ABSTRACT

Plant long noncoding RNAs (lncRNAs) are key chromatin dynamics regulators, directing the transcriptional programs driving a wide variety of developmental outputs. Recently, we uncovered how the lncRNA AUXIN REGULATED PROMOTER LOOP (APOLO) directly recognizes the locus encoding the root hair (RH) master regulator ROOT HAIR DEFECTIVE 6 (RHD6) modulating its transcriptional activation and leading to low temperature-induced RH elongation. We further demonstrated that APOLO interacts with the transcription factor WRKY42 in a novel ribonucleoprotein complex shaping RHD6 epigenetic environment and integrating signals governing RH growth and development. In this work, we expand this model showing that APOLO is able to bind and positively control the expression of several cell wall EXTENSIN (EXT) encoding genes, including EXT3, a key regulator for RH growth. Interestingly, EXT3 emerged as a novel common target of APOLO and WRKY42. Furthermore, we showed that the ROS homeostasis-related gene NADPH OXIDASE C (NOXC) is deregulated upon APOLO overexpression, likely through the RHD6-RSL4 pathway, and that NOXC is required for low temperature-dependent enhancement of RH growth. Collectively, our results uncover an intricate regulatory network involving the APOLO/WRKY42 hub in the control of master and effector genes during RH development.

摘要

植物长链非编码 RNA (lncRNA) 是关键的染色质动力学调节剂，指导转录程序驱动各种发育输出。最近，我们发现了 lncRNA AUXIN REGULATED PROMOTER LOOP ( APOLO ) 如何直接识别编码根毛 (RH) 主调节子ROOT HAIR DEFECTIVE 6 ( RHD6 ) 的基因座，从而调节其转录激活并导致低温诱导的 RH 伸长。我们进一步证明了APOLO与形成RHD6的新型核糖核蛋白复合物中的转录因子 WRKY42相互作用表观遗传环境和整合控制 RH 生长和发育的信号。在这项工作中，我们扩展了这个模型，表明APOLO能够结合并积极控制几个细胞壁 EXTENSIN (EXT) 编码基因的表达，包括EXT3，这是 RH 生长的关键调节因子。有趣的是，EXT3成为APOLO和 WRKY42 的一个新的共同目标。此外，我们发现 ROS 稳态相关基因NADPH OXIDASE C (NOXC)在APOLO过表达时失调，可能通过 RHD6-RSL4 途径，并且NOXCRH 生长的低温依赖性增强是必需的。总的来说，我们的研究结果揭示了一个复杂的调节网络，涉及APOLO / WRKY42 枢纽，在 RH 发育过程中控制主基因和效应基因。