Researchers working with thale cress identified a protein called GATA25 that turns on TCP4, a gene regulator driving cell elongation, but only in the light. In darkness, a second protein, COP1, appears to break GATA25 down, keeping the growth signal switched off until light returns.
Plants cannot move, so timing their growth shapes how they adapt to changing conditions. This study names the working parts — GATA25, TCP4, and COP1 — of the switch that lets a seedling stretch in step with day and night. It fills a stated gap: how light signals reach the genes that control elongation.
✦ A plant reads the light before it grows — gene by gene, day by day.