Genome-wide identification and expression profiles of flavonoid O-methyltransferase gene family in Scutellaria baicalensisOA

Background:Scutellaria baicalensis Georgi is a medicinal plant prized for its bioactive flavonoid derivatives.Flavonoid O-methyltransferases(OMTs)in this species play a vital role in enhancing these compounds’pharmacological activities,including their antioxidant,anti-inflammatory,and anticancer effects.However,a comprehensive genomic overview of the OMT gene family in S.baicalensis is lacking.Methods:This study conducted a genome-wide identification of the OMT gene family in S.baicalensis using bioinformatics approaches.The identified genes were characterized through phylogenetic,physicochemical,and structural analyses.Furthermore,the response of methoxylated flavonoids and key SbOMT genes to drought stress was investigated.Results:A total of 54 SbOMTs were identified and classified into 9 CCoAOMT and 45 COMT subfamily members.These proteins,with lengths from 129 to 695 amino acids and molecular weights from 14.42 to 76.94 kDa,were predominantly acidic.Subcellular localization predicted 43% to be cytoplasmic.Structurally,the CCoAOMT subfamily was more conserved than the COMT subfamily.Promoter analysis revealed hormone-and stress-responsive cis-elements.Under drought stress,the root content of methoxylated flavonoids(wogonin,wogonoside,and oroxylin A)decreased initially and then increased.The expression of SbOMT06,SbOMT41,SbOMT27,and SbOMT29 was positively correlated with this accumulation,suggesting their involvement in biosynthesis.Conclusion:This study provides foundational insights into the SbOMT gene family,revealing key candidates likely involved in methoxyflavonoid biosynthesis.The findings advance our understanding of the molecular mechanisms in S.baicalensis and offer valuable resources for future metabolic engineering and pathway optimization efforts.