NSF Award
2425472
Cereals, such as rice, maize, wheat, and barley, are the most important caloric food sources worldwide. In cereal seeds, two diametrically opposed processes occur in close proximity: ethylene-induced programmed cell death in the starchy endosperm and the maintenance of living cells in the adjacent embryo. The gaseous plant hormone ethylene readily diffuses across cells and tissues, and how the embryo is protected against ethylene-induced programmed cell death has not been determined. The goal of this project is to uncover fundamental mechanisms underlying how the seed embryo is protected from programmed cell death during development using rice as an experimental system. In addition to elucidating a critical developmental mechanism, results from the study will provide avenues by which to modify crops to protect them against a changing climate. The proposed research will provide excellent training opportunities for graduate students and postdoctoral fellows. The principal investigator will participate in public forums to raise science awareness and, through a local partnership, implement an art-science program for pre-teens aimed at developing education and science awareness through a hands-on active learning experience.<br/><br/><br/>The goal of this project is to elucidate the role of a clade of ethylene receptors that are hypothesized to modulate ethylene sensitivity on the process of programmed cell death during rice seed development. The first objective is to determine the temporal and spatial pattern of receptor expression in the rice seed, and to determine how this correlates with ethylene activity and programmed cell death. The second objective is to functionally characterize receptor roles in the rice seed by employing CRISPR/Cas9-generated loss-of-function mutations. Mutants will be evaluated for physiological and molecular effects in the embryo and endosperm, along with the effects of ethylene, drought stress, and heat stress, which are predicted to increase sensitivity of the mutant seed to programmed cell death. As a complement to the loss-of-function approach, in the third objective the effects of ectopic receptor overexpression will be evaluated as well as the ability of different receptor variants to rescue mutant seed phenotypes. Additionally, to gain an evolutionary perspective on the role of ethylene in seed development, distantly related grasses to the cereals will be evaluated for how their complement of ethylene receptors correlate with sensitivity to programmed cell death.<br/><br/>This award was co-funded by the Physiological Mechanisms and Biomechanics and the Plant, Fungal, and Microbial Developmental Mechanisms Programs in BIO-IOS.<br/><br/>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.
