Plant long noncoding RNAs (lncRNAs) have emerged as important regulators of chromatin dynamics, impacting on transcriptional programs leading to different developmental outputs. The lncRNA AUXIN REGULATED PROMOTER LOOP (APOLO) directly recognizes multiple independent loci across the Arabidopsis genome and modulates their three-dimensional chromatin conformation, leading to transcriptional shifts. Here, we show that APOLO recognizes the locus encoding the root hair (RH) master regulator ROOT HAIR DEFECTIVE 6 (RHD6) and controls RHD6 transcriptional activity leading to cold-enhanced RH elongation through the consequent activation of the transcription factor gene RHD6-like RSL4. Furthermore, we demonstrate that APOLO interacts with the transcription factor WRKY42 and modulates its binding to the RHD6 promoter. WRKY42 is required for the activation of RHD6 by low temperatures and WRKY42 deregulation impairs cold-induced RH expansion. Collectively, our results indicate that a novel ribonucleoprotein complex involving APOLO and WRKY42 forms a regulatory hub which activates RHD6 by shaping its epigenetic environment and integrates signals governing RH growth and development.

中文翻译：

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lncRNA APOLO与转录因子WRKY42相互作用，以响应感冒而触发根毛细胞扩增

植物长的非编码RNA（lncRNA）已作为染色质动力学的重要调节剂出现，影响导致不同发育输出的转录程序。lncRNA AUXIN调控启动子环（APOLO）可直接识别整个拟南芥基因组的多个独立基因座，并调节其三维染色质构象，从而导致转录移位。在这里，我们显示APOLO识别编码根毛（RH）主调节剂ROOT HAIR DEFECTIVE 6（RHD6）的基因座，并控制RHD6转录活性，从而通过转录因子基因RHD6-like RSL4的激活而导致冷增强RH伸长。 。此外，我们证明APOLO与转录因子WRKY42相互作用并调节其与RHD6启动子的结合。WRKY42是低温激活RHD6所必需的，而WRKY42的失调会削弱冷诱导的RH扩展。总的来说，我们的研究结果表明，涉及APOLO和WRKY42的新型核糖核蛋白复合物形成了一个调节中心，该调节中心通过塑造RHD6的表观遗传环境并整合控制RH生长发育的信号来激活它。