Introduction on seed dormancy and germination

Principle investigator: Leónie Bentsink

Leónie Bentsink, Phuong Nguyen, Hanzi He, Marieke van Bolderen-Veldkamp and Bas Dekkers

Seeds and proper control of seed germination are very important since seeds are the link between two successive generations of plants. Seeds allow the plant to survive periods in which conditions are not optimal to complete it’s life cycle and allow it to be transported to new locations as well. The timing of germination is of extreme importance, when a seeds germinates at moments or under conditions that the plant cannot complete its life cycle it will die. This timing of germination is controlled by seed dormancy.

Seed dormancy is an important adaptive trait that together with flowering time is a primary component of the different life history strategies of plants. Dormancy can be considered as a mechanism where growth and development is arrested, despite the presence of favourable environmental conditions for growth and development. The depth of dormancy is strongly affected by the genetic backgrounds as well environmental conditions. These environmental factors can act during seed development on the mother plant, during seed storage (after-ripening) and in imbibed (wet) mature seeds. We are interested to identify genes and pathways that control seed dormancy in nature. Therefore we have performed quantitative trait loci (QTL) analyses in six recombinant inbred line populations of Arabidopsis thaliana. Eleven QTL (delay of germination; DOG) have been identified and the effect of these loci on seed dormancy has been validated be means of near isogenic lines (NILs). These NILs have been used to identify the genes underlying the QTL and to identify downstream genes. This has been done using fine-mapping and transcriptomics analyses. The first of these QTL, DOG1 (Bentsink et al., PNAS 2006) has been cloned and the cloning of DOG6 is on its way.