Abstract:

【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.

Key words: TaSOD1.1 and TaSOD1.2 genes of wheat (Triticum aestivum L.), genetic transformation, tobacco, low- temperature tolerant capacity