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

作者：Huihuang Chen, Linlin Qi, Minxia Zou, Mengting Lu, Mateusz Kwiatkowski, Yuanrong Pei, Krzysztof Jaworski, Jiřı́ Friml · 发表于：Nature · 年份：2025 · DOI：10.1038/s41586-025-08669-w · 被引用次数：57 · 研究领域：Plant Molecular Biology Research、Plant tissue culture and regeneration、Light effects on plants

Abstract 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 factors 1–3 . Here we revise this paradigm by showing that without TIR1 adenylate cyclase (AC) activity 4 , 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.