Abstract
The phytohormone auxin is the major coordinative signal in plant development, mediating transcriptional reprogramming by a well-established canonical signalling pathway. TRANSPORT INHIBITOR RESPONSE 1 (TIR1)/AUXIN-SIGNALING F-BOX (AFB) auxin receptors are F-box subunits of ubiquitin ligase complexes. In response to auxin, they associate with Aux/IAA transcriptional repressors and target them for degradation via ubiquitination. Here we identify adenylate cyclase (AC) activity as an additional function of TIR1/AFB receptors across land plants. Auxin, together with Aux/IAAs, stimulates cAMP production. Three separate mutations in the AC motif of the TIR1 C-terminal region, all of which abolish the AC activity, each render TIR1 ineffective in mediating gravitropism and sustained auxin-induced root growth inhibition, and also affect auxin-induced transcriptional regulation. These results highlight the importance of TIR1/AFB AC activity in canonical auxin signalling. They also identify a unique phytohormone receptor cassette combining F-box and AC motifs, and the role of cAMP as a second messenger in plants.
Original language | English |
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Pages (from-to) | 133-138 |
Number of pages | 6 |
Journal | Nature |
Volume | 611 |
Early online date | 26 Oct 2022 |
DOIs | |
Publication status | Published - 3 Nov 2022 |
Bibliographical note
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Funder
Funding Information: This research was supported by the Lab Support Facility (LSF) and the Imaging and Optics Facility (IOF) of IST Austria. We thank C. Gehring for suggestions and advice; and K. U. Torii and G. Stacey for seeds and plasmids. This project was funded by a European Research Council Advanced Grant (ETAP-742985). M.F.K. and R.N. acknowledge the support of the EU MSCA-IF project CrysPINs (792329). M.K. was supported by the project POWR.03.05.00-00-Z302/17 Universitas Copernicana Thoruniensis in Futuro–IDS “Academia Copernicana”. CIDG acknowledges support from UKRI under Future Leaders Fellowship grant number MR/T020652/1. .
Keywords
- Adenylyl Cyclases - genetics - metabolism
- Arabidopsis - enzymology - metabolism
- Arabidopsis Proteins - genetics - metabolism
- Cyclic AMP - metabolism
- F-Box Proteins - genetics - metabolism
- Gene Expression Regulation, Plant
- Gravitropism
- Indoleacetic Acids - metabolism - pharmacology
- Mutation
- Plant Growth Regulators - pharmacology - metabolism
- Plant Roots - growth & development
- Receptors, Cell Surface - genetics - metabolism
- Second Messenger Systems