Hemipterans include some of the most important insect pests of agricultural systems and vectors of plant pathogens. The vector, Diaphorina citri (Asian citrus psyllid) belonging to the Psylloidae superfamily, is the primary target of approaches to stop the spread of the pathogen Ca. Liberibacter asiaticus that causes Huanglongbing or citrus greening disease. High quality genomic resources enable rapid functional discovery that can target disease transmission and control. The previous psyllid genome (Diaci v1.1) available in NCBI is missing 25% of the single copy markers conserved in other Hemipterans. Manual genome curation helped to identify a significant number of genome anomalies including misassemblies and missing genes. We present an improved and highly contiguous de novo assembly based on PacBio long reads followed by Dovetail Chicago and Hi-C based scaffolding. The current assembly (Diaci v3) has 13 chromosomal length scaffolds with a genome size of 475 Mb. This is the first report of a chromosomal length assembly in the Hemiptera order according to our knowledge. Full-length cDNA transcripts were sequenced with PacBio Iso-Seq technology from diseased and healthy tissue at multiple life stages. Iso-Seq along with diverse Illumina RNA-Seq expression data were used to predict 19,049 protein-coding genes in psyllid using MAKER annotation pipeline. We also generated a genome independent transcriptome with a comprehensive catalog of all genes in the psyllid.

Citrus greening disease is caused by the pathogen Candidatus Liberibacter asiaticus and transmitted by the Asian citrus psyllid, Diaphorina citri. No curative treatment or significant prevention mechanism exists for this disease, which causes economic losses from reduced citrus production. A high-quality genome of D. citri is being manually annotated to provide accurate gene models to identify novel control targets and increase understanding of this pest.Here, we annotated 25 D. citri genes involved in glycolysis and gluconeogenesis, and seven in trehaloneogenesis. Comparative analysis showed that glycolysis genes in D. citri are highly conserved but copy numbers vary. Analysis of expression levels revealed upregulation of several enzymes in the glycolysis pathway in the thorax, consistent with the primary use of glucose by thoracic flight muscles. Manually annotating these core metabolic pathways provides accurate genomic foundation for developing gene-targeting therapeutics to control D. citri. SubjectsGenetics and Genomics, Animal Genetics, Bioinformatics DATA DESCRIPTION Background Huanglongbing (HLB), or citrus greening disease, is the biggest global threat to the citrus industry throughout the world [1]. The phloem-limited bacterial pathogen Candidatus Liberibacter asiaticus (CLas) is the causative agent of HLB. Upon infection of a citrus tree,

Citrus greening disease is caused by the pathogen Candidatus Liberibacter asiaticus, which is transmitted by the Asian citrus psyllid, Diaphorina citri. There is no curative treatment or significant prevention mechanism for this detrimental disease that causes continued economic losses from reduced citrus production. A high quality genome of D. citri is being manually annotated to provide accurate gene models required to identify novel control targets and increase understanding of this pest. Here, we annotated genes involved in glycolysis, gluconeogenesis, and trehaloneogenesis in the D. citri genome, as these are core metabolic pathways and suppression could reduce this pest. Specifically, twenty-five genes were identified and annotated in the glycolysis and gluconeogenesis pathways and seven genes for the trehaloneogenesis pathway. Comparative analysis showed that the glycolysis genes in D. citri are highly conserved compared to orthologs in other insect systems, but copy numbers vary in D. citri. Expression levels of the annotated gene models were analyzed and several enzymes in the glycolysis pathway showed high expression in the thorax. This is consistent with the primary use of glucose by flight muscles located in the thorax. A few of the genes annotated in D. citri have been targeted for gene knockdown as a proof of concept, for RNAi therapeutics. Thus, manual annotation of these core metabolic pathways provides accurate genomic foundations for developing gene-targeting therapeutics to reduce D. citri.