Loss-of-function mutations in the ethylene receptor ETR1 cause enhanced sensitivity and exaggerated response to ethylene in Arabidopsis.
Ethylene signaling in Arabidopsis begins at a family of five ethylene receptors that regulate activity of a downstream mitogen-activated protein kinase kinase kinase, CTR1. Triple and quadruple loss-of-function ethylene receptor mutants display a constitutive ethylene response phenotype, indicating they function as negative regulators in this pathway. No ethylene-related phenotype has been described for single loss-of-function receptor mutants, although it was reported that etr1 loss-of-function mutants display a growth defect limiting plant size. In actuality, this apparent growth defect results from enhanced responsiveness to ethylene; a phenotype manifested in all tissues tested. The phenotype displayed by etr1 loss-of-function mutants was rescued by treatment with an inhibitor of ethylene perception, indicating that it is ethylene dependent. Identification of an ethylene-dependent phenotype for a loss-of-function receptor mutant gave a unique opportunity for genetic and biochemical analysis of upstream events in ethylene signaling, including demonstration that the dominant ethylene-insensitive phenotype of etr2-1 is partially dependent on ETR1. This work demonstrates that mutational loss of the ethylene receptor ETR1 alters responsiveness to ethylene in Arabidopsis and that enhanced ethylene response in Arabidopsis not only results in increased sensitivity but exaggeration of response.
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Jesse D
JD
Department of Biochemistry, University of California, Riverside, California 92521, USA.
Larsen
Paul B
PB
D000475:Alkenes / Q000494:pharmacology; D000598:Amino Acids, Cyclic / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics*; D027682:Cation Transport Proteins; D000079923:Copper Transporter 1; D005030:Ethylenes / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018546:Hypocotyl / Q000187:drug effects; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D018515:Plant Leaves / Q000187:drug effects; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects; D011485:Protein Binding; D011494:Protein Kinases; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D012834:Silver / Q000494:pharmacology; D020798:Two-Hybrid System Techniques
D000475:Alkenes; D000598:Amino Acids, Cyclic; C490078:CTR1 protein, S cerevisiae; D027682:Cation Transport Proteins; D000079923:Copper Transporter 1; D005030:Ethylenes; D008565:Membrane Proteins; D010940:Plant Proteins; D011956:Receptors, Cell Surface; D029701:Saccharomyces cerevisiae Proteins; C083750:ethylene receptors, plant; C023863:1-aminocyclopropane-1-carboxylic acid; D012834:Silver; C036216:ethylene; C013658:propylene; D011494:Protein Kinases; C477753:CTR1 protein, Arabidopsis