From Stress to Success: Harnessing Pre- and Post-Harvest Seed Priming

The increasing climate variability, together with more frequent environmental stresses, threatens crop performance, making it imperative to address harsh challenges in the coming decades to ensure stable yields. In this context, crop stress resilience is a key solution that can be achieved via genetic improvement or via setting the conditions for the plants to be primed (or prepared) to face upcoming stresses. The latter option emerges as a groundbreaking solution that encompasses different approaches according to the timing of the priming process. As crop establishment is the first yield-determining stage, building seed resilience to promote germination under stressful conditions and seedling vigor is crucial. So far, the seed industry has mainly focused on developing seed priming protocols, which correspond to a wide range of post-harvest processes aimed at optimizing germination and vigor. Hence, these seed priming treatments are applied to the harvested seeds before sowing. Another approach relies on stress-induced priming effects while the seeds are on the mother plant. These stress-triggered changes acquired within the mother plant require maintenance and reactivation in the mature seeds upon germination/early growth. Both approaches, that is, pre- and post-harvest seed priming, depend on diverse signals and regulatory processes (e.g., epigenetic, transcriptomic and metabolomic ones). In this review, we will discuss pre-/post-harvest seed priming approaches to decipher the common and specific underlying mechanisms and to provide new directions for the seed sector.