Molecular Characterization of an Isoflavone 2'-Hydroxylase Gene Revealed Positive Insights into Flavonoid Accumulation and Abiotic Stress Tolerance in Safflower

• Published in: Molecules (Basel, Switzerland) Switzerland), 2022-11, Vol.27 (22), p.8001
• Main Authors: Liu, Jianyu, Ahmad, Naveed, Hong, Yingqi, Zhu, Meihua, Zaman, Shah, Wang, Nan, Yao, Na, Liu, Xiuming
• Format: Article
• Language: English
• Subjects: Abiotic stress; Accumulation; Activating transcription factor 3; Amino acids; Arabidopsis - metabolism; Biosynthesis; Carthamus tinctorius; Carthamus tinctorius - genetics; Carthamus tinctorius - metabolism; Cellular stress response; constitutive expression; CYP81E8; Cytochrome; Dark adaptation; Enzymes; Evolution; Fatty acids; flavonoid biosynthesis; Flavonoids; Flavonoids - metabolism; Flowering; Flowers & plants; Gene expression; Gene Expression Regulation, Plant; Gene regulation; Genes; Genomes; Hormones; Hydroxylase; isoflavone 2′-hydroxylase; Isoflavones; Metabolites; Methyl jasmonate; Phylogenetics; Phylogeny; Plant growth; Polyethylene glycol; Proteins; Regulation; safflower; Secondary metabolites; Stress, Physiological - genetics; Topology; transgenic Arabidopsis
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules27228001

Flavonoids with significant therapeutic properties play an essential role in plant growth, development, and adaptation to various environments. The biosynthetic pathway of flavonoids has long been studied in plants; however, its regulatory mechanism in safflower largely remains unclear. Here, we carried out comprehensive genome-wide identification and functional characterization of a putative gene encoding an isoflavone 2'-hydroxylase from safflower. A total of 15 genes were identified from the safflower genome. Phylogenetic classification and conserved topology of gene structures, protein motifs, and cis-elements elucidated crucial insights into plant growth, development, and stress responses. The diverse expression pattern of genes in four different flowering stages suggested important clues into the regulation of secondary metabolites. Similarly, the variable expression of during multiple flowering stages further highlighted a strong relationship with metabolite accumulation. Furthermore, the orchestrated link between transcriptional regulation of and flavonoid accumulation was further validated in the yellow- and red-type safflower. The spatiotemporal expression of under methyl jasmonate, polyethylene glycol, light, and dark conditions further highlighted its likely significance in abiotic stress adaption. Moreover, the over-expressed transgenic Arabidopsis lines showed enhanced transcript abundance in OE-13 line with approximately eight-fold increased expression. The upregulation of , , and genes and the detection of several types of flavonoids in the OE-13 transgenic line also provides crucial insights into the potential role of during flavonoid accumulation. Together, our findings shed light on the fundamental role of encoding a putative isoflavone 2'-hydroxylase via constitutive expression during flavonoid biosynthesis.