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.

A mature appressorium cDNA library of rice blast fungus, Magnaporthe grisea, was constructed in a λ TriplEx2 vector by SMARTTM cDNA library containing 2.37×10.6 independent clones about 100% of which harbor foreign cDNA inserts with average size of 660bp. Of 9 randomly selected clones, 2 expressed tags (ESTs) sequences did not have homologous EST sequences of M. grisea in GenBank. The appressorium cDNA library is suitable for gene expression analysis and function analysis of the late stages of appressorium formation and the carly stages of penctration of M. grisea.

We have constructed a fungal subtractive suppressive library enriched in genes expressed during appressorium maturation in Magnaporthe grisea. Sequencing of 250 clones from the subtracted appressorium cDNA library revealed 142 unique genes, represented by 155 non-redundant ESTs (expressed sequence tags). Of these ESTs, 72 have not been previously isolated in M. grisea. RTPCR analysis of 105 of the genes discovered found transcripts corresponding to 71 of the ESTs only in mature appressoria while transcripts corresponding to a further 34 of the isolated ESTs were expressed both in appressoria and condia/mycelia. Genes specifically expressed in appressorium identified by SSH included a number that have been previously implicated in appressorium formation or function including GAS1, GAS3, and PTH11.

Nine hundred and seventy-six bacterial isolates were obtained in this study, among which a bacterial antagonistic isolate, Bacillus subtilis S9 from sugarcane rhizosphere showed cell-lytic effect on the plant pathogens, Rhizoctonia solani, Pythium ultimum and Fusarium oxysporum f. sp. niveum after 4-day-confronting incubation on PDA plates. However, S9 could not cause obvious inhibitory zones on PDA plates during this incubation. Lytic spots of hyphae of R. solani caused by S9 were clearly presented under scanning electronic microscope. The cell-lytic process of S9 is as follows: Bacterial cells of S9 absorb on hypae of R. solani firstly, and grow and reproduce as the fungal hyphae grow, and then secrete some cell-lytic substances to decompose the hyphae. However, this study revealed that S9 hardly interfered with the growth of the fungal antagonists, such as Trichoderma viride, Chaetomium cupreum and Chaetomium globosum. Pot experiments proved that S9 could effectively control root disease of tomato caused by R. solani. It Suggested that S9 mixed with above fungal antagonists could potentially synergistically control plant diseases caused by pathogenic fungi.