Flavones are among the major colorless pigments synthesized through branches of the flavonoid pathway in plants. However, due to the absence of a gene encoding flavone synthase (FNS) in the model plant Arabidopsis thaliana species, the regulatory mechanism of FNS-catalyzed flavone biosynthesis has rarely been studied in plants. Here, it was found that flavones play a predominant role in the elimination of excess reactive oxygen species (ROS) at high temperatures in colorless plant organs. A novel atypical subgroup 7 (SG7) R2R3-MYB transcription factor, CmMYB012, was found to be induced in response to prolonged high temperatures and to inhibit flavone biosynthesis by directly regulating CmFNS. Moreover, CmMYB012 was also found to inhibit anthocyanin biosynthesis by suppressing the expression of CmCHS, CmDFR, CmANS, and CmUFGT. CmMYB012 overexpression exerted a negative influence on plant fitness and pink flower color formation, while CmMYB012 suppression had the opposite effect in response to high temperatures. Our findings provide new insights into the mechanisms by which high temperatures regulate the metabolism of flavones and anthocyanins to affect plant fitness and flower color formation.

中文翻译：

---

一种新的转录因子CmMYB012抑制菊花高温下黄酮和花青素的生物合成

黄酮是植物中通过类黄酮途径分支合成的主要无色色素之一。然而，由于模型植物中缺乏编码黄酮合酶（FNS）的基因拟南芥FNS 催化黄酮生物合成的调控机制在植物中鲜有研究。在这里，人们发现黄酮在高温下在无色植物器官中消除过量的活性氧 (ROS) 中起主要作用。一种新的非典型亚组 7 (SG7) R2R3-MYB 转录因子 CmMYB012 被发现可响应长时间的高温而被诱导，并通过直接调节来抑制黄酮的生物合成CmFNS. 此外，还发现 CmMYB012 通过抑制CmCHS,CmDFR,CMNS， 和CmUFGT.CMMYB012过度表达对植物适应性和粉红色花朵的形成产生负面影响，而CMMYB012抑制对高温的反应具有相反的效果。我们的研究结果为高温调节黄酮和花青素代谢以影响植物适应性和花色形成的机制提供了新的见解。