Signal transduction during light-quality acclimation in cyanobacteria: a model system for understanding phytochrome-response pathways in prokaryotes
Abstract
The colorful process of complementary chromatic adaptation (CCA), in which cyanobacteria dramatically alter their pigmentation in response to ambient light color changes, has intrigued scientists for more than a century. Over the past four decades, intensive research on the model organism Fremyella diplosiphon has revealed many details of the photobiology and molecular biology of this process, which includes restructuring of these organism's photosynthetic light-harvesting antennae, called phycobilisomes. This restructuring involves changes in transcription of genes encoding phycobilisome components. These genes have been cloned and their patterns of light-responsive expression characterized. In the past ten years, attention has focused on the signal transduction mechanism(s) through which cyanobacteria sense and respond to changes in ambient light color. Genetic approaches led to the isolation of signal transduction components that control light-color responses in F. diplosiphon. Several of these appear to be within a complex phosphorelay that is in part controlled by a photoreceptor called RcaE, the founding member of a large, novel class of prokaryotic photoreceptors with similarity to both plant phytochrome photoreceptors and sensor
- This article is part of the themed collection: Biological photosensors