Abstract
Lateral root (LR) formation in Arabidopsis is regulated by auxin-responsive transcription through ARF7, ARF19 and Aux/IAAs. ARF7/19 directly activate the transcription of Lateral Organ Boundaries domain 16/Asymmetric Leaves2-like 18 (LBD16/ASL18) gene, and overexpression of LBD16/ASL18 induces LR formation in arf7 arf19 mutant, strongly suggesting that LBD16/ASL18 positively regulates LR formation downstream of ARF7/19 (Okushima et al., 2007, Plant Cell). As LBD16 was thought to be a transcriptional activator, we identified the downstream genes of LBD16 using DNA microarray. One of these downstream genes, LLPL2, was specifically expressed in LR primordia. LLPL2 encodes an unknown protein with a conserved amino acid sequence motif (LLPL). LLPL2-GFP fusion protein expressed under the control of the native promoter was also specifically observed in the dividing protoxylem pericycle cells during LR initiation. In this poster, we will discuss a possible role of LLPL2 in LR formation.
