The Functional Characterization Of PyMYB10.1 Regulating Anthocyanin Biosynthesis In Pear

Pear is one of the main fruits in China, which has rich varieties. Because of its beautiful color, the red pear enables many customers to love and has a good market prospect. Meanwhile, the anthocyanin biosynthesis and accumulation in its peel cause the red pear coloring. Compared with other plants, the research on relative genes of anthocyanin biosynthesis in pear is started lately, so the problem about the mechanism of red pigment in red pear needs to be further gone into. In the previous study, we have obtained a MYB gene PyMYB10.1 for regulating anthocyanin biosynthesis when cloning the gene PyMYB10 from ‘aoguan’. Thus, we identify the gene’s biological function in this paper. The main results are shown as follows:1. By sequence analysis, The gene Py MYB10.1 was 714 bp full length cDNA. The predicted protein of gene had 237 amino acids, with a calculated molecular mass of 27.4 kD and an isoelectric point of 8.78.2. The amino acid sequence comparative analysis showed that the conserved R2R3 domain was observed in the N-amino terminus of PyMYB10.1. A signature motif specific for the interaction between MYB and bHLH proteins was observed in the R3 domain. These were similar with other MYB transcription factors regulating anthocyanin biosynthesis.3. The NCBI Blast revealed that the PyMYB10.1 was close with other MYB10 transcription factors regulating anthocyanin biosynthesis, and the consistency was 49% with MdMYB10 in apple and 51% with PyMYB10 in pear.4. The phylogenetic analysis showed that the PyMYB10.1 had close genetic relationship with anthocyanin activators, such as the MdMYB10 in apple, the PyMYB10 in pear, and the FaMYB10 in strawberry. But it was far with anthocyanin repressors, proanthocyanidins and flavonols regulators, such as the FaMYB1, the MdMYB17, the MdMYB9, the VvMYBPA2, the AtMYB12 and the VvMYBF1.5. The expression analysis revealed that the transcript levels of PyMYB10.1 in flower, leaf, and fruit skin were higher than in fruit cortex. In pear skins, the similar transcripts of PyMYB10.1 and PyMYB10 were detected. The expression level of PyMYB10.1 was highly correlated with the concentration of anthocyanin in peel after shading treatment and MeJA treatment.6. The results of yeast two-hybrid, BiFC assay and tobacco transient-expression assay indicated that the PyMYB10.1 and PyMYB10 had a single function or interacted with bHLHs to activate the AtDFR promoter. Furthermore, the regulation of AtDFR was enhanced when MYBs combined with the bHLHs. So, the mechanism could increase the anthocyanin accumulation in pears.Based on the results, we concluded that the PyMYB10.1 was the homologous gene of PyMYB10 and was important positive regulation factor in anthocyanin biosynthesis, meanwhile, it could response the illumination and MeJA. The PyMYB10.1 and PyMYB10 could interact with bHLHs to activate the expression of anthocyanin structural gene, then enhanced anthocyanin biosynthesis.