烟草NtGT-2基因的克隆及表达分析

Cloning and expression of NtGT-2 gene from Nicotiana tabacum

Trihelix转录因子(Trihelix transcription factors)是调节植物生长发育的一类重要的转录因子,在植物抵御各种逆境胁迫过程中发挥重要作用.为研究烟草中Trihelix转录因子,以普通烟草品种K326为试验材料,采用基因同源克隆方法从烟草中克隆到一个Trihelix转录因子基因.生物信息学分析结果显示,该基因属于Trihelix转录因子GT-2亚家族,其开放阅读框(ORF)为1176 bp,共编码391个氨基酸,预测分子量为45.01 kDa,等电点为5.80,命名为NtGT-2.二级结构分析发现NtGT-2蛋白含有一个Trihelix家族典型的Trihelix保守结构域(SANT结构域)和一个卷曲螺旋结构域(Coiled-coil结构域).实时荧光定量PCR结果表明,该基因在烟草的不同组织中表达量具有一定的差异性,在茎节、茎秆及腋芽中的表达量较高,在叶片(5叶、15叶)和根中(侧根、须根)的表达量较低.研究还发现该基因对脱落酸(10μmol/L ABA)、高盐(200 mmol/L NaCl)、低温(4℃)和15%PEG6000处理具有不同程度应答,推测该基因在烟草抵御非生物胁迫中发挥作用.

Trihelix transcription factors are a class of important transcription factors that regulate plant growth and development,and play important roles in the plant resistance to various stresses.In order to investigate Trihelix transcription factors in tobacco,a Trihelix transcription factor gene was cloned from tobacco by gene homologous cloning method and named as NtGT-2.Bioinformatics analysis showed that NtGT-2 gene belonged to the GT-2 subfamily of Trihelix transcription factors,and its maximum open reading frame(ORF)was 1176 bp,which encoded a total of 391 amino acids.The molecular weight of NtGT-2 was predicted to be 45.01 kDa with an isoelectric point of 5.80.The secondary structure analysis indicated that NtGT-2 protein contained a typical Trihelix family structure domain(SANT structure domain)and a curly spiral structure domain(Coiled-coil structure domain).The results of real-time fluorescence quantitative PCR showed that the expressions of NtGT-2 in different tissues of tobacco were different,and the expression level was higher in stalk nodes,stalks and axillary buds and lower in leaves and roots.NtGT-2 had different responses to abscisic acid(10μmol/L ABA),salt stress(200 mmol/L NaCl),low temperature(4℃),and 15%PEG6000 treatment,which suggested that NtGT-2 could play an important role in tobacco resisting abiotic stress.