Identification and analysis of Diaphorina citri female-specific genes

The Asian Citrus Psyllid, Diaphorina citri (D. citri), is an insect vector for the bacterium Canidatus Liberbacter asiaticus, which causes Huanglongbing (HLB), also known as citrus greening disease. HLB is the most devastating of all citrus diseases worldwide, and there is currently no effective control strategy. Our research provides insights into the insect’s biological processes through manual curation of the D.citri genome. Little information describing the female-related reproductive genes of D.citri is currently available. Fourteen D. citri female reproductive genes were identified through literature review. Annotation of these genes was completed using evidence from previously annotated D. citri gene models, short read RNA-Seq, long read Iso-Seq, and predicted gene models available in the Citrusgreening.org WebApollo genome browser. The amino acid sequences collected from pancreatic triacylglycerol lipase, Jagunal, and ecdysone receptor completed gene models show a high query coverage and percent identity with orthologs, indicating high conservation of these genes. However, comparative analysis of the amino acid sequences of vitellogenin-2, vitellogenin receptor, vitellogenin-1 and apolipoprotein indicate these genes are less conserved. Among Hemiptera, gene copy number is consistent for Bicaudal C, vitellogenin receptor, jagunal, and ecdysone receptor. Differences in copy number were observed for vitellogenin-1 (Vg-1), vitellogenin-2 and calmodulin. Analysis of RNA-Seq expression data shows that Vg-1 is highly expressed in D. citri females compared to males. Further analysis of genes related to reproduction that are differentially expressed in females may contribute to the development of molecular therapeutics to inhibit reproduction of the insect vector.