小麦microRNA167e的特征及表达模式分析

Characterization and Expression Patterns of microRNA167e in Wheat

MicroRNAs(miRNAs)是一类在植物发育调控和逆境胁迫响应过程中发挥重要功能的小RNA,为了探讨miR167e在小麦中的生物学功能,以小麦品种中国春、豫麦18和矮抗58为材料,利用RT-PCR技术克隆了小麦miR167家族基因新成员 MIR167e,并采用qRT-PCR技术分析了其时空表达特性及其对渗透胁迫的响应模式。结果将小麦 MIR167e基因定位在第5同源群染色体的短臂上,将该基因A、B和D基因组的三个部分同源基因分别命名为 TaMIR167e-5AS、 TaMIR167e-5BS和 TaMIR167e-5DS。序列分析显示,该miRNA前体区域在所检测品种间高度保守,3个部分同源基因间仅存在SNP差异,在成熟tae-miR167e对应区域完全一致。时空表达特性分析显示,tae-miR167e在籽粒发育过程中表达呈上调趋势,在不同组织间的表达差异较大,其中在3叶期,叶片和根系中表达量较高,种子中次之,穗下节中表达量最低;在干旱胁迫条件下,该miRNA受胁迫诱导而上调表达,与中国春相比,矮抗58根系中该miRNA的诱导表达启动更快,在叶片中的表达水平更高;在盐胁迫条件下,该miRNA在根系中呈下调表达趋势,而在叶片中上调表达。推测tae-miR167e在小麦发育调控和渗透胁迫响应过程中发挥重要功能。

MicroRNAs(miRNAs)are a group of small RNA molecules that play important roles in the process of developmental regulation and stress response in plant.In order to understand the biological function of MIR167 e in wheat,a new member of the MIR167 family,MIR167 e,was cloned by RT-PCR from wheat cultivars of Chinese Spring,Yumai 18 and Aikang 58,respectively.Additionally,the spatiotemporal expression patterns of the miRNA,as well as its response to osmotic stress,were characterized by qRT-PCR.The results showed that MIR167 e was located on the short arm of chromosome 5,and the its three homologous genes from genome A,B and D were designated as TaMIR167 e-5 AS,TaMIR167 e-5 BS and TaMIR167 e-5 DS,respectively.By using the RT-PCR technology,the cDNA fragments of three homologous genes were cloned from wheat cultivars of Chinese Spring,Yumai 18 and Aikang 58,respectively.Sequence analysis showed that the region of miRNA precursor was highly conserved among the tested varieties,and only SNPs were detected among the three homologous genes,while the sequence corresponding to the mature miR167 e was identical.The spatiotemporal expression profiles detected by RT-qPCR techniques indicated that tae-miR167 e was gradually up-regulated during the process of grain development,while differentially expressed among the tested tissues.The expression level of tae-miR167 e was the highest in leaves and roots at three-leaf stage,followed by that in seeds,and the expression level was the lowest in the peduncle.Under the drought stress,tae-miR167 e was up-regulated and the induction responding to drought stress was faster in root tissues of Aikang 58 than that of Chinese Spring,and the expression level in leaves was higher than that in Chinese Spring.Under salt stress,the tae-miR167 e was down-regulated in root tissues,while up-regulated in leaf tissues.Our results indicated that tae-miR167 e played important roles in the process of developmental regulation and osmotic stress response in wheat.