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Bass E, Mutyambai DM, Midega CAO, Khan ZR, Kessler A. Associational Effects of Desmodium Intercropping on Maize Resistance and Secondary Metabolism. J Chem Ecol 2024; 50:299-318. [PMID: 38305931 DOI: 10.1007/s10886-024-01470-5] [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: 11/20/2023] [Revised: 01/11/2024] [Accepted: 01/13/2024] [Indexed: 02/03/2024]
Abstract
Intercropping is drawing increasing attention as a strategy to increase crop yields and manage pest pressure, however the mechanisms of associational resistance in diversified cropping systems remain controversial. We conducted a controlled experiment to assess the impact of co-planting with silverleaf Desmodium (Desmodium uncinatum) on maize secondary metabolism and resistance to herbivory by the spotted stemborer (Chilo partellus). Maize plants were grown either in the same pot with a Desmodium plant or adjacent to it in a separate pot. Our findings indicate that co-planting with Desmodium influences maize secondary metabolism and herbivore resistance through both above and below-ground mechanisms. Maize growing in the same pot with a Desmodium neighbor was less attractive for oviposition by spotted stemborer adults. However, maize exposed only to above-ground Desmodium cues generally showed increased susceptibility to spotted stemborer herbivory (through both increased oviposition and larval consumption). VOC emissions and tissue secondary metabolite titers were also altered in maize plants exposed to Desmodium cues, with stronger effects being observed when maize and Desmodium shared the same pot. Specifically, benzoxazinoids were strongly suppressed in maize roots by direct contact with a Desmodium neighbor while headspace emissions of short-chain aldehydes and alkylbenzenes were increased. These results imply that direct root contact or soil-borne cues play an important role in mediating associational effects on plant resistance in this system.
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Affiliation(s)
- Ethan Bass
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | - Daniel M Mutyambai
- International Centre of Insect Physiology and Ecology (Icipe), Nairobi, Kenya
- Department of Life Sciences, South Eastern Kenya University, P.O Box 170-90200, Kitui, Kenya
| | - Charles A O Midega
- Poverty and Health Integrated Solutions (PHIS), Kisumu, Kenya
- Unit for Environmental Sciences and Management, IPM Program, North-West University, Potchefstroom, South Africa
| | - Zeyaur R Khan
- International Centre of Insect Physiology and Ecology (Icipe), Nairobi, Kenya
- International Centre of Insect Physiology and Ecology, Mbita, Kenya
| | - André Kessler
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA.
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Impact of Volatile Organic Compounds on the Growth of Aspergillus flavus and Related Aflatoxin B1 Production: A Review. Int J Mol Sci 2022; 23:ijms232415557. [PMID: 36555197 PMCID: PMC9779742 DOI: 10.3390/ijms232415557] [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: 10/26/2022] [Revised: 11/30/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022] Open
Abstract
Volatile organic compounds (VOCs) are secondary metabolites of varied chemical nature that are emitted by living beings and participate in their interactions. In addition, some VOCs called bioactive VOCs cause changes in the metabolism of other living species that share the same environment. In recent years, knowledge on VOCs emitted by Aspergillus flavus, the main species producing aflatoxin B1 (AFB1), a highly harmful mycotoxin, has increased. This review presents an overview of all VOCs identified as a result of A. flavus toxigenic (AFB1-producing) and non-toxigenic (non AFB1-producing) strains growth on different substrates, and the factors influencing their emissions. We also included all bioactive VOCs, mixes of VOCs or volatolomes of microbial species that impact A. flavus growth and/or related AFB1 production. The modes of action of VOCs impacting the fungus development are presented. Finally, the potential applications of VOCs as biocontrol agents in the context of mycotoxin control are discussed.
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Ahmad MM, Qamar F, Saifi M, Abdin MZ. Natural inhibitors: A sustainable way to combat aflatoxins. Front Microbiol 2022; 13:993834. [PMID: 36569081 PMCID: PMC9773886 DOI: 10.3389/fmicb.2022.993834] [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: 07/14/2022] [Accepted: 10/31/2022] [Indexed: 12/13/2022] Open
Abstract
Among a few hundred mycotoxins, aflatoxins had always posed a major threat to the world. Apart from A. flavus, A. parasiticus, and A. nomius of Aspergillus genus, which are most toxin-producing strains, several fungal bodies including Fusarium, Penicillium, and Alternaria that can biosynthesis aflatoxins. Basically, there are four different types of aflatoxins (Aflatoxin B1 (AFB1), Aflatoxin B2 (AFB2), Aflatoxin G1 (AFG1), Aflatoxin G2 (AFG2)) are produced as secondary metabolites. There are certainly other types of aflatoxins found but they are the by-products of these toxins. The fungal agents generally infect the food crops during harvesting, storing, and/or transporting; making a heavy post-harvest as well as economic loss in both developed and developing countries. And while ingesting the crop products, these toxins get into the dietary system causing aflatoxicosis, liver cirrhosis, etc. Therefore, it is imperative to search for certain ways to control the spread of infections and/or production of these toxins which may also not harm the crop harvest. In this review, we are going to discuss some sustainable methods that can effectively control the spread of infection and inhibit the biosynthesis of aflatoxins.
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Affiliation(s)
- Malik M. Ahmad
- Department of Agriculture, Integral Institute of Agricultural Science and Technology (IIAST), Integral University, Lucknow, India
| | - Firdaus Qamar
- CTPD, Department of Biotechnology, School of Chemical and Life Sciences, New Delhi, India
| | - Monica Saifi
- CTPD, Department of Biotechnology, School of Chemical and Life Sciences, New Delhi, India
| | - Malik Zainul Abdin
- CTPD, Department of Biotechnology, School of Chemical and Life Sciences, New Delhi, India,*Correspondence: Malik Zainul Abdin,
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Chowdhury NN, Islam MN, Jafrin R, Rauf A, Khalil AA, Emran TB, Aljohani ASM, Alhumaydhi FA, Lorenzo JM, Shariati MA, Simal-Gandara J. Natural plant products as effective alternatives to synthetic chemicals for postharvest fruit storage management. Crit Rev Food Sci Nutr 2022; 63:10332-10350. [PMID: 35612470 DOI: 10.1080/10408398.2022.2079112] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Fruits contain enormous source of vitamins that provides energy to the human body. These are also affluent in essential and vital vitamins, minerals, fiber, and health-promoting components, which has led to an increase in fruit consumption in recent years. Though fruit consumption has expanded considerably in recent years, the use of synthetic chemicals to ripen or store fruits has been steadily increasing, resulting in postharvest deterioration. Alternatives to synthetic chemicals should be considered to control this problem. Instead of utilizing synthetic chemicals, this study suggests using natural plant products to control postharvest decay. The aim of this study indicates how natural plant products can be useful and effective to eliminate postharvest diseases rather than using synthetic chemicals. Several electronic databases were investigated as information sources, including Google Scholar, PubMed, Web of Science, Scopus, ScienceDirect, SpringerLink, Semantic Scholar, MEDLINE, and CNKI Scholar. The current review focused on the postharvest of fruits has become more and more necessary because of these vast demands of fruits. Pathogen-induced diseases are the main component and so the vast portion of fruits get wasted after harvest. Besides, it may occur harmful during harvesting and subsequent handling, storage, and marketing and after consumer purchasing and also causes for numerous endogenous and exogenous diseases via activating ROS, oxidative stress, lipid peroxidation, etc. However, pathogenicity can be halted by using postharvest originating natural fruits containing bioactive elements that may be responsible for the management of nutritional deficiency, inflammation, cancer, and so on. However, issues arising during the postharvest diseases must be controlled and resolved before releasing the horticultural commodities for commercialization. Therefore, the control of postharvest pathogens still depends on the use of synthetic fungicides; however, due to the problem of the development of the fungicide-resistant strains there is a good demand of public to eradicate the use of pesticides with the arrival of numerous diseases that are expanded in their intensity by the specific chemical product. By using of the organic or natural products for controlling postharvest diseases of fruits has become a mandatory step to take. In addition, antimicrobial packaging may have a greater impact on long-term food security by lowering the risk of pathogenicity and increasing the longevity of fruit shelf life. Taken together, natural chemicals as acetaldehyde, hexanal, eugenol, linalool, jasmonates, glucosinolates, essential oils, and many plant bioactive are reported for combating of the postharvest illnesses and guide to way of storage of fruits in this review.
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Affiliation(s)
- Nahidun Nesa Chowdhury
- Department of Pharmacy, International Islamic University Chittagong, Chittagong, Bangladesh
| | - Mohammad Nazmul Islam
- Department of Pharmacy, International Islamic University Chittagong, Chittagong, Bangladesh
| | - Rifat Jafrin
- Department of Pharmacy, International Islamic University Chittagong, Chittagong, Bangladesh
| | - Abdur Rauf
- Department of Chemistry, University of Swabi, Anbar, Khyber Pakhtunkhwa, Pakistan
| | - Anees Ahmed Khalil
- University Institute of Diet and Nutritional Sciences, Faculty of Allied Health Sciences, The University of Lahore, Pakistan
| | - Talha Bin Emran
- Department of Pharmacy, BGC Trust University Bangladesh, Chittagong, Bangladesh
| | - Abdullah S M Aljohani
- Department of Veterinary Medicine, College of Agriculture and Veterinary Medicine, Qassim University, Buraydah, Saudi Arabia
| | - Fahad A Alhumaydhi
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia
| | - Jose M Lorenzo
- Centro Tecnológico de la Carne de Galicia, Ourense, Spain
- Área de Tecnología de los Alimentos, Facultad de Ciencias de Ourense, Universidad de Vigo, Ourense, Spain
| | - Mohammad Ali Shariati
- K.G. Razumovsky Moscow State University of Technologies and Management, The First Cossack University), Moscow, Russia
| | - Jesus Simal-Gandara
- Universidade de Vigo, Nutrition and Bromatology Group, Analytical Chemistry and Food Science Department, Faculty of Science, Ourense, Spain
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5
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Pennerman KK, Yin G, Bennett JW. Eight-carbon volatiles: prominent fungal and plant interaction compounds. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:487-497. [PMID: 34727164 DOI: 10.1093/jxb/erab438] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 09/24/2021] [Indexed: 06/13/2023]
Abstract
Signaling via volatile organic compounds (VOCs) has historically been studied mostly by entomologists; however, botanists and mycologists are increasingly aware of the physiological potential of chemical communication in the gas phase. Most research to date focuses on the observed effects of VOCs on different organisms such as differential growth or metabolite production. However, with the increased interest in volatile signaling, more researchers are investigating the molecular mechanisms for these effects. Eight-carbon VOCs are among the most prevalent and best-studied fungal volatiles. Therefore, this review emphasizes examples of eight-carbon VOCs affecting plants and fungi. These compounds display different effects that include growth suppression in both plants and fungi, induction of defensive behaviors such as accumulation of mycotoxins, phytohormone signaling cascades, and the inhibition of spore and seed germination. Application of '-omics' and other next-generation sequencing techniques is poised to decipher the mechanistic basis of volatiles in plant-fungal communication.
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Affiliation(s)
- Kayla K Pennerman
- Joint Institute for Food Safety and Applied Nutrition, University of Maryland, College Park, MD 20742, USA
- United States Department of Agriculture, Toxicology and Mycotoxin Research Unit, Athens, GA 30605, USA
| | - Guohua Yin
- United States Department of Agriculture, Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Peoria, IL 61604, USA
- Department of Plant Biology, Rutgers University, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Joan W Bennett
- Department of Plant Biology, Rutgers University, The State University of New Jersey, New Brunswick, NJ 08901, USA
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6
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Zhao Q, Qiu Y, Wang X, Gu Y, Zhao Y, Wang Y, Yue T, Yuan Y. Inhibitory Effects of Eurotium cristatum on Growth and Aflatoxin B 1 Biosynthesis in Aspergillus flavus. Front Microbiol 2020; 11:921. [PMID: 32477315 PMCID: PMC7242626 DOI: 10.3389/fmicb.2020.00921] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 04/17/2020] [Indexed: 12/20/2022] Open
Abstract
Probiotic strain Eurotium cristatum was isolated from Chinese Fuzhuan brick-tea and tested for its in vitro activity against aflatoxigenic Aspergillus flavus. Results indicated that E. cristatum can inhibit the radial growth of A. flavus. Furthermore, this inhibition might be caused by E. cristatum secondary metabolites. The ability of culture filtrate of strain E. cristatum against growth and aflatoxin B1 production by toxigenic A. flavus was evaluated in vitro. Meanwhile, the influence of filtrate on spore morphology of A. flavus was analyzed by scanning electron microscopy (SEM). Results demonstrated that both radial growth of A. flavus and aflatoxin B1 production were significantly weakened following increases in the E. cristatum culture filtrate concentration. In addition, SEM showed that the culture filtrate seriously damaged hyphae morphology. Gas chromatography mass spectrometry (GC/MS) analysis of the E. cristatum culture supernatant revealed the presence of multiple antifungal compounds. Real-time quantitative polymerase chain reaction (RT-qPCR) analysis showed that the expression of aflatoxin biosynthesis-related genes (aflD, aflQ, and aflS) were down-regulated. Importantly, this latter occurrence resulted in a reduction of the AflS/AflR ratio. Interestingly, cell-free supernatants of E. cristatum facilitated the effective degradation of aflatoxin B1. In addition, two degradation products of aflatoxin B1 lacking the toxic and carcinogenic lactone ring were identified. A toxicity study on the HepG2 cells showed that the degradation compounds were less toxic when compared with AFB1.
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Affiliation(s)
- Qiannan Zhao
- College of Food Science and Engineering, Northwest A&F University, Yangling, China.,Laboratory of Quality & Safety Risk Assessment for Agro-products, Ministry of Agriculture, Yangling, China
| | - Yue Qiu
- College of Food Science and Engineering, Northwest A&F University, Yangling, China.,Laboratory of Quality & Safety Risk Assessment for Agro-products, Ministry of Agriculture, Yangling, China
| | - Xin Wang
- College of Food Science and Engineering, Northwest A&F University, Yangling, China.,Laboratory of Quality & Safety Risk Assessment for Agro-products, Ministry of Agriculture, Yangling, China
| | - Yuanyuan Gu
- College of Food Science and Engineering, Northwest A&F University, Yangling, China
| | - Yuzhu Zhao
- College of Food Science and Technology, Northwest University, Xi'an, China
| | - Yidi Wang
- College of Food Science and Engineering, Northwest A&F University, Yangling, China
| | - Tianli Yue
- College of Food Science and Engineering, Northwest A&F University, Yangling, China.,Laboratory of Quality & Safety Risk Assessment for Agro-products, Ministry of Agriculture, Yangling, China.,College of Food Science and Technology, Northwest University, Xi'an, China.,College of Enology, Northwest A&F University, Yangling, China
| | - Yahong Yuan
- College of Food Science and Engineering, Northwest A&F University, Yangling, China.,Laboratory of Quality & Safety Risk Assessment for Agro-products, Ministry of Agriculture, Yangling, China
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7
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Dhanamjayulu P, Boga RB, Mehta A. Inhibition of aflatoxin B1 biosynthesis and down regulation of aflR and aflB genes in presence of benzimidazole derivatives without impairing the growth of Aspergillus flavus. Toxicon 2019; 170:60-67. [PMID: 31541640 DOI: 10.1016/j.toxicon.2019.09.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/11/2019] [Accepted: 09/17/2019] [Indexed: 12/13/2022]
Abstract
Aflatoxins are mutagenic secondary metabolites produced by certain ubiquitous saprophytic fungi. These contaminate agricultural crops and pose a serious health threat to humans and livestock all over the world. Benzimidazole and its derivatives are biologically active heterocyclic compounds known for their fungicidal activity. In the present study, second and sixth position substituted benzimidazole derivatives are tested for their antifungal and anti-aflatoxigenic activity. Aflatoxigenic strain of Aspergillus flavus cultured in Yeast extract sucrose (YES) medium as well as in rice in the presence and absence of test compounds. 2-(2-Furyl) benzimidazole (FBD) showed complete inhibition of fungal growth at 50 μg/mL. However, the polar derivatives of FBD viz. 6-NFBD, 6-AFBD, 6-CAFBD, and 6-CFBD did not impair the fungal growth but effectively inhibited aflatoxin B1 biosynthesis. Significant down-regulation of aflR gene involved in regulation and aflB structural gene for aflatoxin B1 biosynthesis was observed in presence of 6-NFBD. These benzimidazole derivatives also showed good anti-aflatoxigenic activity in rice, though the IC50 concentrations in rice were comparatively higher than those in YES medium. This study summarizes the most notable structure-activity relationship (SAR) of 2-(2-Furyl) benzimidazoles for anti-aflatoxigenic and anti-fungal activities. These molecules can be further studied for their applications in industrial fermentation processes vulnerable to mold growth and subsequent aflatoxin B1 synthesis like koji fermentation, cheese production, etc.
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Affiliation(s)
- P Dhanamjayulu
- Department of Integrative Biology, School of Bio sciences and Technology, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India
| | | | - Alka Mehta
- Department of Integrative Biology, School of Bio sciences and Technology, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India.
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8
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Pennerman KK, Scarsella JB, Yin GH, Hua SST, Hartman TG, Bennett JW. Volatile 1-octen-3-ol increases patulin production by Penicillium expansum on a patulin-suppressing medium. Mycotoxin Res 2019; 35:329-340. [PMID: 31025195 DOI: 10.1007/s12550-019-00348-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 12/21/2022]
Abstract
1-Octen-3-ol is one of the most abundant volatile compounds associated with fungi and functions as a germination and growth inhibitor in several species. By investigating its effect on the biosynthesis of patulin, a mycotoxin made by Penicillium expansum, it was found that a sub-inhibitory level of volatile 1-octen-3-ol increased accumulation of patulin on a medium that normally suppresses the mycotoxin. Transcriptomic sequencing and comparisons of control and treated P. expansum grown on potato dextrose agar (PDA; patulin permissive) or secondary medium agar (SMA; patulin suppressive) revealed that the expression of gox2, a gene encoding a glucose oxidase, was significantly affected, decreasing 10-fold on PDA and increasing 85-fold on SMA. Thirty other genes, mostly involved in transmembrane transport, oxidation-reduction, and carbohydrate metabolism were also differently expressed on the two media. Transcription factors previously found to be involved in regulation of patulin biosynthesis were not significantly affected despite 1-octen-3-ol increasing patulin production on SMA. Further study is needed to determine the relationship between the upregulation of patulin biosynthesis genes and gox2 on SMA, and to identify the molecular mechanism by which 1-octen-3-ol induced this effect.
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Affiliation(s)
- Kayla K Pennerman
- Department of Plant Biology, Rutgers University, The State University of New Jersey, New Brunswick, NJ, 08901, USA.
| | - Joseph B Scarsella
- Department of Food Science, Rutgers University, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Guo-Hua Yin
- Department of Plant Biology, Rutgers University, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Sui-Sheng T Hua
- Foodborne Toxin Detection and Prevention Research, United States Department of Agriculture, Agricultural Research Service, Albany, CA, 94710, USA
| | - Thomas G Hartman
- Department of Food Science, Rutgers University, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Joan W Bennett
- Department of Plant Biology, Rutgers University, The State University of New Jersey, New Brunswick, NJ, 08901, USA
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9
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Yang M, Lu L, Li S, Zhang J, Li Z, Wu S, Guo Q, Liu H, Wang C. Transcriptomic Insights into Benzenamine Effects on the Development, Aflatoxin Biosynthesis, and Virulence of Aspergillus flavus. Toxins (Basel) 2019; 11:E70. [PMID: 30691218 PMCID: PMC6410012 DOI: 10.3390/toxins11020070] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 01/24/2019] [Accepted: 01/25/2019] [Indexed: 01/02/2023] Open
Abstract
Aspergillus flavus is a soilborne pathogenic fungus that poses a serious public health threat due to it contamination of food with carcinogenic aflatoxins. Our previous studies have demonstrated that benzenamine displayed strong inhibitory effects on the mycelial growth of A. flavus. In this study, we systematically investigated the inhibitory effects of benzenamine on the development, aflatoxin biosynthesis, and virulence in A. flavus, as well as the underlying mechanism. The results indicated that benzenamine exhibited great capacity to combat A. flavus at a concentration of 100 µL/L, leading to significantly decreased aflatoxin accumulation and colonization capacity in maize. The transcriptional profile revealed that 3589 genes show altered mRNA levels in the A. flavus after treatment with benzenamine, including 1890 down-regulated and 1699 up-regulated genes. Most of the differentially expressed genes participated in the biosynthesis and metabolism of amino acid, purine metabolism, and protein processing in endoplasmic reticulum. Additionally, the results brought us to a suggestion that benzenamine affects the development, aflatoxin biosynthesis, and pathogenicity of A. flavus via down-regulating related genes by depressing the expression of the global regulatory factor leaA. Overall, this study indicates that benzenamine have tremendous potential to act as a fumigant against pathogenic A. flavus. Furthermore, this work offers valuable information regarding the underlying antifungal mechanism of benzenamine against A. flavus at the level of transcription, and these potential targets may be conducive in developing new strategies for preventing aflatoxin contamination.
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Affiliation(s)
- Mingguan Yang
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Laifeng Lu
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Shuhua Li
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Jing Zhang
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Zhenjing Li
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Shufen Wu
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Qingbin Guo
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Huanhuan Liu
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Changlu Wang
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
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10
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Jiang H, Wang W, Ni X, Zhuang H, Yoon SC, Lawrence KC. Recent advancement in near infrared spectroscopy and hyperspectral imaging techniques for quality and safety assessment of agricultural and food products in the China Agricultural University. ACTA ACUST UNITED AC 2018. [DOI: 10.1177/0960336018804755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Near infrared spectroscopy and hyperspectral imaging are fast-growing, rapid, powerful, and non-destructive optical technologies that can be used especially in quality and safety control of agro-food products. The Non-destructive Detecting Laboratory for Agricultural and Food Products in the College of Engineering, China Agricultural University in Beijing, China, has engaged in research on sensing and characterizing agro-food quality and safety attributes with the latest optical methods including near infrared spectroscopy and hyperspectral imaging for over five years. In this report, some of our latest research and developments through multidisciplinary international collaborations will be highlighted to demonstrate our contributions to this near infrared spectroscopy and hyperspectral imaging sensing area to improve non-destructive diagnosis and quality control of agricultural and food products.
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Affiliation(s)
- Hongzhe Jiang
- College of Engineering, China Agricultural University, Beijing, China
| | - Wei Wang
- College of Engineering, China Agricultural University, Beijing, China
| | - Xinzhi Ni
- Crop Genetics and Breeding Research Unit, USDA-ARS, Tifton, GA, USA
| | - Hong Zhuang
- Quality & Safety Assessment Research Unit, U.S. National Poultry Research Center, USDA-ARS, Athens, GA, USA
| | - Seung-Chul Yoon
- Quality & Safety Assessment Research Unit, U.S. National Poultry Research Center, USDA-ARS, Athens, GA, USA
| | - Kurt C Lawrence
- Quality & Safety Assessment Research Unit, U.S. National Poultry Research Center, USDA-ARS, Athens, GA, USA
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11
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Lv C, Wang P, Ma L, Zheng M, Liu Y, Xing F. Large-Scale Comparative Analysis of Eugenol-Induced/Repressed Genes Expression in Aspergillus flavus Using RNA-seq. Front Microbiol 2018; 9:1116. [PMID: 29899734 PMCID: PMC5988903 DOI: 10.3389/fmicb.2018.01116] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 05/11/2018] [Indexed: 11/24/2022] Open
Abstract
Aflatoxin B1 (AFB1), which is mainly produced by Aspergillus flavus and Aspergillus parasiticus, is the most toxic and hepatocarcinogenic polyketide known. Chemical fungicides are currently utilized to reduce this fungal contaminant, but they are potentially harmful to human health and the environment. Therefore, natural anti-aflatoxigenic products are used as sustainable alternatives to control food and feed contamination. For example, eugenol, presents in many essential oils, has been identified as an aflatoxin inhibitor. However, its exact mechanism of inhibition is yet to be clarified. In this study, the anti-aflatoxigenic mechanism of eugenol in A. flavus was determined using a comparative transcriptomic approach. Twenty of twenty-nine genes in the aflatoxin biosynthetic pathway were down-regulated by eugenol. The most strongly down-regulated gene was aflMa, followed by aflI, aflJ, aflCa, aflH, aflNa, aflE, aflG, aflM, aflD, and aflP. However, the expression of the regulator gene aflR did not change significantly and the expression of aflS was slightly up-regulated. The down-regulation of the global regulator gene veA resulted in the up-regulation of srrA, and the down-regulation of ap-1 and mtfA. The early developmental regulator brlA was profoundly up-regulated in A. flavus after eugenol treatment. These results suggested a model in which eugenol improves fungal development by up-regulating the expression of brlA by the suppression of veA expression and inhibits aflatoxin production through the suppression of veA expression. Exposure to eugenol also caused dysregulated transcript levels of the G protein-coupled receptors (GPCRs) and oxylipins genes. A Gene Ontology analysis indicated that the genes that were highly responsive to eugenol were mainly enriched in RNA-binding functions, suggesting that post-transcriptional modification plays a pivotal role in aflatoxin biosynthesis. KEGG analysis showed that ribosome biogenesis was the most dysregulated pathway, suggesting that eugenol dysregulates ribosome biogenesis, which then interrupts the biosynthesis of Nor-1, Ver-1, and OmtA, and prevents aflatoxisomes performing their normal function in aflatoxin production. In conclusion, our results indicated that eugenol inhibited AFB1 production by modulating the expression of structural genes in aflatoxin pathway, fungal antioxidant status, post-transcriptional modifications and biosynthesis of backbone enzymes in A. flavus.
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Affiliation(s)
- Cong Lv
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Ping Wang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Longxue Ma
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Mumin Zheng
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Yang Liu
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Fuguo Xing
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
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12
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Padhi S, Dias I, Korn VL, Bennett JW. Pseudogymnoascus destructans: Causative Agent of White-Nose Syndrome in Bats Is Inhibited by Safe Volatile Organic Compounds. J Fungi (Basel) 2018; 4:jof4020048. [PMID: 29642609 PMCID: PMC6023378 DOI: 10.3390/jof4020048] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 03/27/2018] [Accepted: 04/03/2018] [Indexed: 01/12/2023] Open
Abstract
White-nose syndrome (WNS) is caused by Pseudogymnoascus destructans, a psychrophilic fungus that infects hibernating bats and has caused a serious decline in some species. Natural aroma compounds have been used to control growth of fungal food storage pathogens, so we hypothesized that a similar strategy could work for control of P. destructans. The effectiveness of exposure to low concentrations of the vapor phase of four of these compounds was tested on mycelial plugs and conidiospores at temperatures of 5, 10 and 15 °C. Here we report the efficacy of vapor phase mushroom alcohol (1-octen-3-ol) for inhibiting mycelial and conidiospore growth of P. destructans at 0.4 and 0.8 µmol/mL and demonstrate that the R enantiomer of this compound is more effective than the S enantiomer, supporting the finding that biological systems can be sensitive to stereochemistry. Further, we report that vapor phase leaf aldehyde (trans-2-hexenal), a common aroma compound associated with cut grass odors and also the major volatile compound in extra virgin olive oil, is more effective than mushroom alcohol. At 0.05 µmol/mL, trans-2-hexenal is fungicidal to both conidiospores and mycelia of P. destructans.
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Affiliation(s)
- Sally Padhi
- Department of Plant Biology, Rutgers University, 59 Dudley Road, New Brunswick, NJ 08901, USA.
| | - Itamar Dias
- Department of Plant Biology, Rutgers University, 59 Dudley Road, New Brunswick, NJ 08901, USA.
| | - Victoria L Korn
- Department of Plant Biology, Rutgers University, 59 Dudley Road, New Brunswick, NJ 08901, USA.
| | - Joan W Bennett
- Department of Plant Biology, Rutgers University, 59 Dudley Road, New Brunswick, NJ 08901, USA.
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13
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El Khoury R, Caceres I, Puel O, Bailly S, Atoui A, Oswald IP, El Khoury A, Bailly JD. Identification of the Anti-Aflatoxinogenic Activity of Micromeria graeca and Elucidation of Its Molecular Mechanism in Aspergillus flavus. Toxins (Basel) 2017; 9:toxins9030087. [PMID: 28257049 PMCID: PMC5371842 DOI: 10.3390/toxins9030087] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 02/22/2017] [Accepted: 02/24/2017] [Indexed: 01/25/2023] Open
Abstract
Of all the food-contaminating mycotoxins, aflatoxins, and most notably aflatoxin B1 (AFB1), are found to be the most toxic and economically costly. Green farming is striving to replace fungicides and develop natural preventive strategies to minimize crop contamination by these toxic fungal metabolites. In this study, we demonstrated that an aqueous extract of the medicinal plant Micromeria graeca—known as hyssop—completely inhibits aflatoxin production by Aspergillus flavus without reducing fungal growth. The molecular inhibitory mechanism was explored by analyzing the expression of 61 genes, including 27 aflatoxin biosynthesis cluster genes and 34 secondary metabolism regulatory genes. This analysis revealed a three-fold down-regulation of aflR and aflS encoding the two internal cluster co-activators, resulting in a drastic repression of all aflatoxin biosynthesis genes. Hyssop also targeted fifteen regulatory genes, including veA and mtfA, two major global-regulating transcription factors. The effect of this extract is also linked to a transcriptomic variation of several genes required for the response to oxidative stress such as msnA, srrA, catA, cat2, sod1, mnsod, and stuA. In conclusion, hyssop inhibits AFB1 synthesis at the transcriptomic level. This aqueous extract is a promising natural-based solution to control AFB1 contamination.
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Affiliation(s)
- Rhoda El Khoury
- Toxalim, Université de Toulouse, INRA, ENVT, INP Purpan, UPS, Toulouse F-31027, France.
- Laboratoire de Mycologie et Sécurité des Aliments (LMSA), Département des sciences de la vie et de la terres - Biochimie, Faculté des Sciences, Université Saint-Joseph, P.O. Box 17-5208, Mar Mikhael Beirut 1104 2020 Lebanon.
| | - Isaura Caceres
- Toxalim, Université de Toulouse, INRA, ENVT, INP Purpan, UPS, Toulouse F-31027, France.
| | - Olivier Puel
- Toxalim, Université de Toulouse, INRA, ENVT, INP Purpan, UPS, Toulouse F-31027, France.
| | - Sylviane Bailly
- Toxalim, Université de Toulouse, INRA, ENVT, INP Purpan, UPS, Toulouse F-31027, France.
| | - Ali Atoui
- Laboratory of Microbiology, Department of Natural Sciences and Earth, Faculty of Sciences I, Lebanese University, Hadath Campus, P.O. Box 5, Beirut, Lebanon.
| | - Isabelle P Oswald
- Toxalim, Université de Toulouse, INRA, ENVT, INP Purpan, UPS, Toulouse F-31027, France.
| | - André El Khoury
- Laboratoire de Mycologie et Sécurité des Aliments (LMSA), Département des sciences de la vie et de la terres - Biochimie, Faculté des Sciences, Université Saint-Joseph, P.O. Box 17-5208, Mar Mikhael Beirut 1104 2020 Lebanon.
| | - Jean-Denis Bailly
- Toxalim, Université de Toulouse, INRA, ENVT, INP Purpan, UPS, Toulouse F-31027, France.
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14
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Liang D, Xing F, Selvaraj JN, Liu X, Wang L, Hua H, Zhou L, Zhao Y, Wang Y, Liu Y. Inhibitory Effect of Cinnamaldehyde, Citral, and Eugenol on Aflatoxin Biosynthetic Gene Expression and Aflatoxin B1 Biosynthesis in Aspergillus flavus. J Food Sci 2015; 80:M2917-24. [PMID: 26556681 DOI: 10.1111/1750-3841.13144] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 10/12/2015] [Indexed: 11/27/2022]
Abstract
In order to reveal the inhibitory effects of cinnamaldehyde, citral, and eugenol on aflatoxin biosynthesis, the expression levels of 5 key aflatoxin biosynthetic genes were evaluated by real-time PCR. Aspergillus flavus growth and AFB1 production were completely inhibited by 0.80 mmol/L of cinnamaldehyde and 2.80 mmol/L of citral. However, at lower concentration, cinnamaldehyde (0.40 mmol/L), eugenol (0.80 mmol/L), and citral (0.56 mmol/L) significantly reduced AFB1 production with inhibition rate of 68.9%, 95.4%, and 41.8%, respectively, while no effect on fungal growth. Real-time PCR showed that the expressions of aflR, aflT, aflD, aflM, and aflP were down-regulated by cinnamaldehyde (0.40 mmol/L), eugenol (0.80 mmol/L), and citral (0.56 mmol/L). In the presence of cinnamaldehyde, AflM was highly down-regulated (average of 5963 folds), followed by aflP, aflR, aflD, and aflT with the average folds of 55, 18, 6.5, and 5.8, respectively. With 0.80 mmol/L of eugenol, aflP was highly down-regulated (average of 2061-folds), followed by aflM, aflR, aflD, and aflT with average of 138-, 15-, 5.2-, and 4.8-folds reduction, respectively. With 0.56 mmol/L of citral, aflT was completely inhibited, followed by aflM, aflP, aflR, and aflD with average of 257-, 29-, 3.5-, and 2.5-folds reduction, respectively. These results suggest that the reduction in AFB1 production by cinnamaldehyde, eugenol, and citral at low concentration may be due to the down-regulations of the transcription level of aflatoxin biosynthetic genes. Cinnamaldehyde and eugenol may be employed successfully as a good candidate in controlling of toxigenic fungi and subsequently contamination with aflatoxins in practice.
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Affiliation(s)
- Dandan Liang
- Inst. of Food Science and Technology, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-products Processing, Ministry of Agriculture, Beijing, 100193, P. R. China
| | - Fuguo Xing
- Inst. of Food Science and Technology, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-products Processing, Ministry of Agriculture, Beijing, 100193, P. R. China
| | - Jonathan Nimal Selvaraj
- Inst. of Food Science and Technology, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-products Processing, Ministry of Agriculture, Beijing, 100193, P. R. China
| | - Xiao Liu
- Inst. of Food Science and Technology, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-products Processing, Ministry of Agriculture, Beijing, 100193, P. R. China
| | - Limin Wang
- Inst. of Food Science and Technology, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-products Processing, Ministry of Agriculture, Beijing, 100193, P. R. China
| | - Huijuan Hua
- Inst. of Food Science and Technology, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-products Processing, Ministry of Agriculture, Beijing, 100193, P. R. China
| | - Lu Zhou
- Inst. of Food Science and Technology, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-products Processing, Ministry of Agriculture, Beijing, 100193, P. R. China
| | - Yueju Zhao
- Inst. of Food Science and Technology, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-products Processing, Ministry of Agriculture, Beijing, 100193, P. R. China
| | - Yan Wang
- Inst. of Food Science and Technology, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-products Processing, Ministry of Agriculture, Beijing, 100193, P. R. China
| | - Yang Liu
- Inst. of Food Science and Technology, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-products Processing, Ministry of Agriculture, Beijing, 100193, P. R. China
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15
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Chang PK, Hua SST, Sarreal SBL, Li RW. Suppression of Aflatoxin Biosynthesis in Aspergillus flavus by 2-Phenylethanol Is Associated with Stimulated Growth and Decreased Degradation of Branched-Chain Amino Acids. Toxins (Basel) 2015; 7:3887-902. [PMID: 26404375 PMCID: PMC4626709 DOI: 10.3390/toxins7103887] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/02/2015] [Accepted: 09/17/2015] [Indexed: 11/30/2022] Open
Abstract
The saprophytic soil fungus Aspergillus flavus infects crops and produces aflatoxin. Pichia anomala, which is a biocontrol yeast and produces the major volatile 2-phenylethanol (2-PE), is able to reduce growth of A. flavus and aflatoxin production when applied onto pistachio trees. High levels of 2-PE are lethal to A. flavus and other fungi. However, at low levels, the underlying mechanism of 2-PE to inhibit aflatoxin production remains unclear. In this study, we characterized the temporal transcriptome response of A. flavus to 2-PE at a subinhibitory level (1 µL/mL) using RNA-Seq technology and bioinformatics tools. The treatment during the entire 72 h experimental period resulted in 131 of the total A. flavus 13,485 genes to be significantly impacted, of which 82 genes exhibited decreased expression. They included those encoding conidiation proteins and involved in cyclopiazonic acid biosynthesis. All genes in the aflatoxin gene cluster were also significantly decreased during the first 48 h treatment. Gene Ontology (GO) analyses showed that biological processes with GO terms related to catabolism of propionate and branched-chain amino acids (valine, leucine and isoleucine) were significantly enriched in the down-regulated gene group, while those associated with ribosome biogenesis, translation, and biosynthesis of α-amino acids were over-represented among the up-regulated genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that metabolic pathways negatively impacted among the down-regulated genes parallel to those active at 30 °C, a condition conducive to aflatoxin biosynthesis. In contrast, metabolic pathways positively related to the up-regulated gene group resembled those at 37 °C, which favors rapid fungal growth and is inhibitory to aflatoxin biosynthesis. The results showed that 2-PE at a low level stimulated active growth of A. flavus but concomitantly rendered decreased activities in branched-chain amino acid degradation. Since secondary metabolism occurs after active growth has ceased, this growth stimulation resulted in suppression of expression of aflatoxin biosynthesis genes. On the other hand, increased activities in degradation pathways for branched-chain amino acids probably are required for the activation of the aflatoxin pathway by providing building blocks and energy regeneration. Metabolic flux in primary metabolism apparently has an important role in the expression of genes of secondary metabolism.
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Affiliation(s)
- Perng-Kuang Chang
- Southern Regional Research Center, Agricultural Research Service, U. S. Department of Agriculture, New Orleans, LA 70124, USA.
| | - Sui Sheng T Hua
- Western Regional Research Center, Agricultural Research Service, U. S. Department of Agriculture, Albany, CA 94710, USA.
| | - Siov Bouy L Sarreal
- Western Regional Research Center, Agricultural Research Service, U. S. Department of Agriculture, Albany, CA 94710, USA.
| | - Robert W Li
- Animal Genomics and Improvement Laboratory, Agricultural Research Service, U. S. Department of Agriculture, Beltsville, MD 20705, USA.
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16
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Genome-Wide Transcriptome Analysis of Cotton (Gossypium hirsutum L.) Identifies Candidate Gene Signatures in Response to Aflatoxin Producing Fungus Aspergillus flavus. PLoS One 2015; 10:e0138025. [PMID: 26366857 PMCID: PMC4569580 DOI: 10.1371/journal.pone.0138025] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 08/24/2015] [Indexed: 11/19/2022] Open
Abstract
Aflatoxins are toxic and potent carcinogenic metabolites produced from the fungi Aspergillus flavus and A. parasiticus. Aflatoxins can contaminate cottonseed under conducive preharvest and postharvest conditions. United States federal regulations restrict the use of aflatoxin contaminated cottonseed at >20 ppb for animal feed. Several strategies have been proposed for controlling aflatoxin contamination, and much success has been achieved by the application of an atoxigenic strain of A. flavus in cotton, peanut and maize fields. Development of cultivars resistant to aflatoxin through overexpression of resistance associated genes and/or knocking down aflatoxin biosynthesis of A. flavus will be an effective strategy for controlling aflatoxin contamination in cotton. In this study, genome-wide transcriptome profiling was performed to identify differentially expressed genes in response to infection with both toxigenic and atoxigenic strains of A. flavus on cotton (Gossypium hirsutum L.) pericarp and seed. The genes involved in antifungal response, oxidative burst, transcription factors, defense signaling pathways and stress response were highly differentially expressed in pericarp and seed tissues in response to A. flavus infection. The cell-wall modifying genes and genes involved in the production of antimicrobial substances were more active in pericarp as compared to seed. The genes involved in auxin and cytokinin signaling were also induced. Most of the genes involved in defense response in cotton were highly induced in pericarp than in seed. The global gene expression analysis in response to fungal invasion in cotton will serve as a source for identifying biomarkers for breeding, potential candidate genes for transgenic manipulation, and will help in understanding complex plant-fungal interaction for future downstream research.
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17
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Effects of Three Volatile Oxylipins on Colony Development in Two Species of Fungi and on Drosophila Larval Metamorphosis. Curr Microbiol 2015; 71:347-56. [PMID: 26126831 DOI: 10.1007/s00284-015-0864-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 05/19/2015] [Indexed: 02/03/2023]
Abstract
The aim of this study is to investigate the effects of three volatile oxylipins on colony development in two fungi and on Drosophila larval metamorphosis. Using an airborne exposure technique, three common and volatile oxylipins (1-octen-3-ol, (E)-2-hexenal, and 1-hexanol) were compared for their effects on spore germination and colony growth in Aspergillus niger and Penicillium chrysogenum, as well as for their effects on the morphogenesis of larvae of Drosophila melanogaster. Conidia of both A. niger and P. chrysogenum plated in the presence of low concentrations (50 ppm) of these three volatile organic compounds (VOCs) formed fewer colony-forming units (CFUs) and exhibited reduced radial growth of colonies as compared to controls. When A. niger and P. chrysogenum spores were germinated in the presence of the enantiomers of 1-octen-3-ol, (R)-(-)-1-octen-3-ol had the greatest impact on colony morphology (decreased sporulation and colony diameter), while (S)-(+)-1-octen-3-ol and the racemic form yielded similar morphological changes but to a lesser extent. In addition, Drosophila larvae exposed to vapors of these oxylipins exhibited serious delays in metamorphosis and toxic effects on pupae and adult stages. Low concentration of these three VOCs can significantly inhibit the formation of CFUs and the growth of fungi. (R)-(-)-1-octen-3-ol imposed the greatest impact on fungal morphology compared to (S)-(+)-1-octen-3-ol and the racemic form. The three volatile oxylipins could also delay the metamorphosis of Drosophila and impose toxic effects on its pupae and adult stages.
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18
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Wang W, Lawrence KC, Ni X, Yoon SC, Heitschmidt GW, Feldner P. Near-infrared hyperspectral imaging for detecting Aflatoxin B1 of maize kernels. Food Control 2015. [DOI: 10.1016/j.foodcont.2014.11.047] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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Wang W, Heitschmidt GW, Windham WR, Feldner P, Ni X, Chu X. Feasibility of Detecting Aflatoxin B1on Inoculated Maize Kernels Surface using Vis/NIR Hyperspectral Imaging. J Food Sci 2014; 80:M116-22. [DOI: 10.1111/1750-3841.12728] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 10/29/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Wei Wang
- College of Engineering, China Agricultural Univ; No. 17 Tsinghua East Rd. Beijing 100083 China
| | - Gerald W. Heitschmidt
- Quality & Safety Assessment Research Unit; Richard B. Russell Research Center; USDA-ARS, 950 College Station Rd. Athens GA 30605 U.S.A
| | - William R. Windham
- Quality & Safety Assessment Research Unit; Richard B. Russell Research Center; USDA-ARS, 950 College Station Rd. Athens GA 30605 U.S.A
| | - Peggy Feldner
- Quality & Safety Assessment Research Unit; Richard B. Russell Research Center; USDA-ARS, 950 College Station Rd. Athens GA 30605 U.S.A
| | - Xinzhi Ni
- Crop Genetics and Breeding Research Unit-USDA-ARS; 2747 Davis Road Tifton GA 31793 U.S.A
| | - Xuan Chu
- College of Engineering, China Agricultural Univ; No. 17 Tsinghua East Rd. Beijing 100083 China
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20
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Chang PK, Scharfenstein LL, Mack B, Yu J, Ehrlich KC. Transcriptomic profiles of Aspergillus flavus CA42, a strain that produces small sclerotia, by decanal treatment and after recovery. Fungal Genet Biol 2014; 68:39-47. [DOI: 10.1016/j.fgb.2014.04.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/08/2014] [Accepted: 04/15/2014] [Indexed: 01/12/2023]
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21
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Hua SST, Beck JJ, Sarreal SBL, Gee W. The major volatile compound 2-phenylethanol from the biocontrol yeast, Pichia anomala, inhibits growth and expression of aflatoxin biosynthetic genes of Aspergillus flavus. Mycotoxin Res 2014; 30:71-8. [PMID: 24504634 DOI: 10.1007/s12550-014-0189-z] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 01/13/2014] [Accepted: 01/16/2014] [Indexed: 11/28/2022]
Abstract
Aspergillus flavus is a ubiquitous saprophyte that is able to produce the most potent natural carcinogenic compound known as aflatoxin B1 (AFB1). This toxin frequently contaminates crops including corn, cotton, peanuts, and tree nuts causing substantial economic loss worldwide. Consequently, more than 100 countries have strict regulations limiting AFB1 in foodstuffs and feedstuffs. Plants and microbes are able to produce volatile compounds that act as a defense mechanism against other organisms. Pichia anomala strain WRL-076 is a biocontrol yeast currently being tested to reduce AF contamination of tree nuts in California. We used the SPME-GC/MS analysis and identified the major volatile compound produced by this strain to be 2-phenylethanol (2-PE). It inhibited spore germination and AF production of A. flavus. Inhibition of AF formation by 2-PE was correlated with significant down regulation of clustering AF biosynthesis genes as evidenced by several to greater than 10,000-fold decrease in gene expression. In a time-course analysis we found that 2-PE also altered the expression patterns of chromatin modifying genes, MYST1, MYST2, MYST3, gcn5, hdaA and rpdA. The biocontrol capacity of P. anomala can be attributed to the production of 2-PE, which affects spore germination, growth, toxin production, and gene expression in A. flavus.
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Affiliation(s)
- Sui Sheng T Hua
- U. S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, 800 Buchanan Street, Albany, CA, 94710, USA,
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22
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Yahyaraeyat R, Khosravi AR, Shahbazzadeh D, Khalaj V. The potential effects of Zataria multiflora Boiss essential oil on growth, aflatoxin production and transcription of aflatoxin biosynthesis pathway genes of toxigenic Aspergillus parasiticus. Braz J Microbiol 2013; 44:643-9. [PMID: 24294264 PMCID: PMC3833170 DOI: 10.1590/s1517-83822013000200045] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 06/05/2012] [Indexed: 11/22/2022] Open
Abstract
This study aims at evaluating the effects of Zataria multiflora (Z. multiflora) essential oil (EO) on growth, aflatoxin production and transcription of aflatoxin biosynthesis pathway genes. Total RNAs of Aspergillus parasiticus (A.parasiticus) ATCC56775 grown in yeast extract sucrose (YES) broth medium treated with Z. multiflora EO were subjected to reverse transcription- polymerase chain reaction (RT-PCR). Specific primers of nor-1, ver-1, omt-A and aflR genes were used. In parallel mycelial dry weight of samples were measured and all the media were assayed by high-pressure liquid chromatography (HPLC) for aflatoxinB1 (AFB1), aflatoxinB2 (AFB2), aflatoxinG1 (AFG1), aflatoxinG2 (AFG2) and aflatoxin total (AFTotal) production. The results showed that mycelial dry weight and aflatoxin production reduce in the presence of Z. multiflora EO (100 ppm) on day 5 of growth. It was found that the expression of nor-1, ver-1, omt-A and aflR genes was correlated with the ability of fungus to produce aflatoxins on day 5 in YES medium. RT-PCR showed that in the presence of Z.multiflora EO (100 ppm) nor-1, ver-1 and omtA genes expression was reduced. It seems that toxin production inhibitory effects of Z. multiflora EO on day 5 may be at the transcription level and this herb may cause reduction in aflatoxin biosynthesis pathway genes activity.
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Affiliation(s)
- R Yahyaraeyat
- Mycology Research Centre, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
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23
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Walley JW, Kliebenstein DJ, Bostock RM, Dehesh K. Fatty acids and early detection of pathogens. CURRENT OPINION IN PLANT BIOLOGY 2013; 16:520-6. [PMID: 23845737 DOI: 10.1016/j.pbi.2013.06.011] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 06/11/2013] [Accepted: 06/13/2013] [Indexed: 05/20/2023]
Abstract
Early in interactions between plants and pathogens, plants recognize molecular signatures in microbial cells, triggering a form of immunity that may help resist infection and colonization by pathogens. Diverse molecules provide these molecular signatures, called pathogen-associated molecular patterns (PAMPs), including proteins, polysaccharides, and lipids. Before and concurrent with the onset of PAMP-triggered immunity, there are alterations in plant membrane lipid composition, modification of membrane fluidity through desaturase-mediated changes in unsaturated fatty acid levels, and enzymatic and non-enzymatic genesis of bioactive lipid mediators such as oxylipins. These complex lipid changes produce a myriad of potential molecular signatures that are beginning to be found to have key roles in the regulation of transcriptional networks. Further, research on fatty acid action in various biological contexts, including plant-pathogen interactions and stress network signaling, is needed to fully understand fatty acids as regulatory signals that transcend their established role in membrane structure and function.
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Affiliation(s)
- Justin W Walley
- Department of Plant Biology, University of California, Davis, CA 95616, USA
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24
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Canavar Ö, Kaynak MA. Prevention of pre-harvest aflatoxin production and the effect of different harvest times on peanut (Arachis hypogaea L.) fatty acids. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2013; 30:1807-18. [PMID: 23889477 DOI: 10.1080/19440049.2013.818720] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The aim of this study was to investigate the relationship between aflatoxin and fatty acids and to determine the optimum harvest time to avoid pre-harvest aflatoxin formation. It was established that harvest time had statistically significant effects on the levels of saturated fatty acids: myristic acid (C14:0), palmitic acid (C16:0), heptadecanoic acid (C17:0), stearic acid (C18:0), arachidic acid (C20:0), behenic acid (C22:0), lignoceric acid (C24:0), monounsaturated fatty acids; palmitoleic acid (C16:1), heptadecenoic acid (C17:1), oleic acid (C18:1) and gadoleic acid (C20:1); and on polyunsaturated fatty acids: linoleic acid (C18:2) and linolenic acid (C18:3). By delaying the harvest time, the ratio of saturated fatty acids decreased and unsaturated fatty acids increased. It was shown that the longer harvesting was delayed, the greater the quantity of oleic acid that was produced. Before harvest time, if the soil moisture was 5% or higher, aflatoxin was produced by fungi. It was found that the weather conditions of the region were suitable for aflatoxin production. Soil moisture appears to be more important than soil temperature for aflatoxin formation. The production of aflatoxin was not observed in the first and second harvests, both of which are at early harvest times. It was found that aflatoxin B1 during harvest time was the most significant of the four toxins. The third harvest time, which is the most widely used, was observed to have significant problems due to aflatoxin formation. Therefore, it is suggested as a result of this study that the harvest of peanuts must be done considering seed yield before the middle of September to avoid aflatoxin formation at harvest time.
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Affiliation(s)
- Öner Canavar
- a Department of Crop Science , Faculty of Agriculture, Adnan Menderes University , Aydın , Turkey
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Affiliation(s)
| | | | - John E. Linz
- Department of Food Science and Human Nutrition,
- Department of Microbiology and Molecular Genetics,
- National Food Safety and Toxicology Center,
- Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824;
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Yu J. Current understanding on aflatoxin biosynthesis and future perspective in reducing aflatoxin contamination. Toxins (Basel) 2012; 4:1024-57. [PMID: 23202305 PMCID: PMC3509697 DOI: 10.3390/toxins4111024] [Citation(s) in RCA: 197] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 10/08/2012] [Accepted: 10/09/2012] [Indexed: 01/20/2023] Open
Abstract
Traditional molecular techniques have been used in research in discovering the genes and enzymes that are involved in aflatoxin formation and genetic regulation. We cloned most, if not all, of the aflatoxin pathway genes. A consensus gene cluster for aflatoxin biosynthesis was discovered in 2005. The factors that affect aflatoxin formation have been studied. In this report, the author summarized the current status of research progress and future possibilities that may be used for solving aflatoxin contamination.
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Affiliation(s)
- Jiujiang Yu
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture (USDA/ARS), New Orleans, LA 70112, USA.
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27
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Roze LV, Beaudry RM, Linz JE. Analysis of volatile compounds emitted by filamentous fungi using solid-phase microextraction-gas chromatography/mass spectrometry. Methods Mol Biol 2012; 944:133-42. [PMID: 23065613 DOI: 10.1007/978-1-62703-122-6_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Here, we describe a solid-phase microextraction-gas chromatography/mass spectrometry (SPME-GC/MS) analytical approach that identifies and analyzes volatile compounds in the headspace above a live fungal culture. This approach is a sensitive, solvent-free, robust technique; most importantly from a practical standpoint, this approach is noninvasive and requires minimal sample handling. Aliquots of liquid fungal cultures are placed into vials equipped with inert septa and equilibrated at a constant temperature, and headspace gases are sampled using an SPME fiber inserted through the septum into the headspace above the fungal culture for a standardized period of time. The outer polymer coating of a fused silica fiber absorbs volatiles from the headspace; the volatiles are then desorbed in the hot GC inlet and chromatographed in the usual manner. The separated compounds are subsequently identified by mass spectrometry. All steps in volatile profiling of a single sample from volatile sorption on a fiber to obtaining a list of volatiles can take as little as 15 min or can be extended to several hours if longer sorption is required for compounds present at very low levels and/or have low rates of diffusion.
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Affiliation(s)
- Ludmila V Roze
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI, USA.
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28
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Abbas HK, Weaver MA, Horn BW, Carbone I, Monacell JT, Shier WT. Selection ofAspergillus flavusisolates for biological control of aflatoxins in corn. TOXIN REV 2011. [DOI: 10.3109/15569543.2011.591539] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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29
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Cary JW, Rajasekaran K, Brown RL, Luo M, Chen ZY, Bhatnagar D. Developing resistance to aflatoxin in maize and cottonseed. Toxins (Basel) 2011; 3:678-96. [PMID: 22069734 PMCID: PMC3202838 DOI: 10.3390/toxins3060678] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 06/14/2011] [Accepted: 06/16/2011] [Indexed: 11/26/2022] Open
Abstract
At this time, no "magic bullet" for solving the aflatoxin contamination problem in maize and cottonseed has been identified, so several strategies must be utilized simultaneously to ensure a healthy crop, free of aflatoxins. The most widely explored strategy for the control of aflatoxin contamination is the development of preharvest host resistance. This is because A. flavus infects and produces aflatoxins in susceptible crops prior to harvest. In maize production, the host resistance strategy has gained prominence because of advances in the identification of natural resistance traits. However, native resistance in maize to aflatoxin contamination is polygenic and complex and, therefore, markers need to be identified to facilitate the transfer of resistance traits into agronomically viable genetic backgrounds while limiting the transfer of undesirable traits. Unlike maize, there are no known cotton varieties that demonstrate enhanced resistance to A. flavus infection and aflatoxin contamination. For this reason, transgenic approaches are being undertaken in cotton that utilize genes encoding antifungal/anti-aflatoxin factors from maize and other sources to counter fungal infection and toxin production. This review will present information on preharvest control strategies that utilize both breeding and native resistance identification approaches in maize as well as transgenic approaches in cotton.
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Affiliation(s)
- Jeffrey W. Cary
- United States Department of Agriculture-Agriculture Research Service, Southern Regional Research Center, New Orleans, LA 70124, USA; (K.R.); (R.L.B.); (M.L.); (D.B.)
| | - Kanniah Rajasekaran
- United States Department of Agriculture-Agriculture Research Service, Southern Regional Research Center, New Orleans, LA 70124, USA; (K.R.); (R.L.B.); (M.L.); (D.B.)
| | - Robert L. Brown
- United States Department of Agriculture-Agriculture Research Service, Southern Regional Research Center, New Orleans, LA 70124, USA; (K.R.); (R.L.B.); (M.L.); (D.B.)
| | - Meng Luo
- United States Department of Agriculture-Agriculture Research Service, Southern Regional Research Center, New Orleans, LA 70124, USA; (K.R.); (R.L.B.); (M.L.); (D.B.)
| | - Zhi-Yuan Chen
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA;
| | - Deepak Bhatnagar
- United States Department of Agriculture-Agriculture Research Service, Southern Regional Research Center, New Orleans, LA 70124, USA; (K.R.); (R.L.B.); (M.L.); (D.B.)
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30
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Roze LV, Koptina AV, Laivenieks M, Beaudry RM, Jones DA, Kanarsky AV, Linz JE. Willow volatiles influence growth, development, and secondary metabolism in Aspergillus parasiticus. Appl Microbiol Biotechnol 2011; 92:359-70. [PMID: 21614501 DOI: 10.1007/s00253-011-3339-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 04/08/2011] [Accepted: 04/13/2011] [Indexed: 12/22/2022]
Abstract
Aflatoxin is a mycotoxin and the most potent naturally occurring carcinogen in many animals. Aflatoxin contamination of food and feed crops causes a significant global burden on human and animal health. However, available methods to eliminate aflatoxin from food and feed are not fully effective. Our goal is to discover novel, efficient, and practical methods to control aflatoxin contamination in crops during storage. In the present study, we tested the effect of volatiles produced by willow (Salix acutifolia and Salix babylonica) and maple (Acer saccharinum) bark on fungal growth, development, and aflatoxin production by the fungus Aspergillus parasiticus, one economically important aflatoxin producer. S. acutifolia bark volatiles nearly eliminated aflatoxin accumulation (>90% reduction) by A. parasiticus grown on a minimal agar medium. The decrease in aflatoxin accumulation correlated with a twofold reduction in ver-1 (encodes a middle aflatoxin pathway enzyme) transcript level. Expression data also indicate that one histone H4 acetyltransferase, MYST3, may play a role in epigenetic control of aflatoxin gene transcription in response to volatile exposure. Volatiles derived from wood bark samples also increased fungal growth up to 20% and/or enhanced conidiospore development. Solid-phase microextraction-gas chromatographic-mass spectrometric analysis of bark samples identified sets of shared and unique volatile compounds that may mediate the observed regulatory effects on growth, development, and aflatoxin synthesis. This work provides an experimental basis for the use of willow industry by-products to control aflatoxin contamination in food and feed crops.
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Affiliation(s)
- Ludmila V Roze
- Food Science and Human Nutrition Department, Michigan State University, 227 GM Trout Bldg, East Lansing, MI 48824, USA.
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31
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The lipid language of plant-fungal interactions. Fungal Genet Biol 2010; 48:4-14. [PMID: 20519150 DOI: 10.1016/j.fgb.2010.05.005] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 05/12/2010] [Accepted: 05/12/2010] [Indexed: 11/20/2022]
Abstract
Lipid mediated cross-kingdom communication between hosts and pathogens is a rapidly emerging field in molecular plant-fungal interactions. Amidst our growing understanding of fungal and plant chemical cross-talk lies the distinct, yet little studied, role for a group of oxygenated lipids derived from polyunsaturated fatty acids, termed oxylipins. Endogenous fungal oxylipins are known for their roles in carrying out pathogenic strategies to successfully colonize their host, reproduce, and synthesize toxins. While plant oxylipins also have functions in reproduction and development, they are largely recognized as agents that facilitate resistance to pathogen attack. Here we review the composition and endogenous functions of oxylipins produced by both plants and fungi and introduce evidence which suggests that fungal pathogens exploit host oxylipins to facilitate their own virulence and pathogenic development. Specifically, we describe how fungi induce plant lipid metabolism to utilize plant oxylipins in order to promote G-protein-mediated regulation of sporulation and mycotoxin production in the fungus. The use of host-ligand mimicry (i.e. coronatine) to manipulate plant defense responses that benefit the fungus are also implicated.
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32
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Menniti A, Gregori R, Neri F. Activity of natural compounds on Fusarium verticillioides and fumonisin production in stored maize kernels. Int J Food Microbiol 2010; 136:304-9. [DOI: 10.1016/j.ijfoodmicro.2009.10.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 09/18/2009] [Accepted: 10/09/2009] [Indexed: 11/25/2022]
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33
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Gao X, Kolomiets MV. Host-derived lipids and oxylipins are crucial signals in modulating mycotoxin production by fungi. TOXIN REV 2009. [DOI: 10.1080/15569540802420584] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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34
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Cleveland TE, Carter-Wientjes CH, De Lucca AJ, Boué SM. Effect of soybean volatile compounds on Aspergillus flavus growth and aflatoxin production. J Food Sci 2009; 74:H83-7. [PMID: 19323756 DOI: 10.1111/j.1750-3841.2009.01078.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Soybean homogenates produced volatile compounds upon exposure to lipase. These induced volatiles were identified by SPME. Seventeen volatile compounds identified by SPME were chosen for determination of their ability to inhibit Aspergillus flavus growth and aflatoxin B(1) (AFB1) production in a solid media assay. These volatiles included aldehydes, alcohols, ketones, and furans. Of the tested compounds, the aldehydes showed the greatest inhibition of fungal growth and AFB1 production. These compounds inhibited up to 100% of the observed growth and AFB1 production as compared to the controls. The greatest activity by the aldehydes to disrupt growth was ranked as follows: 2,4 hexadienal > benzaldehyde > 2-octenal > (E)-2-heptenal > octanal > (E)-2-hexenal > nonanal > hexanal. The greatest activity by the aldehydes to reduce AFB1 was ranked as follows: (E)-2-hexenal > 2,4 hexadienal > (E)-2-heptenal > hexanal > nonanal. (E)-2-hexenal and (E)-2-heptenal were tested further in an A. flavus-inoculated corn kernel assay. Both compounds prevented colonization by A. flavus and eliminated AFB1 production when exposed to compound volumes < 10 muL as also shown in the solid media assay. The results suggest that soybeans react to lipase by production of potent antifungal volatiles.
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Affiliation(s)
- T E Cleveland
- US Dept of Agriculture, Southern Regional Research Center, Agricultural Research Service, New Orleans, LA 70179, USA
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35
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Losada L, Ajayi O, Frisvad JC, Yu J, Nierman WC. Effect of competition on the production and activity of secondary metabolites in Aspergillus species. Med Mycol 2009; 47 Suppl 1:S88-96. [PMID: 19255906 DOI: 10.1080/13693780802409542] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Secondary metabolites are of intense interest to humans due to their pharmaceutical and/or toxic properties. Also, these metabolites are clinically relevant because of their importance in fungal pathogenesis. Aspergillus species secrete secondary metabolites when grown individually and in the presence of other fungal species. However, it is not known whether secreted secondary metabolites provide a competitive advantage over other fungal species, or whether competition has any effect on the production of those metabolites. Here, we have performed co-cultivation competition assays among different species of Aspergillus to determine relative species fitness in culture, and to analyze the presence of possible antifungal activity of secondary metabolites in extracts. The results show that, for the most part, at 30 degrees C only one species is able to survive direct competition with a second species. In contrast, survival of both competitors was often observed at 37 degrees C. Consistent with these observations, antifungal activity of extracts from cultures grown at 30 degrees C was greater than that of extract from cultures at 37 degrees C. Interestingly, culture extracts from all species studied had some degree of antifungal activity, but in general, the extracts had greater antifungal activity when species were grown in the presence of a competitor. Using gas chromatography it was determined that the composition of extracts changed due to competition and a shift in temperature. These findings indicate that co-cultivation could be a very promising method for inducing and characterizing novel antifungal compounds produced by species of Aspergillus.
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Affiliation(s)
- Liliana Losada
- J. Craig Venter Institute, Rockville, Maryland 20850, USA
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36
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37
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Gramss G, Bergmann H. Role of plants in the vegetative and reproductive growth of saprobic basidiomycetous ground fungi. MICROBIAL ECOLOGY 2008; 56:660-670. [PMID: 18506502 DOI: 10.1007/s00248-008-9385-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Revised: 01/17/2008] [Accepted: 03/12/2008] [Indexed: 05/26/2023]
Abstract
Non-symbiotic microorganisms engineered or expensively selected to degrade xenobiotic hydrocarbons or modify heavy-metal uptake of plants in soil remediations die back after their introduction into the target soils. Mycelia of saprobic basidiomycetes were therefore inoculated into soil samples of 1 l in glass vessels to record mycelial growth and reproduction in the immediate rhizosphere of up to 11 herbaceous plant species, or to study their responses to the separate volatiles from whole plant swards or their root balls whose emanations had been collected in 1.5-l plastic bags fixed to the glass vessels. Excess CO2 was controlled with NaOH solution. Volatiles from root balls of parsley and pea but not wheat, from unplanted soils, from the fungus-permeated, unplanted substrate soil itself, and from the rooting soil of whole wheat sward increased mycelial densities in Clitocybe sp. more than in Agaricus macrocarpus and indicated thus a higher nutrient state of the mycelia. Organic volatiles proved therefore to be a significant carbon source for certain basidiomycetes in poor natural soils. The contemporary decline in the number of basidiocarp initials to 0 to 36% in both fungi relative to the unplanted and aerated controls was caused by volatiles from rooted and unplanted soil and pointed thus to their ecological role as antibiotics, fumigants, toxins, and hormonal compounds. Aqueous extracts from root balls of wheat stimulated mycelial density and fruiting in A. macrocarpus contemporarily because of their contents in soil-derived macronutrients. They suppressed once more fruiting in the more sensitive Clitocybe sp. by active agents in the aqueous phase. Within plant rhizospheres, densities of Clitocybe sp. mycelia were stimulated in the presence of alfalfa, carrot, red clover, ryegrass, and spinach, whereas those of A. macrocarpus were halved by 7 of 10 plant species including alfalfa, red clover, ryegrass, and spinach. Mycelia of A. macrocarpus may thereby have responded to differences in concentration and composition of volatile compounds. The contemporary repression of fruiting in both fungi and in nearly all treatments was not due to plant competition for macronutrients. Mycelia of basidiomycetes over-compensated for losses in macronutrients to the plant by decomposing soil matrix constituents. It is concluded that organic volatiles emitted by several plant organs and natural soils improved the nutritional state of A. macrocarpus and Clitocybe sp. but not of Agaricus bisporus mycelia and could therefore help establish certain ground fungi in the field. The contemporary and general suppression of fruiting by constituents of the gaseous (and liquid) phase in all fungi examined suggests interference with basic physiological processes and recommends an urgent re-examination of the degradative ability of basidiomycetes in the presence of volatiles.
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Affiliation(s)
- Gerhard Gramss
- Friedrich-Schiller-University of Jena, Institute of Nutritional Sciences, Dornburger Strasse 25, 07743 Jena, Germany.
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38
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Cleveland TE, Yu J, Bhatnagar D, Chen Z, Brown RL, Chang P, Cary JW. Progress in Elucidating the Molecular Basis of the Host Plant—AspergillusFlavusInteraction, a Basis for Devising Strategies to Reduce Aflatoxin Contamination in Crops. ACTA ACUST UNITED AC 2008. [DOI: 10.1081/txr-200027892] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Leitner M, Kaiser R, Rasmussen MO, Driguez H, Boland W, Mithöfer A. Microbial oligosaccharides differentially induce volatiles and signalling components in Medicago truncatula. PHYTOCHEMISTRY 2008; 69:2029-40. [PMID: 18534640 DOI: 10.1016/j.phytochem.2008.04.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 04/18/2008] [Accepted: 04/21/2008] [Indexed: 05/08/2023]
Abstract
Plants perceive biotic stimuli by recognising a multitude of different signalling compounds originating from the interacting organisms. Some of these substances represent pathogen-associated molecular patterns, which act as general elicitors of defence reactions. But also beneficial microorganisms like rhizobia take advantage of compounds structurally related to certain elicitors, i.e. Nod-factors, to communicate their presence to the host plant. In a bioassay-based study we aimed to determine to what extent distinct oligosaccharidic signals are able to elicit overlapping responses, including the emission of volatile organic compounds which is mainly considered a typical mode of inducible indirect defence against herbivores. The model legume Medicago truncatula Gaertn. was challenged with pathogen elicitors (beta-(1,3)-beta-(1,6)-glucans and N,N',N'',N'''-tetraacetylchitotetraose) and two Nod-factors, with one of them being able to induce a nodulation response in M. truncatula. Single oligosaccharidic elicitors caused the emission of volatile organic compounds, mainly sesquiterpenoids. The volatile blends detected were quite characteristic for the applied compounds, which could be pinpointed by multivariate statistical methods. As potential mediators of this response, the levels of jasmonic acid and salicylic acid were determined. Strikingly, neither of these phytohormones exhibited changing levels correlating with enhanced volatile emission. All stimuli tested caused an overproduction of reactive oxygen species, whereas nitric oxide accumulation was only effected by elicitors that were equally able to induce volatile emission. Thus, all signalling compounds tested elicited distinct reaction patterns. However, similarities between defence reactions induced by herbivory and pathogen-derived elicitors could be ascertained; but also Nod-factors were able to trigger defence-related reactions.
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Affiliation(s)
- Margit Leitner
- Max Planck Institute for Chemical Ecology, Department Bioorganic Chemistry, Jena, Germany
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40
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Holmes RA, Boston RS, Payne GA. Diverse inhibitors of aflatoxin biosynthesis. Appl Microbiol Biotechnol 2008; 78:559-72. [DOI: 10.1007/s00253-008-1362-0] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2007] [Revised: 01/09/2008] [Accepted: 01/10/2008] [Indexed: 10/22/2022]
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Roze LV, Beaudry RM, Arthur AE, Calvo AM, Linz JE. Aspergillus volatiles regulate aflatoxin synthesis and asexual sporulation in Aspergillus parasiticus. Appl Environ Microbiol 2007; 73:7268-76. [PMID: 17890344 PMCID: PMC2168228 DOI: 10.1128/aem.00801-07] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aspergillus parasiticus is one primary source of aflatoxin contamination in economically important crops. To prevent the potential health and economic impacts of aflatoxin contamination, our goal is to develop practical strategies to reduce aflatoxin synthesis on susceptible crops. One focus is to identify biological and environmental factors that regulate aflatoxin synthesis and to manipulate these factors to control aflatoxin biosynthesis in the field or during crop storage. In the current study, we analyzed the effects of aspergillus volatiles on growth, development, aflatoxin biosynthesis, and promoter activity in the filamentous fungus A. parasiticus. When colonies of Aspergillus nidulans and A. parasiticus were incubated in the same growth chamber, we observed a significant reduction in aflatoxin synthesis and asexual sporulation by A. parasiticus. Analysis of the headspace gases demonstrated that A. nidulans produced much larger quantities of 2-buten-1-ol (CA) and 2-ethyl-1-hexanol (EH) than A. parasiticus. In its pure form, EH inhibited growth and increased aflatoxin accumulation in A. parasiticus at all doses tested; EH also stimulated aflatoxin transcript accumulation. In contrast, CA exerted dose-dependent up-regulatory or down-regulatory effects on aflatoxin accumulation, conidiation, and aflatoxin transcript accumulation. Experiments with reporter strains carrying nor-1 promoter deletions and mutations suggested that the differential effects of CA were mediated through separate regulatory regions in the nor-1 promoter. The potential efficacy of CA as a tool for analysis of transcriptional regulation of aflatoxin biosynthesis is discussed. We also identify a novel, rapid, and reliable method to assess norsolorinic acid accumulation in solid culture using a Chroma Meter CR-300 apparatus.
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Affiliation(s)
- Ludmila V Roze
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824, USA
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42
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Tsitsigiannis DI, Keller NP. Oxylipins as developmental and host-fungal communication signals. Trends Microbiol 2007; 15:109-18. [PMID: 17276068 DOI: 10.1016/j.tim.2007.01.005] [Citation(s) in RCA: 219] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Revised: 01/04/2007] [Accepted: 01/23/2007] [Indexed: 12/30/2022]
Abstract
Pathogenic microbes and their hosts have acquired complex signalling mechanisms to appraise themselves of the environmental milieu in the ongoing battle for survival. Several recent studies have implicated oxylipins as a novel class of host-microbe signalling molecules. Oxylipins represent a vast and diverse family of secondary metabolites that originate from the oxidation or further conversion of polyunsaturated fatty acids. Among the microbial oxylipins, the fungal oxylipins are best characterized and function as hormone-like signals that modulate the timing and balance between asexual and sexual spore development in addition to toxin production. Coupled with other studies that implicate a role for fungal oxylipins in pathogenesis by Aspergillus and Candida spp., these results suggest that host and microbial oxylipins might interfere with the metabolism, perception or signalling processes of each other.
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Affiliation(s)
- Dimitrios I Tsitsigiannis
- The Sainsbury Laboratory, John Innes Centre, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, UK.
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43
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Bhatnagar D, Cary JW, Ehrlich K, Yu J, Cleveland TE. Understanding the genetics of regulation of aflatoxin production and Aspergillus flavus development. Mycopathologia 2006; 162:155-66. [PMID: 16944283 DOI: 10.1007/s11046-006-0050-9] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aflatoxins are polyketide-derived, toxic, and carcinogenic secondary metabolites produced primarily by two fungal species, Aspergillus flavus and A. parasiticus, on crops such as corn, peanuts, cottonseed, and treenuts. Regulatory guidelines issued by the U.S. Food and Drug Administration (FDA) prevent sale of commodities if contamination by these toxins exceeds certain levels. The biosynthesis of these toxins has been extensively studied. About 15 stable precursors have been identified. The genes involved in encoding the proteins required for the oxidative and regulatory steps in the biosynthesis are clustered in a 70 kb portion of chromosome 3 in the A. flavus genome. With the characterization of the gene cluster, new insights into the cellular processes that govern the genes involved in aflatoxin biosynthesis have been revealed, but the signaling processes that turn on aflatoxin biosynthesis during fungal contamination of crops are still not well understood. New molecular technologies, such as gene microarray analyses, quantitative polymerase chain reaction (PCR), and chromatin immunoprecipitation are being used to understand how physiological stress, environmental and soil conditions, receptivity of the plant, and fungal virulence lead to episodic outbreaks of aflatoxin contamination in certain commercially important crops. With this fundamental understanding, we will be better able to design improved non-aflatoxigenic biocompetitive Aspergillus strains and develop inhibitors of aflatoxin production (native to affected crops or otherwise) amenable to agricultural application for enhancing host-resistance against fungal invasion or toxin production. Comparisons of aflatoxin-producing species with other fungal species that retain some of the genes required for aflatoxin formation is expected to provide insight into the evolution of the aflatoxin gene cluster, and its role in fungal physiology. Therefore, information on how and why the fungus makes the toxin will be valuable for developing an effective and lasting strategy for control of aflatoxin contamination.
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Affiliation(s)
- Deepak Bhatnagar
- Food and Feed Safety Research Unit, U.S.D.A., A.R.S., Southern Regional Research Center, New Orleans, LA 70124, USA.
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Tsitsigiannis DI, Kunze S, Willis DK, Feussner I, Keller NP. Aspergillus infection inhibits the expression of peanut 13S-HPODE-forming seed lipoxygenases. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2005; 18:1081-9. [PMID: 16255247 DOI: 10.1094/mpmi-18-1081] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Oxylipins recently have been implicated as signaling molecules for cross-kingdom communication in plant-pathogen interactions. Linoleic acid and its two plant lipoxygenase (LOX) oxylipin products 9- and 13-hydroperoxy fatty acids (9S- and 13S-HPODE) have been shown to have a significant effect on differentiation processes in the mycotoxigenic seed pathogens Aspergillus spp. Whereas both fatty acids promote sporulation, 9S-HPODE stimulates and 13S-HPODE inhibits mycotoxin production. Additionally, Aspergillus flavus infection of seed promotes linoleate 9-LOX expression and 9S-HPODE accumulation. Here, we describe the characterization of two peanut seed lipoxygenase alleles (PnLOX2 and PnLOX3) highly expressed in mature seed. PnLOX2 and PnLOX3 both are 13S-HPODE producers (linoleate 13-LOX) and, in contrast to previously characterized 9-LOX or mixed function LOX genes, are repressed between 5-fold and 250-fold over the course of A. flavus infection. The results of these studies suggest that 9S-HPODE and 13S-HPODE molecules act as putative susceptibility and resistance factors respectively, in Aspergillus seed-aflatoxin interactions.
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Kishimoto K, Matsui K, Ozawa R, Takabayashi J. Volatile C6-aldehydes and Allo-ocimene activate defense genes and induce resistance against Botrytis cinerea in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2005; 46:1093-102. [PMID: 15879447 DOI: 10.1093/pcp/pci122] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Green leafy volatiles or isoprenoids are produced after mechanical wounding or pathogen/herbivore attacks in higher plants. We monitored expression profiles of the genes involved in defense responses upon exposing Arabidopsis thaliana to the volatiles. Among the genes investigated, those known to be induced by mechanical wounding and/or jasmonate application, such as chalcone synthase (CHS), caffeic acid-O-methyltransferase (COMT), diacylglycerol kinase1 (DGK1), glutathione-S-transferase1 (GST1) and lipoxygenase2 (LOX2), were shown to be induced with (E)-2-hexenal, (Z)-3-hexenal, (Z)-3-hexenol or allo-ocimene (2,6-dimethyl-2,4,6-octatriene). A salicylic acid-responsive gene, pathogenesis-related protein2 (PR2), was not induced by the volatiles. Detailed analyses of the expression profiles showed that the manner of induction varied depending on either the gene monitored or the volatile used. A chemically inert compound, (Z)-3-hexenol, was also potent, which suggested that chemical reactivity was not the sole requisite for the inducing activity. With a jasmonate-insensitive mutant (jar1), the induction by the volatiles was mostly suppressed, however, that of LOX2 was unaltered. An ethylene-insensitive mutant (etr1) showed responses almost identical to the wild type, with minor exceptions. From these observations, it was suggested that both the jasmonate-dependent and -independent pathways were operative upon perception of the volatiles, while the ETR1-dependent pathway was not directly involved. When Botrytis cinerea was inoculated after the volatile treatment, retardation of disease development could be seen. It appears that volatile treatment could make the plants more resistant against the fungal disease.
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Affiliation(s)
- Kyutaro Kishimoto
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Corporation, Kawaguchi, Saitama, 332-0012 Japan
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Santino A, Poltronieri P, Mita G. Advances on plant products with potential to control toxigenic fungi: A review. ACTA ACUST UNITED AC 2005; 22:389-95. [PMID: 16019809 DOI: 10.1080/02652030500058429] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In recent years, public pressure to reduce the use of synthetic fungicides in agriculture has increased. Concerns have been raised about both the environmental impact and the potential health risk related to the use of these compounds. Therefore, considerable efforts have been made towards the development of alternative crop protectants. The European Commission has been actively encouraging the development and commercial implementation of new compounds known as 'green chemicals'. In this context, an increase in the knowledge of plant defence responses to toxigenic fungi, which is covered in this review, will help to discover new plant products with antifungal activity and to design new strategies to improve plant resistance to these pathogens.
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Affiliation(s)
- A Santino
- Institute of Sciences of Food Production, National Research Council, Lecce, Italy.
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Roze LV, Calvo AM, Gunterus A, Beaudry R, Kall M, Linz JE. Ethylene modulates development and toxin biosynthesis in aspergillus possibly via an ethylene sensor-mediated signaling pathway. J Food Prot 2004; 67:438-47. [PMID: 15035355 DOI: 10.4315/0362-028x-67.3.438] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ethylene, a biologically active natural compound, inhibited aflatoxin accumulation by Aspergillus parasiticus on a solid growth medium in a dose-dependent manner at concentrations of 0.1 to 150 ppm. The activity of the nor-1 promoter (an early aflatoxin gene) was reduced to nondetectable levels by similar quantities of ethylene, suggesting that the inhibitory effect on toxin synthesis occurred, at least in part, at the level of transcription. The inhibitory effect of ethylene on aflatoxin accumulation was also observed when A. parasiticus was grown on raw peanuts. Under similar growth conditions and doses, ethylene strongly inhibited development of asci and ascospores in Aspergillus nidulans, with no detectable effect on Hülle cell formation, conidiation, or sterigmatocystin accumulation. During early growth, A. parasiticus and A. nidulans produced ethylene with approximately twofold higher quantities measured in continuous light than in the dark. 1-Methylcyclopropene (an inhibitor of ethylene receptors in plants), light, CO2, temperature, and growth medium composition altered the effect of ethylene on A. nidulans and A. parasiticus. These observations are consistent with the existence of an ethylene sensor molecule that mediates the function of an ethylene-responsive signaling pathway(s) in Aspergillus.
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Affiliation(s)
- L V Roze
- Department of Food Science and Human Nutrition, Michigan State University, Lansing, Michigan, USA
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Wilkinson J, Rood D, Minior D, Guillard K, Darre M, Silbart LK. Immune response to a mucosally administered aflatoxin B1 vaccine. Poult Sci 2003; 82:1565-72. [PMID: 14601734 DOI: 10.1093/ps/82.10.1565] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In the present study, a mucosal vaccine was used in an effort to elicit serum IgG and intestinal secretory IgA against the mycotoxin aflatoxin B1 (AFB) in chickens. AFB was coupled to carrier proteins (BSA and porcine thyroglobulin) for use as a vaccine and ELISA coating antigen, respectively. Seven-day-old broiler chicks were divided into groups of 10 and immunized with one of four vaccine preparations: 1) AFB-BSA conjugate alone, 2) AFB-BSA linked to the B subunit of the recombinant heat-labile enterotoxin of Escherichia coli (rLT-B), 3) AFB-BSA admixed with rLT-B, or 4) AFB-BSA mixed with cholera toxin (CT). Each vaccine preparation was administered perorally, intrarectally, or intraperitoneally, with a booster immunization given 2 wk later. Sera and feces were collected weekly and assayed using isotype specific ELISA. All three routes of immunization elicited significant serum IgG responses; however, the intraperitoneal route was strongest for all vaccine preparations tested. The serum IgG immune response to the AFB-BSA conjugate was enhanced by co-administration of rLT-B but not by covalent coupling to rLT-B or coadministration with CT. Secretory IgA anti-CT and anti-rLT-B antibodies were detected in fecal supernatants, but no anti-AFB responses could be detected. As all 12 treatment groups produced significant levels of serum IgG anti-AFB, any of these approaches, including oral administration without adjuvant, may afford the chicken some level of protection through simple immuno-interception of free AFB.
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Affiliation(s)
- J Wilkinson
- Department of Animal Science, University of Connecticut, Storrs, Connecticut 06269, USA
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Calvo AM, Wilson RA, Bok JW, Keller NP. Relationship between secondary metabolism and fungal development. Microbiol Mol Biol Rev 2002; 66:447-59, table of contents. [PMID: 12208999 PMCID: PMC120793 DOI: 10.1128/mmbr.66.3.447-459.2002] [Citation(s) in RCA: 652] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Filamentous fungi are unique organisms-rivaled only by actinomycetes and plants-in producing a wide range of natural products called secondary metabolites. These compounds are very diverse in structure and perform functions that are not always known. However, most secondary metabolites are produced after the fungus has completed its initial growth phase and is beginning a stage of development represented by the formation of spores. In this review, we describe secondary metabolites produced by fungi that act as sporogenic factors to influence fungal development, are required for spore viability, or are produced at a time in the life cycle that coincides with development. We describe environmental and genetic factors that can influence the production of secondary metabolites. In the case of the filamentous fungus Aspergillus nidulans, we review the only described work that genetically links the sporulation of this fungus to the production of the mycotoxin sterigmatocystin through a shared G-protein signaling pathway.
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Affiliation(s)
- Ana M Calvo
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois 60115, USA
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Gardini F, Lanciotti R, Guerzoni ME. Effect of trans-2-hexenal on the growth of Aspergillus flavus in relation to its concentration, temperature and water activity. Lett Appl Microbiol 2001; 33:50-5. [PMID: 11442815 DOI: 10.1046/j.1472-765x.2001.00956.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS The antifungal activity of trans-2-hexenal on Aspergillus flavus in a model system in relation to its concentration, incubation temperature and aw was assessed. METHODS AND RESULTS A model describing the antifungal activity of the aldehyde in relation to these variables was obtained. CONCLUSION According to this model, the inhibition of A. flavus was weakly dependent on the incubation temperature (at least within the range of values considered) and strongly affected by the trans-2-hexenal concentration and aw, which showed a remarkable synergistic effect. SIGNIFICANCE AND IMPACT OF THE STUDY Trans-2-hexenal proved to be a molecule with remarkable antimicrobial properties, even when added in closed systems at low concentration.
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Affiliation(s)
- F Gardini
- Dipartimento di Protezione e Valorizzazione Agroalimentare, Università degli Studi di Bologna, Bologna, Italy.
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