Abstract：Corythucha ciliata is a major and specific pest of Platanus acerifolia. The objective of this study is to establish the antennal transcriptome database of the sycamore lace bug (Corythucha ciliata), and to obtain the olfactory-related genes in C. ciliata. The antennal transcriptome of male and female adults of C. ciliata was sequenced using Illumina HiSeqTM 4000 platform and bioinformatics analysis. A total of 65 943 Unigenes were obtained, with a mean length of 1 036 bp and an N50 of 1 809 bp. Through a similarity search, 16 600 Unigenes were annotated, most Unigenes (23.12%) were annotated to a database of orthologous groups of gene (eggNOG) database. All Unigenes against the NCBI Non-redundant Protein Sequences (Nr) database had the highest similarity (14.40%) with those of Zootermopsis nevadensis. Moreover, according to Gene Ontology (GO) database, 6 435 Unigenes were broadly divided into 52 branches of 3 categories: 16 271 Unigenes to be related to biological processes categories, 10 285 Unigenes related to cellular components, and 7 989 Unigenes related to molecular functions, and more Unigenes were annotated to be related to metabolic process, cellular process, catalytic activity and binding activity. Gene expression analysis showed that a total of 1 116 genes expressed differentially, involving in 1 096 genes up-regulated genes and 20 down-regulated genes. According to clusters of orthologous groups of proteins (KOG) database, 10 335 Unigenes were divided 25 categories, 2 515 and 1 233 Unigenes were related to general function prediction only and signal transduction mechanisms, respectively. By searching Kyoto Encyclopedia of Genes and Genomes (KEGG) database, 6 309 Unigenes were assigned to 255 metabolic pathways. Including 346 differentially expression genes, among these, the most genes (20) were involved in metabolic pathways of carbon. By further screening and identification, 194 olfactory-related genes of C. ciliata were obtained, including 77 odorant receptors (OR) genes, 64 odorant degrading enzymes (ODE) genes, 26 odorant binding proteins (OBP) genes, 11 ionotropic receptors (IR) genes, 14 chemosensory proteins (CSP) genes and 2 sensory neuron membrane proteins (SNMP) genes. A total of 65 943 Unigenes, 5 404 Unigenes with higher expression abundance (FPKM＞10) and 12 726 Unigenes with an FPKM (fragments per kilobase per million reads) value of 0. There were 2 OBP genes among the top 50 genes with higher expression abundance, and the highest expression level of OBP gene with an FPKM value of 953. This study preliminarily clarified the whole expression pattern of the antennal transcriptome of male and female adults of C. ciliata, which will provide a molecular foundation for further studying the mechanism of olfactory regulation of C. ciliata.
