地黄RgMYB10基因的克隆与表达分析

Cloning and Expression Analysis of RgMYB10 Gene in Rehmannia glutinosa

MYB转录因子是植物最大的转录因子家族之一,广泛参与植物的生长发育、逆境胁迫和次生代谢产物积累。该研究通过同源比对和功能注释,在地黄(Rehmannia glutinosa)转录组中筛选出MYB的转录本,设计特异性引物对MYB基因的cDNA序列进行PCR扩增,用水杨酸(SA)、Ag^(+)、茉莉酸甲酯(MeJA)和腐胺(Put)这4种诱导子处理地黄毛状根,并通过实时荧光定量PCR(qRT-PCR)检测候选MYB基因的表达。结果显示:(1)成功克隆到1个地黄MYB基因,命名为RgMYB10;该基因编码247个氨基酸残基,蛋白质相对分子质量28.48 kD,等电点为5.14,属于R2R3-MYB转录因子。(2)qRT-PCR结果显示,RgMYB10在须根中表达量最高,其次为茎,块根中的表达量最低。(3)RgMYB10在MeJA处理后的毛状根中显著上调表达,为特异响应MeJA诱导的基因,推测RgMYB10基因可能是响应MeJA参与地黄毛蕊花糖苷生物合成的关键转录因子。研究表明,地黄MYB10基因可能参与地黄毛蕊花糖苷的生物合成,为进一步研究MYB10基因在地黄毛蕊花糖苷合成中的功能奠定了基础。

MYB transcription factors are one of the largest family of transcription factors in plants,widely involved in plant growth and development,adversity stress,and accumulation of secondary metabolite.Through homology comparison and functional annotation,we screened MYB transcripts in the R.glutinosa transcriptome,and desigend specific primers to amplify MYB gene.Four elicitors including salicylic acid(SA),Ag^(+),methyl jasmonate(MeJA)and putrescine(Put)were further treated on the hairy roots of R.glutinosa,and the expression pattern of the candidate MYB gene were detected by quantitative real-time PCR(qRT-PCR).The results showed that:(1)a MYB gene of R.glutinosa was successfully cloned,named RgMYB10.It encodes 247 amino acid residues,the relative molecular mass of the protein was 28.48 kD,and the isoelectric point PI was 5.14,belongs to the R2R3-MYB transcription factor.(2)QRT-PCR results showed that the expression levels of RgMYB10 was the highest in adventitious roots,followed by stems,and the lowest expression in tuberous roots.(3)The RgMYB10 in hairy roots after MeJA treatment was significantly up-regulated,which was a gene specifically responding to MeJA induction.Therefore,we speculate that RgMYB10 gene may be a key transcription factor involved in the biosynthesis of R.glutinosa acteoside in response to MeJA.The results indicate that RgMYB10 may be involved in biosynthesis of R.glutinosa acteoside,which lays the foundation for further research on the function of RgMYB10 in acteoside biosynthesis.