Antennal and Abdominal Transcriptomes Reveal Chemosensory Genes in the Asian Citrus Psyllid, Diaphorina citri

PLoS One. 2016 Jul 21;11(7):e0159372. doi: 10.1371/journal.pone.0159372. eCollection 2016.

Abstract

The Asian citrus psyllid, Diaphorina citri is the principal vector of the highly destructive citrus disease called Huanglongbing (HLB) or citrus greening, which is a major threat to citrus cultivation worldwide. More effective pest control strategies against this pest entail the identification of potential chemosensory proteins that could be used in the development of attractants or repellents. However, the molecular basis of olfaction in the Asian citrus psyllid is not completely understood. Therefore, we performed this study to analyze the antennal and abdominal transcriptome of the Asian citrus psyllid. We identified a large number of transcripts belonging to nine chemoreception-related gene families and compared their expression in male and female adult antennae and terminal abdomen. In total, 9 odorant binding proteins (OBPs), 12 chemosensory proteins (CSPs), 46 odorant receptors (ORs), 20 gustatory receptors (GRs), 35 ionotropic receptors (IRs), 4 sensory neuron membrane proteins (SNMPs) and 4 different gene families encoding odorant-degrading enzymes (ODEs): 80 cytochrome P450s (CYPs), 12 esterase (ESTs), and 5 aldehyde dehydrogenases (ADE) were annotated in the D. citri antennal and abdominal transcriptomes. Our results revealed that a large proportion of chemosensory genes exhibited no distinct differences in their expression patterns in the antennae and terminal abdominal tissues. Notably, RNA sequencing (RNA-seq) data and quantitative real time-PCR (qPCR) analyses showed that 4 DictOBPs, 4 DictCSPs, 4 DictIRs, 1 DictSNMP, and 2 DictCYPs were upregulated in the antennae relative to that in terminal abdominal tissues. Furthermore, 2 DictOBPs (DictOBP8 and DictOBP9), 2 DictCSPs (DictOBP8 and DictOBP12), 4 DictIRs (DictIR3, DictIR6, DictIR10, and DictIR35), and 1 DictCYP (DictCYP57) were expressed at higher levels in the male antennae than in the female antennae. Our study provides the first insights into the molecular basis of chemoreception in this insect pest. Further studies on the identified differentially expressed genes would facilitate the understanding of insect olfaction and their role in the interactions between olfactory system and biological processes.

MeSH terms

  • Abdomen / physiology*
  • Animals
  • Arthropod Antennae / metabolism*
  • Citrus / parasitology*
  • Gene Expression Profiling
  • Gene Ontology
  • Genes, Insect*
  • Hemiptera / genetics*
  • Insect Proteins / genetics*
  • Insect Proteins / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Phylogeny
  • Real-Time Polymerase Chain Reaction
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / metabolism
  • Receptors, Odorant / genetics
  • Receptors, Odorant / metabolism
  • Reproducibility of Results
  • Sensory Receptor Cells / metabolism
  • Taste / genetics
  • Transcriptome / genetics*

Substances

  • Insect Proteins
  • Membrane Proteins
  • Receptors, Cell Surface
  • Receptors, Odorant
  • odorant-binding protein

Grants and funding

This work was supported financially by the special funds of scientific and technological development of Guangdong Province in 2016, China (Grant No. 2016B020202009 and 2016A040403118), and the Guangzhou scientific and technological project (Grant No. 201510010141)