title: A cDNA microarray approach to decipher sunflower (Helianthus annuus) responses to the necrotrophic fungus Phoma macdonaldii.
abstract: To identify the genes involved in the partial resistance of sunflower (Helianthus annuus) to the necrotrophic fungus Phoma macdonaldii, we developed a 1000-element cDNA microarray containing carefully chosen genes putatively involved in primary metabolic pathways, signal transduction and biotic stress responses. A two-pass general linear model was used to normalize the data and then to detect differentially expressed genes. This method allowed us to identify 38 genes differentially expressed among genotypes, treatments and times, mainly belonging to plant defense, signaling pathways and amino acid metabolism. Based on a set of genes whose differential expression was highly significant, we propose a model in which negative regulation of a dual-specificity MAPK phosphatase could be implicated in sunflower defense mechanisms against the pathogen. The resulting activation of the MAP kinase cascade could subsequently trigger defense responses (e.g. thaumatin biosynthesis and phenylalanine ammonia lyase activation), under the control of transcription factors belonging to MYB and WRKY families. Concurrently, the activation of protein phosphatase 2A (PP2A), which is implicated in cell death inhibition, could limit pathogen development. The results reported here provide a valuable first step towards the understanding and analysis of the P. macdonaldii-sunflower interaction.
authors.affiliation: Laboratoire de Biotechnologies et Amélioration des Plantes (BAP), INP-ENSAT, Pôle de Biotechnologies Végétales, IFR 40, 18 Chemin de Borde Rouge, Auzeville, 31326 Castanet Tolosan, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Alignan
authors.forename: Tarek
authors.initials: T
authors.lastname: Hewezi
authors.forename: Michel
authors.initials: M
authors.lastname: Petitprez
authors.forename: Grégory
authors.initials: G
authors.lastname: Dechamp-Guillaume
authors.forename: Laurent
authors.initials: L
authors.lastname: Gentzbittel
mesh_terms: D001203:Ascomycota / Q000502:physiology*; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling / Q000379:methods*; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D006368:Helianthus / Q000033:anatomy & histology / Q000235:genetics* / Q000382:microbiology*; D007113:Immunity, Innate / Q000235:genetics; D020935:MAP Kinase Signaling System / Q000502:physiology; D008954:Models, Biological; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics; D015398:Signal Transduction; D013997:Time Factors
chemical_list: D010940:Plant Proteins