基于比较代谢组学解析藤仓赤霉菌CGMCC 17793高产GA4机制

Comparative metabolomics reveals the mechanism for the high GA4 production in Gibberella fujikuroi CGMCC 17793

摘要:

新型赤霉素(gibberellin) GA4因其独特的优势而具有广阔的应用前景。为探究GA₄生物合成调控机制，本研究以藤仓赤霉菌(Gibberella fujikuroi) GA₄生产菌株S (CGMCC 17793)和野生菌株Y (GenBank登录号：NRRL 13620)为研究对象，利用液相色谱-质谱联用(liquid chromatograph-mass spectrometer,LC-MS)代谢组学技术，结合主成分分析(principal component analysis,PCA)与偏最小二乘-显著性分析联合法(partial least squares-discrimination analysis,PLS-DA)等对两种菌株在同一发酵时间以及菌株S在不同发酵时间的差异代谢物进行筛选与鉴定，并利用KEGG数据库和MBROLE 2.0分析相关代谢通路。结果表明，与菌株Y相比，菌株S在发酵3、6、9 d时，显著上调和下调的代谢物分别为107种和66种、136种和47种、94种和65种。与生产菌株S发酵3 d时相比，6、9 d时显著上调和下调的代谢物分别为29种和40种、52种和67种。菌株S与菌株Y同一发酵时间的差异代谢物主要富集在氨基酸代谢、三羧酸循环(tricarboxylic acid cycle,TCA cycle)和萜类生物合成等通路。菌株S不同发酵时间的差异代谢物主要富集在氨基酸代谢与糖代谢等合成途径。通路注释与分析结果说明，菌株S通过促进氨基酸与糖代谢、TCA循环产生更多乙酰CoA，增强了甲羟戊酸途径，从而使萜类化合物合成的前体物质异戊烯焦磷酸(isopentenyl pyrophosphate,IPP)含量增加，最终提高了GA₄产量。本研究探究了藤仓赤霉菌GA₄代谢规律，为调控藤仓赤霉菌提高GA₄产量提供了理论基础。

Abstract:

With unique advantages, gibberellin GA₄ has broad application prospects. To explore the regulatory mechanism for the biosynthesis of GA₄, we combined liquid chromatography- mass spectrometry (LC-MS)-based metabolomics with principal component analysis (principal component analysis, PCA) and partial least squares-discriminant analysis (PLS-DA) to screen and identify the differential metabolites between the GA₄-producing strains S (industrial high-yield strain CGMCC 17793) and wild-type strain Y (NRRL 13620) of Gibberella fujikuroi fermented for the same time and the differential metabolites of strain S fermented for different time periods. KEGG and MBROLE 2.0 were used to analyze the metabolic pathways involving the differential metabolites. The results showed that compared with strain Y, strain S significantly upregulated and downregulated 107 and 66, 136 and 47, and 94 and 65 metabolites on days 3, 6, and 9, respectively. Compared with that on day 3 of fermentation, strain S upregulated 29 metabolites and downregulated 40 metabolites on day 6 and upregulated 52 metabolites and downregulated 67 metabolites on day 9. The differential metabolites between strain S and strain Y after fermentation for the same time were mainly enriched in amino acid metabolism, tricarboxylic acid (TCA) cycle, and terpenoid biosynthesis. The differential metabolites of strain S after fermentation for different time periods were mainly enriched in amino acid and sugar metabolism pathways. Pathway annotation results indicated that strain S increased the production of acetyl-CoA by promoting amino acid and sugar metabolism and TCA cycle, thereby enhancing the mevalonic acid pathway and increasing the content of isopentenyl pyrophosphate (IPP), a precursor for the synthesis of terpenoids, which ultimately led to increased GA₄ production. This study explored the metabolic rules of Gibberella fujikuroi GA₄, providing a theoretical basis for regulating Gibberella fujikuroi to improve GA₄ production.