Plant Metabolic Engineering, Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Council of Scientific and Industrial Research, Palampur 176061, Himachal Pradesh, India.
Mol Biotechnol. 2013 Feb;53(2):118-28. doi: 10.1007/s12033-012-9495-x.
This study was aimed at to check the influence of human lactoferrin (hLF) expression on iron homeostasis, flavonoids, and antioxidants in transgenic tobacco. Transgenic tobacco expressing hLF cDNA under the control of a CaMV 35S promoter was produced. The iron content as well as chlorophyll content of transgenic tobacco was lower compared to mock and untransformed wild plants. Interestingly, hLF transgenic tobacco showed higher level of transcript expression for genes related to iron content regulation like iron transporter and metal transporter. While expression of genes related to iron storage such as ferritin 1 and ferritin 2 was downregulated. The transcript expression of genes encoding antioxidant enzymes such as glutathione reductase, glutathione-S-transferase, ascorbate peroxidase, and catalase was downregulated in hLF transgenic tobacco compared to controls. Further, the transcript expression of two important genes encoding dihydroflavonol reductase (DFR) and phenylalanine ammonia lyase regulatory enzymes of flavonoid biosynthesis pathway was analyzed. The expression of DFR was found to be downregulated, while PAL expression was upregulated in hLF transgenic tobacco compared to mock and untransformed wild plant. Total phenolics, flavonoids, and proanthocyanidins contents were found to be higher in hLF transgenic tobacco than the mock and untransformed wild plant. Results suggest that hLF expression in transgenic tobacco leads to iron deficiency, downregulation of antioxidant enzymes, and increase in total flavonoids.
本研究旨在检测人乳铁蛋白（hLF）表达对转基因烟草中铁稳态、类黄酮和抗氧化剂的影响。通过 CaMV 35S 启动子控制下的 hLF cDNA 表达，产生了转基因烟草。与对照和未转化的野生植物相比，转基因烟草的铁含量和叶绿素含量较低。有趣的是，hLF 转基因烟草表现出更高水平的与铁含量调节相关的基因转录表达，如铁转运体和金属转运体。而铁储存相关基因，如铁蛋白 1 和铁蛋白 2 的表达则下调。与对照相比，hLF 转基因烟草中编码抗氧化酶的基因，如谷胱甘肽还原酶、谷胱甘肽-S-转移酶、抗坏血酸过氧化物酶和过氧化氢酶的转录表达下调。此外，还分析了两个重要基因编码二氢黄酮醇还原酶（DFR）和苯丙氨酸解氨酶的转录表达，它们是类黄酮生物合成途径的调节酶。与对照和未转化的野生植物相比，DFR 的表达下调，而 PAL 的表达上调。hLF 转基因烟草中的总酚、类黄酮和原花青素含量高于对照和未转化的野生植物。结果表明，hLF 在转基因烟草中的表达导致铁缺乏、抗氧化酶下调和总类黄酮增加。
