Signalling network in plant responses to shade

CASAL, JORGE JOSÉ

Iguazú Falls

Congreso; Conferencia plenaria. International Plant Molecular Biology Congress; 2015

Plants are exposed to fluctuating degrees of shade by neighbours. Therefore, light levels can dynamically shift from excessive to limiting and vice versa. The perception of light signals by sensory photoreceptors helps plants to adjust to these changing conditions. A key pathway involves the reduction of phytochrome B activity by shade, the consequent promotion of PHYTOCHROME INTERACTING FACTOR (PIF) activity, the binding of PIFs to auxin synthesis genes leading enhanced auxin levels, and the promotion of stem growth to alleviate shade. Despite the significance of this short, simple pathway, many other genes are important for plant responses to shade. For instance, we will describe the wiring of CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) signaling to the PIF pathway. Multiple connections generate a complex network that we are beginning to understand in functional terms. We will show the importance of specific regulatory loops in the context of the environmental fluctuation that plants normally face.