Abstract
Monocot plants produce numerous adventitious (crown) roots that are dominant in the root system of cereals. We previously reported characterization of a rice mutant defective in crown root formation, crown rootless1 (crl1) and isolation of CRL1 gene that encodes a positive regulator for crown root formation and is directly regulated by an ARF in the auxin signaling pathway. Recently, we also identified and characterized other crl mutants, crl4 and crl5, and isolated genes corresponding to these mutants. We found CRL4 gene regulates auxin polar transport and CRL5 is involved in the crown root initiation same as CRL1. The crl1crl5 double mutants showed additive phenotype of each single mutant, suggesting that these genes do not work in the same regulatory pathway of crown root formation. Here, we discuss about molecular mechanism of crown root formation by these CRL genes.
