New players in honey bee immunity: the role of reactive nitrogen and oxygen species

Authors: JIRI, DANIHLIK - Palacky University; PETRIVALSKÝ, MAREK - Palacky University; Simone-Finstrom, Michael

Submitted to: Proceedings of Apimondia Congress
Publication Type: Abstract Only
Publication Acceptance Date: 9/15/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Honey bee immunity is influenced by many factors, such as pests and pathogens, pesticides, environment and also beekeeping practice. Beside the social immunity displayed by honey bees at the colony level, individual bees are also equipped with a complex network of closely interconnected cellular and humoral immunity. Similarly to previous observations on other insect species, reactive nitrogen (RNS) and oxygen (ROS) species have emerged as important players involved in molecular mechanisms of bee immunity. These highly reactive compounds are known to be involved in signalling cascades following the pathogen recognition and also as effector molecules providing antimicrobial action in immune responses on local and systemic levels. Within the insect epithelial immunity, upregulated production of ROS and nitric oxide (NO) in the early phase after pathogen infection stimulates expression of antimicrobial peptides through Toll signalling pathway as a part of local responses to invading microbes. Furthermore, ROS- and NO-signalling pathways interact within the activation of systemic responses through various components of cellular and humoral immunity, including the fat tissue and hemocytes. Actual knowledge about functions and importance of ROS and NO in honey bee immunity and health is quite limited. Our research combines biochemical, immunochemical and microscopic methods to study levels of ROS, NO and enzymes of their metabolism in bees or bee tissues challenged with relevant microbial pathogens. We have performed a detailed characterization of key enzymes of ROS metabolism, NADPH oxidase, superoxide dismutase and catalase, and of NO metabolism, nitric oxide synthase and S-nitrosoglutathione reductase, in bees infected with model bacterial pathogens. Furthermore, we initiated a pilot study on the role of ROS and RNS in bees infected with selected viruses. Finally, we aim to investigate how ROS- and NO-dependent immune mechanisms might be modulated by bee nutritional status or seasonal factors. The obtained results can contribute to further understanding of the regulatory and effector roles of ROS and RNS in mechanisms of bee tolerance or resistance to biotic stress factors.