Light control of Arabidopsis developmental pattern.

Abstract

As sessile organisms, higher plants are characterized by a high degree of developmental pattern plasticity in response to environmental signals, and in many cases respond to the changing environment by tailoring their developmental patterns in a way that maximizes their chances of survival and reproduction. Given the importance of photosynthesis to plant survival, light signals are arguably among the most important environmental cues to plant development. Genetic analysis of the light control of the Arabidopsis seedling development pattern has revealed that the pleiotropic COP/DET/FUS genes play a key role in integrating light signals and modulating developmental pattern formation. Recent studies support a working model in which COP1 act within the nucleus to sequester and inactivate transcription factors in darkness, while light abrogates this association by modulating COP1 nuclear abundance. This results in activation of the transcription factors and expression of genes responsible for photomorphogenic development. The other pleiotropic COP/DET/FUS proteins act to maintain the proper nuclear localization or retention of COP1 in darkness.