Abstract
Lateral root (LR) formation is essential for the construction of plant root system. Auxin promotes LR formation which is initiated from asymmetric cell division of the root pericycle cells in most dicots. In Arabidopsis, several Aux/IAAs and two Auxin Response Factors (ARF7 and ARF19) regulate LR formation through auxin-mediated gene expression. It has been shown that Lateral Organ Boundaries-domain 16/Asymmetric Leaves2-like 18 (LBD16/ASL18) and LBD29/ASL16 genes are responsible for LR formation as direct targets of ARF7/19 (Okushima et al., 2007). In addition to LBD16 and LBD29, the other three LBD/ASL members (LBD17, 18 and 33) expressed around LR initiation sites and no obvious phenotype was observed in the knockout mutant of LBD16. These observations suggested the functional redundancy of the auxin-inducible LBD/ASL members in LR formation. This study is concerned with the detailed expression analysis of LBD16 during LR initiation and phenotypic analysis of the dominant negative mutant of LBD16.
