Unlike animals, plants do not have specific organs that can see or hear various environmental stimuli; nor can they move around to avoid adverse conditions. Although lacking a "brain", plants can successfully integrate internal and external cues, and make appropriate decisions about growth. For example, shade cast by neighboring vegetation leads to rapid shoot growth to better capture sunlight under sub-optimal light conditions. At the same time, this shade avoidance response (SAR) decreases plant productivity and overall performance as resources are diverted towards growth and extension of the shoot at the expense of the root. This project will use an integrated genetic, genomic, and biochemical approach to study the underlying mechanisms of shade avoidance that allow the aboveground shoot to communicate with the belowground root to reallocate resources and alter growth. Shade avoidance is a universal problem in many crop plants, and the findings generated in this project could help develop crops that resist increased plantation density without affecting yield to improve food security. In addition to providing research training opportunities for postdoctoral associates and high school students, the project will establish an educational outreach program with an elementary school in Long Island (NY) to provide an integrated hands-on class that informs about the impact of the environment and other factors on crop yield.
Roots and shoots live in different environments, yet the root knows when the shoot faces adverse environmental conditions. Shade avoidance response (SAR) triggered by the sub-optimal light environment from nearby vegetation leads to rapid growth of the stem and petioles to maximize light capture but at the expense of root growth. Surprisingly, not much is known about the mechanisms that affect root growth when the shoot detects changes in light conditions. Given the importance of the roots in the overall growth and productivity of plants, this project aims to understand the molecular and genetic mechanisms by which root growth is affected by vegetative shading. Recent results suggest that roots activate stress responses in the shade to slow down its growth by diverting resources to the shoot. The specific aims are to (1) generate a high-resolution spatiotemporal transcriptome map of the root in the shade to uncover tissue-specific programs that alters growth; (2) characterize WRKY transcription factors and their associated signaling that may be involved in activating stress responses in the roots; and (3) investigate the nature of the shoot to root signals using a forward genetic screen and other techniques. If successful, this project could identify new components and provide new insight into the process that can be used to design cell-type specific or synthetic networks to inactivate or activate root growth in economically important crop plants.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
