Regeneration In Vitro And Disease-Resistant Gene Transformation Of Strawberry

Shoot in vitro regeneration of strawberry cultivars " Toyonoka " and "Allstar " were investigated. The result showed that several factors affected regeneration ratio of strawberry including strawberry genotype, phytohormone concentrations and combinations, the type of the nutrient medium, pH value, explants types and ways that leaves touched medium. A rapid and efficient regeneration system of "Allstar" strawberry was established. By using leaves co-cultivation with Agrobacterium, an optimal transformation system was obtained. Putative transgenic "Allstar" strawberry plants containing the npt II, chiSB genes were obtained based on this system.Because of different genotype, strawberry regeneration potency is different. The result of leaves regeneration showed that the shoot regeneration frequency of strawberry cultivar " Allstar " was higher than that " Toyonoka ". And the efficiency of regeneration depended on the combination of phytohormones and the type of the nutrient medium. MS produced the higher shoot regeneration ratio than that of MS minerals and B5 vitamins, but there was no evident difference. PH value , explants types and ways that leaves touched medium had effect on shoot regeneration of "Allstar" strawberry. Optimal pH value was 5.8. Leaves showed a much higher regeneration ratio than that of petiole segements. Shoot regeneration ratio between ways that leaves touched medium had evident difference, leaves that back side touched medium had high regeneration ratio. MS medium supplemented with 2.0mg/lBA, 0.2mg/lNAA, sucrose 3%, agar 10% and pH 5.8 was the optimal medium condition of shoot regeneration of "Allstar" strawberry, the regeneration ratio is 64%.On the basis of regeneration system of "Allstar" leaves , investigation was conducted on genetic transformation of "Allstar" strawberry by using Agrobacterium-mediated method and factors affecting transformation was also discussed in detail. The optimal concentration of kanamycin to "Allstar" leaves and shoot were 30mg/l and of carbenicillin is 450mg/l , Regeneration ratio of shoot improved by adding of AS to regeneration medium. The ideal time for leaves dipping in Agrobacterium is 10-15 minutes and the optimal co-cultivation is 3 days. Putative transformed resistant shoot of "Allstar" were obtained under above conditions, the transformation ratio is 1.1%.