Diaci V3.0: Chromosome-level Assembly, De Novo Transcriptome, and Manual Annotation of Diaphorina Citri, Insect Vector of Huanglongbing

Background: Diaphorina citri is an insect vector of "Candidatus Liberibacter asiaticus" (CLas), the gram-negative bacterial pathogen associated with citrus greening disease. Control measures rely on pesticides with negative impacts on the environment, natural ecosystems, and human and animal health. In contrast, gene-targeting methods have the potential to specifically target the vector species and/or reduce pathogen transmission.

Results: To improve the genomic resources needed for targeted pest control, we assembled a D. citri genome based on PacBio long reads followed by proximity ligation-based scaffolding. The 474-Mb genome has 13 chromosomal-length scaffolds. In total, 1,036 genes were manually curated as part of a community annotation project, composed primarily of undergraduate students. We also computationally identified a total of 1,015 putative transcription factors (TFs) and were able to infer motifs for 337 TFs (33%). In addition, we produced a genome-independent transcriptome and genomes for D. citri endosymbionts.

Conclusions: Manual annotation provided more accurate gene models for use by researchers and provided an excellent training opportunity for students from multiple institutions. All resources are available on CitrusGreening.org and NCBI. The chromosomal-length D. citri genome assembly serves as a blueprint for the development of collaborative genomics projects for other medically and agriculturally significant insect vectors.