关键词: 梨, 花青苷, PyMYBa

Abstract: The 714 bp full length cDNA of PyMYBa gene was obtained using RT and RACE PCR from pear skins. The predicted protein of PyMYBa had 237 amino acids，with a calculated molecular mass of 27.4 kD and an isoelectric point of 8.78. The conserved R2R3 domain was observed in the N-amino terminus of PyMYBa. A signature motif specific for the interaction between MYB and bHLH proteins was observed in the R3 domain. Phylogenetic analysis revealed that PyMYBa is close with other MYB TFs involved in anthocyanin biosynthesis. Transcription analyses revealed that higher transcript levels of PyMYBa were in flower，leaf，fruit peel than in fruit flesh. In pear skins，the similar transcripts of PyMYBa and PyMYB10 were detected. The expression level of PyMYBa is highly correlated with the concentration of anthocyanin in peel after shading treatment and MeJA treatment. Therefore，the PyMYBa is speculated to be a positive MYB transcription factor gene regulating the biosynthesis of anthocyanin in pear. Through a prokaryotic expression system，the recombinant protein of PyMYBa was obtained，whose molecular weight was consistent with the size of expected protein.

Key words: pear, anthocyanin, PyMYBa