Abstract
Background: Insects rely on olfaction to locate food, mates, and suitable oviposition sites for successful completion of their life cycle.
Agrilus planipennis Fairmaire (emerald ash borer) is a serious invasive insect pest that has killed tens of millions of North American ash (
Fraxinus spp) trees and threatens the very existence of the genus
Fraxinus. Adult
A. planipennis are attracted to host volatiles and conspecifics; however, to date no molecular knowledge exists on olfaction in
A. planipennis. Hence, we undertook an antennae-specific transcriptomic study to identify the repertoire of odor processing genes involved in
A. planipennis olfaction.
Methodology and Principal Findings: We acquired 139,085 Roche/454 GS FLX transcriptomic reads that were assembled into 30,615 high quality expressed sequence tags (ESTs), including 3,249 isotigs and 27,366 non-isotigs (contigs and singletons). Intriguingly, the majority of the
A. planipennis antennal transcripts (59.72%) did not show similarity with sequences deposited in the non-redundant database of GenBank, potentially representing novel genes. Functional annotation and KEGG analysis revealed pathways associated with signaling and detoxification. Several odor processing genes (9 odorant binding proteins, 2 odorant receptors, 1 sensory neuron membrane protein and 134 odorant/xenobiotic degradation enzymes, including cytochrome P450s, glutathione-S-transferases; esterases, etc.) putatively involved in olfaction processes were identified. Quantitative PCR of candidate genes in male and female
A. planipennis in different developmental stages revealed developmental- and sex-biased expression patterns.
Conclusions and Significance: The antennal ESTs derived from
A. planipennis constitute a rich molecular resource for the identification of genes potentially involved in the olfaction process of A. planipennis. These findings should help in understanding the processing of antennally-active compounds (e.g. 7-epi-sesquithujene) previously identified in this serious invasive pest.
Citation
Mamidala, Praveen; Wijeratne, Asela J.; Wijeratne, Saranga; Poland, Therese; Qazi, Sohail S.; Doucet, Daniel; Cusson, Michel; Beliveau, Catherine; Mittapalli, Omprakash; Marion-Poll, Frederic. 2013. Identification of odor-processing genes in the emerald ash borer,
Agrilus planipennis. PLoS ONE. 8(2): e56555. 15 p. https://doi.org/10.1371/journal.pone.0056555
