title: Changes in transcriptional profiles are associated with early fruit tissue specialization in tomato.
abstract: The cell expansion phase contributes in determining the major characteristics of a fleshy fruit and represents two-thirds of the total fruit development in tomato (Solanum lycopersicum). So far, it has received very little attention. To evaluate the interest of a genomic scale approach, we performed an initial sequencing of approximately 1,200 cell expansion stage-related sequence tags from tomato fruit at 8, 12, and 15 d post anthesis. Interestingly, up to approximately 35% of the expressed sequence tags showed no homology with available tomato expressed sequence tags and up to approximately 21% with any known gene. Microarrays spotted with expansion phase-related cDNAs and other fruit cDNAs involved in various developmental processes were used (1) to profile gene expression in developing fruit and other plant organs and (2) to compare two growing fruit tissues engaged mostly in cell division (exocarp) or in cell expansion (locular tissue surrounding the seeds). Reverse transcription-polymerase chain reaction analysis was further used to confirm microarray results and to specify expression profiles of selected genes (24) in various tissues from expanding fruit. The wide range of genes expressed in the exocarp is consistent with a protective function and with a high metabolic activity of this tissue. In addition, our data show that the expansion of locular cells is concomitant with the expression of genes controlling water flow, organic acid synthesis, sugar storage, and photosynthesis and suggest that hormones (auxin and gibberellin) regulate this process. The data presented provide a basis for tissue-specific analyses of gene function in growing tomato fruit.
authors.affiliation: Unité Mixte de Recherche 619, Physiologie et Biotechnologie Végétales, Institut de Biologie Végétale Intégrative, Institut National de la Recherche Agronomique, Universités Bordeaux 1 et Victor Segalen Bordeaux 2, Villenave d'Ornon, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Lemaire-Chamley
authors.forename: Johann
authors.initials: J
authors.lastname: Petit
authors.forename: Virginie
authors.initials: V
authors.lastname: Garcia
authors.forename: Daniel
authors.initials: D
authors.lastname: Just
authors.forename: Pierre
authors.initials: P
authors.lastname: Baldet
authors.forename: Véronique
authors.initials: V
authors.lastname: Germain
authors.forename: Mathilde
authors.initials: M
authors.lastname: Fagard
authors.forename: Mariam
authors.initials: M
authors.lastname: Mouassite
authors.forename: Catherine
authors.initials: C
authors.lastname: Cheniclet
authors.forename: Christophe
authors.initials: C
authors.lastname: Rothan
mesh_terms: D048429:Cell Size; D018076:DNA, Complementary / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D020224:Expressed Sequence Tags; D005638:Fruit / Q000166:cytology / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005875:Gibberellins / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D018551:Solanum lycopersicum / Q000166:cytology / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D010788:Photosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
chemical_list: D018076:DNA, Complementary; D018744:DNA, Plant; D005875:Gibberellins; D007210:Indoleacetic Acids