From the end to the start : genetic and physiological aspects of the lifespan of seeds

Abstract

Seed dormancy and longevity contribute to seed quality and together define the lifespan of the seed. Seeds are often stored dry in research and agriculture and during this dry storage, dormancy is released and ultimately the seeds deteriorate (up to 10 years for Arabidopsis). The mechanisms underlying seed lifespan and the interaction between dormancy and longevity are not fully understood. First, a new method (elevated partial pressure of oxygen, EPPO) was developed to be able to mimic and accelerate the entire seed lifespan. With this method, quantitative trait loci (QTL) mapping could be performed and candidate genes underlying two longevity QTL have been identified. A third longevity locus was identified by genome wide association studies, and knock-out lines for the candidate genes were analysed with the EPPO method. Dormancy was also studied in a field experiment. Transcriptome analysis was performed on seeds at different stages during dormancy cycling to gain more insight into the molecular mechanisms. The transitions between dormancy levels during cycling were found to be accompanied by large changes in the transcriptome. The genes encoding for the translation machinery are upregulated in non-dormant seeds in the soil, indicating that these seeds are prepared for rapid germination.