State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, 271018, PR China.
J Biotechnol. 2013 Feb 10;163(3):281-91. doi: 10.1016/j.jbiotec.2012.11.008. Epub 2012 Nov 23.
Expansins are the key regulators of cell wall extension during plant growth. Previously, we produced transgenic tobacco plants with increased tolerance to water stress by overexpressing the wheat expansin gene TaEXPB23 driven by the constitutive 35S cauliflower mosaic virus (CaMV) promoter. However, the growth and development of 35S::TaEXPB23 transgenic tobacco plants were altered under normal growth conditions, with a faster growth rate at the seedling stage, earlier flowering and maturation, and a shorter plant height compared to WT. In the current study, we determined that cellular characteristics and carbohydrate metabolism were altered in 35S::TaEXPB23 transgenic tobacco plants. We also generated transgenic Arabidopsis plants using the same vector. The transgenic Arabidopsis plants had the same phenotype as the transgenic tobacco plants, which may have resulted from the altered expression of several flowering-related genes. We then produced TaEXPB23 transgenic tobacco plants using the stress-inducible RD29A promoter. The use of this promoter reduced the negative effects of TaEXPB23 on plant growth and development. The RD29A::TaEXPB23 transgenic tobacco plants had greater tolerance to water stress than WT, as determined by examining physiological and biochemical parameters. Therefore, the use of stress-inducible promoters, such as RD29A, may minimize the negative effects of constitutive transgene expression and improve the water-stress tolerance of plants.
扩展蛋白是植物生长过程中细胞壁延伸的关键调节因子。此前，我们通过过表达小麦扩展蛋白基因 TaEXPB23 并利用组成型 35S 花椰菜花叶病毒 (CaMV) 启动子驱动，生产出对水分胁迫具有更高耐受性的转基因烟草植物。然而，35S::TaEXPB23 转基因烟草植物在正常生长条件下的生长和发育发生了改变，与 WT 相比，幼苗期生长速度更快，开花和成熟更早，株高更短。在本研究中，我们确定 35S::TaEXPB23 转基因烟草植物的细胞特征和碳水化合物代谢发生了改变。我们还使用相同的载体生成了转基因拟南芥植物。转基因拟南芥植物与转基因烟草植物具有相同的表型，这可能是由于几个与开花相关的基因表达发生改变所致。然后，我们使用应激诱导的 RD29A 启动子生产 TaEXPB23 转基因烟草植物。使用该启动子减少了 TaEXPB23 对植物生长和发育的负面影响。通过检查生理和生化参数，RD29A::TaEXPB23 转基因烟草植物比 WT 具有更高的水分胁迫耐受性。因此，使用应激诱导型启动子（如 RD29A）可能会最小化组成型转基因表达的负面影响，并提高植物的水分胁迫耐受性。
