Newly discovered signalling pathway helps plants to precisely control seed germination

To germinate or not to germinate? With plants, choosing the right moment to start their life cycle determines their chances of growth. Seed dormancy is an inherent barrier to germination in response to environmental cues, such as prolonged cold exposure or dry storage over time. Its precise alleviation ensures that seedlings emerge in the appropriate season. This mechanism contributes to ecosystem stability by maintaining a reservoir of quiescent seeds in the soil for years, allowing them to survive adverse conditions unscathed. The molecular mechanisms that break seed dormancy are still poorly understood. A research team led by Dr Guillaume Née and Prof Iris Finkemeier from the Plant Physiology Group at the Institute of Plant Biology and Biotechnology at the University of Münster has now shown how a central evolutionary adaptation enables seeds to precisely regulate the time of germination. The seeds are able to germinate while tolerating environmental stress, i.e. maintain their resistance to adverse conditions. The study has been published in the journal Science Advances.

Guillaume Née, a junior research group leader in Prof Iris Finkemeier’s team, is investigating how seeds balance stress responses with the gradual release from dormancy, considering that both processes are modulated by the same plant hormone, namely abscisic acid. This hormone is essential for preventing germination and is known to elicit plant responses to various stresses, such as drought. This study reveals a previously unknown molecular signaling pathway that regulates abscisic acid responses independent of the hormone’s main signaling mechanisms. This autonomous system, which operates exclusively 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, thereby inhibiting germination. Over time in dry storage or in response to environmental cues, the activity of DOG1 gradually diminishes, leading to the termination of abscisic acid responses and the release of germinative capacity. However, since this module operates independently of the core abscisic acid signaling pathway, the hormone’s role in stress responses remains unaffected, allowing seeds and seedlings to retain their ability to respond to environmental stress even after dormancy is lifted.

The balance between seed dormancy and stress resistance is an essential evolutionary adaptation that has contributed to the global success of seed plants and is also important for agriculture. Germination characteristics are crucial for food security, influencing both seedling emergence in the field and industrial applications such as malting (i.e. the controlled germination of brewing grains) and baking. “Germination has been a selected trait since the beginning of plant domestication,” points out Guillaume 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 group from Münster, scientists from the Max Planck Institute for Plant Breeding Research in Cologne and the University of Ghana were also involved in the study. The research team investigated the control of seed dormancy using the example of thale cress (Arabidopsis thaliana) and combined methods from proteomics, molecular and cell biology, physiology, biochemistry and genetics.

The German Research Foundation, the Max Planck Society, the German Academic Scholarship Foundation and the German Academic Exchange Service (DAAD) supported the work financially.

 

Original publication

Krüger T. et al. (2025): DOG1 controls dormancy independently of ABA core signaling kinases regulation by preventing AFP dephosphorylation through AHG1. Science Advances Vol. 11, Issue 9; DOI: 10.1126/sciadv.adr8502

Further information

• Original publication in "Science Advances"
• AG Finkemeier/Plant Physiology