Biomarkers of disease resistance identified by quantitative proteomics

Honey bees (Apis mellifera) are complex eusocial insects that play a critical role in human agriculture and food production. In response to a wide range of pathogens that affect honey bees, such as the parasitic mite Varroa destructor, the bacteria P. larvae, fungus and viruses, these insects have evolved a variety of individual and colony-level mechanisms to confer resistance. The ability of honey bees to resist infection can be enhanced by selective breeding. To facilitate this process, we are identifying biomarkers associated with disease resistance traits that can be used in marker assisted selection (MAS). MAS has been proven to be effective in many sectors of agriculture, but it has yet to be applied in honey bee selective breeding. We use quantitative mass spectrometry-based proteomics, a powerful tool to identify differences in the level of proteins between samples. The comparative proteome profiling of honey bee antennal samples resulted in the relative quantitation of ~1000 proteins. Using a Linear Mixed-Effects Model, we found protein clusters associated with the population of origin of the honey bees and, more interestingly, proteins associated with hygienic behavior independent of population. Hygienic behavior is a well defined colony level resistance trait characterized by the rapid removal of diseased or dead larvae by nurse bees. We are currently analyzing protein levels in other samples, particularly those of larvae, to identify biomarkers associated with other resistance traits. Heritability studies of the disease resistant traits and their biomarkers will also be discussed.