紫花苜蓿耐盐性相关NAC转录因子的挖掘及表达分析

Excavation and Expression Analysis of NAC Transcription Factors Related to Salinity Resistance of Medicago sativa

NAC(NAM,ATAF1/2,CUC2)是植物特有的一类转录因子家族,可调控植物响应盐胁迫。本研究基于盐胁迫下紫花苜蓿(Medicago sativa L.)耐盐品种GIB和盐敏感品种LS根和叶的转录组数据,通过生物信息学方法筛选出17个差异表达的MsNAC转录因子家族成员,并对其序列特征、系统进化、顺式作用元件及盐胁迫下的表达模式等进行分析。结果显示,17个MsNACs均具有NAC典型的NAM结构域,且蛋白结构相似。系统进化分析将17个MsNACs分成8个亚族,各亚组成员具有高度相似的保守基序。顺式作用元件分析发现,有15个MsNACs具有ABA响应顺式元件ABRE。转录组数据表达模式分析与RT-qPCR验证结果显示MsNAC1,MsNAC2,MsNAC35,MsJUB1和MsNAC40基因在盐处理下GIB叶中上调表达,在LS叶中下调或者未发生变化,推测这些基因参与调控紫花苜蓿的耐盐反应。本研究为进一步研究紫花苜蓿NAC转录因子响应盐胁迫功能提供参考依据。

NAC(NAM,ATAF1/2 and CUC2)is a typical family of transcription factors in plants,which can regulate the response of plants to salinity stress.Based on the root and leave transcriptome analysis of two M.sativa cultivars differing in salinity tolerance,i.e.,GIB(salinity-tolerant)and LS(salinity-sensitive)under salinity stress,17 differentially expressed MsNAC members of the MsNAC transcription factor family were identified,and their sequence characteristics,phylogenetic relationship,cis-elements,and expression patterns under salinity stress were analyzed by bioinformatics methods.The results showed that 17 MsNAC members had typical NAM domains of NAC transcription factor,and their protein structures were similar.These 17 members were divided into 8 subgroups by phylogenetic analysis,and members within the same subgroup showed highly similar conserved motifs.Cis-elements analysis showed that 15 out of 17 MsNACs had ABA-responsive cis-element ABRE.The expression pattern analysis by RNA-seq and RT-qPCR showed that MsNAC1,MsNAC2,MsNAC35,MsJUB1 and MsNAC40 genes were up-regulated by salinity treatment in leaves of GIB,while down-regulated or unchanged in LS,suggesting that these genes were involved in regulating the salinity tolerance of M.sativa.The study provided reference for further study on the function of NAC transcription factor in M.sativa in response to salinity stress.