Identification of a Halogenase Involved in the Biosynthesis of Ochratoxin A in Aspergillus carbonarius
| العنوان: | Identification of a Halogenase Involved in the Biosynthesis of Ochratoxin A in Aspergillus carbonarius |
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| المؤلفون: | Massimo Ferrara, Michele Solfrizzo, Giancarlo Perrone, Lucia Gambacorta, Antonia Gallo, Filomena Epifani |
| المصدر: | Applied and environmental microbiology 82 (2016): 5631–5641. doi:10.1128/AEM.01209-16 info:cnr-pdr/source/autori:Ferrara M.; Perrone G.; Gambacorta L.; Epifani F.; Solfrizzo M.; Gallo A./titolo:Identification of a Halogenase Involved in the Biosynthesis of Ochratoxin A in Aspergillus carbonarius/doi:10.1128%2FAEM.01209-16/rivista:Applied and environmental microbiology (Print)/anno:2016/pagina_da:5631/pagina_a:5641/intervallo_pagine:5631–5641/volume:82 |
| بيانات النشر: | American Society for Microbiology, 2016. |
| سنة النشر: | 2016 |
| مصطلحات موضوعية: | 0301 basic medicine, Ochratoxin A, biosynthetic cluster, Sequence analysis, 030106 microbiology, Aspergillus carbonarius, Biology, Applied Microbiology and Biotechnology, Mass Spectrometry, 03 medical and health sciences, chemistry.chemical_compound, Protein sequencing, Biosynthesis, Putative gene, Mycotoxin, Gene, Genetics, chemistry.chemical_classification, Ecology, gene deletion, chlorogenase, Ochratoxins, Biosynthetic Pathways, Aspergillus, 030104 developmental biology, Enzyme, chemistry, Biochemistry, Multigene Family, Food Microbiology, Oxidoreductases, Food Science, Biotechnology |
| الوصف: | Aspergillus carbonarius is the main responsible fungus of ochratoxin A (OTA) contamination of grapes and derived products. To date, the biosynthetic mechanism of this mycotoxin has been partially elucidated. Availability of genome sequence of A. carbonarius has allowed the identification of a putative gene cluster involved in OTA biosynthesis. This region hosts the previously characterized AcOTAnrps and AcOTApks genes encoding two key enzymes of the biosynthetic pathway. At about 4,400 nucleotides downstream of these loci, a gene encoding a putative flavin dependent-halogenase came out from the annotation data. Its proximity to OTA biosynthetic genes and its sequence analysis have suggested a role in the biosynthesis of OTA, directed to the introduction of the chlorine atom in the C-5 position of the final molecular structure of this mycotoxin. The deduced protein sequence of the halogenase gene, we designated AcOTAhal , shows a high similarity to a halogenase that is located in the OTA cluster of A. niger . The deletion of the halogenase gene completely eliminated the production of ochratoxin A in A. carbonarius and determined a significant increase of ochratoxin B, as confirmed by mass spectrometry analysis. Moreover, its expression profile was similar to the two biosynthetic genes previously identified, AcOTApks and AcOTAnrps , indicating a strong correlation of the AcOTAhal gene with the kinetics of OTA accumulation in A. carbonarius. Therefore, experimental evidence confirmed that the chlorination step which converts OTB in OTA represents the final stage of the biosynthetic pathway, supporting our earlier hypothesis on the order of enzymatic steps of OTA biosynthesis in A. carbonarius . IMPORTANCE Ochratoxin A is a potent mycotoxin classified as a possible carcinogen for humans, and Aspergillus carbonarius is the main agent responsible for OTA accumulation in grapes. We demonstrate here that a flavin-halogenase is implicated in the biosynthesis of OTA in A. carbonarius . The encoding gene, AcOTAhal , is contiguous to biosynthetic genes that we have already described ( nrps and pks ), resulting as part of the biosynthetic cluster. The encoded protein is responsible of the introduction of chlorine atom in the final molecular structure and acts at the last step in the pathway. This study can be considered a continuation of an earlier study wherein we started to clarify the molecular basis of OTA biosynthesis in A. carbonarius , which has not been completely elucidated until now. This research represents an important step forward to a better understanding of the production mechanism, which will contribute to the development of improved control strategies to reduce the risk of OTA contamination in food products. |
| تدمد: | 1098-5336 0099-2240 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2fd14aee3347bc01bcc5e1d01a369416 https://doi.org/10.1128/aem.01209-16 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi.dedup.....2fd14aee3347bc01bcc5e1d01a369416 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 10985336 00992240 |
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