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.

中文翻译：

---

代谢组学指导的方法在去除抑制性组蛋白修饰后发现镰孢镰刀菌代谢物。

许多次级代谢产物是由生物合成基因簇（BGC）产生的，在标准生长条件下会受到抑制，这使新型生物活性化合物的发现变得复杂。在镰刀菌属中，许多BGC位于富含三甲基化组蛋白3赖氨酸27（H3K27me3）的染色质中，这种修饰与转录基因沉默相关。在这里，我们报告了通过使用缺乏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，我们将遗传学与野生型和kmt6液相色谱-质谱（LCMS）数据的多变量分析相结合，从而可以鉴定出禾谷镰刀菌以前未知的化合物。我们发现了低分子量，氨基酸衍生的代谢物（N-乙基邻氨基苯甲酸，N-苯乙基乙酰胺，N-乙酰色胺）。我们鉴定了一种从富沙林生物合成中衍生出来的新化合物，原藤黄素。同样，我们仅通过使用kmt6突变体即可分离出大量的富沙地他汀A，吉贝比隆A，以及呋喃沙酮A和B，而不必优化生长培养基。为了增加在野生型中代表性不足的代谢物的丰度，我们生成了kmt6 fus1双突变体，并发现了曲诺龙和三环戊二酸，这是两个新的倍半萜类三倍醇类。我们的方法可以快速观察和分析代谢产物生产中遗传诱导的变化，并通过化学和遗传去复制的组合来发现新分子。在此鉴定的22种真菌代谢产物中，以前从未从禾谷镰刀菌中报告过10种化合物。