Relationship between Sucrose Metabolism and Anthocyanin Biosynthesis During Ripening in Chinese Bayberry Fruit

Two cultivars of Chinese bayberry fruit cvs ‘Dongkui’ and ‘Biqi’ with five different ripening stages were used to investigate the relationship between anthocyanin biosynthesis and sugar metabolism during fruit development. The results showed that anthocynin accumulated with the increased ripening stage in both of the two cultivars of bayberries. As compared to ‘Biqi’ fruit, a higher level of anthocyanin content was observed in ‘Dongkui’ fruit due to the increased expression of anthocyanin biosynthetic and regulatory genes especially <i>MrCHI</i>, <i>MrDFR1</i>, <i>MrANS</i>, and <i>MrMYB1</i>. Meanwhile, ‘Dongkui’ fruit also experienced higher levels of soluble sugars including sucrose, glucose, and fructose and expression of genes such as <i>MrSPS1</i>, <i>MrSPS2</i>, <i>MrSPS3</i>, <i>MrINV1</i>, <i>MrINV2</i>, and <i>MrINV3</i> involved in sugar metabolism. Correlation analysis showed anthocyanin content had a significant relationship with all the three soluble sugars in bayberry fruit. Therefore, our results suggested that the higher anthocyanin content in ‘Dongkui’ fruit might be associated with its increased levels of soluble sugars