title: Annotation of the Asian Citrus Psyllid Genome Reveals a Reduced Innate Immune System.
abstract: Citrus production worldwide is currently facing significant losses due to citrus greening disease, also known as Huanglongbing. The citrus greening bacteria,CandidatusLiberibacter asiaticus (CLas), is a persistent propagative pathogen transmitted by the Asian citrus psyllid,Diaphorina citriKuwayama (Hemiptera: Liviidae). Hemipterans characterized to date lack a number of insect immune genes, including those associated with the Imd pathway targeting Gram-negative bacteria. TheD. citridraft genome was used to characterize the immune defense genes present inD. citri. Predicted mRNAs identified by screening the publishedD. citriannotated draft genome were manually searched using a custom database of immune genes from previously annotated insect genomes. Toll and JAK/STAT pathways, general defense genes Dual oxidase, Nitric oxide synthase, prophenoloxidase, and cellular immune defense genes were present inD. citri. In contrast,D. citrilacked genes for the Imd pathway, most antimicrobial peptides, 1,3-β-glucan recognition proteins (GNBPs), and complete peptidoglycan recognition proteins. These data suggest thatD. citrihas a reduced immune capability similar to that observed inA. pisum, P. humanus, andR. prolixus. The absence of immune system genes from theD. citrigenome may facilitateCLas infections, and is possibly compensated for by their relationship with their microbial endosymbionts.
authors.affiliation: Citrus Research and Education Center, Department of Entomology and Nematology, University of Florida Fort Pierce, FL, USA.
authors.forename: Alex P
authors.initials: AP
authors.lastname: Arp
authors.affiliation: U.S. Horticultural Research Lab, Agricultural Research Service, United State Department of Agriculture Fort Pierce, FL, USA.
authors.forename: Wayne B
authors.initials: WB
authors.lastname: Hunter
authors.affiliation: Citrus Research and Education Center, Department of Entomology and Nematology, University of Florida Fort Pierce, FL, USA.
authors.forename: Kirsten S
authors.initials: KS
authors.lastname: Pelz-Stelinski
keywords: Diaphorina citri; Imd; antimicrobial peptide; genes; immune; liberibacter; virus