[Suppression of apple polyphenol oxidase by double-stranded RNA (RNAi)].

Antisense and sense gene fragments (710 base pairs) of apple polyphenol oxidase (APPO) gene were obtained by RT-PCR amplification, using the total RNAs isolated from ripen apple fruit as the template. These two fragments were ligated with a 1000 bp spacer, YYT (crtW+crtY fusion) gene, which is relative to carotenoid synthesization in subcocci. The full-length 2446 bp-target gene was then inserted into plant binary vector pYPX145 to generate the recombinant plasmid pYF7704, which carried the expression unit, of APPO dsRNA. pYF7704 was transformed to apple (Malus x domestica) var. Red Fuji via agrobacterium tumefaciens mediated leaf disc transformation. With the selection of Karamycin and GUS detection assays, transgenic shoots of A PPO dsRNA were obtained. The results of FQ-RT-PCR indicated that APPO mRNA level was suppressed to 91.69% in transgenic shoots compared to wide shoots. The data suggested that dsRNAi technology on apple polyphenol oxidase is feasible to be utilized in transgenic shoots.