Plants evolved a specific subnuclear "switch" that completely flips how they respond to their most important growth hormone.

Auxin is the hormone that tells a plant how to grow, but the way it works has been a mystery for decades. Researchers found that the Mediator complex clusters into specific groups inside the nucleus to turn repressor genes into activators. This tiny biochemical reorganization is what allows a plant to suddenly change its growth strategy in response to its environment. It is the first time the exact mechanism for this fundamental transition has been identified at the subnuclear level. This discovery explains how plants manage such complex development with a relatively simple set of hormones.