Location: Crop Bioprotection Research
2017 Annual Report
Objectives
1. Demonstrate production potential for baculovirus for insect control (such as black cutworm MNPV), evaluate formulations for storage stability and residual efficacy, and identify and evaluate insect semiochemicals such as attractants or feeding stimulants that can be integrated into formulations to improve control of major insect pests of turf or other crops.
2. Determine the relationship between microbial communities and the characteristics of weeds (such as bindweed, medusahead grass, or quack grass) that make them harmful to turf, natural ecosystems, and agricultural commodities.
3. Identify viruses that can target potential key endophytes or microorganisms that contribute negative characteristics of weeds.
4. Identify, describe, and preserve microorganisms isolated from weeds as part of the characterization of microbial communities associated with important weeds.
Approach
Grasses planted as turf and pasture represent a commodity that has been underserved when considering the use of biological control based on microbial agents. For urban and athletic turf grasses, a newly discovered baculovirus offers the opportunity to develop a biological pesticide for control of the black cutworm. Research will focus on basic and applied aspects of production, formulation, and efficacy of this baculovirus for development as a biological insecticide.
Invasive weed species among range grasses such as Medusahead may obtain enhanced fitness as a result of associations with endophytic microbes. Research will utilize classic microbial and newly developed molecular techniques to characterize endophytic microbes of the weedy plants and identify those providing competitive advantages to the weeds. Subsequent research will strive to discover mycoviruses to attach the endophytes of the weedy plant, to convert the competitive advantage back to the desired crop plant.
Progress Report
Substantial progress has been made in the second year of this research project.
For Objective 1, In vivo production of the baculovirus (AgipMNPV) of the black cutworm remains the most attractive method for production and commercialization of this biopesticide. Our laboratory was successful in optimizing variables to increase production of wild-type virus about three fold. Laboratory evaluations demonstrated that newly hatched larvae remain highly susceptible to virus infection for about 5 days. When applied to field grown grass, the virus applications had good residual activity for several days, which (when combined with larval susceptibility) suggest that once weekly applications may provide continued control of this pest in the field.
We have made significant progress in Objective 2, for a second year we have isolated fungal strains from the invasive weed, medusahead (Taeniatherum caput-medusae). The plants were sampled from their invaded range in the western United States and from their native range in Europe. For this year, plants were sampled from Bulgaria and Serbia. We successfully obtained fungal isolates from the roots, seeds, stem and leaves from these plant samples. In addition, DNA samples have been extracted from all of the plant tissues for future analysis of the microbial communities based on high throughput DNA sequencing techniques. These studies will allow us to determine how endophytes impact the success of invasive weeds and may offer potential approaches to limit their invasions.
We have made significant progress in Objective 4. All of the strains isolated from this year’s field work have been accessioned into the database and are available for future research needs. We have preliminary identification on most samples using two separate genes.
Accomplishments
1. Optimized production of baculovirus effective against black cutworm. ARS researchers at Peoria, Illinois, were successful in improving the production yield through optimizing the production conditions of the baculovirus AgipMNPV (a pathogen specifically infects cutworm larvae). This accomplishment is in support of developing the baculovirus AgipMNPV as a biopesticide for control of the black cutworm infesting turf grass grown for golf tees and greens as a replacement for chemical insecticide applications. Defining parameters for economical production of baculoviruses to be used as biological insecticides remains a major factor limiting successful commercialization. Evaluating virus products, for both the number of particles produced and the insecticidal activity of those particles, insures the quality of the active agent for subsequent research for development of this agent as an ecologically benign pest control technology. Successful adoption for highly managed turf grass, will support expanded use of this baculovirus for other crops and vegetables where the cutworm is a pest. In addition, successful development of biological pest controls will prevent plant damage without adverse effects on beneficial insects or non-target animals, contamination of environmental resources such as surface water, or posing a toxicity hazard to pesticide applicators or others in the treated area.
2. Completed fungal endophyte survey of the invasive weed, medusahead. ARS researchers at Peoria, Illinois, were successful in completing the first survey of the fungal endophytes from the invasive weed, medusahead (Taeniatherum caput-medusae). Endophytes are microorganisms that live within plants and are thought to help the plant tolerate different environmental stresses. In this emerging scientific field, it is unclear of the role these endophytes play in helping invasive weeds out compete the native plants. This initial dataset provides the foundation to start understanding these complex interactions and to determine if these interactions can be exploited to control the spread of this weed. In addition, we have identified and described a variety of new bacteria species that are new to science. These novel species were accessioned in to our culture collection to be evaluated in the future for commercial potential. Understanding the relationship between these microbes and the weed will allow us to develop new strategies to selectively target and control the weed for the benefit of ranchers and the natural ecosystems.
Review Publications
Chow, A., Dunlap, C.A., Jackson, M.A., Flores, D., Patt, J.M., Setamou, M. 2016. Oviposition behavior and survival of Tamarixia radiata (Hymenoptera: Eulophidae), an ectoparasitoid of the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae), on hosts exposed to an entomopathogenic fungus. Journal of Economic Entomology. 109:1995-2005. doi: 10.1093/jee/tow164.
Dunlap, C.A., Bowman, M.J., Schisler, D.A., Rooney, A.P. 2016. Genome analysis shows Bacillus axarquiensis is not a later heterotypic synonym of Bacillus mojavensis; Reclassification of Bacillus malacitensis and Brevibacterium halotolerans as heterotypic synonyms of Bacillus axarquiensis. International Journal of Systematic and Evolutionary Microbiology. 66:2438-2443. doi: 10.1099/ijsem.0.001048.
Dunlap, C.A., Saunders, L.P., Schisler, D.A., Leathers, T.D., Naeem, N., Cohan, F.M., Rooney, A.P. 2016. Bacillus nakamurai sp. nov., a black pigment producing strain. International Journal of Systematic and Evolutionary Microbiology. 66(8):2987-2991. doi: 10.1099/ijsem.0.001135.
Ling-Yun, G., Dunlap, C.A., Weiler, L., Rooney, A.P., Guan-Jun, C., Zong-Jun, D. 2016. Wenzhouxiangella sediminis sp. nov. isolated from coastal sediment. International Journal of Systematic and Evolutionary Microbiology. 66:4575-4579. doi: 10.1099/ijsem.0.001393.
Hamm, P.S., Caimi, N.A., Northup, D.E., Valdez, E.W., Buecher, D.C., Dunlap, C.A., Labeda, D.P., Lueschow, S.R., Porras-Alfaro, A. 2017. Western bats as a reservoir of novel Streptomyces species with antifungal activity. Applied and Environmental Microbiology. 83:e03057-03016. doi: 10.1128/AEM.03057-16.
Muturi, E.J., Ramirez, J.L., Rooney, A.P., Dunlap, C.A. 2016. Association between fertilizer-mediated changes in microbial communities and Aedes albopictus growth and survival. Acta Tropica. 164(2016):54-63.
Palazzini, J.M., Dunlap, C.A., Bowman, M.J., Chulze, S.N. 2016. Bacillus velezensis RC 218 as a biocontrol agent to reduce Fusarium head blight and deoxynivalenol accumulation: Genome sequencing and secondary metabolite cluster profiles. Microbiological Research. 192:30-36. https://doi.org/10.1016/j.micres.2016.06.002.
Rooney, A.P., Dunlap, C.A., Weiler, L. 2016. Acinetobacter lactucae sp. nov., isolated from iceberg lettuce (Asteraceae: Lactuca sativa). International Journal of Systematic and Evolutionary Microbiology. 66:3566-3572. doi:10.1099/ijsem.0.001234.
Jin, S., Jun, X., Dunlap, C.A., Rooney, A.P., Zong-Jun, D. 2016. Psychroflexus saliphilus sp. nov., isolated from a marine solar saltern. International Journal of Systematic and Evolutionary Microbiology. 66:5124-5128. doi: 10.1099/ijsem.0.001482.
Xia, J., Dunlap, C.A., Weiler, L., Rooney, A.P., Chen, G., Du, Z. 2016. Longibacter salinarum gen. nov., sp. nov., isolated from a marine solar saltern. International Journal of Systematic and Evolutionary Microbiology. 66:3287-3292. doi:10.1099/ijsem.0.001190.
Labeda, D.P., Dunlap, C.A., Rong, X., Huang, Y., Doroghazi, J.R., Ju, K.-S., Metcalf, W.W. 2016. Phylogenetic relationships in the family Streptomycetaceae using multi-locus sequence analysis. Antonie Van Leeuwenhoek. 110(4):1-21.
Mascarin, G.M., Dunlap, C.A., Barrigossi, J.D., Quintela, E.D., De Noronha, N.C. 2016. First record of epizootics in the ocola skipper, Panoquina sp. (Lepidopera: Hesperiidae), caused by Isaria tenuipes in flooded rice fields of Central Brazil. Journal of Applied Microbiology. 122:1020-1028. doi: 10.1111/jam.13390.
Xu, Z., Zhang, H., Han, J., Dunlap, C.A., Rooney, A.P., Mu, D., Du, Z. 2017. Colwellia agarivorans sp. nov., an agar-digesting marine bacterium isolated from coastal seawater. International Journal of Systematic and Evolutionary Microbiology. 67(6):1969-1974. doi: 10.1099/ijsem.0.001897.
