TIR1-produced cAMP as a second messenger in transcriptional auxin signalling

• 成果类型: Article
• 署名作者: Chen, Huihuang; Qi, Linlin; Zou, Minxia; Lu, Mengting; Kwiatkowski, Mateusz; Pei, Yuanrong; Jaworski, Krzysztof; Friml, Jiri
• 署名单位: Institute of Science & Technology - Austria; Shenzhen University of Advanced Technology; Shenzhen University of Advanced Technology; Chinese Academy of Sciences; Shenzhen Institute of Advanced Technology, CAS; Nicolaus Copernicus University
• 刊物名称: Nature
• ISSN/ISSBN: 0028-2371
• DOI: 10.1038/s41586-025-08669-w
• 发表日期: 2025-04-24
• 关键词: box protein tir1; degradation; repressors; FAMILY

摘要

The phytohormone auxin (Aux) is a principal endogenous developmental signal in plants. It mediates transcriptional reprogramming by a well-established canonical signalling mechanism. TIR1/AFB auxin receptors are F-box subunits of an ubiquitin ligase complex; after auxin perception, they associate with Aux/IAA transcriptional repressors and ubiquitinate them for degradation, thus enabling the activation of auxin response factor (ARF) transcription factors1, 2-3. Here we revise this paradigm by showing that without TIR1 adenylate cyclase (AC) activity4, auxin-induced degradation of Aux/IAAs is not sufficient to mediate the transcriptional auxin response. Abolishing the TIR1 AC activity does not affect auxin-induced degradation of Aux/IAAs but renders TIR1 non-functional in mediating transcriptional reprogramming and auxin-regulated development, including shoot, root, root hair growth and lateral root formation. Transgenic plants show that local cAMP production in the vicinity of the Aux/IAA-ARF complex by unrelated AC enzymes bypasses the need for auxin perception and is sufficient to induce ARF-mediated transcription. These discoveries revise the canonical model of auxin signalling and establish TIR1/AFB-produced cAMP as a second messenger essential for transcriptional reprograming.