title: ENTIRE and GOBLET promote leaflet development in tomato by modulating auxin response.
abstract: Compound leaves produce leaflets in a highly controlled yet flexible pattern. Here, we investigate the interaction between auxin, the putative auxin response inhibitor ENTIRE (E, SlIAA9) and the CUC transcription factor GOBLET (GOB) in compound-leaf development in tomato (Solanum lycopersicum). Auxin maxima, monitored by the auxin response sensor DR5, marked and preceded leaflet and lobe initiation. The DR5 signal increased, but maxima were partially retained in response to the external or internal elevation of auxin levels. E directly interacted with the auxin receptors SlTIR1 and SlAFB6. Furthermore, E was stabilized by a mutation in domain II of the protein and by the inhibition of auxin or proteasome activity, implying that E is subjected to auxin-mediated degradation. In e mutants the DR5 signal expanded to include the complete leaf margin, and leaf-specific overexpression of a stabilized form of E inhibited the DR5 signal and lamina expansion. Genetic manipulation of GOB activity altered the distribution of the DR5 signal, and the inhibition of auxin transport or activity suppressed the GOB overexpression phenotype, suggesting that auxin mediates GOB-regulated leaf patterning. Whereas leaves of single e or gob mutants developed only primary leaflets, the downregulation of both E and GOB resulted in the complete abolishment of leaflet initiation, and in a strong DR5 signal throughout the leaf margin. These results suggest that E and GOB modulate auxin response and leaflet morphogenesis via partly redundant pathways, and that proper leaflet initiation and separation requires distinct boundaries between regions of lamina growth and adjacent regions in which growth is inhibited.
authors.affiliation: The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture and The Otto Warburg Minerva Center for Agricultural Biotechnology, Hebrew University, P.O. Box 12, Rehovot 76100, Israel.
authors.forename: Hadas
authors.initials: H
authors.lastname: Ben-Gera
authors.forename: Ido
authors.initials: I
authors.lastname: Shwartz
authors.forename: Mon-Ray
authors.initials: MR
authors.lastname: Shao
authors.forename: Eilon
authors.initials: E
authors.lastname: Shani
authors.forename: Mark
authors.initials: M
authors.lastname: Estelle
authors.forename: Naomi
authors.initials: N
authors.lastname: Ori
mesh_terms: D003001:Cloning, Molecular; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism* / Q000494:pharmacology; D018551:Solanum lycopersicum / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D009154:Mutation; D018515:Plant Leaves / Q000254:growth & development*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D007210:Indoleacetic Acids; D010940:Plant Proteins; D014157:Transcription Factors