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bioRxiv · 10.1101/2023.06.23.546348

Hyperosmolarity-induced suppression of group B1 Raf-like protein kinases modulates drought-growth trade-off in Arabidopsis

Kamiyama, Y.·Katagiri, S.·Yamashita, K.·Li, Y.·Takase, H.·Umezawa, T.
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Abstract

When plants are exposed to drought stress, there is a trade-off between plant growth and stress responses. Here, we identified a signaling mechanism for the initial steps of the drought-growth trade-off. Phosphoproteomic profiling revealed that Raf13, a B1 subgroup Raf-like kinase, is dephosphorylated under drought conditions. Raf13 and the related B1-Raf Raf15 are required for growth rather than the acquisition of osmotolerance. We also found that Raf13 interacts with B55-family regulatory subunits of protein phosphatase 2A (PP2A), which mediates hyperosmolarity-induced dephosphorylation of Raf13. In addition, Raf13 interacts with an AGC kinase INCOMPLETE ROOT HAIR ELONGATION HOMOLOG 1 (IREH1), and Raf13 and IREH1 have similar functions in regulating cellular responses that promote plant growth. Overall, our results support a model in which Raf13-IREH1 activity promotes growth under nonstressed conditions, whereas PP2A activity suppresses Raf13-IREH1 during osmotic stress to modulate the physiological "trade-off" between plant growth and stress responses.

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Kamiyama, Y., Katagiri, S., Yamashita, K., Li, Y., Takase, H., Umezawa, T.. 2023-06-25. Hyperosmolarity-induced suppression of group B1 Raf-like protein kinases modulates drought-growth trade-off in Arabidopsis. https://doi.org/10.1101/2023.06.23.546348

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