Abstract
In vascular plants, the maintenance of the activity in the root apical meristem is important for the development of the root architecture. To investigate the mechanisms of root meristem maintenance (RMM), we isolated the recessive mutant LR11-4 that showed the aberrant root growth from Arabidopsis. In the LR11-4 mutant, the length of the primary root is remarkably shorter than that of the wild type, and the frequency of lateral root (LR) formation is not affected but the LR growth is severely inhibited. Fine mapping and sequence analysis revealed that LR11-4 mutant genome has a non-sense mutation in the FBA1 gene, encoding a fructose-1,6-bisphosphate aldolase1 that functions in Calvin cycle. The complementation test showed that the LR11-4 phenotype is caused by the mutation in the FBA1. FBA1-GFP fusion protein expressed under the control of FBA1 genomic region was localized in the plastids of the root cap columella and leaves, strongly suggesting that the function of FBA1 in the plastids is necessary for RMM in Arabidopsis. We are now investigating which organs should express FBA1 for RMM.
