Brief Summary of Minutes of Annual Meeting

Minutes of the 2000 meeting were approved, with an ensuing discussion concerning minutes, annual reports and committee project proposal. In an effort to better coordinate transfer of information (especially for new representatives), the committee agreed that all members should receive electronic copies of meeting minutes, annual reports and the current project description.

Comments from the Administrative Advisor: Dr. Steve Pueppke discussed that the midterm review for NC-125 will take place this year. The requirements for the formal evaluation can be found at www.wisc.edu/ncra, and will involve a written report with directors. The evaluation will likely take place during the spring of 2002.

The future of agricultural funding sources was discussed. Intellectual properties are becoming of greater importance in agriculture. Establishing the mechanisms for the preservation of intellectual property is a big concern, since it is in conflict with the concept of land grant institutions. The need for new policies and common policies for all institutions is necessary.

Announcements were made stating that Dr. McSpadden Gardener is the new Ohio State University representative and Dr. Ann Macguidwin is the new Wisconsin representative.

The committee took a tour of the USDA facilities associated with biocontrol research. The tour was followed by presentations of biocontrol researchers at USDA. Dr. Pat Slininger presented research on biocontrol of potato dry rot and sprouting. Dr. David Schisler presented research on biocontrol of Fusarium head blight of wheat, Dr. Mark Jackson presented research on producing and stabilizing fungal biopesticides, and Dr. Robert Behle presented research on improving residual activity of biological pesticides.

The committee meeting continued with state reports. Dr. G. Yuen (Nebraska), reported on the status of biocontrol of turfgrass diseases with Lysobacter sp. strain C3. Dr. D. Kobayashi (New Jersey) updated the progress of the molecular characterization of biocontrol traits in Lysobacter sp. strain C3. Dr. A. Macguidwin, (Wisconsin) discussed refining crop loss models for potato early dying for growers in a potato eco-label program. Dr. B. McSpadden Gardener (Ohio) presented information on studying the microbial ecology of agricultural soils as it pertains to biocontrol. Dr. D. Eastburn (Illinois) reported on the characterization of mycoviruses of Fusarium solani f. sp. glycines. Dr. R. Proctor and Dr. A. Desjardins (Illinois) reported on biocontrol of Fusarium verticilliodes using strains that do not produce the mycotoxin, fumonisin. Dr. C. Martinson (Iowa) reported on white mold control with Sporidesmin. Dr. C. Windels (Minnesota) described the use of green cover crop and soil solarization for suppression of Aphanomyces cochlioides. Dr. B. Nelson (North Dakota) reported on biocontrol of Rhizoctonia solani and degradation of sclerotia of Sclerotinia. Dr. K Garrett (Kansas) discussed the use of models to manage wheat planting for escape from take-all. Dr. G. Safir (Michigan) updated progress on expanding simulation models at the regional scale for monitoring disease.

The committee thanked Dr. Desjardins for her service and hosting the 2001 meeting. Dr. B. Nelson suggested that a letter of appreciation for use of the facilities and acknowledging the time and effort of researchers at the facility should be drafted by the new secretary or chair, and sent to the director of USDA-ARS-NCAUR.

Dr. Don Kobayashi, Rutgers University, secretary, will automatically advance to chair. Dr. Brian McSpadden Gardener was elected as the new secretary. The next meeting site was selected as New Brunswick, NJ. The tentative date was agreed upon as some time in Oct/Nov.
Meeting was adjourned at 12:00 pm, November 9, 2001.

PROGRESS OF THE WORK AND PRINCIPAL ACCOMPLISHMENTS:

OBJECTIVE I. Develop systems for effective utilization of microbial amendments for biocontrol of soilborne plant pathogens in the North Central agroecosystem.


A wide range of research on this objective by members of the NC-125 Committee was continued in 2001. The abundance and diversity of indigenous biocontrol Pseudomonas species that produce antifungal metabolites were examined in the rhizosphere of tomato and cabbage plants grown in OH. Manure amendments increased the number of pseudomonads of all types, but compost also enriched for producers of the antifungal metabolite pyoluteorin. Host genotypes and growth conditions (greenhouse vs. field) impacted the structure of rhizosphere microbial populations in OH. Disease control of Sclerotinia sclerotiorum on soybean in IA was prolonged for up to five years after soil incorporation of the sclerotial parasite Sporidesmium sclerotivorum. Experiments were continued to optimize inoculum production for S. sclerotivorum, with alginate pellets in SM-4 medium providing the fastest production of spores. In NE, Lysobacter sp. C3, formerly reported as a strain of Stenotrophomonas maltophilia, was shown effective in controlling a broader range of diseases, including wheat head blight, wheat stem rust, and anthracnose in turfgrass. The survival of Lysobacter C3 in turfgrass canopies following exposure to solar ultraviolet was related to canopy density and canopy height. The efficacy of fumonisin gene knock-out mutants in reducing fumonisin production in maize by Fusarium verticillioides was demonstrated in field tests in IL and IA. Thus, fumonisin-nonproducing strains have potential as biological control agents for reducing fumonisins in maize.

In KS, a model was developed to determine how different seeding patterns of wheat might affect yield loss to Gaeumannomyces graminis var. tritici when wheat was direct-drilled into fields where wheat was infected with take-all in the previous season. Planting parallel to and in between the previous year=s rows resulted in a much lower predicted loss in yield than angled planting, provided there was not an important offset in the position of the parallel planting. In MI, a model is being developed for assessment of agroecosystems and biological control potential for the North Central Region. A Modeling Application System Integrative Framework has been developed to accommodate large amounts of spatial-temporal outputs from regional scale simulation experiments. In WI, crop loss models for potato early dying are being refined for growers in a potato eco-label program.

Objective II. Develop systems to manage the indigenous microflora to suppress diseases caused by soilborne plant pathogens.

To better characterize the structure of microbial communities, a high-throughput T-RFLP-based assay of ribosomal DNA sequences (FT-ARDRA) was developed in OH. Significant differences were observed in the bacterial communities colonizing corn and soybean plants grown in the same soil. Abundance and diversity of 2,4-diacetylphloroglucinol (DAPG)-producing biocontrol pseudomonads inhabiting Ohio soils was investigated. Rhizospheres of corn and soybean plants harbored sufficient populations of these biocontrol bacteria to suppress root diseases. RFLP analysis and partial sequencing of selected genes was used to identify different genotypes of DAPG-producing pseudomonands that might differ in adaptability to diverse soil environments and other traits that might affect biocontrol efficacy. In NE, systemic resistance against Bipolaris sorokiniana was induced by application of Lysobacter sp. C3 to roots of tall fescue, but only localized resistance was elicited by application to leaves. Glucanase-deficient mutants of Lysobacter sp. C3 were able to suppress leaf spot in tall fescue and damping-off in sugarbeet, indicating that glucanase activity was not required for biocontrol. Rigorous genetic analysis, and nutritional and biochemical tests in NJ clarified the taxonomy of Lysobacter sp. C3. This biocontrol strain is closely related to another biocontrol agent, strain N4-7, and to bacteria from hydrothermal vents. Chitinases of strain C3 were cloned and characterized, and a type III secretion pathway was identified by homology with genes from Xanthomonas.


To study biology of binucleate Rhizoctonia in ND, strains with the carboxin resistance gene were obtained by transformation. The resulting transformants, however, were less efficient biocontrol agents than the wild-type strain, due in part to inefficient colonization and penetration of plant surfaces. Experiments demonstrated that resistance induced in soybean by binucleate Rhizoctonia is localized but is not systemic. Preliminary experiments identified Bacillus spp. isolated from sclerotia of S. sclerotiorum as potential degraders of sclerotia. Survival of oospores of Aphanomyces cochlioides in the soil on sugar beet hypocotyl pieces is being investigated in MN under different field conditions with cover crop residues and soil solarization treatments. Techniques for identification of viable, dead and decomposing oospores have been developed. An ascospore-nonproducing mutant of Gibberella zeae was obtained by deleting the mating locus and was applied to maize stalk pieces to produce an inoculum for field tests. A field test of the mutant strain in IL indicated that ascospore production on maize stalk residues can play a major role in wheat head blight epidemics. The relationship of mycoviruses to virulence of Fusarium solani f. sp. glycines, causal agent of sudden death syndrome of soybeans, is being investigated in IL. Pathogencitiy tests in the greenhouse indicated some significant differences in disease severity between isolate groups with different mycovirus banding patterns. These experiments are being repeated and continued with isolates that have been cured of mycovirus infection by treatment with heat or cycloheximide.

USEFULNESS OF FINDINGS:

Research in this project has expanded our knowledge of which organisms offer potential as biocontrol agents for commercial development. Basic biological studies continue to give us new insights into how biocontrol works and how it can be utilized to benefit agriculture. New tools are being developed to aid in the understanding of biocontrol and its applications. New factors affecting biocontrol continue to be discovered for pathogen-crop systems. An important contribution of the research is an increase in understanding the limitations of biocontrol and the types of agricultural systems where biocontrol has the most utility.

STATEMENT OF ACCOMPLISHMENTS:

Significant accomplishments have resulted from this project. Potential biocontrol microorganisms have been identified and tested on various crops and under different agricultural systems. Known biocontrol microbes have been tested on new crops and information on their activities expanded. Factors affecting biocontrol activities were identified and interactions of biocontrol-pathogen-host were studied. Diseases not previously tested for control by biocontrol microbes were studied. The mechanisms of biocontrol were elucidated for certain biocontrol agents, giving us new directions on approaching the problem. New tools for the study and understanding of biocontrol were developed. New strategies for using biocontrol agents were developed and limitations on biocontrol of certain pathogens were discovered.

WORK PLANNED FOR NEXT YEAR:

The NC-125 project objectives are similar to the past project. Research will continue on many of the same crop systems, but new members will be contributing information on different diseases, new biocontrol organisms and new approaches to biocontrol.

McGuire, M. R., R. W. Behle, H. N. Goebel, and T. C. Fry. 2000. Calibration of a sunlight simulator for determining solar stability of Bacillus thuringiensis and Anagrapha falcifera nuclear polyhedrovirus. Environ. Entomol. 29:1070-1074.

Tamez-Guerra, P., M. R. McGuire, R. W. Behle, J. J. Hamm, R. H. Sumner, and B. S. Shasha. 2000. Sunlight persistence and rainfastness of spray-dried formulations of baculovirus isolated from (Lepidoptera: Noctuidae). J. Econ. Entomol. 93:210-218.

Kilic, O., and Yuen, G. Y. 2001. Induced resistance by Stenotrophomonas maltophilia strain C3 suppresses conidial germination and leaf spot development by Bipolaris sorokiniana. Phytopathology 91:S48.

Yuen, G.Y., Jochum, C.C., Giesler, L.J., Shulski, M.D., Walter-Shea, E.A., Hubbard, K.G., and Horst, G.L. 2001. UV-B Biodosimetry in Turfgrass Canopies. Crop Science 41: in press.

Yuen, G.Y., and Kilic, O. 2001. Evidence of induced resistance in the control of Bipolaris sorokiniana in tall fescue by Stenotrophomonas maltophilia C3. Int. Turfgrass Soc. Res. J. 9:736-741.

Yuen, G.Y., and Zhang, Z. 2001. Control of brown patch using the bacterium Stenotrophomonas maltophilia C3 and culture fluid. Int. Turfgrass Soc. Res. J. 9:742-747.

Yuen, G.Y., Steadman, J.R., Lindgren, D.T., Schaff, D., and Jochum, C. 2001. Bean rust biological control using bacterial agents. Crop Protection 20:395-402.

Zhang, Z., Yuen, G.Y., Sarath, G., and Penheiter, A. 2001. Chitinases from the plant disease biocontrol agent, Stenotrophomonas maltophilia C3. Phytopathology 91:204-211.

Kobayashi, D.Y., Reedy, R.M., Bick, J.A., and Oudemans, P.V. Characterization of a chitinase gene from Stenotrophomonas maltophilia and its involvement in biological control. Appl. Environ. Microbiol.: accepted with revisions (9/01).

Bick, J.A., Reedy, R.M., and Kobayashi, D.Y. 2001. Genetic analysis of chitinolytic activity from the biocontrol agent Stenotrophomonas maltophilia strain C3. Phytopathology 91:S8-9.

Reedy, R.M., and Kobayashi, D.Y. 2001. Evidence for a type III secretory pathway in the biocontrol bacterium Stenotrophomonas maltophilia strain C3. Phytopathology 91:S75.

McSpadden Gardener, B., and Weller, D.M. 2001. Changes in populations of rhizosphere bacteria associated with take-all disease of wheat. Appl. Environ. Microbiol. 67: 4414-4425.

McSpadden Gardener, B., et al. 2001. A rapid polymerase chain reaction-based assay characterizing rhizosphere populations of 2,4-diacetylphloroglucinol-producing bacteria. Phytopathology 91:44-54.

Marvelli, R. A., Eastburn D. M., and Domier, L. 2001. Detection of mycoviruses in Fusarium solani f. sp. glycenes. Phytopathology 91:S58.

Dyer, A.T., and Windels, C.E. 2001. Visual viability assay for oospores of Aphanomyces cochlioides. Phytopathology 91:S25.

Dyer, A.T., and Windels, C.E. 2001. Methods for assessing viability of Aphanomyces cochlioides oospores. J. Sugar Beet Res. 38:65.

Dyer, A.T., and Windels, C.E. 2001. Methods for assessing viability and maturation of Aphanomyces cochlioides oospores. 2000 Minnesota-North Dakota Sugarbeet Res. Ext. Rept. 31:243-253.

Nelson, B D., Christianson, T., and McClean, P. 2001. Effects of bacteria on sclerotia of Sclerotinia sclerotiorum. Proceedings of the IV International Sclerotinia Conference. Central Science Laboratory. York, England. July 2001. Pages 39-41.

Nelson, B. D. 2001. Adaptation and importance of Sclerotinia sclerotiorum in North Dakota. Proceedings of the IV International Sclerotinia Conference. Central Science Laboratory. York, England. July 2001. Pages 177-178.

Nelson, B., and Christianson, T. 2001. Biology of Binucleate Rhizoctonia. P. 48-49. In Proceedings Biocontrol in a New Millennium: Building for the Future on Past Experience. D. M. Huber, editor. Estes Park, CO. October 26-29, 2000.

Nelson, B., Helms, T., Christianson, T., Martin, G., Harrington, G., and Mars, G. 2000. Evaluation of soybean cultivars for resistance to Sclerotinia stem rot, 1999. Biol. Cult. Test Cont. Plant Dis. 16:80.

Mars, G. A., Nelson, B. D., and Helms, T. C. 2001. Effect of Sclerotinia stem rot on seed yield of two soybean cultivars inoculated at two growth stages. Phytopathology 91:

Nelson, B. and Lamey, A. 2000. Sclerotinia diseases of sunflower. Cooperative Extension Service Circular PP-840. March 2000. North Dakota State University. 8 pp.