抄録
In higher plants, post-embryonic root growth depends on the activity of root apical meristem (RAM). The quiescent center (QC) in the RAM is essential to maintain the meristematic activity. To know the mechanism to maintain the QC activity, we are analyzing an Arabidopsis mutant, halted root (hlr). In hlr, the cellular organization of the RAM was disrupted, though its structure was normal in embryo. We showed that the normal QC identity was established during embryogenesis, but it was lost immediately after germination, whereas the specificity of differentiated tissues was maintained. These indicate that the HLR gene is required to maintain the normal QC identity. The HLR encodes a proteasome subunit, AtRPT2a. We showed that the HLR was expressed in the RAM including the QC, and that the proteasomal activity was reduced in hlr. We propose that proteasome-dependent programmed proteolysis is required to maintain the QC identity during post-embryonic root growth.
