【摘要】 LBD转录因子是高等植物特有的一类转录因子。为研究不结球白菜LBD基因对硝酸盐吸收的影响，以紫色不结球白菜自交系NJZX3-4为材料，采用同源克隆的方法克隆BcLBD37基因；通过构建PRI101过表达载体，异缘转化拟南芥，实现BcLBD37基因的过表达；同时借助病毒介导的基因沉默技术（VIGS）,使不结球白菜中的BcLBD37基因沉默；并利用实时荧光定量PCR（qRT-PCR）分析BcLBD37基因过表达以及沉默后对硝酸盐吸收相关基因表达量的影响。结果表明，该基因片段长度为840 bp,编码279个氨基酸。与野生型相比，转基因拟南芥中硝酸盐代谢相关基因NIA1、NIA2、NRT1.1、NRT1.7、NRT2.1、NRT2.5的表达量均显著下调，硝酸还原酶活性和硝态氮含量亦显著降低。而在不结球白菜中沉默该基因后，沉默植株PTY-2/4中硝酸盐代谢相关基因的表达显著上调，硝酸还原酶活性和硝态氮含量亦显著提高。综上可知，BcLBD37基因通过抑制硝酸盐代谢相关基因的表达，调节硝酸还原酶的活性，进而抑制NO^-₃的吸收。本研究为提高不结球白菜营养品质提供了理论依据。更多还原

【Abstract】 LBD transcription factors are a kind of transcription factors unique to higher plants. They play critical role in the regulation of nitrate metabolism. In order to study the effect of LBD gene on nitrate absorption, BcLBD37 was cloned by homologous cloning with purple non-heading Chinese cabbage inbred line NJZX3-4. The PRI101 overexpression vector was constructed and transformed into Arabidopsis thaliana to overexpress BcLBD37 gene. Besides, BcLBD37 in non-heading Chinese cabbage seeding was silenced by virus-induced gene silencing technology（VIGS）. The effects of overexpression and knocked-down BcLBD37 on the expression of nitrate absorption related genes were analyzed by real-time fluorescence quantitative PCR（qRT-PCR）. The results showed that the gene was 840 bp in length and encoded a protein with 279 amino acids. Compared with the wild type, the expression of nitrate metabolism related genes NIA1, NIA2, NRT1.1, NRT1.7, NRT2.1, NRT2.5 in transgenic Arabidopsis thaliana was significantly reduced, and nitrate reductase activity and nitrate nitrogen content were also significantly reduced. After silencing the gene in non-heading Chinese cabbage, the expression of nitrate metabolism related genes in silenced plant PTY-2/4 was significantly increased, and nitrate reductase activity and nitrate nitrogen content were also significantly increased. In conclusion, BcLBD37 gene regulates the activity of nitrate reductase by inhibiting the expression of genes related to nitrate metabolism, thereby inhibiting the absorption of NO^-₃. The present study provides a theoretical basis for improving the nutritional quality of non-heading Chinese cabbage.更多还原