Abstract
The members of CLE gene family encode 12 amino acid peptides homologous to CLAVATA3 on their C-terminus regions. The CLE peptides are thought to regulate the size of the apical meristem and their differentiation. In this study, we focused on root-expressed NH4+-regulated form, CLE3, of Arabidopsis to elucidate its roles in root development.
Expression of CLE3 was induced by low NO3- but was repressed by high NO3-. When NH4+ was the sole nitrogen source, CLE3 was repressed by 300 μM NH4+, though increased either by increasing or decreasing the amount of NH4+ in the medium. The CLE3 expression level was negatively correlated with the root fresh weight. CLE3 promoter-GFP plants indicated that CLE3 is expressed in the central cylinder roots. The lengths of the lateral roots were shorter in CLE3 overexpressors than in the wild-type plants, suggesting that CLE3 may act as a repressor of lateral root elongation.
