Short-term growth responses to ethylene in Arabidopsis seedlings are EIN3/EIL1 independent.
Kinetic studies indicate there are two phases to growth inhibition by ethylene for the hypocotyls of etiolated Arabidopsis seedlings. Phase I is transient, while phase II results in sustained growth inhibition. The EIN2 membrane protein is required for both the first and second phases of growth inhibition by ethylene, while the transcription factors EIN3 and EIL1 are required for the second phase but not the first phase. The first phase lasts no more than 2 h. It is less sensitive to the ethylene response inhibitor 1-methylcyclopropene and more sensitive to ethylene than the second phase. The first phase shows adaptation at low concentrations of ethylene (< or =0.01 microL L(-1)) with a relative refractory period of 5 h after ethylene is added. A modified signal transduction model is proposed that accounts for the two phases of growth inhibition.
Department of Botany, University of Wisconsin, Madison, Wisconsin 53706, USA.
Brad M
BM
Binder
Laura A
LA
Mortimore
Anna N
AN
Stepanova
Joseph R
JR
Ecker
Anthony B
AB
Bleecker
D000222:Adaptation, Physiological; D017360:Arabidopsis / Q000187:drug effects / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000502:physiology*; D003521:Cyclopropanes / Q000494:pharmacology; D004268:DNA-Binding Proteins; D004305:Dose-Response Relationship, Drug; D005030:Ethylenes / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant; D009687:Nuclear Proteins / Q000502:physiology; D010937:Plant Growth Regulators / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000502:physiology; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development; D013997:Time Factors; D014157:Transcription Factors / Q000502:physiology
D029681:Arabidopsis Proteins; D003521:Cyclopropanes; D004268:DNA-Binding Proteins; C494589:EIL1 protein, Arabidopsis; C119963:EIN2 protein, Arabidopsis; C106987:EIN3 protein, Arabidopsis; D005030:Ethylenes; D009687:Nuclear Proteins; D010937:Plant Growth Regulators; D011956:Receptors, Cell Surface; D014157:Transcription Factors; C036216:ethylene; C412563:1-methylcyclopropene