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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Crop Bioprotection Research » Research » Publications at this Location » Publication #425015
Research Project: Discovery and Production of Beneficial Microbes for Control of Agricultural Pests through Integration into Sustainable Agricultural Production Systems

Location: Crop Bioprotection Research

Title: Characterization of toxin systems of Paenibacillus strains isolated from honeybees

Author
item PANNULLO, ANTHONY - Orise Fellow
item Muturi, Ephantus
item Dunlap, Christopher

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2025
Publication Date: 8/26/2025
Citation: Pannullo, A., Muturi, E.J., Dunlap, C.A. 2025. Characterization of toxin systems of Paenibacillus strains isolated from honeybees. Scientific Reports. https://doi.org/10.1038/s41598-025-12956-x.
DOI: https://doi.org/10.1038/s41598-025-12956-x

Interpretive Summary: Honeybees and other pollinators play critical roles in our agricultural systems. It is important to understand the roles of the microorganisms that are closely associated with them. In this study, we sequenced the genomes of microorganisms that were found in dead honeybee larvae. Previous studies suggest that these strains were not pathogens of honeybees. However, this study, has discovered that the genomes of these microorganisms contain many toxin systems that are known to kill insects. Future studies are needed to determine how these microbes influence the health of honeybees and other pollinators, and to evaluate their potential application as biological control agents for insect pests.

Technical Abstract: Paenibacillus is a large genus of Gram-positive bacteria isolated from a wide range of sources. Members of this genus have attracted significant research as plant growth promoters as well as pathogens of both plants and animals. Extensive studies have been conducted on Paenibacillus larvae, the causative agent of American Foul Brood in honeybees, but little is known about other closely related species associated with honeybees, such as Paenibacillus apiarius or Paenibacillus thiaminolyticus. These bacterial species have been isolated from dead honeybee larvae and are believed to be secondary invaders as opposed to primary pathogens. We utilized genome mining efforts to explore the number and diversity of toxins present in multiple species of Paenibacillus, with major emphasis on a potentially entomopathogenic clade that includes Paenibacillus alvei, P. apiarius, and P. thiaminolyticus. Our results show that strains of these species contain a variety of potentially insecticidal toxins, including highly conserved Spp-like and Mpp-like toxins. These toxins are absent in P. larvae. We also found several ADP-ribosylases which were shared between P. larvae and several strains from this entomopathogenic clade. Tc toxins, a class of insecticidal toxin not often found in Gram-positive bacteria were found in P. apiarius and P. alvei. These findings suggest the potential for Paenibacillus species in this clade to be harnessed as sources of host specific and pollinator-friendly biopesticides.