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Zarrin M, Shialy Z. Molecular analysis of acid-stable alpha-amylase (asAA) gene in Aspergillus niger using PCR-RFLP. Biomedicine (Taipei) 2022. [DOI: 10.51248/.v42i5.1726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Introduction and Aim: Amylase is an important enzyme with vast applications in various industries such as food and therapeutic industries. Aspergillus niger is commercially engaged in the making of alpha-amylase. Acid-stable alpha -amylase is mostly produced with microorganisms such as Bacillus and Aspergillus. The aim of this research was the molecular investigation of the acid-stable alpha-amylase (alpha-sAA) gene in A. niger.
Materials and Methods: Sixty-three A. niger isolates were evaluated in this study. PCR method was performed for amplification of a 347 bp DNA band of the alpha-sAA gene. The Hpa II Restriction endonuclease was used for the digestion of PCR fragments.
Results: A 347 bp DNA fragment was recovered from 49 out of 63 (78%) isolates. After cutting the PCR products with the HpalphaII enzyme, 81.6% of isolates showed the expected band and 18.4% presented different restriction endonuclease patterns.
Conclusion: The results demonstrated the PCR-RFLP technique performed in this research was a valuable tool for analysis of the alpha-sAA gene in A. niger isolates.
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Han JW, Kim DY, Lee YJ, Choi YR, Kim B, Choi GJ, Han SW, Kim H. Transcription Factor PdeR Is Involved in Fungal Development, Metabolic Change, and Pathogenesis of Gray Mold Botrytis cinerea. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:9171-9179. [PMID: 32786857 DOI: 10.1021/acs.jafc.0c02420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The necrotrophic fungus Botrytis cinerea releases extracellular enzymes that facilitate its penetration into a host. This study functionally characterized the gene pdeR of B. cinerea, which is predicted to encode a Zn(II)2Cys6 zinc finger transcription factor. To investigate the role of pdeR, deleted and complemented strains of pdeR in B. cinerea were generated, which were designated as ΔpdeR and PdeRc, respectively. The ΔpdeR strain exhibited impaired germination and growth compared to the wild-type and PdeRc strains, particularly when provided with maltose as the sole carbon source. When all of the strains were grown on a minimal medium containing polysaccharide as the sole carbon source, the ΔpdeR exclusively showed defects in polysaccharide hydrolysis with reduced gene expression encoding for amylase and cellulase. As far as the involvement of pdeR in carbon metabolism is concerned, metabolic changes were investigated in the ΔpdeR mutant. Comparisons of relative, normalized concentrations of each metabolite showed that the amounts of six metabolites including glucose and trehalose were significantly changed in the ΔpdeR strain. Based on pleiotropic changes derived from the deletion of pdeR, we hypothesized that pdeR has an important role in pathogenesis. When the ΔpdeR strain was inoculated onto pepper plant, the ΔpdeR strain did not cause expansion of the disease lesions from the infection sites, which grew on the surface without any penetration. Taken together, these results show that the deletion of pdeR affected the extracellular enzymatic activity, leading to changes in fungal development, metabolism, and virulence.
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Affiliation(s)
- Jae Woo Han
- Center for Eco-Friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea
| | - Da Yeon Kim
- Center for Eco-Friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea
| | - Yu Jeong Lee
- Center for Eco-Friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea
- Department of Medicinal Chemistry and Pharmacology, University of Science and Technology, Daejeon 34113, Korea
| | - Yee Ram Choi
- Center for Eco-Friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea
| | - Bomin Kim
- Center for Eco-Friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea
- Department of Medicinal Chemistry and Pharmacology, University of Science and Technology, Daejeon 34113, Korea
| | - Gyung Ja Choi
- Center for Eco-Friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea
- Department of Medicinal Chemistry and Pharmacology, University of Science and Technology, Daejeon 34113, Korea
| | - Sang-Wook Han
- Department of Plant Science and Technology, Chung-Ang University, Anseong 17546, Korea
| | - Hun Kim
- Center for Eco-Friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea
- Department of Medicinal Chemistry and Pharmacology, University of Science and Technology, Daejeon 34113, Korea
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Shanmugavel M, Nivedha lakshmi J, Vasantharaj S, Anu C, Paul LE, Kumar RP, Gnanamani A. Wealth from waste: Recovery of the commercially important waxy ester from enzymatic dehaired sheep wool. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2019. [DOI: 10.1016/j.bcab.2019.101255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Pandey V, Gupta AK, Singh M, Pandey D, Kumar A. Complementary Proteomics, Genomics approaches identifies potential pathogenicity/virulence factors in Tilletia indica induced under the influence of host factor. Sci Rep 2019; 9:553. [PMID: 30679765 PMCID: PMC6346058 DOI: 10.1038/s41598-018-37810-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 12/05/2018] [Indexed: 12/21/2022] Open
Abstract
Karnal bunt disease of wheat is incited by quarantine fungal pathogen T. indica. Till date, there is little information on the pathogenic mechanisms involved in Karnal bunt. In order to understand the molecular mechanisms of disease pathogenesis, highly aggressive T. indica TiK isolate was cultured in the presence of host factor extracted from developing spikes of wheat variety WH-542. Modulation in protein profile of mycelial proteins and secretome from TiK cultured in the absence and presence of host factor was analyzed by 2-DE. Fifteen and twenty nine protein spots were up-regulated/differentially regulated in the proteome of mycelial and secreted proteins, respectively and identified using MALDI-TOF/TOF. Identified proteins are involved in suppression of host defense responses, lignin degradation of plant cell wall, penetration, adhesion of pathogen to host tissues, pathogen mediated reactive oxygen species generation, hydrolytic enzymes, detoxification of host generated reactive oxygen species. Further, integration of proteomic and genomic analysis has led to candidate pathogenicity/virulence factors identification. They were functionally annotated by sequence as well as structure based analysis. In this study, complementation of proteomics and genomics approaches resulted in novel pathogenicity/virulence factor(s) identification in T. indica.
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Affiliation(s)
- Vishakha Pandey
- Department of Molecular biology and Genetic Engineering, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India
| | - Atul Kumar Gupta
- Department of Molecular biology and Genetic Engineering, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India.
| | - Manoj Singh
- Department of Molecular biology and Genetic Engineering, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India
| | - Dinesh Pandey
- Department of Molecular biology and Genetic Engineering, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India
| | - Anil Kumar
- Department of Molecular biology and Genetic Engineering, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India.
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Fountain JC, Koh J, Yang L, Pandey MK, Nayak SN, Bajaj P, Zhuang WJ, Chen ZY, Kemerait RC, Lee RD, Chen S, Varshney RK, Guo B. Proteome analysis of Aspergillus flavus isolate-specific responses to oxidative stress in relationship to aflatoxin production capability. Sci Rep 2018; 8:3430. [PMID: 29467403 PMCID: PMC5821837 DOI: 10.1038/s41598-018-21653-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 02/03/2018] [Indexed: 12/24/2022] Open
Abstract
Aspergillus flavus is an opportunistic pathogen of plants such as maize and peanut under conducive conditions such as drought stress resulting in significant aflatoxin production. Drought-associated oxidative stress also exacerbates aflatoxin production by A. flavus. The objectives of this study were to use proteomics to provide insights into the pathogen responses to H2O2-derived oxidative stress, and to identify potential biomarkers and targets for host resistance breeding. Three isolates, AF13, NRRL3357, and K54A with high, moderate, and no aflatoxin production, were cultured in medium supplemented with varying levels of H2O2, and examined using an iTRAQ (Isobaric Tags for Relative and Absolute Quantification) approach. Overall, 1,173 proteins were identified and 220 were differentially expressed (DEPs). Observed DEPs encompassed metabolic pathways including antioxidants, carbohydrates, pathogenicity, and secondary metabolism. Increased lytic enzyme, secondary metabolite, and developmental pathway expression in AF13 was correlated with oxidative stress tolerance, likely assisting in plant infection and microbial competition. Elevated expression of energy and cellular component production in NRRL3357 and K54A implies a focus on oxidative damage remediation. These trends explain isolate-to-isolate variation in oxidative stress tolerance and provide insights into mechanisms relevant to host plant interactions under drought stress allowing for more targeted efforts in host resistance research.
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Affiliation(s)
- Jake C Fountain
- Department of Plant Pathology, University of Georgia, Tifton, GA, USA.,USDA-ARS Crop Protection and Management Research Unit, Tifton, GA, USA.,Center of Excellence in Genomics & Systems Biology, International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Telangana, India
| | - Jin Koh
- Department of Biology, Genetics Institute, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL, USA
| | - Liming Yang
- Department of Plant Pathology, University of Georgia, Tifton, GA, USA.,USDA-ARS Crop Protection and Management Research Unit, Tifton, GA, USA.,College of Biology and Environmental Science, Nanjing Forestry University, Nanjing, China
| | - Manish K Pandey
- Center of Excellence in Genomics & Systems Biology, International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Telangana, India
| | - Spurthi N Nayak
- Center of Excellence in Genomics & Systems Biology, International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Telangana, India
| | - Prasad Bajaj
- Center of Excellence in Genomics & Systems Biology, International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Telangana, India
| | - Wei-Jian Zhuang
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Zhi-Yuan Chen
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA, USA
| | - Robert C Kemerait
- Department of Plant Pathology, University of Georgia, Tifton, GA, USA
| | - R Dewey Lee
- Department of Crop and Soil Sciences, University of Georgia, Tifton, GA, USA
| | - Sixue Chen
- Department of Biology, Genetics Institute, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL, USA
| | - Rajeev K Varshney
- Center of Excellence in Genomics & Systems Biology, International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Telangana, India
| | - Baozhu Guo
- USDA-ARS Crop Protection and Management Research Unit, Tifton, GA, USA.
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Cryptococcus strains with different pathogenic potentials have diverse protein secretomes. EUKARYOTIC CELL 2015; 14:554-63. [PMID: 25841021 DOI: 10.1128/ec.00052-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 03/30/2015] [Indexed: 12/25/2022]
Abstract
Secreted proteins are the frontline between the host and pathogen. In mammalian hosts, secreted proteins enable invasive infection and can modulate the host immune response. Cryptococcosis, caused by pathogenic Cryptococcus species, begins when inhaled infectious propagules establish to produce pulmonary infection, which, if not resolved, can disseminate to the central nervous system to cause meningoencephalitis. Strains of Cryptococcus species differ in their capacity to cause disease, and the mechanisms underlying this are not well understood. To investigate the role of secreted proteins in disease, we determined the secretome for three genome strains of Cryptococcus species, including a hypovirulent and a hypervirulent strain of C. gattii and a virulent strain of C. neoformans. Sixty-seven unique proteins were identified, with different numbers and types of proteins secreted by each strain. The secretomes of the virulent strains were largely limited to proteolytic and hydrolytic enzymes, while the hypovirulent strain had a diverse secretome, including non-conventionally secreted canonical cytosolic and immunogenic proteins that have been implicated in virulence. The hypovirulent strain cannot establish pulmonary infection in a mouse model, but strains of this genotype have caused human meningitis. To directly test brain infection, we used intracranial inoculation and found that the hypovirulent strain was substantially more invasive than its hypervirulent counterpart. We suggest that immunogenic proteins secreted by this strain invoke a host response that limits pulmonary infection but that there can be invasive growth and damage if infection reaches the brain. Given their known role in virulence, it is possible that non-conventionally secreted proteins mediate this process.
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Fountain JC, Scully BT, Ni X, Kemerait RC, Lee RD, Chen ZY, Guo B. Environmental influences on maize-Aspergillus flavus interactions and aflatoxin production. Front Microbiol 2014; 5:40. [PMID: 24550905 PMCID: PMC3913990 DOI: 10.3389/fmicb.2014.00040] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 01/21/2014] [Indexed: 12/25/2022] Open
Abstract
Since the early 1960s, the fungal pathogen Aspergillus flavus (Link ex Fr.) has been the focus of intensive research due to the production of carcinogenic and highly toxic secondary metabolites collectively known as aflatoxins following pre-harvest colonization of crops. Given this recurrent problem and the occurrence of a severe aflatoxin outbreak in maize (Zea mays L.), particularly in the Southeast U.S. in the 1977 growing season, a significant research effort has been put forth to determine the nature of the interaction occurring between aflatoxin production, A. flavus, environment and its various hosts before harvest. Many studies have investigated this interaction at the genetic, transcript, and protein levels, and in terms of fungal biology at either pre- or post-harvest time points. Later experiments have indicated that the interaction and overall resistance phenotype of the host is a quantitative trait with a relatively low heritability. In addition, a high degree of environmental interaction has been noted, particularly with sources of abiotic stress for either the host or the fungus such as drought or heat stresses. Here, we review the history of research into this complex interaction and propose future directions for elucidating the relationship between resistance and susceptibility to A. flavus colonization, abiotic stress, and its relationship to oxidative stress in which aflatoxin production may function as a form of antioxidant protection to the producing fungus.
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Affiliation(s)
- Jake C. Fountain
- Department of Plant Pathology, University of GeorgiaTifton, GA, USA
| | - Brian T. Scully
- Crop Protection and Management Research Unit, Agricultural Research Service – United States Department of AgricultureTifton, GA, USA
| | - Xinzhi Ni
- Crop Genetics and Breeding Research Unit, Agricultural Research Service – United States Department of AgricultureTifton, GA, USA
| | | | - Robert D. Lee
- Department of Crop and Soil Sciences, University of GeorgiaTifton, GA, USA
| | - Zhi-Yuan Chen
- Department of Plant Pathology and Crop Physiology, Louisiana State UniversityBaton Rouge, LA, USA
| | - Baozhu Guo
- Department of Plant Pathology, University of GeorgiaTifton, GA, USA
- Crop Protection and Management Research Unit, Agricultural Research Service – United States Department of AgricultureTifton, GA, USA
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Geethu C, Resna AK, Nair RA. Characterization of major hydrolytic enzymes secreted by Pythium myriotylum, causative agent for soft rot disease. Antonie Van Leeuwenhoek 2013; 104:749-57. [PMID: 23897210 DOI: 10.1007/s10482-013-9983-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 07/22/2013] [Indexed: 12/22/2022]
Abstract
Pythium myriotylum, an oomycetous necrotroph is the causal agent of soft rot disease affecting several crops. Successful colonization by necrotrophs depends on their secretion of a diverse array of plant cell wall degrading enzymes (CWDEs). The induction dynamics of CWDEs secreted by P. myriotylum was analysed as little information is available for this pathogen. Activities of CWDEs that included pectinase, cellulase, xylanase and protease were detected using radial diffusion assay and differential staining. In Czapek Dox minimal medium supplemented with respective substrates as carbon source, the increase in CWDE activities was observed till 8 days of incubation after which a gradual decline in enzymatic activities was observed. With sucrose as sole carbon source, all the enzymes studied showed increase in activity with fungal growth while with cell wall material derived from ginger rhizome as sole carbon source, an initial spurt in cellulase, xylanase and pectinase activities was observed 3 days post incubation while protease activity increased from three days of incubation and reached maximum at 13 days of incubation. To further evaluate the role of CWDEs in pathogenicity, UV-induced mutants (pmN14uv1) were generated wherein significant reduction in cellulase, pectinase and protease activities were observed while that of xylanase remained unchanged compared to wild type isolate (RGCBN14). Bioassays indicated changes in infection potential of pmN14uv1 thereby suggesting the crucial role played by P. myriotylum CWDEs in initiating the rotting process. Hence appropriate strategies that target the production/activity of these secretory hydrolytic enzymes will help in reducing disease incidence/pathogen virulence.
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Affiliation(s)
- C Geethu
- School of Biotechnology, National Institute of Technology Calicut (NITC), Calicut, Kerala, India
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Cotty PJ, Mellon JE. Ecology of aflatoxin producing fungi and biocontrol of aflatoxin contamination. Mycotoxin Res 2013; 22:110-7. [PMID: 23605583 DOI: 10.1007/bf02956774] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Aflatoxins, highly toxic and carcinogenic compounds that frequently contaminate foods and feeds, are produced by several genera in the genusAspergillus. Aspergillus flavus, the most common species causing crop contamination, is a common inhabitant of the Sonoran desert of North America where it resides in complex communities composed of diverse individuals. This diversity reflects divergent adaptation to various ecological niches. SomeA. flavus isolates that are well adapted to plant associated niches do not produce aflatoxins yet have the capacity to competitively exclude aflatoxin producers. These atoxigenic strains can serve as biological control agents for management of aflatoxins in crops. Detailed knowledge of the ecology of aflatoxin-producing fungi may lead to novel practical methods for limiting contamination.
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Affiliation(s)
- P J Cotty
- Agricultural Research Service, United States Department of Agriculture and Division of Plant Pathology and Microbiology, Department of Plant Sciences, University of Arizona, 85721, Tucson, AZ, USA,
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Abstract
Aspergillus flavus is saprophytic soil fungus that infects and contaminates preharvest and postharvest seed crops with the carcinogenic secondary metabolite aflatoxin. The fungus is also an opportunistic animal and human pathogen causing aspergillosis diseases with incidence increasing in the immunocompromised population. Whole genome sequences of A. flavus have been released and reveal 55 secondary metabolite clusters that are regulated by different environmental regimes and the global secondary metabolite regulators LaeA and VeA. Characteristics of A. flavus associated with pathogenicity and niche specialization include secondary metabolite production, enzyme elaboration, and a sophisticated oxylipin host crosstalk associated with a quorum-like development program. One of the more promising strategies in field control involves the use of atoxic strains of A. flavus in competitive exclusion studies. In this review, we discuss A. flavus as an agricultural and medical threat and summarize recent research advances in genomics, elucidation of parameters of pathogenicity, and control measures.
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Affiliation(s)
- Saori Amaike
- Department of Plant Pathology, University of Wisconsin, Madison, Wisconsin 53706, USA
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Luo M, Brown RL, Chen ZY, Cleveland TE. Host genes involved in the interaction betweenAspergillus flavusand maize. TOXIN REV 2009. [DOI: 10.1080/15569540903089197] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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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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13
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Eun JS, Beauchemin K. Relationship between enzymic activities and in vitro degradation of alfalfa hay and corn silage. Anim Feed Sci Technol 2008. [DOI: 10.1016/j.anifeedsci.2007.05.039] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Brotman Y, Briff E, Viterbo A, Chet I. Role of swollenin, an expansin-like protein from Trichoderma, in plant root colonization. PLANT PHYSIOLOGY 2008; 147:779-89. [PMID: 18400936 PMCID: PMC2409044 DOI: 10.1104/pp.108.116293] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Swollenin, a protein first characterized in the saprophytic fungus Trichoderma reesei, contains an N-terminal carbohydrate-binding module family 1 domain (CBD) with cellulose-binding function and a C-terminal expansin-like domain. This protein was identified by liquid chromatography-mass spectrometry among many other cellulolytic proteins secreted in the coculture hydroponics medium of cucumber (Cucumis sativus) seedlings and Trichoderma asperellum, a well-known biocontrol agent and inducer of plant defense responses. The swollenin gene was isolated and its coding region was overexpressed in the same strain under the control of the constitutive pki1 promoter. Trichoderma transformants showed a remarkably increased ability to colonize cucumber roots within 6 h after inoculation. On the other hand, overexpressors of a truncated swollenin sequence bearing a 36-amino acid deletion of the CBD did not differ from the wild type, showing in vivo that this domain is necessary for full protein activity. Root colonization rates were reduced in transformants silenced in swollenin gene expression. A synthetic 36-mer swollenin CBD peptide was shown to be capable of stimulating local defense responses in cucumber roots and leaves and to afford local protection toward Botrytis cinerea and Pseudomonas syringae pv lachrymans infection. This indicates that the CBD domain might be recognized by the plant as a microbe-associated molecular pattern in the Trichoderma-plant interaction.
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Affiliation(s)
- Yariv Brotman
- Department of Plant Pathology and Microbiology, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
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Aspergillus flavus hydrolases: their roles in pathogenesis and substrate utilization. Appl Microbiol Biotechnol 2007; 77:497-504. [DOI: 10.1007/s00253-007-1201-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 09/10/2007] [Accepted: 09/12/2007] [Indexed: 10/22/2022]
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Abstract
Fungi belonging to Aspergillus section Flavi are of great economic importance in the United States due to their ability to produce toxic and carcinogenic aflatoxins in agricultural commodities. Development of control strategies against A. flavus and A. parasiticus, the major aflatoxin-producing species, is dependent upon a basic understanding of their diversity in agricultural ecosystems. This review summarizes our current knowledge of species and population diversity in the United States in relation to morphology, mycotoxin production and genetic characters. The high genetic diversity in populations of aflatoxigenic fungi is a reflection of their versatile habits in nature, which include saprotrophic colonization of plant debris in soil and parasitism of seeds and grain. Genetic variation within populations may originate from a cryptic sexual state. The advent of intensive monoculture agriculture not only increases population size but also may introduce positive selective pressure for aflatoxin production due to its link with pathogenicity in crops. Important goals in population research are to determine how section Flavi diversity in agricultural ecosystems is changing and to measure the direction of this evolution.
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Affiliation(s)
- Bruce W Horn
- US Department of Agriculture, Agricultural Research Service, National Peanut Research Laboratory, PO Box 509, Dawson, GA 39842, USA.
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17
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Eun JS, Beauchemin K, Schulze H. Use of an in vitro fermentation bioassay to evaluate improvements in degradation of alfalfa hay due to exogenous feed enzymes. Anim Feed Sci Technol 2007. [DOI: 10.1016/j.anifeedsci.2006.07.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Kim YH, Woloshuk CP, Cho EH, Bae JM, Song YS, Huh GH. Cloning and functional expression of the gene encoding an inhibitor against Aspergillus flavus alpha-amylase, a novel seed lectin from Lablab purpureus (Dolichos lablab). PLANT CELL REPORTS 2007; 26:395-405. [PMID: 17149640 DOI: 10.1007/s00299-006-0250-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2006] [Revised: 09/14/2006] [Accepted: 09/17/2006] [Indexed: 05/12/2023]
Abstract
Maize is one of the more important agricultural crops in the world and, under certain conditions, prone to attack from pathogenic fungi. One of these, Aspergillus flavus, produces toxic and carcinogenic metabolites, called aflatoxins, as byproducts of its infection of maize kernels. The alpha-amylase of A. flavus is known to promote aflatoxin production in the endosperm of these infected kernels, and a 36-kDa protein from the Lablab purpureus, denoted AILP, has been shown to inhibit alpha-amylase production and the growth of A. flavus. Here, we report the isolation of six full-length labAI genes encoding AILP and a detailed analysis of the activities of the encoded proteins. Each of the six labAI genes encoded sequences of 274 amino acids, with the deduced amino acid sequences showing approximately 95-99% identity. The sequences are similar to those of lectin members of a legume lectin-arcelin-alpha-amylase inhibitor family reported to function in plant resistance to insect pests. The labAI genes did not show any of the structures characteristic of conserved structures identified in alpha-amylase inhibitors to date. The recombinant proteins of labAI-1 and labAI-2 agglutinated human red blood cells and inhibited A. flavus alpha-amylase in a manner similar to that shown by AILP. These data indicate that labAI genes are a new class of lectin members in legume seeds and that their proteins have both lectin and alpha-amylase inhibitor activity. These results are a valuable contribution to our knowledge of plant-pathogen interactions and will be applicable for developing protocols aimed at controlling A. flavus infection.
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Affiliation(s)
- Young-Hwa Kim
- School of Food and Life Science, BPRC, Inje University, Obangdong, 607, Gyungnam, Korea
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19
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Exogenous enzymes added to untreated or ammoniated rice straw: Effects on in vitro fermentation characteristics and degradability. Anim Feed Sci Technol 2006. [DOI: 10.1016/j.anifeedsci.2006.01.026] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Brodhagen M, Keller NP. Signalling pathways connecting mycotoxin production and sporulation. MOLECULAR PLANT PATHOLOGY 2006; 7:285-301. [PMID: 20507448 DOI: 10.1111/j.1364-3703.2006.00338.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
SUMMARY Mycotoxin contamination of food and feed presents a serious food safety issue on a global scale, causing tremendous yield and economic losses. These toxins, produced largely by members of the genera Aspergillus and Fusarium, represent a subset of the impressive array of secondary metabolites produced by filamentous fungi. Some secondary metabolites are associated temporally and functionally with sporulation. In Aspergillus and Fusarium, sporulation and mycotoxin production are both regulated by G protein signalling pathways. G protein signalling pathways commonly regulate fungal development, stress response and expression of virulence traits. In addition, fungal development is influenced by external factors. Among these are lipids, and in particular, oxylipin signals, which may be derived from either the fungus or infected seeds. Regardless of origin, oxylipins have the potential to elicit profound changes in both sporulation and mycotoxin production in the fungus. Signal transduction via G protein signalling pathways represents one mechanism by which oxylipin signals might elicit these changes. Therefore, in this review we integrate discussion of oxylipin signals and of G protein signalling cascades as regulators of fungal development.
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Affiliation(s)
- Marion Brodhagen
- Department of Plant Pathology, University of Wisconsin-Madison, 1630 Linden Dr, Madison, WI 53706-1598, USA
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Yu J, Cleveland TE, Nierman WC, Bennett JW. Aspergillus flavus genomics: gateway to human and animal health, food safety, and crop resistance to diseases. Rev Iberoam Micol 2006; 22:194-202. [PMID: 16499411 DOI: 10.1016/s1130-1406(05)70043-7] [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: 11/30/2022] Open
Abstract
Aspergillus flavus is an imperfect filamentous fungus that is an opportunistic pathogen causing invasive and non-invasive aspergillosis in humans, animals, and insects. It also causes allergic reactions in humans. A. flavus infects agricultural crops and stored grains and produces the most toxic and potent carcinogic metabolites such as aflatoxins and other mycotoxins. Breakthroughs in A. flavus genomics may lead to improvement in human health, food safety, and agricultural economy. The availability of A. flavus genomic data marks a new era in research for fungal biology, medical mycology, agricultural ecology, pathogenicity, mycotoxin biosynthesis, and evolution. The availability of whole genome microarrays has equipped scientists with a new powerful tool for studying gene expression under specific conditions. They can be used to identify genes responsible for mycotoxin biosynthesis and for fungal infection in humans, animals and plants. A. flavus genomics is expected to advance the development of therapeutic drugs and to provide information for devising strategies in controlling diseases of humans and other animals. Further, it will provide vital clues for engineering commercial crops resistant to fungal infection by incorporating antifungal genes that may prevent aflatoxin contamination of agricultural harvest.
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Affiliation(s)
- Jiujiang Yu
- USDA/ARS, Southern Regional Research Center, 1100 Robert E. Lee Boulevard, New Orleans, LA 70124, USA.
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Production of extracellular enzymes and aflatoxins in solid substrate fermentation with aflatoxigenicAspergillus spp. Mycotoxin Res 2004; 20:87-96. [DOI: 10.1007/bf02946739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Revised: 11/18/2004] [Indexed: 10/21/2022]
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Colombatto D, Morgavi DP, Furtado AF, Beauchemin KA. Screening of exogenous enzymes for ruminant diets: relationship between biochemical characteristics and in vitro ruminal degradation. J Anim Sci 2004; 81:2628-38. [PMID: 14552392 DOI: 10.2527/2003.81102628x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
With the objective of developing a rational approach for the selection of feed enzymes for ruminants, 22 commercial enzyme products were examined in terms of protein concentration, enzymic activities on model substrates, and hydrolytic capacity, the latter determined from the release of reducing sugars from alfalfa hay and corn silage. An in vitro ruminal degradation assessment was carried out using the same substrates, untreated or treated with the 22 enzyme products at 1.5 microL/g forage DM. Stepwise regressions were then performed to establish relationships between these factors. Protein concentration and enzymic activities explained at least 84% (P < 0.01) of the variation in the release of reducing sugars from alfalfa and corn silage. Alfalfa DM degradation after incubation with ruminal fluid for 18 h was positively related to xylanase activity (R2 = 0.29, P < 0.01), but the same activity was negatively related to DM degradation of corn silage (R2 = 0.19, P < 0.05). Protease activity explained a further 10% of the alfalfa DM degradation (P < 0.10). Following sequential steps involving the determination of rate and extent of DM and fiber degradation, the best candidates for alfalfa and corn silage were selected. Enzyme products effective with alfalfa hay seemed to exert part of their effect during the pretreatment period, whereas enzymes effective with corn silage worked exclusively after ruminal fluid was added. This finding suggests that different modes of action of exogenous enzymes are attacking different substrates and may partly explain enzyme-feed specificity. In alfalfa, it seems that effective enzymes work by removing structural barriers that retard the microbial colonization of digestible fractions, increasing the rate of degradation. In corn silage, effective enzymes seem to interact with ruminal enzymes to degrade the forage more rapidly, which is consistent with previous findings of synergism between exogenous and ruminal enzymes.
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Affiliation(s)
- D Colombatto
- Agriculture and Agri-Food Canada, Lethbridge, AB, Canada T1J 4B1.
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Krunic AL, Medenica M, Busbey S. Solitary embolic cutaneous aspergillosis in the immunocompromised patient with acute myelogenous leukemia - a propos another case caused by Aspergillus flavus. Int J Dermatol 2003; 42:946-50. [PMID: 14636189 DOI: 10.1111/j.1365-4632.2003.01807.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Martel MB, Hervé du Penhoat C, Létoublon R, Fèvre M. Purification and characterization of a glucoamylase secreted by the plant pathogen Scierotinia sclerotiorum. Can J Microbiol 2002; 48:212-8. [PMID: 11989765 DOI: 10.1139/w02-011] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Among the lytic enzymes secreted by the phytopathogen fungus Sclerotinia sclerotiorum, a starch-degrading enzyme has been isolated and characterized. This glycoprotein of 72 kDa is composed of several isoforms ranging from pI 4.8 to 5.4. The enzymatic parameters have been determined. Specificity studies together with the analysis of the reaction products show that it is an alpha-1,4-glucanohydrolase. This result is also corroborated by the analysis of the N-terminal and two inner amino acids sequences that are very similar to fungal glucoamylase genes or enzymes so far sequenced.
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Affiliation(s)
- M B Martel
- Laboratoire de biologie cellulaire fongique (UMR 5122) Université Lyon I Villeurbanne, France
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