title: The Arabidopsis mutant eer2 has enhanced ethylene responses in the light.
abstract: By screening for ethylene response mutants in Arabidopsis, a novel mutant, eer2, was isolated which displays enhanced ethylene responses. On a low nutrient medium (LNM) light-grown eer2 seedlings showed a significant hypocotyl elongation in response to low levels of 1-amino-cyclopropane-1-carboxylate (ACC), the precursor of ethylene, compared with the wild type, indicating that eer2 is hypersensitive to ethylene. Treatment with 1-MCP (1-methylcyclopropene), a competitive inhibitor of ethylene signalling, suppressed this hypersensitive response, demonstrating that it is a bona fide ethylene effect. By contrast, roots of eer2 were less sensitive than the wild type to low concentrations of ACC. The ethylene levels in eer2 did not differ from the wild type, indicating that ethylene overproduction is not the primary cause of the eer2 phenotype. In addition to its enhanced ethylene response of hypocotyls, eer2 is also affected in the pattern of senescence and its phenotype depends on the nutritional status of the growth medium. Furthermore, linkage analysis of eer2 suggests that this mutant defines a new locus in ethylene signalling.
authors.affiliation: Unit Plant Hormone Signaling and Bio-imaging, Department of Molecular Genetics, Ghent University, KL Ledeganckstraat 35, B-9000 Gent, Belgium.
authors.forename: Annelies
authors.initials: A
authors.lastname: De Paepe
authors.forename: Liesbeth
authors.initials: L
authors.lastname: De Grauwe
authors.forename: Sophie
authors.initials: S
authors.lastname: Bertrand
authors.forename: Jan
authors.initials: J
authors.lastname: Smalle
authors.forename: Dominique
authors.initials: D
authors.lastname: Van der Straeten
mesh_terms: D000598:Amino Acids, Cyclic / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D001483:Base Sequence; D002734:Chlorophyll / Q000378:metabolism; D002874:Chromosome Mapping; D003521:Cyclopropanes / Q000494:pharmacology; D017931:DNA Primers; D005030:Ethylenes / Q000494:pharmacology*; D008027:Light; D009154:Mutation; D018749:RNA, Plant / Q000235:genetics / Q000302:isolation & purification; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects
chemical_list: D000598:Amino Acids, Cyclic; D003521:Cyclopropanes; D017931:DNA Primers; D005030:Ethylenes; D018749:RNA, Plant; D002734:Chlorophyll; C023863:1-aminocyclopropane-1-carboxylic acid; C105498:1-methylcyclopropane; C036216:ethylene