Project description:Arabidopsis thaliana AF7/ARF19 double knockout with ARF7 reintroduced under its own promotor with a glucocorticoid receptor added were treated with Auxin, Dexamethazone and cycloheximide to determine primary and secondary ARF7 auxin sensitive downstream targets
Project description:The phytohormone auxin plays crucial roles in nearly every aspect of plant growth and development. The AUXIN RESPONSE FACTOR (ARF) family of transcription factors regulates auxin-responsive gene expression and exhibit nuclear localization in regions of high auxin responsiveness. Here we show that activating ARF7 and ARF19 proteins accumulate in micron-sized assemblies within the cytoplasm of tissues with attenuated auxin responsiveness. The intrinsically disordered middle region and the folded PB1 interaction domain of ARFs drive protein assembly formation. Mutation of a single lysine within the PB1 domain abrogates cytoplasmic assemblies, promotes ARF nuclear localization, and results in an altered transcriptome and morphological defects. Our data suggest a model in which ARF nucleo-cytoplasmic partitioning regulates auxin responsiveness, thus providing a mechanism for cellular competence for auxin signaling.
Project description:Lateral roots (LRs) are formed post-embryonically and contribute to root architecture formation in vascular plants. LATERAL ORGAN BOUNDARIES-DOMAIN 16 (LBD16) is a key transcription factor to initiate LR formation. LBD16 functions downstream of AUXIN RESPONSE FACTOR 7 (ARF7) and ARF19, and overexpression of LBD16 partially restores LR formation in the absence of ARF7 and ARF19. To identify downstream targets of LBD16, we engineered a transgenic line with inducible LBD16 activity by overexpressing a fusion protein of LBD16 and rat glucocorticoid receptor (GR) in arf7 arf19 mutant. Here we identified primary response genes of LBD16 from transcriptome analysis of 35Spro:LBD16:GR arf7 arf19 line.