Abstract
Root structure is defined by a combination of some parameters on several component roots, such as their length, number and configuration. Such root structure determines the overall function of the root system. Generally, the root system of most of the dicot plants develops from the radicle, while monocot plants have a so-called fibrous root system which is characterized by many crown (adventitious) roots. However, the mechanism of crown root formation has not yet been clarified. To investigate the genetic mechanism regulating crown root formation, we identified a recessive rice mutant without formation of crown roots, crl1 (crown rootless1). We isolated CRL1 by positional cloning, and found that CRL1 encoded a protein homologous to a Arabidopsis LATERAL ORGAN BOUNDARIES (LOB)-domain protein. In this symposium, we will review the root system functions in rice and other grasses and present some results on the CRL1 gene.
