A metabolomics-guided approach to discover Fusarium graminearum metabolites after removal of a repressive histone modification
A metabolomics-guided approach to discover Fusarium graminearum metabolites after removal of a repressive histone modification
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DOI：
10.1016/j.fgb.2019.103256
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发表时间：
2019-11-01
影响因子：
3
通讯作者：
Loesgen, Sandra
中科院分区：
文献类型：
--
作者：
Adpressa, Donovon A.;Connolly, Lanelle R.;Loesgen, Sandra
许多次生代谢物是由生物合成基因簇（bgc）产生的，这些基因簇在标准生长条件下被抑制，这使得发现新的生物活性化合物变得复杂。在镰刀菌属中，许多bgc存在于富含三甲基化组蛋白3赖氨酸27 （H3K27me3）的染色质中，这是一种与转录基因沉默相关的修饰。在这里，我们报告了利用缺乏H3K27甲基转移酶Kmt6的菌株将代谢物分配给基因的进展。为了指导分离工作，我们将遗传学与来自野生型和kmt6的液相色谱-质谱（LCMS）数据进行了多变量分析，从而鉴定出以前未知的F. graminearum化合物。我们发现了低分子量、氨基酸衍生的代谢物（n -乙基苯甲酸、n -苯乙酰胺、n -乙酰色胺）。我们发现了一个新的化合物，原fusarin，来源于fusarin生物合成。同样，我们通过使用kmt6突变体，而不是优化生长培养基，分离了大量的fusarstatin A， gibepyrone A， fusarpyrones A和B。为了增加在野生型中未被充分代表的代谢物的丰度，我们产生了kmt6 fus1双突变体，并发现了三吲哚酮和三吲哚酸这两种新的三吲哚类倍半萜。我们的方法允许快速可视化和分析代谢物产生的遗传诱导变化，并通过化学和遗传去复制的结合发现新分子。在鉴定的22种真菌代谢产物中，有10种化合物是以前未报道过的。我们的研究表明，通过抑制染色质修饰酶的突变激活沉默的代谢途径，即使在一个被充分研究的生物体中，也可以发现新的化学物质，并有助于将新的或已知的小分子与负责其产生的bgc联系起来。
Many secondary metabolites are produced by biosynthetic gene clusters (BGCs) that are repressed during standard growth conditions, which complicates the discovery of novel bioactive compounds. In the genus Fusarium, many BGCs reside in chromatin enriched for trimethylated histone 3 lysine 27 (H3K27me3), a modification correlated with transcriptional gene silencing. Here we report on our progress in assigning metabolites to genes by using a strain lacking the H3K27 methyltransferase, Kmt6. To guide isolation efforts, we coupled genetics to multivariate analysis of liquid chromatography-mass spectrometry (LCMS) data from both wild type and kmt6, which allowed identification of compounds previously unknown from F. graminearum. We found low molecular weight, amino acid-derived metabolites (N-ethyl anthranilic acid, N-phenethylacetamide, N-acetyltryptamine). We identified one new compound, protofusarin, as derived from fusarin biosynthesis. Similarly, we isolated large amounts of fusaristatin A, gibepyrone A, and fusarpyrones A and B, simply by using the kmt6 mutant, instead of having to optimize growth media. To increase the abundance of metabolites underrepresented in wild type, we generated kmt6 fus1 double mutants and discovered tricinolone and tricinolonoic acid, two new sesquiterpenes belonging to the tricindiol class. Our approach allows rapid visualization and analyses of the genetically induced changes in metabolite production, and discovery of new molecules by a combination of chemical and genetic dereplication. Of 22 fungal metabolites identified here, 10 compounds had not been reported from F. graminearum before. We show that activating silent metabolic pathways by mutation of a repressive chromatin modification enzyme can result in the discovery of new chemistry even in a well-studied organism, and helps to connect new or known small molecules to the BGCs responsible for their production.