Pleiotropic effects of ZmLAZY1 on the auxin-mediated responses to gravity and light in maize shoot and inflorescences.

Auxin has been found to control both gravitropism and inflorescence development in plant. Auxin transport has also been demonstrated to be responsible for tropism. Maize, a key agricultural crop, has distinct male (tassel) and female (ear) inflorescence, and this morphogenesis depends on auxin maximum and gradient. The classic maize mutant lazy plant1 (la1) has defective gravitropic response. The mechanism underlining maize gravitropism remains unclear. Recently, we isolated the ZmLA1 gene by map-based cloning, and our findings suggest that ZmLA1 might mediate the crosstalk between shoot gravitropism and inflorescence development by regulating auxin transport, auxin signaling, and auxin-mediated light response in maize. Here, we propose a model describing the ZmLA1-mediated complex interactions among auxin, gravity, light, and inflorescent development.