Research on overexpression of PsG6PDH gene from Populus suaveolens to improve cold and freezing tolerance of tobacco plants | 甜杨PsG6PDH基因超表达对提高烟草抗寒冻性的影响

Chinese. 研究甜杨葡萄糖-6-磷酸脱氢酶（PsG6PDH）基因超表达对烟草抗寒冻性的影响，为烟草的抗寒冻育种提供理论依据。构建甜杨PsG6PDH基因的植物表达载体pBGⅠ，采用叶盘转化法转化烟草，对转化烟草植株低温驯化后的形态、生理生化指标进行测定与分析。PCR检测及Southern杂交结果显示，甜杨PsG6PDH基因已整合到转基因烟草的基因组中。低温试验表明，未经冷驯化的对照烟草较转基因烟草早出现萎蔫，恢复正常生长也较晚；经过冷驯化在接近0 ℃处理24 h的对照烟草叶片基本萎蔫，而转基因烟草仍然正常。在0 ℃及更低温度胁迫下，转基因烟草的相对电导率一直保持在35%左右，而对照烟草的相对电导率则从35%上升到90%；随着胁迫时间的延长，转基因烟草的SOD、POD活性升高，而MDA含量下降。甜杨PsG6PDH基因能够提高植物的抗寒冻性，可以作为改良植物抗寒冻性的新的外源基因。

English. Effects on tobacco plants by overexpression of PsG6PDH gene from P. suaveolens were studied in this paper, which might provide theoretical-basis for the genetic cold tolerance and freezing resistance in plants. The gene PsG6PDH was constructed into binary vector pBI121 and transformed into tobacco plants by leaf disc method, and the indexes of physiology and biochemistry in transgenic lines were determined under low temperature stress. PCR and Southern blotting results verified integration of this gene into the genome of tobacco. Moreover, cold treatment experiments showed that without cold acclimation wild-type tobaccos suffered or resumed from cold injury earlier or later than transgenic lines. After cold acclimation, wild-type tobaccos greatly suffered from cold injury while transgenic lines were normal after 0 ℃ treatment for 24 h. During 0 ℃ to even low temperature, the relative leakage data of transgenic lines steadily stayed on approximately 35%, while that of wild-type lines increased from approximately 35% to 90%. In addition, SOD, POD activities were increasing while MDA content was decreasing with the time extending under cold stress. The poplar gene PsG6PDH could result in the low-temperature-hardiness of plants and is a new foreign gene in improving the cold and freezing tolerance of transgenic plants.