Genome-wide identification and analysis of the cytochrome P450 family elucidate flavonoid biosynthesis in safflower.

Safflower (Carthamus tinctorius L.) has been widely utilized for oil production, textile dyeing and traditional medicinal application. Flavonoids constitute the predominant secondary metabolites in safflower, demonstrating significant cardioprotective effects. Cytochrome P450 enzymes (CYPs), crucial regulators of plant growth and secondary metabolite biosynthesis including flavonoids, remain poorly characterized in safflower despite their established roles in other species. In this study, we systematically identified 271 CYP genes from the safflower genome and comprehensively analyzed their physicochemical properties, the phylogenetic relationships, gene structures, chromosomal distributions, syntenic relationships, and tissue-specific expression patterns. Results reveal the 271 CtCYPs genes are separated into 31 different families attributing to 8 clans based on phylogenetic relationship and sequence similarity. Through integrated analysis of tandem duplication events, comparative genomics, and correlation studies between gene expression and flavonoid accumulation, we ultimately identified four key CYP candidate genes (CtCYP89A1, CtCYP82C2, CtCYP71A4, and CtCYP93A6) potentially involved in the biosynthesis of flavonoid compounds in Carthamus tinctorius. Our findings provide critical gene resources for developing high flavonoids in flowers of safflower cultivars through targeted breeding strategies.