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硝酸盐不仅是植物氮代谢途径中的主要营养成分,也是植物生长发育中的重要信号分子.硝酸盐的吸收特性和转运机制已成为植物生理学和植物分子生物学领域的研究热点.本研究从盐生杜氏藻中克隆到一个硝酸盐转运蛋白基因DsNRT2.1-1,通过氨基酸序列比对分析,发现DsNRT2.1-1与24个植物高亲和性硝酸盐转运蛋白(NRT2)序列的同源性高达66%.在不同浓度硝酸盐诱导下,通过半定量RT-PCR方法分析DsNRT2.1-1基因的表达模式,结果表明DsNRT2.1-1基因在低浓度硝酸盐诱导下表达,而高浓度硝酸盐则抑制其表达.当外源添加不同浓度的硝酸盐代谢产物NH4+或天冬氨酸或谷氨酸时,DsNRT2.1-1基因的表达明显受到上述产物的反馈抑制.在NaCl胁迫条件下,高浓度的NaCl可以诱导DsNRT2.1-1基因的表达.表达DsNRT2.1-1基因的大肠杆菌在0.69 mol/L NaCl胁迫下表现出对盐的耐受性.上述研究结果有助于深入研究盐生杜氏藻硝酸盐转运蛋白的作用机理,同时暗示DsNRT2.1-1基因在作物耐盐分子育种中具有一定的应用前景.
Nitrate is not only the main nutrient component in plant nitrogen metabolism, but also the important signal molecule in plant growth and development.The absorption characteristics and transport mechanism of nitrate have become the research hotspots in plant physiology and plant molecular biology.In this study, DsNRT2.1-1, a nitrate transporter gene, was cloned from Dunaliella salina. The homology of DsNRT2.1-1 with the high-affinity NRT2 sequences of 24 plants was found by amino acid sequence alignment analysis Up to 66% .The expression pattern of DsNRT2.1-1 gene was analyzed by semi-quantitative RT-PCR under different concentrations of nitrate, the results showed that the DsNRT2.1-1 gene was expressed under the condition of low concentration of nitrate and high Concentration of nitrate inhibited its expression.The expression of DsNRT2.1-1 gene was obviously inhibited by the above products when exogenous added different concentration of nitrate metabolites NH4 + or aspartic acid or glutamic acid.When NaCl stress , The high concentration of NaCl can induce the expression of DsNRT2.1-1 gene.The Escherichia coli expressing DsNRT2.1-1 gene showed salt tolerance under 0.69 mol / L NaCl stress.The above results are helpful In-depth study Green algae Dunaliella mechanism nitrate transporter, and hinted DsNRT2.1-1 gene having a certain application in molecular breeding salt-tolerant crops.