The application of Monascus is restricted by citrinin. So, it is important to explore the synthetic pathway of citrinin to completely inhibit the production of citrinin. In our previous study, we found that the protein encoded by the ctnF gene has a significant similarity to fructose‐2,6‐bisphosphatase (F26BPase). It is generally known that the bifunctional enzyme F26BPase regulates the glycolytic flux. So, we speculated that the CtnF protein strengthens carbon flux towards acetyl‐CoA and malonyl‐CoA which are precursor compounds in citrinin and pigment synthesis. In this study, the ctnF gene‐targeting vector pctnF‐HPH was constructed and transformed into Monascus aurantiacus. A ctnF‐deficient strain was selected by four sets of primers and polymerase chain reaction amplification. Compared with the wild‐type strain, citrinin content in the deficient strain was reduced by 34%, and the pigment production was decreased by 72%. These results indicate that the ctnF gene is involved in the common synthesis of citrinin and pigment, which is consistent with previous speculations.

中文翻译：

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ctnF基因参与红曲霉的桔霉素和色素合成

红曲霉的应用受到桔霉素的限制。因此，探索Citrinin的合成途径以完全抑制Citrinin的产生具有重要意义。在我们之前的研究中，我们发现由 ctnF 基因编码的蛋白质与果糖-2,6-双磷酸酶（F26BPase）具有显着的相似性。众所周知，双功能酶 F26BPase 调节糖酵解通量。因此，我们推测 CtnF 蛋白增强了朝向乙酰辅酶 A 和丙二酰辅酶 A 的碳通量，它们是桔霉素和色素合成中的前体化合物。本研究构建了ctnF基因靶向载体pctnF-HPH并将其转化到红曲霉中。通过四组引物和聚合酶链反应扩增选择了一个 ctnF 缺陷菌株。与野生型菌株相比，缺陷菌株中桔霉素含量减少了 34%，色素产量减少了 72%。这些结果表明ctnF基因参与了citrinin和色素的共同合成，这与之前的推测是一致的。