The Arabidopsis DELLA RGA-LIKE3 is a direct target of MYC2 and modulates jasmonate signaling responses.
Gibberellins (GAs) are plant hormones involved in the regulation of plant growth in response to endogenous and environmental signals. GA promotes growth by stimulating the degradation of nuclear growth-repressing DELLA proteins. In Arabidopsis thaliana, DELLAs consist of a small family of five proteins that display distinct but also overlapping functions in repressing GA responses. This study reveals that DELLA RGA-LIKE3 (RGL3) protein is essential to fully enhance the jasmonate (JA)-mediated responses. We show that JA rapidly induces RGL3 expression in a CORONATINE INSENSITIVE1 (COI1)- and JASMONATE INSENSITIVE1 (JIN1/MYC2)-dependent manner. In addition, we demonstrate that MYC2 binds directly to RGL3 promoter. Furthermore, we show that RGL3 (like the other DELLAs) interacts with JA ZIM-domain (JAZ) proteins, key repressors of JA signaling. These findings suggest that JA/MYC2-dependent accumulation of RGL3 represses JAZ activity, which in turn enhances the expression of JA-responsive genes. Accordingly, we show that induction of primary JA-responsive genes is reduced in the rgl3-5 mutant and enhanced in transgenic lines overexpressing RGL3. Hence, RGL3 positively regulates JA-mediated resistance to the necrotroph Botrytis cinerea and susceptibility to the hemibiotroph Pseudomonas syringae. We propose that JA-mediated induction of RGL3 expression is of adaptive significance and might represent a recent functional diversification of the DELLAs.
Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357, Conventioné avec l'Université de Strasbourg, 67084 Strasbourg, France.
Michael
M
Wild
Jean-Michel
JM
Davière
Soizic
S
Cheminant
Thomas
T
Regnault
Nicolas
N
Baumberger
Dimitri
D
Heintz
Rachel
R
Baltz
Pascal
P
Genschik
Patrick
P
Achard
D000220:Adaptation, Biological; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism*; D020171:Botrytis / Q000472:pathogenicity; D003517:Cyclopentanes / Q000378:metabolism / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005875:Gibberellins / Q000494:pharmacology; D047468:Immunoprecipitation; D054883:Oxylipins / Q000378:metabolism / Q000494:pharmacology*; D010935:Plant Diseases / Q000382:microbiology; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D025941:Protein Interaction Mapping; D044224:Pseudomonas syringae / Q000472:pathogenicity; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D020798:Two-Hybrid System Techniques
D029681:Arabidopsis Proteins; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; C112279:COI1 protein, Arabidopsis; D003517:Cyclopentanes; D005875:Gibberellins; C554741:JAZ1 protein, Arabidopsis; C473611:MYC2 protein, Arabidopsis; D054883:Oxylipins; C485889:RGL3 protein, Arabidopsis; D012097:Repressor Proteins; C011006:jasmonic acid; C007842:gibberellic acid