Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Republic of Korea.
J Microbiol Biotechnol. 2013 Dec;23(12):1737-46. doi: 10.4014/jmb.1307.07024.
IbMYB1, a transcription factor (TF) for R2R3-type MYB TFs, is a key regulator of anthocyanin biosynthesis during storage of sweet potatoes. Anthocyanins provide important antioxidants of nutritional value to humans, and also protect plants from oxidative stress. This study aimed to increase transgenic potatoes' (Solanum tuberosum cv. LongShu No.3) tolerance to environmental stress and enhance their nutritional value. Transgenic potato plants expressing IbMYB1 genes under the control of an oxidative stress-inducible peroxidase (SWPA2) promoter (referred to as SM plants) were successfully generated through Agrobacterium-mediated transformation. Two representative transgenic SM5 and SM12 lines were evaluated for enhanced tolerance to salinity, UV-B rays, and drought conditions. Following treatment of 100 mM NaCl, seedlings of SM5 and SM12 lines showed less root damage and more shoot growth than control lines expressing only an empty vector. Transgenic potato plants in pots treated with 400 mM NaCl showed high amounts of secondary metabolites, including phenols, anthocyanins, and flavonoids, compared with control plants. After treatment of 400 mM NaCl, transgenic potato plants also showed high DDPH radical scavenging activity and high PS II photochemical efficiency compared with the control line. Furthermore, following treatment of NaCl, UV-B, and drought stress, the expression levels of IbMYB1 and several structural genes in the flavonoid biosynthesis such as CHS, DFR, and ANS in transgenic plants were found to be correlated with plant phenotype. The results suggest that enhanced IbMYB1 expression affects secondary metabolism, which leads to improved tolerance ability in transgenic potatoes.
IbMYB1，作为 R2R3 型 MYB 转录因子家族的一个转录因子，是甘薯贮藏过程中花青素生物合成的关键调控因子。花青苷为人类提供了重要的有营养价值的抗氧化剂，同时也能保护植物免受氧化应激。本研究旨在提高转基因马铃薯（Solanum tuberosum cv. LongShu No.3）对环境胁迫的耐受性，并提高其营养价值。通过农杆菌介导的转化，成功获得了在氧化应激诱导型过氧化物酶（SWPA2）启动子控制下表达 IbMYB1 基因的转基因马铃薯植株（简称 SM 植株）。对两个有代表性的转基因 SM5 和 SM12 系进行了评估，以提高其对盐度、UV-B 射线和干旱条件的耐受性。用 100mM NaCl 处理后，SM5 和 SM12 系的幼苗表现出较少的根损伤和较多的茎生长，而仅表达空载体的对照系则表现出较少的根损伤和较多的茎生长。与对照植株相比，在 400mM NaCl 处理的盆载转基因马铃薯植株中，次生代谢物，包括酚类、花青素和类黄酮的含量较高。用 400mM NaCl 处理后，与对照系相比，转基因马铃薯植株的 DDPH 自由基清除活性和 PS II 光化学效率也较高。此外，在盐胁迫、UV-B 胁迫和干旱胁迫处理后，发现 IbMYB1 及其在类黄酮生物合成中的几个结构基因（CHS、DFR 和 ANS）在转基因植株中的表达水平与植株表型相关。结果表明，IbMYB1 表达增强影响次生代谢，从而提高转基因马铃薯的耐受力。
