Abstract: 【Aim】 This study aims to establish the adult antennal transcriptome database of Lytta caraganae, and explore and identify genes of olfactory-related odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) in its adult antennae. 【Methods】 Transcriptome analysis of adult antennae of L. caraganae was performed on Illumina HiSeq platform. Assembled genes were annotated by alignment against public databases NR, NT, KO, Pfam, Swiss-Prot, GO and KOG. OBP and CSP genes of L. caraganae were screened according to the annotation results. Structural characteristics and evolutionary relationship of OBP and 
CSP genes were analyzed by ClustalX 1.83 and MEGA 7.0 software, respectively. The expression levels of OBP and CSP genes in female and male adult antennae of of L. caraganae were determined by qRTPCR. 【Results】 A total of 51 028 transcripts and 41 998 unigenes were obtained from the adult antennal transcriptome of L. caraganae. Gene annotation results showed that L. caraganae genes have the highest match (87.3%) to those of Tribolium castaneum. Twenty-wo OBP genes and seven CSP genes were screened. Sequence alignment result showed that 13 LcarOBPs are classified into classic OBPs， which contain six conserved cysteine residues. Phylogenetic tree showed that LcarOBPs and LcarCSPs show the highest amino acid sequence identity with OBPs and CSPs of Hycleus cichorii and H. phaleratus, respectively, indicating the closest evolutionary relationship. qRT-PCR results showed that two LcarOBP genes and two LcarCSP genes were highly expressed in the male adult antennae of L. caraganae, while ten LcarOBP genes and two LcarCSP genes highly expressed in the female adult antennae. 【Conclusion】 The OBP and CSP genes in adult antennae of L. caraganae have been identified for the first time, providing a theoretical basis for further study on the mechanism of olfactory recognition in L. caraganae.

Key words:  Lytta caraganae, antennal transcriptome, olfactory recognition, odorant-binding protein, chemosensory protein