Seed dormancy is a key adaptive trait of both ecological and agriculture significance

The Department of Agriculture National Institute of Food and Agriculture awarded South Dakota State University $644,000 on September 15, 2026, under the Agriculture and Food Research Initiative (AFRI) Foundational and Applied Science Program to conduct molecular genetics research on seed dormancy and germination in rice.

The project identifies regulatory roles of the gibberellin signaling pathway in seed dormancy and germination by evaluating genic effects of key genes (SLR1, GID1, GID2) on embryo dormancy and germination, examining genetic and molecular interactions between SD7-2 and SLR1, and using transcriptomic analysis to identify genes regulated by SLR1 in germinating seed embryos. The research assembles natural and induced variants at multiple loci into uniform genetic backgrounds to measure additive and dominance effects and digenic epistasis on seed dormancy degree and germination velocity, confirms protein-level interactions, and screens differentially expressed genes for candidate mediators between regulatory pathways. Results will advance understanding of how the gibberellin signaling pathway is regulated and how naturally occurring dormancy genes influence germinability, yielding candidate genes for agricultural application.

Performance occurs at South Dakota State University in Brookings, South Dakota, with a period of performance from September 15, 2026, through September 14, 2029. AFRI supports research, education, extension, and integrated grants to improve rural economies, alleviate pest and disease impacts, increase agricultural profitability, and enhance food safety and nutrition across six farm bill priority areas including plant health and production.

This project aims to identify regulatory roles of gibberellin (GA) signaling (GS) pathway in seed dormancy (SD) and germination, two sequentially related physiological processes. Bioactive gas promote germination through GS, and the GS core elements are encoded by the single-copy genes SLR1, GID1 and GID2 in rice. The SD gene SD7-2 encodes a protein kinase likely acting as an upstream regulator of SLR1, and both SD12A and c genes encode bhlh transcription factors presumably regulated by SLR1. The objectives of this project are to identify: 1) genic (additive and dominance) effects of SLR1/SLR1-1, GID1/GID1-3 and GID2/GID2-1 on embryo dormancy and germination; 2) genetic and molecular interactions between SD7-2 and SLR1; and 3) genes and gene networks that are regulated by SLR1 in embryos of germinating seeds. Induced mutants and a seed-based genetic approach have been developed to evaluate additive and dominance effects of the GS loci. Natural or induced variants at the SLR1, SD7-2, SD12A and SD12C loci will be assembled into the same genetic background to evaluate their main (additive & dominance) effects and effects of digenic epistasis between the SLR1 and the SD7-2, SD12A or SD12C locus on the degree of SD and germination velocity. The SLR1-SD7-2 interaction will be confirmed at the protein level. Transcriptomic analysis is being used to identify differentially expressed genes (degs) between four SLR1/SLR1-1 genotypes in embryos of germinating seeds. The degs will be confirmed to infer their cellular/molecular functions during germination and to screen for candidate mediators between SLR1 and SD12S. This research will advance our knowledge of GA signaling and molecular genetics of seed dormancy by answering to how the GA signaling pathway is regulated and how the naturally occurring SD genes are regulated to influence germinability and will also provide candidate genes and isogenic lines for genetic improvement or modifications of cereal crops to solve germination-related problems, such as pre-harvest sprouting, inadequate germination of commercial seeds.