Location: Bee Research Laboratory
Project Number: 8042-21000-291-053-I
Project Type: Interagency Reimbursable Agreement
Start Date: Jan 1, 2022
End Date: Dec 31, 2025
This project will focus on the emergent honey bee parasite Lotmaria passim. The overall objective is to characterize strains of this parasite, determine virulence to bees, and use genomic tools to identify targets for novel medicines. Objective 1 is to Isolate and culture parasite strains from every continent except Antarctica. Objective 2 is to sequence and annotate the genomes of each isolate from Obj. 1-- including one high-quality, chromosome-level reference genome assembly using state-of-the-art long-read sequencing technology-- to quantify geographic differences, infer patterns and timing of parasite spread, and identify gene-specific selection, gene function, and structure of essential proteins. Objective 3 is to evaluate host-parasite genotypic specificity of infection to ascertain how parasite strains vary in infectivity, how bee lineages vary in resistance, and the genomic, transcriptomic, and microbiome predictors of infection outcome. Objective 4 is to develop transgenic lines expressing fluorescent and luminescent reporters for high-throughput screening of candidate treatments. Objective 5 is to develop genome-enabled treatments that reduce infection by targeting essential parasite genes. This Objective will use parasite genome data (Obj. 2) to identify target genes and corresponding sequences, which will be used to synthesize customized double-stranded RNA molecules that disrupt parasite gene expression. Effects on the parasite in vitro and the most promising candidates will be subject to follow-up trials in colonies.
Objective 1 requires worldwide shipped samples of L. passim and will also exploit samples collected as part of the National Honey Bee Disease Survey. With collaboration form ISU, samples will be processed to isolate parasite cells from honey bee cells and gut microbes to ensure accurate sequencing. Objective 2 will depend on a high-quality reference genome for L. passim, generated by PacBio long-read sequencing, and assembly facilitated by Hi-C physical mapping. Objective 3 will compare infection by 10 geographically diverse parasite strains in 5 commercially available bee genotypes. These experiments will also include genetic and transcriptomic analyses and microbiome profiling, providing a mechanistic basis for the observed infection outcomes. Objective 4 will use standard techniques to modify the L. passim genome to include a promoter-based signaling system. Objective 4 will use known lethal genes oin other trypanosomes, the genome data collected here, and dsRNA technology to design and test gene knockdown controls using RNA interference.