Differential regulation of EIN3 stability by glucose and ethylene signalling in plants.
Glucose is a global regulator of growth and metabolism that is evolutionarily conserved from unicellular microorganisms to multicellular animals and plants. In photosynthetic plants, glucose shows hormone-like activities and modulates many essential processes, including embryogenesis, germination, seedling development, vegetative growth, reproduction and senescence. Genetic and phenotypic analyses of Arabidopsis mutants with glucose-insensitive (gin) and glucose-oversensitive (glo) phenotypes have identified an unexpected antagonistic interaction between glucose and the plant stress hormone ethylene. The ethylene-insensitive etr1 and ein2 mutants have glo phenotypes, whereas the constitutive ethylene signalling mutant ctr1 is allelic to gin4 (refs 4, 5). The precise molecular mechanisms underlying the complex signalling network that governs plant growth and development in response to nutrients and plant hormones are mostly unknown. Here we show that glucose enhances the degradation of ETHYLENE-INSENSITIVE3 (EIN3), a key transcriptional regulator in ethylene signalling, through the plant glucose sensor hexokinase. Ethylene, by contrast, enhances the stability of EIN3. The ein3 mutant has a glo phenotype, and overexpression of EIN3 in transgenic Arabidopsis decreases glucose sensitivity.
Yanagisawa
Shuichi
S
Research Institute for Bioresources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan. yanagi-s@rib.okayama-u.ac.jp
Yoo
Sang-Dong
SD
Sheen
Jen
J
D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D005030:Ethylenes / Q000378:metabolism / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D030821:Plants, Genetically Modified; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D011523:Protoplasts / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D014157:Transcription Factors; D003313:Zea mays / Q000166:cytology / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C106987:EIN3 protein, Arabidopsis; D005030:Ethylenes; D009687:Nuclear Proteins; D014157:Transcription Factors; C036216:ethylene; D005947:Glucose