Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics & Biotechnology, Ministry of Education, Nanjing Forestry University. Nanjing, 210037, China; Nanjing Key Laboratory of Quality and Safety of Agricultural Products, Nanjing Xiaozhuang University, Nanjing, 211171, China.
Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics & Biotechnology, Ministry of Education, Nanjing Forestry University. Nanjing, 210037, China.
Plant Physiol Biochem. 2019 Sep;142:94-105. doi: 10.1016/j.plaphy.2019.05.034. Epub 2019 Jun 10.
1-Deoxy-D-xylulose-5-phosphate synthasse (DXS) and 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) are key enzymes in terpenoid biosynthesis. DXS catalyzes the formation of 1-deoxy-D-xylulose 5-phosphate (DXP) from pyruvate and D-glyceraldehyde-3-phosphate. DXR catalyzes the formation of 2-C-methyl-D-erythritol 4-phosphate (MEP) from DXP. Previous studies of the DXS and DXR genes have focused on herbs, such as Arabidopsis thaliana, Salvia miltiorrhiza, and Amomum villosum, but few studies have been conducted on woody plants. For that reason, we chose Populus trichocarpa as a model woody plant for investigating the DXS and DXR genes. PtDXS exhibited the highest expression level in leaves and the lowest expression in roots. PtDXR showed maximum expression in young leaves, and the lowest expression in mature leaves. The expression profiles revealed by RT-PCR following different elicitor treatments such as abscisic acid, NaCl, PEG, HO, and cold stress showed that PtDXS and PtDXR were elicitor-responsive genes. Our results showed that the PtDXS gene exhibited diurnal changes, but PtDXR did not. Moreover, overexpression of PtDXR in transgenic poplars improved tolerance to abiotic and biotic stresses. Those results showed that the PtDXR encoded a functional protein, and widely participates in plant growth and development, stress physiological process.
1-脱氧-D-木酮糖-5-磷酸合酶（DXS）和 1-脱氧-D-木酮糖-5-磷酸还原异构酶（DXR）是萜类生物合成中的关键酶。DXS 催化丙酮酸和 D-甘油醛-3-磷酸生成 1-脱氧-D-木酮糖 5-磷酸（DXP）。DXR 催化 DXP 生成 2-C-甲基-D-赤藓醇 4-磷酸（MEP）。以前对 DXS 和 DXR 基因的研究集中在草本植物，如拟南芥、丹参和砂仁上，但对木本植物的研究较少。因此，我们选择毛白杨作为研究 DXS 和 DXR 基因的模式木本植物。PtDXS 在叶片中表达水平最高，在根中表达水平最低。PtDXR 在幼叶中表达量最大，在成熟叶中表达量最低。RT-PCR 表达谱分析显示，PtDXS 和 PtDXR 是受不同诱导剂（如脱落酸、NaCl、PEG、HO 和冷胁迫）诱导的基因。我们的研究结果表明，PtDXS 基因表现出昼夜变化，但 PtDXR 没有。此外，在转基因杨树中过表达 PtDXR 可提高对非生物和生物胁迫的耐受性。这些结果表明，PtDXR 编码一种功能性蛋白，广泛参与植物生长发育和胁迫生理过程。
