Verberne Marianne C, Sansuk Kamonchanok, Bol John F, Linthorst Huub J M, Verpoorte Robert
Institute of Biology Leiden, Section Plant Metabolomics, Gorlaeus Laboratories, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands.
J Biotechnol. 2007 Jan 30;128(1):72-9. doi: 10.1016/j.jbiotec.2006.09.005. Epub 2006 Sep 23.
Phylloquinone (Vitamin K(1)) is an essential component of the photosynthetic electron transfer. As isochorismate is required for the biosynthesis of Vitamin K(1), isochorismate synthase (ICS) activity is expected to be present in all green plants. In bacteria salicylic acid (SA) is synthesized via a two step pathway involving ICS and isochorismate pyruvate lyase (IPL). The effect of the introduction in tobacco plants of the bacterial ICS and IPL genes on the endogenous isochorismate pathway was investigated. Transgenic tobacco plants in which IPL was targeted to the chloroplast suffered severe growth retardation and had low Vitamin K(1) content. Probably because isochorismate was channeled towards SA production, the plants were no longer able to produce normal levels of Vitamin K(1). Transgenic tobacco plants in which the bacterial ICS was present in the chloroplast showed higher Vitamin K(1) contents than wild type plants.
叶绿醌（维生素K(1)）是光合电子传递的重要组成部分。由于维生素K(1)的生物合成需要异分支酸，预计所有绿色植物中都存在异分支酸合酶（ICS）活性。在细菌中，水杨酸（SA）通过一个涉及ICS和异分支酸丙酮酸裂解酶（IPL）的两步途径合成。研究了将细菌ICS和IPL基因导入烟草植物对其内源异分支酸途径的影响。IPL定位于叶绿体的转基因烟草植物生长严重受阻，维生素K(1)含量较低。可能是因为异分支酸被用于SA的产生，这些植物不再能够产生正常水平的维生素K(1)。叶绿体中存在细菌ICS的转基因烟草植物比野生型植物表现出更高的维生素K(1)含量。
