【摘要】 MicroRNAs(miRNAs)作为一类21碱基左右的非编码小RNAs,参与植物生长发育的调控,并在植物对生物与非生物胁迫的应答过程中发挥重要作用。本研究依据miRNA高度保守特点,利用已公布的毛果杨(Populus trichocarpa)基因组序列设计引物,从甜杨(Populus suaveolens)基因组中克隆获得了12个miRNA基因座序列。序列比对结果表明,这些miRNA基因均为毛果杨低温响应miRNA基因的同源序列。同时,以低温(0℃)处理0～48h的甜杨幼苗为试材,通过半定量RT-PCR法对miRNA基因的成熟体序列在不同处理时间下的表达谱进行分析,结果显示,大多数miRNA成熟体序列在甜杨低温胁迫下的表达模式与其在毛果杨中的表达极为相似,由此可推测这些保守性miRNAs可能在甜杨和毛果杨两物种对低温胁迫的应答反应中发挥相似的功能,而miR168a、miR168b和miR475a在两物种间表达现象的差异,表明它们可能通过调控多种靶基因而发挥不同作用。本文结果将为进一步研究甜杨基因功能提供基础。更多还原

【Abstract】 MicroRNAs (miRNAs) are ～21-nucleotide non-protein-coding small RNAs that play key roles in plant development and response to abiotic stresses.In this paper,12 homologous sequences of cold stress-responsive Ptc-miRNA genes were isolated from the genomic DNA of Populus suaveolens based on conservation of miRNA within and between species.Additionally,the expression profiles of the obtained mature miRNAs from P.suave-olens cuttings exposed to low temperature (0℃) for 0 to 48 hours were analyzed by semi-quantitative RT-PCR.The results showed that the little difference in expression profiles of most mature miRNAs under cold stress between P.suaveolens and P.trichocarpa,suggesting that these conserved miRNAs may play similar roles in response to low temperature stress,while the different expression profiles of miR168a,miR168b and miR475a indicated that they might have different target genes between these two species.The results of this paper would provide some groundwork for further investigating gene function of Populus suaveolens.更多还原