ERF50 controls the timing of seed germination through feedback regulation of pivotal genes.

Seed dormancy governs germination timing, with both evolutionary and applied consequences. Despite extensive studies on the hormonal and genetic control of these processes, molecular mechanisms directly linking them remain poorly understood.

The ability of a seed to germinate and establish a plant at the right time of year is of vital importance from an ecological and economic point of view. In most species, seeds are dormant when they have just developed in the mother plant, meaning they cannot germinate yet. This circumstance is advantageous since it allows a greater spatial range of dispersal and, therefore, reduces the probability that the mother plant and its seeds compete for the same resources; in addition, it prevents germination at times of the year that would be incompatible with the life cycle of the plant, for example during short periods of good weather in the middle of winter. Therefore, the ability of seeds to perceive the environmental signals associated to seasons allows them to gradually adjust their dormancy levels and their germination capacity. Previously, it had been determined that the DOG1 gene is essential for maintaining seed dormancy while the RGL2 protein (DELLA type) plays a very relevant role in blocking germination.In our recently published work we have discovered that the ERF50 gene represents a "molecular link" that connects both physiological processes. On the one hand, although DOG1 favors the increase in ERF50 levels, the latter acts as a direct repressor of the former. Furthermore, ERF50 activates genes that stimulate germination thanks to its ability to directly antagonize the role of RGL2 in this process. In summary, ERF50 acts as a leveler of both processes since its activity increases in conditions that negatively affect germination to avoid excessive dormancy. Similarly, ERF50 levels also decrease with reduced dormancy, which prevents excessive activation of germination.

In summary, thanks to the combined used of genetic, physiological and molecular approaches we have demonstrated that ERF50 has a key role in the control of seed dormancy and germination. Furthermore, ERF50 does not affect seed longevity (storage time without losing viability) and has great potential as a specific marker of germination timing and as biotechnological tool.

Original Paper: Carrera-Castaño, G., Mira, S., Fañanás-Pueyo, I., Sánchez-Montesino, R., Contreras, Á., Weiste, C., Dröge-Laser, W., Gómez, L., Oñate-Sánchez, L. 2024. Complex control of seed germination timing by ERF50 involves RGL2 antagonism and negative feedback regulation of DOG1. . DOI: 10.1111/nph.19681