Real time quantitative expression study of a polyketide synthase gene related to ochratoxin a biosynthesis in Aspergillus niger

The estrogenic mycotoxin zearalenone (ZON) produced by some Fusarium spp. causes reproductive problems and hyperestrogenic syndromes in mammals. In an effort to elucidate the molecular pathways of ZON production, we present a comparative real-time quantitative polymerase chain reaction expression study of seven contiguous genes in the ZON biosynthetic cluster on sterile rice and during wheat and oat infection. Under ZON production on rice, the polyketide synthase (PKS) genes PKS4 and PKS13, alcohol oxidase FG12056 gene, and transcriptional regulator FG02398 gene showed similarly upregulated patterns, whereas the nonribosomal peptide synthetase (NPS) FG02394, the K+ channel β subunit FG12015, and the protein kinase FG02399 displayed a variant pattern. During the same time period under wheat infection when no ZON was produced, the PKS genes and the NPS were downregulated relative to rice whereas the K+ channel β subunit gene FG12015 was markedly upregulated, suggesting that it may play a role in the infection process. This is the first expression study of ZON biosynthetic genes in planta. The results give insight into the regulation and activities of the ZON gene cluster under different experimental systems and suggest a connection between ZON and a K+ channel that could reveal a novel function for ZON in Fusarium spp.

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Development of a Real Time PCR system for detection of ochratoxin A-producing strains of the Aspergillus niger aggregate

Food Control ◽

10.1016/j.foodcont.2011.02.014 ◽

2011 ◽

Vol 22 (8) ◽

pp. 1367-1372 ◽

Cited By ~ 20

Author(s):

G. Castellá ◽

F.J. Cabañes

Keyword(s):

Aspergillus Niger ◽

Real Time ◽

Ochratoxin A ◽

Real Time Pcr

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Cloning a part of the ochratoxin A biosynthetic gene cluster of Penicillium nordicum and characterization of the ochratoxin polyketide synthase gene

Systematic and Applied Microbiology ◽

10.1016/j.syapm.2005.03.008 ◽

2005 ◽

Vol 28 (7) ◽

pp. 588-595 ◽

Cited By ~ 80

Author(s):

Anja Karolewiez ◽

Rolf Geisen

Keyword(s):

Gene Cluster ◽

Ochratoxin A ◽

Polyketide Synthase ◽

Biosynthetic Gene Cluster ◽

Biosynthetic Gene ◽

Penicillium Nordicum ◽

Polyketide Synthase Gene

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A polyketide synthase gene required for ochratoxin A biosynthesis in Aspergillus ochraceus

Microbiology ◽

10.1099/mic.0.26619-0 ◽

2003 ◽

Vol 149 (12) ◽

pp. 3485-3491 ◽

Cited By ~ 115

Author(s):

J. O'Callaghan ◽

M. X. Caddick ◽

A. D. W. Dobson

Keyword(s):

Ochratoxin A ◽

Polyketide Synthase ◽

Subtractive Hybridization ◽

Polyketide Synthases ◽

Aspergillus Ochraceus ◽

Predicted Amino Acid Sequence ◽

Acyl Transferase ◽

Reverse Transcription Pcr ◽

Polyketide Synthase Gene

Ochratoxin A is an important nephrotoxic and nephrocarcinogenic mycotoxin, produced by Aspergillus ochraceus as a polyketide-derived secondary metabolite. A portion of a putative polyketide synthase gene (pks) involved in the biosynthesis of this mycotoxin was cloned by using a suppression subtractive hybridization PCR-based approach. The predicted amino acid sequence of the 1·4 kb clone shared 28–35 % identity to acyl transferase regions from fungal polyketide synthases found in the databases. Based on reverse transcription PCR studies, the pks gene is expressed only under ochratoxin A permissive conditions and only during the early stages of the mycotoxin synthesis. A mutant in which the pks gene has been interrupted cannot synthesize ochratoxin A. This report is the first of the cloning and characterization of a gene involved in ochratoxin A biosynthesis.

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