Plant mothers talk to their embryos through hormone signals

Development in the womb depends on a whole host of factors, not the least of which is the nourishing network of signals between mother and embryo that cue healthy growth.

In humans and animals, the underlying maternal process in embryo and later fetal development are well understood and defined, however this connection in plants has previously been a puzzle to scientists.

For plants, signals from the mother are vital for the embryo just as in humans, and now a new study has identified the origin of maternal plant signals that influence embryo growth.

Plant scientists from the Institute of Science and Technology Austria conducted the research which was published in the journal Nature Plants.

The results show that plant mothers “talk” to their embryos via a hormone called auxin and this drives healthy embryo development.

Auxin is so crucial to plant growth that previous research has found that it plays a role in the development of flower formation and seedling growth.

“Plant scientists have been trying to figure out the nature of the signal between mother and embryo for decades,” said Jiri Friml, a corresponding author of the study. “We show that the mother is the source of auxin which regulates early embryo development.”

The researchers visualized the biosynthesis of the plant and the embryo’s response to auxin and found that after fertilization, the maternal tissue around the plant embryo in the seed produces more auxin.

In order to show that it was maternal auxin that impacted embryo development the researchers conducted an experiment and in some plants, auxin was only produced by the embryo and not the maternal tissue.

When the auxin production was interrupted, the researchers observed embryo development defects even though auxin was still present in the embryo.

The study identifies a key maternal signal that influences embryo development, however, the researchers found there were still unknown factors at work, calling for further research.

“When we stop the supply of auxin from the mother to the embryo, the embryo grows abnormally, but it still manages to develop somehow,” said Friml. “This means that there must be another, auxin-independent, signal.”

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By Kay Vandette, Earth.com Staff Writer

Image Credit: Chulmin Park