title: Development, characterization and experimental validation of a cultivated sunflower (Helianthus annuus L.) gene expression oligonucleotide microarray.
abstract: Oligonucleotide-based microarrays with accurate gene coverage represent a key strategy for transcriptional studies in orphan species such as sunflower, H. annuus L., which lacks full genome sequences. The goal of this study was the development and functional annotation of a comprehensive sunflower unigene collection and the design and validation of a custom sunflower oligonucleotide-based microarray. A large scale EST (>130,000 ESTs) curation, assembly and sequence annotation was performed using Blast2GO (www.blast2go.de). The EST assembly comprises 41,013 putative transcripts (12,924 contigs and 28,089 singletons). The resulting Sunflower Unigen Resource (SUR version 1.0) was used to design an oligonucleotide-based Agilent microarray for cultivated sunflower. This microarray includes a total of 42,326 features: 1,417 Agilent controls, 74 control probes for sunflower replicated 10 times (740 controls) and 40,169 different non-control probes. Microarray performance was validated using a model experiment examining the induction of senescence by water deficit. Pre-processing and differential expression analysis of Agilent microarrays was performed using the Bioconductor limma package. The analyses based on p-values calculated by eBayes (p<0.01) allowed the detection of 558 differentially expressed genes between water stress and control conditions; from these, ten genes were further validated by qPCR. Over-represented ontologies were identified using FatiScan in the Babelomics suite. This work generated a curated and trustable sunflower unigene collection, and a custom, validated sunflower oligonucleotide-based microarray using Agilent technology. Both the curated unigene collection and the validated oligonucleotide microarray provide key resources for sunflower genome analysis, transcriptional studies, and molecular breeding for crop improvement.
authors.affiliation: Instituto de Biotecnología, Centro de Investigaciones en Ciencias Agronómicas y Veterinarias, Instituto Nacional de Tecnología Agropecuaria, Hurlingham, Buenos Aires, Argentina.
authors.forename: Paula
authors.initials: P
authors.lastname: Fernandez
authors.forename: Marcelo
authors.initials: M
authors.lastname: Soria
authors.forename: David
authors.initials: D
authors.lastname: Blesa
authors.forename: Julio
authors.initials: J
authors.lastname: DiRienzo
authors.forename: Sebastian
authors.initials: S
authors.lastname: Moschen
authors.forename: Maximo
authors.initials: M
authors.lastname: Rivarola
authors.forename: Bernardo Jose
authors.initials: BJ
authors.lastname: Clavijo
authors.forename: Sergio
authors.initials: S
authors.lastname: Gonzalez
authors.forename: Lucila
authors.initials: L
authors.lastname: Peluffo
authors.forename: Dario
authors.initials: D
authors.lastname: Príncipi
authors.forename: Guillermo
authors.initials: G
authors.lastname: Dosio
authors.forename: Luis
authors.initials: L
authors.lastname: Aguirrezabal
authors.forename: Francisco
authors.initials: F
authors.lastname: García-García
authors.forename: Ana
authors.initials: A
authors.lastname: Conesa
authors.forename: Esteban
authors.initials: E
authors.lastname: Hopp
authors.forename: Joaquín
authors.initials: J
authors.lastname: Dopazo
authors.forename: Ruth Amelia
authors.initials: RA
authors.lastname: Heinz
authors.forename: Norma
authors.initials: N
authors.lastname: Paniego
mesh_terms: D020224:Expressed Sequence Tags; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D006368:Helianthus / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*