Prions may help plants remember

Prions — which show their dark side in mad cow disease — may occur in plants as a form of memory.

Prions are proteins that change shape and shift tasks, and then trigger other proteins to make the same change. Inheriting prions lets cells “remember” and replicate a shift in form and function. A protein called luminidependens, which is connected with flowering, shows signs of these shapeshifter powers, researchers report online April 25 in the Proceedings of the National Academy of Sciences.

Susan Lindquist of the Whitehead Institute for Biomedical Research in Cambridge, Mass., and colleagues tested plant proteins for prion power by swapping bits of them into yeast prions. Luminidependens, found in the common lab plant Arabidopsis thaliana, fit the criteria, and may be the first botanical protein shown to act like a prion. Prionlike memory might be useful in such tasks as keeping track of winter’s chill.