Clustered array of ochratoxin A biosynthetic genes in Aspergillus steynii and their 1 expression patterns in permissive conditions



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Gil-Serna, Jessica and Vázquez Estévez, Covadonga and González-Jaén, María Teresa and Patiño Álvarez, Belén (2015) Clustered array of ochratoxin A biosynthetic genes in Aspergillus steynii and their 1 expression patterns in permissive conditions. International Journal of Food Microbiology, 214 . pp. 102-108. ISSN 0168-1605

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Aspergillus steynii is probably the most relevant species of section Circumdati producing ochratoxin A (OTA). This
mycotoxin contaminates a wide number of commodities and it is highly toxic for humans and animals. Little is known on the biosynthetic genes and their regulation in Aspergillus species. In this work, we identified and analysed three contiguous genes in A. steynii using 5′-RACE and genome walking approaches which predicted a cytochrome P450 monooxygenase (p450ste), a non-ribosomal peptide synthetase (nrpsste) and a polyketide synthase (pksste). These three genes were contiguous within a 20742 bp long genomic DNA fragment. Their corresponding cDNA were sequenced and their expression was analysed in three A. steynii strains using real time RT-PCR specific assays in permissive conditions in in vitro cultures. OTA was also analysed in these cultures. Comparative analyses of predicted genomic, cDNA and amino acid sequences were performed with sequences of similar gene functions. All the results obtained in these analyseswere consistent and point out the involvement of these three genes in OTA biosynthesis by A. steynii and showed a co-ordinated expression pattern. This is the first time that a clustered organization OTA biosynthetic genes has been reported in Aspergillus genus. The results also suggested that this situation might be common in Aspergillus OTA-producing species and distinct to the one described for Penicillium species.

Item Type:Article
Uncontrolled Keywords:Polyketide synthase, Non-ribosomal peptide synthetase, Cytochrome p450 47 monooxygenase, Aspergillus steynii, ochratoxin A, biosynthetic cluster
Subjects:Medical sciences > Biology > Genetics
Medical sciences > Biology > Microbiology
ID Code:33217
Deposited On:24 Sep 2015 06:52
Last Modified:10 Dec 2018 15:30

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