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.

Eleven high effective monoclonal antibodies to Magnaporthe grisea were screened out from 230 hybrid cell strains showing positive reaction in ELISA tests, among which monoclonal antibody 2B4 showed more highly banding to cell wall surfaces of conidia, germ tubes, appressoria, germ tubes, appressoria or/and second infective hypha by indirect-immunofluorcscence test. Ultrastructural analysis and the antigen localisition of monocloual antibody 2B4 with immuno-gold labeling found this antigen protein exists extensively on cell wails of the diftbrrent life stages above, and is a secretion protein. 6 positive cDNAs, MP1, MP2, MP3, MP4, MP5 and MP6 were screened out with 2B4 from conidium cDNA expression library. A 31kDa protein expressed from a positive clone MP1 in a prokaryotic in vitro translation system was consistent with a 15kda protein from the extractive of the fungal surfaces, and its gene cloning and functional analysis are undertaking.

Conidium germination and approssorium formation rate under eight subatratea, different agar surface with various cAMP and IBMX concentration gradients, different nutrient resource, pH value of conidial suspensison, and cultural filter of antigonistic bacteria were observed. Conidium density of its suspeusion and its pH value did not affect the appressorium formation of Magnaporthe grisea 91-11B1, high density (conidia>10 5/mL) and unsuitable pH value (>10 or <4) would significantly reduce the germination of conidia The hydrophobic substratum surfaces could enhance the appressorium formation, The starvation of nutrition and the surfaces of onion epidermis could stimulate the appressorium morphogenesis, and rich mltrition could inhlbh it, Compared with ion-free pure water,tap water could facilitate the appressorium formation, 2.5mmol/L cAMP and 8.0mmol/L IBMX, the mostly commonly used phosphodiesterase inhibitor, significantly promote apressorium formation. Conidia which collected by vibrating method were more elfective to differentiate into appressorium than those by washing method. Among 13 strains of antagonistic bacteria, three sttains, such as Xb216, Xh240 and Xh220 strongly iuhibited the germination and appressorium formation.

Chactomium spp. Are saprophytic Ascomycetes which act as plant debris cellulose destroying fungi with more than 300 species described all over world. These fungi are capable of producing many kinds of antagonistic substances and enzymes, especially cellulases, to suppress many plant pathogens and decay plant straw and municipal refuse, which leave us many aspects to be developed and applied.