Rahman Laiq ur, Kouno Hitomi, Hashiguchi Yuya, Yamamoto Hirobumi, Narbad Arjan, Parr Adrian, Walton Nicholas, Ikenaga Toshihiko, Kitamura Yoshie
School of Pharmaceutical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, Japan.
Bioresour Technol. 2009 Oct;100(20):4836-42. doi: 10.1016/j.biortech.2009.04.035. Epub 2009 May 19.
As part of a study to explore the potential for new or modified bio-product formation, Beta vulgaris (sugar beet) has been genetically modified to express in root-organ culture a bacterial gene of phenylpropanoid catabolism. The HCHL gene, encoding p-hydroxycinnamoyl-CoA hydratase/lyase, was introduced into B. vulgaris under the control of a CaMV 35S promoter, using Agrobacterium rhizogenes LBA 9402. Hairy root clones expressing the HCHL gene, together with non-expressing clones, were analysed and revealed that one expression-positive clone accumulated the glucose ester of p-hydroxybenzoic acid (pHBA) at about 14% on a dry weight basis. This is the best yield achieved in plant systems so far. Determination of cell-wall components liberated by alkaline hydrolysis confirmed that the ratio of pHBA to ferulic acid was considerably higher in the HCHL-expressing clones, whereas only ferulic acid was detected in a non-expressing clone. The change in cell-wall components also resulted in a decrease in tensile strength in the HCHL-expressing clones.
作为一项探索新的或改良生物产品形成潜力的研究的一部分，甜菜已被基因改造，以便在根器官培养中表达一种苯丙烷类分解代谢的细菌基因。编码对羟基肉桂酰辅酶A水合酶/裂解酶的HCHL基因，在花椰菜花叶病毒35S启动子的控制下，利用发根农杆菌LBA 9402导入甜菜。对表达HCHL基因的毛状根克隆以及不表达的克隆进行了分析，结果显示，一个表达阳性克隆以干重计积累了约14%的对羟基苯甲酸（pHBA）葡萄糖酯。这是迄今为止在植物系统中获得的最佳产量。对碱性水解释放的细胞壁成分的测定证实，在表达HCHL的克隆中，pHBA与阿魏酸的比例显著更高，而在一个不表达的克隆中仅检测到阿魏酸。细胞壁成分的变化也导致表达HCHL的克隆的拉伸强度降低。
