Leaf growth regulators discovered
Establishing the top and bottom side of leaves is important for plants to take full advantage of sunlight and other environmental conditions. Recent research has identified two genes — REVOLUTA (REV) and KANADI1 (KAN1) — as potential master regulators of this phenomenon. The EU-funded EVOSIGNAL project aimed to better understand how REV and KAN1 interact to establish the orientation of new leaves, known as the ad/abaxial axis. The project focussed on genes that are under direct control of REV and KAN1. EVOSIGNAL created mutated Arabidopsis thaliana and Cardamine hirsuta plants that allowed researchers to study the effects of these two master regulator genes. They discovered a large number of genes controlled by KAN1 and REV. Notably, many genes were under opposed control of both — one represses gene activity while the other promotes activity of the same gene. Overall, researchers showed that KAN1 and REV work together to create gene expression gradients from the top to the bottom side of the leaf. This is a common genetic mechanism that controls tissue development in all higher organisms. In addition, the work of EVOSIGNAL revealed that REV and KAN1 also function in adaptive developmental programs. Here REV promoted shade growth while KAN1 strongly repressed cell growth in shade. Future directions of this research will be to study how REV and KAN1 influence physiological plant processes.
Keywords
Leaf growth, REVOLUTA, KANADI1, new leaves, Arabidopsis thaliana
