State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China.
Jiangxi-OAI Joint Research Institute, Nanchang University, Nanchang, China.
J Basic Microbiol. 2020 Oct;60(10):873-881. doi: 10.1002/jobm.202000059. Epub 2020 Aug 18.
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.
桔青霉中桔霉素的应用受到限制。因此，探索桔霉素的合成途径以完全抑制桔霉素的产生非常重要。在我们之前的研究中，我们发现 ctnF 基因编码的蛋白与果糖-2,6-二磷酸酶（F26BPase）具有显著的相似性。通常情况下，双功能酶 F26BPase 调节糖酵解通量。因此，我们推测 CtnF 蛋白增强了碳通量向乙酰辅酶 A 和丙二酰辅酶 A 的流动，这是桔霉素和色素合成的前体化合物。在这项研究中，构建了 ctnF 基因靶向载体 pctnF-HPH，并转化到桔青霉中。通过四组引物和聚合酶链反应扩增筛选出 ctnF 缺陷型菌株。与野生型菌株相比，缺陷型菌株中的桔霉素含量降低了 34%，色素产量降低了 72%。这些结果表明 ctnF 基因参与了桔霉素和色素的共同合成，这与之前的推测一致。
