KAI2 regulates seedling development by mediating light-induced remodelling of auxin transport.
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Hamon-Josse, M., Villaécija-Aguilar, J. A., Ljung, K., Leyser, O., Gutjahr, C., & Bennett, T. (2022). KAI2 regulates seedling development by mediating light-induced remodelling of auxin transport.. New Phytol https://doi.org/10.1111/nph.18110
Funder: Swedish Research Council; Id: http://dx.doi.org/10.13039/501100004359
Funder: Knut and Alice Wallenberg Foundation; Id: http://dx.doi.org/10.13039/501100004063
Funder: Swedish Governmental Agency for Innovation Systems; Id: http://dx.doi.org/10.13039/501100001858
Photomorphogenic remodelling of seedling growth is a key developmental transition in the plant life cycle. The α/β-hydrolase signalling protein KARRIKIN-INSENSITIVE2 (KAI2), a close homologue of the strigolactone receptor DWARF14 (D14), is involved in this process, but it is unclear how the effects of KAI2 on development are mediated. Here, using a combination of physiological, pharmacological, genetic and imaging approaches in Arabidopsis thaliana (Heynh.) we show that kai2 phenotypes arise because of a failure to downregulate auxin transport from the seedling shoot apex towards the root system, rather than a failure to respond to light per se. We demonstrate that KAI2 controls the light-induced remodelling of the PIN-mediated auxin transport system in seedlings, promoting a reduction in PIN7 abundance in older tissues, and an increase of PIN1/PIN2 abundance in the root meristem. We show that removing PIN3, PIN4 and PIN7 from kai2 mutants, or pharmacological inhibition of auxin transport and synthesis, is sufficient to suppress most kai2 seedling phenotypes. We conclude that KAI2 regulates seedling morphogenesis by its effects on the auxin transport system. We propose that KAI2 is not required for the light-mediated changes in PIN gene expression but is required for the appropriate changes in PIN protein abundance within cells.
Full paper, Full papers, Arabidopsis, auxin, auxin transport, KAI2 signalling, light signalling, PIN proteins, seedling development
Biotechnology and Biological Sciences Research Council (BB/R00398X/1)
Gatsby Charitable Foundation (GAT3272C)
Deutsche Forschungsgemeinschaft (GU1423/1‐1)
External DOI: https://doi.org/10.1111/nph.18110
This record's URL: https://www.repository.cam.ac.uk/handle/1810/335946