Genetic complexity at root of plant life cycle

For the first time, the genetic wiring that helps a seed decide when to germinate has been revealed – this mechanism also tells the plant when to flower say scientists who have untangled the complex web of genetic interactions in a model plant.

Seeds in soil use a range of environmental cues – temperature, light, moisture and nutrients – when deciding whether to germinate or remain dormant. Evolution has genetically wired seeds in a complex way to ensure the decision to germinate is made at the optimum moment to ensure survival.

Researchers from the University of Nottingham compiled publically available gene expression data and used statistical analysis to uncover these genetic interactions in Arabidopsis thaliana or thale cress.

The resulting gene network – SeedNet – highlighted just how little scientists know about the regulation of seed germination, but has been able to predict novel regulators of the process with remarkable accuracy.

“To our surprise, the seed network demonstrated that genetic factors controlling seed germination were the same as those controlling the other irreversible decision in the life cycle of plants; the decision to start flowering,” said project leader, Dr George Basel. “The induction of flowering, like germination, is highly responsive to the environment.”

Furthermore, SeedNet discovered the same genes that leaves and roots use to respond to stress are used by seeds to stop their germination. Since seeds evolved after plants developed the ability to withstand environmental stress, researchers believe that plants have adapted existing genes to fulfil a different role.

It is hoped that the work could lead to identifying important factors controlling stress response in seeds and the plant itself, and could contribute to developing new crop species which are resistant to climate change and help secure future food supplies.