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Scholthof KBG. The Greening of One Health: Plants, Pathogens, and the Environment. ANNUAL REVIEW OF PHYTOPATHOLOGY 2024; 62:401-421. [PMID: 38857537 DOI: 10.1146/annurev-phyto-121423-042102] [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: 06/12/2024]
Abstract
One Health has an aspirational goal of ensuring the health of humans, animals, plants, and the environment through transdisciplinary, collaborative research. At its essence, One Health addresses the human clash with Nature by formulating strategies to repair and restore a (globally) perturbed ecosystem. A more nuanced evaluation of humankind's impact on the environment (Nature, Earth, Gaia) would fully intercalate plants, plant pathogens, and beneficial plant microbes into One Health. Here, several examples point out how plants and plant microbes are keystones of One Health. Meaningful cross-pollination between plant, animal, and human health practitioners can drive discovery and application of innovative tools to address the many complex problems within the One Health framework.
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Affiliation(s)
- Karen-Beth G Scholthof
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas, USA;
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Sultana T, Malik K, Raja NI, Mashwani ZUR, Hameed A, Ullah R, Alqahtani AS, Sohail. Aflatoxins in Peanut ( Arachis hypogaea): Prevalence, Global Health Concern, and Management from an Innovative Nanotechnology Approach: A Mechanistic Repertoire and Future Direction. ACS OMEGA 2024; 9:25555-25574. [PMID: 38911815 PMCID: PMC11190918 DOI: 10.1021/acsomega.4c01316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 05/10/2024] [Accepted: 05/22/2024] [Indexed: 06/25/2024]
Abstract
Arachis hypogaea is the most significant oilseed nutritious legume crop in agricultural trade across the world. It is recognized as a valued crop for its contributions to nourishing food, as a cooking oil, and for meeting the protein needs of people who are unable to afford animal protein. Currently, its production, marketability, and consumption are hindered because of Aspergillus species infection that consequently contaminates the kernels with aflatoxins. Regarding health concerns, humans and animals are affected by acute and chronic aflatoxin toxicity and millions of people are at high risk of chronic levels. Most methods used to store peanuts are traditional and serve effectively for short-term storage. Now the question for long-term storage has been raised, and this promptly finds potential approaches to the issue. It is imperative to reduce the aflatoxin levels in peanuts to a permissible level by introducing detoxifying innovations. Most of the detoxification reports mention physical, chemical, and biological techniques. However, many current approaches are impractical because of time consumption, loss of nutritional quality, or weak detoxifying efficiency. Therefore, it is crucial to investigate practical, economical, and green methods to control Aspergillus flavus that address current global food security problems. Herein, a green and economically revolutionary way is a nanotechnology that has demonstrated its potential to connect farmers to markets, elevate international marketability, improve human and animal health conditions, and enhance food quality and safety by the management of fungal diseases. Due to the antimicrobial potential of nanoparticles, they act as nanofungicides and have an incredible role in the control of aflatoxins. Nanoparticles have ultrasmall sizes and therefore penetrate the fungal body and invade the pathogen machinery, leading to fungal cell death by ROS production, mutation in DNA, disruption of organelles, and membrane leakage. This is the first mechanistic overview that unveils a comprehensive insight into aflatoxin contamination in peanuts, its prevalence, health effects, and management in addition to nanotechnological interventions that serve as a triple defense approach to detoxify aflatoxins. The optimum use of nanofungicides ensures food safety and the development of goals, especially "zero hunger".
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Affiliation(s)
- Tahira Sultana
- Department
of Botany, PMAS, Arid Agriculture University
Rawalpindi, Rawalpindi 46000, Pakistan
| | - Khafsa Malik
- Department
of Botany, PMAS, Arid Agriculture University
Rawalpindi, Rawalpindi 46000, Pakistan
| | - Naveed Iqbal Raja
- Department
of Botany, PMAS, Arid Agriculture University
Rawalpindi, Rawalpindi 46000, Pakistan
| | - Zia-Ur-Rehman Mashwani
- Department
of Botany, PMAS, Arid Agriculture University
Rawalpindi, Rawalpindi 46000, Pakistan
| | - Asma Hameed
- Department
of Botany, PMAS, Arid Agriculture University
Rawalpindi, Rawalpindi 46000, Pakistan
| | - Riaz Ullah
- Medicinal
Aromatic and Poisonous Plants Research Center College of Pharmacy King Saud University, Riyadh 11451, Saudi Arabia
| | - Ali S. Alqahtani
- Medicinal
Aromatic and Poisonous Plants Research Center College of Pharmacy King Saud University, Riyadh 11451, Saudi Arabia
| | - Sohail
- College
of Bioscience and Biotechnology, Yangzhou
University, Yangzhou 225009, Jiangsu, China
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Llobregat B, González-Candelas L, Ballester AR. Exploring the Biocontrol Capability of Non-Mycotoxigenic Strains of Penicillium expansum. Toxins (Basel) 2024; 16:52. [PMID: 38251268 PMCID: PMC10820982 DOI: 10.3390/toxins16010052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/09/2024] [Accepted: 01/14/2024] [Indexed: 01/23/2024] Open
Abstract
Penicillium expansum is one the major postharvest pathogens of pome fruit during postharvest handling and storage. This fungus also produces patulin, which is a highly toxic mycotoxin that can contaminate infected fruits and their derived products and whose levels are regulated in many countries. In this study, we investigated the biocontrol potential of non-mycotoxigenic strains of Penicillium expansum against a mycotoxigenic strain. We analyzed the competitive behavior of two knockout mutants that were unable to produce patulin. The first mutant (∆patK) involved the deletion of the patK gene, which is the initial gene in patulin biosynthesis. The second mutant (∆veA) involved the deletion of veA, which is a global regulator of primary and secondary metabolism. At the phenotypic level, the ∆patK mutant exhibited similar phenotypic characteristics to the wild-type strain. In contrast, the ∆veA mutant displayed altered growth characteristics compared with the wild type, including reduced conidiation and abnormal conidiophores. Neither mutant produced patulin under the tested conditions. Under various stress conditions, the ∆veA mutants exhibited reduced growth and conidiation when exposed to stressors, including cell membrane stress, oxidative stress, osmotic stress, and different pH values. However, no significant changes were observed in the ∆patK mutant. In competitive growth experiments, the presence of non-mycotoxigenic strains reduced the population of the wild-type strain during in vitro growth. Furthermore, the addition of either of the non-mycotoxigenic strains resulted in a significant decrease in patulin levels. Overall, our results suggest the potential use of non-mycotoxigenic mutants, particularly ∆patK mutants, as biocontrol agents to reduce patulin contamination in food and feed.
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Affiliation(s)
| | | | - Ana-Rosa Ballester
- Instituto de Agroquímica y Tecnología de Alimentos (IATA), CSIC, Calle Catedrático Agustín Escardino 7, 46980 Paterna, Spain; (B.L.); (L.G.-C.)
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Ortega-Beltran A, Bandyopadhyay R. Aflatoxin biocontrol in practice requires a multidisciplinary, long-term approach. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2023. [DOI: 10.3389/fsufs.2023.1110964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
One of the most elusive food safety problems is the contamination of staple crops with the highly carcinogenic aflatoxins produced by Aspergillus section Flavi fungi. Governments, farmers, institutions, consumers, and companies demand aflatoxin solutions. Many aflatoxin management technologies exist, but their real-life use and effectiveness is determined by diverse factors. Biocontrol products based on atoxigenic isolates of A. flavus can effectively reduce aflatoxins from field to fork. However, development, testing, and registration of this technology is a laborious process. Further, several barriers prevent the sustainable use of biocontrol products. There are challenges to have the products accepted, to make them available at scale and develop mechanisms for farmers to buy them, to have the products correctly used, to demonstrate their value, and to link farmers to buyers of aflatoxin-safe crops. Developing an effective aflatoxin management technology is the first, major step. The second one, perhaps more complicated and unfortunately seldomly discussed, is to develop mechanisms to have it used at scale, sustainably, and converged with other complementary technologies. Here, challenges and actions to scale the aflatoxin biocontrol technology in several countries in sub-Saharan Africa are described with a view to facilitating aflatoxin management efforts in Africa and beyond.
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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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Comprehensive Review of Aflatoxin Contamination, Impact on Health and Food Security, and Management Strategies in Pakistan. Toxins (Basel) 2022; 14:toxins14120845. [PMID: 36548742 PMCID: PMC9781569 DOI: 10.3390/toxins14120845] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/22/2022] [Accepted: 11/26/2022] [Indexed: 12/05/2022] Open
Abstract
Aflatoxins (AFs) are the most important toxic, mutagenic, and carcinogenic fungal toxins that routinely contaminate food and feed. While more than 20 AFs have been identified to date, aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2), and M1 (AFM1) are the most common. Over 25 species of Aspergillus have been shown to produce AFs, with Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius being the most important and well-known AF-producing fungi. These ubiquitous molds can propagate on agricultural commodities to produce AFs in fields and during harvesting, processing, transportation, and storage. Countries with warmer climates and that produce foods susceptible to AF contamination shoulder a substantial portion of the global AF burden. Pakistan's warm climate promotes the growth of toxigenic fungi, resulting in frequent AF contamination of human foods and animal feeds. The potential for contamination in Pakistan is exacerbated by improper storage conditions and a lack of regulatory limits and enforcement mechanisms. High levels of AFs in common commodities produced in Pakistan are a major food safety problem, posing serious health risks to the population. Furthermore, aflatoxin contamination contributes to economic losses by limiting exports of these commodities. In this review, recent information regarding the fungal producers of AFs, prevalence of AF contamination of foods and feed, current regulations, and AF prevention and removal strategies are summarized, with a major focus on Pakistan.
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Characterization of the Aspergillus flavus Population from Highly Aflatoxin-Contaminated Corn in the United States. Toxins (Basel) 2022; 14:toxins14110755. [PMID: 36356005 PMCID: PMC9698142 DOI: 10.3390/toxins14110755] [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: 09/30/2022] [Revised: 10/23/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022] Open
Abstract
Aflatoxin contamination of corn is a major threat to the safe food and feed. The United States Federal Grain Inspection Service (FGIS) monitors commercial grain shipments for the presence of aflatoxin. A total of 146 Aspergillus flavus were isolated from 29 highly contaminated grain samples to characterize the visual phenotypes, aflatoxin-producing potential, and genotypes to explore the etiological cause of high aflatoxin contamination of US corn. Five of the isolates had reduced sensitivity (43-49% resistant) to the fungicide azoxystrobin, with the remainder all being over 50% resistant to azoxystrobin at the discriminating dose of 2.5 µg/mL. Only six isolates of the highly aflatoxigenic S morphotype were found, and 48 isolates were non-aflatoxigenic. Analysis of the mating type locus revealed 45% MAT 1-1 and 55% MAT 1-2. The A. flavus population originating from the highly aflatoxin contaminated grain samples was compared to a randomly selected subset of isolates originating from commercial corn samples with typical levels of aflatoxin contamination (average < 50 ppb). Use of simple sequence repeat (SSR) genotyping followed by principal component analysis (PCoA) revealed a similar pattern of genotypic distribution in the two populations, but greater diversity in the FGIS-derived population. The noticeable difference between the two populations was that genotypes identical to strain NRRL 21882, the active component of the aflatoxin biocontrol product Afla-Guard™, were ten times more common in the commercial corn population of A. flavus compared to the population from the high-aflatoxin corn samples. The other similarities between the two populations suggest that high aflatoxin concentrations in corn grain are generally the result of infection with common A. flavus genotypes.
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Rahman MAH, Selamat J, Samsudin NIP, Shaari K, Mahror N, John JM. Antagonism of nonaflatoxigenic Aspergillus flavus isolated from peanuts against aflatoxigenic A. flavus growth and aflatoxin B 1 production in vitro. Food Sci Nutr 2022; 10:3993-4002. [PMID: 36348788 PMCID: PMC9632215 DOI: 10.1002/fsn3.2995] [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: 09/19/2021] [Revised: 07/05/2022] [Accepted: 07/08/2022] [Indexed: 11/12/2022] Open
Abstract
Aspergillus section Flavi constitutes several species of opportunistic fungi, notable among them are A. flavus and A. parasiticus, capable of surviving harsh conditions and colonizing a wide range of agricultural products pre- and postharvest. Physical and chemical control methods are widely applied in order to mitigate the invasion of A. flavus in crops. However, physical control is not suitable for large scale and chemical control often leads to environmental pollution, whereas biological control offers a safer, environmentally friendly, and economical alternative. The present study aimed to investigate the antagonism of several non-aflatoxigenic A. flavus strains against the aflatoxigenic ones in vitro (semisynthetic peanut growth medium; MPA) in terms of colony growth rate and AFB1 inhibition. Different peanut concentrations were used to obtain the optimum peanut concentration in the formulated growth medium. A dual culture assay was performed to assess the antagonism of nonaflatoxigenic strains against the aflatoxigenic ones. Results revealed that 9% MPA exhibited the highest growth and AFB1 inhibition by nonaflatoxigenic strains. It was also found that different nonaflatoxigenic strains exhibited different antagonism against the aflatoxigenic ones which ranged from 11.09 ± 0.65% to 14.06 ± 0.14% for growth inhibition, and 53.97 ± 2.46% to 72.64 ± 4.54% for AFB1 inhibition. This variability could be due to the difference in antagonistic metabolites produced by different nonaflatoxigenic strains assessed in the present study. Metabolomics study to ascertain the specific metabolites that conferred the growth and aflatoxin inhibition is ongoing.
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Affiliation(s)
- Mohd Azuar Hamizan Rahman
- Department of Food Science, Faculty of Food Science and TechnologyUniversiti Putra MalaysiaSerdangMalaysia
| | - Jinap Selamat
- Department of Food Science, Faculty of Food Science and TechnologyUniversiti Putra MalaysiaSerdangMalaysia
- Laboratory of Food Safety and Food Integrity, Institute of Tropical Agriculture and Food SecurityUniversiti Putra MalaysiaSerdangMalaysia
| | - Nik Iskandar Putra Samsudin
- Department of Food Science, Faculty of Food Science and TechnologyUniversiti Putra MalaysiaSerdangMalaysia
- Laboratory of Food Safety and Food Integrity, Institute of Tropical Agriculture and Food SecurityUniversiti Putra MalaysiaSerdangMalaysia
| | - Khozirah Shaari
- Department of Chemistry, Faculty of ScienceUniversiti Putra MalaysiaSerdangMalaysia
- Natural Medicines and Product Research Laboratory, Institute of BioscienceUniversiti Putra MalaysiaSerdangMalaysia
| | - Norlia Mahror
- Food Technology Division, School of Industrial TechnologyUniversiti Sains MalaysiaPulau PinangMalaysia
| | - Joshua Mark John
- Laboratory of Food Safety and Food Integrity, Institute of Tropical Agriculture and Food SecurityUniversiti Putra MalaysiaSerdangMalaysia
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Ochratoxin A Defective Aspergillus carbonarius Mutants as Potential Biocontrol Agents. Toxins (Basel) 2022; 14:toxins14110745. [PMID: 36355995 PMCID: PMC9695793 DOI: 10.3390/toxins14110745] [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: 10/03/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022] Open
Abstract
Aspergillus carbonarius is one of the main species responsible for wine, coffee and cocoa toxin contamination. The main mycotoxin produced by this fungus, ochratoxin A (OTA), is a secondary metabolite categorized as a possible carcinogen because of its significant nephrotoxicity and immunosuppressive effects. A polyketide synthase gene (otaA) encodes the first enzyme in the OTA biosynthetic pathway. It is known that the filamentous fungi, growth, development and production of secondary metabolites are interconnected processes governed by global regulatory factors whose encoding genes are generally located outside the gene clusters involved in the biosynthesis of each secondary metabolite, such as the veA gene, which forms part of the VELVET complex. Different fungal strains compete for nutrients and space when they infect their hosts, and safer non-mycotoxigenic strains may be able to outcompete mycotoxigenic strains during colonization. To determine the possible utility of biopesticides based on the competitive exclusion of mycotoxigenic strains by non-toxigenic ones, we used A. carbonarius ΔotaA and ΔveA knockout mutants. Our results showed that during both in vitro growth and infection of grapes, non-mycotoxigenic strains could outcompete the wild-type strain. Additionally, the introduction of the non-mycotoxigenic strain led to a drastic decrease in OTA during both in vitro growth and infection of grapes.
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Molo MS, White JB, Cornish V, Gell RM, Baars O, Singh R, Carbone MA, Isakeit T, Wise KA, Woloshuk CP, Bluhm BH, Horn BW, Heiniger RW, Carbone I. Asymmetrical lineage introgression and recombination in populations of Aspergillus flavus: Implications for biological control. PLoS One 2022; 17:e0276556. [PMID: 36301851 PMCID: PMC9620740 DOI: 10.1371/journal.pone.0276556] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 10/08/2022] [Indexed: 11/23/2022] Open
Abstract
Aspergillus flavus is an agriculturally important fungus that causes ear rot of maize and produces aflatoxins, of which B1 is the most carcinogenic naturally-produced compound. In the US, the management of aflatoxins includes the deployment of biological control agents that comprise two nonaflatoxigenic A. flavus strains, either Afla-Guard (member of lineage IB) or AF36 (lineage IC). We used genotyping-by-sequencing to examine the influence of both biocontrol agents on native populations of A. flavus in cornfields in Texas, North Carolina, Arkansas, and Indiana. This study examined up to 27,529 single-nucleotide polymorphisms (SNPs) in a total of 815 A. flavus isolates, and 353 genome-wide haplotypes sampled before biocontrol application, three months after biocontrol application, and up to three years after initial application. Here, we report that the two distinct A. flavus evolutionary lineages IB and IC differ significantly in their frequency distributions across states. We provide evidence of increased unidirectional gene flow from lineage IB into IC, inferred to be due to the applied Afla-Guard biocontrol strain. Genetic exchange and recombination of biocontrol strains with native strains was detected in as little as three months after biocontrol application and up to one and three years later. There was limited inter-lineage migration in the untreated fields. These findings suggest that biocontrol products that include strains from lineage IB offer the greatest potential for sustained reductions in aflatoxin levels over several years. This knowledge has important implications for developing new biocontrol strategies.
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Affiliation(s)
- Megan S. Molo
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
| | - James B. White
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
| | - Vicki Cornish
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
| | - Richard M. Gell
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
- Program of Genetics, North Carolina State University, Raleigh, North
Carolina, United States of America
| | - Oliver Baars
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
| | - Rakhi Singh
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
| | - Mary Anna Carbone
- Center for Integrated Fungal Research and Department of Plant and
Microbial Biology, North Carolina State University, Raleigh, NC, United States
of America
| | - Thomas Isakeit
- Department of Plant Pathology and Microbiology, Texas AgriLife Extension
Service, Texas A&M University, College Station, TX, United States of
America
| | - Kiersten A. Wise
- Department of Plant Pathology, University of Kentucky, Princeton, KY,
United States of America
| | - Charles P. Woloshuk
- Department of Plant Pathology and Botany, Purdue University, West
Lafayette, IN, United States of America
| | - Burton H. Bluhm
- University of Arkansas Division of Agriculture, Department of Entomology
and Plant Pathology, Fayetteville, AR, United States of
America
| | - Bruce W. Horn
- United States Department of Agriculture, Agriculture Research Service,
Dawson, GA, United States of America
| | - Ron W. Heiniger
- Department of Crop and Soil Sciences, North Carolina State University,
Raleigh, NC, United States of America
| | - Ignazio Carbone
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
- Program of Genetics, North Carolina State University, Raleigh, North
Carolina, United States of America
- * E-mail:
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Mahuku G, Mauro A, Pallangyo B, Nsami E, Boni S, Koyano E, Mponda O, Ortega-Beltran A, Atehnkeng J, Aquiline F, Samuel R, Njela J, Cotty P, Bandyopadhyay R. Atoxigenic-based technology for biocontrol of aflatoxin in maize and groundnuts for Tanzania. WORLD MYCOTOXIN J 2022. [DOI: 10.3920/wmj2021.2758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Application of biocontrol products containing atoxigenic isolates of Aspergillus flavus to reduce aflatoxin content in crops is an effective strategy for managing aflatoxin in several regions throughout the world. We report the development and validation of two aflatoxin biocontrol products, Aflasafe TZ01 and Aflasafe TZ02, for use in maize and groundnut in Tanzania, a country frequently affected by aflatoxin contamination. Each product contains four atoxigenic A. flavus genotypes native and widely distributed in Tanzania. Efficacy tests on maize and groundnut were conducted over two years and in four regions of Tanzania where aflatoxin contamination is prevalent. Application of both products significantly (P<0.05) reduced aflatoxin levels in maize and groundnut in both years and in all districts. No differences were observed in total Aspergillus section Flavi population in treated and untreated fields, revealing that application of the biocontrol products do not alter overall Aspergillus populations in the environment. The results indicate that both products are effective tools for aflatoxin mitigation in groundnut and maize. The products were officially registered in 2018. Currently, there are scale-out and-up efforts of aflatoxin biocontrol products in Tanzania through a private sector company that is making the products available to farmers. Protecting maize and groundnut from aflatoxin contamination in Tanzania can result in health, income, and trade benefits.
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Affiliation(s)
- G. Mahuku
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
| | - A. Mauro
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
| | - B. Pallangyo
- Plant Health Services, Ministry of Agriculture, P.O. Box 2182, Dodoma, Tanzania
| | - E. Nsami
- National Biological Control Center, P.O. Box 30031, Kibaha, Tanzania
| | - S.B. Boni
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
- World Vegetable Center, Eastern and Southern Africa, P.O. Box 10, Duluti, Arusha, Tanzania
| | - E. Koyano
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
| | - O. Mponda
- Department of Research, Ministry of Agriculture, Livestock and Fisheries, P.O. Box 9192, Dar es Salaam, Tanzania
| | - A. Ortega-Beltran
- IITA Headquarters, PMB 5320, Oyo Road, Ibadan 200001, Oyo State, Nigeria
| | - J. Atehnkeng
- IITA Headquarters, PMB 5320, Oyo Road, Ibadan 200001, Oyo State, Nigeria
| | - F. Aquiline
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
| | - R. Samuel
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
| | - J. Njela
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
| | - P.J. Cotty
- USDA-ARS, 416 West Congress Street, Tucson, AZ 85701, USA
| | - R. Bandyopadhyay
- IITA Headquarters, PMB 5320, Oyo Road, Ibadan 200001, Oyo State, Nigeria
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Spadola G, Giannelli G, Magagnoli S, Lanzoni A, Albertini M, Nicoli R, Ferrari R, Burgio G, Restivo FM, Degola F. Validation and Ecological Niche Investigation of a New Fungal Intraspecific Competitor as a Biocontrol Agent for the Sustainable Containment of Aflatoxins on Maize Fields. J Fungi (Basel) 2022; 8:jof8050425. [PMID: 35628681 PMCID: PMC9147465 DOI: 10.3390/jof8050425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/09/2022] [Accepted: 04/20/2022] [Indexed: 02/01/2023] Open
Abstract
Crop yield and plant products quality are directly or indirectly affected by climate alterations. Adverse climatic conditions often promote the occurrence of different abiotic stresses, which can reduce or enhance the susceptibility to pests or pathogens. Aflatoxin producing fungi, in particular, whose diffusion and deleterious consequences on cereals commodities have been demonstrated to highly depend on the temperature and humidity conditions that threaten increasingly larger areas. Biological methods using intraspecific competitors to prevent fungal development and/or toxin production at the pre-harvest level are particularly promising, even if their efficacy could be affected by the ecological interaction within the resident microbial population. A previously characterized Aspergillus flavus atoxigenic strain was applied in two maize fields to validate its effectiveness as a biocontrol agent against aflatoxin contamination. At one month post-application, at the harvest stage, its persistence within the A. flavus population colonizing the maize kernels in the treated area was assessed, and its efficacy was compared in vitro with a representation of the isolated atoxigenic population. Results proved that our fungal competitor contained the aflatoxin level on maize grains as successfully as a traditional chemical strategy, even if representing less than 30% of the atoxigenic strains re-isolated, and achieved the best performance (in terms of bio-competitive potential) concerning endogenous atoxigenic isolates.
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Affiliation(s)
- Giorgio Spadola
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (G.S.); (G.G.); (F.M.R.)
| | - Gianluigi Giannelli
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (G.S.); (G.G.); (F.M.R.)
| | - Serena Magagnoli
- Department of Agricultural and Food Sciences (DISTAL), University of Bologna, 40127 Bologna, Italy; (S.M.); (A.L.); (G.B.)
| | - Alberto Lanzoni
- Department of Agricultural and Food Sciences (DISTAL), University of Bologna, 40127 Bologna, Italy; (S.M.); (A.L.); (G.B.)
| | - Marco Albertini
- Agrites S.r.l., 40057 Granarolo dell’Emilia, Italy; (M.A.); (R.N.)
| | - Riccardo Nicoli
- Agrites S.r.l., 40057 Granarolo dell’Emilia, Italy; (M.A.); (R.N.)
| | - Roberto Ferrari
- Centro Agricoltura Ambiente “Giorgio Nicoli” S.r.l., 40014 Crevalcore, Italy;
| | - Giovanni Burgio
- Department of Agricultural and Food Sciences (DISTAL), University of Bologna, 40127 Bologna, Italy; (S.M.); (A.L.); (G.B.)
| | - Francesco M. Restivo
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (G.S.); (G.G.); (F.M.R.)
| | - Francesca Degola
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (G.S.); (G.G.); (F.M.R.)
- Correspondence:
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13
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May G, Shaw RG, Geyer CJ, Eck DJ. Do Interactions among Microbial Symbionts Cause Selection for Greater Pathogen Virulence? Am Nat 2022; 199:252-265. [DOI: 10.1086/717679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Georgiana May
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, Minnesota 55108
| | - Ruth G. Shaw
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, Minnesota 55108
| | - Charles J. Geyer
- School of Statistics, University of Minnesota, Minneapolis, Minnesota 55455
| | - Daniel J. Eck
- Department of Statistics, University of Illinois, Champaign, Illinois 61820
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14
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Development of sexual structures influences metabolomic and transcriptomic profiles in Aspergillus flavus. Fungal Biol 2022; 126:187-200. [DOI: 10.1016/j.funbio.2022.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 01/02/2023]
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15
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Banfalvi G. Janus-Faced Molecules against Plant Pathogenic Fungi. Int J Mol Sci 2021; 22:12323. [PMID: 34830204 PMCID: PMC8623416 DOI: 10.3390/ijms222212323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/08/2021] [Accepted: 11/11/2021] [Indexed: 11/16/2022] Open
Abstract
The high cytotoxicity of the secondary metabolites of mycotoxins is capable of killing microbes and tumour cells alike, similarly to the genotoxic effect characteristic of Janus-faced molecules. The "double-edged sword" effect of several cytotoxins is known, and these agents have, therefore, been utilized only reluctantly against fungal infections. In this review, consideration was given to (a) toxins that could be used against plant and human pathogens, (b) animal models that measure the effect of antifungal agents, (c) known antifungal agents that have been described and efficiently prevent the growth of fungal cells, and (d) the chemical interactions that are characteristic of antifungal agents. The utilization of apoptotic effects against tumour growth by agents that, at the same time, induce mutations may raise ethical issues. Nevertheless, it deserves consideration despite the mutagenic impact of Janus-faced molecules for those patients who suffer from plant pathogenic fungal infections and are older than their fertility age, in the same way that the short-term cytotoxicity of cancer treatment is favoured over the long-term mutagenic effect.
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Affiliation(s)
- Gaspar Banfalvi
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, 1 Egyetem Square, 4010 Debrecen, Hungary
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16
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Pickova D, Ostry V, Toman J, Malir F. Aflatoxins: History, Significant Milestones, Recent Data on Their Toxicity and Ways to Mitigation. Toxins (Basel) 2021; 13:399. [PMID: 34205163 PMCID: PMC8227755 DOI: 10.3390/toxins13060399] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/04/2021] [Accepted: 06/02/2021] [Indexed: 02/07/2023] Open
Abstract
In the early 1960s the discovery of aflatoxins began when a total of 100,000 turkey poults died by hitherto unknown turkey "X" disease in England. The disease was associated with Brazilian groundnut meal affected by Aspergillus flavus. The toxin was named Aspergillus flavus toxin-aflatoxin. From the point of view of agriculture, aflatoxins show the utmost importance. Until now, a total of 20 aflatoxins have been described, with B1, B2, G1, and G2 aflatoxins being the most significant. Contamination by aflatoxins is a global health problem. Aflatoxins pose acutely toxic, teratogenic, immunosuppressive, carcinogenic, and teratogenic effects. Besides food insecurity and human health, aflatoxins affect humanity at different levels, such as social, economical, and political. Great emphasis is placed on aflatoxin mitigation using biocontrol methods. Thus, this review is focused on aflatoxins in terms of historical development, the principal milestones of aflatoxin research, and recent data on their toxicity and different ways of mitigation.
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Affiliation(s)
- Darina Pickova
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (J.T.); (F.M.)
| | - Vladimir Ostry
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (J.T.); (F.M.)
- Center for Health, Nutrition and Food in Brno, National Institute of Public Health in Prague, Palackeho 3a, CZ-61242 Brno, Czech Republic
| | - Jakub Toman
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (J.T.); (F.M.)
| | - Frantisek Malir
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (J.T.); (F.M.)
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Khan R, Ghazali FM, Mahyudin NA, Samsudin NIP. Biocontrol of Aflatoxins Using Non-Aflatoxigenic Aspergillus flavus: A Literature Review. J Fungi (Basel) 2021; 7:jof7050381. [PMID: 34066260 PMCID: PMC8151999 DOI: 10.3390/jof7050381] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/07/2021] [Accepted: 05/08/2021] [Indexed: 02/06/2023] Open
Abstract
Aflatoxins (AFs) are mycotoxins, predominantly produced by Aspergillus flavus, A. parasiticus, A. nomius, and A. pseudotamarii. AFs are carcinogenic compounds causing liver cancer in humans and animals. Physical and biological factors significantly affect AF production during the pre-and post-harvest time. Several methodologies have been developed to control AF contamination, yet; they are usually expensive and unfriendly to the environment. Consequently, interest in using biocontrol agents has increased, as they are convenient, advanced, and friendly to the environment. Using non-aflatoxigenic strains of A. flavus (AF−) as biocontrol agents is the most promising method to control AFs’ contamination in cereal crops. AF− strains cannot produce AFs due to the absence of polyketide synthase genes or genetic mutation. AF− strains competitively exclude the AF+ strains in the field, giving an extra advantage to the stored grains. Several microbiological, molecular, and field-based approaches have been used to select a suitable biocontrol agent. The effectiveness of biocontrol agents in controlling AF contamination could reach up to 99.3%. Optimal inoculum rate and a perfect time of application are critical factors influencing the efficacy of biocontrol agents.
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Affiliation(s)
- Rahim Khan
- Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang 43400, Malaysia; (R.K.); (N.I.P.S.)
| | - Farinazleen Mohamad Ghazali
- Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang 43400, Malaysia; (R.K.); (N.I.P.S.)
- Correspondence: ; Tel.: +60-12219-8912
| | - Nor Ainy Mahyudin
- Department of Food Service and Management, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang 43400, Malaysia;
- Laboratory of Halal Science Research, Halal Products Research Institute, Universiti Putra Malaysia, Serdang 43400, Malaysia
| | - Nik Iskandar Putra Samsudin
- Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang 43400, Malaysia; (R.K.); (N.I.P.S.)
- Laboratory of Food Safety and Food Integrity, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang 43400, Malaysia
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18
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Peles F, Sipos P, Kovács S, Győri Z, Pócsi I, Pusztahelyi T. Biological Control and Mitigation of Aflatoxin Contamination in Commodities. Toxins (Basel) 2021; 13:toxins13020104. [PMID: 33535580 PMCID: PMC7912779 DOI: 10.3390/toxins13020104] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/23/2021] [Accepted: 01/29/2021] [Indexed: 11/16/2022] Open
Abstract
Aflatoxins (AFs) are toxic secondary metabolites produced mostly by Aspergillus species. AF contamination entering the feed and food chain has been a crucial long-term issue for veterinarians, medicals, agroindustry experts, and researchers working in this field. Although different (physical, chemical, and biological) technologies have been developed, tested, and employed to mitigate the detrimental effects of mycotoxins, including AFs, universal methods are still not available to reduce AF levels in feed and food in the last decades. Possible biological control by bacteria, yeasts, and fungi, their excretes, the role of the ruminal degradation, pre-harvest biocontrol by competitive exclusion or biofungicides, and post-harvest technologies and practices based on biological agents currently used to alleviate the toxic effects of AFs are collected in this review. Pre-harvest biocontrol technologies can give us the greatest opportunity to reduce AF production on the spot. Together with post-harvest applications of bacteria or fungal cultures, these technologies can help us strictly reduce AF contamination without synthetic chemicals.
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Affiliation(s)
- Ferenc Peles
- Institute of Food Science, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Böszörményi str. 138, H-4032 Debrecen, Hungary;
| | - Péter Sipos
- Institute of Nutrition, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Böszörményi str. 138, H-4032 Debrecen, Hungary; (P.S.); (Z.G.)
| | - Szilvia Kovács
- Central Laboratory of Agricultural and Food Products, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Böszörményi str. 138, H-4032 Debrecen, Hungary;
| | - Zoltán Győri
- Institute of Nutrition, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Böszörményi str. 138, H-4032 Debrecen, Hungary; (P.S.); (Z.G.)
| | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Egyetem Square 1, H-4032 Debrecen, Hungary;
| | - Tünde Pusztahelyi
- Central Laboratory of Agricultural and Food Products, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Böszörményi str. 138, H-4032 Debrecen, Hungary;
- Correspondence: ; Tel.: +36-20-210-9491
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19
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Moore GG. Practical considerations will ensure the continued success of pre-harvest biocontrol using non-aflatoxigenic Aspergillus flavus strains. Crit Rev Food Sci Nutr 2021; 62:4208-4225. [PMID: 33506687 DOI: 10.1080/10408398.2021.1873731] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
There is an important reason for the accelerated use of non-aflatoxigenic Aspergillus flavus to mitigate pre-harvest aflatoxin contamination… it effectively addresses the imperative need for safer food and feed. Now that we have decades of proof of the effectiveness of A. flavus as biocontrol, it is time to improve several aspects of this strategy. If we are to continue relying heavily on this form of aflatoxin mitigation, there are considerations we must acknowledge, and actions we must take, to ensure that we are best wielding this strategy to our advantage. These include its: (1) potential to produce other mycotoxins, (2) persistence in the field in light of several ecological factors, (3) its reproductive and genetic stability, (4) the mechanism(s) employed that allow it to elicit control over aflatoxigenic strains and species of agricultural importance and (5) supplemental alternatives that increase its effectiveness. There is a need to be consistent, practical and thoughtful when it comes to implementing this method of mycotoxin mitigation since these fungi are living organisms that have been adapting, evolving and surviving on this planet for tens-of-millions of years. This document will serve as a critical review of the literature regarding pre-harvest A. flavus biocontrol and will discuss opportunities for improvements.
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Affiliation(s)
- Geromy G Moore
- United States Department of Agriculture, Agricultural Research Service, New Orleans, USA
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20
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Gell RM, Horn BW, Carbone I. Genetic map and heritability of Aspergillus flavus. Fungal Genet Biol 2020; 144:103478. [PMID: 33059038 DOI: 10.1016/j.fgb.2020.103478] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 07/31/2020] [Accepted: 10/07/2020] [Indexed: 12/30/2022]
Abstract
The carcinogenic aflatoxins are a human health concern as well as an economic burden to corn, peanut and other crops grown within the United States and globally. Aflatoxins are produced by fungi species in Aspergillus section Flavi, primarily Aspergillus flavus. Though previously thought of as only asexual, A. flavus has recently been found to undergo sexual reproduction both in laboratory crosses and in the field. To elucidate the consequences of genetic exchange through a single generation of the sexual cycle within A. flavus, we constructed genetic maps based on three mapping populations, each composed of the parental strains and approximately 70 F1 progeny. Genome-wide data using double digest Restriction Associated DNA sequencing identified 496, 811, and 576 significant polymorphisms differentiating parents across eight linkage groups; these polymorphisms served as markers. Average spacing between marker loci was 3.1, 2.1, and 3.5 map units and overall map length was 1504.4, 1669.2, and 2001.3 cM. Recombination was non-randomly distributed across chromosomes with an average rate of recombination of about 46.81 cM per Mbp. We showed inheritance of mitochondrial loci from the sclerotial (female) parent in crosses, whereas nuclear loci showed a 1:1 segregation ratio from both parents. The linkage map will be useful in QTL analyses to identify traits that increase sexual fertility in A. flavus and modulate aflatoxin production, both of which have significant implications for sustainable reduction of aflatoxin contamination using biological control agents.
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Affiliation(s)
- Richard M Gell
- Center for Integrated Fungal Research, Program of Genetics, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, USA
| | - Bruce W Horn
- National Peanut Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Dawson, GA, USA
| | - Ignazio Carbone
- Center for Integrated Fungal Research, Program of Genetics, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, USA.
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21
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Drott MT, Satterlee TR, Skerker JM, Pfannenstiel BT, Glass NL, Keller NP, Milgroom MG. The Frequency of Sex: Population Genomics Reveals Differences in Recombination and Population Structure of the Aflatoxin-Producing Fungus Aspergillus flavus. mBio 2020; 11:e00963-20. [PMID: 32665272 PMCID: PMC7360929 DOI: 10.1128/mbio.00963-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/18/2020] [Indexed: 11/20/2022] Open
Abstract
The apparent rarity of sex in many fungal species has raised questions about how much sex is needed to purge deleterious mutations and how differences in frequency of sex impact fungal evolution. We sought to determine how differences in the extent of recombination between populations of Aspergillus flavus impact the evolution of genes associated with the synthesis of aflatoxin, a notoriously potent carcinogen. We sequenced the genomes of, and quantified aflatoxin production in, 94 isolates of A. flavus sampled from seven states in eastern and central latitudinal transects of the United States. The overall population is subdivided into three genetically differentiated populations (A, B, and C) that differ greatly in their extent of recombination, diversity, and aflatoxin-producing ability. Estimates of the number of recombination events and linkage disequilibrium decay suggest relatively frequent sex only in population A. Population B is sympatric with population A but produces significantly less aflatoxin and is the only population where the inability of nonaflatoxigenic isolates to produce aflatoxin was explained by multiple gene deletions. Population expansion evident in population B suggests a recent introduction or range expansion. Population C is largely nonaflatoxigenic and restricted mainly to northern sampling locations through restricted migration and/or selection. Despite differences in the number and type of mutations in the aflatoxin gene cluster, codon optimization and site frequency differences in synonymous and nonsynonymous mutations suggest that low levels of recombination in some A. flavus populations are sufficient to purge deleterious mutations.IMPORTANCE Differences in the relative frequencies of sexual and asexual reproduction have profound implications for the accumulation of deleterious mutations (Muller's ratchet), but little is known about how these differences impact the evolution of ecologically important phenotypes. Aspergillus flavus is the main producer of aflatoxin, a notoriously potent carcinogen that often contaminates food. We investigated if differences in the levels of production of aflatoxin by A. flavus could be explained by the accumulation of deleterious mutations due to a lack of recombination. Despite differences in the extent of recombination, variation in aflatoxin production is better explained by the demography and history of specific populations and may suggest important differences in the ecological roles of aflatoxin among populations. Furthermore, the association of aflatoxin production and populations provides a means of predicting the risk of aflatoxin contamination by determining the frequencies of isolates from low- and high-production populations.
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Affiliation(s)
- Milton T Drott
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Tatum R Satterlee
- Department of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jeffrey M Skerker
- Innovative Genomics Institute, The University of California, Berkeley, California, USA
| | | | - N Louise Glass
- Innovative Genomics Institute, The University of California, Berkeley, California, USA
- Department of Plant and Microbial Biology, The University of California, Berkeley, California, USA
- Environmental Genomics and Systems Biology, The Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Michael G Milgroom
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, New York, USA
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22
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Abstract
AbstractA microbiome rife with enemies of the host should cause selection for defensive traits in symbionts, yet such complex environments are also predicted to select for greater symbiont virulence. Why then do we so often observe defensive mutualists that protect hosts while causing little to no damage? To address this question, we build a symbiont-centered model that incorporates the evolution of two independent symbiont traits: defense and virulence. Virulence is modeled as a continuous trait spanning parasitism (positive virulence) and mutualism (negative virulence), thus accounting for the entire range of direct effects that symbionts have on host mortality. Defense is modeled as a continuous trait that ameliorates the costs to the host associated with infection by a deleterious parasite. We show that the evolution of increased defense in one symbiont may lead to the evolution of lower virulence in both symbionts and even facilitate pathogens evolving to mutualism. However, results are context dependent, and when defensive traits are costly, the evolution of greater defense may also lead to the evolution of greater virulence, breaking the common expectation that defensive symbionts are necessarily mutualists toward the host.
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23
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Ahmad KS, Gul P. Fungicide isopyrazam degradative response toward extrinsically added fungal and bacterial strains. J Basic Microbiol 2020; 60:484-493. [PMID: 32314411 DOI: 10.1002/jobm.201900687] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/25/2020] [Accepted: 03/28/2020] [Indexed: 12/20/2022]
Abstract
The current research is a pioneer in the evaluation of isopyrazam biodegradation, which has been performed utilizing soil-isolated microbes. Biodisintegrative assays of pure fungal strains, namely Aspergillus flavus (AF), Penicillium chrysogenum (PC), Aspergillus niger (AN), Aspergillus terreus (AT), and Aspergillus fumigatus (AFu), and bacterial strains, namely Xanthomonas axonopodis (XA) and Pseudomonas syringae (PS), were utilized. Initial isopyrazam concentration (10 mg/L) was prepared with an individual microbial suspension and monitored for 35 days. Isopyrazam biotransformation was analyzed quantitatively and qualitatively by UV-visible spectrophotometery and gas chromatography-mass spectroscopy. P. syringae (R2 = 0.90) and X. axonopodis (R2 = 0.88) displayed maximal potential to metabolize the fungicide (86% and 80%, respectively) while forming intermediate metabolites, including 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid ((S)-9-hydroxy-9-isopropyl-1,2,3,4-tetrahydro-1,4-methanonaphthalen-5-yl)-amide, 3-difluoromethyl-1H-pyrazole-4-carboxylic acid, and 3-difluoromethyl-1-methyl-1H-pyrazole-4-amide. Isopyrazam degradation by all strains, AT, PC, AFu, AN, AF, XA, and PS, was found to be 11%, 18%, 21%, 21%, 18%, 30%, 80%, and 86%, respectively, after 35 days, elucidating the effectiveness of all the utilized strains in degrading isopyrazam at varying rates. The descending order of half-lives (days) obtained is as follows: AT (56.8) > PC (44.7) > AFu (40.7) > AN (39.6) > AF (32.6) > XA (28.1) > PS (21) days. Current research can influence imperative and significant environment-friendly bioremedial strategies for xenobiotic eradication from the ecological compartments.
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Affiliation(s)
- Khuram Shahzad Ahmad
- Department of Environmental Sciences, Fatima Jinnah Women University, Rawalpindi, Pakistan
| | - Palwasha Gul
- Department of Environmental Sciences, Fatima Jinnah Women University, Rawalpindi, Pakistan
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24
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Chang P. Genome‐wide nucleotide variation distinguishesAspergillus flavusfromAspergillus oryzaeand helps to reveal origins of atoxigenicA. flavusbiocontrol strains. J Appl Microbiol 2019; 127:1511-1520. [DOI: 10.1111/jam.14419] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/13/2019] [Accepted: 08/15/2019] [Indexed: 11/30/2022]
Affiliation(s)
- P.‐K. Chang
- Southern Regional Research Center Agricultural Research Service U. S. Department of Agriculture New Orleans LA USA
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