1
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Zaineldin AI, Elsebaey E, Habotta OA, Abdo WS, Basuini MFE, Dawood MAO. Mitigating Aflatoxin B 1-Induced Growth Impairment and Hepatic Stress in Nile Tilapia (Oreochromis niloticus): Comparative Efficacy of Saccharomyces cerevisiae and Silicate-Based Detoxifiers. Probiotics Antimicrob Proteins 2024:10.1007/s12602-023-10210-2. [PMID: 38175392 DOI: 10.1007/s12602-023-10210-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2023] [Indexed: 01/05/2024]
Abstract
The objective of this study was to detect the effects of acute aflatoxin B1 (AFB1) exposure in Nile tilapia (Oreochromis niloticus) and the effectiveness of Saccharomyces cerevisiae and silicate in reducing these effects. Two hundred and forty Nile tilapia fingerlings (16 ± 0.5 g) were randomly assigned to four experimental groups, each with 60 fish and three replicates. Control basal diet (Diet 1) and three test diets were formulated, where Diet 2 was supplemented with 200 ppb AFB1. Diets 3 and 4 were intoxicated with AFB1 (200 ppb) and supplemented with 0.5% S. cerevisiae or 0.5%, respectively. After 60 days, Diet 1 had considerably greater growth characteristics than the other groups (p < 0.05). Diet 2 revealed a reduced (p < 0.05) survival rate after 1 month of exposure. In addition, Diet 1 showed higher (p < 0.05) total protein and albumin levels than Diets 3 and 4. AFB1 residues were detected in the liver in fish-fed Diet 2, Diet 4, and Diet 3. Alanine aminotransferase, aspartate aminotransferase, creatinine, and urea levels increased (p < 0.05) in fish-fed Diet 2. The glutathione peroxidase, lysozyme, and catalase activity were decreased (p < 0.05) in the fish-fed Diet 2. The malondialdehyde level was significantly higher in fish given Diet 2 (p < 0.05) than in fish-fed Diets 3 and 4. Histopathological investigation of fish-fed Diet 2 revealed impaired liver and spleen; however, both treatments (Diets 3 and 4) successfully lowered inflammation and preserved liver and spleen integrities. In conclusion, AFB1 impaired growth performance and posed a severe health risk to Nile tilapia. Furthermore, S. cerevisiae alleviated the contamination of AFB1 effects more efficiently than silicate employed for toxin adsorption.
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Affiliation(s)
- Amr I Zaineldin
- Agriculture Research Center, Animal Health Research Institute (AHRI-DOKI), Kafrelsheikh, Egypt.
| | - Ehab Elsebaey
- Agriculture Research Center, Animal Health Research Institute (AHRI-DOKI), Kafrelsheikh, Egypt
| | - Ola A Habotta
- Department of Forensic Medicine and Toxicology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt
| | - Walied S Abdo
- Department of Pathology, Faculty of Veterinary Medicine, Kafrelsheikh University, Kafrelsheikh, 33516, Egypt
| | - Mohammed F El Basuini
- Faculty of Agriculture, Tanta University, Tanta, 31527, Egypt
- King Salman International University, El Tor, South Sinai, Nuweiba, 46618, Egypt
| | - Mahmoud A O Dawood
- Department of Animal Production, Faculty of Agriculture, Kafrelsheikh University, Kafrelsheikh, 33516, Egypt
- The Centre for Applied Research On the Environment and Sustainability, The American University in Cairo, Cairo, Egypt
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2
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Qiu M, Qiu L, Deng Q, Fang Z, Sun L, Wang Y, Gooneratne R, Zhao J. L-Cysteine hydrochloride inhibits Aspergillus flavus growth and AFB 1 synthesis by disrupting cell structure and antioxidant system balance. JOURNAL OF HAZARDOUS MATERIALS 2023; 459:132218. [PMID: 37552922 DOI: 10.1016/j.jhazmat.2023.132218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 07/26/2023] [Accepted: 08/02/2023] [Indexed: 08/10/2023]
Abstract
Aflatoxin B1 (AFB1) is the most potent known naturally occurring carcinogen and pose an immense threat to food safety and human health. L-Cysteine hydrochloride (L-CH) is a food additive often used as a fruit and vegetable preservative and also to approved bread consistency. In this study, we investigated the effects and mechanisms of L-CH as an antimicrobial on the growth of Aspergillus flavus (A. flavus) and AFB1 biosynthesis. L-CH significantly inhibited A. flavus mycelial growth, affected mycelial morphology and AFB1 synthesis. Furthermore, L-CH induced glutathione (GSH) synthesis which scavenged intracellular reactive oxygen species (ROS). RNA-Seq indicated that L-CH inhibited hyphal branching, and spore and sclerotia formation by controlling cell wall and spore development-related genes. Activation of the GSH metabolic pathway eliminated intracellular ROS, leading to hyphal dwarfing. L-CH treatment downregulated most of the Aflatoxin (AF) cluster genes and aflS, aflR, AFLA_091090 transcription factors. This study provides new insights into the molecular mechanism of L-CH control of A. flavus and AFB1 foundation. We believe that L-CH could be used as a food additive to control AFB1 in foods and also in the environment.
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Affiliation(s)
- Mei Qiu
- College of Food Science and Technology, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Key Laboratory of Advanced Processing of Aquatic Products of Guangdong Higher Education Institution, Zhanjiang 524088, China
| | - Lihong Qiu
- Department of Clinical Laboratory, Affiliated Hospital of Guangdong Medical University, Zhanjiang 524001, China
| | - Qi Deng
- College of Food Science and Technology, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Key Laboratory of Advanced Processing of Aquatic Products of Guangdong Higher Education Institution, Zhanjiang 524088, China.
| | - Zhijia Fang
- College of Food Science and Technology, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Key Laboratory of Advanced Processing of Aquatic Products of Guangdong Higher Education Institution, Zhanjiang 524088, China
| | - Lijun Sun
- College of Food Science and Technology, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Key Laboratory of Advanced Processing of Aquatic Products of Guangdong Higher Education Institution, Zhanjiang 524088, China
| | - Yaling Wang
- College of Food Science and Technology, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Key Laboratory of Advanced Processing of Aquatic Products of Guangdong Higher Education Institution, Zhanjiang 524088, China
| | - Ravi Gooneratne
- Department of Wine, Food and Molecular Biosciences, Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln 7647, New Zealand
| | - Jian Zhao
- School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
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3
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Bákány B, Antal R, Szentesi P, Emri T, Leiter É, Csernoch L, Keller NP, Pócsi I, Dienes B. The bZIP-type transcription factors NapA and RsmA modulate the volumetric ratio and the relative superoxide ratio of mitochondria in Aspergillus nidulans. Biol Futur 2023; 74:337-346. [PMID: 37814124 DOI: 10.1007/s42977-023-00184-1] [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: 03/26/2023] [Accepted: 09/24/2023] [Indexed: 10/11/2023]
Abstract
Basic leucine zipper (bZIP) transcription factors are crucial components of differentiation, cellular homeostasis and the environmental stress defense of eukaryotes. In this work, we further studied the consequence of gene deletion and overexpression of two bZIP transcription factors, NapA and RsmA, on superoxide production, mitochondrial morphology and hyphal diameter of Aspergillus nidulans. We have found that reactive oxygen species production was influenced by both gene deletion and overexpression of napA under tert-butylhydroperoxide (tBOOH) elicited oxidative stress. Furthermore, gene expression of napA negatively correlated with mitochondrial volumetric ratio as well as sterigmatocystin production of A. nidulans. High rsmA expression was accompanied with elevated relative superoxide ratio in the second hyphal compartment. A negative correlation between the expression of rsmA and catalase enzyme activity or mitochondrial volumetric ratio was also confirmed by statistical analysis. Hyphal diameter was independent on either rsmA and napA expression as well as 0.2 mM tBOOH treatment.
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Affiliation(s)
- Bernadett Bákány
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
- Doctoral School of Molecular Medicine, University of Debrecen, Debrecen, Hungary
- Institute of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Réka Antal
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Péter Szentesi
- Institute of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- ELRN-UD Cell Physiology Research Group, Debrecen, Hungary
| | - Tamás Emri
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
- ELRN-UD Fungal Stress Biology Research Group, Debrecen, Hungary
| | - Éva Leiter
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary.
- ELRN-UD Fungal Stress Biology Research Group, Debrecen, Hungary.
| | - László Csernoch
- Institute of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- ELRN-UD Cell Physiology Research Group, Debrecen, Hungary
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, USA
- Department of Plant Pathology, University of Wisconsin, Madison, USA
| | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
- ELRN-UD Fungal Stress Biology Research Group, Debrecen, Hungary
| | - Beatrix Dienes
- Institute of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- ELRN-UD Cell Physiology Research Group, Debrecen, Hungary
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4
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Zhang Y, Zhang F, Shao W, Chen W, Zhang Z, Shi D, Chen C. Phenamacril and carbendazim regulate trichothecene mycotoxin synthesis by affecting ROS levels in F. asiaticum. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 194:105506. [PMID: 37532325 DOI: 10.1016/j.pestbp.2023.105506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/09/2023] [Accepted: 06/22/2023] [Indexed: 08/04/2023]
Abstract
Fusarium head blight caused by Fusarium asiaticum is an important cereal crop disease, and the trichothecene mycotoxins produced by F. asiaticum can contaminate wheat grain, which is very harmful to humans and animals. To effectively control FHB in large areas, the application of fungicides is the major strategy; however, the application of different types of fungicides has varying influences on the accumulation of trichothecene mycotoxins in F. asiaticum. In this study, phenamacril inhibited trichothecene mycotoxin accumulation in F. asiaticum; however, carbendazim (N-1H-benzimidazol-2-yl-carbamic acid, methyl ester) induced trichothecene mycotoxin accumulation. Additionally, phenamacril led to a lower level of reactive oxygen species (ROS) by inducing gene expression of the catalase and superoxide dismutase (SOD) pathways in F. asiaticum, whereas carbendazim stimulated ROS accumulation by inhibiting gene expression of the catalase and SOD pathways. Based on these results, we conclude that phenamacril and carbendazim regulate trichothecene mycotoxin synthesis by affecting ROS levels in F. asiaticum.
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Affiliation(s)
- Yu Zhang
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, Department of Plant Pathology, College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou 311300, China
| | - Fuyu Zhang
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, Department of Plant Pathology, College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou 311300, China
| | - Wenyong Shao
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Wenchan Chen
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhihui Zhang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Dongya Shi
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Changjun Chen
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
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5
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Li Z, Sun Y, Gu L, Wang Y, Xu M, Zhou Y, Hu Y, Ma W. Ar-turmerone suppresses Aspergillus flavus growth and aflatoxin accumulation: Finding a new antifungal agent based on stored maize. Food Res Int 2023; 168:112735. [PMID: 37120196 DOI: 10.1016/j.foodres.2023.112735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 04/03/2023]
Abstract
Aspergillus flavus (A. flavus) is a common saprophytic pathogenic fungus that produces toxic and carcinogenic aflatoxins prone to contaminate food. Here, we optimized the synthesis method of Ar-turmerone, the main active ingredient in turmeric essential oil, improved its yield and reduced the operation requirements. Moreover, 50.0 μg/mL Ar-turmerone 100.0 % inhibited the colonies growth, spore germination, mycelium biomass and aflatoxin accumulation in 7 days. 2,018 differentially expressed genes (DEGs) such as catA, ppoC, erg7, erg6 and aflO related to the A. flavus growth and aflatoxin product were significantly downregulated including 45 DEGs were 100.0 % suppressed. Besides, Ar-turmerone greatly reduced A. flavus in maize, the optimal storage conditions for maize to avoid A. flavus contamination were determined as 0.940 aw, 400.0 μg/mL Ar-turmerone, and 16.0 °C. Satisfactory odor, luster, taste, and mildew in maize observed after three weeks of storage under the optimal conditions. Thus, Ar-turmerone can be used as a potential food antifungal agent against A. flavus growth and aflatoxin accumulation during food storage.
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Affiliation(s)
- Zheyu Li
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610052, China.
| | - Yanan Sun
- Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, College of Food and Biological Engineering, Chengdu University, Chengdu 610106, People's Republic of China
| | - Linghui Gu
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610052, China
| | - Yuchi Wang
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610052, China
| | - Mingqin Xu
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610052, China
| | - Yunhao Zhou
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610052, China
| | - Yichen Hu
- Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, College of Food and Biological Engineering, Chengdu University, Chengdu 610106, People's Republic of China.
| | - Wenbo Ma
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610052, China.
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6
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Xie L, Yang Q, Wu Y, Xiao J, Qu H, Jiang Y, Li T. Fumonisin B1 Biosynthesis Is Associated with Oxidative Stress and Plays an Important Role in Fusarium proliferatum Infection on Banana Fruit. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:5372-5381. [PMID: 36947157 DOI: 10.1021/acs.jafc.3c00179] [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: 06/18/2023]
Abstract
Fungal response to oxidative stress during infection on postharvest fruit is largely unknown. Here, we found that hydrogen peroxide (H2O2) treatment inhibited the growth of Fusarium proliferatum causing crown rot of banana fruit, confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observation. H2O2 exposure increased endogenous reactive oxygen species (ROS) and fumonisin B1 (FB1) production in F. proliferatum, possibly by modulating FUM or ROS-related gene expression. Importantly, H2O2 treatment inhibited F. proliferatum growth in vivo but induced FB1 accumulation in banana peel. Finally, we constructed the FpFUM21 deletion mutant (ΔFpfum21) of F. proliferatum that was attenuated in FB1 biosynthesis and less tolerant to oxidative stress. Moreover, the ΔFpfum21 strain was less virulent compared to the wild type (WT) due to the inability to induce FB1 production in the banana host. These results suggested that FB1 biosynthesis is associated with oxidative stress in F. proliferatum and contributes to fungal infection on banana fruit.
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Affiliation(s)
- Lihong Xie
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, 723 Xingke Road, Tianhe District, Guangzhou 510650, China
- South China National Botanical Garden, Guangzhou 510650, China
- University of Chinese Academy of Sciences, Beijing 100039, China
| | - Qiuxiao Yang
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, 723 Xingke Road, Tianhe District, Guangzhou 510650, China
- South China National Botanical Garden, Guangzhou 510650, China
- University of Chinese Academy of Sciences, Beijing 100039, China
| | - Yanfei Wu
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, 723 Xingke Road, Tianhe District, Guangzhou 510650, China
- South China National Botanical Garden, Guangzhou 510650, China
- University of Chinese Academy of Sciences, Beijing 100039, China
| | - Jianbo Xiao
- Nutrition and Bromatology Group, Department of Analytical and Food Chemistry, Faculty of Sciences, Universidade de Vigo, Ourense 32004, Spain
| | - Hongxia Qu
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, 723 Xingke Road, Tianhe District, Guangzhou 510650, China
- South China National Botanical Garden, Guangzhou 510650, China
| | - Yueming Jiang
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, 723 Xingke Road, Tianhe District, Guangzhou 510650, China
- South China National Botanical Garden, Guangzhou 510650, China
| | - Taotao Li
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, 723 Xingke Road, Tianhe District, Guangzhou 510650, China
- South China National Botanical Garden, Guangzhou 510650, China
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7
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Jiang L, Guan X, Liu H, Chang X, Sun J, Sun C, Zhao C. Improved Production of Recombinant Carboxylesterase FumDM by Co-Expressing Molecular Chaperones in Pichia pastoris. Toxins (Basel) 2023; 15:156. [PMID: 36828470 PMCID: PMC9960120 DOI: 10.3390/toxins15020156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/11/2023] [Accepted: 02/11/2023] [Indexed: 02/16/2023] Open
Abstract
Fumonisins (FBs) are mycotoxins that threaten public health and food safety worldwide. Enzymatic degradation of Fumonisin B1 (FB1) through decarboxylation has attracted much attention, whereas application of FB1 carboxylesterase in detoxification requires more effective expression of the recombinant carboxylesterase. In this study, the carboxylesterase FumDM from Sphingopyxis sp. ASAG22 was codon-optimized and co-expressed with five different molecular chaperones (PDI, CPR5, ERO1, HAC1, and Bip) in order to improve the expression level of FumDM in Pichia pastoris (also known as Komagataella phaffii) GS115. The co-expression of different chaperones caused varying degrees of improvement in FumDM activity for FB1. The enzyme activities of recombinant strains over-expressing PDI and CPR5 reached the highest levels of 259.47 U/mL and 161.34 U/mL, 635% and 357% higher than the original enzyme activity, respectively. Transcriptomic analysis of the two recombinant strains in comparison with the control strain showed that the correct folding of proteins assisted by molecular chaperones played a key role in the improvement of FumDM expression and its enzyme activity. This study demonstrated that co-expression of carboxylesterase FumDM and folding chaperones was an efficient strategy and therefore might inspire new perspectives on the improvement of carboxylesterase for detoxification of FB1.
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Affiliation(s)
- Lixiang Jiang
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Academy of National Food and Strategic Reserves Administration, Beijing 100037, China
| | - Xiao Guan
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Hujun Liu
- Academy of National Food and Strategic Reserves Administration, Beijing 100037, China
| | - Xiaojiao Chang
- Academy of National Food and Strategic Reserves Administration, Beijing 100037, China
| | - Jing Sun
- Academy of National Food and Strategic Reserves Administration, Beijing 100037, China
| | - Changpo Sun
- Academy of National Food and Strategic Reserves Administration, Beijing 100037, China
| | - Chengcheng Zhao
- Academy of National Food and Strategic Reserves Administration, Beijing 100037, China
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8
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Loi M, Logrieco AF, Pusztahelyi T, Leiter É, Hornok L, Pócsi I. Advanced mycotoxin control and decontamination techniques in view of an increased aflatoxin risk in Europe due to climate change. Front Microbiol 2023; 13:1085891. [PMID: 36762096 PMCID: PMC9907446 DOI: 10.3389/fmicb.2022.1085891] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 12/15/2022] [Indexed: 01/11/2023] Open
Abstract
Aflatoxins are toxic secondary metabolites produced by Aspergillus spp. found in staple food and feed commodities worldwide. Aflatoxins are carcinogenic, teratogenic, and mutagenic, and pose a serious threat to the health of both humans and animals. The global economy and trade are significantly affected as well. Various models and datasets related to aflatoxins in maize have been developed and used but have not yet been linked. The prevention of crop loss due to aflatoxin contamination is complex and challenging. Hence, the set-up of advanced decontamination is crucial to cope with the challenge of climate change, growing population, unstable political scenarios, and food security problems also in European countries. After harvest, decontamination methods can be applied during transport, storage, or processing, but their application for aflatoxin reduction is still limited. Therefore, this review aims to investigate the effects of environmental factors on aflatoxin production because of climate change and to critically discuss the present-day and novel decontamination techniques to unravel gaps and limitations to propose them as a tool to tackle an increased aflatoxin risk in Europe.
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Affiliation(s)
- Martina Loi
- Institute of Sciences of Food Production, National Research Council, Bari, Italy,*Correspondence: Martina Loi, ✉
| | - Antonio F. Logrieco
- Institute of Sciences of Food Production, National Research Council, Bari, Italy
| | - Tünde Pusztahelyi
- Central Laboratory of Agricultural and Food Products, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary
| | - Éva Leiter
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, Institute of Biotechnology, University of Debrecen, Debrecen, Hungary,ELRN-UD Fungal Stress Biology Research Group, University of Debrecen, Debrecen, Hungary
| | - László Hornok
- Hungarian University of Agriculture and Life Sciences, Gödöllő, Hungary
| | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, Institute of Biotechnology, University of Debrecen, Debrecen, Hungary,ELRN-UD Fungal Stress Biology Research Group, University of Debrecen, Debrecen, Hungary
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9
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Wang W, Liang X, Li Y, Wang P, Keller NP. Genetic Regulation of Mycotoxin Biosynthesis. J Fungi (Basel) 2022; 9:jof9010021. [PMID: 36675842 PMCID: PMC9861139 DOI: 10.3390/jof9010021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 12/20/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022] Open
Abstract
Mycotoxin contamination in food poses health hazards to humans. Current methods of controlling mycotoxins still have limitations and more effective approaches are needed. During the past decades of years, variable environmental factors have been tested for their influence on mycotoxin production leading to elucidation of a complex regulatory network involved in mycotoxin biosynthesis. These regulators are putative targets for screening molecules that could inhibit mycotoxin synthesis. Here, we summarize the regulatory mechanisms of hierarchical regulators, including pathway-specific regulators, global regulators and epigenetic regulators, on the production of the most critical mycotoxins (aflatoxins, patulin, citrinin, trichothecenes and fumonisins). Future studies on regulation of mycotoxins will provide valuable knowledge for exploring novel methods to inhibit mycotoxin biosynthesis in a more efficient way.
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Affiliation(s)
- Wenjie Wang
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
- Institute of Food Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
- Correspondence: (W.W.); (N.P.K.)
| | - Xinle Liang
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
- Institute of Food Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Yudong Li
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
- Institute of Food Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Pinmei Wang
- Ocean College, Zhejiang University, Zhoushan 316021, China
| | - Nancy P. Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Correspondence: (W.W.); (N.P.K.)
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10
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Wu S, Zhang Q, Zhang W, Huang W, Kong Q, Liu Q, Li W, Zou X, Liu CM, Yan S. Linolenic Acid-Derived Oxylipins Inhibit Aflatoxin Biosynthesis in Aspergillus flavus through Activation of Imizoquin Biosynthesis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:15928-15944. [PMID: 36508213 PMCID: PMC9785051 DOI: 10.1021/acs.jafc.2c06230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/24/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
Oxylipins play important signaling roles in aflatoxin (AF) biosynthesis in Aspergillus flavus. We previously showed that exogenous supply of autoxidated linolenic acid (AL) inhibited AF biosynthesis in A. flavus via oxylipins, but the molecular mechanism is still unknown. Here, we performed multiomics analyses of A. flavus grown in media with or without AL. Targeted metabolite analyses and quantitative reverse transcription (qRT)-polymerase chain reaction (PCR) showed that the imizoquin (IMQ) biosynthetic pathway was distinctly upregulated in the presence of AL. 13C-glucose labeling confirmed in parallel that the tricarboxylic acid cycle was also enhanced by AL, consistent with observed increases in mycelial growth. Moreover, we integrated thermal proteome profiling and molecular dynamics simulations to identify a potential receptor of AL; AL was found to interact with a transporter (ImqJ) located in the IMQ gene cluster, primarily through hydrophobic interactions. Further analyses of strains with an IMQ pathway transcription factor overexpressed or knocked out confirmed that this pathway was critical for AL-mediated inhibition of AF biosynthesis. Comparison of 22 assembled A. flavus and Aspergillus oryzae genomes showed that genes involved in the IMQ pathway were positively selected in A. oryzae. Taken together, the results of our study provide novel insights into oxylipin-mediated regulation of AF biosynthesis and suggest potential methods for preventing AF contamination of crops.
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Affiliation(s)
- Shaowen Wu
- Guangdong
Key Laboratory for Crop Germplasm Resources Preservation and Utilization,
Agro-biological Gene Research Center, Guangdong
Academy of Agricultural Sciences, Guangzhou510640, China
| | - Qunjie Zhang
- Guangdong
Key Laboratory for Crop Germplasm Resources Preservation and Utilization,
Agro-biological Gene Research Center, Guangdong
Academy of Agricultural Sciences, Guangzhou510640, China
- Institution
of Genomics and Bioinformatics, South China
Agricultural University, Guangzhou510642, China
| | - Wenyang Zhang
- Guangdong
Key Laboratory for Crop Germplasm Resources Preservation and Utilization,
Agro-biological Gene Research Center, Guangdong
Academy of Agricultural Sciences, Guangzhou510640, China
| | - Wenjie Huang
- Guangdong
Key Laboratory for Crop Germplasm Resources Preservation and Utilization,
Agro-biological Gene Research Center, Guangdong
Academy of Agricultural Sciences, Guangzhou510640, China
| | - Qian Kong
- Guangdong
Key Laboratory for Crop Germplasm Resources Preservation and Utilization,
Agro-biological Gene Research Center, Guangdong
Academy of Agricultural Sciences, Guangzhou510640, China
| | - Qinjian Liu
- Guangdong
Key Laboratory for Crop Germplasm Resources Preservation and Utilization,
Agro-biological Gene Research Center, Guangdong
Academy of Agricultural Sciences, Guangzhou510640, China
| | - Wenyan Li
- Guangdong
Key Laboratory for Crop Germplasm Resources Preservation and Utilization,
Agro-biological Gene Research Center, Guangdong
Academy of Agricultural Sciences, Guangzhou510640, China
| | - Xinlu Zou
- Guangdong
Key Laboratory for Crop Germplasm Resources Preservation and Utilization,
Agro-biological Gene Research Center, Guangdong
Academy of Agricultural Sciences, Guangzhou510640, China
| | - Chun-Ming Liu
- Key
Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Fragrant Hill, Beijing100093, China
| | - Shijuan Yan
- Guangdong
Key Laboratory for Crop Germplasm Resources Preservation and Utilization,
Agro-biological Gene Research Center, Guangdong
Academy of Agricultural Sciences, Guangzhou510640, China
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11
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Pérez-Sánchez A, Bibián ME, Barrios-González J. The Biosynthesis of Penicillin and Cephalosporin C are Regulated by ROS at Transcriptional Level. Curr Microbiol 2022; 79:243. [PMID: 35796838 DOI: 10.1007/s00284-022-02935-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 06/14/2022] [Indexed: 11/30/2022]
Abstract
In a recent work we showed that, besides lovastatin, ROS also accumulate during the production phase in Pencillium chrysogenum and in Acremonium chrysogenum, and that these ROS regulate the biosynthesis of penicillin and cephalosporin C. In the present study, we investigated the level at which this positive regulation is exerted. Internal ROS levels were manipulated, i.e., increased or decreased, in the production phase of the respective fermentations. Penicillin production decreased by 51.2% when internal ROS concentration was diminished by 50%, while a 62% production increase was observed when ROS were increased (62%). Similarly, Cephalosporin production decreased (35%) with antioxidants and increased (54.1%) with exogenous ROS. Expression analysis of the respective pcbAB genes, encoding the non-ribosomal peptide synthetase enzymes, was performed. Results showed down regulation of these genes in fermentations with lower ROS content, and upregulation in the cultures with higher ROS content, in both species. This showed that ROS regulation of penicillin in P. chrysogenum and of cephalosporin C in A. chrysogenum, is exerted at transcriptional level. In silico analysis of the pcbAB gene promoters in both species, suggested that this regulation could be mediated by stress-response transcription factors like Yap1, SrrA and/or MsnA, and/or by the Hap complex.
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Affiliation(s)
- A Pérez-Sánchez
- Departamento de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa, Av. Rafael Atlixco No. 186. Col. Vicentina, Iztapalapa, C.P. 09340, Mexico City, Mexico
| | - M E Bibián
- Departamento de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa, Av. Rafael Atlixco No. 186. Col. Vicentina, Iztapalapa, C.P. 09340, Mexico City, Mexico
| | - J Barrios-González
- Departamento de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa, Av. Rafael Atlixco No. 186. Col. Vicentina, Iztapalapa, C.P. 09340, Mexico City, Mexico.
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12
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Wang K, Wang Z, Xu W. Induced oxidative equilibrium damage and reduced toxin synthesis in Fusarium oxysporum f. sp. niveum by secondary metabolites from Bacillus velezensis WB. FEMS Microbiol Ecol 2022; 98:6626022. [PMID: 35776952 DOI: 10.1093/femsec/fiac080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 06/15/2022] [Accepted: 06/29/2022] [Indexed: 11/14/2022] Open
Abstract
In this study, the antifungal mechanism of secondary metabolites from the WB strain against Fusarium oxysporum f. sp. niveum (Fon) was investigated. The WB strain induced the accumulation of reactive oxygen species (ROS) in Fon hyphae and caused morphological changes, including surface subsidence and shrinkage deformation. The cell-free supernatants (CFSs) from WB treatment caused a significant increase in superoxide dismutase, catalase, peroxidase and glutathione reductase activities and the contents of soluble protein and malondialdehyde. Additionally, CFSs from WB decreased the fusaric acid concentration in Fon. Transcriptome analysis revealed that the expression of some antioxidant-related genes was upregulated and that the expression of mycotoxin-related genes was downregulated. Four polypeptide compounds from the WB strain, including iturin A, fengycin, surfactin and bacitracin, were identified by UHPLC-ESI-MS/MS analysis and complete genome mining. RT-qPCR and a quantitative analysis confirmed that the presence of Fon induced the expression of polypeptide genes and elevated polypeptide production. The combined minimum inhibitory concentration and quantitative analysis of four polypeptides revealed that iturin A, fengycin, surfactin and bacitracin might be responsible for inhibiting the growth of Fon. In conclusion, secondary metabolites from strain WB exhibited antifungal effects on Fon by triggering oxidative stress and decreasing toxin levels.
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Affiliation(s)
- Kexin Wang
- College of Life Science and Agroforestry, Qiqihar University, Qiqihar 161006, China.,Heilongjiang Provincial Technology Innovation Center of Agromicrobial Preparation Industrialization, Qiqihar 161006, China
| | - Zhigang Wang
- College of Life Science and Agroforestry, Qiqihar University, Qiqihar 161006, China.,Heilongjiang Provincial Technology Innovation Center of Agromicrobial Preparation Industrialization, Qiqihar 161006, China
| | - Weihui Xu
- College of Life Science and Agroforestry, Qiqihar University, Qiqihar 161006, China.,Heilongjiang Provincial Technology Innovation Center of Agromicrobial Preparation Industrialization, Qiqihar 161006, China
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13
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Li Q, Zhu X, Zhao Y, Xie Y. The antifungal activity of o-vanillin against Aspergillus flavus via disrupting ergosterol biosynthesis and promoting oxidative stress, and an RNA-seq analysis thereof. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2022.113635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Li Q, Zhao Y, Zuo X, Guo F, Li Y, Xie Y. Paeonol inhibits Aspergillus flavus via disrupting ergosterol biosynthesis, redox metabolism, and aflatoxin biosynthesis on rice. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2022.113587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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15
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Abbas A, Wright CW, El-Sawi N, Yli-Mattila T, Malinen AM. A methanolic extract of Zanthoxylum bungeanum modulates secondary metabolism regulator genes in Aspergillus flavus and shuts down aflatoxin production. Sci Rep 2022; 12:5995. [PMID: 35397670 PMCID: PMC8994782 DOI: 10.1038/s41598-022-09913-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 03/29/2022] [Indexed: 12/30/2022] Open
Abstract
Aflatoxin B1 (AFB1) is a food-borne toxin produced by Aspergillus flavus and a few similar fungi. Natural anti-aflatoxigenic compounds are used as alternatives to chemical fungicides to prevent AFB1 accumulation. We found that a methanolic extract of the food additive Zanthoxylum bungeanum shuts down AFB1 production in A. flavus. A methanol sub-fraction (M20) showed the highest total phenolic/flavonoid content and the most potent antioxidant activity. Mass spectrometry analyses identified four flavonoids in M20: quercetin, epicatechin, kaempferol-3-O-rhamnoside, and hyperoside. The anti-aflatoxigenic potency of M20 (IC50: 2-4 µg/mL) was significantly higher than its anti-proliferation potency (IC50: 1800-1900 µg/mL). RNA-seq data indicated that M20 triggers significant transcriptional changes in 18 of 56 secondary metabolite pathways in A. flavus, including repression of the AFB1 biosynthesis pathway. Expression of aflR, the specific activator of the AFB1 pathway, was not changed by M20 treatment, suggesting that repression of the pathway is mediated by global regulators. Consistent with this, the Velvet complex, a prominent regulator of secondary metabolism and fungal development, was downregulated. Decreased expression of the conidial development regulators brlA and Medusa, genes that orchestrate redox responses, and GPCR/oxylipin-based signal transduction further suggests a broad cellular response to M20. Z. bungeanum extracts may facilitate the development of safe AFB1 control strategies.
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Affiliation(s)
- Asmaa Abbas
- Department of Life Technologies, University of Turku, 20014, Turku, Finland.,School of Pharmacy and Medical Sciences, University of Bradford, West Yorkshire, BD7 1DP, UK.,Department of Chemistry, Faculty of Science, Sohag University, Sohag, 82524, Egypt
| | - Colin W Wright
- School of Pharmacy and Medical Sciences, University of Bradford, West Yorkshire, BD7 1DP, UK
| | - Nagwa El-Sawi
- Department of Chemistry, Faculty of Science, Sohag University, Sohag, 82524, Egypt
| | - Tapani Yli-Mattila
- Department of Life Technologies, University of Turku, 20014, Turku, Finland
| | - Anssi M Malinen
- Department of Life Technologies, University of Turku, 20014, Turku, Finland.
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16
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Pérez-Pérez WD, Carrasco-Navarro U, García‑Estrada C, Kosalková K, Gutiérrez-Ruíz MC, Barrios-González J, Fierro F. bZIP transcription factors PcYap1 and PcRsmA link oxidative stress response to secondary metabolism and development in Penicillium chrysogenum. Microb Cell Fact 2022; 21:50. [PMID: 35366869 PMCID: PMC8977021 DOI: 10.1186/s12934-022-01765-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 02/27/2022] [Indexed: 01/23/2023] Open
Abstract
Abstract
Background
Reactive oxygen species (ROS) trigger different morphogenic processes in filamentous fungi and have been shown to play a role in the regulation of the biosynthesis of some secondary metabolites. Some bZIP transcription factors, such as Yap1, AtfA and AtfB, mediate resistance to oxidative stress and have a role in secondary metabolism regulation. In this work we aimed to get insight into the molecular basis of this regulation in the industrially important fungus Penicillium chrysogenum through the characterization of the role played by two effectors that mediate the oxidative stress response in development and secondary metabolism.
Results
In P. chrysogenum, penicillin biosynthesis and conidiation are stimulated by the addition of H2O2 to the culture medium, and this effect is mediated by the bZIP transcription factors PcYap1 and PcRsmA. Silencing of expression of both proteins by RNAi resulted in similar phenotypes, characterized by increased levels of ROS in the cell, reduced conidiation, higher sensitivity of conidia to H2O2 and a decrease in penicillin production. Both PcYap1 and PcRsmA are able to sense H2O2-generated ROS in vitro and change its conformation in response to this stimulus. PcYap1 and PcRsmA positively regulate the expression of brlA, the first gene of the conidiation central regulatory pathway. PcYap1 binds in vitro to a previously identified regulatory sequence in the promoter of the penicillin gene pcbAB: TTAGTAA, and to a TTACTAA sequence in the promoter of the brlA gene, whereas PcRsmA binds to the sequences TGAGACA and TTACGTAA (CRE motif) in the promoters of the pcbAB and penDE genes, respectively.
Conclusions
bZIP transcription factors PcYap1 and PcRsmA respond to the presence of H2O2-generated ROS and regulate oxidative stress response in the cell. Both proteins mediate ROS regulation of penicillin biosynthesis and conidiation by binding to specific regulatory elements in the promoters of key genes. PcYap1 is identified as the previously proposed transcription factor PTA1 (Penicillin Transcriptional Activator 1), which binds to the regulatory sequence TTAGTAA in the pcbAB gene promoter. This is the first report of a Yap1 protein directly regulating transcription of a secondary metabolism gene. A model describing the regulatory network mediated by PcYap1 and PcRsmA is proposed.
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17
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Systematic Characterization of bZIP Transcription Factors Required for Development and Aflatoxin Generation by High-Throughput Gene Knockout in Aspergillus flavus. J Fungi (Basel) 2022; 8:jof8040356. [PMID: 35448587 PMCID: PMC9031554 DOI: 10.3390/jof8040356] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/23/2022] [Accepted: 03/23/2022] [Indexed: 12/31/2022] Open
Abstract
The basic leucine zipper (bZIP) is an important transcription factor required for fungal development, nutrient utilization, biosynthesis of secondary metabolites, and defense against various stresses. Aspergillus flavus is a major producer of aflatoxin and an opportunistic fungus on a wide range of hosts. However, little is known about the role of most bZIP genes in A. flavus. In this study, we developed a high-throughput gene knockout method based on an Agrobacterium-mediated transformation system. Gene knockout construction by yeast recombinational cloning and screening of the null mutants by double fluorescence provides an efficient way to construct gene-deleted mutants for this multinucleate fungus. We deleted 15 bZIP genes in A. flavus. Twelve of these genes were identified and characterized in this strain for the first time. The phenotypic analysis of these mutants showed that the 15 bZIP genes play a diverse role in mycelial growth (eight genes), conidiation (13 genes), aflatoxin biosynthesis (10 genes), oxidative stress response (11 genes), cell wall stress (five genes), osmotic stress (three genes), acid and alkali stress (four genes), and virulence to kernels (nine genes). Impressively, all 15 genes were involved in the development of sclerotia, and the respective deletion mutants of five of them did not produce sclerotia. Moreover, MetR was involved in this biological process. In addition, HapX and MetR play important roles in the adaptation to excessive iron and sulfur metabolism, respectively. These studies provide comprehensive insights into the role of bZIP transcription factors in this aflatoxigenic fungus of global significance.
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18
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Fierro F, Vaca I, Castillo NI, García-Rico RO, Chávez R. Penicillium chrysogenum, a Vintage Model with a Cutting-Edge Profile in Biotechnology. Microorganisms 2022; 10:microorganisms10030573. [PMID: 35336148 PMCID: PMC8954384 DOI: 10.3390/microorganisms10030573] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/15/2022] [Accepted: 02/17/2022] [Indexed: 12/20/2022] Open
Abstract
The discovery of penicillin entailed a decisive breakthrough in medicine. No other medical advance has ever had the same impact in the clinical practise. The fungus Penicillium chrysogenum (reclassified as P. rubens) has been used for industrial production of penicillin ever since the forties of the past century; industrial biotechnology developed hand in hand with it, and currently P. chrysogenum is a thoroughly studied model for secondary metabolite production and regulation. In addition to its role as penicillin producer, recent synthetic biology advances have put P. chrysogenum on the path to become a cell factory for the production of metabolites with biotechnological interest. In this review, we tell the history of P. chrysogenum, from the discovery of penicillin and the first isolation of strains with high production capacity to the most recent research advances with the fungus. We will describe how classical strain improvement programs achieved the goal of increasing production and how the development of different molecular tools allowed further improvements. The discovery of the penicillin gene cluster, the origin of the penicillin genes, the regulation of penicillin production, and a compilation of other P. chrysogenum secondary metabolites will also be covered and updated in this work.
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Affiliation(s)
- Francisco Fierro
- Departamento de Biotecnología, Universidad Autónoma Metropolitana-Unidad Iztapalapa, Ciudad de México 09340, Mexico
- Correspondence:
| | - Inmaculada Vaca
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile;
| | - Nancy I. Castillo
- Grupo de Investigación en Ciencias Biológicas y Químicas, Facultad de Ciencias, Universidad Antonio Nariño, Bogotá 110231, Colombia;
| | - Ramón Ovidio García-Rico
- Grupo de Investigación GIMBIO, Departamento De Microbiología, Facultad de Ciencias Básicas, Universidad de Pamplona, Pamplona 543050, Colombia;
| | - Renato Chávez
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9170020, Chile;
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19
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Jia K, Yan L, Jia Y, Xu S, Yan Z, Wang S. aflN Is Involved in the Biosynthesis of Aflatoxin and Conidiation in Aspergillus flavus. Toxins (Basel) 2021; 13:toxins13110831. [PMID: 34822615 PMCID: PMC8617700 DOI: 10.3390/toxins13110831] [Citation(s) in RCA: 4] [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: 10/24/2021] [Revised: 11/17/2021] [Accepted: 11/20/2021] [Indexed: 01/08/2023] Open
Abstract
Aspergillus flavus poses a threat to society economy and public health due to aflatoxin production. aflN is a gene located in the aflatoxin gene cluster, but the function of AflN is undefined in Aspergillus flavus. In this study, aflN is knocked out and overexpressed to study the function of AflN. The results indicated that the loss of AflN leads to the defect of aflatoxin biosynthesis. AflN is also found to play a role in conidiation but not hyphal growth and sclerotia development. Moreover, AlfN is related to the response to environmental oxidative stress and intracellular levels of reactive oxygen species. At last, AflN is involved in the pathogenicity of Aspergillus flavus to host. These results suggested that AflN played important roles in aflatoxin biosynthesis, conidiation and reactive oxygen species generation in Aspergillus flavus, which will be helpful for the understanding of aflN function, and will be beneficial to the prevention and control of Aspergillus flavus and aflatoxins contamination.
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20
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Bákány B, Yin WB, Dienes B, Nagy T, Leiter É, Emri T, Keller NP, Pócsi I. Study on the bZIP-Type Transcription Factors NapA and RsmA in the Regulation of Intracellular Reactive Species Levels and Sterigmatocystin Production of Aspergillus nidulans. Int J Mol Sci 2021; 22:11577. [PMID: 34769008 PMCID: PMC8583795 DOI: 10.3390/ijms222111577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/20/2021] [Accepted: 10/22/2021] [Indexed: 11/16/2022] Open
Abstract
Basic leucine zipper (bZIP) transcription factors play a crucial role in the environmental stress response of eukaryotes. In this work, we studied the effect of gene manipulations, including both deletions and overexpressions, of two selected bZIP transcription factors, NapA and RsmA, in the oxidative stress response and sterigmatocystin production of Aspergillus nidulans. We found that NapA was important in the oxidative stress response by negatively regulating intracellular reactive species production and positively regulating catalase activities, whereas RsmA slightly negatively regulated catalase activities. Concerning sterigmatocystin production, the highest concentration was measured in the ΔrsmAΔnapA double deletion mutant, but elevated sterigmatocystin production was also found in the OErsmA OEnapA strain. Our results indicate that NapA influences sterigmatocystin production via regulating reactive species level whereas RsmA modulates toxin production independently of the redox regulation of the cells.
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Affiliation(s)
- Bernadett Bákány
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary; (B.B.); (T.E.); (I.P.)
- Doctoral School of Molecular Medicine, University of Debrecen, H-4010 Debrecen, Hungary
- Institute of Physiology, Faculty of Medicine, University of Debrecen, H-4010 Debrecen, Hungary;
| | - Wen-Bing Yin
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China;
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA;
| | - Beatrix Dienes
- Institute of Physiology, Faculty of Medicine, University of Debrecen, H-4010 Debrecen, Hungary;
| | - Tibor Nagy
- Department of Applied Chemistry, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary;
| | - Éva Leiter
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary; (B.B.); (T.E.); (I.P.)
| | - Tamás Emri
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary; (B.B.); (T.E.); (I.P.)
| | - Nancy P. Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA;
- Department of Bacteriology, University of Wisconsin, Madison, WI 53706, USA
| | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary; (B.B.); (T.E.); (I.P.)
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21
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Glyap1 regulates pneumocandin B 0 synthesis by controlling the intracellular redox balance in Glarea lozoyensis. Appl Microbiol Biotechnol 2021; 105:6707-6718. [PMID: 34476516 DOI: 10.1007/s00253-021-11522-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/02/2021] [Accepted: 08/05/2021] [Indexed: 10/20/2022]
Abstract
Pneumocandin B0, the precursor of the antifungal drug caspofungin, is a lipohexapeptide produced by the fungus Glarea lozoyensis. Oxidative stress and the resulting production of reactive oxygen species (ROS) are known to be involved in the regulation of pneumocandin B0 biosynthesis. In this study, the Glyap1 gene of Glarea lozoyensis, a homologue of the yeast redox regulator YAP1, was knocked out. The intracellular ROS levels of the resulting ΔGlyap1 strain were higher than in the wild-type strain, which was caused by the downregulated expression of superoxide dismutase (SOD) and catalase (CAT). Compared with the wild-type strain, ΔGlyap1 exhibited an oxidative phenotype throughout its life cycle, which resulted in significantly higher pneumocandin B0 production per unit biomass. In addition, ΔGlyap1 showed growth inhibition and decreased pneumocandin B0 production in the presence of CCl4, which leads to strong oxidative stress. To overcome the strain's sensitivity, a three-stage antioxidant addition strategy was developed. This approach significantly improved the growth of ΔGlyap1 while maintaining a high pneumocandin B0 production per unit biomass, which reached 38.78 mg/g DCW. Notably, this result represents a 50% increase over the wild-type strain. These findings provide new insights into the regulatory mechanisms that control pneumocandin B0 production under oxidative stress, which may be applied to improve the production of other secondary metabolites. KEY POINTS: • Glyap1 is involved in expression of redox and pneumocandin B0 synthesis-related genes. • Addition of a three-stage antioxidant alleviated the sensitivity of ΔGlyap1 strain. • The yield of pneumocandin B0 per unit biomass of ΔGlyap1 strain was 38.78 mg/g DCW.
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22
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Leiter É, Emri T, Pákozdi K, Hornok L, Pócsi I. The impact of bZIP Atf1ortholog global regulators in fungi. Appl Microbiol Biotechnol 2021; 105:5769-5783. [PMID: 34302199 PMCID: PMC8390427 DOI: 10.1007/s00253-021-11431-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/22/2021] [Accepted: 06/24/2021] [Indexed: 11/09/2022]
Abstract
Regulation of signal transduction pathways is crucial for the maintenance of cellular homeostasis and organismal development in fungi. Transcription factors are key elements of this regulatory network. The basic-region leucine zipper (bZIP) domain of the bZIP-type transcription factors is responsible for DNA binding while their leucine zipper structural motifs are suitable for dimerization with each other facilitiating the formation of homodimeric or heterodimeric bZIP proteins. This review highlights recent knowledge on the function of fungal orthologs of the Schizosaccharomyces pombe Atf1, Aspergillus nidulans AtfA, and Fusarium verticillioides FvAtfA, bZIP-type transcription factors with a special focus on pathogenic species. We demonstrate that fungal Atf1-AtfA-FvAtfA orthologs play an important role in vegetative growth, sexual and asexual development, stress response, secondary metabolite production, and virulence both in human pathogens, including Aspergillus fumigatus, Mucor circinelloides, Penicillium marneffei, and Cryptococcus neoformans and plant pathogens, like Fusarium ssp., Magnaporthe oryzae, Claviceps purpurea, Botrytis cinerea, and Verticillium dahliae. KEY POINTS: • Atf1 orthologs play crucial role in the growth and development of fungi. • Atf1 orthologs orchestrate environmental stress response of fungi. • Secondary metabolite production and virulence are coordinated by Atf1 orthologs.
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Affiliation(s)
- Éva Leiter
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, University of Debrecen, P.O. Box 63, Debrecen, H-4010, Hungary.
| | - Tamás Emri
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, University of Debrecen, P.O. Box 63, Debrecen, H-4010, Hungary
| | - Klaudia Pákozdi
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, University of Debrecen, P.O. Box 63, Debrecen, H-4010, Hungary
| | - László Hornok
- Hungarian University of Agriculture and Life Sciences, Gödöllő, Hungary
| | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, University of Debrecen, P.O. Box 63, Debrecen, H-4010, Hungary
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23
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Aflatoxin Biosynthesis, Genetic Regulation, Toxicity, and Control Strategies: A Review. J Fungi (Basel) 2021; 7:jof7080606. [PMID: 34436145 PMCID: PMC8397101 DOI: 10.3390/jof7080606] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/19/2021] [Accepted: 07/22/2021] [Indexed: 12/24/2022] Open
Abstract
Aflatoxins (AFs) are highly toxic and cancer-causing compounds, predominantly synthesized by the Aspergillus species. AFs biosynthesis is a lengthy process that requires as minimum as 30 genes grouped inside 75 kilobytes (kB) of gene clusters, which are regulated by specific transcription factors, including aflR, aflS, and some general transcription factors. This paper summarizes the status of research on characterizing structural and regulatory genes associated with AF production and their roles in aflatoxigenic fungi, particularly Aspergillus flavus and A. parasiticus, and enhances the current understanding of AFs that adversely affect humans and animals with a great emphasis on toxicity and preventive methods.
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Hernandez C, Cadenillas L, Maghubi AE, Caceres I, Durrieu V, Mathieu C, Bailly JD. Mimosa tenuiflora Aqueous Extract: Role of Condensed Tannins in Anti-Aflatoxin B1 Activity in Aspergillus flavus. Toxins (Basel) 2021; 13:toxins13060391. [PMID: 34072350 PMCID: PMC8228179 DOI: 10.3390/toxins13060391] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/25/2021] [Accepted: 05/27/2021] [Indexed: 02/07/2023] Open
Abstract
Aflatoxin B1 (AFB1) is a potent carcinogenic mycotoxin that contaminates numerous crops pre- and post-harvest. To protect foods and feeds from such toxins without resorting to pesticides, the use of plant extracts has been increasingly studied. The most interesting candidate plants are those with strong antioxidative activity because oxidation reactions may interfere with AFB1 production. The present study investigates how an aqueous extract of Mimosa tenuiflora bark affects both the growth of Aspergillus flavus and AFB1 production. The results reveal a dose-dependent inhibition of toxin synthesis with no impact on fungal growth. AFB1 inhibition is related to a down-modulation of the cluster genes of the biosynthetic pathway and especially to the two internal regulators aflR and aflS. Its strong anti-oxidative activity also allows the aqueous extract to modulate the expression of genes involved in fungal oxidative-stress response, such as msnA, mtfA, atfA, or sod1. Finally, a bio-guided fractionation of the aqueous extract demonstrates that condensed tannins play a major role in the anti-aflatoxin activity of Mimosa tenuiflora bark.
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Affiliation(s)
- Christopher Hernandez
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRAE, ENVT, EI-Purpan, 313000 Toulouse, France; (C.H.); (L.C.); (A.E.M.); (I.C.)
- Laboratoire de Chimie Agro-Industrielle (LCA), Université de Toulouse, INRA, INPT, 4 Allée Emile Monso, 31030 Toulouse, France; (V.D.); (C.M.)
| | - Laura Cadenillas
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRAE, ENVT, EI-Purpan, 313000 Toulouse, France; (C.H.); (L.C.); (A.E.M.); (I.C.)
- Laboratoire de Chimie Agro-Industrielle (LCA), Université de Toulouse, INRA, INPT, 4 Allée Emile Monso, 31030 Toulouse, France; (V.D.); (C.M.)
| | - Anwar El Maghubi
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRAE, ENVT, EI-Purpan, 313000 Toulouse, France; (C.H.); (L.C.); (A.E.M.); (I.C.)
| | - Isaura Caceres
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRAE, ENVT, EI-Purpan, 313000 Toulouse, France; (C.H.); (L.C.); (A.E.M.); (I.C.)
| | - Vanessa Durrieu
- Laboratoire de Chimie Agro-Industrielle (LCA), Université de Toulouse, INRA, INPT, 4 Allée Emile Monso, 31030 Toulouse, France; (V.D.); (C.M.)
| | - Céline Mathieu
- Laboratoire de Chimie Agro-Industrielle (LCA), Université de Toulouse, INRA, INPT, 4 Allée Emile Monso, 31030 Toulouse, France; (V.D.); (C.M.)
- Centre d’Application et de Traitement des Agro-Ressources (CATAR), INPT, Toulouse, 4 Allée Emile Monso, 31030 Toulouse, France
| | - Jean-Denis Bailly
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRAE, ENVT, EI-Purpan, 313000 Toulouse, France; (C.H.); (L.C.); (A.E.M.); (I.C.)
- Correspondence: ; Tel.: +33-56-1193-229
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Singh Y, Nair AM, Verma PK. Surviving the odds: From perception to survival of fungal phytopathogens under host-generated oxidative burst. PLANT COMMUNICATIONS 2021; 2:100142. [PMID: 34027389 PMCID: PMC8132124 DOI: 10.1016/j.xplc.2021.100142] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/04/2020] [Accepted: 01/01/2021] [Indexed: 05/04/2023]
Abstract
Fungal phytopathogens pose a serious threat to global crop production. Only a handful of strategies are available to combat these fungal infections, and the increasing incidence of fungicide resistance is making the situation worse. Hence, the molecular understanding of plant-fungus interactions remains a primary focus of plant pathology. One of the hallmarks of host-pathogen interactions is the overproduction of reactive oxygen species (ROS) as a plant defense mechanism, collectively termed the oxidative burst. In general, high accumulation of ROS restricts the growth of pathogenic organisms by causing localized cell death around the site of infection. To survive the oxidative burst and achieve successful host colonization, fungal phytopathogens employ intricate mechanisms for ROS perception, ROS neutralization, and protection from ROS-mediated damage. Together, these countermeasures maintain the physiological redox homeostasis that is essential for cell viability. In addition to intracellular antioxidant systems, phytopathogenic fungi also deploy interesting effector-mediated mechanisms for extracellular ROS modulation. This aspect of plant-pathogen interactions is significantly under-studied and provides enormous scope for future research. These adaptive responses, broadly categorized into "escape" and "exploitation" mechanisms, are poorly understood. In this review, we discuss the oxidative stress response of filamentous fungi, their perception signaling, and recent insights that provide a comprehensive understanding of the distinct survival mechanisms of fungal pathogens in response to the host-generated oxidative burst.
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Affiliation(s)
- Yeshveer Singh
- Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Athira Mohandas Nair
- Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Praveen Kumar Verma
- Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
- Corresponding author
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Hu Z, Yuan K, Zhou Q, Lu C, Du L, Liu F. Mechanism of antifungal activity of Perilla frutescens essential oil against Aspergillus flavus by transcriptomic analysis. Food Control 2021. [DOI: 10.1016/j.foodcont.2020.107703] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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The DUG Pathway Governs Degradation of Intracellular Glutathione in Aspergillus nidulans. Appl Environ Microbiol 2021; 87:AEM.01321-20. [PMID: 33637571 DOI: 10.1128/aem.01321-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 02/10/2021] [Indexed: 12/27/2022] Open
Abstract
Glutathione (GSH) is an abundant tripeptide that plays a crucial role in shielding cellular macromolecules from various reactive oxygen and nitrogen species in fungi. Understanding GSH metabolism is of vital importance for deciphering redox regulation in these microorganisms. In the present study, to better understand the GSH metabolism in filamentous fungi, we investigated functions of the dugB and dugC genes in the model fungus Aspergillus nidulans These genes are orthologues of dug2 and dug3, which are involved in cytosolic GSH degradation in Saccharomyces cerevisiae The deletion of dugB, dugC, or both resulted in a moderate increase in the GSH content in mycelia grown on glucose, reduced conidium production, and disturbed sexual development. In agreement with these observations, transcriptome data showed that genes encoding mitogen-activated protein (MAP) kinase pathway elements (e.g., steC, sskB, hogA, and mkkA) or regulatory proteins of conidiogenesis and sexual differentiation (e.g., flbA, flbC, flbE, nosA, rosA, nsdC, and nsdD) were downregulated in the ΔdugB ΔdugC mutant. Deletion of dugB and/or dugC slowed the depletion of GSH pools during carbon starvation. It also reduced accumulation of reactive oxygen species and decreased autolytic cell wall degradation and enzyme secretion but increased sterigmatocystin formation. Transcriptome data demonstrated that enzyme secretions-in contrast to mycotoxin production-were controlled at the posttranscriptional level. We suggest that GSH connects starvation and redox regulation to each other: cells utilize GSH as a stored carbon source during starvation. The reduction of GSH content alters the redox state, activating regulatory pathways responsible for carbon starvation stress responses.IMPORTANCE Glutathione (GSH) is a widely distributed tripeptide in both eukaryotes and prokaryotes. Owing to its very low redox potential, antioxidative character, and high intracellular concentration, GSH profoundly shapes the redox status of cells. Our observations suggest that GSH metabolism and/or the redox status of cells plays a determinative role in several important aspects of fungal life, including oxidative stress defense, protein secretion, and secondary metabolite production (including mycotoxin formation), as well as sexual and asexual differentiations. We demonstrated that even a slightly elevated GSH level can substantially disturb the homeostasis of fungi. This information could be important for development of new GSH-producing strains or for any biotechnologically relevant processes where the GSH content, antioxidant capacity, or oxidative stress tolerance of a fungal strain is manipulated.
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Physical and Chemical Methods for Reduction in Aflatoxin Content of Feed and Food. Toxins (Basel) 2021; 13:toxins13030204. [PMID: 33808964 PMCID: PMC7999035 DOI: 10.3390/toxins13030204] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 12/25/2022] Open
Abstract
Aflatoxins (AFs) are among the most harmful fungal secondary metabolites imposing serious health risks on both household animals and humans. The more frequent occurrence of aflatoxins in the feed and food chain is clearly foreseeable as a consequence of the extreme weather conditions recorded most recently worldwide. Furthermore, production parameters, such as unadjusted variety use and improper cultural practices, can also increase the incidence of contamination. In current aflatoxin control measures, emphasis is put on prevention including a plethora of pre-harvest methods, introduced to control Aspergillus infestations and to avoid the deleterious effects of aflatoxins on public health. Nevertheless, the continuous evaluation and improvement of post-harvest methods to combat these hazardous secondary metabolites are also required. Already in-use and emerging physical methods, such as pulsed electric fields and other nonthermal treatments as well as interventions with chemical agents such as acids, enzymes, gases, and absorbents in animal husbandry have been demonstrated as effective in reducing mycotoxins in feed and food. Although most of them have no disadvantageous effect either on nutritional properties or food safety, further research is needed to ensure the expected efficacy. Nevertheless, we can envisage the rapid spread of these easy-to-use, cost-effective, and safe post-harvest tools during storage and food processing.
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The inhibitory mechanism of methyl jasmonate on Aspergillus flavus growth and aflatoxin biosynthesis and two novel transcription factors are involved in this action. Food Res Int 2021; 140:110051. [DOI: 10.1016/j.foodres.2020.110051] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/13/2020] [Accepted: 12/16/2020] [Indexed: 11/22/2022]
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The Potential of Plant-Based Bioactive Compounds on Inhibition of Aflatoxin B1 Biosynthesis and Down-regulation of aflR, aflM and aflP Genes. Antibiotics (Basel) 2020; 9:antibiotics9110728. [PMID: 33113979 PMCID: PMC7690750 DOI: 10.3390/antibiotics9110728] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/12/2020] [Accepted: 10/21/2020] [Indexed: 01/11/2023] Open
Abstract
The use of plant extracts in pre- and post-harvest disease management of agricultural crops to cope with aflatoxin B1 contamination has shown great promise due to their capability in managing toxins and safe-keeping the quality. We investigated the anti-aflatoxigenic effect of multiple doses of eight plant extracts (Heracleum persicum, Peganum harmala, Crocus sativus, Trachyspermum ammi, Rosmarinus officinalis, Anethum graveolens, Berberis vulgaris, Berberis thunbergii) on Aspergillus flavus via LC-MS and the down-regulatory effect of them on aflR, aflM and aflP genes involved in the aflatoxin B1 biosynthesis pathway using RT-qPCR analyses. Our results showed that H. persicum (4 mg/mL), P. harmala (6 mg/mL) and T. ammi (2 mg/mL) completely stopped the production of aflatoxin B1, without inducing significant changes in A. flavus growth. Furthermore, our findings showed a highly significant correlation between the gene expression and the aflatoxin B1 biosynthesis, such that certain doses of the extracts reduced or blocked the expression of the aflR, aflM and aflP and consequently reduced the synthesis of aflatoxin B1. Interestingly, compared to the regulatory gene (aflR), the down-regulation of expression in the structural genes (aflM and aflP) was more consistent and correlated with the inhibition of aflatoxin B1 production. Overall, this study reveals the anti-aflatoxigenic mechanisms of the selected plant extracts at the gene expression level and provides evidence for their use in plant and crop protection.
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Barrios-González J, Pérez-Sánchez A, Bibián ME. New knowledge about the biosynthesis of lovastatin and its production by fermentation of Aspergillus terreus. Appl Microbiol Biotechnol 2020; 104:8979-8998. [PMID: 32930839 DOI: 10.1007/s00253-020-10871-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 08/10/2020] [Accepted: 08/31/2020] [Indexed: 12/21/2022]
Abstract
Lovastatin, and its semisynthetic derivative simvastatine, has great medical and economic importance, besides great potential for other uses. In the last years, a deeper and more complex view of secondary metabolism regulation has emerged, with the incorporation of cluster-specific and global transcription factors, and their relation to signaling cascades, as well as the new level of epigenetic regulation. Recently, a new mechanism, which regulates lovastatin biosynthesis, at transcriptional level, has been discovered: reactive oxygen species (ROS) regulation; also new unexpected environmental stimuli have been identified, which induce the synthesis of lovastatin, like quorum sensing-type molecules and support stimuli. The present review describes this new panorama and uses this information, together with the knowledge on lovastatin biosynthesis and genomics, as the foundation to analyze literature on optimization of fermentation parameters and medium composition, and also to fully understand new strategies for strain genetic improvement. This new knowledge has been applied to the development of more effective culture media, with the addition of molecules like butyrolactone I, oxylipins, and spermidine, or with addition of ROS-generating molecules to increase internal ROS levels in the cell. It has also been applied to the development of new strategies to generate overproducing strains of Aspergillus terreus, including engineering of the cluster-specific transcription factor (lovE), global transcription factors like the ones implicated in ROS regulation (or even mitochondrial alternative respiration aox gen), or the global regulator LaeA. Moreover, there is potential to apply some of these findings to the development of novel unconventional production systems. KEY POINTS: • New findings in regulation of lovastatin biosynthesis, like ROS regulation. • Induction by unexpected stimuli: autoinducer molecules and support stimuli. • Recent reports on culture medium and process optimization from this stand point. • Applications to molecular genetic strain improvement methods and production systems.
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Affiliation(s)
- Javier Barrios-González
- Departamento de Biotecnología, Universidad Autónoma Metropolitana -Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340, Iztapalapa, Ciudad de México, Mexico.
| | - Ailed Pérez-Sánchez
- Departamento de Biotecnología, Universidad Autónoma Metropolitana -Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340, Iztapalapa, Ciudad de México, Mexico
| | - María Esmeralda Bibián
- Departamento de Biotecnología, Universidad Autónoma Metropolitana -Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340, Iztapalapa, Ciudad de México, Mexico
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Analysis of TabZIP15 transcription factor from Trichoderma asperellum ACCC30536 and its function under pathogenic toxin stress. Sci Rep 2020; 10:15084. [PMID: 32934312 PMCID: PMC7493895 DOI: 10.1038/s41598-020-72226-w] [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: 02/02/2020] [Accepted: 08/27/2020] [Indexed: 11/09/2022] Open
Abstract
The TabZIP15 gene encoding a 396 amino acid (aa) polypeptide in the fungus Trichoderma asperellum ACCC30536 was cloned and characterised. The protein includes a basic region motif (NR-x2-QR-x2-R) and has a pillar-like structure. The 25 basic region/leucine zipper transcription factors (TFs) identified in the T. asperellum genome were divided into YAP (14 TFs), ATF2 (5), GCN4 (2), Zip1 (2), BRLZ (1) and u1 (1) subfamilies based on conserved domains. T. asperellum was cultured in minimal media (MM) control, C-Hungry and N-Hungry medium (to simulate nutrient competition and interaction with pathogens, respectively), and differential expression analysis showed that 14 TabZIP genes (including TabZIP15) were significantly altered under both conditions; TabZIP23 responded strongly to N-Hungry media and TabZIP24 responded strongly to C-Hungry media. However, only YAP genes TabZIP15, TabZIP12 and TabZIP2 were significantly upregulated under both conditions, and expression levels of TabZIP15 were highest. T. asperellum was also cultured in the presence of five fungal pathogenic toxins, and RT-qPCR results showed that TabZIP15 was significantly upregulated in four of the five toxin stress conditions (MM + Rhizoctonia solani, MM + Fusarium oxysporum, MM + Alternaria alternata and MM + Cytospora chrysosperma).
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Li X, Jiang Y, Ma L, Ma X, Liu Y, Shan J, Ma K, Xing F. Comprehensive Transcriptome and Proteome Analyses Reveal the Modulation of Aflatoxin Production by Aspergillus flavus on Different Crop Substrates. Front Microbiol 2020; 11:1497. [PMID: 32760360 PMCID: PMC7371938 DOI: 10.3389/fmicb.2020.01497] [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: 01/08/2020] [Accepted: 06/09/2020] [Indexed: 01/26/2023] Open
Abstract
As a natural severe contaminant of stored grains and other crops worldwide, Aspergillus flavus can produce aflatoxins (AFs), the most powerful naturally producing toxic and hepatocarcinogenic compounds. AFs production is regulated by diverse factors including AFs cluster genes, transcription factors, regulators, and environmental factors. Among them, crop substrate is one of the most important factors. Here, we found that AFB1 production was significantly higher in maize and rice broth than in peanut broth. To clarify the mechanisms involved, complementary transcriptomic and proteomic analyses were performed to identify changes in A. flavus incubated in the three crop substrates. The results indicated that fewer genes and proteins were differentially expressed between maize and rice substrates, whereas more differentially expressed genes were observed between maize/rice broth and peanut broth. In particular, the genes involved in the initial step of AFs biosynthesis (aflA, aflB, and aflC) and the ACCase-encoding gene accA were significantly upregulated on the maize and rice substrates. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses indicated that carbon-metabolism-related genes were obviously enriched in the maize broth, and the genes involved in acetyl-CoA accumulation and consumption were up- and downregulated, respectively. Several genes involved in the regulation of AFs biosynthesis, including veA, ppoB, snf1, and the G-protein-coupled receptor (GPCR) genes, were differentially expressed on the three substrates, suggesting that these genes may be also involved in sugar signal sensing, transfer, and regulation. Interestingly, by the correlation analyses of transcriptome and proteome, trehalose metabolism genes, aldehyde dehydrogenase gene, and tryptophan synthase gene were found to be relevant with the regulation of AFs production on different crop substrates. Taken together, the differential expressions of the AFs cluster genes, several regulatory genes, and carbon metabolism genes were involved in the comprehensive modulation of AFs production on different crop substrates.
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Affiliation(s)
- Xu Li
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yiran Jiang
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Longxue Ma
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaoyun Ma
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yang Liu
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China.,School of Food Science and Engineering, Foshan University, Foshan, China
| | - Jihao Shan
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Kang Ma
- Division of Chemical Metrology and Analytical Science, National Institute of Metrology, Beijing, China
| | - Fuguo Xing
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
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Szabó Z, Pákozdi K, Murvai K, Pusztahelyi T, Kecskeméti Á, Gáspár A, Logrieco AF, Emri T, Ádám AL, Leiter É, Hornok L, Pócsi I. FvatfA regulates growth, stress tolerance as well as mycotoxin and pigment productions in Fusarium verticillioides. Appl Microbiol Biotechnol 2020; 104:7879-7899. [PMID: 32719911 PMCID: PMC7447684 DOI: 10.1007/s00253-020-10717-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/22/2020] [Accepted: 06/01/2020] [Indexed: 01/22/2023]
Abstract
FvatfA from the maize pathogen Fusarium verticillioides putatively encodes the Aspergillus nidulans AtfA and Schizasaccharomyces pombe Atf1 orthologous bZIP-type transcription factor, FvAtfA. In this study, a ΔFvatfA deletion mutant was constructed and then genetically complemented with the fully functional FvatfA gene. Comparing phenotypic features of the wild-type parental, the deletion mutant and the restored strains shed light on the versatile regulatory functions played by FvAtfA in (i) the maintenance of vegetative growth on Czapek-Dox and Potato Dextrose agars and invasive growth on unwounded tomato fruits, (ii) the preservation of conidiospore yield and size, (iii) the orchestration of oxidative (H2O2, menadione sodium bisulphite) and cell wall integrity (Congo Red) stress defences and (iv) the regulation of mycotoxin (fumonisins) and pigment (bikaverin, carotenoid) productions. Expression of selected biosynthetic genes both in the fumonisin (fum1, fum8) and the carotenoid (carRA, carB) pathways were down-regulated in the ΔFvatfA strain resulting in defected fumonisin production and considerably decreased carotenoid yields. The expression of bik1, encoding the polyketide synthase needed in bikaverin biosynthesis, was not up-regulated by the deletion of FvatfA meanwhile the ΔFvatfA strain produced approximately ten times more bikaverin than the wild-type or the genetically complemented strains. The abolishment of fumonisin production of the ΔFvatfA strain may lead to the development of new-type, biology-based mycotoxin control strategies. The novel information gained on the regulation of pigment production by this fungus can be interesting for experts working on new, Fusarium-based biomass and pigment production technologies.Key points • FvatfA regulates vegetative and invasive growths of F. verticillioides. • FvatfA also orchestrates oxidative and cell wall integrity stress defenses. • The ΔFvatfA mutant was deficient in fumonisin production. • FvatfA deletion resulted in decreased carotenoid and increased bikaverin yields. |
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Affiliation(s)
- Zsuzsa Szabó
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary.,Doctoral School of Biological Sciences, Faculty of Agricultural and Environmental Sciences, Szent István University, Gödöllő, Hungary
| | - Klaudia Pákozdi
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary.,Doctoral School of Nutrition and Food Sciences, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Katalin Murvai
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Tünde Pusztahelyi
- Central Laboratory of Agricultural and Food Products, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary
| | - Ádám Kecskeméti
- Department of Inorganic and Analytical Chemistry, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Attila Gáspár
- Department of Inorganic and Analytical Chemistry, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | | | - Tamás Emri
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Attila L Ádám
- Plant Protection Institute, Centre for Agricultural Research, Budapest, Hungary
| | - Éva Leiter
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - László Hornok
- Faculty of Agricultural and Environmental Sciences, Szent István University, Gödöllő, Hungary
| | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary.
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The bZIP Transcription Factor AflRsmA Regulates Aflatoxin B 1 Biosynthesis, Oxidative Stress Response and Sclerotium Formation in Aspergillus flavus. Toxins (Basel) 2020; 12:toxins12040271. [PMID: 32340099 PMCID: PMC7232220 DOI: 10.3390/toxins12040271] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/04/2020] [Accepted: 04/17/2020] [Indexed: 12/29/2022] Open
Abstract
Fungal secondary metabolites play important roles not only in fungal ecology but also in humans living as beneficial medicine or harmful toxins. In filamentous fungi, bZIP-type transcription factors (TFs) are associated with the proteins involved in oxidative stress response and secondary metabolism. In this study, a connection between a bZIP TF and oxidative stress induction of secondary metabolism is uncovered in an opportunistic pathogen Aspergillus flavus, which produces carcinogenic and mutagenic aflatoxins. The bZIP transcription factor AflRsmA was identified by a homology research of A. flavus genome with the bZIP protein RsmA, involved in secondary metabolites production in Aspergillusnidulans. The AflrsmA deletion strain (ΔAflrsmA) displayed less sensitivity to the oxidative reagents tert-Butyl hydroperoxide (tBOOH) in comparison with wild type (WT) and AflrsmA overexpression strain (AflrsmAOE), while AflrsmAOE strain increased sensitivity to the oxidative reagents menadione sodium bisulfite (MSB) compared to WT and ΔAflrsmA strains. Without oxidative treatment, aflatoxin B1 (AFB1) production of ΔAflrsmA strains was consistent with that of WT, but AflrsmAOE strain produced more AFB1 than WT; tBOOH and MSB treatment decreased AFB1 production of ΔAflrsmA compared to WT. Besides, relative to WT, ΔAflrsmA strain decreased sclerotia, while AflrsmAOE strain increased sclerotia. The decrease of AFB1 by ΔAflrsmA but increase of AFB1 by AflrsmAOE was on corn. Our results suggest that AFB1 biosynthesis is regulated by AflRsmA by oxidative stress pathways and provide insights into a possible function of AflRsmA in mediating AFB1 biosynthesis response host defense in pathogen A. flavus.
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Zhu Z, Yang M, Bai Y, Ge F, Wang S. Antioxidant-related catalase CTA1 regulates development, aflatoxin biosynthesis, and virulence in pathogenic fungus Aspergillus flavus. Environ Microbiol 2020; 22:2792-2810. [PMID: 32250030 DOI: 10.1111/1462-2920.15011] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/17/2020] [Accepted: 03/31/2020] [Indexed: 11/29/2022]
Abstract
Reactive oxygen species (ROS) induce the synthesis of a myriad of secondary metabolites, including aflatoxins. It raises significant concern as it is a potent environmental contaminant. In Aspergillus flavus., antioxidant enzymes link ROS stress response with coordinated gene regulation of aflatoxin biosynthesis. In this study, we characterized the function of a core component of the antioxidant enzyme catalase (CTA1) of A. flavus. Firstly, we verified the presence of cta1 corresponding protein (CTA1) by Western blot analysis and mass-spectrometry based analysis. Then, the functional study revealed that the growth, sporulation and sclerotia formation significantly increased, while aflatoxins production and virulence were decreased in the cta1 deletion mutant as compared with the WT and complementary strains. Furthermore, the absence of the cta1 gene resulted in a significant rise in the intracellular ROS level, which in turn added to the oxidative stress level of cells. A further quantitative proteomics investigation hinted that in vivo, CTA1 might maintain the ROS level to facilitate the aflatoxin synthesis. All in all, the pleiotropic phenotype of A. flavus CTA1 deletion mutant revealed that the antioxidant system plays a crucial role in fungal development, aflatoxins biosynthesis and virulence.
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Affiliation(s)
- Zhuo Zhu
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Mingkun Yang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Youhuang Bai
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Feng Ge
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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Aflatoxin Biosynthesis and Genetic Regulation: A Review. Toxins (Basel) 2020; 12:toxins12030150. [PMID: 32121226 PMCID: PMC7150809 DOI: 10.3390/toxins12030150] [Citation(s) in RCA: 120] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/27/2020] [Accepted: 02/25/2020] [Indexed: 12/15/2022] Open
Abstract
The study of fungal species evolved radically with the development of molecular techniques and produced new evidence to understand specific fungal mechanisms such as the production of toxic secondary metabolites. Taking advantage of these technologies to improve food safety, the molecular study of toxinogenic species can help elucidate the mechanisms underlying toxin production and enable the development of new effective strategies to control fungal toxicity. Numerous studies have been made on genes involved in aflatoxin B1 (AFB1) production, one of the most hazardous carcinogenic toxins for humans and animals. The current review presents the roles of these different genes and their possible impact on AFB1 production. We focus on the toxinogenic strains Aspergillus flavus and A. parasiticus, primary contaminants and major producers of AFB1 in crops. However, genetic reports on A. nidulans are also included because of the capacity of this fungus to produce sterigmatocystin, the penultimate stable metabolite during AFB1 production. The aim of this review is to provide a general overview of the AFB1 enzymatic biosynthesis pathway and its link with the genes belonging to the AFB1 cluster. It also aims to illustrate the role of global environmental factors on aflatoxin production and the recent data that demonstrate an interconnection between genes regulated by these environmental signals and aflatoxin biosynthetic pathway.
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Pfliegler WP, Pócsi I, Győri Z, Pusztahelyi T. The Aspergilli and Their Mycotoxins: Metabolic Interactions With Plants and the Soil Biota. Front Microbiol 2020; 10:2921. [PMID: 32117074 PMCID: PMC7029702 DOI: 10.3389/fmicb.2019.02921] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 12/04/2019] [Indexed: 01/06/2023] Open
Abstract
Species of the highly diverse fungal genus Aspergillus are well-known agricultural pests, and, most importantly, producers of various mycotoxins threatening food safety worldwide. Mycotoxins are studied predominantly from the perspectives of human and livestock health. Meanwhile, their roles are far less known in nature. However, to understand the factors behind mycotoxin production, the roles of the toxins of Aspergilli must be understood from a complex ecological perspective, taking mold-plant, mold-microbe, and mold-animal interactions into account. The Aspergilli may switch between saprophytic and pathogenic lifestyles, and the production of secondary metabolites, such as mycotoxins, may vary according to these fungal ways of life. Recent studies highlighted the complex ecological network of soil microbiotas determining the niches that Aspergilli can fill in. Interactions with the soil microbiota and soil macro-organisms determine the role of secondary metabolite production to a great extent. While, upon infection of plants, metabolic communication including fungal secondary metabolites like aflatoxins, gliotoxin, patulin, cyclopiazonic acid, and ochratoxin, influences the fate of both the invader and the host. In this review, the role of mycotoxin producing Aspergillus species and their interactions in the ecosystem are discussed. We intend to highlight the complexity of the roles of the main toxic secondary metabolites as well as their fate in natural environments and agriculture, a field that still has important knowledge gaps.
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Affiliation(s)
- Walter P. Pfliegler
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Zoltán Győri
- Institute of Nutrition, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary
| | - Tünde Pusztahelyi
- Central Laboratory of Agricultural and Food Products, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary
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Ren Y, Jin J, Zheng M, Yang Q, Xing F. Ethanol Inhibits Aflatoxin B 1 Biosynthesis in Aspergillus flavus by Up-Regulating Oxidative Stress-Related Genes. Front Microbiol 2020; 10:2946. [PMID: 32010073 PMCID: PMC6978751 DOI: 10.3389/fmicb.2019.02946] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 12/06/2019] [Indexed: 01/04/2023] Open
Abstract
As the most carcinogenic, toxic, and economically costly mycotoxins, aflatoxin B1 (AFB1) is primarily biosynthesized by Aspergillus flavus and Aspergillus parasiticus. Aflatoxin biosynthesis is related to oxidative stress and functions as a second line of defense from excessive reactive oxygen species. Here, we find that ethanol can inhibit fungal growth and AFB1 production by A. flavus in a dose-dependent manner. Then, the ethanol’s molecular mechanism of action on AFB1 biosynthesis was revealed using a comparative transcriptomic analysis. RNA-Seq data indicated that all the genes except for aflC in the aflatoxin gene cluster were down-regulated by 3.5% ethanol. The drastic repression of aflatoxin structural genes including the complete inhibition of aflK and aflLa may be correlated with the down-regulation of the transcription regulator genes aflR and aflS in the cluster. This may be due to the repression of several global regulator genes and the subsequent overexpression of some oxidative stress-related genes. The suppression of several key aflatoxin genes including aflR, aflD, aflM, and aflP may also be associated with the decreased expression of the global regulator gene veA. In particular, ethanol exposure caused the decreased expression of stress response transcription factor srrA and the overexpression of bZIP transcription factor ap-1, C2H2 transcription factors msnA and mtfA, together with the enhanced levels of anti-oxidant enzymatic genes including Cat, Cat1, Cat2, CatA, and Cu, Zn superoxide dismutase gene sod1. Taken together, these RNA-Seq data strongly suggest that ethanol inhibits AFB1 biosynthesis by A. flavus via enhancing fungal oxidative stress response. In conclusion, this study served to reveal the anti-aflatoxigenic mechanisms of ethanol in A. flavus and to provide solid evidence for its use in controlling AFB1 contamination.
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Affiliation(s)
- Yaoyao Ren
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Jing Jin
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Mumin Zheng
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Qingli Yang
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Fuguo Xing
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China.,Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
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Penicillin and cephalosporin biosyntheses are also regulated by reactive oxygen species. Appl Microbiol Biotechnol 2020; 104:1773-1783. [PMID: 31900551 DOI: 10.1007/s00253-019-10330-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 12/10/2019] [Accepted: 12/18/2019] [Indexed: 12/12/2022]
Abstract
In an earlier work on lovastatin production by Aspergillus terreus, we found that reactive oxygen species (ROS) concentration increased to high levels precisely at the start of the production phase (idiophase) and that these levels were sustained during all idiophase. Moreover, it was shown that ROS regulate lovastatin biosynthesis. ROS regulation has also been reported for aflatoxins. It has been suggested that, due to their antioxidant activity, aflatoxins are regulated and synthesized like a second line of defense against oxidative stress. To study the possible ROS regulation of other industrially important secondary metabolites, we analyzed the relationship between ROS and penicillin biosynthesis by Penicillium chrysogenum and cephalosporin biosynthesis by Acremonium chrysogenum. Results revealed a similar ROS accumulation in idiophase in penicillin and cephalosporin fermentations. Moreover, when intracellular ROS concentrations were decreased by the addition of antioxidants to the cultures, penicillin and cephalosporin production were drastically reduced. When intracellular ROS were increased by the addition of exogenous ROS (H2O2) to the cultures, proportional increments in penicillin and cephalosporin biosyntheses were obtained. It was also shown that lovastatin, penicillin, and cephalosporin are not antioxidants. Taken together, our results provide evidence that ROS regulation is a general mechanism controlling secondary metabolism in fungi.
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Guan X, Zhao Y, Liu X, Shang B, Xing F, Zhou L, Wang Y, Zhang C, Bhatnagar D, Liu Y. The bZIP transcription factor Afap1 mediates the oxidative stress response and aflatoxin biosynthesis in Aspergillus flavus. Rev Argent Microbiol 2019; 51:292-301. [DOI: 10.1016/j.ram.2018.07.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/26/2018] [Accepted: 07/15/2018] [Indexed: 11/28/2022] Open
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Wang P, Ma L, Jin J, Zheng M, Pan L, Zhao Y, Sun X, Liu Y, Xing F. The anti-aflatoxigenic mechanism of cinnamaldehyde in Aspergillus flavus. Sci Rep 2019; 9:10499. [PMID: 31324857 PMCID: PMC6642104 DOI: 10.1038/s41598-019-47003-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 07/09/2019] [Indexed: 11/16/2022] Open
Abstract
Aflatoxin B1 (AFB1), the predominant and most carcinogenic naturally polyketide, is mainly produced by Aspergillus flavus and Aspergillus parasiticus. Cinnamaldehyde has been reported for inhibiting the growth and aflatoxin biosynthesis in A. flavus. But its molecular mechanism of action still remains largely ambiguous. Here, the anti-aflatoxigenic mechanism of cinnamaldehyde in A. flavus was investigated via a comparative transcriptomic analysis. The results indicated that twenty five of thirty genes in aflatoxin cluster showed down-regulation by cinnamaldehyde although the cluster regulators aflR and aflS were slightly up-regulated. This may be due to the up-regulation of the oxidative stress-related genes srrA, msnA and atfB being caused by the significant down-regulation of the diffusible factor FluG. Cinnamaldehyde also inhibited aflatoxin formation by perturbing GPCRs and oxylipins normal function, cell wall biosynthesis and redox equilibrium. In addition, accumulation of NADPH due to up-regulation of pentose phosphate pathway drove acetyl-CoA to lipids synthesis rather than polyketides. Both GO and KEGG analysis suggested that pyruvate and phenylalanine metabolism, post-transcriptional modification and key enzymes biosynthesis might be involved in the suppression of AFB1 production by cinnamaldehyde. This study served to decipher the anti-aflatoxigenic properties of cinnamaldehyde in A. flavus and provided powerful evidence for its use in practice.
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Affiliation(s)
- Ping Wang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Longxue Ma
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Jing Jin
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Mumin Zheng
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Lin Pan
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Yueju Zhao
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Xiulan Sun
- State Key Laboratory of Food Science and Technology, School of Food Science, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu, 214122, P.R. China
| | - Yang Liu
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Fuguo Xing
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China.
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Devi MS, Sashidhar RB. Antiaflatoxigenic effects of selected antifungal peptides. Peptides 2019; 115:15-26. [PMID: 30776385 DOI: 10.1016/j.peptides.2019.02.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 02/08/2019] [Accepted: 02/14/2019] [Indexed: 12/11/2022]
Abstract
Aflatoxins are potent carcinogenic mycotoxins produced as secondary metabolites mainly by the fungi Aspergillus flavus and Aspergillus parasiticus. Control measures to curtail the contamination of aflatoxin in food products is still a challenge. Although there are several reports on the antifungal peptides, there is no specific study on the action of antifungal peptides on aflatoxin synthesis. This work details the effect of four antimicrobial peptides (AMPs) - PPD1 (FRLHF), 66-10 (FRLKFH), 77-3 (FRLKFHF) and D4E1 (FKLRAKIKVRLRAKIKL) on the aflatoxin production by A. flavus and A. parasiticus. Results of the investigations suggests that AMPs at near minimum inhibitory concentrations (MIC) were effectively inhibiting aflatoxins, without hindering the growth of the fungi. These AMPs, at concentrations near MIC, induced membrane permeabilisation, without inducing cellular leakage. The involvement of oxidative stress for the aflatoxin synthesis was reversed by the antioxidant nature of the peptides as evidenced by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay, reactive oxygen species production, malondialdehyde and antioxidant enzymes analysis. Quantitative real time polymerase chain reaction (RT-qPCR) analysis of the aflatoxin gene cluster showed that 'aflR' and its downstream genes expressions were significantly down regulated. Conidiation of the fungi were negatively influenced by the peptides as evidenced by scanning electron microscopy analysis and RT-qPCR. mRNA levels of Manganese-superoxide dismutase (Mn-SOD) showed a decrease in the expression in RT-qPCR. The effect of these peptides on aflatoxin inhibition provides insight into their use as novel antiaflatoxigenic molecules.
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Affiliation(s)
- Manju S Devi
- Department of Biochemistry, University College of Science, Osmania University, Hyderabad-500 007, Telangana State, India
| | - R B Sashidhar
- Department of Biochemistry, University College of Science, Osmania University, Hyderabad-500 007, Telangana State, India.
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Ren Y, Jin J, Zheng M, Yang Q, Xing F. Ethanol Inhibits Aflatoxin B 1 Biosynthesis in Aspergillus flavus by Up-Regulating Oxidative Stress-Related Genes. Front Microbiol 2019. [PMID: 32010073 DOI: 10.3389/fmicb.2019.02946/bibtex] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023] Open
Abstract
As the most carcinogenic, toxic, and economically costly mycotoxins, aflatoxin B1 (AFB1) is primarily biosynthesized by Aspergillus flavus and Aspergillus parasiticus. Aflatoxin biosynthesis is related to oxidative stress and functions as a second line of defense from excessive reactive oxygen species. Here, we find that ethanol can inhibit fungal growth and AFB1 production by A. flavus in a dose-dependent manner. Then, the ethanol's molecular mechanism of action on AFB1 biosynthesis was revealed using a comparative transcriptomic analysis. RNA-Seq data indicated that all the genes except for aflC in the aflatoxin gene cluster were down-regulated by 3.5% ethanol. The drastic repression of aflatoxin structural genes including the complete inhibition of aflK and aflLa may be correlated with the down-regulation of the transcription regulator genes aflR and aflS in the cluster. This may be due to the repression of several global regulator genes and the subsequent overexpression of some oxidative stress-related genes. The suppression of several key aflatoxin genes including aflR, aflD, aflM, and aflP may also be associated with the decreased expression of the global regulator gene veA. In particular, ethanol exposure caused the decreased expression of stress response transcription factor srrA and the overexpression of bZIP transcription factor ap-1, C2H2 transcription factors msnA and mtfA, together with the enhanced levels of anti-oxidant enzymatic genes including Cat, Cat1, Cat2, CatA, and Cu, Zn superoxide dismutase gene sod1. Taken together, these RNA-Seq data strongly suggest that ethanol inhibits AFB1 biosynthesis by A. flavus via enhancing fungal oxidative stress response. In conclusion, this study served to reveal the anti-aflatoxigenic mechanisms of ethanol in A. flavus and to provide solid evidence for its use in controlling AFB1 contamination.
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Affiliation(s)
- Yaoyao Ren
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Jing Jin
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Mumin Zheng
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Qingli Yang
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Fuguo Xing
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
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Zhao X, Zhi QQ, Li JY, Keller NP, He ZM. The Antioxidant Gallic Acid Inhibits Aflatoxin Formation in Aspergillus flavus by Modulating Transcription Factors FarB and CreA. Toxins (Basel) 2018; 10:toxins10070270. [PMID: 29970790 PMCID: PMC6071284 DOI: 10.3390/toxins10070270] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 06/23/2018] [Accepted: 06/27/2018] [Indexed: 12/28/2022] Open
Abstract
Aflatoxin biosynthesis is correlated with oxidative stress and is proposed to function as a secondary defense mechanism to redundant intracellular reactive oxygen species (ROS). We find that the antioxidant gallic acid inhibits aflatoxin formation and growth in Aspergillus flavus in a dose-dependent manner. Global expression analysis (RNA-Seq) of gallic acid-treated A. flavus showed that 0.8% (w/v) gallic acid revealed two possible routes of aflatoxin inhibition. Gallic acid significantly inhibited the expression of farB, encoding a transcription factor that participates in peroxisomal fatty acid β-oxidation, a fundamental contributor to aflatoxin production. Secondly, the carbon repression regulator encoding gene, creA, was significantly down regulated by gallic acid treatment. CreA is necessary for aflatoxin synthesis, and aflatoxin biosynthesis genes were significantly downregulated in ∆creA mutants. In addition, the results of antioxidant enzyme activities and the lipid oxidation levels coupled with RNA-Seq data of antioxidant genes indicated that gallic acid may reduce oxidative stress through the glutathione- and thioredoxin-dependent systems in A. flavus.
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Affiliation(s)
- Xixi Zhao
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China.
| | - Qing-Qing Zhi
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China.
| | - Jie-Ying Li
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China.
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Zhu-Mei He
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China.
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Lv C, Wang P, Ma L, Zheng M, Liu Y, Xing F. Large-Scale Comparative Analysis of Eugenol-Induced/Repressed Genes Expression in Aspergillus flavus Using RNA-seq. Front Microbiol 2018; 9:1116. [PMID: 29899734 PMCID: PMC5988903 DOI: 10.3389/fmicb.2018.01116] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 05/11/2018] [Indexed: 11/24/2022] Open
Abstract
Aflatoxin B1 (AFB1), which is mainly produced by Aspergillus flavus and Aspergillus parasiticus, is the most toxic and hepatocarcinogenic polyketide known. Chemical fungicides are currently utilized to reduce this fungal contaminant, but they are potentially harmful to human health and the environment. Therefore, natural anti-aflatoxigenic products are used as sustainable alternatives to control food and feed contamination. For example, eugenol, presents in many essential oils, has been identified as an aflatoxin inhibitor. However, its exact mechanism of inhibition is yet to be clarified. In this study, the anti-aflatoxigenic mechanism of eugenol in A. flavus was determined using a comparative transcriptomic approach. Twenty of twenty-nine genes in the aflatoxin biosynthetic pathway were down-regulated by eugenol. The most strongly down-regulated gene was aflMa, followed by aflI, aflJ, aflCa, aflH, aflNa, aflE, aflG, aflM, aflD, and aflP. However, the expression of the regulator gene aflR did not change significantly and the expression of aflS was slightly up-regulated. The down-regulation of the global regulator gene veA resulted in the up-regulation of srrA, and the down-regulation of ap-1 and mtfA. The early developmental regulator brlA was profoundly up-regulated in A. flavus after eugenol treatment. These results suggested a model in which eugenol improves fungal development by up-regulating the expression of brlA by the suppression of veA expression and inhibits aflatoxin production through the suppression of veA expression. Exposure to eugenol also caused dysregulated transcript levels of the G protein-coupled receptors (GPCRs) and oxylipins genes. A Gene Ontology analysis indicated that the genes that were highly responsive to eugenol were mainly enriched in RNA-binding functions, suggesting that post-transcriptional modification plays a pivotal role in aflatoxin biosynthesis. KEGG analysis showed that ribosome biogenesis was the most dysregulated pathway, suggesting that eugenol dysregulates ribosome biogenesis, which then interrupts the biosynthesis of Nor-1, Ver-1, and OmtA, and prevents aflatoxisomes performing their normal function in aflatoxin production. In conclusion, our results indicated that eugenol inhibited AFB1 production by modulating the expression of structural genes in aflatoxin pathway, fungal antioxidant status, post-transcriptional modifications and biosynthesis of backbone enzymes in A. flavus.
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Affiliation(s)
- Cong Lv
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Ping Wang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Longxue Ma
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Mumin Zheng
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Yang Liu
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Fuguo Xing
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
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Kurucz V, Krüger T, Antal K, Dietl AM, Haas H, Pócsi I, Kniemeyer O, Emri T. Additional oxidative stress reroutes the global response of Aspergillus fumigatus to iron depletion. BMC Genomics 2018; 19:357. [PMID: 29747589 PMCID: PMC5946477 DOI: 10.1186/s12864-018-4730-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 04/26/2018] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Aspergillus fumigatus has to cope with a combination of several stress types while colonizing the human body. A functional interplay between these different stress responses can increase the chances of survival for this opportunistic human pathogen during the invasion of its host. In this study, we shed light on how the H2O2-induced oxidative stress response depends on the iron available to this filamentous fungus, using transcriptomic analysis, proteomic profiles, and growth assays. RESULTS The applied H2O2 treatment, which induced only a negligible stress response in iron-replete cultures, deleteriously affected the fungus under iron deprivation. The majority of stress-induced changes in gene and protein expression was not predictable from data coming from individual stress exposure and was only characteristic for the combination of oxidative stress plus iron deprivation. Our experimental data suggest that the physiological effects of combined stresses and the survival of the fungus highly depend on fragile balances between economization of iron and production of essential iron-containing proteins. One observed strategy was the overproduction of iron-independent antioxidant proteins to combat oxidative stress during iron deprivation, e.g. the upregulation of superoxide dismutase Sod1, the thioredoxin reductase Trr1, and the thioredoxin orthologue Afu5g11320. On the other hand, oxidative stress induction overruled iron deprivation-mediated repression of several genes. In agreement with the gene expression data, growth studies underlined that in A. fumigatus iron deprivation aggravates oxidative stress susceptibility. CONCLUSIONS Our data demonstrate that studying stress responses under separate single stress conditions is not sufficient to understand how A. fumigatus adapts in a complex and hostile habitat like the human body. The combinatorial stress of iron depletion and hydrogen peroxide caused clear non-additive effects upon the stress response of A. fumigatus. Our data further supported the view that the ability of A. fumigatus to cause diseases in humans strongly depends on its fitness attributes and less on specific virulence factors. In summary, A. fumigatus is able to mount and coordinate complex and efficient responses to combined stresses like iron deprivation plus H2O2-induced oxidative stress, which are exploited by immune cells to kill fungal pathogens.
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Affiliation(s)
- Vivien Kurucz
- Department of Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen, Egyetem tér 1, Debrecen, H-4032 Hungary
| | - Thomas Krüger
- Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (HKI), 07745 Jena, Germany
| | - Károly Antal
- Department of Zoology, Faculty of Sciences, Eszterházy Károly University, Eszterházy tér 1, Eger, H-3300 Hungary
| | - Anna-Maria Dietl
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, A6020 Innsbruck, Austria
| | - Hubertus Haas
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, A6020 Innsbruck, Austria
| | - István Pócsi
- Department of Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen, Egyetem tér 1, Debrecen, H-4032 Hungary
| | - Olaf Kniemeyer
- Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (HKI), 07745 Jena, Germany
| | - Tamás Emri
- Department of Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen, Egyetem tér 1, Debrecen, H-4032 Hungary
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Lee Y, Son H, Shin JY, Choi GJ, Lee Y. Genome-wide functional characterization of putative peroxidases in the head blight fungus Fusarium graminearum. MOLECULAR PLANT PATHOLOGY 2018; 19:715-730. [PMID: 28387997 PMCID: PMC6638050 DOI: 10.1111/mpp.12557] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/28/2017] [Accepted: 04/01/2017] [Indexed: 06/01/2023]
Abstract
Reactive oxygen species (ROS) are associated with various developmental processes and host-pathogen interactions in pathogenic fungi. Peroxidases are a group of ROS-detoxifying enzymes that are involved in the oxidative stress response and in a variety of physiological processes. In this study, we performed a genome-wide functional characterization of putative peroxidase genes in Fusarium graminearum, a head blight pathogen of cereal crops. We identified 31 putative peroxidase genes and generated deletion mutants for these genes. Twenty-six of the deletion mutants showed developmental phenotypes indistinguishable from that of the wild-type, and five deletion mutants exhibited phenotypic changes in at least one phenotypic category. Four deletion mutants, fca6, fca7, fpx1 and fpx15, showed increased sensitivity to extracellular H2 O2 . Deletion mutants of FCA7 also exhibited reduced virulence and increased trichothecene production compared with those of the wild-type strain, suggesting that Fca7 may play an important role in the host-pathogen interaction in F. graminearum. To identify the transcription factors (TFs) regulating FCA6, FCA7, FPX1 and FPX15 in response to oxidative stress, we screened an F. graminearum TF mutant library for growth in the presence of H2 O2 and found that multiple TFs co-regulated the expression of FCA7 under oxidative stress conditions. These results demonstrate that a complex network of transcriptional regulators of antioxidant genes is involved in oxidative stress responses in this fungus. Moreover, our study provides insights into the roles of peroxidases in developmental processes and host-pathogen interactions in plant-pathogenic fungi.
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Affiliation(s)
- Yoonji Lee
- Department of Agricultural BiotechnologySeoul National UniversitySeoul08826South Korea
| | - Hokyoung Son
- Center for Food and BioconvergenceSeoul National UniversitySeoul08826South Korea
| | - Ji Young Shin
- Department of Agricultural BiotechnologySeoul National UniversitySeoul08826South Korea
| | - Gyung Ja Choi
- Eco‐friendly New Materials Research Group, Research Center for Biobased Chemistry, Division of Convergence ChemistryKorea Research Institute of Chemical TechnologyDaejeon34114South Korea
| | - Yin‐Won Lee
- Department of Agricultural BiotechnologySeoul National UniversitySeoul08826South Korea
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Activation of Aflatoxin Biosynthesis Alleviates Total ROS in Aspergillus parasiticus. Toxins (Basel) 2018; 10:toxins10020057. [PMID: 29382166 PMCID: PMC5848158 DOI: 10.3390/toxins10020057] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 01/06/2018] [Accepted: 01/16/2018] [Indexed: 01/01/2023] Open
Abstract
An aspect of mycotoxin biosynthesis that remains unclear is its relationship with the cellular management of reactive oxygen species (ROS). Here we conduct a comparative study of the total ROS production in the wild-type strain (SU-1) of the plant pathogen and aflatoxin producer, Aspergillus parasiticus, and its mutant strain, AFS10, in which the aflatoxin biosynthesis pathway is blocked by disruption of its pathway regulator, aflR. We show that SU-1 demonstrates a significantly faster decrease in total ROS than AFS10 between 24 h to 48 h, a time window within which aflatoxin synthesis is activated and reaches peak levels in SU-1. The impact of aflatoxin synthesis in alleviation of ROS correlated well with the transcriptional activation of five superoxide dismutases (SOD), a group of enzymes that protect cells from elevated levels of a class of ROS, the superoxide radicals (O₂-). Finally, we show that aflatoxin supplementation to AFS10 growth medium results in a significant reduction of total ROS only in 24 h cultures, without resulting in significant changes in SOD gene expression. Our findings show that the activation of aflatoxin biosynthesis in A. parasiticus alleviates ROS generation, which in turn, can be both aflR dependent and aflatoxin dependent.
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50
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Limaye A, Yu RC, Chou CC, Liu JR, Cheng KC. Protective and Detoxifying Effects Conferred by Dietary Selenium and Curcumin against AFB1-Mediated Toxicity in Livestock: A Review. Toxins (Basel) 2018; 10:E25. [PMID: 29301315 PMCID: PMC5793112 DOI: 10.3390/toxins10010025] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 12/28/2017] [Accepted: 12/28/2017] [Indexed: 12/21/2022] Open
Abstract
Aflatoxin B1 (AFB1), among other aflatoxins of the aflatoxin family, is the most carcinogenic and hazardous mycotoxin to animals and human beings with very high potency leading to aflatoxicosis. Selenium is an essential trace mineral possessing powerful antioxidant functions. Selenium is widely reported as an effective antioxidant against aflatoxicosis. By preventing oxidative liver damage, suppressing pro-apoptotic proteins and improving immune status in AFB1 affected animals; selenium confers specific protection against AFB1 toxicity. Meticulous supplementation of animal feed by elemental selenium in the organic and inorganic forms has proven to be effective to ameliorate AFB1 toxicity. Curcumin is another dietary agent of importance in tackling aflatoxicosis. Curcumin is one of the major active ingredients in the tubers of a spice Curcuma longa L., a widely reported antioxidant, anticarcinogenic agent with reported protective potential against aflatoxin-mediated liver damage. Curcumin restricts the aflatoxigenic potential of Aspergillusflavus. Curcumin inhibits cytochrome P450 isoenzymes, particularly CYP2A6 isoform; thereby reducing the formation of AFB1-8, 9-epoxide and other toxic metabolites causing aflatoxicosis. In this review, we have briefly reviewed important aflatoxicosis symptoms among animals. With the main focus on curcumin and selenium, we have reviewed their underlying protective mechanisms in different animals along with their extraction and production methods for feed applications.
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Affiliation(s)
- Aniket Limaye
- Institute of Biotechnology, National Taiwan University, Taipei 10617, Taiwan.
| | - Roch-Chui Yu
- Graduate Institute of Food Science Technology, National Taiwan University, Taipei 10617, Taiwan.
| | - Cheng-Chun Chou
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 404, Taiwan.
| | - Je-Ruei Liu
- Institute of Biotechnology, National Taiwan University, Taipei 10617, Taiwan.
| | - Kuan-Chen Cheng
- Institute of Biotechnology, National Taiwan University, Taipei 10617, Taiwan.
- Graduate Institute of Food Science Technology, National Taiwan University, Taipei 10617, Taiwan.
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 404, Taiwan.
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