Plant responses to ethylene gas are mediated by SCF(EBF1/EBF2)-dependent proteolysis of EIN3 transcription factor.
Plants use ethylene gas as a signal to regulate myriad developmental processes and stress responses. The Arabidopsis EIN3 protein is a key transcription factor mediating ethylene-regulated gene expression and morphological responses. Here, we report that EIN3 protein levels rapidly increase in response to ethylene and this response requires several ethylene-signaling pathway components including the ethylene receptors (ETR1 and EIN4), CTR1, EIN2, EIN5, and EIN6. In the absence of ethylene, EIN3 is quickly degraded through a ubiquitin/proteasome pathway mediated by two F box proteins, EBF1 and EBF2. Plants containing mutations in either gene show enhanced ethylene response by stabilizing EIN3, whereas efb1 efb2 double mutants show constitutive ethylene phenotypes. Plants overexpressing either F box gene display ethylene insensitivity and destabilization of EIN3 protein. These results reveal that a ubiquitin/proteasome pathway negatively regulates ethylene responses by targeting EIN3 for degradation, and pinpoint EIN3 regulation as the key step in the response to ethylene.
Guo
Hongwei
H
Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
Ecker
Joseph R
JR
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000302:isolation & purification*; D003546:Cysteine Endopeptidases / Q000187:drug effects / Q000378:metabolism; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D004268:DNA-Binding Proteins; D005030:Ethylenes / Q000378:metabolism* / Q000494:pharmacology; D044782:F-Box Motifs / Q000187:drug effects / Q000235:genetics; D044783:F-Box Proteins / Q000235:genetics / Q000302:isolation & purification*; D025461:Feedback, Physiological / Q000187:drug effects / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000187:drug effects / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D046988:Proteasome Endopeptidase Complex; D011499:Protein Processing, Post-Translational / Q000187:drug effects / Q000235:genetics; D044843:SKP Cullin F-Box Protein Ligases / Q000235:genetics / Q000302:isolation & purification*; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D014157:Transcription Factors
D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; C481044:EBF1 protein, Arabidopsis; C481045:EBF2 protein, Arabidopsis; C106987:EIN3 protein, Arabidopsis; D005030:Ethylenes; D044783:F-Box Proteins; D009097:Multienzyme Complexes; D009687:Nuclear Proteins; D014157:Transcription Factors; C036216:ethylene; D044843:SKP Cullin F-Box Protein Ligases; D010447:Peptide Hydrolases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex