title: Ethylene negatively regulates EXPA5 expression in Arabidopsis thaliana.
abstract: We examined the effects of ethylene on the expression of Arabidopsis expansins (AtEXPs). Among the AtEXPs tested, transcription of the AtEXPA5 gene was reduced most by exogenous ethylene. 2-Aminoethoxyvinylglycine, an ethylene biosynthesis inhibitor, increased AtEXPA5 transcription. Ethylene insensitive (ein7) and constitutive (ctr1) mutants resulted in increased and decreased transcription, respectively, thereby suggesting that ethylene endogenously downregulates AtEXPA5 expression. Hypocotyl elongation followed the same trend as AtEXPA5 expression, implying that changes in hypocotyl elongation reflect changes in AtEXPA5 expression. A transgenic plant line that overexpresses AtEXPA5, 35S-EXPA5, showed a reduced response to exogenous ethylene in terms of hypocotyl lengths when compared to wild-type and expA5-1, a knockout mutant. These results and the dose-dependent effect of aminocyclopropane-1-carboxyl acid on hypocotyl elongation implicate AtEXPA5 overexpression in making tissues more sensitive to high doses of ethylene. In summary, AtEXPA5 appears to respond to ethylene and play a role in ethylene regulating hypocotyl elongation in Arabidopsis thaliana.
authors.affiliation: Department of Life Science, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Son
authors.forename: Soo Chul
authors.initials: SC
authors.lastname: Chang
authors.forename: Chan Ho
authors.initials: CH
authors.lastname: Park
authors.forename: Seong-Ki
authors.initials: SK
authors.lastname: Kim
mesh_terms: D000598:Amino Acids, Cyclic / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D060406:Brassinosteroids / Q000494:pharmacology; D003470:Culture Media; D005030:Ethylenes / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D018546:Hypocotyl / Q000187:drug effects / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics* / Q000378:metabolism; D013260:Steroids, Heterocyclic / Q000494:pharmacology; D014158:Transcription, Genetic
chemical_list: D000598:Amino Acids, Cyclic; D060406:Brassinosteroids; D003470:Culture Media; D005030:Ethylenes; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D013260:Steroids, Heterocyclic; C095825:expansin protein, plant; C023863:1-aminocyclopropane-1-carboxylic acid; C036216:ethylene; C088137:aminoethoxyvinylglycine; D005998:Glycine; C023623:brassinolide