By mutating just two genes, researchers in Belgium have turned a slender annual plant (inset) into a bushy, woody perennial (main picture).
Perennials have repeatedly evolved from annuals, but genetic changes that can cause this switch had not been identified. Siegbert Melzer of Ghent University and his colleagues studied Arabidopsis thaliana with mutations in soc1 and ful, which both regulate when the species flowers.
Mutants with dysfunctional forms of both genes formed woody stems and structures resembling dormant buds. These buds awakened periodically, producing several waves of growth and a longer lifespan.