Analysis of olfactory related genes in Batocera rufomaculata based on transcriptome

【Objective】The olfactory related genes in Batocera rufomaculata were identified and the differentially expressed genes （DEGs） were screened to provide theoretical support for the exploration of olfactory mechanism and new approaches to biological control of B. rufomaculata based on olfactory recognition. 【Method】The transcriptome sequences of antennae， tarsus and the body without antennae and tarsus of B. rufomaculata were sequenced using Illumina NovaSeq 6000 sequencing. Bioinformatics analysis methods such as sequencing data assembly， annotation， database sequence retrieval， sequence alignment and differential gene analysis were used to mine olfactory related genes. 【Result】In total， 137405 unigenes were obtained by transcriptome sequencing with an average length of 774 bp， N50 of 1462 bp，and GC content of 42.93%. Through homologous alignment， a total of 289 olfactory related genes were identified， including 45 OBPs， 22 CSPs， 50 ORs， 20 IRs， 26 GRs， 7 SNMPs， 8 CXEs， 82 CYPs， 19 AOXs， 10 GSTs genes. By comparing the transcriptome of all samples，a total of 8861 DEGs were screened，of which 2713 were up-regulated and 6148 were down-regulated. The results of gene function annotation and pathway enrichment analysis showed that 3613 DEGs were annotated to the biological process， cellular component and molecular function of GO function， among which the biological process accounted for the highest proportion （34.87%）. A total of 4002 DEGs were annotated to the KEGG database and involved in 96 pathways. Further analysis of olfactory related genes showed that 114 olfactory genes expression were significantly different， of which 79 were up-regulated and 35 were down-regulated. The expression levels of OBP22， OBP29， CSP10， CSP15， SNMP1，OR41， CXE2 and CYP10 genes in antennae were higher than those in other tissues. CSP10 and CSP15 genes were preferentially expressed in females. CYP34 gene was preferentially expressed in males and highly expressed in the tarsus. 【Conclusion】Olfactory related genes in B. rufomaculata such as OBPs， CSPs， ORs， IRs， GRs， SNMPs， CXEs， CYPs， AOXs， and GSTs are screened. It is speculated that the highly expressed OBPs and CSPs genes in the antennae play a crucial role in the recognition of pheromones released by the opposite sex of the same species or volatiles released by host plants. The CSPs gene that are preferentially expressed in females may play an important role in the process of females looking for oviposition sites.