Identification of potential transcriptomic biomarkers for varroa resistance in honey bees (apis mellifera anatoliaca)

Official URL: https://risc01.sabanciuniv.edu/record=b2767125_(Table of contents)

Honey bees are experiencing heavy mortality due to environmental stressors, pesticide exposure, and diseases. Since honey bees contribute significantly to the economy due to their roles as essential pollinators and producers of honey among many other products, increased mortality rates are severely affecting the global and Turkish economy. The lead cause of honey bee mortality and health decline is infestation of honey bee colonies with the ectoparasite Varroa destructor, also known as the Varroa mite. Several honey bee lines have been selectively bred for traits linked to low levels of Varroa mites for generations to generate Varroa-resistant (VR) lines around the globe. Here, we examine disease prevalence, abundance, and gene expression profiles of honey bee lines that have been selectively bred locally for low levels of Varroa mites to identify transcriptomic biomarkers for Varroa resistance. We identified 278 significantly upregulated and 23 downregulated genes in VR colonies. The top differentially expressed gene was the CCAAT/enhancer-binding protein gamma (LOC726550). Next, we queried significantly upregulated genes against STRING to build a protein-protein interaction network. Network topological features revealed its scale-free property, indicating that most genes are connected to a small number of the highly connected genes called hubs. Further inspection of the network revealed that the top two hubs, papilin (LOC413021) and heat shock protein cognate 4 (Hsc70-4), have high influence over the flow of information in the network, confirming their importance. Therefore, we suggest LOC413021, Hsc70-4, and LOC726550 as potential transcriptomic biomarkers for Varroa resistance.