小麦NF-Y型转录因子基因TaNF-YC1介导烟草植株抵御渗透协迫功能研究

Study on the function of wheat NF-Y transcription factor gene TaNF-YC1 to resist osmotic stress in tobacco plant

渗透胁迫逆境限制植株生长和发育,增强作物渗透胁迫抵御功能有助于实现作物高产优质目标。本研究以应答渗透逆境小麦NF-YC家族转录因子基因TaNF-YC1为基础,旨在阐明该基因在介导烟草植株抵御干旱和盐分逆境中的功能。系统进化分析表明,TaNF-YC1与部分植物种属NF-Y家族成员在核苷酸序列组成上高度相似。干旱和盐分胁迫处理下TaNF-YC1的转录水平均明显上调,且逆境诱导增多的该基因转录本在正常恢复处理下不断减少。通过检测农杆菌介导烟草叶片转化的融合蛋白信号特征,表明TaNF-YC1蛋白经内质网分选后定位于细胞核内。与野生型相比,干旱和盐分处理下,正义表达TaNF-YC1烟草转基因植株长势改善、干重增加、光合碳同化能力增强;与此相反,反义表达烟草转基因植株渗透胁迫处理下的植株长势变差、干重降低、光合能力减弱。干旱处理下,正、反义转基因植株叶片气孔关闭速率分别呈加快和缓慢特征。本研究发现,TaNF-YC1对渗透逆境产生明显应答,通过调控气孔关闭影响渗透胁迫下植株光合和物质生产能力,在介导植株抵御渗透胁迫逆境中发挥重要功能。

Osmotic stresses inhibit drastically the growth and development of plants.Improvement of plant adaptation to osmotic stresses helps realizing the goal of plant high yield and elite quality production.This investigation aimed at elucidating the function of TaNF-YC1,a NF-Y transcription factor family member in wheat that was responsive to osmotic conditions,in mediating plant tolerance to drought and salt stresses in tobacco lines.Phylogenetic analysis indicated that TaNF-YC1 shared high similarities to a subset of its plant homologous genes.Under drought and salt stress treatments,the expression levels of TaNF-YC1 are significantly upregulated in wheat plants and the stressinduced transcripts of this gene were gradually restored following a normal recovery treatment.Based on detection of the cellular localization of signals initiated by Ta NF-YC1-GFP in transiently expressed tobacco leaves mediated by A.tumerfaciens,TaNF-YC1 protein was shown to be targeted onto nucleus at subcellular level.Compared with the wild type(WT),the transgenic tobacco plants with TaNF-YC1 overexpression displayed improved growth phenotype,increased plant biomass,and elevated photosynthetic function.In contrast,the transgenic plants with TaNF-YC1 knockdown expression showed alleviated phenotype,lowered plant biomass,and decreased photosynthetic capacity.Under drought treatments,the plants of transgenic lines with TaNF-YC1 overexpression and knockdown expression exhibited promotion and inhibition effects on stomata closing rate,respectively.Our results suggest that TaNF-YC1 responds to osmotic stresses at transcription level.It plays an important role in mediating plant adaptation to drought and salt stresses through regulating stomata closing rate,which further affects photosynthetic function and dry matter production of the plants.