关键词: 沟眶象, 臭椿沟眶象, 转录组, 气味受体, 表达谱, 非嗅觉组织

Abstract: 【Aim】 To complement the odorant receptor (OR) information of two sibling species of Eucryptorrhynchus, E. scrobiculatus and E. brandti, and to provide theoretical basis for subsequent functional studies by the identification and expression profile analysis of OR genes based on the transcriptome data of these two weevil species at different developmental stages. 【Methods】 The OR gene sequences were screened from the transcriptome databases of different developmental stages of E. scrobiculatus (larva, pupa and adult) and E. brandti (egg, larva, pupa and adult). Interspecific and intraspecific sequence alignments of the screened ORs were performed based on the antennal transcriptome data of the two weevil species. Phylogenetic analysis of the newly identified OR genes was performed using the maximum likelihood method. Expression abundance analysis was performed according to FPKM (fragments per kilobase per million mapped fragments) values of the newly identified OR genes in the transcriptomes of two weevil species at different developmental stages. The expression profiles of the newly identified OR genes at different developmental stages and in different adult tissues of E. scrobiculatus and E. brandti were detected by qPCR. 【Results】 Six and four OR genes with complete open reading frames were identified from the transcriptome databases of different developmental stages of E. scrobiculatus and E. brandti, respectively. According to the sequence alignment results with the antennal transcriptome data, four (EscrOR50-53) and two (EbraOR46-47) OR genes were newly identified from E. scrobiculatus and E. brandti, respectively. We also found a pair of potential homologous genes, EscrOR53 and EbraOR45, between the two weevil species. The phylogenetic tree indicated that the six newly identified ORs belong to the subfamilies 2B and 7 of coleopteran ORs. According to the FPKM data of the transcriptomes of different developmental stages of the two weevil species and the spatiotemporal expression profiles detected by qPCR, three of the newly identified OR genes of E. scrobiculatus and the two newly identified OR genes of E. brandti were all highly expressed in non-olfactory tissues of adults, and also expressed in egg, larval or pupal stages. 【Conclusion】 In this study, the OR genes and their spatiotemporal expression profiles in the transcriptomes of different developmental stages of E. scrobiculatus and E. brandti have been clarified, and it is found that non-olfactory functional ORs possibly exist in the reproductive organs, suggesting that they may play a role in the early stage of development.

Key words: Eucryptorrhynchus scrobiculatus, Eucryptorrhynchus brandti, transcriptome, odorant receptor, expression profile, non-olfactory tissue