Ambient temperature is a pivotal factor in the regulation of the flowering process in plants. In this study, we found that high ambient temperature exerts an inhibitory effect on the flowering of Osmanthus fragrans “Sjigui”. However, the underlying molecular mechanisms remain not fully understood. Through transcriptome analysis, a differently expressed C3H gene OfC3H49 was identified, which is induced by high ambient temperature. OfC3H49 was demonstrated to delay the flowering process of Arabidopsis and to downregulate the expression of flowering-related genes in O. fragrans calli. Further investigation indicates that OfC3H49 as a transcriptional repressor, directly suppresses the expression of the OfSOC1B thereby causing a delay in flowering time. Furthermore, a WRKY transcription factor, OfWRKY17, was identified to be responsive to high ambient temperature, directly binding to the OfC3H49 promoter and enhance OfC3H49 expression. Overexpression of OfWRKY17 in Arabidopsis resulted in a significant delay in flowering and induced the expression of OfC3H49 in O. fragrans calli. Collectively, our findings delineate a regulatory module, OfWRKY17-OfC3H49, which is activated by high ambient temperature and functions as a negative regulator of flowering by suppressing the expression of OfSOC1B in O. fragrans. This study provides novel insights into the molecular mechanisms involved in ambient temperature-mediated flowering control and contributes to the development of molecular breeding strategies for O. fragrans.

中文翻译：

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OfWRKY17-OfC3H49模块响应高环境温度通过抑制桂花中OfSOC1B的表达延迟开花


环境温度是调节植物开花过程的关键因素。本研究发现，较高的环境温度对桂花“桂花”的开花有抑制作用。然而，潜在的分子机制仍未完全了解。通过转录组分析，鉴定出C3H49的差异表达的C3H基因，该基因是由高环境温度诱导的。 C3H49被证明可以延迟拟南芥的开花过程并下调桂花愈伤组织中开花相关基因的表达。进一步研究表明，OfC3H49 作为转录抑制子，直接抑制 OfSOC1B 的表达，从而导致开花时间延迟。此外，WRKY转录因子OfWRKY17被发现对高环境温度有反应，直接结合OfC3H49启动子并增强OfC3H49表达。 OfWRKY17在拟南芥中的过度表达导致开花显着延迟并诱导OfC3H49在桂花愈伤组织中的表达。总的来说，我们的研究结果描绘了一个调节模块 OfWRKY17-OfC3H49，它被高环境温度激活，并通过抑制 OfSOC1B 在桂花中的表达而发挥开花负调节因子的作用。这项研究为环境温度介导的开花控制所涉及的分子机制提供了新的见解，并有助于制定香桂分子育种策略。