zhaoyi Long
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Xiaolong Bai
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Mingming Ou
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Peiying Wang
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Du Jiang
- College of Plant Protection and the Ministry of Agriculture Key Laboratory of Pest Monitoring and Green ManagementChina Agricultural UniversityBeijingChina
- College of Plant ProtectionSanya Institute of China Agricultural UniversitySanyaChina
| | - Dayong Li
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Wenxian Sun
- College of Plant Protection and the Ministry of Agriculture Key Laboratory of Pest Monitoring and Green ManagementChina Agricultural UniversityBeijingChina
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
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4
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Liu Q, Zheng Y, Liu B, Tang F, Shao Y. Histone deacetylase MrHos3 negatively regulates the production of citrinin and pigments in Monascus ruber. J Basic Microbiol 2023; 63:1128-1138. [PMID: 37236161 DOI: 10.1002/jobm.202300138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/25/2023] [Accepted: 05/06/2023] [Indexed: 05/28/2023]
Abstract
Monascus spp. can produce a variety of beneficial metabolites widely used in food and pharmaceutical industries. However, some Monascus species contain the complete gene cluster responsible for citrinin biosynthesis, which raises our concerns about the safety of their fermented products. In this study, the gene Mrhos3, encoding histone deacetylase (HDAC), was deleted to evaluate its effects on the production of mycotoxin (citrinin) and the edible pigments as well as the developmental process of Monascus ruber M7. The results showed that absence of Mrhos3 caused an enhancement of citrinin content by 105.1%, 82.4%, 111.9%, and 95.7% at the 5th, 7th, 9th, and 11th day, respectively. Furthermore, deletion of Mrhos3 increased the relative expression of citrinin biosynthetic pathway genes including pksCT, mrl1, mrl2, mrl4, mrl6, and mrl7. In addition, deletion of Mrhos3 led to an increase in total pigment content and six classic pigment components. Western blot results revealed that deletion of Mrhos3 could significantly elevate the acetylation level of H3K9, H4K12, H3K18, and total protein. This study provides an important insight into the effects of hos3 gene on the secondary metabolites production in filamentous fungi.
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Affiliation(s)
- Qianrui Liu
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yunfan Zheng
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Baixue Liu
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Fufang Tang
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yanchun Shao
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, China
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Liu L, Wang B, Duan G, Wang J, Pan Z, Ou M, Bai X, Wang P, Zhao D, Nan N, Li D, Sun W. Histone Deacetylase UvHST2 Is a Global Regulator of Secondary Metabolism in Ustilaginoidea virens. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:13124-13136. [PMID: 37615365 DOI: 10.1021/acs.jafc.3c01782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
Ustilaginoidea virens, the causal agent of rice false smut, produces a large amount of mycotoxins, including ustilaginoidins and sorbicillinoids. However, little is known about the regulatory mechanism of mycotoxin biosynthesis inU. virens. Here, we demonstrate that the NAD+-dependent histone deacetylase UvHST2 negatively regulates ustilaginoidin biosynthesis. UvHst2 knockout caused retarded hypha growth and reduced conidiation and pathogenicity inU. virens. Transcriptome analysis revealed that the transcription factor genes, transporter genes, and other tailoring genes in eight biosynthetic gene clusters (BGCs) including ustilaginoidin and sorbicillinoid BGCs were upregulated in ΔUvhst2. Interestingly, the UvHst2 deletion affects alternative splicing. Metabolomics revealed that UvHST2 negatively regulates the biosynthesis of various mycotoxins including ustilaginoidins, sorbicillin, ochratoxin B, zearalenone, and O-M-sterigmatocystin. Combined transcriptome and metabolome analyses uncover that UvHST2 positively regulates pathogenicity but negatively modulates the expression of BGCs involved in secondary metabolism. Collectively, UvHST2 functions as a global regulator of secondary metabolism inU. virens.
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Affiliation(s)
- Ling Liu
- College of Plant Protection, Jilin Provincial Key Laboratory of Green Management of Crop Pests and Diseases, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, Jilin, China
| | - Bo Wang
- College of Plant Protection, Jilin Provincial Key Laboratory of Green Management of Crop Pests and Diseases, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, Jilin, China
- College of Plant Protection and the Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management, China Agricultural University, Beijing 100193, China
| | - Guohua Duan
- College of Plant Protection, Jilin Provincial Key Laboratory of Green Management of Crop Pests and Diseases, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, Jilin, China
| | - Jing Wang
- College of Plant Protection, Jilin Provincial Key Laboratory of Green Management of Crop Pests and Diseases, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, Jilin, China
| | - Zequn Pan
- College of Plant Protection, Jilin Provincial Key Laboratory of Green Management of Crop Pests and Diseases, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, Jilin, China
| | - Mingming Ou
- College of Plant Protection, Jilin Provincial Key Laboratory of Green Management of Crop Pests and Diseases, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, Jilin, China
| | - Xiaolong Bai
- College of Plant Protection, Jilin Provincial Key Laboratory of Green Management of Crop Pests and Diseases, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, Jilin, China
| | - Peiying Wang
- College of Plant Protection, Jilin Provincial Key Laboratory of Green Management of Crop Pests and Diseases, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, Jilin, China
| | - Dan Zhao
- College of Plant Protection, Jilin Provincial Key Laboratory of Green Management of Crop Pests and Diseases, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, Jilin, China
| | - Nan Nan
- College of Plant Protection, Jilin Provincial Key Laboratory of Green Management of Crop Pests and Diseases, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, Jilin, China
| | - Dayong Li
- College of Plant Protection, Jilin Provincial Key Laboratory of Green Management of Crop Pests and Diseases, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, Jilin, China
| | - Wenxian Sun
- College of Plant Protection, Jilin Provincial Key Laboratory of Green Management of Crop Pests and Diseases, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, Jilin, China
- College of Plant Protection and the Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management, China Agricultural University, Beijing 100193, China
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6
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Ferrara M, Perrone G, Gallo A. Recent advances in biosynthesis and regulatory mechanisms of principal mycotoxins. Curr Opin Food Sci 2022. [DOI: 10.1016/j.cofs.2022.100923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Glutamine Synthetase Contributes to the Regulation of Growth, Conidiation, Sclerotia Development, and Resistance to Oxidative Stress in the Fungus Aspergillus flavus. Toxins (Basel) 2022; 14:toxins14120822. [PMID: 36548719 PMCID: PMC9785230 DOI: 10.3390/toxins14120822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/12/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022] Open
Abstract
The basic biological function of glutamine synthetase (Gs) is to catalyze the conversion of ammonium and glutamate to glutamine. This synthetase also performs other biological functions. However, the roles of Gs in fungi, especially in filamentous fungi, are not fully understood. Here, we found that conditional disruption of glutamine synthetase (AflGsA) gene expression in Aspergillus flavus by using a xylose promoter leads to a complete glutamine deficiency. Supplementation of glutamine could restore the nutritional deficiency caused by AflGsA expression deficiency. Additionally, by using the xylose promoter for the downregulation of AflgsA expression, we found that AflGsA regulates spore and sclerotic development by regulating the transcriptional levels of sporulation genes abaA and brlA and the sclerotic generation genes nsdC and nsdD, respectively. In addition, AflGsA was found to maintain the balance of reactive oxygen species (ROS) and to aid in resisting oxidative stress. AflGsA is also involved in the regulation of light signals through the production of glutamine. The results also showed that the recombinant AflGsA had glutamine synthetase activity in vitro and required the assistance of metal ions. The inhibitor molecule L-α-aminoadipic acid suppressed the activity of rAflGsA in vitro and disrupted the morphogenesis of spores, sclerotia, and colonies in A. flavus. These results provide a mechanistic link between nutrition metabolism and glutamine synthetase in A. flavus and suggest a strategy for the prevention of fungal infection.
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Wen M, Lan H, Sun R, Chen X, Zhang X, Zhu Z, Tan C, Yuan J, Wang S. Histone deacetylase SirE regulates development, DNA damage response and aflatoxin production in Aspergillus flavus. Environ Microbiol 2022; 24:5596-5610. [PMID: 36059183 DOI: 10.1111/1462-2920.16198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 08/24/2022] [Indexed: 11/28/2022]
Abstract
Aspergillus flavus is a ubiquitous saprotrophic soil-borne pathogenic fungus that causes crops contamination with the carcinogen aflatoxins. Although Sirtuin E (SirE) is known to be a NAD-dependent histone deacetylase involved in global transcriptional regulation. Its biological functions in A. flavus are not fully understood. To explore the effects of SirE, we found that SirE was located in the nucleus and increased the level of H3K56 acetylation. The ΔsirE mutant had the most severe growth defect in the sirtuin family. The RNA-Seq revealed that sirE was crucial for secondary metabolism production as well as genetic information process and oxidation-reduction in A. flavus. Further analysis revealed that the ΔsirE mutant increased aflatoxin production. Both the sirE deletion and H3K56 mutants were highly sensitive to DNA damage and oxidative stresses, indicating that SirE was required for DNA damage and redox reaction by the H3K56 locus. Furthermore, the ΔsirE mutant displayed high sensitivity to osmotic stress and cell wall stress, but they may not be associated with the H3K56. Finally, the catalytic activity site N192 of SirE was required for regulating growth, deacetylase function and aflatoxin production. Together, SirE is essential for histone deacetylation and biological function in A. flavus.
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Affiliation(s)
- Meifang Wen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Huahui Lan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ruilin Sun
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xuan Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xin Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhuo Zhu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Can Tan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jun Yuan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shihua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
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Schüller A, Studt-Reinhold L, Strauss J. How to Completely Squeeze a Fungus-Advanced Genome Mining Tools for Novel Bioactive Substances. Pharmaceutics 2022; 14:1837. [PMID: 36145585 PMCID: PMC9505985 DOI: 10.3390/pharmaceutics14091837] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/23/2022] [Accepted: 08/29/2022] [Indexed: 11/17/2022] Open
Abstract
Fungal species have the capability of producing an overwhelming diversity of bioactive substances that can have beneficial but also detrimental effects on human health. These so-called secondary metabolites naturally serve as antimicrobial "weapon systems", signaling molecules or developmental effectors for fungi and hence are produced only under very specific environmental conditions or stages in their life cycle. However, as these complex conditions are difficult or even impossible to mimic in laboratory settings, only a small fraction of the true chemical diversity of fungi is known so far. This also implies that a large space for potentially new pharmaceuticals remains unexplored. We here present an overview on current developments in advanced methods that can be used to explore this chemical space. We focus on genetic and genomic methods, how to detect genes that harbor the blueprints for the production of these compounds (i.e., biosynthetic gene clusters, BGCs), and ways to activate these silent chromosomal regions. We provide an in-depth view of the chromatin-level regulation of BGCs and of the potential to use the CRISPR/Cas technology as an activation tool.
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Affiliation(s)
| | | | - Joseph Strauss
- Institute of Microbial Genetics, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences Vienna, A-3430 Tulln/Donau, Austria
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Qin L, Yang L, Zhao J, Zeng W, Su M, Wang S, Yuan J. GTPase Rac Regulates Conidiation, AFB1 Production and Stress Response in Pathogenic Fungus Aspergillus flavus. Toxins (Basel) 2022; 14:toxins14090581. [PMID: 36136519 PMCID: PMC9503438 DOI: 10.3390/toxins14090581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/14/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
As a member of the Rho family, Rac plays important roles in many species, including proliferation, differentiation, apoptosis, DNA damage responses, metabolism, angiogenesis, and immunosuppression. In this study, by constructing Rac-deleted mutants in Aspergillus flavus, it was found that the deletion of Rac gene led to the decline of growth and development, conidia production, AFB1 toxin synthesis, and seed infection ability of A. flavus. The deletion of Rac gene also caused the disappearance of A. flavus sclerotium, indicating that Rac is required for sclerotium formation in A. flavus. The sensitivity of Rac-deficient strains responding to cell wall stress and osmotic pressure stress increased when compared to A.flavus WT. The Western blot result showed that mitogen-activated serine/threonine-protein kinase Slt2 and mitogen-activated protein kinase Hog1 proteins were no longer phosphorylated in Rac-deficient strains of A. flavus, showing that Rac may be used as a molecular switch to control the Slt2-MAPK cascade pathway and regulate the osmotic Hog-MAPK cascade pathway in A. flavus in response to external stress. Altogether, these results indicated that Rac was involved in regulating the growth and development, conidia formation and AFB1 synthesis, and response to cell wall stress and osmotic pressure stress in A. flavus.
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11
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Li Y, Song Z, Wang E, Dong L, Bai J, Wang D, Zhu J, Zhang C. Potential antifungal targets based on histones post-translational modifications against invasive aspergillosis. Front Microbiol 2022; 13:980615. [PMID: 36016791 PMCID: PMC9395700 DOI: 10.3389/fmicb.2022.980615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 07/27/2022] [Indexed: 11/17/2022] Open
Abstract
As a primary cause of death in patients with hematological malignancies and transplant recipients, invasive aspergillosis (IA) is a condition that warrants attention. IA infections have been increasing, which remains a significant cause of morbidity and mortality in immunocompromised patients. During the past decade, antifungal drug resistance has emerged, which is especially concerning for management given the limited options for treating azole-resistant infections and the possibility of failure of prophylaxis in those high-risk patients. Histone posttranslational modifications (HPTMs), mainly including acetylation, methylation, ubiquitination and phosphorylation, are crucial epigenetic mechanisms regulating various biological events, which could modify the conformation of histone and influence chromatin-associated nuclear processes to regulate development, cellular responsiveness, and biological phenotype without affecting the underlying genetic sequence. In recent years, fungi have become important model organisms for studying epigenetic regulation. HPTMs involves in growth and development, secondary metabolite biosynthesis and virulence in Aspergillus. This review mainly aims at summarizing the acetylation, deacetylation, methylation, demethylation, and sumoylation of histones in IA and connect this knowledge to possible HPTMs-based antifungal drugs. We hope this research could provide a reference for exploring new drug targets and developing low-toxic and high-efficiency antifungal strategies.
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Affiliation(s)
- Yiman Li
- Department of Pharmacy, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Zhihui Song
- Department of Pharmacy, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Ente Wang
- Department of Pharmacy, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Liming Dong
- Department of Pharmacy, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Jie Bai
- Department of Pharmacy, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Dong Wang
- Department of Pharmacy, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Jinyan Zhu
- Department of Hematology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Chao Zhang
- Department of Pharmacy, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- *Correspondence: Chao Zhang,
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12
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Yang K, Tian J, Keller NP. Post-translational modifications drive secondary metabolite biosynthesis in Aspergillus: a review. Environ Microbiol 2022; 24:2857-2881. [PMID: 35645150 PMCID: PMC9545273 DOI: 10.1111/1462-2920.16034] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 04/23/2022] [Accepted: 04/26/2022] [Indexed: 12/26/2022]
Abstract
Post‐translational modifications (PTMs) are important for protein function and regulate multiple cellular processes and secondary metabolites (SMs) in fungi. Aspergillus species belong to a genus renown for an abundance of bioactive secondary metabolites, many important as toxins, pharmaceuticals and in industrial production. The genes required for secondary metabolites are typically co‐localized in biosynthetic gene clusters (BGCs), which often localize in heterochromatic regions of genome and are ‘turned off’ under laboratory condition. Efforts have been made to ‘turn on’ these BGCs by genetic manipulation of histone modifications, which could convert the heterochromatic structure to euchromatin. Additionally, non‐histone PTMs also play critical roles in the regulation of secondary metabolism. In this review, we collate the known roles of epigenetic and PTMs on Aspergillus SM production. We also summarize the proteomics approaches and bioinformatics tools for PTM identification and prediction and provide future perspectives on the emerging roles of PTM on regulation of SM biosynthesis in Aspergillus and other fungi.
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Affiliation(s)
- Kunlong Yang
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, People's Republic of China.,Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, 53705, USA
| | - Jun Tian
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, People's Republic of China
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, 53705, USA
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Combination Strategy of Genetic Dereplication and Manipulation of Epigenetic Regulators Reveals a Novel Compound from Plant Endophytic Fungus. Int J Mol Sci 2022; 23:ijms23073686. [PMID: 35409046 PMCID: PMC8998291 DOI: 10.3390/ijms23073686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/24/2022] [Accepted: 03/25/2022] [Indexed: 12/10/2022] Open
Abstract
The strategies of genetic dereplication and manipulation of epigenetic regulators to activate the cryptic gene clusters are effective to discover natural products with novel structure in filamentous fungi. In this study, a combination of genetic dereplication (deletion of pesthetic acid biosynthetic gene, PfptaA) and manipulation of epigenetic regulators (deletion of histone methyltransferase gene PfcclA and histone deacetylase gene PfhdaA) was developed in plant endophytic fungus Pestalotiopsis fici. The deletion of PfptaA with PfcclA and/or PfhdaA led to isolation of 1 novel compound, pestaloficiol X (1), as well as another 11 known compounds with obvious yield changes. The proposed biosynthesis pathway of pestaloficiol X was speculated using comparative analysis of homologous biosynthetic gene clusters. Moreover, phenotypic effects on the conidial development and response to oxidative stressors in the mutants were explored. Our results revealed that the new strain with deletion of PfcclA or PfhdaA in ΔPfptaA background host can neutralise the hyperformation of conidia in the PfptaA mutant, and that the ΔPfptaA ΔPfhdaA mutant was generally not sensitive to oxidative stressors as much as the ΔPfptaA ΔcclA mutant in comparison with the single mutant ΔPfptaA or the parental strains. This combinatorial approach can be applied to discover new natural products in filamentous fungi.
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Chen X, Wu L, Lan H, Sun R, Wen M, Ruan D, Zhang M, Wang S. Histone acetyltransferases MystA and MystB contribute to morphogenesis and aflatoxin biosynthesis by regulating acetylation in fungus Aspergillus flavus. Environ Microbiol 2021; 24:1340-1361. [PMID: 34863014 DOI: 10.1111/1462-2920.15856] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 11/19/2021] [Indexed: 11/28/2022]
Abstract
Myst family is highly conserved histone acetyltransferases in eukaryotic cells and is known to play crucial roles in various cellular processes; however, acetylation catalysed by acetyltransferases is unclear in filamentous fungi. Here, we identified two classical nonessential Myst enzymes and analysed their functions in Aspergillus flavus, which generates aflatoxin B1, one of the most carcinogenic secondary metabolites. MystA and MystB located in nuclei and cytoplasm, and mystA could acetylate H4K16ac, while mystB acetylates H3K14ac, H3K18ac and H3K23ac. Deletion mystA resulted in decreased conidiation, increased sclerotia formation and aflatoxin production. Deletion of mystB leads to significant defects in conidiation, sclerotia formation and aflatoxin production. Additionally, double-knockout mutant (ΔmystA/mystB) display a stronger and similar defect to ΔmystB mutant, indicating that mystB plays a major role in regulating development and aflatoxin production. Both mystA and mystB play important role in crop colonization. Moreover, catalytic domain MOZ and the catalytic site E199/E243 were important for the acetyltransferase function of Myst. Notably, chromatin immunoprecipitation results indicated that mystB participated in oxidative detoxification by regulating the acetylation level of H3K14, and further regulated nsdD to affect sclerotia formation and aflatoxin production. This study provides new evidences to discover the biological functions of histone acetyltransferase in A. flavus.
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Affiliation(s)
- Xuan Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Lianghuan Wu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Huahui Lan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Ruilin Sun
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Meifang Wen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Danrui Ruan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Mengjuan Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Shihua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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15
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Fungal Lysine Deacetylases in Virulence, Resistance, and Production of Small Bioactive Compounds. Genes (Basel) 2021; 12:genes12101470. [PMID: 34680865 PMCID: PMC8535771 DOI: 10.3390/genes12101470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 09/20/2021] [Indexed: 12/13/2022] Open
Abstract
The growing number of immunocompromised patients begs for efficient therapy strategies against invasive fungal infections. As conventional antifungal treatment is increasingly hampered by resistance to commonly used antifungals, development of novel therapy regimens is required. On the other hand, numerous fungal species are industrially exploited as cell factories of enzymes and chemicals or as producers of medically relevant pharmaceuticals. Consequently, there is immense interest in tapping the almost inexhaustible fungal portfolio of natural products for potential medical and industrial applications. Both the pathogenicity and production of those small metabolites are significantly dependent on the acetylation status of distinct regulatory proteins. Thus, classical lysine deacetylases (KDACs) are crucial virulence determinants and important regulators of natural products of fungi. In this review, we present an overview of the members of classical KDACs and their complexes in filamentous fungi. Further, we discuss the impact of the genetic manipulation of KDACs on the pathogenicity and production of bioactive molecules. Special consideration is given to inhibitors of these enzymes and their role as potential new antifungals and emerging tools for the discovery of novel pharmaceutical drugs and antibiotics in fungal producer strains.
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Updates on the Functions and Molecular Mechanisms of the Genes Involved in Aspergillus flavus Development and Biosynthesis of Aflatoxins. J Fungi (Basel) 2021; 7:jof7080666. [PMID: 34436205 PMCID: PMC8401812 DOI: 10.3390/jof7080666] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 08/08/2021] [Accepted: 08/10/2021] [Indexed: 12/13/2022] Open
Abstract
Aspergillus flavus (A. flavus) is a ubiquitous and opportunistic fungal pathogen that causes invasive and non-invasive aspergillosis in humans and animals. This fungus is also capable of infecting a large number of agriculture crops (e.g., peanuts, maze, cotton seeds, rice, etc.), causing economic losses and posing serious food-safety concerns when these crops are contaminated with aflatoxins, the most potent naturally occurring carcinogens. In particular, A. flavus and aflatoxins are intensely studied, and they continue to receive considerable attention due to their detrimental effects on humans, animals, and crops. Although several studies have been published focusing on the biosynthesis of the aforementioned secondary metabolites, some of the molecular mechanisms (e.g., posttranslational modifications, transcription factors, transcriptome, proteomics, metabolomics and transcriptome, etc.) involved in the fungal development and aflatoxin biosynthesis in A. flavus are still not fully understood. In this study, a review of the recently published studies on the function of the genes and the molecular mechanisms involved in development of A. flavus and the production of its secondary metabolites is presented. It is hoped that the information provided in this review will help readers to develop effective strategies to reduce A. flavus infection and aflatoxin production.
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Zhu H, Wang C. HDAC2-mediated proliferation of trophoblast cells requires the miR-183/FOXA1/IL-8 signaling pathway. J Cell Physiol 2021; 236:2544-2558. [PMID: 33164209 DOI: 10.1002/jcp.30026] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 07/24/2020] [Accepted: 07/28/2020] [Indexed: 12/14/2022]
Abstract
Pre-eclampsia (PE) is a major cause of maternal and perinatal death. Previous research has indicated the role of histone deacetylase 2 (HDAC2) in the pathogenesis of PE but the relevant molecular mechanisms are unknown. However, there is hitherto little information concerning the molecular mechanism behind HDAC2 in PE. Herein, we hypothesized that HDAC2 promotes trophoblast cell proliferation and this requires the involvement of microRNA-183 (miR-183), forkhead box protein A1 (FOXA1), and interleukin 8 (IL-8). We collected placental specimens from 30 PE affected and 30 normal pregnant women. HDAC2 and FOXA1 were poorly expressed while miR-183 and IL-8 were highly expressed in placental tissues in PE. In vitro, HDAC2 overexpression enhanced the proliferation, migration, and invasion of human trophoblast cells HTR-8/SVNEO. HDAC2 inhibited the expression of miR-183 by diminishing H4 acetylation in the miR-183 promoter region. miR-183 inhibition by its specific inhibitor increased the expression of FOXA1 and thus enhanced HTR-8/SVNEO cell proliferation, migration, and invasion. FOXA1, a transcriptional factor, enhanced HTR-8/SVNEO cell proliferation, migration, and invasion by inhibiting the transcription of IL-8. We also observed HDAC2 knockdown was lost upon FOXA1 overexpression, suggesting that HDAC2 could promote HTR-8/SVNEO proliferation, migration, and invasion through the miR-183/FOXA1/IL-8 pathway. In summary, the results highlighted the role of the HDAC2/miR-183/FOXA1/IL-8 pathway in PE pathogenesis and thus suggest a novel molecular target for PE.
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Affiliation(s)
- Hanhong Zhu
- Obstetrics Department, Linyi People's Hospital, Linyi, China
| | - Changxiu Wang
- Obstetrics Department, Linyi People's Hospital, Linyi, China
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18
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Yang M, Zhu Z, Zhuang Z, Bai Y, Wang S, Ge F. Proteogenomic Characterization of the Pathogenic Fungus Aspergillus flavus Reveals Novel Genes Involved in Aflatoxin Production. Mol Cell Proteomics 2020; 20:100013. [PMID: 33568340 PMCID: PMC7950108 DOI: 10.1074/mcp.ra120.002144] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 10/06/2020] [Accepted: 11/24/2020] [Indexed: 12/20/2022] Open
Abstract
Aspergillus flavus (A. flavus), a pathogenic fungus, can produce carcinogenic and toxic aflatoxins that are a serious agricultural and medical threat worldwide. Attempts to decipher the aflatoxin biosynthetic pathway have been hampered by the lack of a high-quality genome annotation for A. flavus. To address this gap, we performed a comprehensive proteogenomic analysis using high-accuracy mass spectrometry data for this pathogen. The resulting high-quality data set confirmed the translation of 8724 previously predicted genes and identified 732 novel proteins, 269 splice variants, 447 single amino acid variants, 188 revised genes. A subset of novel proteins was experimentally validated by RT-PCR and synthetic peptides. Further functional annotation suggested that a number of the identified novel proteins may play roles in aflatoxin biosynthesis and stress responses in A. flavus. This comprehensive strategy also identified a wide range of posttranslational modifications (PTMs), including 3461 modification sites from 1765 proteins. Functional analysis suggested the involvement of these modified proteins in the regulation of cellular metabolic and aflatoxin biosynthetic pathways. Together, we provided a high-quality annotation of A. flavus genome and revealed novel insights into the mechanisms of aflatoxin production and pathogenicity in this pathogen.
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Affiliation(s)
- Mingkun Yang
- School of Life Sciences, and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Zhuo Zhu
- School of Life Sciences, and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhenhong Zhuang
- School of Life Sciences, and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Youhuang Bai
- School of Life Sciences, and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shihua Wang
- School of Life Sciences, and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, China.
| | - Feng Ge
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
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19
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Ssu72 Regulates Fungal Development, Aflatoxin Biosynthesis and Pathogenicity in Aspergillus flavus. Toxins (Basel) 2020; 12:toxins12110717. [PMID: 33202955 PMCID: PMC7696088 DOI: 10.3390/toxins12110717] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/02/2020] [Accepted: 11/03/2020] [Indexed: 12/18/2022] Open
Abstract
The RNA polymerase II (Pol II) transcription process is coordinated by the reversible phosphorylation of its largest subunit-carboxy terminal domain (CTD). Ssu72 is identified as a CTD phosphatase with specificity for phosphorylation of Ser5 and Ser7 and plays critical roles in regulation of transcription cycle in eukaryotes. However, the biofunction of Ssu72 is still unknown in Aspergillus flavus, which is a plant pathogenic fungus and produces one of the most toxic mycotoxins-aflatoxin. Here, we identified a putative phosphatase Ssu72 and investigated the function of Ssu72 in A. flavus. Deletion of ssu72 resulted in severe defects in vegetative growth, conidiation and sclerotia formation. Additionally, we found that phosphatase Ssu72 positively regulates aflatoxin production through regulating expression of aflatoxin biosynthesis cluster genes. Notably, seeds infection assays indicated that phosphatase Ssu72 is crucial for pathogenicity of A. flavus. Furthermore, the Δssu72 mutant exhibited more sensitivity to osmotic and oxidative stresses. Taken together, our study suggests that the putative phosphatase Ssu72 is involved in fungal development, aflatoxin production and pathogenicity in A. flavus, and may provide a novel strategy to prevent the contamination of this pathogenic fungus.
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20
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Yang G, Cao X, Ma G, Qin L, Wu Y, Lin J, Ye P, Yuan J, Wang S. MAPK pathway-related tyrosine phosphatases regulate development, secondary metabolism and pathogenicity in fungus Aspergillus flavus. Environ Microbiol 2020; 22:5232-5247. [PMID: 32813277 DOI: 10.1111/1462-2920.15202] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 08/15/2020] [Accepted: 08/16/2020] [Indexed: 01/12/2023]
Abstract
Mitogen-activated protein kinase (MAPK) cascades are highly conserved in eukaryotic cells and are known to play crucial roles in the regulation of various cellular processes. However, compared with kinase-mediated phosphorylation, dephosphorylation catalysed by phosphatases has not been well characterized in filamentous fungi. In this study, we identified five MAPK pathway-related phosphatases (Msg5, Yvh1, Ptp1, Ptp2 and Oca2) and characterized their functions in Aspergillus flavus, which produces aflatoxin B1 (AFB1 ), one of the most toxic and carcinogenic secondary metabolites. These five phosphatases were identified as negative regulators of MAPK (Slt2, Fus3 and Hog1) pathways. Deletion of Msg5 and Yvh1 resulted in significant defects in conidiation, sclerotia formation, aflatoxin production and crop infection. Additionally, double knockout mutants (ΔMsg5/ΔPtp1, ΔMsg5/ΔPtp2 and ΔMsg5/ΔOca2) displayed similar defects to those observed in the ΔMsg5 single mutant, indicating that Msg5 plays a major role in the regulation of development and pathogenicity in A. flavus. Importantly, we found that the active site at C439 is essential for the function of the Msg5 phosphatase. Furthermore, the MAP kinase Fus3 was found to be involved in the regulation of development, aflatoxin biosynthesis and pathogenicity, and its conserved phosphorylation residues (Thr and Tyr) were critical for the full range of its functions in A. flavus. Overall, our results reveal that MAPK related tyrosine phosphatases play important roles in the regulation of development, secondary metabolism and pathogenicity in A. flavus, and could be developed as potential targets for preventing damage caused by this fungal pathogen.
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Affiliation(s)
- Guang Yang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xiaohong Cao
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Genli Ma
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Ling Qin
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yuanzhen Wu
- Department of Applied Biology, East China University of Science and Technology, Shanghai, 200237, China
| | - Jian Lin
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Peng Ye
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, 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, 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, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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21
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Zhang F, Huang L, Deng J, Tan C, Geng L, Liao Y, Yuan J, Wang S. A Cell Wall Integrity-Related MAP Kinase Kinase Kinase AflBck1 Is Required for Growth and Virulence in Fungus Aspergillus flavus. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:680-692. [PMID: 31922927 DOI: 10.1094/mpmi-11-19-0327-r] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Aspergillus flavus represents an important fungal pathogen, causing severe economic losses in crops. The mitogen-activated protein (MAP) kinase signaling pathway contributes to many physiological processes, but its precise role in A. flavus is not yet fully understood. In this study, we focused on the AflBck1 gene, which encodes a MAP kinase kinase kinase of the Slt2-MAPK pathway. Targeted deletion of AflBck1 led to a significant defect in growth and development, and a AflBck1-deleted mutant (∆AflBck1) showed higher sensitivity to cell-wall stress than wild type (WT). Importantly, we observed that ∆AflBck1 displayed an enhanced ability to produce aflatoxin, a potential carcinogenic mycotoxin. However, the pathogenicity of the ∆AflBck1 mutant was markedly reduced in peanut seeds. We also presented evidence that AflBck1 was genetically epistatic to AflMkk2 in the Slt2-MAPK pathway. Finally, we found that loss of the proline-rich region at the N terminus of AflBck1 affected the reproduction of A. flavus. Collectively, this study not only extended the understanding that the MAPK pathway regulated A. flavus pathogenicity but also provided a possible strategy to control A. flavus contamination.
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Affiliation(s)
- Feng Zhang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- School of Biological Science and Biotechnology, Minnan Normal University, Zhangzhou 363055, China
| | - Luhua Huang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jili Deng
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Can Tan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Longpo Geng
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yun Liao
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of 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 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 Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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22
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Bauer I, Gross S, Merschak P, Kremser L, Karahoda B, Bayram ÖS, Abt B, Binder U, Gsaller F, Lindner H, Bayram Ö, Brosch G, Graessle S. RcLS2F - A Novel Fungal Class 1 KDAC Co-repressor Complex in Aspergillus nidulans. Front Microbiol 2020; 11:43. [PMID: 32117098 PMCID: PMC7010864 DOI: 10.3389/fmicb.2020.00043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 01/09/2020] [Indexed: 12/15/2022] Open
Abstract
The fungal class 1 lysine deacetylase (KDAC) RpdA is a promising target for prevention and treatment of invasive fungal infection. RpdA is essential for survival of the most common air-borne mold pathogen Aspergillus fumigatus and the model organism Aspergillus nidulans. In A. nidulans, RpdA depletion induced production of previously unknown small bioactive substances. As known from yeasts and mammals, class 1 KDACs act as components of multimeric protein complexes, which previously was indicated also for A. nidulans. Composition of these complexes, however, remained obscure. In this study, we used tandem affinity purification to characterize different RpdA complexes and their composition in A. nidulans. In addition to known class 1 KDAC interactors, we identified a novel RpdA complex, which was termed RcLS2F. It contains ScrC, previously described as suppressor of the transcription factor CrzA, as well as the uncharacterized protein FscA. We show that recruitment of FscA depends on ScrC and we provide clear evidence that ΔcrzA suppression by ScrC depletion is due to a lack of transcriptional repression caused by loss of the novel RcLS2F complex. Moreover, RcLS2F is essential for sexual development and engaged in an autoregulatory feed-back loop.
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Affiliation(s)
- Ingo Bauer
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Silke Gross
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Petra Merschak
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Leopold Kremser
- Institute of Clinical Biochemistry, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Betim Karahoda
- Biology Department, Maynooth University, Maynooth, Ireland
| | | | - Beate Abt
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Ulrike Binder
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Fabio Gsaller
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Herbert Lindner
- Institute of Clinical Biochemistry, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Özgür Bayram
- Biology Department, Maynooth University, Maynooth, Ireland
| | - Gerald Brosch
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Stefan Graessle
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
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23
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Álvarez-Escribano I, Sasse C, Bok JW, Na H, Amirebrahimi M, Lipzen A, Schackwitz W, Martin J, Barry K, Gutiérrez G, Cea-Sánchez S, Marcos AT, Grigoriev IV, Keller NP, Braus GH, Cánovas D. Genome sequencing of evolved aspergilli populations reveals robust genomes, transversions in A. flavus, and sexual aberrancy in non-homologous end-joining mutants. BMC Biol 2019; 17:88. [PMID: 31711484 PMCID: PMC6844060 DOI: 10.1186/s12915-019-0702-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 09/19/2019] [Indexed: 01/19/2023] Open
Abstract
Background Aspergillus spp. comprises a very diverse group of lower eukaryotes with a high relevance for industrial applications and clinical implications. These multinucleate species are often cultured for many generations in the laboratory, which can unknowingly propagate hidden genetic mutations. To assess the likelihood of such events, we studied the genome stability of aspergilli by using a combination of mutation accumulation (MA) lines and whole genome sequencing. Results We sequenced the whole genomes of 30 asexual and 10 sexual MA lines of three Aspergillus species (A. flavus, A. fumigatus and A. nidulans) and estimated that each MA line accumulated mutations for over 4000 mitoses during asexual cycles. We estimated mutation rates of 4.2 × 10−11 (A. flavus), 1.1 × 10−11 (A. fumigatus) and 4.1 × 10−11 (A. nidulans) per site per mitosis, suggesting that the genomes are very robust. Unexpectedly, we found a very high rate of GC → TA transversions only in A. flavus. In parallel, 30 asexual lines of the non-homologous end-joining (NHEJ) mutants of the three species were also allowed to accumulate mutations for the same number of mitoses. Sequencing of these NHEJ MA lines gave an estimated mutation rate of 5.1 × 10−11 (A. flavus), 2.2 × 10−11 (A. fumigatus) and 4.5 × 10−11 (A. nidulans) per base per mitosis, which is slightly higher than in the wild-type strains and some ~ 5–6 times lower than in the yeasts. Additionally, in A. nidulans, we found a NHEJ-dependent interference of the sexual cycle that is independent of the accumulation of mutations. Conclusions We present for the first time direct counts of the mutation rate of filamentous fungal species and find that Aspergillus genomes are very robust. Deletion of the NHEJ machinery results in a slight increase in the mutation rate, but at a rate we suggest is still safe to use for biotechnology purposes. Unexpectedly, we found GC→TA transversions predominated only in the species A. flavus, which could be generated by the hepatocarcinogen secondary metabolite aflatoxin. Lastly, a strong effect of the NHEJ mutation in self-crossing was observed and an increase in the mutations of the asexual lines was quantified.
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Affiliation(s)
- Isidro Álvarez-Escribano
- Department of Genetics, Faculty of Biology, University of Seville, Seville, Spain.,Present Address: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas y Universidad de Sevilla, Seville, Spain
| | - Christoph Sasse
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University, Göttingen, Germany
| | - Jin Woo Bok
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Hyunsoo Na
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | | | - Anna Lipzen
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Wendy Schackwitz
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Joel Martin
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Kerrie Barry
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Gabriel Gutiérrez
- Department of Genetics, Faculty of Biology, University of Seville, Seville, Spain
| | - Sara Cea-Sánchez
- Department of Genetics, Faculty of Biology, University of Seville, Seville, Spain
| | - Ana T Marcos
- Department of Genetics, Faculty of Biology, University of Seville, Seville, Spain.,Present Address: Instituto para el Estudio de la Reproducción Humana (Inebir), Avda de la Cruz Roja 1, 41009, Sevilla, Spain
| | - Igor V Grigoriev
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA.,Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA, USA
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA.,Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Gerhard H Braus
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University, Göttingen, Germany
| | - David Cánovas
- Department of Genetics, Faculty of Biology, University of Seville, Seville, Spain.
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24
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Yang G, Yue Y, Ren S, Yang M, Zhang Y, Cao X, Wang Y, Zhang J, Ge F, Wang S. Lysine acetylation contributes to development, aflatoxin biosynthesis and pathogenicity in
Aspergillus flavus. Environ Microbiol 2019; 21:4792-4807. [DOI: 10.1111/1462-2920.14825] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/28/2019] [Accepted: 10/04/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Guang Yang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian ProvinceSchool of Life Sciences, Fujian Agriculture and Forestry University Fuzhou China
| | - Yuewei Yue
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian ProvinceSchool of Life Sciences, Fujian Agriculture and Forestry University Fuzhou China
| | - Silin Ren
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian ProvinceSchool of Life Sciences, Fujian Agriculture and Forestry University Fuzhou China
| | - Mingkun Yang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian ProvinceSchool of Life Sciences, Fujian Agriculture and Forestry University Fuzhou China
- Key Laboratory of Biopesticide and Chemical Biology of Education MinistrySchool of Life Sciences, Fujian Agriculture and Forestry University Fuzhou China
- Key Laboratory of Algal Biology, Institute of HydrobiologyChinese Academy of Sciences Wuhan China
| | - Yi Zhang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian ProvinceSchool of Life Sciences, Fujian Agriculture and Forestry University Fuzhou China
- Key Laboratory of Biopesticide and Chemical Biology of Education MinistrySchool of Life Sciences, Fujian Agriculture and Forestry University Fuzhou China
| | - Xiaohong Cao
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian ProvinceSchool of Life Sciences, Fujian Agriculture and Forestry University Fuzhou China
- Key Laboratory of Biopesticide and Chemical Biology of Education MinistrySchool of Life Sciences, Fujian Agriculture and Forestry University Fuzhou China
| | - Yinchun Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian ProvinceSchool of Life Sciences, Fujian Agriculture and Forestry University Fuzhou China
- Key Laboratory of Biopesticide and Chemical Biology of Education MinistrySchool of Life Sciences, Fujian Agriculture and Forestry University Fuzhou China
| | - Jia Zhang
- Key Laboratory of Algal Biology, Institute of HydrobiologyChinese Academy of Sciences Wuhan China
| | - Feng Ge
- Key Laboratory of Algal Biology, Institute of HydrobiologyChinese Academy of Sciences Wuhan China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian ProvinceSchool of Life Sciences, Fujian Agriculture and Forestry University Fuzhou China
- Key Laboratory of Biopesticide and Chemical Biology of Education MinistrySchool of Life Sciences, Fujian Agriculture and Forestry University Fuzhou China
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25
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Hanano A, Almousally I, Shaban M. Exposure of Aspergillus flavus NRRL 3357 to the Environmental Toxin, 2,3,7,8-Tetrachlorinated Dibenzo- p-Dioxin, Results in a Hyper Aflatoxicogenic Phenotype: A Possible Role for Caleosin/Peroxygenase (AfPXG). Front Microbiol 2019; 10:2338. [PMID: 31681203 PMCID: PMC6803392 DOI: 10.3389/fmicb.2019.02338] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 09/25/2019] [Indexed: 12/19/2022] Open
Abstract
Aflatoxins (AFs) as potent food contaminants are highly detrimental to human and animal health. The production of such biological toxins is influenced by environmental factors including pollutants, such as dioxins. Here, we report the biological feedback of an active AF-producer strain of A. flavus upon in vitro exposure to the most toxic congener of dioxins, the 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD). The phenotype of TCDD-exposed A. flavus was typified by a severe limitation in vegetative growth, activation of conidia formation and a significant boost in AF production. Furthermore, the level of reactive oxygen species (ROS) in fungal protoplast was increased (3.1- to 3.8-fold) in response to TCDD exposure at 10 and 50 ng mL-1, respectively. In parallel, superoxide dismutase (SOD) and catalase (CAT) activities were, respectively, increased by a factor of 2 and 3. In contrast to controls, transcript, protein and enzymatic activity of caleosin/peroxygenase (AfPXG) was also significantly induced in TCDD-exposed fungi. Subsequently, fungal cells accumulated fivefold more lipid droplets (LDs) than controls. Moreover, the TCDD-exposed fungi exhibited twofold higher levels of AFB1. Interestingly, TCDD-induced hyperaflatoxicogenicity was drastically abolished in the AfPXG-silencing strain of A. flavus, suggesting a role for AfPXG in fungal response to TCDD. Finally, TCDD-exposed fungi showed an increased in vitro virulence in terms of sporulation and AF production. The data highlight the possible effects of dioxin on aflatoxicogenicity of A. flavus and suggest therefore that attention should be paid in particular to the potential consequences of climate change on global food safety.
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Affiliation(s)
- Abdulsamie Hanano
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria, Damascus, Syria
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26
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Sadhasivam S, Shapiro OH, Ziv C, Barda O, Zakin V, Sionov E. Synergistic Inhibition of Mycotoxigenic Fungi and Mycotoxin Production by Combination of Pomegranate Peel Extract and Azole Fungicide. Front Microbiol 2019; 10:1919. [PMID: 31481948 PMCID: PMC6710344 DOI: 10.3389/fmicb.2019.01919] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/05/2019] [Indexed: 12/27/2022] Open
Abstract
Fungal plant pathogens cause considerable losses in yield and quality of field crops worldwide. In addition, under specific environmental conditions, many fungi, including such as some Fusarium and Aspergillus spp., are further able to produce mycotoxins while colonizing their host, which accumulate in human and animal tissues, posing a serious threat to consumer health. Extensive use of azole fungicides in crop protection stimulated the emergence of acquired azole resistance in some plant and human fungal pathogens. Combination treatments, which become popular in clinical practice, offer an alternative strategy for managing potentially resistant toxigenic fungi and reducing the required dosage of specific drugs. In the current study we tested the effect of pomegranate peel extract (PPE) on the growth and toxin production of the mycotoxigenic fungi Aspergillus flavus and Fusarium proliferatum, both alone and in combination with the azole fungicide prochloraz (PRZ). Using time-lapse microscopy and quantitative image analysis we demonstrate significant delay of conidial germination and hyphal elongation rate in both fungi following PPE treatment in combination with PRZ. Moreover, PPE treatment reduced aflatoxin production by A. flavus up to 97%, while a combined treatment with sub-inhibitory doses of PPE and PRZ resulted in complete inhibition of toxin production over a 72 h treatment. These findings were supported by qRT-PCR analysis, showing down-regulation of key genes involved in the aflatoxin biosynthetic pathway under combined PPE/PRZ treatment al low concentrations. Our results provide first evidence for synergistic effects between the commercial drug PRZ and natural compound PPE. Future application of these findings may allow to reduce the required dosage of PRZ, and possibly additional azole drugs, to inhibit mycotoxigenic fungi, ultimately reducing potential concerns over exposure to high doses of these potentially harmful fungicides.
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Affiliation(s)
- Sudharsan Sadhasivam
- Department of Food Quality and Safety, Institute for Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion, Israel
| | - Orr H. Shapiro
- Department of Food Quality and Safety, Institute for Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion, Israel
| | - Carmit Ziv
- Department of Postharvest Science, Institute for Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion, Israel
| | - Omer Barda
- Department of Food Quality and Safety, Institute for Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion, Israel
| | - Varda Zakin
- Department of Food Quality and Safety, Institute for Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion, Israel
| | - Edward Sionov
- Department of Food Quality and Safety, Institute for Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion, Israel
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