title: Functional characterization of a tomato COBRA-like gene functioning in fruit development and ripening.
abstract: BACKGROUND
  Extensive studies have demonstrated that the COBRA gene is critical for biosynthesis of cell wall constituents comprising structural tissues of roots, stalks, leaves and other vegetative organs, however, its role in fruit development and ripening remains largely unknown.
  
  
  RESULTS
  We identified a tomato gene (SlCOBRA-like) homologous to Arabidopsis COBRA, and determined its role in fleshy fruit biology. The SlCOBRA-like gene is highly expressed in vegetative organs and in early fruit development, but its expression in fruit declines dramatically during ripening stages, implying a primary role in early fruit development. Fruit-specific suppression of SlCOBRA-like resulted in impaired cell wall integrity and up-regulation of genes encoding proteins involved in cell wall degradation during early fruit development. In contrast, fruit-specific overexpression of SlCOBRA-like resulted in increased wall thickness of fruit epidermal cells, more collenchymatous cells beneath the epidermis, elevated levels of cellulose and reduced pectin solubilization in the pericarp cells of red ripe fruits. Moreover, transgenic tomato fruits overexpressing SlCOBRA-like exhibited desirable early development phenotypes including enhanced firmness and a prolonged shelf life.
  
  
  CONCLUSIONS
  Our results suggest that SlCOBRA-like plays an important role in fruit cell wall architecture and provides a potential genetic tool for extending the shelf life of tomato and potentially additional fruits.
authors.affiliation: Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Cao
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Tang
authors.forename: Jim
authors.initials: J
authors.lastname: Giovannoni
authors.forename: Fangming
authors.initials: F
authors.lastname: Xiao
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Liu
mesh_terms: D002473:Cell Wall / Q000235:genetics / Q000378:metabolism; D005638:Fruit / Q000033:anatomy & histology / Q000166:cytology / Q000235:genetics* / Q000254:growth & development*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D018551:Solanum lycopersicum / Q000033:anatomy & histology / Q000166:cytology / Q000235:genetics* / Q000254:growth & development*; D046911:Macromolecular Substances / Q000378:metabolism; D005810:Multigene Family; D010641:Phenotype; D010802:Phylogeny; D019441:Plant Epidermis / Q000166:cytology / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D015398:Signal Transduction / Q000235:genetics; D017550:Spectroscopy, Fourier Transform Infrared; D015854:Up-Regulation / Q000235:genetics
chemical_list: D046911:Macromolecular Substances; D010940:Plant Proteins