Shedding light on plant development: light signalling in the model plant Arabidopsis thaliana

Light is one of the most important factors regulating plant growth and development. Depending on the availability of light, seedlings undergo two different developmental programs namely photomorphogenesis in the presence of light, and skotomorphogenesis in the absence of light. In the model plant Arabidopsis thaliana mutants in light signalling path ways have been identified that misregulate this response. The mechanisms behind light and dark growth have been studied extensively and recent studies have revealed how light signals are perceived and transmitted to downstream components. This review provides insight into light-perceiving photoreceptors and other positive and negative regulators of light signalling as well as interactions between these components. Genetic and biochemical evidence for the basis of light signalling mechanisms are discussed as well as the importance of light signalling in plant development.