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An Expressed Sequence Tag collection from the male antennae of the Noctuid moth Spodoptera littoralis: a resource for olfactory and pheromone detection research.

Legeai F, Malpel S, Montagné N, Monsempes C, Cousserans F, Merlin C, François MC, Maïbèche-Coisné M, Gavory F, Poulain J, Jacquin-Joly E - BMC Genomics (2011)

Bottom Line: 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: 1IRISA, Equipe Symbiose, Campus Universitaire de Beaulieu, 35042 Rennes Cedex, France.

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.

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Number of proteins translated from S. littoralis antennal ORFs overlapping with the GenBank non-redundant protein database (NR). (7 686 184 entries, July 2009), the B. mori proteome (14 632 entries, SilkDB April 2008 release) and the D. melanogaster proteome (21 647 entries, FlyBase release v5.16) (e-value cut off: 1e-5).
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Figure 1: Number of proteins translated from S. littoralis antennal ORFs overlapping with the GenBank non-redundant protein database (NR). (7 686 184 entries, July 2009), the B. mori proteome (14 632 entries, SilkDB April 2008 release) and the D. melanogaster proteome (21 647 entries, FlyBase release v5.16) (e-value cut off: 1e-5).

Mentions: Among the 9033 unigenes, 6738 presented a coding region (74.6%, mean length: 215.14 aa, median length: 221 aa, max length: 922 aa, min length: 30 aa, table 1). Protein sequences translated from the predicted open reading frame (ORF) set were compared to the non-redundant protein database (NR) and to the D. melanogaster and B. mori complete proteomes (e-value cut off: 1e-5) (Figure 1). Most of the sequences (90%) translated from predicted ORFs, showed similarity to known proteins. 678 ORFs presented no similarity at all. The 972 protein sequences having no similarity with the B. mori proteome were further compared to the B. mori genome using TBLASTX (e-value cut off: 1e-20), since the B. mori protein prediction available in SilkDB may have missed some genes. 713 remaining S. littoralis protein sequences had no similarity with any B. mori gene. 50 were classified in a gene ontology term and were analyzed using BLAST2GO (Additional file 3). Interestingly, we found enrichment in putative proteins involved in defense response to bacteria (FDR: 7,21E-004), antifungal humoral response (2,04E-006), xenobiotic metabolism processes (8,08E-006) and interaction between organisms (1,56E-007). An enrichment in defense-related objects was recently observed by Vogel et al [36] in the transcriptome of the noctuid Heliothis virescens pheromone glands, when compared to that of B. mori.


An Expressed Sequence Tag collection from the male antennae of the Noctuid moth Spodoptera littoralis: a resource for olfactory and pheromone detection research.

Legeai F, Malpel S, Montagné N, Monsempes C, Cousserans F, Merlin C, François MC, Maïbèche-Coisné M, Gavory F, Poulain J, Jacquin-Joly E - BMC Genomics (2011)

Number of proteins translated from S. littoralis antennal ORFs overlapping with the GenBank non-redundant protein database (NR). (7 686 184 entries, July 2009), the B. mori proteome (14 632 entries, SilkDB April 2008 release) and the D. melanogaster proteome (21 647 entries, FlyBase release v5.16) (e-value cut off: 1e-5).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3045336&req=5

Figure 1: Number of proteins translated from S. littoralis antennal ORFs overlapping with the GenBank non-redundant protein database (NR). (7 686 184 entries, July 2009), the B. mori proteome (14 632 entries, SilkDB April 2008 release) and the D. melanogaster proteome (21 647 entries, FlyBase release v5.16) (e-value cut off: 1e-5).
Mentions: Among the 9033 unigenes, 6738 presented a coding region (74.6%, mean length: 215.14 aa, median length: 221 aa, max length: 922 aa, min length: 30 aa, table 1). Protein sequences translated from the predicted open reading frame (ORF) set were compared to the non-redundant protein database (NR) and to the D. melanogaster and B. mori complete proteomes (e-value cut off: 1e-5) (Figure 1). Most of the sequences (90%) translated from predicted ORFs, showed similarity to known proteins. 678 ORFs presented no similarity at all. The 972 protein sequences having no similarity with the B. mori proteome were further compared to the B. mori genome using TBLASTX (e-value cut off: 1e-20), since the B. mori protein prediction available in SilkDB may have missed some genes. 713 remaining S. littoralis protein sequences had no similarity with any B. mori gene. 50 were classified in a gene ontology term and were analyzed using BLAST2GO (Additional file 3). Interestingly, we found enrichment in putative proteins involved in defense response to bacteria (FDR: 7,21E-004), antifungal humoral response (2,04E-006), xenobiotic metabolism processes (8,08E-006) and interaction between organisms (1,56E-007). An enrichment in defense-related objects was recently observed by Vogel et al [36] in the transcriptome of the noctuid Heliothis virescens pheromone glands, when compared to that of B. mori.

Bottom Line: 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: 1IRISA, Equipe Symbiose, Campus Universitaire de Beaulieu, 35042 Rennes Cedex, France.

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.

Show MeSH
Related in: MedlinePlus