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Bush DS, Calla B, Berenbaum MR. An Aspergillus flavus strain from bee bread of the Western honey bee ( Apis mellifera) displays adaptations to distinctive features of the hive environment. Ecol Evol 2024; 14:e10918. [PMID: 38389995 PMCID: PMC10883247 DOI: 10.1002/ece3.10918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 12/20/2023] [Accepted: 01/08/2024] [Indexed: 02/24/2024] Open
Abstract
Aspergillus fungi are ubiquitous inhabitants of colonies of the western honey bee (Apis mellifera), where they interact with bees in associations ranging from parasitism to possible mutualism. Aspergillus Flavi fungi are frequently found in bee bread (pollen processed for longterm storage) and are thought to contribute to food preparation, processing, preservation, and digestion. Conditions in the hive are challenging for fungi due, in part, to xeric and acidic properties of bee bread and the omnipresence of propolis, an antimicrobial product manufactured by bees from plant resins. We used quantitative and qualitative assays to determine whether A. flavus isolated from bee bread demonstrates tolerance for hive environmental conditions in terms of temperature, pH, osmotic pressure, and propolis exposure. Comparisons made use of three strains of A. flavus: a fungal biocontrol product not known from beehives (AF36), a strain isolated from bee bread (AFBB) in hives from central Illinois, and a pathogenic strain from a honey bee colony displaying symptoms of stonebrood (AFPA). Strain AFBB displayed higher tolerance of acidic conditions, low matric potential (simulating xeric substrate), and propolis exposure than did other strains. A genomic comparison between this new strain and the reference NRRL-3357 showed that AFBB, like AF36, might be blocked from carrying out aflatoxin biosynthesis. Sequence comparisons also revealed several missense variants in genes that encode proteins regulating osmotolerance and osmotic pressure in Aspergillus spp., including SakA, SskB, GfdA, and TcsB/Sln1. Collectively, results of our laboratory assays and genetic analyses are consistent with the suggestion that the strain isolated from bee bread is adapted to the bee bread environment and may have persisted due to a coevolutionary relationship between Aspergillus and A. mellifera. This finding bolsters recent concerns about the effects of fungicide use near bee colonies and broadens the ecological importance of highly adaptable fungal strains.
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Affiliation(s)
- Daniel S Bush
- Deparment of Entomology University of Illinois Urbana Illinois USA
| | - Bernarda Calla
- USDA-ARS Pacific Shellfish Research Unit Corvallis Oregon USA
| | - May R Berenbaum
- Deparment of Entomology University of Illinois Urbana Illinois USA
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Tan S, Ma F, Wu Y, Xu Y, Niu A, Chen Y, Wang G, Qiu W. The biodiversity of Aspergillus flavus in stored rice grain leads to a decrease in the overall aflatoxin B 1 production in these species. Int J Food Microbiol 2023; 406:110416. [PMID: 37769398 DOI: 10.1016/j.ijfoodmicro.2023.110416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 09/11/2023] [Accepted: 09/22/2023] [Indexed: 09/30/2023]
Abstract
Aspergillus flavus is a significant fungus that poses a threat to food safety by producing mycotoxins in various crops. In this study, A. flavus isolates were obtained from storage rice collected from seven provinces in southern China, and their AFB1 production, biosynthesis genes presence, and diversity were detected. Results showed that 56 out of the 81 A. flavus isolates produced detectable levels of AFB1, and 71 isolates (87.6 %) possessed aflR gene in their AF synthesis gene cluster, while only 41 isolates (50.6 %) had the ver-1 gene present. Genetic diversity analysis using inter-simple sequence repeats (ISSR) markers revealed seven main clusters among the isolates and the genetic similarity coefficients of 81 A. flavus isolates ranged from 0.53 to 1.00. Additionally, coculture assays were conducted using two toxigenic and two atoxigenic isolates from the same grain depot to investigate the effect of intraspecific inhibition on AFB1 production and to assess the AFB1 contamination risk of storage rice. The in situ results demonstrated that the atoxigenic isolates effectively inhibited the AFB1 contamination of toxigenic isolates. These findings provide insight into the genetic diversity of A. flavus isolates populations and highlight the potential food safety hazards of them in stored rice grain in China.
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Affiliation(s)
- Song Tan
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Fang Ma
- Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Yajie Wu
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Yuancheng Xu
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Ajuan Niu
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Yuping Chen
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Guangyu Wang
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China.
| | - Weifen Qiu
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
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Ren Z, Chen R, Muhae-Ud-Din G, Fang M, Li T, Yang Y, Chen W, Gao L. Development of real-time PCR and droplet digital PCR based marker for the detection of Tilletia caries inciting common bunt of wheat. FRONTIERS IN PLANT SCIENCE 2022; 13:1031611. [PMID: 36507438 PMCID: PMC9732894 DOI: 10.3389/fpls.2022.1031611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 10/18/2022] [Indexed: 06/17/2023]
Abstract
This is the first study reporting droplet digital PCR and quantitative real time PCR for detection of Tilletia caries (syn. T. tritici), which causes common bunt of wheat and leads to yield losses of 80% in many wheat growing areas worldwide. To establish an accurate, rapid and quantifiable detection method, we tested 100 inter simple sequence repeats (ISSR) primers and obtained a species-specific fragment (515 bp) generated by ISSR 827. Then, a specific 266 bp band for the sequence characterized amplified region (SCAR) marker was produced from T. caries. The detection limit reached 50 pg/μL. Based on the SCAR marker, we further developed a higher sensitivity of quantitative real time-polymerase chain reaction (qRT-PCR) with a detection limit of 2.4 fg/μL, and droplet digital PCR (ddPCR) with a detection limit of 0.24 fg/μL. Both methods greatly improved the detection sensitivity of T. caries, which will be contribute a lot for quickly and accurately detection of T. caries, which causes wheat common bunt.
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Affiliation(s)
- Zhaoyu Ren
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Rongzhen Chen
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Department of Plant Protection, Shenyang Agricultural University, Liaoning, China
| | - Ghulam Muhae-Ud-Din
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Mingke Fang
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- College of Life Sciences, Yangtze University, Jingzhou, China
| | - Tianya Li
- Department of Plant Protection, Shenyang Agricultural University, Liaoning, China
| | - Yazheng Yang
- College of Life Sciences, Yangtze University, Jingzhou, China
| | - Wanquan Chen
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Li Gao
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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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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