Light control of plant development: A role of the ubiquitin/proteasome-mediated proteolysis

Abstract

The relationship between light environment and plant development is most dramatically illustrated by seedling development in Arabidopsis. Arabidopsis seedlings exhibit two different phenotypes: photomorphogenesis in the light and skotomorphogenesis (or etiolation) in darkness, respectively. Light-grown seedlings have short hypocotyls, and open and expanded cotyledons, while skotomorphogenic seedlings have long hypocotyls and apical hooks (closed and unexpanded cotyledons) (for review, see [von Arnim and Deng 1996]). Recently, a major regulatory switch for the light control of seedling development was shown to be the ubiquitin/proteasome-mediated degradation of photomorphogenesis-promoting transcription factors ([Osterlund et al 2000], [Seo et al 2003], [Saijo et al 2003]). The pleiotropic COP (constitutive photomorphogenic)/DET (de-etiolated)/FUS (fusca) genes were initially identified to encode negative regulators of photomorphogenesis by genetic analysis, and recently they have been shown to play important roles in the protein ubiquitination processes.This review briefly summarizes our current understanding of the role of the COP/DET/FUS proteins and the ubiquitin/proteasome-mediated proteolysis in the light control of Arabidopsis seedling development.