Rice tiller angle mediated by the LAZY1-dependent asymmetric distribution of auxin

The angle at which leaves extend are held in a rice plant (tiller angle) affects the plant’s ability to intercept light and therefore potential yield. Genetic studies have identified a few genes involved in tiller angle, including the LAZY1 gene that encodes a protein involved in auxin transport. To identify other genes involved in this process, Zhang, Yu and Yu et al. looked at gene expression as rice seedlings responded to gravistimulation after being rotated 90°. The authors identified a HSFA2D, an upstream-acting transcription factor which when knocked out led to increased tiller angles, and two transcription factors (WOX6 and WOX11) that act redundantly downstream of auxin. As the authors summarize, “Collectively these approaches will identify genes to improve grain yields by facilitating the optimization of plant architecture”. (Summary by Mary Williams) Plant Cell10.1105/tpc.18.00063