Cloning and Analysis of Promoter Regions of Flavonoid Biosynthesis Genes in Safflower

摘要

The flower of the safflower plant Carthamus tinctorius L. has been widely used in traditional Chinese medicine because of its ability to improve cerebral blood flow. Flavonoids are the main active ingredient of safflower plants. Analyses of the regulation of flavonoids are of great significance for the artificial regulation of their biosynthesis, and previous studies have mainly focused on their metabolic synthesis in safflower. For a better understanding of the regulation of flavonoid biosynthesis in safflower, promoters of flavonoid biosynthesis genes in safflower were cloned and analysed. First, the expression of the flavonoid genes in safflower was analysed. Twenty-four genes involved in flavonoid biosynthesis exhibited large differences. Four promoters of flavonoid genes that were mainly expressed in the flowers of safflower (termed pctCHI-1, pctCHS-2, pctF3H-2 and pctGT-1) were cloned and analysed. Elements that respond to light, i.e. phytohormones and the MYB regulator, were identified. The promoter activities were analysed using a protoplast system. All four promoters had activities in the flower protoplast, and the pctCHS-2 activity was the highest. Our results also demonstrate that pctCHS-2 is a flower-specific promoter. All of these results provide a basis for improved analyses of flavonoid regulation in safflower.