Unravelling the dynamics of seed-stored mRNAs during seed priming

Seed priming is a pre-sowing treatment that enables more efficient and uniform seed germination; however, it negatively affects seed longevity. In this work, the mRNA dynamics underlying a hydropriming treatment have been investigated. Polysome profiling was performed on seeds during different stages of hydropriming. Ribosome nascent chain complex sequencing (RNC-seq) elucidated transcriptomic and translatomic changes during the priming treatment. In contrast to mature dry seeds, hydroprimed seeds contain more mRNA-ribosome complexes, suggesting that the mRNAs that need to be translated during germination are already associated with ribosomes in the primed seeds, leading to a quicker restart of translation and thus faster germination upon re-imbibition. As a result of priming, seeds lose part of their stress-related transcriptome. This work highlights genes that might play a role in increasing the rate of germination after priming.