Abstract
In vascular plants, the maintenance of activity in the root apical meristem is essential for the development of root architecture. To get insight into the mechanisms of root meristem maintenance, we isolated the recessive mutant LR11-4 that showed aberrant root growth and development in Arabidopsis. The length of the primary root in this mutant was about 50% of that in the wild type, whereas the frequency of lateral root formation remains unaffected. The lateral root growth was strongly inhibited in LR11-4. Fine mapping and sequence analysis revealed LR11-4 mutant genome to have a non-sense mutation in the FBA1 gene, encoding a fructose-1,6-bisphosphate aldolase1 that functions in Calvin cycle. This was confirmed by the complementation test of LR1-4 mutant with the transgene expressing FBA1 under the native FBA1 promoter. We also observed that FBA1-GFP fusion protein expressed under the control of FBA1 genomic region was localized in the plastids of the root cap columella and leaves. These results strongly suggest the involvement of FBA1 in root meristem maintenance in Arabidopsis.
