ABSTRACT
Plants exploit phenotypic plasticity to adapt their growth and development to prevailing environmental conditions. Interpretation of light and temperature signals are aided by the circadian system which provides a temporal context. Phenotypic plasticity provides a selective and competitive advantage in nature but is obstructive during large-scale, intensive agricultural practices since economically important traits (including vegetative growth and flowering time) can widely vary depending on local environmental conditions. This prevents accurate prediction of harvesting times and produces a variable crop. We sought to restrict phenotypic plasticity and circadian regulation by manipulating signalling systems that govern plants' responses to environmental signals. Mathematical modelling of plant growth and development predicted reduced plant responses to changing environments when circadian and light signaling pathways were manipulated. We tested this hypothesis by utilising a constitutively-active allele of the plant photoreceptor phytochromeB, along with disruption of the circadian system via mutation of EARLY FLOWERING3. We found that these manipulations produced plants that were less responsive to light and temperature cues and which failed to anticipate dawn. These engineered plants have uniform vegetative growth and flowering time, demonstrating how phenotypic plasticity can be limited whilst maintaining plant productivity. This has significant implications for future agriculture in both open fields and controlled environments.
