Linear Plasmids in the Phytopathogenic Fungus Claviceps Purpurea
The ascomycete Claviceps purpurea is a common parasite of cereals and nonagricultural grasses. The life cycle of this fungus involves two morphologically and physiologically different mycelial forms. After infection of young ovaries (by ascospores or conidia), initially the so-called sphac-elial mycelium is formed, which produces masses of conidia. This mycelial form may be propagated in axenic culture without special requirements. In a later stage of infection the mycelium becomes dense and forms the well-known sclerotial stage. Since medieval times these sclerotia were used as drugs; they contain the so-called ergot alkaloids which still have much pharmaceutical importance (for review, see Ref. 2). Because of this bio-technological relevance, C. purpurea has become one of the best investigated fungi, but mainly with respect to the physiology of alkaloid synthesis (see Ref. 14); otherwise, only a few genetic data have been published for C . purpurea. This may be due to its long life cycle, which may be performed only partially in the laboratory: sclerotia are only formed on the host, never in axenic culture. Sclerotia are the starting point for the sexual cycle; they germinate to form perithecia-containing stroma heads. The needle-like ascospores are homokaryotic. Claviceps has been shown to be monoecious or homothallic (3), a characteristic which does not facilitate genetic analysis.
KeywordsWild Strain PHYTOPATHOGENIC Fungus Ergot Alkaloid Axenic Culture Rhizoctonia Solani
Unable to display preview. Download preview PDF.
- 2.Esser, K., and A. Düvell (1984) Biotechnological exploitation of the ergot fungus Claviceps purpurea. Process Blochem. 19:143–149.Google Scholar
- 8.Honeyman, A.L., and T.C. Currier (1983) The isolation and characterization of two linear DNA elements from Gaeumannomyces graminis var. tritici, the causative agent of “Take-All-Disease” of wheat. Eighty-third Annual Meeting of the American Society for Microbiology, New Orleans (abstract).Google Scholar
- 9.Kistler, H.C., and S. Leong (1986) Linear plasmid-like DNAs in the plant pathogenic fungus Fusarium oxysporum f. sp. conglutinans. J. Bacteriol. (in press).Google Scholar
- 14.Rehacek, Z. (1984) Biotechnology of ergot alkaloids. Trends in Biotechn. 2:167–172.Google Scholar
- 15.Tudzynski, P., and A. Düvell (1985) Molecular aspects of mtDNA and mt plasmids in Claviceps purpurea. In Achievements and Perspectives of Mitochondrial Research. Vol. II. Biogenesis, E. Quagliariello, E.C Slater, F. Palmieri, C. Saccone, and A.M. Kroon, eds. Elsevier, Amsterdam, New York, pp. 249–256.Google Scholar
- 19.Tudzynski, P., P. Rogmann, and H.H. Geiger (1986) Molecular analysis of mtDNA from rye (Secale cereale L.). Theor. Appl. Genet, (in press).Google Scholar