title: An Expressed Sequence Tag collection from the male antennae of the Noctuid moth Spodoptera littoralis: a resource for olfactory and pheromone detection research.
abstract: BACKGROUND
  Nocturnal insects such as moths are ideal models to study the molecular bases of olfaction that they use, among examples, for the detection of mating partners and host plants. Knowing how an odour generates a neuronal signal in insect antennae is crucial for understanding the physiological bases of olfaction, and also could lead to the identification of original targets for the development of olfactory-based control strategies against herbivorous moth pests. Here, we describe an Expressed Sequence Tag (EST) project to characterize the antennal transcriptome of the noctuid pest model, Spodoptera littoralis, and to identify candidate genes involved in odour/pheromone detection.
  
  
  RESULTS
  By targeting cDNAs from male antennae, we biased gene discovery towards genes potentially involved in male olfaction, including pheromone reception. A total of 20760 ESTs were obtained from a normalized library and were assembled in 9033 unigenes. 6530 were annotated based on BLAST analyses and gene prediction software identified 6738 ORFs. The unigenes were compared to the Bombyx mori proteome and to ESTs derived from Lepidoptera transcriptome projects. We identified a large number of candidate genes involved in odour and pheromone detection and turnover, including 31 candidate chemosensory receptor genes, but also genes potentially involved in olfactory modulation.
  
  
  CONCLUSIONS
  Our project has generated a large collection of antennal transcripts from a Lepidoptera. The normalization process, allowing enrichment in low abundant genes, proved to be particularly relevant to identify chemosensory receptors in a species for which no genomic data are available. Our results also suggest that olfactory modulation can take place at the level of the antennae itself. These EST resources will be invaluable for exploring the mechanisms of olfaction and pheromone detection in S. littoralis, and for ultimately identifying original targets to fight against moth herbivorous pests.
authors.affiliation: 1IRISA, Equipe Symbiose, Campus Universitaire de Beaulieu, 35042 Rennes Cedex, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Legeai
authors.forename: Sébastien
authors.initials: S
authors.lastname: Malpel
authors.forename: Nicolas
authors.initials: N
authors.lastname: Montagné
authors.forename: Christelle
authors.initials: C
authors.lastname: Monsempes
authors.forename: François
authors.initials: F
authors.lastname: Cousserans
authors.forename: Christine
authors.initials: C
authors.lastname: Merlin
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: François
authors.forename: Martine
authors.initials: M
authors.lastname: Maïbèche-Coisné
authors.forename: Frédérick
authors.initials: F
authors.lastname: Gavory
authors.forename: Julie
authors.initials: J
authors.lastname: Poulain
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Jacquin-Joly
mesh_terms: D000818:Animals; D057506:Arthropod Antennae / Q000378:metabolism*; D030541:Databases, Genetic; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D015723:Gene Library; D017344:Genes, Insect; D008297:Male; D058977:Molecular Sequence Annotation; D010675:Pheromones / Q000378:metabolism; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012903:Smell / Q000235:genetics*; D018411:Spodoptera / Q000235:genetics*
chemical_list: D010675:Pheromones