CtMYB1 regulate flavonoid biosynthesis in safflower flower by binding the CAACCA elements

Background Safflower ( Carthamus tinctorius L.) is a valuable crop known for its flowers, which are rich in flavonoids and are used for promoting blood circulation and preventing atherosclerosis. However, the molecular regulation of flavonoid biosynthesis in safflower is still poorly understood. In this study, we identified a AtMYB12 homologous gene, CtMYB1 , in safflower and characterized its sequence. The flower protoplast transient expression system and virus-induced gene silence (VIGS) technique were established in safflower and we tested the role of CtMYB1 in the regulation of flavonoid biosynthesis. Results Flower protoplast transient expression showed that flavonoid biosynthesis genes CtC4H2 , CtF3H4 , and CtHCT12 were upregulated after transfection with CtMYB1 . Meanwhile, VIGS showed that the transfected petals were lighter in color, and there was a decrease in the amount of the major component Hydroxysafflor yellow A (HSYA) compared to the control. Additionally, the interaction analysis by the use of Biacore system revealed that CtMYB1 can bind to the CAACCA element of flavonoid biosynthesis genes promoters. Conclusions CtMYB1 can regulate flavonoid biosynthesis in safflower flower by binding the CAACCA elements of flavonoid biosynthesis related genes promoters,which shed light on the molecular regulation of flavonoid biosynthesis in safflower.The establishment of the flower protoplast expression system and VIGS in safflower provide a valuable tool for studying gene function, particularly those involved in the regulation and biosynthesis of-active compounds of safflower.