Location: Carl Hayden Bee Research Center
Project Number: 2022-21000-021-004-I
Project Type: Interagency Reimbursable Agreement
Start Date: Jan 1, 2021
End Date: Dec 31, 2024
European honey bees (Apis mellifera) are beneficial insects that provide essential pollination services for agriculture and ecosystems worldwide. Modern commercial beekeeping is faced with a variety of pathogenic and environmental stressors often confounding attempts to understand colony loss. European foulbrood (EFB) is a larval disease whose causative agent, Melissococcus plutonius, has received limited attention due to methodological challenges in the field and laboratory. As a confounding factor, many disease phenotypes classified as EFB or EFB-like cannot be attributed to M. plutonius. Here we propose to improve the experimental and informational context of larval microbiota with the end goal of developing diagnoses and management strategies for known and idiopathic brood disease. Our objectives are to: 1) sequence the microbiota associated with larval health and disease, including potential transmission routes, 2) Isolate, characterize and whole genome sequence major disease related microbial strains and determine their virulence against larvae in vitro, 3) Use multi-locus sequence typing to identify and track the spread of virulent bacteria, virulence genes and clonal groups both regionally and throughout the USA, and 4) Improve field and lab assays for the diagnosis of larval disease types.
Key approaches for this project will be high throughput analysis of bacterial, fungal and viral microbiomes from healthy and diseased hives. Detailed photographs both visibly diseased and “non-diseased” areas of the colony, noting diagnostic characteristics associated with the disease state and non-diseased state. Broad field sampling of brood disease outbreaks throughout Illinois and Michigan in collaboration with apiary inspectors and extension agents. Collaboration with Belltsville to analyze samples sent for diagnostic analysis. Whole genome sequencing of approximately 100-150 bacteria involved in larval health and disease. This data will be used to design in vitro larval experiments exploring virulence and susceptibility focused primarily on European foul brood disease and novel disease agents (M. plutonius). Strains will be isolated from active outbreaks of brood disease throughout the US. Phylogenetic relationships and diversity will be determined by whole genome phylogeny analysis using an allele-based whole genome multi-locus sequence analysis (MLST) or core genome MLST analysis (cgMLST). This work will establish the first genomic dataset of bacterial strains associated with brood disease, and their potential for disease both alone and in combination. This data will be used to improve diagnostic capability and track the recurrence and emergence of new strains, and improve the diagnosis of larval disease, both known and discovered, that may impact honey bee health.