Viable seeds are not always able to germinate and can cycle between a dormant and a non-dormant state. Dormancy prevents germination during unfavourable seasons and has been selected against during domestication of crop species. In the model plant Arabidopsis, dormancy is induced during seed maturation and released by dry storage (after-ripening). The plant hormone abscisic acid has an essential role in the induction of dormancy, whereas gibberellins are required for germination. However, the molecular mechanisms that regulate dormancy downstream and in parallel with these hormones are poorly understood.
DELAY OF GERMINATION 1 (DOG1) has been identified as a major regulator of seed dormancy, which is conserved in the plant kingdom. Loss-of-function dog1 mutants are completely nondormant. The DOG1 gene encodes a protein with unknown function that accumulates during seed maturation and functions independent of plant hormones. The amount of DOG1 protein in freshly harvested seeds highly correlates with their dormancy level and the protein loses its function during dry storage of seeds. We will present our latest results about the function of DOG1 in seed dormancy and its possible regulation by after-ripening.