2012 Annual Report
To address our goal to “Develop microbial and arthropod natural enemies as biocontrol agents of insect pests of landscape plants” we characterized baculovirus (NPV) isolates in the IIBBL virus collection at molecular and genome sequence levels for use against gypsy moth (GM), the most serious U.S. landscape pest. Isolates from Korea, Japan, Russia, Spain, and Massachusetts were selected for characterization by complete genome sequencing. A complete draft of the Massachusetts genome and partial drafts of genomes for other isolates were produced. To develop an alternative to winter moth larvae for evaluating NPVs for WM control, we initiated a cell line from WM embryos from dissected and homogenized eggs.
We also identified a diverse group of non-crystal-forming Bacilli from forest soil that carried insecticidal toxin genes like those in Photorhabdus and Yersinia, but distinct from other bacteria. Multi-locus sequence typing analysis of B. thuringiensis populations (Bts) revealed great diversity even among close phylogenetic relatives. The majority of Bts belonged to few major phylogenetic groups. The distribution of crystal-forming Bacillus species from hardwood forests revealed a new group of mild pathogens related to B. weihenstephanensis which grow at low temperature. Sampling at different elevations revealed that these were dominant crystal-forming Bacilli on slopes and hilltops, but absent from floodplains. Floodplain soils were dominated by Bacilli belonging to an undescribed group producing trapezoidal crystals, which were occasionally toxic to GM.
To address our goal to “Identify genes and gene pathways critical for success of pests; employ molecular technologies to determine the role of host pathways targeted by entomopathogens; and target these pathways to kill pests” we conducted studies and analyzed transcriptome profiles to identify expressed genes in GM cell line Ld652Y and healthy 3rd instar larvae for both midgut and hemocyte tissues. Tissues were separately infected with Bt and other microbial pathogens, and parasitized by braconid parasitoid G. flavicoxis. Transcriptome profiles were generated for each to assess differences in levels of gene transcription between healthy and pathogen-infected tissues and to identify target genetic pathways. This will allow us to determine molecular vulnerabilities of GM to pathogens and parasitoids.
Dupuy, C., Gundersen, D.E., Cusson, M. 2012. Genomics and Replication of Polydnaviruses. In: Beckage, N.E., Drezen, J.M., editors. Parasitoid Viruses: Symbionts and Pathogens. London, England: Elsevier. p. 47-61.
Sparks, M., Gundersen, D.E. 2011. The Lymantria dispar IPLB-Ld652Y cell line transcriptome comprises diverse virus-associated transcripts. Viruses. 3(11): 2339-2350.
Bergh, J.C., Zhang, A., Meyer, J.R., Kim, D. 2011. Response of grape root borer (lepidoptera: sesiidae) neonates to root extracts from vitaceae species and rootstocks. Environmental Entomology. 40:880-888.
Cha, D., Linn, C., Teal, P.E., Zhang, A., Roelofs, W., Loeb, G. 2011. Eaves-dropping on plant volatiles by a specialist moth: significance of ratio and concentration. PLoS One. 6(2):e17033.
Crook, D., Khrimian, A., Cosse, A.A., Frazer, I., Mastro, V. 2012. Influence of trap color and host volatiles on capture of the emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae). Journal of Environmental Entomology. 105:429-437.
Loeb, G., Cha, D., Hesler, S., Linn, C., Zhang, A., Teal, P.E., Roelofs, W. 2011. Monitoring grape berry moth (Paralobesia vitianna: Lepidoptera) in commercial vineyards using a host plant based synthetic lure. Environmental Entomology. 4(6):1511-1522.
Martin, P.A., Mongeon, P., Gundersen, D.E., Blackburn, M.B. 2011. Recovery of Bacillus thuringiensis and insect toxic related strains from forest soil. Applied and Environmental Microbiology. 2(7):285-291.
Tobin, P.C., Zhang, A., Onufrieva, K., Leonard, D.S. 2011. A field evaluation of the effect of temperature on the release of disparlure from a pheromone-baited trapping system used to monitor the gypsy moth (Lepidotera: Lymantriidae). Journal of Economic Entomology. 104(4):1265-1271.
Frank, D., Zhang, A., Leskey, T.C., Bergh, J. 2011. Electrophysiological response of female dogwood borer (lepidoptera: sesiidae) to apple volatile compounds. Journal of Entomological Science. 46(3):204-215.
Greenstone, M.H., Weber, D.C., Hu, J.S., Coudron, T.A., Payton, M.E. 2012. Removing external DNA contamination from arthropod predators destined for molecular gut-content analysis. Molecular Ecology Resources. 12(3):464-469.