Involved in the control of root growth angle (PubMed:23913002). Involved in cell elongation in the root tip that causes asymmetric root growth and downward bending of the root in response to gravity (PubMed:23913002). Negatively regulated by auxin. Introducing DRO1 into a shallow-rooting rice cultivar enables the resulting line to avoid drought by increasing deep rooting, and to maintain high yield performance under drought conditions. IR64 cultivar shows shallow rooting in an upland field. Belongs to the LAZY family.