Abstract:

In order to investigate the molecular structures of polyphenol oxidase (PPO) in Yali, we designed series of primers based on the known cDNA fragment of PPO gene in Yali to clone the unknown 3’ and 5’ cDNA terminal sequence for this gene by using RACE method. With the total RNA extracted from fruit of Yali as the template, we finally obtained the full length cDNA sequence of PPO gene in Yali, which is 2126 bp in length, and has a open reading frame between 136-1917 bp, in which 276 predicted amino acid residues were encoded. Research the deduce amino acids of PPO gene from Yali by bioinformatics analysis, it showed that the PPO in Yali was a typical hydrophilic soluble protein which belonged to tyrosinase super family, and it does not contain distinct transmembrane domain in tertiary structure, so the Yali PPO should located in thylakoid lume of plastid. That information laid a good foundation for regulating the enzyme activity of PPO in Yali by biological technology and breeding a new cultivar of pear with browning resistance in the future.