【摘要】 植物水孔蛋白作为水分快速跨膜运输的通道蛋白,在保持细胞内外渗透平衡、调节气孔运动以及参与渗透胁迫应答等方面发挥着重要的作用。本研究以‘通蓖5号’叶片为材料,利用RT-PCR的方法成功克隆了两个液泡膜内源水孔蛋白基因的ORFs,将其命名为RcTIP1;2和RcTIP1;3。基因结构分析显示RcTIP1;2和RcTIP1;3均含有3个外显子和2个内含子。生物信息学分析表明2个基因编码的蛋白均含有6个跨膜螺旋以及MIP超家族典型的2个"NPA"保守结构域。多重序列比对发现RcTIP1;2与PtTIP1;2同源性高达84.92%,RcTIP1;3与AtTIP1;3同源性高达79.76%。进化树分析表明2个基因均属于TIP1类亚家族蛋白成员。qRT-PCR分析表明RcTIP1;2与RcTIP1;3基因受冷胁迫均下调表达,该基因的下调表达可能有助于抵抗和延缓冷冻诱导的细胞脱水。进一步对RcTIP1;2与RcTIP1;3调控冷响应的分子机理进行研究,从而为蓖麻分子辅助育种提供重要的理论依据。更多还原

【Abstract】 Plant aq uaporins are water channels for rapid transmembrane transport of water, which play critical roles in maintaining intracellular and extracellular osmotic balance, regulating stomatal movement and osmotic stress responses. Here, we reported two tonoplast intrinsic proteins, RcTIP1;2 and RcTIP1;3, isolated from leaves of ’Tongbi5’ castor bean using RT-PCR method. Gene structure analysis showed that the two genes both contained three exons and two introns. Bioinformatics analysis revealed that the two predicted proteins contained six transmembrane helices and two typical "NPA" motifs of MIP family. The multiple sequence alignment displayed that RcTIP1;2 and RcTIP1;3 had 84.92% and 79.76% amino acid identity with PtTIP1;2 and AtTIP1;3 separately.Phylogenetic analysis demonstrated that the two genes belonged to TIP1 subgroup. qRT-PCR analysis showed that expression of RcTIP1;2 and RcTIP1;3 was down-regulated by cold stress. Down-regulation of two genes might contribute to resist and/or delay freezing-induced cell dehydration. Furthermore, cold response molecular mechanism regulated by RcTIP1;2 and RcTIP1;3 will be studied, which can provide an important theoretical basis for castor molecular assisted breeding.更多还原