硝酸还原酶基因启动子NRE2元件缺失对烟草氮代谢的影响

为了探究硝酸还原酶基因启动子中硝酸盐响应元件NRE2缺失对烟草植株氮代谢的影响,以烤烟品种K326为材料,采用CRISPR/Cas9基因编辑技术获得了烟草NIA1和NIA2基因启动子中NRE2元件缺失的突变体材料,并于同一氮素营养条件下培养,测定烟草植株氮代谢相关生理指标。结果表明,与野生型相比,单突变体和双突变体叶片中的硝酸还原酶活性下降了18.1~25.6个百分点,NO₃^-含量下降了1.5%~4.3%,亚硝酸还原酶活性和NO₂^-含量仍保持在较高水平;单敲除突变体的总氮含量与野生型相比无显著差异,双敲除突变体的总氮含量显著下降了0.88个百分点。本研究为深入了解硝酸盐调控网络以及选育低硝酸盐积累的烟草新品种提供了理论依据。

Effect of NRE2 Element Deletion of Nitrate Reductase Gene Promoter on Nitrogen Metabolism in Tobacco

In order to explore the effect of deletion of NRE2 in nitrate reductase gene promoter on nitrogen metabolism in tobacco plants,CRISPR/Cas9 gene editing technology was used to obtain mutant materials with deletion of NRE2 in NIA1 and NIA2 gene promoters of tobacco by using flue-cured tobacco variety K326 as material.All materials were cultured under the same nitrogen nutrient conditions and the physiological indicators related to nitrogen metabolism of tobacco plants were measured.Results showed that compared with the wild type,the nitrate reductase activity in the leaves of the single and double mutants was decreased by 18.1~25.6 percent,the NO₃^-content was decreased by 1.5%~4.3%,while the nitrite reductase activity and NO₃^-content remained at a high level;the total nitrogen content of the single knockout mutant was not significantly different from that of the wild type,but the total nitrogen content of the double knockout mutant was significantly reduced by 0.88 percent.This study provided theoretical basis for further understanding of nitrate regulatory network and breeding new tobacco varieties with low nitrate accumulation.