Dynamic Changes of Key Enzymes in Crocin Biosynthesis During Stigma Development and Their Modulation by Red/Far-Red Light
This study aimed to elucidate the mechanisms underlying red/far-red and blue light regulation of crocin biosynthesis during pistil development in Crocus sativus. Our findings demonstrated that red light significantly enhanced the accumulation of crocin and picrocrocin in stigmas at anthesis compared to control conditions. Gene expression analysis revealed upregulation of key carotenoid biosynthetic genes, including PSY, ZDS, and LCYB, in response to red/far-red light treatment. Furthermore, investigation of photoreceptor-related genes (PHYA/B, CRY) and light signaling components (COP1, PIF) suggested that red/far-red light promotes HY5-mediated carotenoid biosynthesis through PHY-dependent suppression of COP1 and PIF. Notably, the expression of NCED and ZED genes involved in the ABA biosynthetic pathway remained unaffected. These results provide novel insights into the photoregulatory mechanisms governing crocin biosynthesis in C. sativus.