Circadian Clock Gating of the Shade Avoidance Response Optimises Plant Fitness

As arable land becomes scarcer and the human population continues to grow, we need to focus our efforts on increasing yield. The goal is to rethink agriculture to ensure food security. One way to do so is to lower yield loss due to light limitation by neighbouring shade or high-density planting.

Phytochrome (phy) photoreceptors play a critical role in plant survival under vegetation shade conditions, by initiating a switch to a shade avoidance response (SAR) growth strategy.

Although SAR reconfigures overall architecture for optimal light capture, it results in elongation of growth of stem-like tissue, at the expense of harvestable organs.

Central to this adaptive response is an interaction between the plant's internal circadian clock and the phy pathways which restricts or gates the response to dusk.

As the clock was previously shown to have a general role in optimising fitness, this proposal will establish whether circadian gating of SAR confers a fitness advantage and delineate the underlying molecular mechanisms that link the clock to altered leaf cellular responses under SAR.

Bioluminescence reporters, optogenetic tools and the PS-plant 3D imaging platform will enable the capture of dynamical data from molecular to whole plant levels.

Further, pennycress, a novel oilseed crop and a close relative of Arabidopsis will be developed as a model to facilitate the direct translation of novel findings in this proposal, to increase plant fitness and yield to this new crop species.