A Comparison of the Olfactory Gene Repertoires of Adults and Larvae in the Noctuid Moth Spodoptera littoralis

Abstract

To better understand the olfactory mechanisms in a lepidopteran pest model species, the cotton leafworm Spodoptera littoralis, we have recently established a partial transcriptome from adult antennae. Here, we completed this transcriptome using next generation sequencing technologies, namely 454 and Illumina, on both adult antennae and larval tissues, including caterpillar antennae and maxillary palps. All sequences were assembled in 77,643 contigs. Their analysis greatly enriched the repertoire of chemosensory genes in this species, with a total of 57 candidate odorant-binding and chemosensory proteins, 47 olfactory receptors, 6 gustatory receptors and 17 ionotropic receptors. Using RT-PCR, we conducted the first exhaustive comparison of olfactory gene expression between larvae and adults in a lepidopteran species. All the 127 candidate olfactory genes were profiled for expression in male and female adult antennae and in caterpillar antennae and maxillary palps. We found that caterpillars expressed a smaller set of olfactory genes than adults, with a large overlap between these two developmental stages. Two binding proteins appeared to be larvae-specific and two others were adult-specific. Interestingly, comparison between caterpillar antennae and maxillary palps revealed numerous organ-specific transcripts, suggesting the complementary involvement of these two organs in larval chemosensory detection. Adult males and females shared the same set of olfactory transcripts, except two male-specific candidate pheromone receptors, two male-specific and two female-specific odorant-binding proteins. This study identified transcripts that may be important for sex-specific or developmental stage-specific chemosensory behaviors.

Comparing the Expression of Olfaction-Related Genes in Gypsy Moth (Lymantria dispar) Adult Females and Larvae from One Flightless and Two Flight-Capable Populations

“…This number is similar to the one reported on a previous study comparing S. littoralis adult antennae and larval head capsules (127) (Poivet et al, 2013), and another study investigating the adult antennal transcriptome of H. armigera (131), and H. assulta (129) (the latter did not include GRs and we excluded sensory neuron membrane proteins from the total count) (Zhang et al, 2014). The conserved number of olfaction-related genes suggests a core group of genes control olfaction in moth species belonging to the superfamily Noctuoidea (Kristensen et al, 2007;Zahiri et al, 2011).…”

“…This report represents an expansive characterization of the chemosensory transcripts and their encoded proteins of L. dispar, and increases the number of available olfactory-related sequences for Lepidopteran species of agricultural relevance. Our results may also help unveil how the expression of chemosensory genes changes throughout insect development and as a result of speciation processes, together with similar reports for other species (Poivet et al, 2013;Zhang et al, 2014Zhang et al, , 2015Walker et al, 2016).…”

“…A study investigating expression patterns between adults and larvae of S. littoralis found that adults and larvae express similar numbers of OBPs and CSPs, while the caterpillar OR and IR repertoires were much smaller than the adult ones, and some GRs were found to be adult-specific (Poivet et al, 2013). We also encountered a similar number of CSPs being expressed in both stages and reduced IR, OR, and GR repertoires in the larval stages.…”

Análise do transcriptoma de <i>Podalia orsilochus</i> (Cramer, 1775).

“…Trabalhos esses que buscam elucidar e descobrir novas moléculas de interesse biotecnológico e farmacológico, visando à produção de biofármacos mais eficazes e de menores custos, e de potencial para a elaboração de novos métodos de controle de doenças (PAUCHET et al, 2010;POIVET et al, 2013;VOGEL et al, 2011).…”

“…Todos esses estudos visam descobrir moléculas de interesse biotecnológico ou simplesmente genes com histórias evolutivas que poderiam solucionar determinadas definições sistemáticas, 19 filogenéticas e taxômicas de um grupo específico (PAUCHET et al, 2010;POIVET et al, 2013;VOGEL et al, 2011).…”