岷江百合中黄瓜花叶病毒诱导LrNAC转录因子基因的克隆及表达

Cloning and expression analysis of LrNAC transcription factor gene from Lilium regaleinduced by cucumber mosaic virus

【目的】探索岷江百合(Lilium regale)的抗病毒病机制,为开展百合抗病毒育种工作奠定基础。【方法】对岷江百合叶片接种黄瓜花叶病毒(CMV),采用RACE技术克隆岷江百合NAC转录因子基因(LrNAC),对其全长cDNA序列进行生物信息学分析;利用实时荧光定量PCR对LrNAC转录因子基因的器官特异性及CMV侵染后该基因的表达模式进行分析。【结果】LrNAC转录因子基因全长827bp,可编码由208个氨基酸组成的蛋白质,该蛋白具有NAC家族保守结构域;该蛋白为碱性、亲水性、非分泌、不具跨膜区蛋白;分子质量为23.4ku,等电点为9.48。LrNAC转录因子基因在岷江百合嫩叶中相对表达量最高,在嫩茎中最低;该基因可以被CMV诱导上调表达,CMV处理后岷江百合、卷丹(L.lancifolium)和宜昌百合(L.leucanthum)中,LrNAC转录因子基因的相对表达量分别在处理后4d、3d和4d达到最大值,分别为处理前的38倍、3倍和13倍。【结论】LrNAC转录因子基因在岷江百合抗黄瓜花叶病毒防御反应过程中发挥作用。

【Objective】This study investigated disease resistance mechanism of Lilium regale against cucumber mosaic virus(CMV)to improve breeding of antiviral lily.【Method】Leaves of L.regale were treated by CMV and RACE technology was performed to clone the full length of NAC transcription factor gene(LrNAC).The obtained cDNA sequence was analyzed using bioinformatics methods.Real-time PCR was used to assess the expression of LrNACtranscription factor gene in different organs of L.regale and the expression pattern was analyzed.【Result】The full cDNA of LrNACtranscription factor gene was 827 bp and it encoded a 208-amino acid peptide with a conserved domain of NAC transcription factor family.The protein without across the membrane was basic,hydrophilic and not secretory.The deduced sequence of amino acids of LrNAChad a calculated molecular weight of 23.4ku with a pI of 9.48.The relative expression level of this gene was highest in tender leaves,while lowest in tender stems.LrNACtranscriptionfactor gene was up-regulated by CMV.After being inoculated by CMV,this gene peaked on 4d,3dand 4d in L.regale,L.lancifoliumand L.leucanthum,respectively and the maximum expression values of treated samples were 38,3and 13 times larger than the untreated ones.【Conclusion】LrNACtranscription factor gene played a role in L.regale against CMV.