title: Primary metabolic pathways and signal transduction in sunflower (Helianthus annuus L.): comparison of transcriptional profiling in leaves and immature embryos using cDNA microarrays.
abstract: The early stage of embryo development is a critical step in plant production. To identify genes with potential roles in the early sunflower seed development, a cDNA microarray approach was employed. We developed a thematic cDNA microarray containing clones representing high sequence similarities with known or predicted Arabidopsis genes implicated in different metabolic and signal transduction pathways. This 800-element cDNA array was used to compare the expression patterns in leaves and immature embryos (2 mm and 6 mm). Statistical analysis, using two-step ANOVA, revealed that 143 cDNA clones can be considered as differentially expressed. Of these, 62 clones were found to be up-regulated in leaves, 81 in embryos whereas only seven clones displayed increased level of mRNA in the 6 mm embryos when compared with 2 mm embryos. The differentially expressed clones are distributed among many metabolic and signal transduction pathways. For example, genes related to fatty acid metabolism and amino acid biosynthesis exhibited preferential expression patterns in immature embryos. Also, clones potentially encoding enzymes involved in the metabolism of ascorbate and aldarate, pyruvate, propanoate and inositol, and citrate cycle were found to be up-regulated in embryos. In contrast, cDNA clones putatively involved in energy metabolism were more abundant in leaves than embryos. Clones encoding potential signal transduction components including receptors, protein kinases, protein phosphatases, and transcription factors were also identified, with preferential expression profiles in immature embryos. The expression patterns derived from this study provide initial characterization of metabolic pathways and signalling transduction networks occurring in the early stage of sunflower seed development.
authors.affiliation: Laboratoire de Biotechnologies et Amèlioration des Plantes, Ecole Nationale Supérieure Agronomique de Toulouse, Avenue de l'Agrobiopôle, BP 107, Auzeville Tolosane, Castanet Tolosan, 31326 France.
authors.forename: Tarek
authors.initials: T
authors.lastname: Hewezi
authors.forename: Michel
authors.initials: M
authors.lastname: Petitprez
authors.forename: Laurent
authors.initials: L
authors.lastname: Gentzbittel
mesh_terms: D000704:Analysis of Variance; D020869:Gene Expression Profiling; D006368:Helianthus / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D008957:Models, Genetic; D020411:Oligonucleotide Array Sequence Analysis; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D020033:Protein Isoforms; D014157:Transcription Factors; D010749:Phosphoprotein Phosphatases