Shoot and root branch growth angle control—the wonderfulness of lateralness

The overall shape of plants, the space they occupy above and below ground, is determined principally by the number, length, and angle of their lateral branches. The function of these shoot and root branches is to hold leaves and other organs to the sun, and below ground, to provide anchorage and facilitate the uptake of water and nutrients. While in some respects lateral roots and shoots can be considered mere iterations of the primary root-shoot axis, in others there are fundamental differences in their biology, perhaps most conspicuously in the regulation their angle of growth. Here we discuss recent advances in the understanding of the control of branch growth angle, one of the most important but least understood components of the wonderful diversity of plant form observed throughout nature.