基于转录组分析紫色红曲霉全局性转录调控因子McrA的功能

Transcriptome analysis reveals the function of the global transcriptional regulator McrA in Monascus purpureus

摘要:

红曲霉作为传统发酵食用菌因其丰富的次级代谢产物广泛应用于酿酒、食品着色剂和药品等行业。McrA是在构巢曲霉(Aspergillus nidulans)中发现的全局性转录调控因子，具有调控丝状真菌生长发育和次级代谢的作用。前期，实验室已找到并克隆了紫色红曲霉(Monascus purpureus)中的mcrA基因。目的 基于转录组分析ΔmcrA和trpC:mcrA差异表达基因，探究mcrA基因的功能。方法 利用同源重组的方法构建ΔmcrA和trpC:mcrA菌株，观察其在不同培养基上的菌落和显微形态，测定红曲色素和桔霉素产量，并进行转录组测序分析差异表达基因涉及的代谢通路。结果 敲除株ΔmcrA的红曲色素和桔霉素产量下降。转录组测序结果显示，ΔmcrA菌株有111个基因上调，47个基因下调。ΔmcrA菌株差异基因涉及的代谢通路主要有糖酵解、丙酮酸代谢、脂肪酸合成、酪氨酸代谢等。trpC:mcrA菌株有1 199个基因上调，867个基因下调。trpC:mcrA差异基因涉及的代谢通路主要有色氨酸代谢、蔗糖和淀粉代谢、精氨酸和脯氨酸代谢、脂肪酸降解等。结论 McrA作为全局性转录调控因子，敲除和过表达会影响糖类、脂质、氨基酸相关代谢通路，进而影响次级代谢产物产量。

Abstract:

Monascus, as a genus of edible fungi used in fermentation, are widely used in various industries such as wine making, food colorants, and pharmaceuticals due to their abundant secondary metabolites. McrA, a global regulator discovered in Aspergillus nidulans, has the function of regulating the growth and secondary metabolism of filamentous fungi. We had identified and cloned mcrA in Monascus purpureus in the previous study.Objective On the basis of transcriptome analysis, we mined the differentially expressed genes (DEGs) of ΔmcrA and trpC:mcrA strains to explore the function of mcrA.Methods The knockout strain ΔmcrA and overexpression strain trpC:mcrA of M. purpureus were constructed by homologous recombination. The colonies and microscopic morphology on different media were observed. The yields of Monascus pigments and citrinin were determined. The metabolic pathways involving DEGs were analyzed by transcriptome sequencing.Results The yields of Monascus pigments and citrinin of ΔmcrA decreased. Transcriptome sequencing results showed that the ΔmcrA strain up-regulated 111 genes and down-regulated 47 genes. The metabolic pathways involving the DEGs of ΔmcrA were mainly glycolysis, pyruvate metabolism, fatty acid synthesis, tyrosine metabolism and so on. The trpC:mcrA strain up-regulated 1 199 genes and down-regulated 867 genes. The main metabolic pathways involving the DEGs of trpC:mcrA were tryptophan metabolism, sucrose and starch metabolism, arginine and proline metabolism, fatty acid degradation, etc.Conclusion McrA is a global transcriptional regulator, and the knockout and overexpression of its gene will affect carbohydrate, lipid, and amino acid-related metabolic pathways, thus affecting the production of secondary metabolites.