title: Regional variation in composition and antimicrobial activity of US propolis against Paenibacillus larvae and Ascosphaera apis.
abstract: Propolis is a substance derived from antimicrobial plant resins that honey bees use in the construction of their nests. Propolis use in the hive is an important component of honey bee social immunity and confers a number of positive physiological benefits to bees. The benefits that bees derive from resins are mostly due to their antimicrobial properties, but it is unknown how the diversity of antimicrobial activities among resins might impact bee health. In our previous work, we found that resins from different North American Populus spp. differed in their ability to inhibit in vitro growth of the bee bacterial pathogen Paenibacillus larvae. The goal of our current work was to characterize the antimicrobial activity of propolis from 12 climatically diverse regions across the US against the bee pathogens P. larvae and Ascosphaera apis and compare the metabolite profiles among those samples using LC-MS-based metabolomic methods. Samples differed greatly in their ability to inhibit both bacterial and fungal growth in vitro, but propolis from Nevada, Texas, and California displayed high activity against both pathogens. Interestingly, propolis from Georgia, New York, Louisiana, and Minnesota were active against A. apis, but not very active against P. larvae. Metabolomic analysis of regional propolis samples revealed that each sample was compositionally distinct, and LC-FTMS profiles from each sample contained a unique number of shared and exclusive peaks. Propolis from Aspen, CO, Tuscon, AZ, and Raleigh, NC, contained relatively large numbers of exclusive peaks, which may indicate that these samples originated from relatively unique botanical sources. This is the first study to characterize how the diversity of bee preferred resinous plants in the US may affect bee health, and could guide future studies on the therapeutic potential of propolis for bees.
authors.affiliation: Department of Entomology, University of Minnesota, 219 Hodson Hall, 1980 Folwell Ave, St. Paul, MN 55108, USA. Electronic address: wils0888@umn.edu.
authors.forename: M B
authors.initials: MB
authors.lastname: Wilson
authors.affiliation: Department of Horticultural Science, University of Minnesota, 305 Alderman Hall, 1970 Folwell Ave, St. Paul, MN 55108, USA. Electronic address: brin0094@umn.edu.
authors.forename: D
authors.initials: D
authors.lastname: Brinkman
authors.affiliation: Department of Entomology, University of Minnesota, 219 Hodson Hall, 1980 Folwell Ave, St. Paul, MN 55108, USA. Electronic address: spiva001@umn.edu.
authors.forename: M
authors.initials: M
authors.lastname: Spivak
authors.affiliation: Department of Horticultural Science, University of Minnesota, 305 Alderman Hall, 1970 Folwell Ave, St. Paul, MN 55108, USA; Microbial and Plant Genomics Institute, University of Minnesota, USA. Electronic address: ggardner@umn.edu.
authors.forename: G
authors.initials: G
authors.lastname: Gardner
authors.affiliation: Department of Horticultural Science, University of Minnesota, 305 Alderman Hall, 1970 Folwell Ave, St. Paul, MN 55108, USA; Microbial and Plant Genomics Institute, University of Minnesota, USA. Electronic address: cohen047@umn.edu.
authors.forename: J D
authors.initials: JD
authors.lastname: Cohen
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001203:Ascomycota / Q000187:drug effects / Q000502:physiology*; D001516:Bees / Q000382:microbiology*; D005843:Geography; D054884:Host-Pathogen Interactions / Q000187:drug effects; D007814:Larva / Q000187:drug effects / Q000502:physiology; D008826:Microbial Sensitivity Tests; D056507:Paenibacillus / Q000187:drug effects / Q000502:physiology*; D011429:Propolis / Q000494:pharmacology*
chemical_list: D000890:Anti-Infective Agents; D011429:Propolis
keywords: Apis mellifera; Ascosphaera apis; Honey bees; Paenibacillus larvae; Propolis; Resin