Gális Ivan, Kakiuchi Yasutaka, Simek Petr, Wabiko Hiroetsu
Faculty of Bioresource Sciences, Akita Prefectural University, Nishi 241-7, Nakano-Aza Kaidobata, Akita 010-0195, Shimoshinjo, Japan.
Phytochemistry. 2004 Jan;65(2):169-79. doi: 10.1016/j.phytochem.2003.10.015.
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.
根癌农杆菌AKE10的6b基因（AK-6b）可以替代烟草组织对生长素和细胞分裂素的需求，以维持培养基中愈伤组织的生长。为了鉴定可能参与此过程的化合物，我们分析了表达AK-6b基因的转基因烟草组织中的酚类代谢产物。在含有细胞分裂素和生长素的培养基（SH培养基）上，转基因愈伤组织积累的绿原酸、咖啡酰腐胺、芦丁和山奈酚-3-芸香糖苷水平高于野生型组织。相反，转基因组织中东莨菪苷及其苷元东莨菪素的水平较低。在无激素培养基上，除了东莨菪素和AK-6b转录本水平呈负相关外，这些酚类化合物的水平既不显著，也与AK-6b转录本水平没有明显关系。显然，在SH培养基中，AK-6b基因的作用是将烟草组织中东莨菪苷的合成导向优先合成咖啡酸衍生物和类黄酮。
