Department of Secondary Metabolism, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120 Halle (Saale), Germany.
Phytochemistry. 2010 Jul;71(10):1076-84. doi: 10.1016/j.phytochem.2010.04.007. Epub 2010 May 5.
A dsRNAi approach silencing a key enzyme of sinapate ester biosynthesis (UDP-glucose:sinapate glucosyltransferase, encoded by the UGT84A9 gene) in oilseed rape (Brassica napus) seeds was performed to reduce the anti-nutritive properties of the seeds by lowering the content of the major seed component sinapine (sinapoylcholine) and various minor sinapate esters. The transgenic seeds have been produced so far to the T6 generation and revealed a steady suppression of sinapate ester accumulation. HPLC analysis of the wild-type and transgenic seeds revealed, as in the previous generations, marked alterations of the sinapate ester pattern of the transformed seeds. Besides strong reduction of the amount of the known sinapate esters, HPLC analysis revealed unexpectedly the appearance of several minor hitherto unknown rapeseed constituents. These compounds were isolated and identified by mass spectrometric and NMR spectroscopic analyses. Structures of 11 components were elucidated to be 4-O-glucosides of syringate, caffeyl alcohol and its 7,8-dihydro derivative as well as of sinapate and sinapine, along with sinapoylated kaempferol glycosides, a hexoside of a cyclic spermidine alkaloid and a sinapine derivative with an ether-bridge to a C(6)-C(3)-unit. These results indicate a strong impact of the transgenic approach on the metabolic network of phenylpropanoids in B. napus seeds. Silencing of UGT84A9 gene expression disrupt the metabolic flow through sinapoylglucose and alters the amounts and nature of the phenylpropanoid endproducts.
采用 dsRNAi 方法沉默油菜（Brassica napus）种子中合成芥子酸酯的关键酶（UDP-葡萄糖：芥子酰葡萄糖基转移酶，由 UGT84A9 基因编码），以降低种子中主要成分芥子碱（芥子酰胆碱）和各种次要芥子酸酯的含量，从而降低其抗营养特性。迄今为止，已将这些转基因种子生产到 T6 代，并且发现芥子酸酯的积累得到了稳定的抑制。对野生型和转基因种子的 HPLC 分析表明，与前几代一样，转化种子的芥子酸酯模式发生了明显改变。除了明显减少已知芥子酸酯的含量外，HPLC 分析还出人意料地发现了几种以前未知的油菜籽成分。通过质谱和 NMR 光谱分析对这些化合物进行了分离和鉴定。通过结构解析，鉴定出 11 种成分分别为丁香酸、咖啡醇及其 7,8-二氢衍生物以及芥子酸和芥子碱的 4-O-葡萄糖苷，以及芥子酰化山奈酚糖苷、一种环状亚精胺生物碱的六糖苷和一种具有醚桥到 C(6)-C(3)-单元的芥子碱衍生物。这些结果表明，转基因方法对油菜种子中苯丙烷代谢网络产生了强烈影响。UGT84A9 基因表达的沉默破坏了通过芥子酰葡萄糖的代谢流，并改变了苯丙烷终产物的数量和性质。
