„In the past decade, honey bee populations have experienced severe and persistent losses across the Northern Hemisphere, mainly due to the effects of pathogens, such as fungi and viruses,“ said Vincent Doublet, who coordinated the research at sDiv, the synthesis centre of the German Centre for Integrative Biodiversity Research (iDiv) and is now a postdoctoral research fellow at the University of Exeter. „The genes that we identified offer new possibilities for the generation of honey bee stocks that are resistant to these pathogens.“ An essential part played two workshops organized by sDiv in 2013/14 where the international research team met in Leipzig as part of the „TRANs-BEE“ project.
According to the researchers, recent advances in DNA sequencing have prompted numerous investigations of the genes involved in honey bee responses to pathogens. Yet, until now, this vast quantity of data has been too cumbersome and idiosyncratic to reveal overarching patterns in honey bee immunity.
„While many studies have used genomic approaches to understand how bees respond to viruses and parasites, it has been difficult to compare across these studies to find the core genes and pathways that help the bee fight off stressors,“ said Christina Grozinger, Distinguished Professor of Entomology, Penn State. „Our team created a new bioinformatics tool that has enabled us to integrate information from 19 different genomic datasets to identify the key genes involved in honey bees’ response to diseases.“
Specifically, the team of 28 researchers, representing eight countries, created a new statistical technique, which they termed directed rank-product analysis. The technique allowed them to identify the genes that were expressed similarly across the 19 datasets, rather than just the genes that were expressed more than others within a dataset.
The scientists found that these similarly expressed genes included those that encode proteins responsible for the response to tissue damage by pathogens, and those that encode enzymes involved in the metabolism of carbohydrates from food, among many others. A decrease in the latter, they suggested, may illustrate the cost of the infection on the organism.
„Honey bees were thought to respond to different disease organisms in entirely different ways, but we have learned that they mostly rely on a core set of genes that they turn on or off in response to any major pathogenic challenge,“ said Robert Paxton, professor of zoology at the Martin Luther University Halle-Wittenberg and a member of iDiv. „We can now explore the physiological mechanisms by which pathogens overcome their honey bee hosts, and how honey bees can fight back against those pathogens.“
The implications of the findings are not limited to honey bees. The team found that the core genes are part of conserved pathways — meaning they have been maintained throughout the course of evolution among insects and therefore are shared by other insects. According to Doublet, this means that the genes provide important knowledge for understanding pathogen interactions with other insects, such as bumble bees, and for using pathogens to control insect pests, such as aphids and certain moths.
„This analysis provides unprecedented insight into the mechanisms that underpin the interactions between insects and their pathogens,“ said Doublet. „With this analysis, we generated a list of genes that will likely be an important source for future functional studies, for breeding more resilient honey bee stocks and for controlling emerging bee diseases.“
This research was supported by iDiv, the German Center for Integrative Biodiversity Research, located in Leipzig, Germany.
Vincent Doublet, Yvonne Poeschl, Andreas Gogol-Döring, Cédric Alaux, Desiderato Annoscia, Christian Aurori, Seth M. Barribeau, Oscar C. Bedoya-Reina, Mark J. F. Brown, James C. Bull, Michelle L. Flenniken, David A. Galbraith, Elke Genersch, Sebastian Gisder, Ivo Grosse, Holly L. Holt, Dan Hultmark, H. Michael G. Lattorff, Yves Le Conte, Fabio Manfredini, Dino P. McMahon, Robin F. A. Moritz, Francesco Nazzi, Elina L. Niño, Katja Nowick, Ronald P. van Rij, Robert J. Paxton and Christina M. Grozinger (2017): Unity in defence: honeybee workers exhibit conserved molecular responses to diverse pathogens. BMC Genomics, Open Access online, 02 Mar 2017. doi: 10.1186/s12864-017-3597-6
This study was supported by sDiv, the Synthesis Centre for Biodiversity Sciences within the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, funded by the German Science Foundation (FZT 118). New datasets were performed thanks to the Insect Pollinators Initiative (IPI grant BB/I000100/1 and BB/I000151/1), with participation of
640 the UK-USA exchange funded by the BBSRC BB/I025220/1. The IPI is funded jointly by the Biotechnology and Biological Sciences Research Council, the Department for Environment, Food and Rural Affairs, the Natural Environment Research Council, the Scottish Government and the Wellcome Trust, under the Living with Environmental Change Partnership.
sDiv working group TRANs-BEE (Synthesising transcriptome data to explore interspecies bee-pathogen molecular interactions that may underpin pollinator decline)
Dr. Vincent Doublet (English)
siDiv – Synthesis Centre of the German Centre for Integrative Biodiversity Research (iDiv)
now: University of Exeter (UK)
Prof. Christina Grozinger (English)
Distinguished Professor of Entomology & Director, Center for Pollinator Research
Penn State University (Pa., USA)
Prof. Robert Paxton (English, German)
Professor for General Zoology at the Martin Luther University Halle-Wittenberg
as well as
Tilo Arnhold (English, German)
Tel.: +49 341 9733 109
iDiv is a central facility of Leipzig University within the meaning of Section 92 (1) of the Act on Academic Freedom in Higher Education in Saxony (Sächsisches Hochschulfreiheitsgesetz, SächsHSFG). It is run together with the Martin Luther University Halle-Wittenberg and the Friedrich Schiller University Jena, as well as in cooperation with the Helmholtz Centre for Environmental Research – UFZ.
The following non-university research institutions are involved as cooperation partners: the Helmholtz Centre for Environmental Research – UFZ, the Max Planck Institute for Biogeochemistry (MPI BGC), the Max Planck Institute for Chemical Ecology (MPI CE), the Max Planck Institute for Evolutionary Anthropology (MPI EVA), the Leibniz Institute DSMZ–German Collection of Microorganisms and Cell Cultures, the Leibniz Institute of Plant Biochemistry (IPB), the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) and the Leibniz Institute Senckenberg Museum of Natural History Görlitz (SMNG).