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Tang Y, Liu X, Dong L, He S. Screening and identification of an aflatoxin B 1-degrading strain from the Qinghai-Tibet Plateau and biodegradation products analysis. Front Microbiol 2024; 15:1367297. [PMID: 38751722 PMCID: PMC11094616 DOI: 10.3389/fmicb.2024.1367297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 04/03/2024] [Indexed: 05/18/2024] Open
Abstract
This research aimed to address the issue of aflatoxin B1 (AFB1) contamination, which posed severe health and economic consequences. This study involved exploring unique species resources in the Qinghai-Tibet Plateau, screening strains capable of degrading AFB1. UPLC-Q-Orbitrap HRMS and NMR were employed to examine the degradation process and identify the structure of the degradation products. Results showed that Bacillus amyloliquefaciens YUAD7, isolated from yak dung in the Qinghai-Tibet Plateau, removed 91.7% of AFB1 from TSB-AFB1 medium with an AFB1 concentration of 10 μg/mL (72 h, 37°C, pH 6.8) and over 85% of AFB1 from real food samples at 10 μg/g (72 h, 37°C), exhibiting strong AFB1 degradation activity. Bacillus amyloliquefaciens YUAD7's extracellular secretions played a major role in AFB1 degradation mediated and could still degrade AFB1 by 43.16% after boiling for 20 min. Moreover, B. amyloliquefaciens YUAD7 demonstrated the capability to decompose AFB1 through processes such as hydrogenation, enzyme modification, and the elimination of the -CO group, resulting in the formation of smaller non-toxic molecules. Identified products include C12H14O4, C5H12N2O2, C10H14O2, C4H12N2O, with a structure consisting of dimethoxyphenyl and enoic acid, dimethyl-amino and ethyl carbamate, polyunsaturated fatty acid, and aminomethyl. The results indicated that B. amyloliquefaciens YUAD7 could be a potentially valuable strain for industrial-scale biodegradation of AFB1 and providing technical support and new perspectives for research on biodegradation products.
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Affiliation(s)
| | - Xiaojing Liu
- College of Pratacultural Science, Gan Su Agricultural University, Lanzhou, China
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Rasheed U, Cotty PJ, Ain QU, Wang Y, Liu B. Efficacy of atoxigenic Aspergillus flavus from southern China as biocontrol agents against aflatoxin contamination in corn and peanuts. Pestic Biochem Physiol 2024; 201:105887. [PMID: 38685218 DOI: 10.1016/j.pestbp.2024.105887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/23/2024] [Accepted: 03/24/2024] [Indexed: 05/02/2024]
Abstract
Aspergillus flavus is a ubiquitous facultative pathogen that routinely infects important crops leading to formation of aflatoxins during crop development and after harvest. Corn and peanuts in warm and/or drought-prone regions are highly susceptible to aflatoxin contamination. Controlling aflatoxin using atoxigenic A. flavus is a widely adopted strategy. However, no A. flavus genotypes are currently approved for use in China. The current study aimed to select atoxigenic A. flavus endemic to Guangxi Zhuang Autonomous Region with potential as active ingredients of aflatoxin biocontrol products. A total of 204 A. flavus isolates from corn, peanuts, and field soil were evaluated for ability to produce the targeted mycotoxins. Overall, 57.3% could not produce aflatoxins while 17.15% were incapable of producing both aflatoxins and CPA. Atoxigenic germplasm endemic to Guangxi was highly diverse, yielding 8 different gene deletion patterns in the aflatoxin and CPA biosynthesis gene clusters ranging from no deletion to deletion of both clusters. Inoculation of corn and peanuts with both an aflatoxin producer and selected atoxigenic genotypes showed significant reduction (74 to 99%) in aflatoxin B1 (AFB1) formation compared with inoculation with the aflatoxin producer alone. Atoxigenic genotypes also efficiently degraded AFB1 (61%). Furthermore, atoxigenic isolates were also highly efficient at reducing aflatoxin concentrations even when present at lower concentrations than aflatoxin producers. The use of multiple atoxigenics was not always as effective as the use of a single atoxigenic. Effective atoxigenic genotypes of A. flavus with known mechanisms of atoxigenicity are demonstrated to be endemic to Southern China. These A. flavus may be utilized as active ingredients of biocontrol products without concern for detrimental impacts that may result from introduction of exotic fungi. Field efficacy trials in the agroecosystems of Southern China are needed to determine the extent to which such products may allow the production of safer food and feed.
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Affiliation(s)
- Usman Rasheed
- Institute of Applied Microbiology, College of Agriculture, Guangxi University, Guangxi Key Laboratory for Agro-Environment and Agro-Product Safety, Nanning 530004, China
| | - Peter J Cotty
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Qurat Ul Ain
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning, China
| | - YiFan Wang
- Institute of Applied Microbiology, College of Agriculture, Guangxi University, Guangxi Key Laboratory for Agro-Environment and Agro-Product Safety, Nanning 530004, China
| | - Bin Liu
- Institute of Applied Microbiology, College of Agriculture, Guangxi University, Guangxi Key Laboratory for Agro-Environment and Agro-Product Safety, Nanning 530004, China.
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Katati B, Kovács S, Njapau H, Kachapulula PW, Zwaan BJ, van Diepeningen AD, Schoustra SE. Maize Aspergillus section Flavi isolate diversity may be distinct from that of soil and subsequently the source of aflatoxin contamination. Mycotoxin Res 2024:10.1007/s12550-024-00532-7. [PMID: 38647834 DOI: 10.1007/s12550-024-00532-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 03/17/2024] [Accepted: 03/20/2024] [Indexed: 04/25/2024]
Abstract
Aspergillus section Flavi (Flavi) is a diverse group of fungal species whose common members include A. flavus and A. parasiticus. These are well-known for the production of aflatoxin (AF) B and G and other toxic metabolites, like cyclopiazonic acid (CPA). They are saprophytic soil dwellers and also become crop opportunistic epiphytes. The consequence is contamination of the crop with mycotoxins, such as carcinogenic AF. We investigated the Flavi community structure of maize and that of their surrounding soil, including their mycotoxigenicity. Furthermore, we investigated the link of the maize Flavi diversity with preharvest maize AF levels. The study was carried out in four selected districts of Zambia, in a low rainfall zone. The Flavi characterisation was triphasic, involving morphological (colony colour and sclerotia formation), metabolic (AF and CPA production) and genetic (calmodulin gene polymorphism) analyses. Flavi abundance was determined by dilution plate technique on modified rose Bengal agar. Results showed that Flavi communities on maize and in soil differed. Maize had a higher Flavi species diversity than soil. A. parasiticus dominated the soil community by frequency of field appearance (85%), while maize was dominated by A. minisclerotigenes (45%). CPA-producers with or without AF production dominated the maize (65%) while producers of only AF (B/G) dominated the soil (88%). The ratio between maize A. parasiticus and A. minisclerotigenes abundance seemed to have had a bearing on the levels of AF in maize, with a ratio close to 1:1 having higher levels than a pure community of either A. parasiticus or A. minisclerotigenes.
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Affiliation(s)
- Bwalya Katati
- Laboratory of Genetics, Wageningen University and Research, Wageningen, The Netherlands.
- Mycotoxicology Laboratory, National Institute for Scientific and Industrial Research, Lusaka, Zambia.
| | - Stan Kovács
- Laboratory of Genetics, Wageningen University and Research, Wageningen, The Netherlands
| | - Henry Njapau
- Mycotoxicology Laboratory, National Institute for Scientific and Industrial Research, Lusaka, Zambia
| | | | - Bas J Zwaan
- Laboratory of Genetics, Wageningen University and Research, Wageningen, The Netherlands
| | - Anne D van Diepeningen
- Biointeractions and Plant Health, Wageningen University and Research, Wageningen, The Netherlands
| | - Sijmen E Schoustra
- Laboratory of Genetics, Wageningen University and Research, Wageningen, The Netherlands
- School of Agricultural Sciences, University of Zambia, Lusaka, Zambia
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Song Y, Liu X, Feng S, Zhao K, Qi Z, Wu W, Xiao J, Xu H, Ran M, Qin B. Discovery, Identification, and Insecticidal Activity of an Aspergillus flavus Strain Isolated from a Saline-Alkali Soil Sample. Microorganisms 2023; 11:2788. [PMID: 38004799 PMCID: PMC10673062 DOI: 10.3390/microorganisms11112788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/04/2023] [Accepted: 11/14/2023] [Indexed: 11/26/2023] Open
Abstract
Aphids are one of the most destructive pests in agricultural production. In addition, aphids are able to easily develop resistance to chemical insecticides due to their rapid reproduction and short generation periods. To explore an effective and environmentally friendly aphid control strategy, we isolated and examined a fungus with aphid-parasitizing activity. The strain (YJNfs21.11) was identified as Aspergillus flavus by ITS, 28S, and BenA gene sequence analysis. Scanning electron microscopy and transmission electron microscopy revealed that the infection hyphae of 'YJNfs21.11' colonized and penetrated the aphid epidermal layer and subsequently colonized the body cavity. Field experiments showed that 'YJNfs21.11' and its fermentation products exerted considerable control on aphids, with a corrected efficacy of 96.87%. The lipase, protease, and chitinase secreted by fungi help aphid cuticle degradation, thus assisting spores in completing the infection process. Additionally, changes were observed in the mobility and physical signs of aphids, with death occurring within 60 h of infection. Our results demonstrate that A. flavus 'YJNfs21.11' exhibits considerable control on Aphis gossypii Glover and Hyalopterus arundimis Fabricius, making it a suitable biological control agent.
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Affiliation(s)
- Yuxin Song
- College of Life Sciences, Northwest A&F University, Xianyang 712100, China; (Y.S.); (X.L.); (S.F.); (K.Z.); (J.X.); (H.X.); (M.R.)
| | - Xiaoli Liu
- College of Life Sciences, Northwest A&F University, Xianyang 712100, China; (Y.S.); (X.L.); (S.F.); (K.Z.); (J.X.); (H.X.); (M.R.)
| | - Shirong Feng
- College of Life Sciences, Northwest A&F University, Xianyang 712100, China; (Y.S.); (X.L.); (S.F.); (K.Z.); (J.X.); (H.X.); (M.R.)
| | - Kangbo Zhao
- College of Life Sciences, Northwest A&F University, Xianyang 712100, China; (Y.S.); (X.L.); (S.F.); (K.Z.); (J.X.); (H.X.); (M.R.)
| | - Zhijun Qi
- College of Plant Protection, Northwest A&F University, Xianyang 712100, China; (Z.Q.); (W.W.)
| | - Wenjun Wu
- College of Plant Protection, Northwest A&F University, Xianyang 712100, China; (Z.Q.); (W.W.)
- Institute of Pesticides, Northwest A&F University, Xianyang 712100, China
| | - Jie Xiao
- College of Life Sciences, Northwest A&F University, Xianyang 712100, China; (Y.S.); (X.L.); (S.F.); (K.Z.); (J.X.); (H.X.); (M.R.)
| | - Hong Xu
- College of Life Sciences, Northwest A&F University, Xianyang 712100, China; (Y.S.); (X.L.); (S.F.); (K.Z.); (J.X.); (H.X.); (M.R.)
| | - Mingwei Ran
- College of Life Sciences, Northwest A&F University, Xianyang 712100, China; (Y.S.); (X.L.); (S.F.); (K.Z.); (J.X.); (H.X.); (M.R.)
| | - Baofu Qin
- College of Life Sciences, Northwest A&F University, Xianyang 712100, China; (Y.S.); (X.L.); (S.F.); (K.Z.); (J.X.); (H.X.); (M.R.)
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Hernández-Martínez SP, Delgado-Cedeño A, Ramos-Zayas Y, Franco-Molina MA, Méndez-Zamora G, Marroquín-Cardona AG, Kawas JR. Aluminosilicates as a Double-Edged Sword: Adsorption of Aflatoxin B 1 and Sequestration of Essential Trace Minerals in an In Vitro Gastrointestinal Poultry Model. Toxins (Basel) 2023; 15:519. [PMID: 37755945 PMCID: PMC10534799 DOI: 10.3390/toxins15090519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/27/2023] [Accepted: 08/05/2023] [Indexed: 09/28/2023] Open
Abstract
Aflatoxins can cause intoxication and poisoning in animals and humans. Among these molecules, aflatoxin B1 (AFB1) is the most dangerous because of its carcinogenic and mutagenic properties. To mitigate these effects, clay adsorbents are commonly included in the diet of animals to adsorb the carcinogens and prevent their absorption in the gastrointestinal tract. In this study, four clays, three smectites (C-1, C-2, and C-3), and one zeolite (C-4), were compared as adsorbents of AFB1 and trace inorganic nutrients using an in vitro gastrointestinal model for poultry. Characterization of the clays using Fourier transform infrared spectroscopy revealed characteristic bands of smectites in C-1, C-2, and C-3 (stretching vibrations of Si-O, Al-O-Si, and Si-O-Si). The C-4 presented bands related to the bending vibration of structural units (Si-O-Si and Al-O-Si). X-ray diffraction analysis showed that C-1 is a montmorillonite, C-2 is a beidellite, C-3 is a beidellite-Ca-montmorillonite, and C-4 is a clinoptilolite. The elemental compositions of the clays showed alumina, silica, iron, calcium, and sodium contents. The cation exchange capacity was higher in C-3 clay (60.2 cmol(+)/kg) in contrast with the other clays. The AFB1 adsorption of C-1 was the highest (98%; p ˂ 0.001), followed by C-2 (94%). However, all the clays also sequestered trace inorganic nutrients (Fe, Mn, Zn, and Se). Both smectites, montmorillonite and beidellite, were the most suitable for use as adsorbents of AFB1.
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Affiliation(s)
- Sara Paola Hernández-Martínez
- Facultad de Agronomía, Universidad Autónoma de Nuevo León, Escobedo 66050, Nuevo León, Mexico; (S.P.H.-M.); (G.M.-Z.)
- MNA de México, Juárez 67250, Nuevo León, Mexico; (A.D.-C.); (Y.R.-Z.)
| | | | - Yareellys Ramos-Zayas
- MNA de México, Juárez 67250, Nuevo León, Mexico; (A.D.-C.); (Y.R.-Z.)
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Nuevo León, Escobedo 66050, Nuevo León, Mexico
| | | | - Gerardo Méndez-Zamora
- Facultad de Agronomía, Universidad Autónoma de Nuevo León, Escobedo 66050, Nuevo León, Mexico; (S.P.H.-M.); (G.M.-Z.)
| | | | - Jorge R. Kawas
- Facultad de Agronomía, Universidad Autónoma de Nuevo León, Escobedo 66050, Nuevo León, Mexico; (S.P.H.-M.); (G.M.-Z.)
- MNA de México, Juárez 67250, Nuevo León, Mexico; (A.D.-C.); (Y.R.-Z.)
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Katati B, Kovacs S, Njapau H, Kachapulula PW, Zwaan BJ, van Diepeningen AD, Schoustra SE. Aflatoxigenic Aspergillus Modulates Aflatoxin-B1 Levels through an Antioxidative Mechanism. J Fungi (Basel) 2023; 9:690. [PMID: 37367626 DOI: 10.3390/jof9060690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/10/2023] [Accepted: 06/12/2023] [Indexed: 06/28/2023] Open
Abstract
Aflatoxins (AFs) are considered to play important functions in species of Aspergillus section Flavi including an antioxidative role, as a deterrent against fungivorous insects, and in antibiosis. Atoxigenic Flavi are known to degrade AF-B1 (B1). To better understand the purpose of AF degradation, we investigated the degradation of B1 and AF-G1 (G1) in an antioxidative role in Flavi. Atoxigenic and toxigenic Flavi were treated with artificial B1 and G1 with or without the antioxidant selenium (Se), which is expected to affect levels of AF. After incubations, AF levels were measured by HPLC. To estimate which population would likely be favoured between toxigenic and atoxigenic Flavi under Se, we investigated the fitness, by spore count, of the Flavi as a result of exposure to 0, 0.40, and 0.86 µg/g Se in 3%-sucrose cornmeal agar (3gCMA). Results showed that levels B1 in medium without Se were reduced in all isolates, while G1 did not significantly change. When the medium was treated with Se, toxigenic Flavi significantly digested less B1, while levels of G1 significantly increased. Se did not affect the digestion of B1 in atoxigenic Flavi, and also did not alter levels of G1. Furthermore, atoxigenic strains were significantly fitter than toxigenic strains at Se 0.86 µg/g 3gCMA. Findings show that while atoxigenic Flavi degraded B1, toxigenic Flavi modulated its levels through an antioxidative mechanism to levels less than they produced. Furthermore, B1 was preferred in the antioxidative role compared to G1 in the toxigenic isolates. The higher fitness of atoxigenic over toxigenic counterparts at a plant non-lethal dose of 0.86 µg/g would be a useful attribute for integration in the broader biocontrol prospects of toxigenic Flavi.
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Affiliation(s)
- Bwalya Katati
- Laboratory of Genetics, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
- Mycotoxicology Laboratory, National Institute for Scientific and Industrial Research, Lusaka 310158, Zambia
| | - Stan Kovacs
- Laboratory of Genetics, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
| | - Henry Njapau
- Mycotoxicology Laboratory, National Institute for Scientific and Industrial Research, Lusaka 310158, Zambia
| | - Paul W Kachapulula
- School of Agricultural Sciences, University of Zambia, Lusaka 10101, Zambia
| | - Bas J Zwaan
- Laboratory of Genetics, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
| | - Anne D van Diepeningen
- Biointeractions and Plant Health, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
| | - Sijmen E Schoustra
- Laboratory of Genetics, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
- School of Agricultural Sciences, University of Zambia, Lusaka 10101, Zambia
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Castano-Duque L, Lebar MD, Carter-Wientjes C, Ambrogio D, Rajasekaran K. Flavonoids Modulate Aspergillus flavus Proliferation and Aflatoxin Production. J Fungi (Basel) 2022; 8:1211. [PMID: 36422032 PMCID: PMC9693025 DOI: 10.3390/jof8111211] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/02/2022] [Accepted: 11/10/2022] [Indexed: 08/26/2023] Open
Abstract
Aflatoxins are carcinogenic mycotoxins produced by Aspergillus flavus. They contaminate major food crops, particularly corn, and pose a worldwide health concern. Flavonoid production has been correlated to resistance to aflatoxin accumulation in corn. The effects of flavonoids on fungal proliferation and aflatoxin production are not well understood. In this study, we performed bioassays, fluorescence and scanning electron microscopy, and total antioxidant analysis to determine the effects of three flavonoids (apigenin, luteolin, and quercetin) on proliferation and aflatoxin production in A. flavus NRRL 3357. Results showed that concentrations of apigenin and luteolin modulated fungal proliferation and aflatoxin production in a dose-dependent manner, leading to inhibition or promotion of proliferation and toxin production. Microscopy studies of fungi exposed to flavonoids showed mycelial cell wall disruption, abnormal cell wall invaginations, and tears. Fluorescent enhancement of apigenin and luteolin using Naturstoff reagent A showed that these chemicals localized in sphere-like structures on the mycelia surface. Fungi exposed to low concentrations of apigenin, luteolin, and quercetin lowered the total antioxidant capacity in the environment compared to controls. Our results indicate that flavonoids disrupt cell wall integrity and may localize in vesicle-like structures. We hypothesize that flavonoids could act as potential signaling molecules at low concentrations and change the oxidative state of the microenvironment, either or both of which may lead to reduction of fungal proliferation and aflatoxin production.
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Affiliation(s)
- Lina Castano-Duque
- United States Department of Agriculture—Agriculture Research Services, New Orleans, LA 70124, USA
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Alaniz Zanon MS, Bossa M, Chiotta ML, Oddino C, Giovanini D, Cardoso ML, Bartosik RE, Chulze SN. Pre-harvest strategy for reducing aflatoxin accumulation during storage of maize in Argentina. Int J Food Microbiol 2022; 380:109887. [DOI: 10.1016/j.ijfoodmicro.2022.109887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 08/03/2022] [Accepted: 08/22/2022] [Indexed: 11/21/2022]
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Shen P, Jia Y, Shi S, Sun J, Han X. Analytical and biomedical applications of microfluidics in traditional Chinese medicine research. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Sweany RR, DeRobertis CD, Kaller MD, Damann KE. Intraspecific Growth and Aflatoxin Inhibition Responses to Atoxigenic Aspergillus flavus: Evidence of Secreted, Inhibitory Substances in Biocontrol. Phytopathology 2022; 112:2084-2098. [PMID: 35502929 DOI: 10.1094/phyto-01-21-0022-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The fungus Aspergillus flavus infects corn, peanut, and cottonseed, and contaminates seeds with acutely poisonous and carcinogenic aflatoxin. Aflatoxin contamination is a perennial threat in tropical and subtropical climates. Nonaflatoxin-producing isolates (atoxigenic) are deployed in fields to mitigate aflatoxin contamination. The biocontrol competitively excludes toxigenic A. flavus via direct replacement and thigmoregulated (touch) toxin inhibition mechanisms. To understand the broad-spectrum toxin inhibition, toxigenic isolates representing different mating types and sclerotia sizes were individually cocultured with different atoxigenic biocontrol isolates. To determine whether more inhibitory isolates had a competitive advantage to displace or touch inhibit toxigenic isolates, biomass accumulation rates were determined for each isolate. Finally, to determine whether atoxigenic isolates could inhibit aflatoxin production without touch, atoxigenic isolates were grown separated from a single toxigenic isolate by a membrane. Atoxigenic isolates 17, Af36, and K49 had superior abilities to inhibit toxin production. Small (<400 µm) sclerotial, Mat1-1 isolates were not as completely inhibited as others by most atoxigenic isolates. As expected for both direct replacement and touch inhibition, the fastest-growing atoxigenic isolates inhibited aflatoxin production the most, except for atoxigenic Af36 and K49. Aflatoxin production was inhibited when toxigenic and atoxigenic isolates were grown separately, especially by slow-growing atoxigenic Af36 and K49. Additionally, fungus-free filtrates from atoxigenic cultures inhibited aflatoxin production. Toxin production inhibition without direct contact revealed secretion of diffusible chemicals as an additional biocontrol mechanism. Biocontrol formulations should be improved by identifying isolates with broad-spectrum, high-inhibition capabilities and production of secreted inhibitory chemicals.
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Affiliation(s)
- Rebecca R Sweany
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803
| | - Catherine D DeRobertis
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803
| | - Michael D Kaller
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, LA 70803
| | - Kenneth E Damann
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803
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Singh P, Mehl HL, Orbach MJ, Callicott KA, Cotty PJ. Genetic Diversity of Aspergillus flavus Associated with Chili in Nigeria and Identification of Haplotypes with Potential in Aflatoxin Mitigation. Plant Dis 2022; 106:1818-1825. [PMID: 35084943 DOI: 10.1094/pdis-07-21-1464-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Dried red chili (Capsicum spp.), a widely produced and consumed spice in Nigeria, is often contaminated by aflatoxins. Aflatoxins are potent mycotoxins of severe health and economic concern worldwide. Aspergillus flavus often contaminates crops with aflatoxins in warm regions; however, not all isolates are aflatoxin producers. Nonaflatoxigenic isolates have potential as biocontrol agents for aflatoxin mitigation. The current study examined the genetic diversity of A. flavus (n = 325) associated with chilies in Nigeria and identified 123 nonaflatoxigenic isolates. The Nigerian A. flavus isolates from chili were diverse at 17 microsatellite loci, with 5 to 36 alleles per locus, and included 152 haplotypes. The isolates that are active ingredients in Aflasafe, registered for aflatoxin biocontrol on maize and groundnuts in Nigeria, did not share haplotypes with the chili isolates. Of the 152 haplotypes, 65% produced aflatoxins in autoclaved maize, some of which (17%) produced >100,000 µg/kg of aflatoxins. Aflatoxins were not detected in 35% of the haplotypes. Cluster amplification pattern assay detected large deletions in the aflatoxin biosynthetic clusters of some (32%) of the nonaflatoxigenic haplotypes. Coinfection of chili with nonaflatoxigenic isolates from chilies (n = 7) and A. aflatoxiformans resulted in a significantly greater average reduction in total aflatoxins compared with that achieved by Aflasafe active ingredient isolates (P < 0.01). These nonaflatoxigenic isolates are a genetic resource for the development of biological control products for aflatoxin mitigation in chilies in Nigeria and should be evaluated under field conditions.
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Affiliation(s)
- Pummi Singh
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, U.S.A
| | | | - Marc J Orbach
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, U.S.A
| | | | - Peter J Cotty
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, U.S.A
- USDA-ARS, Tucson, AZ 85701, U.S.A
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
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Rangel-Muñoz EJ, Valdivia-Flores AG, Hernández-Delgado S, Cruz-Vázquez C, de-Luna-López MC, Quezada-Tristán T, Ortiz-Martínez R, Mayek-Pérez N. Assessment of the Potential of a Native Non-Aflatoxigenic Aspergillus flavus Isolate to Reduce Aflatoxin Contamination in Dairy Feed. Toxins (Basel) 2022; 14. [PMID: 35878175 DOI: 10.3390/toxins14070437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/16/2022] [Accepted: 06/25/2022] [Indexed: 12/03/2022] Open
Abstract
Aspergillus species can produce aflatoxins (AFs), which can severely affect human and animal health. The objective was to evaluate the efficacy of reducing AF contamination of a non-aflatoxigenic isolate of A. flavus experimentally coinoculated with different aflatoxigenic strains in whole plant (WP), corn silage (CS), immature grains (IG) and in culture media (CM). An L-morphotype of A. flavus (CS1) was obtained from CS in a dairy farm located in the Mexican Highland Plateau; The CS1 failed to amplify the AFs biosynthetic pathway regulatory gene (aflR). Monosporic CS1 isolates were coinoculated in WP, CS, IG and CM, together with A. flavus strains with known aflatoxigenic capacity (originating from Cuautitlán and Tamaulipas, Mexico), and native isolates from concentrate feed (CF1, CF2 and CF3) and CS (CS2, CS3). AF production was evaluated by HPLC and fungal growth rate was measured on culture media. The positive control strains and those isolated from CF produced a large average amount of AFs (15,622 ± 3952 and 12,189 ± 3311 µg/kg), whereas A. flavus strains obtained from CS produced a lower AF concentration (126 ± 25.9 µg/kg). CS1 was efficient (p < 0.01) in decreasing AF concentrations when coinoculated together with CF, CS and aflatoxigenic positive control strains (71.6−88.7, 51.0−51.1 and 63.1−71.5%) on WP, CS, IG and CM substrates (73.9−78.2, 65.1−73.7, 63.8−68.4 and 57.4−67.6%). The results suggest that the non-aflatoxigenic isolate can be an effective tool to reduce AF contamination in feed and to minimize the presence of its metabolites in raw milk and dairy products intended for human nutrition.
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13
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Zhu GY, Wang X, Chen TM, Wang SY, Chen X, Song ZW, Shi XC, Laborda P. First Report of Aspergillus flavus Causing Fruit Rot on Kiwifruit in China. Plant Dis 2022; 106:PDIS08211771PDN. [PMID: 34879727 DOI: 10.1094/pdis-08-21-1771-pdn] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Affiliation(s)
- G-Y Zhu
- School of Life Sciences, Nantong University, Nantong 226019, People's Republic of China
| | - X Wang
- School of Life Sciences, Nantong University, Nantong 226019, People's Republic of China
| | - T-M Chen
- School of Life Sciences, Nantong University, Nantong 226019, People's Republic of China
| | - S-Y Wang
- School of Life Sciences, Nantong University, Nantong 226019, People's Republic of China
| | - X Chen
- School of Life Sciences, Nantong University, Nantong 226019, People's Republic of China
| | - Z-W Song
- Eco-Environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201403, People's Republic of China
| | - X-C Shi
- School of Life Sciences, Nantong University, Nantong 226019, People's Republic of China
| | - P Laborda
- School of Life Sciences, Nantong University, Nantong 226019, People's Republic of China
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14
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Kumar V, Bahuguna A, Ramalingam S, Lee JS, Han SS, Chun HS, Kim M. Aflatoxin Reduction and Retardation of Aflatoxin Production by Microorganisms in Doenjang during a One-Year Fermentation. J Fungi (Basel) 2022; 8:jof8020190. [PMID: 35205943 PMCID: PMC8879751 DOI: 10.3390/jof8020190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/03/2022] [Accepted: 02/11/2022] [Indexed: 11/16/2022] Open
Abstract
Meju, a raw material for doenjang preparation, is highly vulnerable to aflatoxin-producing fungi. The aim of this study was to evaluate the effect of a one-year fermentation on aflatoxins and aflatoxin-producing fungi in doenjang spiked with aflatoxins B1, G1, B2, and G2 and inoculated with toxigenic Aspergillus flavus. A significant reduction in aflatoxins was observed after a year of fermentation, measuring 92.58%, 100%, 98.69%, and 100% of B1, G1, B2, and G2, respectively. After a year of fermentation, 6.95 ± 3.64 µg/kg of total aflatoxin was detected, which represents a 97.88% reduction in the total aflatoxin compared with the initial value (328.83 ± 36.60 µg/kg). Several aflatoxin-degrading fungi (Aspergillus versicolor, Cladosporium subcinereum, Aspergillus ochraceus) and bacteria (Bacillus albus, Bacillus velezensis) isolated from doenjang were identified as the major contributors to the reduction of aflatoxin. Furthermore, it was observed that most of the aflatoxin contamination in doenjang occurred during the meju stage, and this stage was found to be most susceptible to A. flavus contamination and growth. These findings reveal that native microorganisms mediate aflatoxin clean-up in doenjang during fermentation and support the use of such microorganisms as a starter culture for the preparation of aflatoxin-free doenjang.
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Affiliation(s)
- Vishal Kumar
- Department of Food Science and Technology, Yeungnam University, Gyeongsan 38541, Gyeongsangbuk-do, Korea; (V.K.); (A.B.); (S.R.)
| | - Ashutosh Bahuguna
- Department of Food Science and Technology, Yeungnam University, Gyeongsan 38541, Gyeongsangbuk-do, Korea; (V.K.); (A.B.); (S.R.)
| | - Srinivasan Ramalingam
- Department of Food Science and Technology, Yeungnam University, Gyeongsan 38541, Gyeongsangbuk-do, Korea; (V.K.); (A.B.); (S.R.)
| | - Jong Suk Lee
- Division of Food & Nutrition and Cook, Taegu Science University, Daegu 41453, Gyeongsangbuk-do, Korea;
| | - Sung Soo Han
- School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Gyeongsangbuk-do, Korea;
- Institute of Cell Culture, Yeungnam University, Gyeongsan 38541, Gyeongsangbuk-do, Korea
| | - Hyang Sook Chun
- School of Food Science and Technology, Chung-Ang University, Anseong 17546, Gyeonggi-do, Korea;
| | - Myunghee Kim
- Department of Food Science and Technology, Yeungnam University, Gyeongsan 38541, Gyeongsangbuk-do, Korea; (V.K.); (A.B.); (S.R.)
- Institute of Cell Culture, Yeungnam University, Gyeongsan 38541, Gyeongsangbuk-do, Korea
- Correspondence: ; Tel.: +82-53-810-2958
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15
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Moral J, Garcia-Lopez MT, Gordon A, Ortega-Beltran A, Puckett R, Tomari K, Gradziel TM, Michailides TJ. Resistance to Aspergillus flavus and Aspergillus parasiticus in Almond Advanced Selections and Cultivars and Its Interaction with the Aflatoxin Biocontrol Strategy. Plant Dis 2022; 106:504-509. [PMID: 34569835 DOI: 10.1094/pdis-05-21-0892-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Aflatoxin contamination of almond kernels, caused by Aspergillus flavus and A. parasiticus, is a severe concern for growers because of its high toxicity. In California, the global leader of almond production, aflatoxin can be managed by applying the biological control strain AF36 of A. flavus and selecting resistant cultivars. Here, we classified the almond genotypes by K-Means cluster analysis into three groups (susceptible [S], moderately susceptible [MS], or resistant [R]) based on aflatoxin content of inoculated kernels. The protective effects of the shell and seedcoat in preventing aflatoxin contamination were also examined. The presence of intact shells reduced aflatoxin contamination >100-fold. The seedcoat provided a layer of protection but not complete protection. In kernel inoculation assays, none of the studied almond genotypes showed a total resistance to the pathogen. However, nine traditional cultivars and four advanced selections were classified as R. Because these advanced selections contained germplasm derived from peach, we compared the kernel resistance of three peach cultivars to that shown by kernels of an R (Sonora) and an S (Carmel) almond cultivar and five pistachio cultivars. Overall, peach kernels were significantly more resistant to the pathogen than almond kernels, which were more resistant than pistachio kernels. Finally, we studied the combined effect of the cultivar resistance and the biocontrol strain AF36 in limiting aflatoxin contamination. For this, we coinoculated almond kernels of R Sonora and S Carmel with AF36 72 h before or 48 h after inoculating with an aflatoxin-producing strain of A. flavus. The percentage of aflatoxin reduction by AF36 strain was greater in kernels of Carmel (98%) than in those of Sonora (83%). Cultivar resistance also affected the kernel colonization by the biological control strain. AF36 strain limited aflatoxin contamination in almond kernels even when applied 48 h after the aflatoxin-producing strain. Our results show that biocontrol combined with the use of cultivars with resistance to aflatoxin contamination can result in a more robust protection strategy than the use of either practice in isolation.
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Affiliation(s)
- Juan Moral
- Department of Agronomy, Maria de Maeztu Excellence Unit, University of Córdoba, 14071 Córdoba, Spain
- Department of Biology, College of Science and Mathematics, California State University, Fresno, CA 93740, U.S.A
| | - M Teresa Garcia-Lopez
- Department of Agronomy, Maria de Maeztu Excellence Unit, University of Córdoba, 14071 Córdoba, Spain
- Department of Plant Pathology, University of California-Davis Kearney Agricultural Research and Extension Center, Parlier, CA 93648, U.S.A
| | - Ana Gordon
- Department of Agronomy, Maria de Maeztu Excellence Unit, University of Córdoba, 14071 Córdoba, Spain
| | | | - Ryan Puckett
- Department of Plant Pathology, University of California-Davis Kearney Agricultural Research and Extension Center, Parlier, CA 93648, U.S.A
| | - Kenji Tomari
- Department of Plant Pathology, University of California-Davis Kearney Agricultural Research and Extension Center, Parlier, CA 93648, U.S.A
| | - Thomas M Gradziel
- Department of Plant Sciences, University of California-Davis, Davis, CA 95616, U.S.A
| | - Themis J Michailides
- Department of Plant Pathology, University of California-Davis Kearney Agricultural Research and Extension Center, Parlier, CA 93648, U.S.A
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Sweany RR, Mack BM, Moore GG, Gilbert MK, Cary JW, Lebar MD, Rajasekaran K, Damann Jr. KE. Genetic Responses and Aflatoxin Inhibition during Co-Culture of Aflatoxigenic and Non-Aflatoxigenic Aspergillus flavus. Toxins (Basel) 2021; 13:794. [PMID: 34822579 PMCID: PMC8618995 DOI: 10.3390/toxins13110794] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/30/2021] [Accepted: 11/05/2021] [Indexed: 11/16/2022] Open
Abstract
Aflatoxin is a carcinogenic mycotoxin produced by Aspergillus flavus. Non-aflatoxigenic (Non-tox) A. flavus isolates are deployed in corn fields as biocontrol because they substantially reduce aflatoxin contamination via direct replacement and additionally via direct contact or touch with toxigenic (Tox) isolates and secretion of inhibitory/degradative chemicals. To understand touch inhibition, HPLC analysis and RNA sequencing examined aflatoxin production and gene expression of Non-tox isolate 17 and Tox isolate 53 mono-cultures and during their interaction in co-culture. Aflatoxin production was reduced by 99.7% in 72 h co-cultures. Fewer than expected unique reads were assigned to Tox 53 during co-culture, indicating its growth and/or gene expression was inhibited in response to Non-tox 17. Predicted secreted proteins and genes involved in oxidation/reduction were enriched in Non-tox 17 and co-cultures compared to Tox 53. Five secondary metabolite (SM) gene clusters and kojic acid synthesis genes were upregulated in Non-tox 17 compared to Tox 53 and a few were further upregulated in co-cultures in response to touch. These results suggest Non-tox strains can inhibit growth and aflatoxin gene cluster expression in Tox strains through touch. Additionally, upregulation of other SM genes and redox genes during the biocontrol interaction demonstrates a potential role of inhibitory SMs and antioxidants as additional biocontrol mechanisms and deserves further exploration to improve biocontrol formulations.
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Affiliation(s)
- Rebecca R. Sweany
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Brian M. Mack
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Geromy G. Moore
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Matthew K. Gilbert
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Jeffrey W. Cary
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Matthew D. Lebar
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Kanniah Rajasekaran
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Kenneth E. Damann Jr.
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
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