title: Agrobacterium tumefaciens AK-6b gene modulates phenolic compound metabolism in tobacco.
abstract: The 6b gene (AK-6b) of Agrobacterium tumefaciens AKE10 can substitute for the requirement of tobacco tissues for auxin and cytokinin to maintain callus growth in the culture medium. To identify compounds that might be involved in this process we analyzed phenolic metabolites in transgenic tobacco tissues expressing the AK-6b gene. On medium containing both cytokinin and auxin (SH medium), transgenic calli accumulated higher levels of chlorogenic acid, caffeoyl putrescine, rutin and kaempferol-3-rutinoside, than did wild-type tissues. In contrast, the levels of scopolin and its aglycone, scopoletin were lower in transgenic tissues. On hormone-free medium, these phenolic compounds showed neither significant levels nor an apparent relationship with AK-6b transcript levels, except for the negatively correlated levels of scopoletin and AK-6b transcripts. Apparently, the AK-6b gene acts, in SH medium, to redirect the synthesis of scopolin in tobacco tissues towards the preferential synthesis of caffeic acid derivatives and flavonoids.
authors.affiliation: Faculty of Bioresource Sciences, Akita Prefectural University, Nishi 241-7, Nakano-Aza Kaidobata, Akita 010-0195, Shimoshinjo, Japan.
authors.forename: Ivan
authors.initials: I
authors.lastname: Gális
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Kakiuchi
authors.forename: Petr
authors.initials: P
authors.lastname: Simek
authors.forename: Hiroetsu
authors.initials: H
authors.lastname: Wabiko
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics*; D003470:Culture Media / Q000737:chemistry; D046508:Culture Techniques / Q000379:methods; D015870:Gene Expression; D005798:Genes, Bacterial; D010636:Phenols / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D012313:RNA / Q000096:biosynthesis; D021241:Spectrometry, Mass, Electrospray Ionization; D014026:Nicotiana / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D003470:Culture Media; D010636:Phenols; D012313:RNA