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烟草是重要的模式植物和经济作物,盐害和干旱两种环境因子对其生长发育、产量和品质都危害很大。为了提高烟草的耐盐抗旱性,本研究利用农杆菌介导的遗传转化法在烟草中过量表达了碱蓬液泡膜Na~+/H~+逆向转运基因SsNHX1,对转基因烟草的耐盐及抗旱性进行表型鉴定和各项生化指标的检测,以期得到耐盐抗旱表性良好的SsNHX1转基因烟草。表型分析发现,SsNHX1基因过表达株系L1和L5的抗盐能力比野生型显著提高,表现为盐胁迫条件下仍能保持旺盛的生长且根系的伸长未受抑制。SsNHX1过表达株系在叶片和根系中积累了更多的Na~+和K~+,同时Na~+含量增长速率较快,而K~+含量降低速率较缓,并可维持较高的叶片相对含水量和叶绿素含量,及较低的丙二醛含量和相对电导率。干旱胁迫发现,过表达株系受干旱胁迫程度更小,并在复水后迅速恢复正常生长。同时,过表达株系的丙二醛含量和相对电导率显著低于野生型,且维持了较高的叶片相对含水量及叶绿素含量。这些结果说明SsNHX1基因在烟草中过量表达后,降低了盐胁迫和干旱胁迫对烟草根系及细胞膜的损伤,并通过调节离子含量、降低细胞的渗透势,维持了叶片较高的相对含水量和叶绿素含量,最终提高了烟草的抗盐和抗旱性。
Tobacco is an important model plant and economic crop. Both environmental factors, salt damage and drought, are harmful to the growth, yield and quality of tobacco. In order to improve the salt tolerance and drought resistance of tobacco, Agr-mediated genetic transformation was used to overexpress the Na + / H + antiporter gene SsNHX1 in Nicotiana tabacum, which is resistant to salt and drought in transgenic tobacco Sex phenotypic identification and biochemical detection, in order to get good salt tolerant drought table SsNHX1 transgenic tobacco. Phenotypic analysis revealed that the salt tolerance ability of SsNHX1 overexpression lines L1 and L5 was significantly higher than that of the wild type, showing that the SsNHX1 overexpression lines maintained vigorous growth under salt stress and the root elongation was not inhibited. SsNHX1 overexpression accumulated more Na ~ + and K ~ + in leaves and roots, Na ~ + content increased faster, while K ~ + decreased more slowly and maintained higher leaves Relative water content and chlorophyll content, and lower MDA content and relative conductivity. Drought stress found that overexpression lines were less drought-stressed and regained their normal growth immediately after rehydration. At the same time, MDA content and relative conductivity of overexpression lines were significantly lower than those of wild type, and higher relative leaf water content and chlorophyll content were maintained. These results indicated that SsNHX1 gene overexpression in tobacco decreased the damage to root and cell membrane of tobacco by salt stress and drought stress and maintained the higher relative water content and chlorophyll content by adjusting the ion content and cell osmotic potential Content, eventually increasing the salt and drought resistance of tobacco.