How Plants Receive the Signal to Flower

Can You Hear Me Now?

A fundamental step in understanding how a signal works is identifying what specifically receives the signal.

The signal in question here is the flower-inducing hormone in plants called florigen, which has recently been identified in several plant species, including rice. (Please see this recent post for more background.)

In rice, florigen is likely a protein named Hd3a. (The name, by the way, comes from Heading date 3a, which was the name given to this gene originally identified by rice geneticists as playing a role in flowering.)

A receptor for Hd3a has been identified according to a report in the most recent issue of Nature magazine (see reference below).

Briefly, Hd3a proteins bind to 14-3-3 proteins (a type of regulatory molecule present in all eukaryotic cells) in the cytoplasm of cells located in the shoot apical meristem.

These Hd3a/14-3-3 units then apparently act like little car keys to turn on specific “bZip” transcription factors (TF) in the cell’s nucleus, which, in turn, activate genes involved in the very first steps of flowering.

Bottom Line: New scientific results indicate that 14-3-3 proteins act as intracellular receptors for florigen in shoot apical cells. This information may offer plant scientists new approaches to manipulate the onset of flowering in ornamental plants, crops, and trees.


Taoka, K-i., et al. (2011) “14-3-3 proteins act as intracellular receptors for rice Hd3a florigen.” Nature, Vol. 476, pp. 332–335. (Abstract) © 2008-2011 All Rights Reserved.

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