Gene cloning of polyphenol oxidase from Salvia miltiorrhiza and its expression analysis

• 1、College of Life Sciences, Northwest A&F University, Yangling 712100

Abstract：In order to obtain the full-length sequence of polyphenol oxidase gene (PPO) and its expression in elicitor-treated hairy roots, it was cloned from hairy roots of Salvia miltiorrhiza Bunge by using RACE technique. The full length cDNA of PPO was 1930 bp with open reading frame 1770 bp, encoding a protein of 589 amino acids (GenBank No. KF712274). Bioinformatics analysis showed that the molecular weight of PPO gene was 65.8 kD with pI value 6.56, which had tryosinase family domain, but no trans-membrane helix or signal peptide. Both α-helix and β-sheet were found spreading in the whole polypeptide chain. Expression analysis of real-time PCR indicated that PPO transcript levels significantly increased in yeast extract (YE)-elicited hairy roots, whereas it significantly decreased in the other Ag+, ascorbic acid and cysteine treatments. In correspondingly, the accumulation of salvianolic acid B (SAB) was significantly increased in YE-treatment hairy roots, and was inhibited by the three elicitor treatments. These results suggest that PPO gene regulates the accumulation of SAB.

Keywords： Traditional Chinese Medicine Salvia miltiorrhiza polyphenol oxidase gene clone cDNA sequence gene expression