超表达小麦基因TaSOD1.1和TaSOD1.2对烟草耐低温能力的影响

 【目的】研究超表达小麦基因TaSOD1.1和TaSOD1.2对烟草耐低温能力的影响。【方法】采用农杆菌介导的遗传转化技术，获得融合靶基因的转基因烟草植株;通过比较低温处理后对照和转基因系的表型和生理指标，鉴定超表达靶基因对烟草耐低温能力的调控效应。【结果】以分子检测鉴定的插入单拷贝基因的4个转基因系和对照为材料，低温处理后超表达外源基因的转基因植株叶片失绿缓慢，叶片超氧化物歧化酶（SOD）活性明显增加，反映细胞膜质过氧化程度的丙二醛（MDA）含量明显下降;叶片叶绿素a、b和类胡萝卜素含量、可溶性糖含量和可溶性蛋白含量均明显提高。【结论】超表达小麦TaSOD1.1和TaSOD1.2的烟草植株，具有增强SOD活性、明显缓解低温造成的细胞膜质过氧化程度、改善低温胁迫下植株的生理功能，可进而改善植株抵御低温胁迫的能力。

Improvement of Low-Temperature Stress Tolerant Capacities in Transgenic Tobacco Plants from Overexpression of Wheat TaSOD1.1 and TaSOD1.2 Genes

【Objective】 To elucidate the effects of overexpression of wheat TaSOD1.1 and TaSOD1.2 genes on low-temperature stress tolerant capacities in tobacco. 【Method】 The transgenic tobacco plants fused the target genes were generated based on Agrobacterium tumerficiens- mediated transformation approach. The regulation effects of target genes on low-temperature stress tolerant capacities were evaluated by the comparisons of plant morphology and physiological parameters among the transgenic lines and control (CK) after low-temperature treatment. 【Result】 The transgenic lines with one copy of inserted genes were used as the experimental materials. After low-temperature stress treatment, compared to control and the silenced target gene line TaSOD1.1-a, the transgenic plants with high expression levels of the target genes had obvious higher superoxide dismutase (SOD) activities, so had the higher contents of chlorophyll a, b, and caroteroid, and the contents of soluble sugar and soluble protein. In the meantime, the malondialdehyde (MDA) content was much lower. 【Conclusion】 Overexpression of wheat TaSOD1.1 and TaSOD1.2 genes increased SOD activities and decreased MDA content, resulting in the lessening degree of over-oxidation of the cellular membrane system and the enhancement of physiological functions, and finally improved the low-temperature stress tolerant capacities in transgenic tobacco plants.