Abstract
Auxin, a plant growth regulator, promotes lateral root (LR) formation in many plant species but the regulatory mechanism is not fully understood. We have studied molecular cascade regulating auxin-mediated LR formation using several Arabidopsis mutants defective in LR formation. We have shown that Auxin Response Factor 7 (ARF7) and ARF19 regulate LR formation via activation of Lateral Organ Boundaries domain 16/Asymmetric Leaves2-like 18 (LBD16/ASL18) and LBD29/ASL16, which are nuclear proteins (Okushima et al., 2007). Because these LBD/ASLs are thought to be transcriptional regulators, we tried to identify the downstream genes of LBD16/ASL18 using DNA microarray. Among 11 candidate genes, auxin-induced expression of two genes was repressed in arf7 arf19, slr-1 and lbd16-1 mutants. One of these genes was expressed specifically in LR primordia. In this poster, we will present the results of expression analysis and discuss the functions of several candidate genes.
