Ectopic expression of the Arabidopsis ASYMMETRIC LEAVES2-LIKE5 (ASL5) gene in cockscomb (Celosia cristata) generates vascular-pattern modifications in lateral organs

Abstract

ASYMMETRIC LEAVES2-LIKE5/LATERAL ORGAN BOUNDARIES DOMAIN 12 (ASL5/LBD12), isolated from Arabidopsis, is a member of the LATERAL ORGAN BOUNDARIES (LOB) domain gene family. Previously, it has been reported that the dominant peacock1-D (pck1-D) mutant, wherein an ASL5 gene activated by a T-DNA lost apical dominance, had epinastic or abaxial leaves and was sterile; this suggested that ASL5 gene might be involved in ab-/adaxial determination of leaves or in the development of shoot apical meristems (SAMs), but no evidence for this has been provided hitherto. In this study, 35S:AtASL5-GFP transgenic cockscomb plants were obtained. In leaf epidermal cells, the AtASL5-GFP fusion protein displayed nuclear localization suggesting that AtASL5 might be a potential transcription factor. The 35S:AtASL5 transgenic cockscombs have dramatically altered phenotype. Histological analysis of petioles, leaf blades and lateral roots shows that these lateral organs have vascular-pattern modifications, suggesting the leaves might have ab-/adaxial defect, and the lateral roots have a central-peripheral defect. Moreover, ectopic protuberances were observed in transgenic plants, indicated that AtASL5 might have function in development of shoot apical meristem.