• Fusarium graminearum produces the mycotoxin deoxynivalenol (DON) which promotes its expansion during infection on its plant host wheat. Conditional expression of DON production during infection is poorly characterized.
• Wheat produces the defense compound putrescine, which induces hypertranscription of DON biosynthetic genes (FgTRIs) and subsequently leads to DON accumulation during infection. Further, the regulatory mechanisms of FgTRIs hypertranscription upon putrescine treatment were investigated.
• The transcription factor FgAreA regulates putrescine-mediated transcription of FgTRIs by facilitating the enrichment of histone H2B monoubiquitination (H2B ub1) and histone 3 lysine 4 di- and trimethylations (H3K4 me2/3) on FgTRIs. Importantly, a DNA-binding domain (bZIP) specifically within the Fusarium H2B ub1 E3 ligase Bre1 othologs is identified, and the binding of this bZIP domain to FgTRIs depends on FgAreA-mediated chromatin rearrangement. Interestingly, H2B ub1 regulates H3K4 me2/3 via the methyltransferase complex COMPASS component FgBre2, which is different from Saccharomyces cerevisiae.
• Taken together, our findings reveal the molecular mechanisms by which host-generated putrescine induces DON production during F. graminearum infection. Our results also provide a novel insight into the role of putrescine during phytopathogen–host interactions and broaden our knowledge of H2B ub1 biogenesis and crosstalk between H2B ub1 and H3K4 me2/3 in eukaryotes.

中文翻译：

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植物防御化合物通过调节 H2B ub1 和 H3K4 me2/3 沉积触发霉菌毒素合成

• 禾谷镰刀菌产生霉菌毒素脱氧雪腐镰刀菌烯醇 (DON)，在其植物宿主小麦感染期间促进其扩张。感染期间 DON 产生的条件性表达缺乏特征。
• 小麦产生防御化合物腐胺，它诱导 DON 生物合成基因 ( FgTRI s) 的超转录，随后在感染期间导致 DON 积累。此外，研究了腐胺处理后FgTRI 超转录的调节机制。
• 转录因子 FgAreA通过促进组蛋白 H2B 单泛素化 (H2B ub1) 和组蛋白 3 赖氨酸 4 二甲基化和三甲基化 (H3K4 me2/3) 在FgTRIs上的富集来调节腐胺介导的 FgTRIs 转录。重要的是，确定了镰刀菌H2B ub1 E3 连接酶 Bre1 同源物中特异性的 DNA 结合域 (bZIP) ，并且该 bZIP 域与FgTRIs的结合取决于 FgAreA 介导的染色质重排。有趣的是，H2B ub1 通过甲基转移酶复合物 COMPASS 组分 FgBre2 调节 H3K4 me2/3，这与Saccharomyces cerevisiae不同。
• 总之，我们的研究结果揭示了宿主产生的腐胺在禾谷镰刀菌感染期间诱导 DON 产生的分子机制。我们的研究结果还为腐胺在植物病原体-宿主相互作用中的作用提供了新的见解，并拓宽了我们对真核生物中 H2B ub1 生物发生和 H2B ub1 和 H3K4 me2/3 之间的串扰的认​​识。