A dual function of SnRK2 kinases in the regulation of SnRK1 and plant growth

Adverse environmental conditions trigger responses in plants that promote stress tolerance and survival at the expense of growth1. However, little is known of how stress signalling pathways interact with each other and with growth regulatory components to balance growth and stress responses. Here, we show that plant growth is largely regulated by the interplay between the evolutionarily conserved energy-sensing SNF1-related protein kinase 1 (SnRK1) protein kinase and the abscisic acid (ABA) phytohormone pathway. While SnRK2 kinases are main drivers of ABA-triggered stress responses, we uncover an unexpected growth-promoting function of these kinases in the absence of ABA as repressors of SnRK1. Sequestration of SnRK1 by SnRK2 containing complexes inhibits SnRK1 signalling, thereby allowing target of rapamycin (TOR) activity and growth under optimal conditions. On the other hand, these complexes are essential for releasing and activating SnRK1 in response to ABA, leading to the inhibition of TOR and growth under stress. This dual regulation of SnRK1 by SnRK2 kinases couples growth control with environmental factors typical for the terrestrial habitat and is likely to have been critical for the water-to-land transition of plants.

Description

This work was supported by Fundação para a Ciência e a Tecnologia through the R&D Units UIDB/04551/2020 (GREEN-IT—Bioresources for Sustainability) and UID/MAR/04292/2019, FCT project nos. PTDC/BIA-PLA/7143/2014, LISBOA-01-0145-FEDER-028128 and PTDC/ BIA-BID/32347/2017, and FCT fellowships/contract nos. SFRH/BD/122736/2016 (M.A.), SFRH/BPD/109336/2015 (A.C.), PD/BD/150239/2019 (D.R.B.), and IF/00804/2013 (E.B.G.). Work in P.L.R.’s laboratory was funded by MCIU grant no. BIO2017-82503-R. C.M. thanks the LabEx Paris Saclay Plant Sciences-SPS (ANR-10-LABX-040-SPS) for support. B.B.P. was funded by Programa VALi+d GVA APOSTD/2017/039. This project has received funding from the European Union Horizon 2020 research and innovation programme (grant agreement no. 867426—ABA-GrowthBalance—H2020-WF-2018-2020/H2020-WF-01-2018, awarded to B.B.P.).

URI

http://hdl.handle.net/10400.8/5941

Citation

Belda-Palazón, B., Adamo, M., Valerio, C., Ferreira, L.J., Confraria, A., Reis-Barata, D., Rodrigues, A., Meyer, Christian, Rodriguez, P.L., & Baena-González, E. (2020). A dual function of SnRK2 kinases in the regulation of SnRK1 and plant growth. Nature Plants. https://doi.org/10.1038/ s41477-020-00778-w