The cyclophilin A DIAGEOTROPICA gene affects auxin transport in both root and shoot to control lateral root formation
Por:
Ivanchenko, MG, Zhu, JS, Wang, BJ, Medvecka, E, Du, YL, Azzarello, E, Mancuso, S, Megraw, M, Filichkin, S, Dubrovsky, JG, Friml, J, Geisler, M
Publicada:
15 feb 2015
Resumen:
Cyclophilin A is a conserved peptidyl-prolyl cis-trans isomerase
(PPIase) best known as the cellular receptor of the immunosuppressant
cyclosporine A. Despite significant effort, evidence of developmental
functions of cyclophilin A in non-plant systems has remained obscure.
Mutations in a tomato (Solanum lycopersicum) cyclophilin A ortholog,
DIAGEOTROPICA (DGT), have been shown to abolish the organogenesis of
lateral roots; however, a mechanistic explanation of the phenotype is
lacking. Here, we show that the dgt mutant lacks auxin maxima relevant
to priming and specification of lateral root founder cells. DGT is
expressed in shoot and root, and localizes to both the nucleus and
cytoplasm during lateral root organogenesis. Mutation of ENTIRE/IAA9, a
member of the auxin-responsive Aux/IAA protein family of transcriptional
repressors, partially restores the inability of dgt to initiate lateral
root primordia but not the primordia outgrowth. By comparison, grafting
of a wild-type scion restores the process of lateral root formation,
consistent with participation of a mobile signal. Antibodies do not
detect movement of the DGT protein into the dgt rootstock; however,
experiments with radiolabeled auxin and an auxin-specific microelectrode
demonstrate abnormal auxin fluxes. Functional studies of DGT in
heterologous yeast and tobacco-leaf auxin-transport systems demonstrate
that DGT negatively regulates PIN-FORMED (PIN) auxin efflux transporters
by affecting their plasma membrane localization. Studies in tomato
support complex effects of the dgt mutation on PIN expression level,
expression domain and plasma membrane localization. Our data demonstrate
that DGT regulates auxin transport in lateral root formation.
Filiaciones:
Univ Nacl Autonoma Mexico, Inst Biotecnol, Dept Biol Mol Plantas, Cuernavaca 62210, Morelos, Mexico
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