title: Isolation and characterization of the fragrant cyclamen O-methyltransferase involved in flower coloration.
abstract: Anthocyanin O-methyltransferase (OMT) is one of the key enzymes for anthocyanin modification and flower pigmentation. We previously bred a novel red-purple-flowered fragrant cyclamen (KMrp) from the purple-flowered fragrant cyclamen 'Kaori-no-mai' (KM) by ion-beam irradiation. Since the major anthocyanins in KMrp and KM petals were delphinidin 3,5-diglucoside and malvidin 3,5-diglucoside, respectively, inactivation of a methylation step in the anthocyanin biosynthetic pathway was indicated in KMrp. We isolated and compared OMT genes expressed in KM and KMrp petals. RT-PCR analysis revealed that CkmOMT2 was expressed in the petals of KM but not in KMrp. Three additional CkmOMTs with identical sequences were expressed in petals of both KM and KMrp. Genomic PCR analysis revealed that CkmOMT2 was not amplified from the KMrp genome, indicating that ion-beam irradiation caused a loss of the entire CkmOMT2 region in KMrp. In vitro enzyme assay demonstrated that CkmOMT2 catalyzes the 3' or 3',5' O-methylation of the B-ring of anthocyanin substrates. These results suggest that CkmOMT2 is functional for anthocyanin methylation, and defective expression of CkmOMT2 is responsible for changes in anthocyanin composition and flower coloration in KMrp.
authors: Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma, 370-1292, Japan. akita.yusuke@jaea.go.jp
authors: Yusuke
authors: Y
authors: Akita
authors: Satoshi
authors: S
authors: Kitamura
authors: Yoshihiro
authors: Y
authors: Hase
authors: Issay
authors: I
authors: Narumi
authors: Hiroshi
authors: H
authors: Ishizaka
authors: Emiko
authors: E
authors: Kondo
authors: Naoko
authors: N
authors: Kameari
authors: Masayoshi
authors: M
authors: Nakayama
authors: Natsu
authors: N
authors: Tanikawa
authors: Yasumasa
authors: Y
authors: Morita
authors: Atsushi
authors: A
authors: Tanaka
mesh_terms: D000872:Anthocyanins / Q000096:biosynthesis* / Q000737:chemistry; D031824:Cyclamen / Q000201:enzymology* / Q000235:genetics / Q000528:radiation effects; D018744:DNA, Plant / Q000235:genetics; D035264:Flowers / Q000201:enzymology* / Q000235:genetics / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D018745:Genome, Plant / Q000235:genetics; D008745:Methylation; D008780:Methyltransferases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010802:Phylogeny; D010858:Pigmentation / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D018749:RNA, Plant / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D000872:Anthocyanins; D018744:DNA, Plant; D010940:Plant Proteins; D018749:RNA, Plant; C065861:malvidin; D008780:Methyltransferases; C017185:delphinidin