摘  要：硝态氮是旱地植物吸收氮素的主要形式，其吸收与硝酸盐转运蛋白1（NRT1）密切相关。高粱（Sorghum bicolor）较耐贫瘠，对土壤中的氮素吸收和利用效率较高。以拟南芥、水稻的NRT1为基础，通过Blast筛选高粱核酸和蛋白数据库获得SbNRT1基因全长序列，并结合生物信息学方法鉴定出了20个SbNRT1基因，对其进行基因结构、系统进化树、基因表达、选择进化分析，同时对其蛋白质的理化性质、二级和三级结构进行分析。结果显示：SbNRT1分布于SBI-01～SBI-10上（除SBI-08）；SbNRT1蛋白质均为疏水性蛋白，绝大多数蛋白质没有信号肽，且亚细胞定位在质膜上；二级结构以α-螺旋和无规则卷曲为主，SbNRT1蛋白三级结构与预测一致，可信度均达到93%；SbNRT1存在8个分支，高粱与谷子、玉米的NRT1同源关系更近，且高粱在进化上出现了单双子叶的分化；Sobic.004G193000基因在生育期多个部位表达水平较高，Sobic.001G133900、Sobic.003G295500和Sobic.001G302800在高粱根部受硝酸盐诱导表达，也受铵盐和尿素诱导；高粱种质基因组重测序数据计算的ka/ks值表明，SbNRT1的进化具有纯化效应。该研究结果为进一步探讨高粱氮高效相关基因的功能研究提供了基础。
关键词：高粱；NRT1；基因表达；系统进化分析；DNA变异
中图分类号：S514                             文献标志码：ADOI：10.3969/j.issn.1007-7146.2021.05.011

Abstract: Nitrate is the main form of nitrogen absorbed in land plants, and its absorption is highly correlated with function of nitrate transporters (NRT1). Sorghum bicolor is tolerant to nutrient deficiency, and soil nitrogen absorption and utilization efficiency is high. Based on the NRT1 of Arabidopsis thaliana and Oryza sativa, the full length sequence of the SbNRT1 gene was obtained by screening the sorghum nucleic acid and protein database through Blast, and 20 SbNRT1 genes were identified in combination with bioinformatics methods, gene structure analysis, phylogenetic tree analysis, gene expression, selective evolution and protein physicochemical properties, secondary and tertiary structure of SbNRT1 gene family. The results showed that SbNRT1 gene families were distributed on SBI-01～SBI-10, with exception of SBI-08; SbNRT1 proteins are hydrophobic proteins, most of them have no signal peptides, and subcellular localization is mostly on the plasma membrane; the secondary structure is dominated by α-helix and random coils. The SbNRT1 protein family tertiary structure is consistent with predictions, credibility reached 93 percent. SbNRT1 protein family were divided into eight branches. Members of SbNRT1 are more closely related to those of foxtail millet and maize, and appeared in the evolution of single and double cotyledons differentiation. Sobic.004G193000 gene is expressed at a high level in many parts of the growth period. Expression of Sobic.001G133900, Sobic.003G295500 and Sobic.001G302800 are induced in the roots by nitrate and ammonium and urea. ka/ks value calculated based on data for genome resequence for sorghum accession indicated that the evolution of SbNRT1 has purification effect. The results of this study provide a basis for further research on the function of genes related to nitrogen use efficiency in sorghum.
Key words: sorghum (Sorghum bicolor); NRT1; gene expression; systematic evolutionary analysis; DNA variation
（Acta Laser Biology Sinica, 2021, 30(5): 459-467）