Organ-specific COP1 control of BES1 stability adjusts plant growth patterns under shade or warmth

Dev Cell. 2022 Aug 22;57(16):2009-2025.e6. doi: 10.1016/j.devcel.2022.07.003. Epub 2022 Jul 27.

Abstract

Under adverse conditions such as shade or elevated temperatures, cotyledon expansion is reduced and hypocotyl growth is promoted to optimize plant architecture. The mechanisms underlying the repression of cotyledon cell expansion remain unknown. Here, we report that the nuclear abundance of the BES1 transcription factor decreased in the cotyledons and increased in the hypocotyl in Arabidopsis thaliana under shade or warmth. Brassinosteroid levels did not follow the same trend. PIF4 and COP1 increased their nuclear abundance in both organs under shade or warmth. PIF4 directly bound the BES1 promoter to enhance its activity but indirectly reduced BES1 expression. COP1 physically interacted with the BES1 protein, promoting its proteasome degradation in the cotyledons. COP1 had the opposite effect in the hypocotyl, demonstrating organ-specific regulatory networks. Our work indicates that shade or warmth reduces BES1 activity by transcriptional and post-translational regulation to inhibit cotyledon cell expansion.

Keywords: COP1; PIF4; brassinosteroids; growth (plants); plant hormones; shade avoidance; thermomorphogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis Proteins* / metabolism
  • Arabidopsis* / metabolism
  • Brassinosteroids / metabolism
  • DNA-Binding Proteins / metabolism
  • Gene Expression Regulation, Plant
  • Hypocotyl / metabolism

Substances

  • Arabidopsis Proteins
  • BES1 protein, Arabidopsis
  • Brassinosteroids
  • DNA-Binding Proteins