Amplification and diversity analysis of ketosynthase domains of putative polyketide synthase genes in <i>Aspergillus ochraceus</i> and <i>Aspergillus carbonarius</i> producers of ochratoxin A

Atoui, Ali; Dao, Huy Phong; Mathieu, Florence; Lebrihi, Ahmed

doi:10.1002/mnfr.200500165

Cited by 38 publications

(44 citation statements)

References 24 publications

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“…So far, in Aspergillus spp., specifically in A. ochraceus (41) and in A. westerdijkiae (6), only the pks genes involved in the initial steps of the pathway have been characterized. In A. carbonarius, an economically and scientifically interesting species due to its predominant role in the contamination of grapes, the presence of different pks genes was investigated (5). In our previous work, we identified an additional pks gene in the same species whose expression pattern showed a correlation to OTA production under permissive conditions (22).…”

mentioning

confidence: 99%

New Insight into the Ochratoxin A Biosynthetic Pathway through Deletion of a Nonribosomal Peptide Synthetase Gene in Aspergillus carbonarius

Gallo

Bruno

Solfrizzo

et al. 2012

Appl Environ Microbiol

104

102

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bOchratoxin A (OTA), a mycotoxin produced by Aspergillus and Penicillium species, is composed of a dihydroisocoumarin ring linked to phenylalanine, and its biosynthetic pathway has not yet been completely elucidated. Most of the knowledge regarding the genetic and enzymatic aspects of OTA biosynthesis has been elucidated in Penicillium species. In Aspergillus species, only pks genes involved in the initial steps of the pathway have been partially characterized. In our study, the inactivation of a gene encoding a nonribosomal peptide synthetase (NRPS) in OTA-producing A. carbonarius ITEM 5010 has eliminated the ability of this fungus to produce OTA. This is the first report on the involvement of an nrps gene product in OTA biosynthetic pathway in an Aspergillus species. The absence of OTA and ochratoxin ␣, the isocoumaric derivative of OTA, and the concomitant increase of ochratoxin ␤, the dechloro analog of ochratoxin ␣, were observed in the liquid culture of transformed strain. The data provide the first evidence that the enzymatic step adding phenylalanine to polyketide dihydroisocoumarin precedes the chlorination step to form OTA in A. carbonarius and that ochratoxin ␣ is a product of hydrolysis of OTA, giving an interesting new insight into the biosynthetic pathway of the toxin.

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mentioning

confidence: 99%

New Insight into the Ochratoxin A Biosynthetic Pathway through Deletion of a Nonribosomal Peptide Synthetase Gene in Aspergillus carbonarius

Gallo

Bruno

Solfrizzo

et al. 2012

Appl Environ Microbiol

104

102

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“…The obtained pks gene sequences were then compared with the database in the National Center for Biotechnology and Information (NCBI) using the BLAST search tool. The fragment was confirmed as pks based on 98% identity with the already published A. carbonarius pks sequence (Atoui et al, 2006). …”

Section: Ota Cloning and Sequencing Analysismentioning

confidence: 58%

“…The resulting amplicon was then cloned into a plasmid. The sequence of the amplicon had a 98% identity to the published A. carbonarius polyketide synthase 5 (accession number: HM026487) in GenBank (Atoui et al, 2006).…”

Section: Discussionmentioning

confidence: 96%

Quantification of Ochratoxin A–Producing Fungi in Coffee Products Using Quantitative PCR

Potipun¹,

Ruaylarb²,

Nilthong³

et al. 2018

CMUJNS

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Ochratoxin A (OTA) is a polyketide mycotoxin that is produced by Aspergillus and Penicillium. Food contaminated with OTA poses health risks and is a food-safety challenge. Quantitative polymerase chain reaction (qPCR) has been used to identify non-toxigenic and toxigenic strains from coffee samples using polyketide synthase (pks), the OTA synthesis gene. In this research, Aspergillus carbonarius (ochratoxin-producing strain) and A. flavus (non-ochratoxin-producing strain) were used to amplify a 141 bp fragment of the pks gene. The 141 bp PCR product was successfully cloned into TOPO ® TA plasmid. Subsequently, ten-fold dilutions of plasmid DNA were used to generate the standard curve by plotting the threshold cycle against log DNA concentration using qPCR. Further, fungal DNA contamination was quantified in 11 samples of roasted coffee using qPCR. All 11 coffee samples were accepted as safe, since the fungal genomic DNA contamination was less than 3.85 x 10 3 copies. Therefore, this research suggested that qPCR is a fast and accurate method to detect and quantify OTA-producing fungi in coffee products. Thus, we successfully developed a system to quantify fungal contamination in coffee.

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“…However, in contrast to others mycotoxin, the OTA biosynthetic pathway was not well characterized in any of the OTA-producing species and consequently the genes that encode enzymes involved in the biosynthesis of this secondary metabolite are poor known. Based on OTA structure the necessity of various enzymes catalyzing key reactions in the formation of OTA can be expected and some teams of researchers are looking for the genes related to OTA biosynthesis (Lebrihi et al, 2003;Geisen et al, 2004;Atoui et al, 2006;O'Callaghan et al, 2006;Bogs et al, 2006). A polyketide synthase can be postulated as involved in OTA biosynthesis, because isocoumarin group of the OTA is probably a pentaketide formed from acetate and malonate via a polyketide synthesis pathway (O'Callaghan et al, 2003).…”

Section: Molecular Detection Of Ochratoxigenic Fungimentioning

confidence: 99%

An overview on molecular markers for detection of ochratoxigenic fungi in coffee neans

Fungaro

Sartori

2009

Braz. arch. biol. technol.

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Amplification and diversity analysis of ketosynthase domains of putative polyketide synthase genes in Aspergillus ochraceus and Aspergillus carbonarius producers of ochratoxin A

Cited by 38 publications

References 24 publications

New Insight into the Ochratoxin A Biosynthetic Pathway through Deletion of a Nonribosomal Peptide Synthetase Gene in Aspergillus carbonarius

New Insight into the Ochratoxin A Biosynthetic Pathway through Deletion of a Nonribosomal Peptide Synthetase Gene in Aspergillus carbonarius

Quantification of Ochratoxin A–Producing Fungi in Coffee Products Using Quantitative PCR

An overview on molecular markers for detection of ochratoxigenic fungi in coffee neans

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