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Genetic Manipulation of Broad Host-Range Fungi for Biological Control of Weeds

Published online by Cambridge University Press:  12 June 2017

David C. Sands
Affiliation:
Dep. Plant Pathol., Mont. State Univ., Bozeman, MT 59717
Eugene J. Ford
Affiliation:
Dep. Plant Pathol., Mont. State Univ., Bozeman, MT 59717
R. Vincent Miller
Affiliation:
Mycogen Corp., 3303 McDonald Ave., Ruston, LA 71270

Abstract

Few plant pathogens are both lethal and specific enough to be effective weed control agents. In short, highly specific organisms seldom kill. Two genetic approaches to overcome this problem are to delimit the host range of lethal pathogens or to enhance the efficacy of host-specific ones. Narrowing the virulence or survival of a deadly pathogen seems more plausible than imparting new characters to a nonlethal organism. Our approach has been to genetically restrict the host range or to decrease the survival and/or spread of Sclerotinia sclerotiorum (Lib.) de Bary, a highly virulent and aggressive pathogen of several weeds. Working with this fungus, three classes of induced mutants which meet criteria for delimitation were obtained: auxotrophic mutants that only attack plants when applied concomitantly with an exogenous source of the required nutrient; mutants unable to form sclerotia, structures required for long-term survival and precursors to fruiting bodies; and mutants with reduced virulence and/or host ranges. These studies demonstrate the validity of genetically improving bioherbicides and greatly expanding the number of fungi that may be useful as bioherbicides.

Type
Feature
Copyright
Copyright © 1990 Weed Science Society of America 

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References

Literature Cited

1. Adams, P. B. 1974. Host range of Whetzelinia sclerotiorum (Lib.) Korf and Dumont (Sclerotinia sclerotiorum (Lib.) De Bary). Plant Prot. Inst., BARC-West, U.S. Dep. Agric., Beltsville, MD.Google Scholar
2. Anonymous. 1970. Index of plant diseases in the United States. Agric. Handb. No. 165, Crop Res. Div., Agric. Res. Serv., U.S. Dep. Agric., Washington, DC.Google Scholar
3. Broston, B. S., and Sands, D. C. 1986. Field trials of Sclerotinia sclerotio rum to control Canada thistle (Cirsium arvense). Weed Sci. 34:377380.CrossRefGoogle Scholar
4. Charudattan, R. 1985. The use of natural and genetically altered strains of pathogens for control. Pages 347–372 in Hoy, M. A. and Herzog, D. C., eds. Biological Control in Agricultural IPM Systems. Academic Press, New York.Google Scholar
5. Miller, R. V., Ford, E. J., and Sands, D. C. 1989. A Non-sclerotial pathogenic mutant of Sclerotinia sclerotiorum . Can. J. Microbiol. 35:517520.Google Scholar
6. Miller, R. V., Ford, E. J., Zidack, N. K., and Sands, D. C. 1989. A pyrimidine auxotroph of Sclerotinia sclerotiorum for use in biological weed control. J. Gen. Microbiol. 135:20852091.Google Scholar
7. Price, K., and Colhoun, J. 1975. Pathogenicity of isolates of Sclerotinia sclerotiorum (Lib.) De Bary to several hosts. Phytopathol. Z. 83:232238.Google Scholar
8. Purdy, L. H. 1979. Sclerotinia sclerotiorum: History, diseases and symptomology, host range, geographic distribution, and impact. Phytopathology 69:875880.Google Scholar
9. Templeton, G. E., TeBeest, D. O., and Smith, R. J. Jr. 1979. Biological weed control with mycoherbicides. Ann. Rev. Phytopathol. 17:301310.Google Scholar
10. Turner, S. K., Fay, P. K., Sharp, E. L., and Sands, D. C. 1981. Resistance of Canada thistle (Cirsium arvense) ecotypes to a rust pathogen (Puccinia obtegens). Weed Sci. 29:623624.Google Scholar