Timing of Environmental Signalling
We live in a world that spins around its axis with a period of ~24 h. This has created rhythmic changes in the environment, such as the day-night cycle, or changes in temperature, humidity, and UV light. In turn, this has shaped the evolution of most organisms that live on earth and led them toevolve an internal time-keeping mechanism to help them predict these changes: the circadian clock.
Plants, such as Arabidopsis thaliana, possess a circadian clock, and most of its molecular components have been established. Moreover, the circadian clock helps plants optimise their fitness (photosynthesis, biomass, yield) when they are in tune with nature. This makes the molecular clockwork and its outputs interesting targets of research to help us understand how daily changes in the environment are coupled to changes in internal molecular and physiological variables and has profound implications for crop breeding/improvement efforts.
Another remarkable characteristic of plants is that they have inherent plasticity. Their general body plan is genetically encoded, but plant architecture can be modified to adjust to the environment that surrounds it. In this sense, environmental signals have a profound effect on plant growth and development, ultimately affecting a plant’s fitness, disease resistance and productivity. An important feature of this process is the “gating” of signals through the plant’s internal clock, which results in the rhythmical inhibition of the activity of environmental inputs to ensure proper temporal coordination of regulatory processes. Besides its obvious relevance for crop improvement, research into time-of-day dependent modulation of plant plasticity will advance understanding of this fundamental property that underlies the extraordinary evolutionary success of plants.