摘要： NLP转录因子是植物特有的一类转录因子家族，在植物氮素吸收、转运和同化过程中发挥重要作用。为了解NLP基因在藜麦中的全基因组特征和表达模式，利用生物信息学方法在藜麦基因组中鉴定出9个藜麦NLP基因家族成员，并对其理化性质、染色体定位、基因结构、蛋白保守结构域、保守基序、系统进化以及在不同氮素水平处理下的表达模式进行了分析。结果表明，藜麦9个NLP基因分布于7条染色体上；每个成员含有4～5个外显子、3～4个内含子以及上游非翻译区；启动子中包含有大量激素和胁迫响应的顺式作用元件，其中，在CqNLP3和CqNLP4的启动子区域均预测到1个氮素响应元件GCN4。藜麦NLP蛋白长718～952个氨基酸，分子质量为80.48～104.86 ku，等电点5.31～6.50；每个成员都含有RWP-RK和PB1共2个保守结构域，其在蛋白中的位置具有很高的相似性，保守基序的分析进一步证实了这2个结构域的保守性。系统进化分析表明，9个藜麦NLP家族成员可分为Class Ⅰ，Class Ⅱ和Class Ⅲ共3组，其在进化关系上与拟南芥的亲缘关系更近。在缺氮条件下，CqNLP2、CqNLP3、CqNLP5和CqNLP8表达受到抑制，低氮下则诱导表达；低氮处理后期，CqNLP9的表达量急剧增加。荧光定量PCR表达趋势与转录组数据一致。研究结果可为后续CqNLPs基因克隆和氮素胁迫分析提供参考依据。

关键词: 藜麦, NLP转录因子, 生物信息学, 基因表达, 氮胁迫

Abstract: NLP (Nin-Like Protein) transcription factors belong to a plant-specific transcription factors family, which play an important role in plant nitrogen uptake, transport and assimilation. To understand the whole genome characteristics and expression pattern of NLP gene in quinoa, nine members of quinoa NLP gene were identified via bioinformatics method, and their physical and chemical properties, chromosome location, gene structure, protein conserved domain, conserved motif, systematic evolution and expression profile under different nitrogen levels were analyzed. The results showed that 9 NLP genes of quinoa were distributed on 7 chromosomes, each member contained 4-5 exons, 3-4 introns and up-stream untranslated region. NLPs promoter contained a large number of cis-acting elements responding to hormone and stress, in which a nitrogen response element GCN4 was predicted in the promoter regions of CqNLP3 and CqNLP4, respectively. The length of quinoa NLP protein was 718-952 aa, the relative molecular weight was 80.48-104.86 ku, and the isoelectric point was 5.31-6.50. Each member contained 2 conserved domains, RWP-RK and PB1, and their site on the protein were highly similar. The analysis of conserved motifs further confirmed the conservation of these two domains. Phylogenetic analysis showed that 9 NLPs could be divided into three groups, Class Ⅰ, Class Ⅱ and Class Ⅲ, and they showed closer relationship to Arabidopsis thaliana. The expression of CqNLP2, CqNLP3, CqNLP5 and CqNLP8 was depressed under nitrogen deficiency treatment, but induced under low nitrogen condition. The expression of CqNLP9 increased sharply in the late stage of low nitrogen treatment. The expression pattern of CqNLPs with qRT-PCR was consistent with that of transcriptome data. The results of this study would provide a reference basis for subsequent CqNLPs gene cloning and nitrogen stress analysis.

Key words: Chenopodium quinoa Willd., NLP transcription factor, Bioinformatics, Gene expression, Nitrogen stress

中图分类号: 

• S519