Seed priming is widely used in commercial seed production and its main function is to accelerate and synchronize seed germination. The priming technique consists of a series of treatments with controlled amounts of water or osmotic solutions that allow the activation of the germination metabolism without allowing protrusion of the seed coat. However, primed seeds show reduced longevity, causing problems for their storage. Treatments like heat shock have been shown to improve the longevity of primed seeds. Enhanced longevity of primed seeds has been observed after exposure to 37°C heat for as little as 2 hours. However, little is known about the effects of this kind of heat shock treatment at the molecular level or what the exact mechanisms that govern the enhancement of longevity are.
In their new study published in AoBP, Batista et al. aimed to investigate the effect of heat shock treatment on the longevity of primed tomato (Solanum lycopersicum) seeds at the physiological and transcriptome levels. Their results confirm that heat shocked seeds have enhanced longevity compared to those not treated with heat shock. In addition, these seeds showed an increase in mRNA levels of HEAT SHOCK FACTOR-like and HEAT SHOCK PROTEIN-like chaperone genes, suggesting that the proteins coded by these transcripts are involved in the enhancement of seed longevity of primed tomato seeds. This study expands our understanding of the molecular mechanisms involved in seed longevity and highlights that these processes are associated with molecules commonly associated with response to stress. These findings could lead to commercially produced seeds with longer shelf life and increased vigour.