A Fruit Ripening Mystery

Ethylene is a simple plant hormone with a complex job. It tells flowers when to fade, fruits when to ripen, and leaves when to fall. Thanks to HHMI-GBMF investigator Joseph Ecker, scientists are one step closer to understanding the intricate events that ethylene puts into motion to do one of these tasks.

Scientists are sure about two things regarding the ethylene pathway and fruit ripening. The first is that ethylene binds to a receptor that activates a molecule called EIN2 on the surface of the cell’s endoplasmic reticulum. The second is that ethylene regulates transcription factors in the nucleus. But how the first event is related to the second was a mystery.

Ecker, at the Salk Institute for Biological Studies, discovered that the missing link is none other than EIN2. As he reported October 19, 2012, in Science, ethylene causes part of EIN2 to split off and travel to the nucleus, where it can interact with transcription factors.

This discovery could lead to new ways to thwart fruit spoilage. However, because ethylene also helps plants fight off pathogens, turning off the entire ethylene pathway is not an option. Ecker’s next task is to figure out which genes are affected by EIN2 in the nucleus. Then, rather than destroy the pathway altogether, scientists can selectively regulate the genes under ethylene’s control.

Scientist Profile

Salk Institute for Biological Studies
Molecular Biology, Plant Biology

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