Differential expression of two flavonoid 3'-hydroxylase cDNAs involved in biosynthesis of anthocyanin pigments and 3-deoxyanthocyanidin phytoalexins in sorghum [Sorghum bicolor]

• Published in: Plant and cell physiology 2006-10, Vol.47 (10), p.1412-1419
• Main Authors: Shin, C.H.(University of Hong Kong (China)), Chu, I.K, Yip, W.K, Lo, C
• Format: Article
• Language: English
• Subjects: ADN; Amino Acid Sequence; ANTHOCYANE; ANTHOCYANINS; Anthocyanins - biosynthesis; Anthocyanins - chemistry; ANTOCIANINAS; Cytochrome P-450 Enzyme System - biosynthesis; Cytochrome P-450 Enzyme System - genetics; DNA; DNA, Complementary - analysis; FLAVONOIDE; FLAVONOIDES; FLAVONOIDS; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Genes, Plant; HYDROXYLATION; IDROXILACION; Mixed Function Oxygenases - biosynthesis; Mixed Function Oxygenases - genetics; Molecular Sequence Data; Molecular Structure; Sesquiterpenes; Sorghum - genetics; SORGHUM BICOLOR; Terpenes - chemistry; Terpenes - metabolism
• ISSN: 0032-0781; 1471-9053
• DOI: 10.1093/pcp/pcl003

Three unique sorghum flavonoid 3'-hydroxylase (F3'H) cDNAs (SbF3'H1, SbF3'H2 and SbF3'H3) were discovered through bioinformatics analysis. Their encoded proteins showed >60% identity to the Arabidopsis TT7 (F3'H) protein. Overexpression of SbF3'H1 or SbF3'H2 restored the ability of tt7 mutants to produce 3'-hydroxylated flavonoids, establishing their roles as functional F3'H enzymes. In sorghum mesocotyls, SbF3'H1 expression was involved in light-specific anthocyanin accumulation while SbF3'H2 expression was involved in pathogen-specific 3-deoxyanthocyanidin synthesis. No SbF3'H3 expression was detected in all tissues examined. The sorghum mesocotyls represent a good system for investigation of differential regulation of F3'H genes/alleles responding to different external stimuli.