Abstract Expression of genes associated with cyclopiazonic acid (CPA) biosynthesis by Penicillium strains in a cheese-based medium has not been previously studied. To control CPA biosynthesis, it would be useful to understand the changes in gene expression during cheese production and relate them to toxin production. The objective of this study was to evaluate the influence of pH, a w , and temperature on expression of dma T, which encodes the enzyme dimethylallyl tryptophan synthase involved in the biosynthesis of CPA. We assayed three Penicillium strains, P. commune CBS311 and CBS341 and P. camemberti CBS273, using reverse transcription real-time PCR. Our results showed that the expression patterns of the gene were influenced by strain and environmental conditions. The highest expression for the P. commune strains was observed at pH 6.0, 0.95 a w , at 25 or 30 oC, depending on the strain. In contrast, P. camemberti CBS273 showed a lower dma T expression with a maximum at 25 oC, pH 5.0 and 0.95 a w . Correlation analysis indicated that the three toxigenic strains showed a strong correlation between the relative expression of the dma T gene and concentration of CPA under conditions simulating cheese ripening. This method could be used to control CPA production in cheese by detection of dma T expression.

中文翻译：

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环吡氮酸基因表达作为减少奶酪中霉菌毒素污染的策略

摘要 先前尚未研究过青霉属菌株在基于奶酪的培养基中表达与环吡氮酸 (CPA) 生物合成相关的基因。为了控制 CPA 生物合成，了解奶酪生产过程中基因表达的变化并将其与毒素生产联系起来会很有用。本研究的目的是评估 pH、aw 和温度对 dma T 表达的影响，dma T 编码参与 CPA 生物合成的二甲基烯丙基色氨酸合酶。我们使用逆转录实时 PCR 检测了三种青霉菌菌株，P.commune CBS311 和 CBS341 以及 P. camemberti CBS273。我们的结果表明该基因的表达模式受菌株和环境条件的影响。在 pH 6.0、0 时观察到 P. 公社菌株的最高表达。95 aw ，在 25 或 30 oC 下，取决于菌株。相比之下，P. camemberti CBS273 显示出较低的 dma T 表达，在 25 oC、pH 5.0 和 0.95 aw 时达到最大值。相关性分析表明，在模拟奶酪成熟的条件下，3株产毒菌株的dma T基因的相对表达量与CPA浓度之间具有很强的相关性。该方法可用于通过检测 dma T 表达来控制奶酪中 CPA 的产生。