The anthocyanin biosynthesis pathway is a little complex with branches responsible for the synthesis of a variety of metabolites. In fruit tree crops, during the past decade, many structural genes encoding enzymes in the anthocyanin biosynthetic pathway and various regulatory genes encoding transcription factors that regulate the expression of structural genes have been cloned and then functionally characterized in detail. In general, the structural genes involved in anthocyanin synthesis were

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... oordinately expressed and their levels of expression were positively related to the degree of anthocyanin concentration; while, the coordinated expression pattern is striking a diverse among fruit crop species. Regulatory genes regulate spatiotemporally the structural genes and then form complicated metabolic network. Anthocyanin biosynthesis can be affected by external and internal factors, such as light, UV-B, low temperature and ABA through changes in expression of structural and regulatory genes.