Abstract
This article is concerned with the developmental processes that prime the appressorium of Magnaporthe grisea for mechanical penetration of the host surface. Experiments have shown that melanized appressoria generate enormous turgor pressure following the accumulation of high concentrations of cytoplasmic osmolytes, and thereby deliver substantial invasive force at the tip of a slender penetration hypha. Recent molecular genetic studies provide authoritative evidence for the central role played by melanin biosynthesis in the operation of the appressorium, and still other studies have revealed the identity of some of the osmolytes responsible for turgor generation. However, our picture of appressorial function remains limited by a number of problems: the maximum level of appressorial pressure is still questionable, the metabolic source of the cytoplasmic osmolytes is a mystery, and the processes that control melanization of the appressorial wall are poorly understood. Progress toward the resolution of these issues is discussed.
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References
Talbot, N. J. (1995) Having a blast: Exploring the pathogenicity of Magnaporthe grisea, Trends Microbiol. 3, 9 - 16.
Howard, R. J., and Valent, B. (1996) Breaking and entering: host penetration by the fungal rice blast pathogen, Magnaporthe grisea, Annu. Rev. Microbiol. 50, 491 - 512.
Dean, R. J. (1997) Signal pathways and appressorium morphogenesis, Annu. Rev. Phytopathol. 35, 211234.
Howard, R. J. (1997) Breaching the outer barriers - cuticle and cell wall penetration, in G. Carroll and P. Tudzynski (eds.), The Mycota, Vol 5, Part A, Plant Relationships, Springer-Verlag, Berlin Heidelberg New York, pp. 43 - 60.
Ebata, Y., Yamamoto, H., and Uchiyama, T. (1998) Chemical composition of the glue from appressoria of Magnaporthe grisea, Biosci. Biotechnol. Biochem. 62, 672 - 674.
Money, N. P. (1998) Mechanics of invasive fungal growth and the significance of turgor in plant infection, in K. Kohmoto and O. C. Yoder (eds.), Molecular Genetics of Host-Specific Toxins in Plant Disease, Kluwer Academic Publishers, Dordrecht, The Netherlands, pp. 261 - 271.
Howard, R. J., Ferrari, M. A., Roach, D. H., and Money, N. P. (1991) Penetration of hard substrates by a fungus employing enormous turgor pressures, Proc. Natl. Acad. Sci. U.S.A. 88, 11281 - 11284.
Money, N. P., Caesar-Tonthat, T., Frederick, B., and Henson, J. M. (1998) Melanin synthesis is associated with changes in hyphopodial permeability, wall rigidity, and turgor pressure in Gaeunwnnomyces graminis var. graminis, Fungal Genet. Biol. 24, 240 - 251.
Balhadere, P. V., Foster, A. J., and Talbot, N. J. (1998) Identification of pathogenicity mutants of the rice blast fungus Magnaporthe grisea by insertional mutagenesis, Molec. Plant Microbe Interact.,in press.
Money, N. P., and Howard, R. J. (1996) Confirmation of a link between fungal pigmentation, turgor pressure, and pathogenicity using a new method of turgor measurement, Fungal Genet. Biol. 20, 217227.
De Jong, J. C., McCormack, B. J., Smirnoff, N., and Talbot, N. J. (1997) Glycerol generates turgor in rice blast, Nature 389, 244 - 245.
Bourett, T. M., and Howard, R. J. (1990) In vitro development of penetration structures in the rice blast fungus Magnaporthe grisea, Can. J. Bot. 68, 329 - 342.
Meyer, K. H. (1943) The chemistry of glycogen, Adv. Enzymol. 3, 109 - 135.
Woloshuk, C. P., Sisler, H. D., and Vigil, E. L. (1983) Action of the antipenetrant, tricylclazole, on appressoria of Pyricularia oryzae, Physiol. Plant Pathol. 22, 245 - 259.
Kawamura, C., Moriwaki, J., Kimura, N., Fujita, Y., Fugi, S-i., Hirano, T., Koizumi, S., and Tsuge, T. (1997) The melanin biosynthesis genes of Alternaria alternata can restore pathogenicity of the melanin-deficient mutants of Magnaporthe grisea, Mol. Plant-Microbe Interact. 10, 446 - 453.
Takano, Y., Kubo, Y., Kawamura, C., Tsuge, T., and Furusawa, I. (1997) The Alternaria alternata melanin biosynthesis gene restores appressorial melanization and penetration of cellulose membranes in the melanin-deficient albino mutant of Colletotrichum lagenarium, Fungal Genet. Biol. 21, 131 - 140.
Money, N. P. (1997) Mechanism linking cellular pigmentation and pathogenicity in rice blast disease: A commentary, Fungal Genet. Biol. 22, 151 - 152.
Hester, R. E., and Girling, R. B. (1991) Spectroscopy of Biological Molecules, The Royal Society of Chemistry, Cambridge, U.K.
Greve, J., and Puppels, G. J. (1993) Raman microspectroscopy of single whole cells, in R. J. H. Clark and R. E. Hester (eds.), Biomolecular Spectroscopy, Part A, Vol 20, Wiley and Sons, New York, pp. 231 - 265.
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Davis, D.J., Burlak, C., Money, N.P. (2000). Biochemical and Biomechanical Aspects of Appressorial Development in Magnaporthe Grisea . In: Tharreau, D., Lebrun, M.H., Talbot, N.J., Notteghem, J.L. (eds) Advances in Rice Blast Research. Developments in Plant Pathology, vol 15. Springer, Dordrecht. https://doi.org/10.1007/978-94-015-9430-1_30
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DOI: https://doi.org/10.1007/978-94-015-9430-1_30
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