title: Sl-ERF2, a tomato ethylene response factor involved in ethylene response and seed germination.
abstract: Ethylene response factors (ERFs) are plant transcriptional regulators mediating ethylene-dependent gene expression via binding to the GCC motif found in the promoter region of ethylene-regulated genes. We report here on the structural and functional characterization of the tomato Sl-ERF2 gene that belongs to a distinct class of the large ERF gene family. Both spliced and unspliced versions of Sl-ERF2 transcripts were amplified from RNA samples and the search in the public tomato expressed sequence tag (EST) database confirmed the existence of the two transcript species in a number of cDNA libraries. The unspliced transcript contains two open reading frames yielding two hypothetical proteins, a small highly truncated version lacking the APETALA2 domain and a bigger protein lacking the N-terminal MCGGAAI(I)/(L) consensus peptide specific to ERF members from subfamily IV. Nevertheless, functional Sl-ERF2 protein may only derive from spliced transcripts since, depending on the tissue, the level of the spliced transcript is much higher than that of the unspliced transcript. Sl-ERF2 is expressed in all plant tissues tested, though its transcript accumulates preferentially in germinating seeds and ripening fruit. Overexpression of the Sl-ERF2 gene in transgenic tomato lines results in premature seed germination and enhanced hook formation of dark-grown seedlings, which is indicative of increased ethylene sensitivity. The expression of the mannanase2 gene is upregulated in Sl-ERF2-overexpressing seeds, suggesting that Sl-ERF2 stimulates seed germination through the induction of the mannanase2 gene. It is noteworthy that the exaggerated hook phenotype is abolished when ethylene perception is blocked, strongly suggesting that Sl-ERF2 requires other ethylene-dependent components to impact the hook formation process.
authors.affiliation: UMR990 INRA/INP-ENSA Toulouse Génomique et Biotechnologie des Fruits Avenue de l'Agrobiopole, BP 32607, 31326 Castanet-Tolosan cedex, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Pirrello
authors.forename: Fabiola
authors.initials: F
authors.lastname: Jaimes-Miranda
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Sanchez-Ballesta
authors.forename: Barthélémy
authors.initials: B
authors.lastname: Tournier
authors.forename: Qaiser
authors.initials: Q
authors.lastname: Khalil-Ahmad
authors.forename: Farid
authors.initials: F
authors.lastname: Regad
authors.forename: Alain
authors.initials: A
authors.lastname: Latché
authors.forename: Jean Claude
authors.initials: JC
authors.lastname: Pech
authors.forename: Mondher
authors.initials: M
authors.lastname: Bouzayen
mesh_terms: D017398:Alternative Splicing; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D005030:Ethylenes / Q000378:metabolism*; D005638:Fruit / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D018525:Germination; D018551:Solanum lycopersicum / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D008969:Molecular Sequence Data; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D012639:Seeds / Q000235:genetics / Q000254:growth & development*; D014170:Transformation, Genetic
chemical_list: D004268:DNA-Binding Proteins; D005030:Ethylenes; D010940:Plant Proteins; C036216:ethylene