川续断DaNAC基因家族成员的鉴定及表达分析

Identification and expression analysis of the DaNAC transcription factor family in Dipsacus asper

NAC基因在植物的逆境胁迫及次生代谢等过程具有重要的调控作用。为挖掘参与川续断皂苷Ⅵ合成的NAC基因家族成员,本研究利用川续断根、茎、叶、花、种子等不同组织构建的全长转录组数据库筛选包含完整开放阅读框的NAC家族成员,对其进行保守结构域及motif分析、进化树比对分析、组织表达差异分析和逆境胁迫诱导表达分析。本文共筛选得到29个NAC家族成员,在N端都具有NAC基因家族特有的NAM结构域以及保守的motif 1和motif 2;其中5个DaNAC蛋白和拟南芥及水稻中与逆境胁迫有关的NAC亲缘关系较近,共同聚在GroupⅠ亚家族;qRT-PCR表达分析发现,DaNAC基因在叶片中表达量较高,其次是根、茎、叶柄,在花和种子中表达量最低;15℃低温处理川续断后,川续断4个DaNAC基因均受低温诱导上调表达,但表达模式存在一定的差异;另外,34564NAC2、33883NAC48、6727NAC14基因均受150μmol·L-1茉莉酸甲酯的诱导上调表达,34480NAC22基因受茉莉酸甲酯的诱导下调表达。结果表明川续断NAC基因受逆境胁迫诱导表达,为进一步揭示NAC家族成员在川续断逆境胁迫中的作用奠定了基础。

NAC transcription factor genes play an important role in regulating plant adversity stress tolerance and secondary metabolism.To explore DaNAC transcription factor participation in the synthesis of asperosaponinⅥin Dipsacus asper,we analyzed the expression of DaNAC genes based on full-length transcriptome data from different tissues(root,stem,leaf,flower,seed)to provide a theoretical foundation for regulating the metabolism of D.asper.RNA-seq data was used to identify open reading frames.Bioinformatic methods were used to identify the conserved domain motifs and construct an evolutionary tree.qRT-PCR was carried out to analyze tissue-specific and adversity-stressed expression.Twenty-nine DaNAC sequences were identified,all of which contain the conserved NAM domain and conserved motif 1 and motif 2 at the N terminal.Five DaNAC genes are closely related to the NAC genes in Arabidopsis thaliana and rice that are involved in adversity stress and are clustered in the GroupⅠsubfamily.qRT-PCR revealed that DaNAC genes are differentially expressed between tissues.The expression levels were highest in leaves,followed by roots,stems and petioles,and the lowest in flowers and seeds.Compared with normal growth conditions,the expression of four NAC genes was up-regulated by treatment with low temperature(15℃).The expression of three genes(34564 NAC2,33883 NAC48,6727 NAC14)was up-regulated and one gene(34480 NAC22)was down-regulated by 150μmol·L-1 MeJA.The results illustrate that the expression of NAC genes is induced by adversity stress,which provides a foundation for further study on the role of NAC family members in adversity stress in D.asper.