The ERECTA gene controls spatial and temporal patterns of epidermal cell number and size in successive developing leaves of Arabidopsis thaliana.

BACKGROUND AND AIMS ERECTA has been identified as a pleiotropic regulator of developmental and physiological processes in Arabidopsis thaliana. Previous work demonstrated a role for ERECTA in the control of compensation between epidermal cell expansion and division in leaves. METHODS In this work, spatial and temporal analyses of epidermal cell division and expansion were performed on successive developing vegetative leaves of Arabidopsis thaliana in both ERECTA and erecta lines, LER and Ler, respectively, to understand how the ERECTA gene regulates compensation between these two processes. KEY RESULTS The loss of ERECTA function leads to a low cell expansion rate in all zones of a leaf and in all successive leaves of a plant. This low cell expansion rate is counterbalanced by an increase in the duration of cell division. As a consequence, the ERECTA mutation eliminates the tip to base cellular gradient generally observed in the leaf epidermis and also flattens the heteroblastic changes in epidermal cell area and number within a rosette. Ablation of floral buds eliminates the heteroblastic changes in cellular patterns in an ERECTA-dependent manner. CONCLUSIONS The results provide a detailed description of changes in leaf growth dynamics and cellular variables in both LER and Ler. Altogether they suggest that ERECTA influences leaf cellular development in relation to whole plant ontogeny.