| In this study, the disease-resistant geneβ-1,3-glucanase was transferred into apple cultivar Gala and Fuji via Agrobacterium tumefaciens strain EHA 105. The adventitious bud regeneration system and genetic transformation system had been modified by studying the effect of explant types and status on the efficiency of regeneration and transformation. Transgenic plants were obtained and examined by PCR, PCR-Sourthern and RT-PCR. After inoculated Apple Ring Spot,the vigor ofβ-1,3-Glucanase, PAL and PPO in transformed plants were higher than untransformed plants, which proved that the transgenic plants were more disease-resistant. The result showed:1. Adding 10.0～15.0mg/L SNP into culture medium could improve the regeneration rate significantly.2. Some agrobacterium strains were plasmid instability when cultivated the second time under condition of liquid culture without presenting of antibiotic during genetic transformation via agrobacterium-mediated system, the losing increased along with the culture timing. No correlation was found between the losing and one single factor of target genes, promoters, and agrobacterium strains, but there was a correlation between the losing and combination of target genes, promoters, and agrobacterium strains. The losing was mainly related to the concentration of plasmids but liquid culture timing during the culture of 0.5 h~6.0 h. No difference was found in terms of the plasmid losing when liquid culture was done by taken solution directly from previous culture or centrifugate, and no matter bacteria culture or MS3. By comparing the factors on agrobacterium-mediated gene transformation, it suggests the optimal protocol for gene transformation in apple would be: at first, the explants should be pre-cultured for one day or two on the inducing medium with 60～90mg/L saccharose; the bacterium concentration for inoculation should be cultivated twice in the medium without presenting of antibiotic, the appropriate bacterium concentration was OD600=0.3～0.4 around, and the co-cultivation time is about 8 minutes, co-cultured on the filter paper less for two days, and then, the explants were transferred onto the inducing medium. 4. There were twelve transgenic Fuji plantlets passed the kanamycin-resistant test. The kanamycin-resistant test of transgenic plantlets was based on the three main aspects:①The transgenic plantlets were able to be subcultured on media supplemented with 50mg/L kanamycin, continuously.②The leaf pieces of the transgenic plantlets showed as same regeneration ability on media containing 50mg/L kanamycin as on media without kanamycin.③The transgenic plantles were able to root normally on media supplemented with 50mg/L kanamycin.5. Choose the plantlets which pass the kanamycin-resistant test for tested by PCR, the result showed that eleven transgenic plantlets showed specific positive band as same as the plasmid control.And also made PCR-Southern blot for further tests, which proved that seventeen Gala and eleven Fuji also showed specific positive band as same as the plasmid, The result indicated that the Glu gene has been integrated into the gala apple genome. Then through RT-PCR, it proved that the Glu gene has been expressed more or less in seventeen Gala and expressed a little in three Fuji.6. The mycelia of Apple Ring Spot grew well under 24～28℃condition, and could generated conidiophores most. Adjusted culture medium pH to 5.0 and incubated under black light after inoculation could benefit to the conidiophore's generation. The removing of mycelia after their growth to some extent had significant promoting effect on the conidiophore's generation.7. After inoculated Apple Ring Spot, the vigor ofβ-1, 3-Glucanase, PAL and PPO in transformed plants were higher than untransformed plants, which proved that the transgenic plants were more disease-resistant.
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