茶叶培养基对海洋冠突散囊菌代谢路径的调控

Regulation of metabolic pathways of ocean originated Eurotium cristatum by tea leaf medium

摘要:

【背景】 为更好地适应生境，真菌会产生种类多样的次级代谢物。【目的】 探究来自茯砖茶和海洋2种生境下的冠突散囊菌(Eurotium cristatum)在PDA培养基中的次级代谢物差异、茶叶培养基对海洋冠突散囊菌代谢产物的调控规律及其可能的机制。【方法】 利用液相色谱-质谱联用技术并结合基于特征物信息的质谱分子网络方法，分析了2种冠突散囊菌在PDA培养基中的次级代谢物差异，并利用多种多元统计方法分析了海洋冠突散囊菌在茶叶培养基中的非挥发性代谢物变化规律。此外，我们还研究了直接和非直接碳源对其次级代谢物的影响规律。【结果】 2种生境中的冠突散囊菌在聚酮的合成能力方面相似，而在非核糖体肽的合成方面有显著区别。其中，茯砖茶冠突散囊菌能产生异戊烯基环二肽，而海洋冠突散囊菌则能产生寡肽。5 d左右的茶叶培养基驯化，促使海洋冠突散囊菌的次级代谢通路发生了变化。海洋冠突散囊菌在茶叶培养基中的一些次级代谢物与其在非直接碳源培养基中相同。【结论】 来自2种生境的冠突散囊菌的次级代谢路径有显著差异，茶叶培养基短时间的驯化促使海洋冠突散囊菌的次级代谢路径发生了一些变化，部分原因可能是源于其碳代谢抑制的解除。

Abstract:

[Background] Fungi produce diverse secondary metabolites to adapt to their habitats. [Objective] To compare the secondary metabolites of Eurotium cristatum strains from two habitats (Fuzhuan brick tea and ocean) in PDA and explore the regulatory effect and mechanism of the tea leaf medium on the metabolites of ocean originated E. cristatum. [Methods] Liquid chromatography-mass spectrometry combined with feature-based molecular networking was employed to analyze the differences of secondary metabolites of the two strains of E. cristatum, and the changes in non-volatile metabolites of the ocean originated strain in the tea leaf medium were analyzed by the multivariate statistical method. In addition, we investigated the effects of indirect and direct carbon sources on the secondary metabolites of the ocean originated strain. [Results] Firstly, the two strains of E. cristatum presented similar polyketone synthesis capacity but significant differences in non-ribosomal peptide synthesis. Specifically, the tea-derived strain produced isopentenyl cyclic dipeptide, while the ocean originated strain produced oligopeptides. Secondly, the domestication in the tea leaf medium for 5 days induced changes in the secondary metabolic pathways of the ocean originated strain. Finally, some metabolites of the ocean originated strain in the tea leaf medium were identical to those in the medium with indirect carbon source. [Conclusion] There were significant differences in the secondary metabolic pathways between E. cristatum strains from the two habitats. The short-term domestication in the tea leaf medium changes the secondary metabolic pathways of the ocean originated strain, which may be partly due to the lifting of carbon catabolite repression.