Tissue-Specific Regulation of Gibberellin Signaling Fine-Tunes Arabidopsis Iron-Deficiency Responses.
Iron is an essential element for most living organisms. Plants acquire iron from the rhizosphere and have evolved different biochemical and developmental responses to adapt to a low-iron environment. In Arabidopsis, FIT encodes a basic helix-loop-helix transcription factor that activates the expression of iron-uptake genes in root epidermis upon iron deficiency. Here, we report that the gibberellin (GA)-signaling DELLA repressors contribute substantially in the adaptive responses to iron-deficient conditions. When iron availability decreases, DELLAs accumulate in the root meristem, thereby restraining root growth, while being progressively excluded from epidermal cells in the root differentiation zone. Such DELLA exclusion from the site of iron acquisition relieves FIT from DELLA-dependent inhibition and therefore promotes iron uptake. Consistent with this mechanism, expression of a non-GA-degradable DELLA mutant protein in root epidermis interferes with iron acquisition. Hence, spatial distribution of DELLAs in roots is essential to fine-tune the adaptive responses to iron availability.
Institut de Biologie Moléculaire des Plantes, UPR2357, Associé avec l'Université de Strasbourg, 67084 Strasbourg, France.
Michael
M
Wild
Institut de Biologie Moléculaire des Plantes, UPR2357, Associé avec l'Université de Strasbourg, 67084 Strasbourg, France.
Jean-Michel
JM
Davière
Institut de Biologie Moléculaire des Plantes, UPR2357, Associé avec l'Université de Strasbourg, 67084 Strasbourg, France.
Thomas
T
Regnault
Institut de Biologie Moléculaire des Plantes, UPR2357, Associé avec l'Université de Strasbourg, 67084 Strasbourg, France.
Lali
L
Sakvarelidze-Achard
Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV, 46022 Valencia, Spain.
Esther
E
Carrera
Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV, 46022 Valencia, Spain.
Isabel
I
Lopez Diaz
Institut de Biologie Intégrative de la Cellule (I2BC), CNRS/CEA/University Paris-Sud, Université Paris-Saclay, Avenue de la Terrasse, 91190 Gif-sur-Yvette, France.
Anne
A
Cayrel
Institut de Biologie Intégrative de la Cellule (I2BC), CNRS/CEA/University Paris-Sud, Université Paris-Saclay, Avenue de la Terrasse, 91190 Gif-sur-Yvette, France.
Guillaume
G
Dubeaux
Institut de Biologie Intégrative de la Cellule (I2BC), CNRS/CEA/University Paris-Sud, Université Paris-Saclay, Avenue de la Terrasse, 91190 Gif-sur-Yvette, France.
Grégory
G
Vert
Institut de Biologie Moléculaire des Plantes, UPR2357, Associé avec l'Université de Strasbourg, 67084 Strasbourg, France. Electronic address: patrick.achard@ibmp-cnrs.unistra.fr.
Patrick
P
Achard
D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D005875:Gibberellins / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism
D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D005875:Gibberellins; D007501:Iron; D010937:Plant Growth Regulators; C501411:FIT1 protein, Arabidopsis; C109555:GAI protein, Arabidopsis
Arabidopsis thaliana; DELLA; FIT; iron deficiency; root epidermis