Plants might remember with prions

There’s no known mad plant disease. But 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 that shift in form and function. Now a protein called luminidependens, which is connected with flowering, shows signs of these shapeshifter and template powers, researchers report April 25 in the Proceedings of the National Academy of Sciences.

Study coauthor Susan Lindquist of the Whitehead Institute for Biomedical Research in Cambridge, Mass., and her colleagues devised a way to test 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 floral tasks as keeping track of a decent winter’s chill.