Role of PIN-mediated auxin efflux in apical hook development ofArabidopsis thaliana

• DOI: 10.1242/dev.041277
• Publication Date: 2010-01-28T12:57:34Z
• Authors: Petra Žádníková; Jan Petrášek; Peter Marhavý; Vered Raz; Filip Vandenbussche; Zhaojun Ding; Kateřina Schwarze...; Miyo T. Morita; Masao Tasaka; Jan Hejátko; Dominique Van Der...; Jiří Friml; Eva Benková
• Keywords: 0301 basic medicine; PIN3 Apical hook Auxin Arabidopsis functional genomic analysis gene family-members box protein tir1 differential growth root gravitropism plant development cell elongation ethylene transport biosynthesis; Indoleacetic Acids; Arabidopsis Proteins; Recombinant Fusion Proteins; Meristem; Arabidopsis; Gene Expression Regulation, Developmental; Membrane Transport Proteins; Ethylenes; Genes, Plant; Plants, Genetically Modified; Models, Biological; 03 medical and health sciences; Gene Expression Regulation, Plant; Seedlings; Mutation

The apical hook of dark-grown Arabidopsis seedlings is a simple structure that develops soon after germination to protect the meristem tissues during emergence through the soil and that opens upon exposure to light. Differential growth at the apical hook proceeds in three sequential steps that are regulated by multiple hormones, principally auxin and ethylene. We show that the progress of the apical hook through these developmental phases depends on the dynamic, asymmetric distribution of auxin, which is regulated by auxin efflux carriers of the PIN family. Several PIN proteins exhibited specific, partially overlapping spatial and temporal expression patterns, and their subcellular localization suggested auxin fluxes during hook development. Genetic manipulation of individual PIN activities interfered with different stages of hook development, implying that specific combinations of PIN genes are required for progress of the apical hook through the developmental phases. Furthermore, ethylene might modulate apical hook development by prolonging the formation phase and strongly suppressing the maintenance phase. This ethylene effect is in part mediated by regulation of PIN-dependent auxin efflux and auxin signaling.