Evolutionary and Developmental Mechanisms of Embryo Dormancy in Rice

South Dakota State University, Brookings SD

Investigators

Abstract

Name: Xing-You Gu Proposal number: IOS-1021382 Title of the proposal: Evolutionary and developmental mechanisms of embryo dormancy in rice Domestication of cereal crops from wild relatives has reduced seed dormancy, which can be imposed by inherent constraints within the embryo (embryo dormancy) or by restrictive tissues covering the embryo (coat-imposed dormancy). A small region of the genome designated as qSD12 has been isolated from weedy rice and is known to contain one or more genes that control embryo dormancy. Map-based cloning has identified two candidate genes for qSD12. The project aims to determine the function, origin, differentiation, and distribution of the candidates and to identify qSD12 downstream gene networks that regulate the development of embryo dormancy in the rice model system. Isogenic lines for the candidate genes and several approaches, such as complementation, haplotype, and transcriptomic analyses, will be used to achieve these objectives. The project is expected to assign one or two of the candidate genes to the function of embryo dormancy, reveal whether the dormancy gene(s) differentiated before or after the rice domestication, whether cultivated rice species and subspecies originated from different functional mutations, and provide direct knowledge of molecular and physiological pathways through which the naturally occurring gene regulates embryo dormancy. The broader impacts of the project include: 1) practical training for graduate, undergraduate, and high school students and teachers in biology and agricultural programs; and 2) interdisciplinary collaborations to use the dormancy gene for breeding varieties resistant to pre-harvest sprouting and to test the hypothesis that orthologous genes regulate dormancy and germination in other grasses.