The karrikin signaling regulator SMAX1 controls <i>Lotus japonicus</i> root and root hair development by suppressing ethylene biosynthesis
Samy Carbonnel, Debatosh Das, Kartikye Varshney, Markus C. Kolodziej, José Antonio Villaécija‐Aguilar, Caroline Gutjahr
Abstract
Significance Plant seedlings depend on efficient development of roots and root hairs for anchorage to the ground and for rapidly reaching nutrients and water for survival and growth. We found that a negative regulator of a small-molecule signaling pathway called “karrikin signaling” plays an important role in regulating root growth of the legume Lotus japonicus . Mutants of this regulator called “SMAX1” have short primary roots and strongly elongated root hairs. This phenotype is caused by enhanced ethylene biosynthesis, which in the wild type is suppressed by SMAX1. Thus, karrikin signaling regulates ethylene biosynthesis to fine-tune root development.