A team of plant physiologists, led by Dr. Guillaume Née and Prof. Iris Finkemeier at the University of Münster, has uncovered the molecular basis behind the balance between seed dormancy and stress resistance.
The timing of seed germination is crucial for a plant’s survival, determining its growth potential. Seed dormancy serves as a natural barrier to germination, triggered by environmental factors like prolonged cold or dry storage. This mechanism ensures that seeds germinate at the right time, contributing to ecosystem stability by maintaining a pool of dormant seeds that can withstand adverse conditions. Despite its importance, the molecular processes involved in breaking seed dormancy have remained unclear, according to a press release.
Now, the research team from the Institute of Plant Biology and Biotechnology has revealed how a key evolutionary adaptation allows seeds to regulate germination precisely, while also maintaining their resistance to environmental stresses. Their findings, published in Science Advances, provide new insights into the complex mechanisms behind seed dormancy and stress tolerance.
Guillaume Née, a junior research group leader in Prof. Iris Finkemeier’s team, is exploring how seeds balance stress responses with the gradual release from dormancy. Both processes are regulated by the plant hormone abscisic acid, which is crucial for preventing germination and triggering stress responses, such as drought resistance. This study uncovers a previously unknown molecular signaling pathway that governs abscisic acid responses independently from the hormone’s main signaling mechanisms.
This independent system, which functions solely in dormant seeds, is regulated by the Delay of Germination 1 (DOG1) protein. DOG1 acts as a molecular “fuse,” preventing the suppression of abscisic acid responses during seed imbibition, thus inhibiting germination. Over time, or in response to environmental signals, DOG1 activity gradually diminishes, leading to the cessation of abscisic acid responses and the release of the seed’s germinative potential. Importantly, since this pathway operates outside the core abscisic acid signaling system, the hormone’s role in stress responses remains unaffected, enabling seeds and seedlings to maintain stress tolerance even after dormancy ends.
The balance between seed dormancy and stress resistance is a key evolutionary adaptation that has helped seed plants thrive globally and plays an important role in agriculture. Germination characteristics are critical for food security, influencing seedling emergence, as well as industrial processes such as malting (the controlled germination of brewing grains) and baking.
“Germination has been a selected trait since the beginning of plant domestication,” points out Née. “For successful breeding programmes, it is important to understand the evolutionary, genetic and molecular factors that control seed germination.” This knowledge makes it possible to find solutions inspired by nature to optimise germination characteristics.
In addition to the team from Münster, researchers from the Max Planck Institute for Plant Breeding Research in Cologne and the University of Ghana also contributed to the study. The research team explored seed dormancy regulation using thale cress (*Arabidopsis thaliana*) as a model, employing a range of methods from proteomics, molecular and cell biology, physiology, biochemistry, and genetics.
The study was financially supported by the German Research Foundation, the Max Planck Society, the German Academic Scholarship Foundation, and the German Academic Exchange Service (DAAD).
