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Li T, Li J, Wang J, Xue KS, Su X, Qu H, Duan X, Jiang Y. The occurrence and management of fumonisin contamination across the food production and supply chains. J Adv Res 2024; 60:13-26. [PMID: 37544477 PMCID: PMC11156612 DOI: 10.1016/j.jare.2023.08.001] [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: 06/01/2022] [Revised: 04/05/2023] [Accepted: 08/02/2023] [Indexed: 08/08/2023] Open
Abstract
BACKGROUND Fumonisins (FUMs) are among the most common mycotoxins in plant-derived food products. FUMs contamination has considerably impacted human and animal health, while causing significant economic losses. Hence, management of FUMs contamination in food production and supply chains is needed. The toxicities of FUMs have been widely investigated. FUMs management has been reported and several available strategies have been developed successfully to mitigate FUMs contamination present in foods. However, currently available management of FUMs contamination from different phases of food chains and the mechanisms of some major strategies are not comprehensively summarized. AIM OF REVIEW This review comprehensively characterize the occurrence, impacts, and management of FUMs contamination across food production and supply chains. Pre- and post-harvest strategies to prevent FUMs contamination also are reviewed, with an emphasis on the potential applications and the mechanisms of major mitigation strategies. The presence of modified FUMs products and their potential toxic effects are also considered. Importantly, the potential application of biotechnological approaches and emerging technologies are enunciated. KEY SCIENTIFIC CONCEPTS OF REVIEW Currently available pre- and post-harvest management of FUMs contamination primarily involves prevention and decontamination. Prevention strategies are mainly based on limiting fungal growth and FUMs biosynthesis. Decontamination strategies are implemented through alkalization, hydrolysis, thermal or chemical transformation, and enzymatic or chemical degradation of FUMs. Concerns have been raised about toxicities of modified FUMs derivatives, which presents challenges for reducing FUMs contamination in foods with conventional methodologies. Integrated prevention and decontamination protocols are recommended to control FUMs contamination across entire value chains in developed countries. In developing countries, several other approaches, including cultivating, introducing Bt maize, simple sorting/cleaning, and dehulling, are suggested. Future studies should focus on biotechnological approaches, emerging technologies, and metagenomic/genomic identification of new degradation enzymes that could allow better opportunities to manage FUMs contamination in the entire food system.
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Affiliation(s)
- Taotao Li
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Jiajia Li
- College of Tourism and Planning, Pingdingshan University, Pingdingshan 467000, China
| | - Jiasheng Wang
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, USA.
| | - Kathy S Xue
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, USA
| | - Xinguo Su
- Tropical Agriculture and Forestry College, Guangdong AIB Polytechnic, No. 198, Yueken Road, Tianhe District, Guangzhou 510507, China
| | - Hongxia Qu
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Xuewu Duan
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Yueming Jiang
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; College of Advanced Agricultural Sciences, University of the Chinese Academy of Sciences, Beijing 100039, China.
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Moonjely S, Ebert M, Paton-Glassbrook D, Noel ZA, Roze L, Shay R, Watkins T, Trail F. Update on the state of research to manage Fusarium head blight. Fungal Genet Biol 2023; 169:103829. [PMID: 37666446 DOI: 10.1016/j.fgb.2023.103829] [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: 05/10/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/06/2023]
Abstract
Fusarium head blight (FHB) is one of the most devastating diseases of cereal crops, causing severe reduction in yield and quality of grain worldwide. In the United States, the major causal agent of FHB is the mycotoxigenic fungus, Fusarium graminearum. The contamination of grain with mycotoxins, including deoxynivalenol and zearalenone, is a particularly serious concern due to its impact on the health of humans and livestock. For the past few decades, multidisciplinary studies have been conducted on management strategies designed to reduce the losses caused by FHB. However, effective management is still challenging due to the emergence of fungicide-tolerant strains of F. graminearum and the lack of highly resistant wheat and barley cultivars. This review presents multidisciplinary approaches that incorporate advances in genomics, genetic-engineering, new fungicide chemistries, applied biocontrol, and consideration of the disease cycle for management of FHB.
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Affiliation(s)
- Soumya Moonjely
- Department of Plant Biology, Michigan State University, East Lansing, MI 48823, USA
| | - Malaika Ebert
- Department of Plant Biology, Michigan State University, East Lansing, MI 48823, USA
| | - Drew Paton-Glassbrook
- Department of Plant Biology, Michigan State University, East Lansing, MI 48823, USA; Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48823, USA
| | - Zachary A Noel
- Department of Plant Biology, Michigan State University, East Lansing, MI 48823, USA
| | - Ludmila Roze
- Department of Plant Biology, Michigan State University, East Lansing, MI 48823, USA
| | - Rebecca Shay
- Department of Plant Biology, Michigan State University, East Lansing, MI 48823, USA
| | - Tara Watkins
- Department of Plant Biology, Michigan State University, East Lansing, MI 48823, USA; Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48823, USA
| | - Frances Trail
- Department of Plant Biology, Michigan State University, East Lansing, MI 48823, USA; Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48823, USA.
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Marcial-Quino J, Fierro F, Fernández FJ, Montiel-Gonzalez AM, Sierra-Palacios E, Tomasini A. Silencing of Amylomyces rouxii aspartic II protease by siRNA to increase tyrosinase activity. Fungal Biol 2023; 127:1415-1425. [PMID: 37993253 DOI: 10.1016/j.funbio.2023.10.004] [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: 04/17/2023] [Revised: 09/20/2023] [Accepted: 10/20/2023] [Indexed: 11/24/2023]
Abstract
Amylomyces rouxii is a zygomycete that produces extracellular protease and tyrosinase. The tyrosinase activity is negatively regulated by the proteases and, which attempts to purify the tyrosinase (tyr) enzyme that has been hampered by the presence of a protease that co-purified with it. In this work we identified genes encoding aspartic protease II (aspII) and VI of A. rouxii. Using an RNAi strategy based on the generation of a siRNA by transcription from two opposite-orientated promoters, the expression of these two proteases was silenced, showing that this molecular tool is suitable for gene silencing in Amylomyces. The transformant strains showed a significant attenuation of the transcripts (determined by RT-qPCR), with respective inhibition of the protease activity. In the case of aspII, inhibition was in the range of 43-90 % in different transformants, which correlated well with up to a five-fold increase in tyr activity with respect to the wild type and control strains. In contrast, silencing of aspVI caused a 43-65 % decrease in protease activity but had no significant effect on the tyr activity. The results show that aspII has a negative effect on tyr activity, and that the silencing of this protease is important to obtain strains with high levels of tyr activity.
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Affiliation(s)
- Jaime Marcial-Quino
- Laboratorio de Biología Molecular, Centro de Investigación en Genética y Ambiente, Universidad Autónoma de Tlaxcala, Tlaxcala, 90120, Mexico
| | - Francisco Fierro
- Depto. de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa, Apdo, Postal 55-535, C.P. 09340, Mexico City, Mexico
| | - Francisco José Fernández
- Depto. de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa, Apdo, Postal 55-535, C.P. 09340, Mexico City, Mexico
| | - Alba Mónica Montiel-Gonzalez
- Laboratorio de Biología Molecular, Centro de Investigación en Genética y Ambiente, Universidad Autónoma de Tlaxcala, Tlaxcala, 90120, Mexico
| | - Edgar Sierra-Palacios
- Colegio de Ciencias y Humanidades, Plantel Casa Libertad, Universidad Autónoma de la Ciudad de México, Ciudad de Mexico, 09620, Mexico
| | - Araceli Tomasini
- Depto. de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa, Apdo, Postal 55-535, C.P. 09340, Mexico City, Mexico.
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Raruang Y, Omolehin O, Hu D, Wei Q, Promyou S, Parekattil LJ, Rajasekaran K, Cary JW, Wang K, Chen ZY. Targeting the Aspergillus flavus p2c gene through host-induced gene silencing reduces A. flavus infection and aflatoxin contamination in transgenic maize. FRONTIERS IN PLANT SCIENCE 2023; 14:1150086. [PMID: 37229129 PMCID: PMC10203651 DOI: 10.3389/fpls.2023.1150086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/11/2023] [Indexed: 05/27/2023]
Abstract
Aspergillus flavus is an opportunistic fungal pathogen that infects maize and produces aflatoxins. Using biocontrol or developing resistant cultivars to reduce aflatoxin contamination has only achieved limited success. Here, the A. flavus polygalacturonase gene (p2c) was targeted for suppression through host-induced gene silencing (HIGS) to reduce aflatoxin contamination in maize. An RNAi vector carrying a portion of the p2c gene was constructed and transformed into maize B104. Thirteen out of fifteen independent transformation events were confirmed to contain p2c. The T2 generation kernels containing the p2c transgene had less aflatoxin than those without the transgene in six out of eleven events we examined. Homozygous T3 transgenic kernels from four events produced significantly less aflatoxins (P ≤ 0.02) than the kernels from the null or B104 controls under field inoculation conditions. The F1 kernels from the crosses between six elite inbred lines with P2c5 and P2c13 also supported significantly less aflatoxins (P ≤ 0.02) than those from the crosses with null plants. The reduction in aflatoxin ranged from 93.7% to 30.3%. Transgenic leaf (T0 and T3) and kernel tissues (T4) were also found to have significantly higher levels of p2c gene-specific small RNAs. Further, homozygous transgenic maize kernels had significantly less fungal growth (27~40 fold) than the null control kernels 10 days after fungal inoculation in the field. The calculated suppression of p2c gene expression based on RNAseq data was 57.6% and 83.0% in P2c5 and P2c13 events, respectively. These results indicate clearly that the reduced aflatoxin production in the transgenic kernels is due to RNAi-based suppression of p2c expression, which results in reduced fungal growth and toxin production.
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Affiliation(s)
- Yenjit Raruang
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA, United States
| | - Olanike Omolehin
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA, United States
| | - Dongfang Hu
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA, United States
| | - Qijian Wei
- Food and Feed Safety Research Unit, United States Department of Agriculture – Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, United States
| | - Surassawadee Promyou
- Faculty of Natural Resources and Agro-Industry, Kasetsart University, Sakonnakhon, Thailand
| | - Lidiya J. Parekattil
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA, United States
| | - Kanniah Rajasekaran
- Food and Feed Safety Research Unit, United States Department of Agriculture – Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, United States
| | - Jeffrey W. Cary
- Food and Feed Safety Research Unit, United States Department of Agriculture – Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, United States
| | - Kan Wang
- Department of Agronomy, Iowa State University, Ames, IA, United States
| | - Zhi-Yuan Chen
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA, United States
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Prasad K, Yogendra K, Sanivarapu H, Rajasekaran K, Cary JW, Sharma KK, Bhatnagar-Mathur P. Multiplexed Host-Induced Gene Silencing of Aspergillus flavus Genes Confers Aflatoxin Resistance in Groundnut. Toxins (Basel) 2023; 15:toxins15050319. [PMID: 37235354 DOI: 10.3390/toxins15050319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/18/2023] [Accepted: 04/23/2023] [Indexed: 05/28/2023] Open
Abstract
Aflatoxins are immunosuppressive and carcinogenic secondary metabolites, produced by the filamentous ascomycete Aspergillus flavus, that are hazardous to animal and human health. In this study, we show that multiplexed host-induced gene silencing (HIGS) of Aspergillus flavus genes essential for fungal sporulation and aflatoxin production (nsdC, veA, aflR, and aflM) confers enhanced resistance to Aspergillus infection and aflatoxin contamination in groundnut (<20 ppb). Comparative proteomic analysis of contrasting groundnut genotypes (WT and near-isogenic HIGS lines) supported a better understanding of the molecular processes underlying the induced resistance and identified several groundnut metabolites that might play a significant role in resistance to Aspergillus infection and aflatoxin contamination. Fungal differentiation and pathogenicity proteins, including calmodulin, transcriptional activator-HacA, kynurenine 3-monooxygenase 2, VeA, VelC, and several aflatoxin pathway biosynthetic enzymes, were downregulated in Aspergillus infecting the HIGS lines. Additionally, in the resistant HIGS lines, a number of host resistance proteins associated with fatty acid metabolism were strongly induced, including phosphatidylinositol phosphate kinase, lysophosphatidic acyltransferase-5, palmitoyl-monogalactosyldiacylglycerol Δ-7 desaturase, ceramide kinase-related protein, sphingolipid Δ-8 desaturase, and phospholipase-D. Combined, this knowledge can be used for groundnut pre-breeding and breeding programs to provide a safe and secure food supply.
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Affiliation(s)
- Kalyani Prasad
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad 502324, India
| | - Kalenahalli Yogendra
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad 502324, India
| | - Hemalatha Sanivarapu
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad 502324, India
| | - Kanniah Rajasekaran
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture (USDA/ARS), New Orleans, LA 70124, USA
| | - Jeffrey W Cary
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture (USDA/ARS), New Orleans, LA 70124, USA
| | - Kiran K Sharma
- Sustainable Agriculture Program, The Energy and Resources Institute (TERI), India Habitat Center, New Delhi 110003, India
| | - Pooja Bhatnagar-Mathur
- International Maize and Wheat Improvement Center (CIMMYT), El Batán, Texcoco 56237, Mexico
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Putative Core Transcription Factors Affecting Virulence in Aspergillus flavus during Infection of Maize. J Fungi (Basel) 2023; 9:jof9010118. [PMID: 36675939 PMCID: PMC9861280 DOI: 10.3390/jof9010118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/20/2022] [Accepted: 12/23/2022] [Indexed: 01/17/2023] Open
Abstract
Aspergillus flavus is an opportunistic pathogen responsible for millions of dollars in crop losses annually and negative health impacts on crop consumers globally. A. flavus strains have the potential to produce aflatoxin and other toxic secondary metabolites, which often increase during plant colonization. To mitigate the impacts of this international issue, we employ a range of strategies to directly impact fungal physiology, growth and development, thus requiring knowledge on the underlying molecular mechanisms driving these processes. Here we utilize RNA-sequencing data that are obtained from in situ assays, whereby Zea mays kernels are inoculated with A. flavus strains, to select transcription factors putatively driving virulence-related gene networks. We demonstrate, through growth, sporulation, oxidative stress-response and aflatoxin/CPA analysis, that three A. flavus strains with knockout mutations for the putative transcription factors AFLA_089270, AFLA_112760, and AFLA_031450 demonstrate characteristics such as reduced growth capacity and decreased aflatoxin/CPA accumulation in kernels consistent with decreased fungal pathogenicity. Furthermore, AFLA_089270, also known as HacA, eliminates CPA production and impacts the fungus's capacity to respond to highly oxidative conditions, indicating an impact on plant colonization. Taken together, these data provide a sound foundation for elucidating the downstream molecular pathways potentially contributing to fungal virulence.
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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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An NN, Shang N, Zhao X, Tie XY, Guo WB, Li D, Wang LJ, Wang Y. Occurrence, Regulation, and Emerging Detoxification Techniques of Aflatoxins in Maize: A Review. FOOD REVIEWS INTERNATIONAL 2022. [DOI: 10.1080/87559129.2022.2158339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Nan-nan An
- College of Engineering, Beijing Advanced Innovation Center for Food Nutrition and Human Health, National Energy R & D Center for Non-food Biomass, China Agricultural University, Beijing, China
| | - Nan Shang
- College of Engineering, Beijing Advanced Innovation Center for Food Nutrition and Human Health, National Energy R & D Center for Non-food Biomass, China Agricultural University, Beijing, China
| | - Xia Zhao
- College of Food Science and Nutritional Engineering, Beijing Key Laboratory of Functional Food from Plant Resources, China Agricultural University, Beijing, China
| | - Xiao-yu Tie
- College of Engineering, Beijing Advanced Innovation Center for Food Nutrition and Human Health, National Energy R & D Center for Non-food Biomass, China Agricultural University, Beijing, China
| | - Wen-bo Guo
- College of Engineering, Beijing Advanced Innovation Center for Food Nutrition and Human Health, National Energy R & D Center for Non-food Biomass, China Agricultural University, Beijing, China
| | - Dong Li
- College of Engineering, Beijing Advanced Innovation Center for Food Nutrition and Human Health, National Energy R & D Center for Non-food Biomass, China Agricultural University, Beijing, China
| | - Li-jun Wang
- College of Food Science and Nutritional Engineering, Beijing Key Laboratory of Functional Food from Plant Resources, China Agricultural University, Beijing, China
| | - Yong Wang
- School of Chemical Engineering, University of New South Wales, Kensington, New South Wales, Australia
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Mycotoxin risks are lower in biotech corn. Curr Opin Biotechnol 2022; 78:102792. [PMID: 36088737 DOI: 10.1016/j.copbio.2022.102792] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 07/29/2022] [Accepted: 08/08/2022] [Indexed: 12/14/2022]
Abstract
Mycotoxins are food contaminants that occur when toxigenic fungi colonize crops. Unfortunately, corn, a major staple crop worldwide, is highly susceptible to mycotoxin contamination. Some mycotoxins, most notably aflatoxin, cause human cancer and other harmful effects such as immunotoxicity and growth impairment. Hence, many nations have set food-safety standards on mycotoxins. Aside from regulations, good agricultural and manufacturing practices lower mycotoxin risks. Agricultural biotechnology has made notable advances in reducing mycotoxins recently. While transgenic Bt corn has been known for years to reduce the mycotoxin fumonisin, new studies have shown its benefit in reducing aflatoxin as well. Other transgenic and RNA-interference corn hybrids target mycotoxin reduction specifically, and gene editing through clustered regularly interspaced short palindromic repeat systems has focused on preventing mycotoxin biosynthesis.
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Ray P, Sahu D, Aminedi R, Chandran D. Concepts and considerations for enhancing RNAi efficiency in phytopathogenic fungi for RNAi-based crop protection using nanocarrier-mediated dsRNA delivery systems. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:977502. [PMID: 37746174 PMCID: PMC10512274 DOI: 10.3389/ffunb.2022.977502] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/19/2022] [Indexed: 09/26/2023]
Abstract
Existing, emerging, and reemerging strains of phytopathogenic fungi pose a significant threat to agricultural productivity globally. This risk is further exacerbated by the lack of resistance source(s) in plants or a breakdown of resistance by pathogens through co-evolution. In recent years, attenuation of essential pathogen gene(s) via double-stranded (ds) RNA-mediated RNA interference (RNAi) in host plants, a phenomenon known as host-induced gene silencing, has gained significant attention as a way to combat pathogen attack. Yet, due to biosafety concerns regarding transgenics, country-specific GMO legislation has limited the practical application of desirable attributes in plants. The topical application of dsRNA/siRNA targeting essential fungal gene(s) through spray-induced gene silencing (SIGS) on host plants has opened up a transgene-free avenue for crop protection. However, several factors influence the outcome of RNAi, including but not limited to RNAi mechanism in plant/fungi, dsRNA/siRNA uptake efficiency, dsRNA/siRNA design parameters, dsRNA stability and delivery strategy, off-target effects, etc. This review emphasizes the significance of these factors and suggests appropriate measures to consider while designing in silico and in vitro experiments for successful RNAi in open-field conditions. We also highlight prospective nanoparticles as smart delivery vehicles for deploying RNAi molecules in plant systems for long-term crop protection and ecosystem compatibility. Lastly, we provide specific directions for future investigations that focus on blending nanotechnology and RNAi-based fungal control for practical applications.
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Affiliation(s)
- Poonam Ray
- Laboratory of Plant-Microbe Interactions, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
| | - Debashish Sahu
- Laboratory of Plant-Microbe Interactions, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
| | - Raghavendra Aminedi
- Division of Genomic Resources, ICAR-National Bureau of Plant Genetic Resources, New Delhi, India
| | - Divya Chandran
- Laboratory of Plant-Microbe Interactions, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
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11
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Schmidt MA, Mao Y, Opoku J, Mehl HL. Enzymatic degradation is an effective means to reduce aflatoxin contamination in maize. BMC Biotechnol 2021; 21:70. [PMID: 34920704 PMCID: PMC8684248 DOI: 10.1186/s12896-021-00730-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 11/30/2021] [Indexed: 12/25/2022] Open
Abstract
Background Aflatoxins are carcinogenic compounds produced by certain species of Aspergillus fungi. The consumption of crops contaminated with this toxin cause serious detrimental health effects, including death, in both livestock and humans. As a consequence, both the detection and quantification of this toxin in food/feed items is tightly regulated with crops exceeding the allowed limits eliminated from food chains. Globally, this toxin causes massive agricultural and economic losses each year. Results In this paper we investigate the feasibility of using an aflatoxin-degrading enzyme strategy to reduce/eliminate aflatoxin loads in developing maize kernels. We used an endoplasmic reticulum (ER) targeted sub-cellular compartmentalization stabilizing strategy to accumulate an aflatoxin-degrading enzyme isolated from the edible Honey mushroom Armillariella tabescens and expressed it in embryo tissue in developing maize kernels. Three transgenic maize lines that were determined to be expressing the aflatoxin-degrading enzyme both at the RNA and protein level, were challenged with the aflatoxin-producing strain Aspergillus flavus AF13 and shown to accumulate non-detectable levels of aflatoxin at 14-days post-infection and significantly reduced levels of aflatoxin at 30-days post-infection compared to nontransgenic control Aspergillus-challenged samples. Conclusions The expression of an aflatoxin-degrading enzyme in developing maize kernels was shown to be an effective means to control aflatoxin in maize in pre-harvest conditions. This aflatoxin-degradation strategy could play a significant role in the enhancement of both US and global food security and sustainability. Supplementary Information The online version contains supplementary material available at 10.1186/s12896-021-00730-6.
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Affiliation(s)
- Monica A Schmidt
- BIO5 Institute, University of Arizona, 1657 E. Helen St, Tucson, AZ, 85718, USA.
| | - Yizhou Mao
- BIO5 Institute, University of Arizona, 1657 E. Helen St, Tucson, AZ, 85718, USA
| | - Joseph Opoku
- Arid Land Agricultural Research Center, USDA Agricultural Research Service, 416 W Congress St, Tucson, AZ, 85701, USA
| | - Hillary L Mehl
- Arid Land Agricultural Research Center, USDA Agricultural Research Service, 416 W Congress St, Tucson, AZ, 85701, USA
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Rajput M, Choudhary K, Kumar M, Vivekanand V, Chawade A, Ortiz R, Pareek N. RNA Interference and CRISPR/Cas Gene Editing for Crop Improvement: Paradigm Shift towards Sustainable Agriculture. PLANTS 2021; 10:plants10091914. [PMID: 34579446 PMCID: PMC8467553 DOI: 10.3390/plants10091914] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 01/09/2023]
Abstract
With the rapid population growth, there is an urgent need for innovative crop improvement approaches to meet the increasing demand for food. Classical crop improvement approaches involve, however, a backbreaking process that cannot equipoise with increasing crop demand. RNA-based approaches i.e., RNAi-mediated gene regulation and the site-specific nuclease-based CRISPR/Cas9 system for gene editing has made advances in the efficient targeted modification in many crops for the higher yield and resistance to diseases and different stresses. In functional genomics, RNA interference (RNAi) is a propitious gene regulatory approach that plays a significant role in crop improvement by permitting the downregulation of gene expression by small molecules of interfering RNA without affecting the expression of other genes. Gene editing technologies viz. the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein (CRISPR/Cas) have appeared prominently as a powerful tool for precise targeted modification of nearly all crops' genome sequences to generate variation and accelerate breeding efforts. In this regard, the review highlights the diverse roles and applications of RNAi and CRISPR/Cas9 system as powerful technologies to improve agronomically important plants to enhance crop yields and increase tolerance to environmental stress (biotic or abiotic). Ultimately, these technologies can prove to be important in view of global food security and sustainable agriculture.
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Affiliation(s)
- Meenakshi Rajput
- Department of Microbiology, School of Life Sciences, Central University of Rajasthan, Ajmer 305801, Rajasthan, India; (M.R.); (K.C.); (M.K.)
| | - Khushboo Choudhary
- Department of Microbiology, School of Life Sciences, Central University of Rajasthan, Ajmer 305801, Rajasthan, India; (M.R.); (K.C.); (M.K.)
| | - Manish Kumar
- Department of Microbiology, School of Life Sciences, Central University of Rajasthan, Ajmer 305801, Rajasthan, India; (M.R.); (K.C.); (M.K.)
| | - V. Vivekanand
- Centre for Energy and Environment, Malaviya National Institute of Technology, Jaipur 302017, Rajasthan, India;
| | - Aakash Chawade
- Department of Plant Breeding, Swedish University of Agricultural Sciences, P.O. Box 101, 230 53 Alnarp, Sweden;
- Correspondence: (A.C.); (N.P.)
| | - Rodomiro Ortiz
- Department of Plant Breeding, Swedish University of Agricultural Sciences, P.O. Box 101, 230 53 Alnarp, Sweden;
| | - Nidhi Pareek
- Department of Microbiology, School of Life Sciences, Central University of Rajasthan, Ajmer 305801, Rajasthan, India; (M.R.); (K.C.); (M.K.)
- Correspondence: (A.C.); (N.P.)
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Tian J, Chen C, Sun H, Wang Z, Steinkellner S, Feng J, Liang Y. Proteomic Analysis Reveals the Importance of Exudates on Sclerotial Development in Sclerotinia sclerotiorum. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:1430-1440. [PMID: 33481591 DOI: 10.1021/acs.jafc.0c06685] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Sclerotinia sclerotiorum is a ubiquitous necrotrophic pathogenic fungus causing significant losses in a broad range of plant species. Sclerotia formed by S. sclerotiorum play important roles in both the fungal life cycle and the disease development cycle. Sclerotial exudation during sclerotial development is a characteristic feature of this fungus. In this study, a proteome-level investigation of proteins present in sclerotial exudates was conducted by high-throughput LC-MS/MS analysis. A total of 258 proteins were identified, in which 193 were annotated by GO annotation and 54 were classified by KEGG analysis. Four proteins related to plant cell wall degradation were further validated by measuring the corresponding enzymatic activity of the sclerotial exudates and/or by assessing the gene expression during sclerotial development. Results indicated that the proteins identified in sclerotial exudates help in the development of sclerotia and contribute to host cell necrosis caused by S. sclerotiorum. Furthermore, we proposed that sclerotial exudates can degrade plant cell walls to release carbohydrates that provide nutrition for fungal growth and possibly facilitate fungal cell wall assembly in developing sclerotia. This study also provides new insights on the morphogenesis and pathogenicity of other sclerotia-forming fungi.
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Affiliation(s)
- Jiamei Tian
- College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning 110866, China
- Liaoning Key Laboratory of Plant Pathology, Shenyang Agricultural University, Shenyang, Liaoning 110866, China
| | - Caixia Chen
- College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning 110866, China
- Liaoning Key Laboratory of Plant Pathology, Shenyang Agricultural University, Shenyang, Liaoning 110866, China
| | - Huiying Sun
- College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning 110866, China
- Liaoning Key Laboratory of Plant Pathology, Shenyang Agricultural University, Shenyang, Liaoning 110866, China
| | - Zehao Wang
- College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning 110866, China
- Liaoning Key Laboratory of Plant Pathology, Shenyang Agricultural University, Shenyang, Liaoning 110866, China
| | - Siegrid Steinkellner
- Division of Plant Protection, Department of Crop Sciences, University of Natural Resources and Life Sciences, Vienna 1190, Austria
| | - Jie Feng
- Alberta Plant Health Lab, Alberta Agriculture and Forestry, Edmonton, Alberta T5Y 6H3, Canada
| | - Yue Liang
- College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning 110866, China
- Liaoning Key Laboratory of Plant Pathology, Shenyang Agricultural University, Shenyang, Liaoning 110866, China
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McCaghey M, Shao D, Kurcezewski J, Lindstrom A, Ranjan A, Whitham SA, Conley SP, Williams B, Smith DL, Kabbage M. Host-Induced Gene Silencing of a Sclerotinia sclerotiorum oxaloacetate acetylhydrolase Using Bean Pod Mottle Virus as a Vehicle Reduces Disease on Soybean. FRONTIERS IN PLANT SCIENCE 2021; 12:677631. [PMID: 34354721 PMCID: PMC8329588 DOI: 10.3389/fpls.2021.677631] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/26/2021] [Indexed: 05/05/2023]
Abstract
A lack of complete resistance in the current germplasm complicates the management of Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum in soybean. In this study, we used bean pod mottle virus (BPMV) as a vehicle to down-regulate expression of a key enzyme in the production of an important virulence factor in S. sclerotiorum, oxalic acid (OA). Specifically, we targeted a gene encoding oxaloacetate acetylhydrolase (Ssoah1), because Ssoah1 deletion mutants are OA deficient and non-pathogenic on soybean. We first established that S. sclerotiorum can uptake environmental RNAs by monitoring the translocation of Cy3-labeled double-stranded and small interfering RNA (ds/siRNAs) into fungal hyphae using fluorescent confocal microscopy. This translocation led to a significant decrease in Ssoah1 transcript levels in vitro. Inoculation of soybean plants with BPMV vectors targeting Ssoah1 (pBPMV-OA) also led to decreased expression of Ssoah1. Importantly, pBPMV-OA inoculated plants showed enhanced resistance to S. sclerotiorum compared to empty-vector control plants. Our combined results provide evidence supporting the use of HIGS and exogenous applications of ds/siRNAs targeting virulence factors such as OA as viable strategies for the control of SSR in soybean and as discovery tools that can be used to identify previously unknown virulence factors.
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Affiliation(s)
- Megan McCaghey
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Dandan Shao
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Jake Kurcezewski
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Ally Lindstrom
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Ashish Ranjan
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, United States
| | - Steven A. Whitham
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, United States
| | - Shawn P. Conley
- Department of Agronomy, University of Wisconsin-Madison, Madison, WI, United States
| | - Brett Williams
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Damon L. Smith
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
- Damon L. Smith
| | - Mehdi Kabbage
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
- *Correspondence: Mehdi Kabbage
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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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16
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Raruang Y, Omolehin O, Hu D, Wei Q, Han ZQ, Rajasekaran K, Cary JW, Wang K, Chen ZY. Host Induced Gene Silencing Targeting Aspergillus flavus aflM Reduced Aflatoxin Contamination in Transgenic Maize Under Field Conditions. Front Microbiol 2020; 11:754. [PMID: 32411110 PMCID: PMC7201132 DOI: 10.3389/fmicb.2020.00754] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 03/30/2020] [Indexed: 11/13/2022] Open
Abstract
Maize (Zea mays L.) is one of the major crops susceptible to Aspergillus flavus infection and subsequent contamination with aflatoxins, the most potent naturally produced carcinogenic secondary metabolites. This pathogen can pose serious health concerns and cause severe economic losses due to the Food and Drug Administration (FDA) regulations on permissible levels of aflatoxins in food and feed. Although biocontrol has yielded some successes in managing aflatoxin contamination, enhancing crop resistance is still the preferred choice of management for long-term sustainability. Hence, host induced gene silencing (HIGS) strategy was explored in this study. The A. flavus gene aflM encoding versicolorin dehydrogenase, a key enzyme involved in the aflatoxin biosynthetic pathway, was selected as a possible target for suppression through HIGS. An RNAi vector containing a portion of the aflM gene was constructed and introduced into immature B104 maize zygotic embryos through Agrobacterium transformation. PCR analysis of the genomic DNA from T0 leaf tissue confirmed the presence of the transgene in six out of the seven events. The seeds from the lines that showed reduced aflatoxin production in laboratory aflatoxin kernel screening assay (KSA) have been increased from T1 to T4 generation in the past four years. Changes in aflatoxin resistance in these transgenic kernels have been evaluated under both field and laboratory conditions. The T2 generation kernels containing the transgene from two events out of four examined had less aflatoxin (P ≤ 0.01 and P ≤ 0.08) than those without the transgene. Field-inoculated homozygous T3 and T4 transgenic kernels also revealed lower levels of aflatoxins (P ≤ 0.04) than kernels from the null (segregated non-transgenic samples) or B104 controls. A similar result was observed when the harvested T3 and T4 homozygous transgenic kernels were evaluated under KSA conditions without inoculation (P ≤ 0.003–0.05). These two events were crossed with LH195, LH197, LH210, and PHW79 elite breeding lines and the resulting crosses supported less aflatoxin (P ≤ 0.02) than the crosses made with non-transgenic lines. In addition, significantly higher levels of aflM gene-specific small RNAs were detected in the transgenic leaf and kernel tissues, indicating that the enhanced aflatoxin resistance in the homozygous transgenic kernels is likely due to suppression of aflM expression through HIGS.
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Affiliation(s)
- Yenjit Raruang
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA, United States
| | - Olanike Omolehin
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA, United States
| | - Dongfang Hu
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA, United States
| | - Qijian Wei
- Food and Feed Safety Research Unit, United States Department of Agriculture - Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, United States
| | - Zhu-Qiang Han
- Cash Crops Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Kanniah Rajasekaran
- Food and Feed Safety Research Unit, United States Department of Agriculture - Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, United States
| | - Jeffrey W Cary
- Food and Feed Safety Research Unit, United States Department of Agriculture - Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, United States
| | - Kan Wang
- Department of Agronomy, Iowa State University, Ames, IA, United States
| | - Zhi-Yuan Chen
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA, United States
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Mohamed MA, Abd-Elsalam KA. Nanoparticles and gene silencing for suppression of mycotoxins. NANOMYCOTOXICOLOGY 2020:423-448. [DOI: 10.1016/b978-0-12-817998-7.00018-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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18
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Cui FJ, Wu XH, Tao TL, Zan XY, Sun WJ, Mu DS, Yang Y, Wu D. Functions of a Glucan Synthase Gene GFGLS in Mycelial Growth and Polysaccharide Production of Grifola frondosa. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:8875-8883. [PMID: 31347830 DOI: 10.1021/acs.jafc.9b03569] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Glucan synthase (GLS) gene is known to be involved in the fungal biosynthesis of cell wall, differentiation, and growth. In the present study, a glucan synthase gene (GFGLS) in the edible mushroom Grifola frondosa with a full sequence of 5927 bp encoding a total of 1781 amino acids was cloned and characterized for the first time. GFGLSp is a membrane protein containing two large transmembrane domains connected with a hydrophilic cytoplasmic domain. With a constructed dual promoter RNA silencing vector pAN7-gfgls-dual, a GFGLS-silencing transformant iGFGLS-3 had the lowest GFGLS transcriptional expression level (26.1%) with a shorter length and thinner appearance of the mycelia, as well as decreased mycelial biomass and exo-polysaccharide production of 5.02 and 0.38 g/L, respectively. Further analysis indicated that GFGLS silence influenced slightly the monosaccharide compositions and ratios of mycelial and exo-polysaccharide. These findings suggest that GFGLS could affect mycelial growth and polysaccharide production by downregulating the glucan synthesis.
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Affiliation(s)
- Feng-Jie Cui
- School of Food and Biological Engineering , Jiangsu University , Zhenjiang 212013 , P. R. China
- Jiangxi Provincial Engineering and Technology Center for Food Additives Bio-production , Dexing 334221 , P. R. China
| | - Xi-Hong Wu
- School of Food and Biological Engineering , Jiangsu University , Zhenjiang 212013 , P. R. China
| | - Ting-Lei Tao
- School of Food and Biological Engineering , Jiangsu University , Zhenjiang 212013 , P. R. China
| | - Xin-Yi Zan
- School of Food and Biological Engineering , Jiangsu University , Zhenjiang 212013 , P. R. China
| | - Wen-Jing Sun
- School of Food and Biological Engineering , Jiangsu University , Zhenjiang 212013 , P. R. China
- Jiangxi Provincial Engineering and Technology Center for Food Additives Bio-production , Dexing 334221 , P. R. China
| | - Da-Shuai Mu
- College of Marine Science , Shandong University (Weihai) , Weihai 264209 , P. R. China
| | - Yan Yang
- National Engineering Research Center of Edible Fungi , Shanghai Academy of Agricultural Sciences , Shanghai 201403 , P. R. China
| | - Di Wu
- National Engineering Research Center of Edible Fungi , Shanghai Academy of Agricultural Sciences , Shanghai 201403 , P. R. China
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19
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The Aspergillus flavus rtfA Gene Regulates Plant and Animal Pathogenesis and Secondary Metabolism. Appl Environ Microbiol 2019; 85:AEM.02446-18. [PMID: 30635379 DOI: 10.1128/aem.02446-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 12/31/2018] [Indexed: 02/04/2023] Open
Abstract
Aspergillus flavus is an opportunistic fungal plant and human pathogen and a producer of mycotoxins, including aflatoxin B1 (AFB1). As part of our ongoing studies to elucidate the biological functions of the A. flavus rtfA gene, we examined its role in the pathogenicity of both plant and animal model systems. rtfA encodes a putative RNA polymerase II (Pol II) transcription elongation factor previously characterized in Saccharomyces cerevisiae, Aspergillus nidulans, and Aspergillus fumigatus, where it was shown to regulate several important cellular processes, including morphogenesis and secondary metabolism. In addition, an initial study in A. flavus indicated that rtfA also influences development and production of AFB1; however, its effect on virulence is unknown. The current study reveals that the rtfA gene is indispensable for normal pathogenicity in plants when using peanut seed as an infection model, as well as in animals, as shown in the Galleria mellonella infection model. Interestingly, rtfA positively regulates several processes known to be necessary for successful fungal invasion and colonization of host tissue, such as adhesion to surfaces, protease and lipase activity, cell wall composition and integrity, and tolerance to oxidative stress. In addition, metabolomic analysis revealed that A. flavus rtfA affects the production of several secondary metabolites, including AFB1, aflatrem, leporins, aspirochlorine, ditryptophenaline, and aflavinines, supporting a role of rtfA as a global regulator of secondary metabolism. Heterologous complementation of an A. flavus rtfA deletion strain with rtfA homologs from A. nidulans or S. cerevisiae fully rescued the wild-type phenotype, indicating that these rtfA homologs are functionally conserved among these three species.IMPORTANCE In this study, the epigenetic global regulator rtfA, which encodes a putative RNA-Pol II transcription elongation factor-like protein, was characterized in the mycotoxigenic and opportunistic pathogen A. flavus Specifically, its involvement in A. flavus pathogenesis in plant and animal models was studied. Here, we show that rtfA positively regulates A. flavus virulence in both models. Furthermore, rtfA-dependent effects on factors necessary for successful invasion and colonization of host tissue by A. flavus were also assessed. Our study indicates that rtfA plays a role in A. flavus adherence to surfaces, hydrolytic activity, normal cell wall formation, and response to oxidative stress. This study also revealed a profound effect of rtfA on the metabolome of A. flavus, including the production of potent mycotoxins.
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Majumdar R, Minocha R, Lebar MD, Rajasekaran K, Long S, Carter-Wientjes C, Minocha S, Cary JW. Contribution of Maize Polyamine and Amino Acid Metabolism Toward Resistance Against Aspergillus flavus Infection and Aflatoxin Production. FRONTIERS IN PLANT SCIENCE 2019; 10:692. [PMID: 31178889 PMCID: PMC6543017 DOI: 10.3389/fpls.2019.00692] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 05/08/2019] [Indexed: 05/05/2023]
Abstract
Polyamines (PAs) are ubiquitous polycations found in plants and other organisms that are essential for growth, development, and resistance against abiotic and biotic stresses. The role of PAs in plant disease resistance depends on the relative abundance of higher PAs [spermidine (Spd), spermine (Spm)] vs. the diamine putrescine (Put) and PA catabolism. With respect to the pathogen, PAs are required to achieve successful pathogenesis of the host. Maize is an important food and feed crop, which is highly susceptible to Aspergillus flavus infection. Upon infection, the fungus produces carcinogenic aflatoxins and numerous other toxic secondary metabolites that adversely affect human health and crop value worldwide. To evaluate the role of PAs in aflatoxin resistance in maize, in vitro kernel infection assays were performed using maize lines that are susceptible (SC212) or resistant (TZAR102, MI82) to aflatoxin production. Results indicated significant induction of both PA biosynthetic and catabolic genes upon A. flavus infection. As compared to the susceptible line, the resistant maize lines showed higher basal expression of PA metabolism genes in mock-inoculated kernels that increased upon fungal infection. In general, increased biosynthesis and conversion of Put to Spd and Spm along with their increased catabolism was evident in the resistant lines vs. the susceptible line SC212. There were higher concentrations of amino acids such as glutamate (Glu), glutamine (Gln) and γ-aminobutyric acid (GABA) in SC212. The resistant lines were significantly lower in fungal load and aflatoxin production as compared to the susceptible line. The data presented here demonstrate an important role of PA metabolism in the resistance of maize to A. flavus colonization and aflatoxin contamination. These results provide future direction for the manipulation of PA metabolism in susceptible maize genotypes to improve aflatoxin resistance and overall stress tolerance.
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Affiliation(s)
- Rajtilak Majumdar
- Food and Feed Safety Research Unit, Southern Regional Research Center, United States Department of Agriculture, Agricultural Research Service, New Orleans, LA, United States
| | - Rakesh Minocha
- United States Department of Agriculture Forest Service, Northern Research Station, Durham, NH, United States
| | - Matthew D. Lebar
- Food and Feed Safety Research Unit, Southern Regional Research Center, United States Department of Agriculture, Agricultural Research Service, New Orleans, LA, United States
| | - Kanniah Rajasekaran
- Food and Feed Safety Research Unit, Southern Regional Research Center, United States Department of Agriculture, Agricultural Research Service, New Orleans, LA, United States
| | - Stephanie Long
- United States Department of Agriculture Forest Service, Northern Research Station, Durham, NH, United States
| | - Carol Carter-Wientjes
- Food and Feed Safety Research Unit, Southern Regional Research Center, United States Department of Agriculture, Agricultural Research Service, New Orleans, LA, United States
| | - Subhash Minocha
- Department of Biological Sciences, University of New Hampshire, Durham, NH, United States
| | - Jeffrey W. Cary
- Food and Feed Safety Research Unit, Southern Regional Research Center, United States Department of Agriculture, Agricultural Research Service, New Orleans, LA, United States
- *Correspondence: Jeffrey W. Cary,
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Ojiambo PS, Battilani P, Cary JW, Blum BH, Carbone I. Cultural and Genetic Approaches to Manage Aflatoxin Contamination: Recent Insights Provide Opportunities for Improved Control. PHYTOPATHOLOGY 2018; 108:1024-1037. [PMID: 29869954 DOI: 10.1094/phyto-04-18-0134-rvw] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Aspergillus flavus is a morphologically complex species that can produce the group of polyketide derived carcinogenic and mutagenic secondary metabolites, aflatoxins, as well as other secondary metabolites such as cyclopiazonic acid and aflatrem. Aflatoxin causes aflatoxicosis when aflatoxins are ingested through contaminated food and feed. In addition, aflatoxin contamination is a major problem, from both an economic and health aspect, in developing countries, especially Asia and Africa, where cereals and peanuts are important food crops. Earlier measures for control of A. flavus infection and consequent aflatoxin contamination centered on creating unfavorable environments for the pathogen and destroying contaminated products. While development of atoxigenic (nonaflatoxin producing) strains of A. flavus as viable commercial biocontrol agents has marked a unique advance for control of aflatoxin contamination, particularly in Africa, new insights into the biology and sexuality of A. flavus are now providing opportunities to design improved atoxigenic strains for sustainable biological control of aflatoxin. Further, progress in the use of molecular technologies such as incorporation of antifungal genes in the host and host-induced gene silencing, is providing knowledge that could be harnessed to develop germplasm that is resistant to infection by A. flavus and aflatoxin contamination. This review summarizes the substantial progress that has been made to understand the biology of A. flavus and mitigate aflatoxin contamination with emphasis on maize. Concepts developed to date can provide a basis for future research efforts on the sustainable management of aflatoxin contamination.
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Affiliation(s)
- Peter S Ojiambo
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
| | - Paola Battilani
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
| | - Jeffrey W Cary
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
| | - Burt H Blum
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
| | - Ignazio Carbone
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
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