Overexpression of a Novel Cytochrome P450 Promotes Flavonoid Biosynthesis and Osmotic Stress Tolerance in Transgenic Arabidopsis

Abstract

Flavonoids are mainly associated with growth, development, and responses to diverse abiotic stresses in plants. A growing amount of data have demonstrated the biosynthesis of flavonoids through multienzyme complexes of which the membrane-bounded cytochrome P450 supergene family shares a crucial part. However, the explicit regulation mechanism of Cytochrome P450s related to flavonoid biosynthesis largely remains elusive. In the present study, we reported the identification of a stress-tolerant flavonoid biosynthetic <i>CtCYP82G24</i> gene from <i>Carthamus tinctorius.</i> The transient transformation of <i>CtCYP82G24</i> determined the subcellular localization to the cytosol. Heterologously expressed <i>CtCYP82G24</i> was effective to catalyze the substrate-specific conversion, promoting the de novo biosynthesis of flavonoids in vitro. Furthermore, a qRT-PCR assay and the accumulation of metabolites demonstrated that the expression of <i>CtCYP82G24</i> was effectively induced by Polyethylene glycol stress in transgenic Arabidopsis. In addition, the overexpression of <i>CtCYP82G24</i> could also trigger expression levels of several other flavonoid biosynthetic genes in transgenic plants. Taken together, our findings suggest that <i>CtCYP82G24</i> overexpression plays a decisive regulatory role in PEG-induced osmotic stress tolerance and alleviates flavonoid accumulation in transgenic <i>Arabidopsis</i>.