Brachypodium as a model to understand the genetic regulation of seed dormancy in temperate grasses

Seed germination initiates the plant life cycle. In the wild this needs to be aligned with optimal environmental conditions. In the field this should not occur prematurely while still attached to the plant, but uniformly after sowing. Germination is regulated through an adaptive postponing process call seed dormancy. While we know that a conserved core mechanism controls dormancy, involving the hormonal balance between abscisic and gibberellic acid, the upstream pathways and the molecular mechanisms at play are not well understood. Yet the genetic regulation of seed dormancy in temperate grasses is highly relevant because they include the temperate cereal crops. These crops mostly lost dormancy through domestication and are not straightforward to use in genetic studies because of the complexity of their genomes. We therefore propose to study the genetics of seed dormancy in the temperate model grass Brachypodium for which accessions show strong dormancy and strong variation in dormancy. Specifically, we propose that two PhD students (1) characterise the transcriptome while dormancy is established or released, (2) order known genes into pathways through CRISPR genetic interaction mapping, (3) identify novel dormancy regulators through loss-of-dormancy and gain-of-dormancy EMS screens with subsequent next-generation mapping. Together, these approaches will provide basic knowledge about seed dormancy in temperate grasses and leads to controlling this trait in cerealcrops.

Keywords:seed dormancy, Brachypodium, pre-harvest sprouting, temperate cereals, wheat, barley

Disciplines:Crop science, Plant genetics