Location: Crop Bioprotection Research
2019 Annual Report
Objectives
Objective 1. Enable the commercial production of microorganisms pathogenic to mosquitoes.
Objective 2. Enable the commercial production of bioactive compounds/metabolites derived from plants and microorganisms to control mosquitoes and/or the viruses they carry.
Approach
Our approach will focus on the discovery of novel microbial and plant-based biopesticides that could be commercialized for the control of mosquitoes or the pathogens they transmit. A variety of entomopathogenic fungi will be evaluated for their effect on survival of adult mosquitoes. Selection of candidate mosquito entomopathogens will be done initially by focusing on the isolates with known pathogenicity and strains that have previously been isolated from dipteran species. Transcriptomic analysis coupled with functional assays (through reverse-genetic techniques) will be used to identify the fungal mode of action as well as the mosquito responses to infection. Attempts will be made to isolate and identify microbe-derived molecules with biological activity against mosquitoes and selected arboviruses. We will also evaluate plant-based compounds effective for activity against mosquitoes. We will integrate standard insecticide testing bioassays with modern and conventional approaches in chemical ecology to identify the chemical compounds in selected plants that are attractive to gravid females and deleterious to mosquito larvae.
Progress Report
Our research group focused on interdisciplinary studies to discover novel compounds from plants, bacteria, and fungi that are effective against mosquitoes and the diseases they transmit. Substantial progress has been made in the second year of this research project.
ARS scientists in Peoria, Illinois, made significant progress in Objective 1 by establishing how the type of host blood meal ingested by the mosquito influences the composition of microbial communities that inhabit the mosquito gut. Researchers also successfully completed studies that examined how the site of mosquito collection influences the composition and diversity of bacterial communities associated with mosquitoes. We also successfully evaluated the use of fluorescent proteins as markers for bacterial communities inhabiting the mosquito gut to facilitate the study of their functions. We successfully identified a previously unrecognized defense mechanism mounted by the mosquito to overcome infection by fungal entomopathogens. Additionally, we continued examining additional fungal entomopathogens for their virulence against Ae. aegypti, Ae. albopictus and Cx pipiens mosquitoes.
For Objective 2, we continued with studies on the potential to exploit common blackberry (Rubus allegheniensis) leaves as a tool for controlling mosquitoes in stormwater catch basins. These man-made aquatic habitats serve as the main larval habitats for the northern house mosquito, the primary vector of West Nile virus in northeastern United States. The study integrated a variety of conventional and modern technologies to better understand why leaf infusion of common blackberry is an attractive habitat for egg-laying mosquitoes, yet harmful to mosquito larvae. Because the results could not point to specific chemical compounds from blackberry leaves that were responsible for these bioactivities, the research was expanded to investigate the biological activity of various plant essential oils on mosquito eggs and larvae as outlined in the project plan. These studies have led to the identification of novel plant-based compounds that could be investigated for further development and commercialization as tools for mosquito control. We continued with the screening of entomopathogenic fungi with the potential to generate compounds with mosquitocidal and antimicrobial activity. Current efforts are focused on maximizing the production of bioactive metabolite by candidate fungi and identifying the best growing conditions during the fermentation process.
Accomplishments
1. Bacterial communities associated with mosquitoes. Bacterial communities associated with mosquitoes particularly those inhabiting the mosquito gut, play essential roles in mosquito biology. They support mosquito development, aid in blood meal digestion, and can even block transmission of disease-causing agents transmitted by mosquitoes such as malaria. ARS researchers in Peoria, Illinois, discovered that bacterial communities inhabiting the mosquito guts vary markedly based on mosquito species, site of mosquito collection and the type of host from which the mosquitoes ingested blood. Further studies revealed that fluorescent proteins could successfully be used as markers for some bacterial communities that reside in mosquito gut to allow detailed analysis of their behavior and functions in mosquito biology. Collectively, these findings advance current knowledge on microbial communities associated with mosquitoes and provide a methodology for additional studies on their functions without disturbing the normal gut microflora.
Review Publications
Muturi, E.J., Dunlap, C.A., Ramirez, J.L., Rooney, A.P., Kim, C. 2018. Host blood meal source has a strong impact on gut microbiota of Aedes aegypti. FEMS Microbiology Ecology. 95. https://doi.org/10.1093/femsec/fiy213.
Gardner, A.M., Muturi, E.J., Allan, B.F. 2018. Discovery and exploitation of a natural ecological trap for a mosquito disease vector. Proceedings of the Royal Society B. http://dx.doi.org/10.1098/rspb.2018.1962.
Parker, A.T., Gardner, A.M., Perez, M., Allan, B.F., Muturi, E.J. 2018. Container size alters the outcome of interspecific competition between Aedes aegypti (Diptera: Culicidae)and Aedes albopictus. Journal of Medical Entomology. https://doi.org/10.1093/jme/tjy215.
Ramirez, J.L., Muturi, E.J., Barletta-Ferreira, A.B., Rooney, A.P. 2018. The Aedes aegypti IMD pathway is a critical component of the mosquito antifungal immune response. Developmental and Comparative Immunology. https://doi.org/10.1016/j.dci.2018.12.010.
Muturi, E.J., Doll, K.M., Berhow, M.A., Weiler, L., Rooney, A.P. 2019. Honeysuckle essential oil as a potential source of ecofriendly larvicides for mosquito control. Pest Management Science. 75(7):2043-2048. https://doi.org/10.1002/ps.5327.
Muturi, E.J., Doll, K.M., Ramirez, J.L., Rooney, A.P. 2018. Bioactivity of wild carrot (Daucus carota, Apiaceae) essential oil against mosquito larvae. Journal of Medical Entomology. https://doi.org/10.1093/jme/tjy226.
Muturi, E.J., Ramirez, J.L., Kim, C. 2019. Green, yellow and red fluorescent proteins as markers for bacterial isolates from mosquito midguts. Insects. 10:49. https://doi.org/10.3390/insects10020049.
Kim, C., Muturi, E.J., Lee, S. 2018. Copula modeling of differential effect of leaf species on Aedes albopictus development time. Environment and Natural Resources Research. 8(4). https://doi.org/10.5539/enrr.v8n4p1.
Muturi, E.J., Lagos-Kutz, D.M., Dunlap, C.A., Ramirez, J.L., Rooney, A.P., Hartman, G.L., Fields, C., Rendon, G., Kim, C. 2018. Mosquito microbiota cluster by host sampling location. Parasites & Vectors. 11:468. https://doi.org/10.1186/s13071-018-3036-9.
Le, P.V., Kumar, P., Ruiz, M.O., Mbogo, C., Muturi, E.J. 2019. Predicting the direct and indirect impacts of climate change on malaria in coastal Kenya. PLOS One. 14:e0211258. https://doi.org/10.1371/journal.pone.0211258.
