Regulation of Brassinosteroid Homeostasis

Le séminaire aura lieu le 21 janvier dans la salle Lynn Margulis et sur Zoom.
https://inrae-fr.zoom.us/j/94788030079?pwd=cXXZouguT5bWAv10E44nCty19opaD2.1 

Abstract

Brassinosteroids are steroidal phytohormones essential for plant growth, development, and adaptation to environmental stresses. They act in a dose-dependent manner and do not travel over long distances. Therefore, maintaining brassinosteroid homeostasis is critical for their proper function. Due to their limited mobility, it was assumed that brassinosteroid signalling is primarily regulated by biosynthesis repression through a feedback loop. 

In the Arabidopsis thaliana root, brassinosteroid biosynthesis is restricted to the elongation zone, where it overlaps with brassinosteroid signalling maxima. However, in the dividing cells of the root apical meristem, a negative feedback loop maintains low but sufficient brassinosteroid activity. Expression pattern analysis of all known brassinosteroid biosynthetic enzymes has revealed that not all cells in the meristem possess the full biosynthetic machinery, and that the completion of biosynthesis relies on the cell-to-cell movement of hormone precursors.

In this talk, I will highlight the contribution of short-distance transport to the regulation of brassinosteroid homeostasis, as well as a recently uncovered polarity-guided mechanism that bypasses the negative feedback loop in dividing cells to ensure optimal root growth.

References

Vukašinović N, Hsu C W et al 2025. Cell S0092-8674(25)00196-5.
Ying W, Wang Y, Wei H, Luo Y et al 2024. Science 383: eadj4591.
Wang Y et al 2023. Nature Chemical Biology 19:1331-1341.
Vukašinović N, Wang Y et al 2021. Nature Plants 10: 1052.

Contact

Grégory Vert : gregory.vert@univ-tlse3.fr