Temperature sensitive mutants (ts-mutants) are godd material for studying cell division and differentiation. Two hundred and seventy-four ts-mutants of Magnaporthe grisea were induced by UV radiation. These mutants could grow at 25℃, but not at 33℃. Pathogenicity test indicated that the pathogenicity of 32 ts-mutants reduced distinctly. Under 33℃ conditions, seven of them did not germinate, 12 stopped growing after germination and no appressorium formed, nine stopped growing after appressorium formed, for mutants formed swell and bunch appressorium, then stopped growing. The ability of perithecia formation of some mutants was changed.

Selecting by indirect ELISA eleven hybridoma cell lines, secreting monoclonal antibodies (McAbs) against Magnaporthe grisea were produced by fusing mouse myeloma cells (SP2/0) with spleen cells from BALB/c mice immunized with the mixture of conidia、germ tubes and appressoria of M. grisea using 50% PEG. The result of IFTC test showed that four McAbs, named as 2B4、4A1、1D1、and 2H4 specificlly bound to the cell wall surface of the fungus; Western blotting revealed that 2B4、4A1、1D1 were recognized different protein antigens from the surface of conidia and germ tubes; These four McAbs could effectively interfere with the appressorium formation both on cellophane membrance and the surface of onion epidermis and inhibit the disease leaf lesions development in vitro test.

[1] OU S H. Rice disease. 2nd ed.[M]. Surrey: Commonwealth Mycology Institute, 1985. [2] ROSSMAN A Y, HOWARD R J, VALENT B. Pyricularia grisea, the correct name for the rice blast disease fungus[J]. Mycologia, 1990, 84: 509-512. [3] HAMER J E, HOWARD R J, CHUMLEY F G, et al. A mechanism for surface attachment in spores of plant pathogenic fungus[J]. Science, 1988, 239: 288-290. [4] HOWARD R J. Cell biology of pathogenesis[A]. ZEIGLER R S, LEONG S A, TENG P S. Rice Blast Disease[M]. Wallingford, UK: CAB International, 1995. 3-22. [5] TALBOT N J. Having a blast: exploring the pathogenicity of Magnaporthe grisea[J]. Trends in Microbiology, 1995, 3: 9-16. [6] WEINTRAUB R T, MILLER W E, SCHANTZ E J. Chemical stimulation of germination of spores of Piricularia oryzae[J]. Phytopathology, 1958, 48: 7-10. [7] BOURETT T M, PICOLLELLI M A, HOWARD R J. Postembedment labeling of intracellular concanavalin A-binding sites in freeze-substituted fungal cells[J]. Experimental Mycology, 1993, 17: 223-235. [8] 林福呈，李德葆. 植物病原真菌附着胞形成及其基因表达调节[J]. 植物病理学报，1997, 27 (3): 193-197 [9] BOURETT T M. HOWARD R J. Ultrastructural immunolocation of actin in a plant pathogenic fungus[J]. Protoplasma, 1991. 163: 199-202. [10] DE JONG J C, McCORMACK B J, SMIRNOFF N, et al. Glycerol generates turgor in rice blast[J]. Nature, 1997, 389: 244-245. [11] MONEY N P. Osmotic pressure of aqueous polyethylene glycols[J]. Plant Physiology, 1989, 91: 766-769. [12] BOURETT T M, HOWARD R J. Actin in penetration pegs of the fungal rice blast pathogen, Magnaporthe grisea[J]. Protoplasma, 1992, 168: 20-26. [13] HOWARD R J, FERRARI M A. Role of melanin in appressorium function[J]. Experimental Mycology, 1989, 13: 403-418. [14] MONEY N P. Measurement of pore size in the hyphal cell wall of Achlya bisexualis[J]. Experimental Mycology, 1990, 14: 234-242. [15] KUBO Y, FURUSAWA I. Melanin biosynthesis. Prerequisite for successful invasion of the fungal plant host by appressoria of Colletotrichum and Pricularia[A]. COLE G T, HOCH H C. THE Fungal Spore and Disease Initiation in Plants and Animals[M] New York, USA: Plenum Press, 1991. 205-218. [16] HOWARD R J, FERRARI M A, ROACH D H, et al. Penetration of hard substrates by a fungus employing enormous turgor pressures[J]. Proc. Natl. Acad. Sci. USA, 1991, 88: 11281-11284. [17] KOLAITUKUDY P E. Enzymatic penetration of the plant cuticle by fungal pathogens[J]. Ann. Rev. Phytopathol., 1985, 23: 223-250. [18] SWEIGARD J A, CHUMLEY F G, VALENT B. Disruption of a Magnaporthe grisea cutinase gene[J]. Molecular and General Genetics, 1992, 232: 183-190. [19] BECHINGER C, GIEBEL K F, SCHNEL M. Optical measurements of invasive forces exerted by appressoria of a plant pathogenic fungus[J]. Science, 1999, 286: 1896-1899