Brassinosteroids regulate root growth by controlling reactive oxygen species homeostasis and dual effect on ethylene synthesis in Arabidopsis
Fig 10
Proposed model to explain how BR regulates root growth in A. thaliana.
BR inhibits ethylene synthesis by activating the transcription factors BZR1 and BES1 to repress the transcription of ACSs under low levels. While high levels of BR induce ethylene biosynthesis either through increasing the stability to ACSs or influencing auxin signaling regulated ethylene. At the same time, BR inhibits the synthesis of O2- via the peroxidase pathway, but not NADPH oxidase pathway, which serves to regulate the growth of the A. thaliana seedling root.