Anthocyanins are the most conspicuous class of flavonoids
which present a large class of secondary plant metabolites.
Anthocyanins are important to many diverse functions within
plants.
Anthocyanin biosynthetic pathway is well established. Two
classes of genes required for anthocyanin biosynthesis have
been extensively characterized; the structural genes
encoding the enzymes that directly participate in the
formation of anthocyanins and other flavonoids, and the
regulatory genes that control the transcription of
structural genes. Light is one of the most important
environmental factors regulating plant development and genes
expression. Ultraviolet takes up 7% of sunlight and it
stimulates distinct responses in plant. Both UV-A and low
influence of UV-B can induce the accumulation of anthocyanin
via induction of the expression of anthocyanin biosynthesis
genes. Besides, the modulation of anthocyanin by
environmental and developmental factors has been observed. A
number of genes involved in anthocyanin biosynthesis are
induced by abiotic stresses.