藜麦NHX基因家族鉴定及盐胁迫下表达分析

Identification and Expression Analysis of NHX Gene Family in Quinoa Under Salt Stress

探讨藜麦NHX基因家族生物学特性及盐胁迫下的表达模式,以期为藜麦抗盐品种选择提供理论依据。以藜麦含有Na+/H+exchange结构域的蛋白质序列为基础,对其基因结构、蛋白质motif、理化性质以及盐胁迫下转录表达进行分析。结果表明,藜麦基因组中含有46个NHXs基因家族成员,氨基酸长度为109-1 820 aa,分子质量为11 472.74-204 381.38 Da,等电点为5.00-9.27,亲水性为-0.226-1.112,不稳定指数为21.71-50.73。进化树分析可以将其分为5个亚组,在进化树中位置相近的NHXs基因具有相近的结构。同一亚组的NHXs蛋白具有相似motif结构,与拟南芥、小麦和玉米为直系同源蛋白,且多数定位在细胞膜和液泡中。通过盐胁迫下藜麦转录组数据分析发现,随盐胁迫时间增加,其中有26个NHXs基因的转录水平提升,9个下降,11个无明显变化。此外,35个受到盐胁迫诱导表达的NHXs基因,通过GO注释发现,主要参与离子、细胞稳态和离子跨膜运输过程。NHXs基因结构和蛋白质motif的多样性,推测不同亚组NHXs在盐胁迫中参与不同的响应过程,其盐胁迫下不同的表达模式也表明在盐胁迫响应过程中发挥重要作用。

To explore the biological characteristics and expression patterns of NHX gene family in quinoa(Chenopodium quinoa Willd.) under salt stress is aimed to provide theoretical basis for the study of quinoa salt tolerance. Based on the protein sequence of quinoa containing Na+/H+ exchange domain, its gene structure, protein motif, physicochemical properties and transcriptional expression under salt stress were analyzed. The results showed that the quinoa genome contained 46 members of the NHXs gene family, and the amino acid length, molecular mass, isoelectric point, hydrophilicity and instability index were between 109-1 820 aa,11 472.74-204 381.38 Da,5.00-9.27,-0.226-1.112and 21.71-50.73,respectively. The phylogenetic tree analysis can be divided into 5 subgroups, and the NHXs genes with similar positions in the phylogenetic tree had similar structures. The NHXs proteins in the same subgroup had similar motif structures and were orthologous to Arabidopsis, wheat and maize, and most of them were localized in cell membranes and vacuoles. Through the analysis of quinoa transcriptome data under salt stress, with the increase of salt stress time, the transcription levels of 26 NHXs genes increased,9 decreased, and 11 did not change significantly. In addition,35 NHXs genes expressions induced by salt stress were mainly involved in ions, cellular homeostasis and ion transmembrane transport processes through GO annotation. Diversity of NHXs gene structure and protein motifs, it is speculated that different subgroups of NHXs were involved in different response processes under salt stress. In addition, the different expression patterns under salt stress also suggest an important role in the process of salt stress.