Genomic identification, annotation, and comparative analysis of Vacuolar-type ATP synthase subunits in Diaphorina citri

Detailed annotation and comparative analysis were performed on the Asian citrus psyllid (ACP), Diaphorina citri, vacuolar-type ATP synthase (V-ATPase) to support the biological understanding and development of novel therapeutics to manage psyllid vectors. D. citri is a hemipteran insect that vectors the causative agent, the bacteria Candidatus Liberibacter asiaticus (CLas), of the citrus greening disease, Huanglongbing (HLB). Millions of citrus trees have been destroyed by citrus greening and every grove in Florida has been directly impacted. In eukaryotic organisms, V-ATPase is an abundant heterodimeric enzyme that serves the cell with essential compartment acidification through the active processes that transport protons across the membrane. Manual curation was completed on 15 putative V-ATPase genes in the D. citri genome. Comparative genomic analysis reveals that the D. citri V-ATPase subunits share domains and motifs with other insects, including the V-ATPase-A superfamily domain from the V-ATPase catalytic subunit A, which shares a 92% identity with Acyrthosiphon pisum. Phylogenetic analysis separates D. citri V-ATPase subunits into expected clades with orthologous sequences. Based on the results of annotation and comparative genomic analysis, RNAi therapies targeting D. citri V-ATPase genes, which have been successfully utilized in related hemipterans, are being pursued. Annotation of the D. citri genome is a critical step towards the development of directed-pest management that will lead to the reduced spread of the pathogens causing HLB throughout the citrus industry.