Evolutionary Roots and Mechanistic Principles of Auxin Response

Abstract

The small signaling molecule auxin controls numerous developmental processes in land plants, acting mostly by regulating gene expression. Key questions in auxin biology are how this chemically simple molecule can regulate such a large range of processes. While most of what the community has learned about auxin action is based on studies in flowering plants, it has remained largely mysterious what the origin of auxin response is, and what properties the ancestral, minimal auxin response system had. I will present

work from our team aimed at addressing these questions. I will summarize the analysis of the minimal auxin response system in the liverwort Marchantia polymorpha. Furthermore, I will report on a potentially ancient auxin response system, shared between land plants and algal sisters, that likely predates the well-known transcriptional auxin pathway. This system prominently involves rapid protein phosphorylation, and links auxin perception to rapid changes in cellular physiology, and reveals a potential ancestral function of auxin in the green kingdom.

References

Hernandez-Garcia, J., Carrillo Carrasco, V.P., Rienstra, J., Tanaka, K., de Roij, M., Dipp-Alvarez, M., Freire Rios, A., Crespo, I., Boer, D.R., van den Berg, W.A.M., Lindhoud, S., and Weijers, D. (2024). Evolutionary origins and diversification of Auxin Response Factors. Nature Communications, in press. [BioRXiv 2024.08.14.607941]

Kuhn, A., Roosjen, M., Mutte, S., Dubey, S.M., Carrillo Carrasco, V.P., Monzer, A., Kohchi, T., Nishihama, R., Fendrych, M., Sprakel, J., Friml, J. and Weijers, D. (2023). RAF-like protein kinases mediates a deeply conserved, rapid auxin response. Cell 187, 130-148.

Carrillo Carrasco, V.P., Hernandez Garcia, J., Mutte, S.K., and Weijers, D. (2023). The birth of a giant: evolutionary insights into the origin of auxin responses in plants. EMBO J. 42, e113018.