Characterization of Wnt Signaling Genes in Diaphorina citri, Asian citrus psyllid

Abstract

The Asian citrus psyllid, Diaphorina citri, is an insect vector that transmits Candidatus Liberibacter asiaticus, the causal agent of the Huanglongbing (HLB) or citrus greening disease. This disease has devastated Floridas citrus industry and threatens Californias industry as well as other citrus producing regions around the world. To find novel solutions to the disease, a better understanding of the vector is needed. The D. citri genome has been used to identify and characterize genes involved in Wnt signaling pathways. Wnt signaling is utilized for many important biological processes in metazoans, such as patterning and tissue generation. Curation based on RNA sequencing data and sequence homology confirm twenty four Wnt signaling genes within the D. citri genome, including homologs for beta-catenin, Frizzled receptors, and seven Wnt-ligands. Through phylogenetic analysis, we classify D. citri Wnt-ligands as Wg/Wnt1, Wnt5, Wnt6, Wnt7, Wnt10, Wnt11, and WntA. The D. citri version 3.0 genome with chromosomal length scaffolds reveals a conserved Wnt1-Wnt6-Wnt10 gene cluster with gene configuration similar to that in Drosophila melanogaster. These findings provide a greater insight into the evolutionary history of D. citri and Wnt signaling in this important hemipteran vector. Manual annotation was essential for identifying high quality gene models. These gene models can further be used to develop molecular systems, such as CRISPR and RNAi, that target and control D. citri populations, to manage the spread of HLB. Manual annotation of Wnt signaling pathways was done as part of a collaborative community annotation project (https://citrusgreening.org/annotation/index).