Progress 08/22/06 to 06/30/09
Outputs
Progress Report Objectives (from AD-416) Optimize multiple treatment factors to enhance biocontrol of Fusarium Head Blight. Approach (from AD-416) Optimize biocontrol of wheat scab incited by Gibberella zea (anamorph, Fusarium graminearum) as follows. Using greenhouse and field plant bioassays, evaluate the effects on biocontrol efficacy of multiplexing applications of superior biocontrol agents of scab of wheat that were discovered in previous cooperative research between ARS and The Ohio State University. Determine the feasibility of combining biocontrol agents with top fungicides, UV protectants, and resistant cultivars to acquire additive or synergistic levels of scab disease control. Improve bioreactor liquid culture media and incubation conditions to increase the quantity, efficacy, and amenability to formulation and shelf-life of biocontrol agent biomass produced. Through the use of molecular and bioassay techniques, determine the molecular basis of enhanced stress tolerance of biocontrol strains improved through production and selection techniques. Significant Activities that Support Special Target Populations Both the Agricultural Research Service (ARS) and The Ohio State University (OSU) are interested in research to develop new pest management technologies that reduce agricultural dependence on chemical pesticides. One source of such new technologies are beneficial microorganisms that have the potential for development into commercial biological control products that reduce plant disease when used alone or in combination with reduced levels of traditional pesticides. Our specific collaborative research interest is biocontrol of Fusarium head blight (FHB) of wheat. No single control measure from among pesticides, biological control, cultural control, disease forecasting and the use of resistant varieties is likely to reduce FHB to economically acceptable levels. Using biological control measures as part of an integrated management strategy against FHB is understudied yet has considerable potential for significantly contributing to the reduction of FHB and deoxynivalenol (DON) in wheat. The utility of Cryptococcus flavescens OH 182.9, a yeast antagonist of FHB that was discovered in our previous collaborative investigations, would be improved if the strain were tolerant of fungicides since this would allow the antagonist to be combined with selected fungicides to reduce the severity of FHB. Because the chemical prothioconazole (PTCT) has been approved for field use against FHB on wheat, the potential of combining this fungicide with a yeast biocontrol agent was studied on several levels. PTCT-tolerant variants of FHB antagonist OH 182.9 were generated and shown to be more effective in reducing symptoms of FHB in greenhouse studies than was the wild-type fungicide-sensitive strain. Results of field trials conducted in Peoria, Illinois, and Wooster, Ohio, generally confirmed this trend. In nearly every instance tested, combinations of the PTCT variants of OH 182.9 and PTCT were more effective in enhancing yield and test weight, and in reducing disease severity, Fusarium damage kernels and DON than was either component tested alone though averages were not separable statistically. The discoveries that several PTCT variants of FHB antagonist OH 182.9 possess enhanced efficacy in reducing FHB and can be successfully combined with a fungicide are key steps in the process of developing successful FHB control strategies that include yeast antagonist OH 182.9. Personal visits between the collaborating individuals at ARS and OSU took place three times: at professional society meetings, when field trials were established and later monitored at the Wooster, OH, field facilities. Numerous phone conversations and email exchanges took place as needed and concentrated on the discussion of research plans, progress, and results. Formal and informal reports were also exchanged as appropriate.
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Progress 10/01/06 to 09/30/07
Outputs
Progress Report Objectives (from AD-416) Optimize multiple treatment factors to enhance biocontrol of Fusarium Head Blight. Approach (from AD-416) Optimize biocontrol of wheat scab incited by Gibberella zea (anamorph, Fusarium graminearum) as follows. Using greenhouse and field plant bioassays, evaluate the effects on biocontrol efficacy of multiplexing applications of superior biocontrol agents of scab of wheat that were discovered in previous cooperative research between ARS and The Ohio State University. Determine the feasibility of combining biocontrol agents with top fungicides, UV protectants, and resistant cultivars to acquire additive or synergistic levels of scab disease control. Improve bioreactor liquid culture media and incubation conditions to increase the quantity, efficacy, and amenability to formulation and shelf-life of biocontrol agent biomass produced. Through the use of molecular and bioassay techniques, determine the molecular basis of enhanced stress tolerance of biocontrol strains improved through production and selection techniques. Significant Activities that Support Special Target Populations This report documents accomplishments conducted under a Specific Cooperative Agreement(SCA) between Agricultural Research Services (ARS) and Ohio State University (OSU). Additional details of research can be found in the parent project 3620-22410-011-00D, "Discovery and Application of Microbial Production and Formulation Biotechnologies to Enhance Biocontrol of Fungal Plant Diseases.� Because it is a research priority of both OSU and ARS to develop new pest management technologies that reduce our dependence on chemical pesticides, we are studying the possibility of utilizing microorganisms naturally present in agricultural ecosystems as environmentally compatible alternatives for controlling disease or as supplements to reduce levels of traditional chemicals. Our specific collaborative research interest is biocontrol of Fusarium head blight (FHB). It has become apparent over the course of considerable research effort by private, governmental and university research laboratories in this country and around the world that no one control measure from among pesticides, biological control, cultural control, disease forecasting and the use of resistant varieties is likely to single-handedly consistently reduce FHB to economically acceptable levels. Our research during this last year concentrated on conducting a field comparison of the FHB fungicide Folicur 3.6 F, a commercial biocontrol agent of fungal disease and Cryptococcus flavescens OH 182.9, an ARS/OSU-discovered antagonist with confirmed activity against FHB, on a susceptible and moderately resistant OSU-developed wheat variety (Freedom) when the materials were applied at two different dosages. Initial field trial results indicated that OH 182.9 and Folicur 3.6 F applied at flowering had the most favorable trend in reducing disease though there was no statistical significance in comparison to the untreated check. Application of treatments to heads that were still in boot generally resulted in disease severities that were very close to those of the untreated check. In an additional collaborative study conducted under this SCA, work has begun to isolate and characterize a naturally occurring fungicide-tolerant variant of C. flavescens. Fungicide tolerance is being sought against prothioconazole because recent evidence indicates that the fungicide may reduce both FHB and the accumulation of the fungicide deoxynivalenol in harvested grain. Monitoring activities took place within this project in the form of telephone calls and emails on at least a monthly basis. Personal visits with the collaborator took place three times in the last year when field trials were established and later monitored at the Wooster, OH, field facilities of the collaborator. A personal visit with the collaborator also took place and at the National Meeting of the American Phytopathological Society. In all types of communication, research plans, progress, and results were discussed and formal and informal reports exchanged as appropriate.
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