Key Laboratory of Plant Cell engineering & germplasm creation, Ministry of Education, School of Life Science, Shandong University, Jinan, China.
Plant Biotechnol J. 2011 Feb;9(2):216-29. doi: 10.1111/j.1467-7652.2010.00548.x.
Stress resistance has repeatedly been enhanced in plants by the transfer of a single gene using genetic engineering. However, further enhancement of resistance to abiotic stress is still necessary. In our research, maize plants that were transgenic for both betA (encoding choline dehydrogenase from Escherichia coli) and TsVP (encoding V-H+ -PPase from Thellungiella halophila) were produced by cross-pollination. The existence of the transgenes in the pyramided plants was demonstrated by PCR and Southern blotting. The stable expression of transgenes was confirmed by real-time RT-PCR (reverse transcription polymerase chain reaction) analysis. An examination of the drought resistance characteristics demonstrated that the pyramided transgenic plants had higher glycinebetaine contents and H+ -PPase activity compared with the parental lines, which had either betA or TsVP, and contained higher relative water content (RWC), greater solute accumulation and lower cell damage under drought stress treatment. The pyramided plants grew more vigorously with less growth retardation, shorter anthesis-silking interval and higher yields than their parental lines and the wild-type. We concluded that co-expression of the two genes involved in different metabolism pathways in pyramided transgenic maize helped to improve the drought resistance over their parental lines that contained either single transgene. Our study suggests that the co-expression of multiple, effective genes in transgenic plants could effectively enhance the resistance to abiotic stress and provide a feasible approach for obtaining maize plants with improved drought resistance.
利用遗传工程将单个基因转入植物中，已反复提高了植物的抗逆性。然而，进一步提高植物对非生物胁迫的抗性仍然是必要的。在我们的研究中，通过杂交授粉生产了同时转基因 betA（编码大肠杆菌中的胆碱脱氢酶）和 TsVP（编码盐芥中的 V-H+-PPase）的玉米植株。通过 PCR 和 Southern 印迹证实了转基因在杂种中的存在。通过实时 RT-PCR（逆转录聚合酶链反应）分析证实了转基因的稳定表达。耐旱性特征的检查表明，与含有 betA 或 TsVP 的亲本系相比，转基因的杂种具有更高的甜菜碱含量和 H+-PPase 活性，并且在干旱胁迫处理下具有更高的相对含水量（RWC）、更大的溶质积累和更低的细胞损伤。与亲本系和野生型相比，转基因的杂种生长更旺盛，生长迟滞较少，开花吐丝间隔更短，产量更高。我们得出结论，在转基因玉米的杂种中共同表达涉及不同代谢途径的两个基因有助于提高其对亲本系的耐旱性，而亲本系仅含有单个转基因。我们的研究表明，在转基因植物中共同表达多个有效的基因可以有效提高植物对非生物胁迫的抗性，并为获得耐旱性改良的玉米植株提供了一种可行的方法。
